Monday, December 15, 2008

Climate Change - Invasive Species

Invasive species issues are complex and interlinked with other complex and diverse constructs such as climate and atmospheric change, species shifts and biodiversity, as well as sustainable food and health questions. This interdependency is symptomatic of multifaceted questions that defies linear solutions. Invasive species are themselves, therefore, a threat both to managed agronomic systems (e.g. food supply) as well as ecosystem services (e.g. genetic diversity). Assessment of climate change dynamics in the context of the biological success of invasive species remains one of the most unrecognized threats associated with global warming science.
If the biological success of invasive species is strengthened as a function of climate change, then critical measures must be taken. The first universally recognized step is, to halt and reverse the anthropogenic climate drivers (e.g. human sources of carbon dioxide and other greenhouse gases) responsible for climatic change. Because the globe is already showing signs of climatic uncertainty, a second goal is adaptation science. The two goals are connected and interdependent, but not necessarily so perceived at first glance.

Understanding possible adaptation to changing climate dynamics and researching long term solutions to problems as well as new technologies for dealing with long and short term climatic system change are areas that necessitate support from and the sceitnfic community and the public. For example, while it is reasonable to decry the changes in temperature, carbon dioxide and ozone levels which may produce declining rice yields delivered from current strains of rice, Oryza sativa,how the agricultural community adapts to this challenge will reflect both mitigation and adaptation issues and priorities? How can they do so in the context of unprecedented threats from invasive species?

From a USDA ARS technical abstract, IDENTIFYING AND MANIPULATING DETERMINANTS OF PHOTOSYNTHATE PRODUCTION AND PARTITIONING, researchable issues abound: “Elevated temperature treatments negated any enhancement in rice yield at elevated carbon dioxide, which suggests that identifying high temperature tolerant germplasm will be key to realizing yield benefits in the future.” [Rice Production in a Changing Climate: A Meta-analysis of Responses to Elevated Carbon Dioxide and Elevated Ozone Concentration] (Ainsworth, Elizabeth[lhz1] )

In other words, we need to understand the implications of climate change and we need to be working on adaptation now. Present projections are that we will need an increase of 20% in cereal production (i.e. wheat, rice and corn) to keep pace with population demand by 2020. A report, Food Gap Widening in Developing Countries- One in Four Children Worldwide Will be Malnourished in 2020. October 26, 1997 states that “Demand for cereals, especially for livestock feed, will increase rapidly. People in developing countries are expected to consume twice as much meat in 2020 as they did in 1993, causing demand for feed grain to double.”

How are we going to feed ourselves? How will we clean our water supply? Where will we find air suitable for human life? I may presume too much, but I think it highly unreasonable that we shall go back to a sustainable hunter gather society with the current and project human population numbers. This statement means that we shall need technological solutions with sustainability assumed as a fundamental prerequisite. We shall be in need of technology which recognizes that the earth for the foreseeable future is a closed system with finite resource limits.

The same set of climatic variables that are affecting cereal yields may also be affecting invasive species impacts on both traditional agriculture and current ecosystem management. A clarion call for action from natural area managers has focused on invasive species as a major threat to rare and endangered species. Invasive species have visibly out-competed native species and caused increased pressure on remaining populations. According NatureServe, “Invasive species are now regarded as the second-leading threat to imperiled species, behind only habitat destruction.

Invasive species have also adversely affected agricultural production. A report from the Goodlatte Subcommittee states that “Invasive species represent a serious threat to the viability of American agriculture, forestry, and ecosystems. Not only can these harmful organisms cripple production agriculture, but society pays a great price for these harmful species including unemployment, damaged goods and equipment, power failures, food and water shortages, environmental degradation, increased rates and severity of natural disasters, and disease epidemics. The most obvious harm is found in agriculture. Farmers and ranchers are constantly battling alien pests, weeds, and diseases. Decreases in yield and quality of crops and livestock are easily attributed to invasive species. Producers fight stubborn weeds and pests year round – whether preparing for the planting season, during the growing season or harvest.

The interconnection between climate dynamics, crop production and invasive species is easily seen. All plant species require carbon dioxide, water, light, and nutrients. If one of these resources changes abruptly, plant species will respond differentially. For example, too much water and the cactus dies; too little water and the wetland fern succumbs. Too much sun and the black cohosh is fried; too little sun and the pumpkin will not fruit. Add or decrease atmospheric carbon dioxide and plant species also respond differently, some will have the capacity to process the increase more efficiently; others will quietly be over come by the resulting competition. As carbon dioxide changes in the atmosphere, knowing which species will be more competitive has implications for not only agriculture (e.g. which rice varieties will be the best to grow?) but to invasive species as well (e.g. will kudzu be more of a threat in the future?)

In addition, increasing greenhouse gases such as carbon dioxide can result in changes in precipitation and temperature with subsequent results in species growth and adaptation. Here too, the same issues arise; how will we adapt agriculture to unprecedented changes in the environment that reflect temperature and precipitation extremes? How will these changes affect the success of invasive species and their subsequent impact on agriculture? Such complex issues underlie the need for more and immediate research while underscoring the complex connections between climate change, agriculture and invasive species.

In turn, invasive species concepts and challenges are connected to species shift. Species shift or species migration is movement of species from natural ranges in reaction to climate changes. For the layman this is not too hard a concept as humans do this on a regular basis. Snowbirds to Florida and skiers to the mountains are examples of in extremis of climate migration. In the long historical record of humanity, migrations for food, fuel, fiber, and feed are the movements of legend from the Germanic invasions of Rome to the emigration from Ireland during a time of famine. Species which once were unreliably hardy in Maryland now thrive, including but not limited to kudzu and fire ants.

The question then of ‘nativeness’ is no longer solely a question of where, but also of when. And more importantly, for the purposes of invasive species resource allocation, what are we trying to prevent, what are we trying to preserve exactly? If the threat is to endangered species then what are we to make of species shifts? If the rare and endangered are heading up and north, and the existing ecosystem is being stressed by climate change, what is the purpose of eradication efforts of invasives in ecosystem in flux? At the same time, we do know that preserving complex functioning ecosystems is important for the services provided and that invasive species pressure limits the ability of the system to provide these services, services such as clean water, clean air, and viable habitat.

It is once again not only natural areas which will feel the impact of species shift. “Rangelands will experience regional and local changes in temperature and precipitation. The CO2 has already increased to levels not experienced in the past million years and is projected to continue increasing far in the future. Plants have different sensitivities to temperature. Precipitation and CO2, and research suggest that plant shifts favoring some species over others is underway in rangelands. Research is needed to better understand such plant species shifts which have a tremendous impact on land’s utility. We need to use that knowledge to develop proactive management strategies that will help ranchers and public land managers adapt to climate change.” [From a presentation given to Maryland Senators Mikulski and Cardin’s staff, Dec 2008 )

According to a posting in ScienceDaily (Nov. 30, 2008), “…the distribution of many species is shifting because of climate change and changes in land use.” The feed-back loop of human activity on the environment and the environment’s impact on human activities becomes apparent in the previous quote. According to Dr. Lewis Ziska “one of the fundamental challenges we face in the 21st century is the unprecedented level of human-induced change.” [Controversies in Science Rising Atmospheric Carbon Dioxide and Plant Biology: The Overlooked Paradigm. DNA & Cell Biology Vol 27 Nov 2008]
For me this is a call for immediate and specific research looking for adaptive solutions.

Monday, December 01, 2008

Landscape literacy & the grammar of gardening

“Landscape literacy is the ability to identify, understand, interpret, conserve,create, communicate, preserve, propagate, cultivate, grow and use plants as well as natural and man-made materials associated with varying social contexts. Landscape literacy involves a continuum of learning to enable an individual to achieve his or her goals, to develop his or her knowledge and potential, and to participate fully in the truth of the relation between human beings, their world, and the cause or ground which gives rise to the world. To be landscape literate is to experience or feel the world as intimate and personal; to recognize that this is the world just as it is with out any shadows or hidden meanings. The grammar of landscape allows the experience of the union of man and nature, and the realization of their co-dependent state. The grammar of landscape and the syntax of gardening make possible an understanding and differentiation of what is artifice and what is natural. “ John Peter Thompson

Sunday, November 30, 2008

Invasive English ivy featured in Newsweek..with a twist

Yes that sure looks like Hedera helix wrapped around the U. S. presidential rostrum. (I checked a hard copy of the article) to verify (it is good to have more than fuzzy virtual renditions and copies).

"Give me your hungry, your homeless your plants which need no spraying, and can survive both drought and flood."

English ivy, an invasive species poster child in the mid-Atlantic, is prominently features in a Newsweek article entitled: A Leadership Reality Check Oratory is not enough. It often takes a national crisis to persuade Americans to make sacrifices.

The article is about climate change and warming, with intense nods towards CO2 changes. It is a call for politicians to ask for public sacrifice. However, it is going to be hard to get the public to make sacrifices when we can not get our vices and virtues straight. Featuring an invasive species, most certainly without knowing that the natural area invader is centered in the picture subconsciously raises the question of what else is not quite right about the information thus presented.

This picture in a sense is a reinforcement of the need for systematics (USDA BARC) and basic taxonomy, fields which we publicly and privately fail to support because we blithely assume that someone some where knows. In addition, this photo found on the Internet refutes the notion that we do not need libraries and their collections (NAL) and more importantly librarians to vet our factoids.

The irony of having an invasive species featured front and center in an environmental call to arms in a reputable news magazine is rich and symptomatic of how far we need to go in order to engage in conversations on an equal playing field with all parties having the same access to information.

Newsweek: April 14, 2008 page 48

Tuesday, November 04, 2008

Sustainable Landscape Alternatives:

The Sustainable Sites Initiative proposes an alternative to traditional landscape design principles offering a tool for those who wish to garden, want to limit invasive species' impact, and enhance environmental services. As a member of the technical sub committee on vegetation for this project , I am excited to be part of a new vision for landscaping, as a long time grower and retailer of garden plants and garden solutions, I am delighted to offer my customers a choice.

Sustainable Sites Initiative -

The Sustainable Sites Initiative is an interdisciplinary partnership led by the American Society of Landscape Architects, the Lady Bird Johnson Wildflower Center, the United States Botanic Garden and a diverse group of stakeholder organizations working together to foster a transformation in land development and management practices. Through the creation and implementation of clear and rigorous design, construction, operations, and maintenance criteria, the Initiative aims to supplement existing green building and landscape guidelines as well as to become a stand-alone tool for site sustainability. The U.S. Green Building Council, a major stakeholder in the Initiative, anticipates incorporating the benchmarks into future versions of the LEED® (Leadership in Energy and Environmental Design) Green Building Rating SystemTM.

The Initiative envisions that sustainable land practices will enable natural and built systems to work together to protect and enhance the ability of landscapes to provide services such as climate regulation, clean air and water, and improved quality of life.

Guidelines and Performance Benchmarks Draft 2008Available on November 10thOn November 10th, the Sustainable Sites Initiative will release the Guidelines and Performance Benchmarks Draft 2008 for public comment. This important milestone builds on the initial Standards and Guidelines: Preliminary Report released in November of last year. The new draft will contain over 50 proposed prerequisites and credits ranging from site selection to sustainable maintenance practices. The metrics’ format will be similar to existing LEED tools in structure and will include the following components:

Credit intent
Ecosystem services addressed
Social and economic benefits
Submittal documentation
Technologies and strategies

The Guidelines and Performance Benchmarks Draft 2008 will be available for download and public comment beginning on November 10, 2008 at The public comment period will close January 20, 2009. Public review and comment is essential to the successful development of these guidelines and performance-based benchmarks. To participate in the review process, visit Study Library OnlineThe Sustainable Sites Initiative received over 125 submittals to the call for case studies. These case studies demonstrate a wide variety of sustainable practices addressing issues associated with stormwater management, integrated design process, habitat restoration, material management and other sustainable practices. The Initiative will continue to build this library over time from the wealth of innovative submissions we have received. We appreciate the willingness of these organizations to share their experiences through the case study process. Future opportunities to submit additional case studies will be promoted on the website.

Sunday, October 26, 2008

National Invasive Species Council Advisory Committee will Meet November 2008

The National Invasive Species Council Advisory Committee will meet in Baltimore Maryland, November 18 and 18th, 2008. This is a public meeting, so, if you are in the area, come and join us. The committee, known as ISAC, as part of its agenda, encourages public comment.

If you cannot come, write to me ( so that your observations and comments might be brought to the committee’s attention. ISAC will consider bio-fuels, the federal Management Plan Overview and ISAC Involvement, Cooperative Control and Management of Exotic Fish Impacting Native Fish Populations, updates on USDA Q-37 Permit Regulations, ballast water issues and legislative updates.

Saturday, October 11, 2008

The Dignity of Invasive Species

Nothing is ever simple when it comes to considerations of issues involving invasive species. The seeming immensity of invasive species issues may lead to paralysis of analysis, or may result in stakeholders feeling so overwhelmed that they find no reason to continue working on the challenge. A Mid Atlantic Exotic Pest Plant Council (MA-EPPC) list serve thread noted that “… some of the students have felt that this kind of work is pointless or futile given the size of the problem.“ In a way, this is an outcome of not understanding a key feature of a wicked problem. Wicked problems are non linear and have no end point. The only way a wicked problem ends is by a lack of will or an end of resource.

But the futility of the problem is dwarfed by the students’ limited understanding of the features of a wicked problem. The students are but one of the many stakeholders involved in the issues of invasive species. If they think that weeding, which is what the removal of invasive plant species amounts to in natural areas, is futile, surely they have never met a farmer, who tireless combats unwanted plants in an endless in order to generate the food necessary for life.

To add to the complications of invasive species, a new stakeholder group can be added: “Plant Dignity Interests”. How wickedly inconvenient, to have to consider a botanical species’ dignity? The Federal Ethics Committee on Non Human Biotechnology (ECNH) in Switzerland added to the large group of interested parties to the invasive species discussion, most likely an unintended consequence or opportunity, There are three concepts to understand in order to enter into the possibilities of this line of thinking. First is the “instrumental” value of the species, second, the “relational” value, and third, the “inherent” value. Kudzu, for example, has an “instrumental” value in its ability to control erosion, and a potential “instrumental” value as a bio-fuel source. Kudzu’s “relational” value, while perhaps harder to imagine, is found in its reflection of Asian landscapes, and in its ability to mimic the serenity found in great mono-cultural sweeps (ground covers) of landscape that require little landscape literacy or landscape syntactic knowledge to understand. Kudzu, finally, has, as a member of the community of life on Earth, its own “inherent” worth, independent of the first two attributes.

Now to the students’ lament, we can add Arundo donax and its place in the cosmos. A New Leaf: Making Paper From Weeds An invasive ecological bad guy may be able to paper over his evil ways and absorb some carbon as well. (By: Lisa Conti | October 07, 2008 ) . A third rail of invasive species conversations is valuation. The idea is to put a market price on an invader which at first should help eradicate the problem. The rodent Nutria found in Maryland and Delaware is a destructive pest. Putting a bounty pelts should have resulted in people hunting and trapping the creature to extinction in its non native range of the eastern Chesapeake Bay. Instead, the laws of unintended consequences kicked in, a entrepreneurial folks began to breed the critter, which was already out of control, in order, naturally, to collect the bounty, without the effort

When we add the discussion of Arundo donax’s dignity to the conversation, plus its potential “instrumental” value as well as its gardening or ornamental, its “relational” value, the conversation spins out of control.. How wickedly inconvenient the entire aggregation of concepts becomes, how prone to cross-purposed proposals, we find ourselves in.

Tuesday, September 30, 2008

Tax Choice: for Children or for Invasive Species Issues

With invasive species issues not being exactly front page news, the idea of a government whereby citizens directly indicate which programs each wants funded is attractive. Given that most invasive species issues are discussed by a small circle of interested parties, talking to or at each other, unable to connect their personal issue of interest with the "it" of the moment, such a system would at least put a few dollars towards the issue of their choice. Of course, realistically meaning fewer dollars, many of us would feel good for a few minutes every April 15th.
Sponsor a child, or a noxious weed Monday, 29 September 2008

Taxpayers will have the option (in Hungary) to redirect 1% of their income tax to a scheme to reduce child poverty and sponsor talented youngsters, the government announced last week. Under an existing scheme, Hungarians can opt to have one percent of their income tax donated to a charity of their choice, and a further one percent to a church or religious organisation. Among other possible targets of the scheme mentioned by a government spokesman was an initiative to eradicate the allergenic giant ragweed that is rampant in Hungary.

Sunday, September 28, 2008

Invasive Species: Selling on the Front Lines

Sunday, I took to the sales floor of the garden center to help with sales. Within five minutes of getting there, invasive species opportunities arose in force. As I was helping a customer select a few native plants for her shade garden, I saw and heard a gentleman running after the nursery’s IPM consultant shouting, “Wait! I need to get information on an invasive plant for the shade. Wait!”

Of course the consultant moved on and my wife directed the anxious customer in my direction, pointing out with the approval of the consultant that I was the invasive guy. “I need an invasive plant for my shade garden,” the customer said.

Customer service dictates that rule number one should come into play. Rule number one in retail: The customer is always right. Rule number two: If the customer is wrong, see rule number one.

I now had the delicate job of explaining that he had just approached the National Invasive Species Council Advisory Committee's acting vice chair, and that perhaps there was some information that I could share before we went too far in the actual selection of an invasive species for his garden. I pointed out that on the continuum of bad choices, we could offer to sell him natural area (Maryland) public enemy number one, English ivy, or perhaps just slightly less problematic, periwinkle, and if I had talked him out of those two, Japanese spurge might seal the deal and my doom. Fortunately, he had decided for personal reasons of style and taste that pachysandra was out, and that he had enough vines already.

With further conversation, I was able to introduce him to Christmas fern, and then frantically began to look for Asarum canadensis, only to find that we did not have any in stock. The entire dialogue left me thinking how much work there is to be done at the retail level. We need to provide information in a fashion that allows our customers to make informed choices. Trying to be positive about a negative when someone is trying to give you his money is a touchy, dicey proposition.

Having recovered from this first engagement on the sales floor, I moved to our euphemistically named “chemical” room. I have tried without success to get our staff to call this something else, anything else for years, but after 80 years in business I am stuck with a name appropriate to the 1950’s. A continuous stream of radio traffic from staff includes the phrase :chemical” room while drecting customers to our organic choice area. The irony is apparent only to me So, I thought I would go see what our customers were doing.

Of course, when a customer sees a bug, those who choose the “chemical” room want the maximum toxicity. They usually are not in quibbling mode, so working this part of the business takes a certain deftness on one’s feet not to enrage a home-owner with natural solutions or a live and let live theory of the problem. I was expecting to hear, “Sell me an easy to use, weapon of mass destruction, not to oexpensive solution to my pest challenge.”

What I heard instead, inspired this posting. “I just took some stems and seeds from my buddleia plant to my vacation house and threw them in the woods. They are growing just fine. Can I take some stems this fall after the leaves drop and stick them in the area around the back of my property; will they root?” I was to say the least astonished. I said, “Can I perhaps have discussion with you,” after my sales person told the ladies that I was the wrong person to have overheard the conversation; that I was the resident invasive species…guy, but I did not hear the guy part.

This customer was trying, it turns out, to combat awful weeds along the property line, honey suckle, multiflora roses, et al, by planting or encouraging butterfly friendly plants. Hence the butterfly bush program. After giving the by now standard, this is who I try to be speech, by now refined a little, I pointed out that while she was indeed attracting butterflies, she was missing the point by not planting host plants for the eggs and caterpillars that would eventually become the creatures of beauty she was trying to encourage. I noted that she was bringing one problem to combat another problem and iin the end just encouraging the final destruction of the butterfly habitat she was trying to encourage.

These two chance encounters within the same hour, sent me to the keyboard, to write about invasive species, mostly to those who already know about the problem. Trying to reach my own customers, who walked past my three foot by five foot warning signs and my staff who thinks I have lost my mind, brings to mind Seneca, I think, per aspera ad astra.

Saturday, September 27, 2008

Invasive Species Issues need ITAP

The complexities of invasive species issues demand that we know what we are talking about, that we actually can identify the organisms which we find and that we have some awareness of their relationships to their native ecosystems, so that we can better understand the implications of possible introductions to alien ecosystems. To this end, we have ITAP, Federal Interagency Committee on Invasive Terrestrial Animals and Pathogens.

"ITAP's mission is to support and facilitate more efficient networking and sharing of technical information for program planning and coordination among Federal Agencies and Departments involved with invasive species research and management. ITAP focuses on several major taxonomic groups of invasive species for which improved technical coordination is essential to facilitate effective Federal responses. ITAP's mission parallels and complements the missions of the Federal Interagency Committee for the Management of Noxious and Exotic Weeds (FICMNEW) and the Aquatic Nuisance Species Task Force (ANSTF)."

The lack of understanding which accompanies systematics, the core of all identification id abysmal. This lack of support is resulting in a decline of taxonomic programs, and a looming problem as experienced systematics professionals retire with no specialists to follow. The various collections of the United States, and the world are in various states of decline. Somehow, we think that everything we need to know is on the Internet and that a "Google" search will tell us everything. But "Google" can not replace the type collections; it cannot replace the actual specimen, and without on ogin research it cannot update information that is critical to invasive species decision making.

Friday, September 19, 2008

In my historic town of Upper Marlboro, near the Patuxent river in Maryland, my county has decided to place a waste transfer station one mile from the river next to wetlands in the middle of endangered species surrounded by park land recently acquired to preserve the river eco-system over looked by a restored colonial house. This they do while claiming the tile of environmental legislators. You can find my rants which are diverting me from my invasive species issues for the time being at my other web log:

The incredible hubris that thinks this is a good idea is at least partially based upon the short term benefits of pretending that natural areas are simply blank canvasses upon which we need to impose development for our common short term good. It is the development version of the current mind set in our financial markets: who needs regulation as long as many are getting wealthy. Of course when things go wrong then the very same people immediately demand that the rest of pay up so that they may continue to take risks with out bounds.

Saturday, September 13, 2008

Invasive Inconvenience Wicked Definitions

September finds the invasive species discussion in full swing. As befits a wicked inconvenience, interested parties present their views, each in the bubble of indignation and subjective attack. We are expected to find a simple linear answer bereft of complexity and choose sides. The challenge of invasive species conversation prevents nuanced discussion. As a wicked problem, parties to the controversy are required to be right, in their particular world view, and then actually begin to have a discussion.

On September 7th, 2008 feralkevin stated for the record that there “There are no objective definitions of “invasive” and “native.” I would have liked him to cite a source or sources for this claim, but none was forthcoming. Specifically, I wonder what an objective definition might be. How many people must be polled in order to decide a definition is objective, and is this how the scientific system is supposed to work? I rather thought that the idea was to posit a hypothesis and then subject the idea to multiple tests of the proposition until such a time as the theory is accepted by a majority of researchers, a majority being a rather broad aggregation of current work by specialists in their fields.

In the discussions of environmental issues, issues which are a wicked inconvenience, the choice of words is critical. However because of the complexity of the issue at hand, and because there are multiple stakeholders at the table, the precise meaning behind words is often assumed or presumed. Worse, words that have a scientific definition are most often appropriated out of context but the political discussion resulting in confusion to the end users who come to the table with preconceived notions based on internal definitions of the same terms. There is in some sense a hierarchy to terminology with fuzzy parameters; I propose that the Heisenberg Principle, as I understand it, most likely applies to definitions:

One can either KNOW the meaning in the limited specialized context of the moment, or one can understand the context surrounding the word or term actually having a precise definition at hand One cannot have both a precise meaning and a general context. If one is working in general context to broad audiences the definition of the word or term will be in motion and imprecise subject to immediate and constant redefinition.

Feralkevin states that “Modern ecology tells us that pretty much all ecosystems are recently evolved aggregates.” A friend wrote to me noting that “They (ecosystems) might be recent in terms of geological times scales, but so are humans. What (are) a couple of million years, compared to 4.5 billion years? However, systems are not "recent" in terms of human time scales and predate humans by thousands to tens of thousands of years. Invasions drive loss of biodiversity. Isolation drives speciation (sic) and biodiversity. Darwin's finches being prime examples. Islands (isolated areas) generate and contain the highest numbers of endemic species.”

I have written several times about the problem of scale in landscape and invasive species decision matrices. The blinders of the immediate obscure the choices of tomorrow. For better or worse we tend, for self preservation reasons, to focus on today and now in an endless series of small/fast dynamic choices, making our decisions without considering larger scale implications of the large/slow variety.

As I struggle to keep up with the author’s theses, Feralkevin writes that “… many people say it (Elaeagnus umbellate) dozen’t “belong” because it wasn’t there until very recently. What usually is not be considered here is the drastic changes the land has endured very recently. Now that the land has been catastrophically destroyed basically, does E. umbellata with its soil healing ability and massive edible abundance, really not “belong”?"

A contrarian view is presented in an interesting work on the subject by Cora Ann Johnston. “Habitat disturbance through anthropogenic development often leads to invasion by exotic species. While studies have examined the influence of non-native species on the breeding habitat of birds, little researched has looked at the importance of plant community composition change on the food resources available at stopover habitat used by migrating species. In order to examine the influence of land-use change, and especially species invasion, I analyzed the plant cover across forest, edge, and rural remnant habitat and assayed nutritional content of fruits from several common species of native and exotic plants in fruit in mid November near Falmouth, Massachusetts. I found that disturbed (edge and rural) habitat had higher total cover and exotic plant cover, while forests contained only native species. Assays of protein, carbohydrate, and lipid indicated that exotic fruits were sugary; natives were fatty. Studies of the preferred nutritional content used by resident and migratory birds indicate that only the lipid-rich natives are a suitable food source for migrating species. I also found that most fruiting plants were exotic, suggesting that they may fruit too late to be available during migration. Together, the availability and nutrition of exotic fruits suggests that they are not a suitable food replacement for migratory bird species. While this has conservation implications, further studies need to be completed in order to better analyze periods of bird migration and fruit production of all plant species in the area.”[i]

How can we square these two propositions? It seems that in the light of the present discussion we are faced with two seemingly opposed world views. The first strongly suggests that we are to mold the environment as we go adapting as we need in a series of best short term return option decisions, while the second thinks that we should attempt to integrate natural systems as best as we can with the knowledge of eco system services so that we can maximize the long term benefits as we understand them today. The former view seeks adaptation to a continuing use of natural systems a an infinite resource, the latter views a resource of systems which is finite and diminishing.

Feralkevin thinks that “Modern ecology tells us that pretty much all ecosystems are recently evolved aggregates. All species invade other places and have their ecosystems invaded. This is the drive of biological diversity. We don’t like certain species for certain reasons, some rational and others not. This points to the understanding that an “invasive” species is not a scientific phenomenon, but a cultural one.” This ties nicely with the next e-mail of the day, “Friendly Invaders” This article appeared in print on September 9, 2008, on page F1 of the New York edition.[ii] Mr. Zimmer writes, “But in a paper published in August in The Proceedings of the National Academy of Sciences, Dov Sax, an ecologist at Brown University, and Steven D. Gaines, a marine biologist at the University of California, Santa Barbara, point out that the invasion has not led to a mass extinction of native plants. The number of documented extinctions of native New Zealand plant species is a grand total of three.”

This rather interesting statement is off-set by an entry on the Wikipedia site: “The ecosystems of Lake Victoria and its surroundings have been badly affected by human influence. In 1954, the Nile perch (Lates niloticus) was first introduced into the lake's ecosystem in an attempt to improve fishery yields of the lake. Introduction efforts intensified during the very early-1960s. The species was present in small numbers until the early to mid-1980s, when it underwent a massive population expansion and came to dominate the fish community and ecology of the world's largest tropical lake. Also introduced was the Nile tilapia (Oreochromis niloticus), now an important food fish for local consumption. The Nile perch (Lates niloticus) proved ecologically and socioeconomically devastating. Together with pollution born of deforestation and overpopulation (of both people and domestic animals), the Nile perch has brought about a massive transformation in the lake's ecosystem and to the disappearance of hundreds of endemic haplochromine cichlid species. Many of these are now presumed to be entirely extinct. A number of other species are extinct in the wild, with populations being maintained in zoos and aquaria, e.g. as part of the Association of Zoos and Aquarium's Species Survival Plan for these species. Some species which were extirpated from Lake Victoria itself, are known to survive in nearby smaller so-called satellite lakes, such as Lake Kyoga, Lake Edward and Lake Albert.
Also vanished from Lake Victoria is one of two native species of tilapia (another kind of cichlid fish), the Singidia tilapia or ngege (Oreochromis esculentus). The ngege is superior in taste and texture to Nile tilapia, but it does not grow as fast or as large and produces fewer young. Ngege and some representatives of haplochromine diversity survive in minute swamp ponds and lakes that dot the Lake Victoria Basin. The initial good returns on Nile perch catches, at their peak delivering export revenues of several hundred million dollars a year, have diminished dramatically due to poor enforcement of fisheries regulations. The proceeds from Nile perch sales remain an important economic engine in the region, but the resulting wealth is very poorly distributed and the overall balance sheet on the Nile perch introduction to Lake Victoria is well into the red[citation needed] despite the enormous value of the perch landings as an export commodity.


Add to this conversation climate change and the addition of CO2 and the complexities quickly overwhelm the casual observer.

[i] Implications of land-use change on food resource availability for birds : Cora Ann Johnston, Hampshire College, Amherst, MA 01002, 18 December 2006, Advisor: Chris Neil, Collaborator: Brook Brouwer.
[ii] CARL ZIMMER, Published: September 8, 2008.


Tuesday, September 02, 2008

National Invasive Species Committee meeting: send in your ideas

The National Invasive Species Council Advisory Committee (ISAC) will be meeting in Baltimore, Maryland, November 18th and 19th, 2008. This is a public meeting and all are welcomed to attend. The National Invasive Species Council is co-chaired by the Secretaries of the Interior, Agriculture and Commerce, and its members include the Secretaries of State, Defense, Transportation, Treasury, Health and Human Services, and Homeland Security and the Administrators of the U.S. Environmental Protection Administration, the National Air and Space Administration, U.S. Agency for International Development and the U.S. Trade Representative.

The Invasive Species Advisory Committee is made up of 31 individuals representing a broad range of stakeholders including scientific, conservation, agriculture, State and Tribal governments and industry organizations that are impacted by invasive species.

This will be the first meeting of ISAC Class V which will include an orientation for new ISAC members. It is also the first ISAC meeting since the approval on August 1, 2008 of the 2008-2012 National Invasive Species Management Plan (2008 Plan). This Plan sets out the overall blueprint for NISC member departments and agencies in dealing with the issues of invasive species for the next five years. The 2008 Plan includes a number of items in which nonfederal partners are likely to play a role as well as a number of items for which NISC as an entity or NISC staff are the lead or an important participant. ISAC provides advice and input to the NISC federal agencies and it is important that ISAC study the 2008 Plan and identify priority objectives or action items that ISAC would work on to provide advice and input to NISC agencies to help in the implementation of the 2008 Plan. Therefore the theme of the November 2008 meeting is how ISAC can best provide input and advice to assist NISC in the implementation of the 2008 Plan, including setting out priorities and specific recommendations as well as referring work to the relevant NISC/ISAC Subcommittees. This will be an over-arching theme and associated or separate items may also be considered at the meeting. Under this theme, issues associated with invasive species in the context of bio-fuels (a prevention item) will be one topic that will be addressed as recommended at the last ISAC meeting in Alaska, May 2008.

As a member of ISAC, but acting personally, I am taking this opportunity to ask you to send to me any topics or ideas which you feel the federal advisory committee should take under consideration. Please send ideas, comments and/or suggestions to IPETRUS@MSN.COM

Members of the Fifth Convening of the Invasive Species Advisory Committee
Name - Affiliation
Peter Alpert, Ph.D. - University of Massachusetts
Nancy Balcom - Connecticut Sea Grant
Leslie Cahill - American Seed Trade Association
Timothy Carlson - Tamarisk Coalition
Earl Chilton, II, Ph.D. - Texas Parks and Wildlife Department
Janet Clark - Montana State University
Joseph DiTomaso, Ph.D. - University of California, Davis
Otto Doering, III, Ph.D. - Purdue University
Susan Ellis - California Department of Fish and Game
Miles Falck - Great Lakes Indian Fish and Wildlife Commission
Christopher Fisher - Colville Confederated Tribes
Amy Frankmann - Michigan Nursery and Landscape Association

Ann Gibbs - Maine Department of Agriculture(Representing National Plant Board)
Catherine L. Hazlewood, Esq. - The Nature Conservancy
Lisa Ka’aihue - Prince William Sound Regional Citizens’ Advisory Council
John Kennedy - Wyoming Game and Fish Department(Representing the Association of Fish and Wildlife Agencies)

Robert McMahon - University of Texas at Arlington
Kathy Metcalf - Chamber of Shipping of America
Edward L. Mills, Ph.D. - Cornell University
Jamie K. Reaser, Ph.D. - Pet Industry Joint Advisory Council
Steven Jay Sanford - New York Department of Environmental Conservation
Jeffrey D. Schardt - Florida Department of Environment Protection
Celia Smith, Ph.D. - University of Hawaii
David E. Starling - Aqueterinary Services, P.C.
Nathan Stone, Ph.D. - University of Arkansas at Pine Bluff
Douglas W. Tallamy, Ph.D. - University of Delaware
John Peter Thompson - The Behnke Nurseries Company
Jennifer Vollmer, Ph.D. - BASF Corporation
Damon E. Waitt, Ph.D. - Lady Bird Johnson Wildflower Center University of Texas at Austin
Robert H. Wiltshire - Center for Aquatic Nuisance Species(Representing the Federation of Fly Fishers)
Kenneth Zimmerman - Lone Tree Cattle Company

Monday, August 11, 2008

Invasive species redefined

Definitions are a challenge in the area of invasive species. What do we mean by “native”? What exactly is an exotic species? Even the term invasive is problematic; is poison ivy invasive, are white-tailed deer invasive? I had conversation about invasive species with a reluctant audience of one. He struggled to change the topic to the Olympics, but I held on. I pointed out the damage that his beautifully manicured beds of English ivy caused the local environment. I told him that his Japanese wisteria enveloped by his ‘Queen Elizabeth’ climbing rose was a threat to biological diversity in the local eco-system. He pointed to a well- designed perennial border surrounding a circle of brick with a few benches, and told me that he was moving the native weeds to the back forty and replacing them with low maintenance grass, which would not harbor so many bugs and reptiles.

The conversation was not going well, when he suddenly said that he understood the issue. An example of an invasive species causing harm would be humans like the Russians invading Georgia…and when they got to the South Carolina border he would be there ready with the Maryland National Guard holding the Old Line. So much work so little time.

Tuesday, August 05, 2008

Invasive species; endangered species

Invasive species issues are a wicked problem, a wicked inconvenience. Because the issues of invasiveness and invasion are complex existing on many levels of understanding simultaneously, the invasive species which through domination of the landscape create monocultures that become in turn biological deserts; invasive species which alter the structure of soils creating pathways for secondary invasion; invasive species which provide fantastic exotic colors and forms while removing habitat for indigenous species, replacing food sources or shelter, all of these challenges compete for our attention and are part of any effort to define the problem. Adding to the problem of understanding is the concept of scale. We can see immediate change up close, but as we increase the time span or the geographic expanse, we quickly loose our sense of place. And, then, because invasive species issues are a type of wicked problem, they influence other wicked problems or are influenced by them.

Invasive species are a major threat to endangered species. Invasive species are the reverse of the endangered species problem. When the two meet, easily held ideas begin to melt. Lauren Morello, ClimateWire reporter, writes that “the Quino checkerspot butterfly is being squeezed out of the real estate market.” Because of habitat loss and climate change as well as development, she continues, the butterfly’s habitat is severely constrained, the species endangered to the point perhaps of no return. The solution may be to move the native species to a cooler location,

Ah, the tangled webs we weave when we begin down this path. Ms. Morello notes that “…it could turn an endangered plant or animal into an invasive one, wreaking havoc on the new ecosystem's native plants, animals and insects.” Trying to balance all the needs of all the stakeholders comes to the fore ground. What is native? Do we let one species decline to protect a “natural” eco-system?

“Keeping the distance between the old and new habitats short is also key, she (Camille Parmesan, a global change biologist) said. Since many invasive species problems can be tied to continent-to continent hops by plants and animals, scientists should limit their targets to within 100 to 500 miles of a species' original home.” The assumption that non indigenous species from North America are less harmful than non native species from Europe opens yet another avenue of contention.

The problem is not that the goals are bad but that they are at some level mutually exclusive. Saving an endangered species by moving it seems simple enough. Moving enough of the eco-system to ensure that it continues to survive, sounds like an exercise in horticulture. Defining what native means in the context of climate change is daunting. And all of this within the discussion of what is an invasive species. How do we know what will happen when an organism is moved. How can we tell the effect of the new habitat on the introduced species, or the impact on the eco-system by the new species?

Of course there is the non option of doing nothing. Or the option of realizing that everything we do has the potential effect of the flapping of the wings of a butterfly in Mongolia.

reprint of article send to me by email from a colleague

"Like many Southern California natives, the Quino checkerspot butterfly is being squeezed out of the real estate market. The insect once ranged from Ventura County, Calif., down to Baja California, Mexico. But in recent years, its habitat has declined by nearly 80 percent, thanks to increasing development in San Diego and Los Angeles and rising temperatures along the Mexican border. Now, threatened by climate change and hemmed in by development, the endangered butterfly's best hope may lie with a once-unthinkable solution: allowing humans to move the species to a new habitat in a cooler climate. The idea, called "assistedmigration" or "assisted colonization," gives many conservation biologists pause. Such a move could fail, further reducing a dwindling species' numbers. Or it could turn an endangered plant or animal into an invasive one, wreaking havoc on the new ecosystem's native plants, animals and insects.

Yet, in the face of rising temperatures and changing weather patterns, many scientists say it's an idea they can no longer afford to reject. "I would talk to people about it at conservation meetings 10 years ago, and it was totally, completelydismissed," said Camille Parmesan, a global change biologist at the University of Texas-Austin. "Five years ago, people were mumbling about it. Two years ago, papers started coming out."

Now Parmesan and colleagues in Australia and England have authored the first framework to help biologists and policymakers decide when such a radical move may be appropriate. Their paper was published yesterday in the journal Science. "I think it's a great paper," said Jessica Hellmann, a biology professor at the University of Notre Dame who is organizing a new scientific working group to examine the concept. "I think it's important for people to talk about [assisted migration]. This is an issue that is not going to sit around and wait very long for us to figure it all out."

'A difficult pill to swallow'
To Parmesan, the seemingly radical response to climate change is a natural outgrowth of her large-scale studies of global warming's effects on hundreds of plant and animal species and more detailed research of butterflies. "When you start doing that work, you realize that climate change is having a huge impact on where species live," she said. "A lot of biologists still think it's into the future. They don't realize we've already got enormous numbers of observed changes."

Still, supporters of assisted migration couch their comments in caveats, viewing it as an unpalatable, but increasingly likely, option. "When I first heard it come up, it was discussed almost with revulsion that we would really tamper so heavily with ecosystems," said John Kostyack, director of wildlife conservation and global warming programs at the National Wildlife Federation. "It's a very difficult pill to swallow to think we would be involved with that level of intensive management. It's a major paradigm shift."
“Now,” he said, "people are thinking of it as a realistic option that has to be considered -- recognizing again that it's a last resort."

May be the only survival route for some species Bob Davison, a senior scientist with Defenders of Wildlife, agreed. "I think it is something that probably -- in very limited circumstances -- we should be considering," he said. "It might be the only way for corals or some other species." But it would require moving forward with extreme caution, experts said. To avoid the possibility of creating a new invasive species, scientists should only consider moving species whose habits are well-documented, Parmesan said. "For a lot of species, we just don't know enough, and we wouldn't consider them good candidates. Really, it's a tradeoff between how much you know about the species you want to move and how degraded the area is where you want to move them." Keeping the distance between the old and new habitats short is also key, she said. Since many invasive species problems can be tied to continent-to continent hops by plants and animals, scientists should limit their targets to within 100 to 500 miles of a species' original home.

In the case of the Quino checkerspot butterfly, the risk of creating a new invasive species is low, she said. "It doesn't compete with other species," Parmesan said. "It's not aggressive and it doesn't defend nectar sources. It eats a very common plant and never does much harm to plant populations. And when you put it somewhere, it tends to stay there." The butterfly's poor mobility is one reason human intervention may be necessary, she added. Other species that may be good candidates for assisted migration include those that are highly mobile but find their paths blocked by cities or agricultural fields. "Even the best disperser is not able to go 300 miles past large urban areas," Parmesan said. "The Midwest is a real barrier for a lot of southern
species that are trying to move north."

But even after clearing the scientific hurdles, political difficulties may remain. "My biggest fear is that people will misunderstand and think about this as a solution for climate change biodiversity problems -- but it's not," said Hellmann, the Notre Dame biologist. "It could never be a solution for a lot of species. So greenhouse-gas reduction should still be the No. 1 priority." Kassie Siegel, director of the climate program at the Center for Biological Diversity, said she also is wary of how policymakers may interpret the idea. "I think the big danger here is that we allow really reasonable, farsighted thinking about assisted migration to be allowed as an excuse by decision-makers to avoid mitigation measures," she said. "The devil's in the details."

There is also the risk that assisted migration of a species could simply fail. "The trouble is that the climate hasn't stabilized at its new level yet," Parmesan said. "It's a continually moving target. Until we get our atmospheric levels of greenhouse gases stabilized, which we're way far away from, we don't know what the new climate is going to be." Without a worldwide plan in place to drastically cut emissions, it's impossible to pinpoint where climate change might stop, Hellmann added. "We often talk about 2050 or 2100 like we'll be done [with climate change] or have a new climate by then," she said. "But we don't know when climate
change will be ending." In the end, though, climate change may force scientists' hands, said Kostyack.
"If you are reduced to functional extinction, to captive breeding program with no hope of returning a species to its original range, [migrating a species] seems to be a better option than having it go extinct."
Moving a 160-year-old species north Despite those concerns, at least one group outside mainstream science is already moving forward with plans to revive a species by moving it to a new home beyond its natural habitat.

The Torreya Guardians, a loosely defined group of "citizen-scientists," horticulturists and ecologists, are planning to plant 31 seedlings of an endangered evergreen -- Torreya taxifolia, also known as the "stinking cedar" -- in North Carolina later this month. It's part of a last-ditch effort to save the Torreya. Ravaged by warming temperatures and fungal diseases in recent decades, the 160 million-year-old species
is now found in pockets of land along Florida's Apalachicola River and in southern Georgia. Of the thousand or so wild Torreya taxifolia trees in the United States, just one is healthy enough to produce seeds, scientists believe. With that in mind, the Torreya Guardians are busily harvesting seeds from Torreya trees living in nurseries and private gardens, such as those at the Biltmore estate in Asheville, N.C. They're convinced that moving the species to a cooler climate offers the best hope for its continued survival. "We realized when it comes to plants, if you have access to a private seed stock and someone's property or horticultural nursery, you can take those seeds and plant them on your property, wherever you live," said Torreya Guardians member Connie Barlow, explaining the group's strategy, which allows it to operate outside the bounds of the federal Endangered Species Act."

7/18/08 2:10 PM Endangered species: As climate warms, scientists consider a new Noah's ark -- 07/18/2008 --
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Wednesday, July 09, 2008

Alaskan pike: wicked species inconveniently invade

As a member of the National Invasive Species Advisory Committee (ISAC), I was privileged to attend a meeting in Alaska in May 2008. As part of a spectacular tour, ISAC went to Lake Cheney to learn about pike invasions, which, in the words of an article by S.J. Komarnitsky, published in The Anchorage Daily News, July 8, 2008,“has wiped out a popular rainbow trout and landlocked-salmon fishery.” We found that the usual flexible fuzzy understanding of key words such as native, alien, exotic, and invasive were in full play.
Invasive species are by federal definition in the United States alien, exotic, non indigenous species. For those who do not live in the world of definitions or do not think clearly about what the words mean, a fish that is native (to Alaska) could therefore not be invasive, and so transporting it from one eco-system, with in Alaska to another surely could not be harmful at least in the world of invasive species issues. The appearance of the pike outside of its natural range strongly suggests that a well-meaning fisherman, a member of one of the many invasive species stakeholder groups, attempted to increase the sport fishing at the local lake by bringing “native” Alaskan pike to Anchorage….Alaska.
The wicked inconvenience of invasive species issues, the complexities inherent in any effort to find clear, concise and inarguable positions or solutions (Saturday, September 29, 2007; Invasive Species Conundrum: A Wicked Inconvenience & Sunday, February 18, 2007 Invasive Species; Wicked Inconvenience: part two ) comes forth vividly in the article. The reporter writes that “Besides Cheney Lake, the state hopes to use rotenone in Arc Lake near Soldotna and in a series of ponds in Yakutat known as the "Village" or "Post Office" ponds.” For some stakeholders, this is a perfectly reasonable response to a major problem and threat, for although the loss of a few fishing holes is not in themselves a critical threat, the proximity to major tributaries and salmon runs most certain is. The writer notes that “At all three sites, biologists are worried about the pike spreading to nearby salmon streams. Arc Lake is only two miles from Soldotna Creek, which feeds into the Kenai River. Cheney Lake is just a hop and a skip from Chester Creek.”
Because invasive species issues are engaged by multiple stakeholders whose interests and definitions may be or become at cross purposes, improbable obstacles arise quite quickly. In an effort to protect the environment, which is what the several interested parties want by virtue of their interest, one group would use chemical control to return the pre invasion status quo, while a second equally determined to protect the environment states that there can be no chemical control. “(A)n resident who also sits on the council, however, said he would oppose any use of the chemical. He has read concerns on the Internet about rotenone and is distrustful of using any chemical that kills an animal no matter the assurances about its safety. ‘I'm of the opinion that the use of any kind of chemical or pesticide has side effects,’ he said.”
So here at a small lake in great Alaska, the forces of humanity decide to wage battle. Do we use any resource starting with the least harmful and working our way up the chain (IPM) until we get control, or do we allow the damaged eco-system to evolve on its own and do nothing? Do we apply chemicals to increase crop production to feed the world, or do we share our crops with other hungry species? How much diversity versus how many human lives? And at a higher level of complexity, do we act now in short term interest and deal with long term effects somehow, or do we suffer now for the potential good of the eco-system down he road. Ultimately, some could seem to be asking if the world would be better off without Homo sapiens.
I note with some interest, that plants and insects use chemicals many times to create their own “safe” special place in the world. The chemical under consideration the author points out is rotenone, “… a naturally occurring chemical that comes from a member of the bean family. According to a manual on rotenone distributed by the American Fisheries Society, a professional society for fisheries scientists, a 160-pound person would have to drink 23,000 gallons of water treated at 0.25 milligrams of rotenone per liter of water (the highest allowable treatment rate for fish management) at one sitting to receive a lethal dose.”
It seems strange that a black walnut, some beans and other species can use chemicals to help insure survival, but humanity should not. That said the practice of integrated pest management should always be a core part of the decision and execution process. Start with the least harmful and the least amount and work one’s way up to a tolerable level; begin with an assumption that working with the local eco-system is a strong basis for survival.

Tuesday, July 01, 2008

Yet Another Invasive Species: Killer Fungus

Invasive species and gardeners do not always get along. Gardeners from time to time are passionate in their right to plant any species for the glory and betterment of the design. The concepts of invasive species detection, control and eradication cause a great amount of angst in the world of horticulture as the purveyors feel that their right to complete freedom of choice is being potentially denied by restrictive lists and suggestions.

On the other hand, the same gardeners with equal passion demand the interdiction and elimination of pests and pathogens from their gardens, and are among the first to recognize the invasive, pervasive and destructive nature of foreign, alien and exotic insect and disease species. It is worthwhile to remember that invasive species are not limited to horticultural specimen plants, but to all taxa, and are part of a interconnected web of cause and effect.

The surge of invasive species is a consequence of climate change, as well as a result of the fragmenting and loss of biological diversity in eco-systems and habitats.

Tree-Killing Fungus Officially Named by Scientists Asheville,NC --

The USDA Forest Service Southern Research Station (SRS) today announced that an SRS scientist and other researchers have officially named the fungus responsible for killing redbay and other trees in the coastal plains of northeastern Florida, Georgia, and South Carolina.
Lead author and Iowa State University Plant Pathologist Tom Harrington, co-author and SRS Plant Pathologist Stephen Fraedrich, and Azerbaijan National Academy of Sciences Researcher D.N. Aghayeva unveiled the name, Raffaelea lauricola, in an article published in the April-June 2008 issue of Mycotaxon, the international journal of fungal taxonomy and nomenclature.

“Until now, the fungus was known as ‘the laurel wilt pathogen’ because of the devastating disease it causes in redbay trees and other laurel species like sassafras and avocado trees in the Southeast,” said Fraedrich, based in Athens, GA. “Now arborists, foresters, researchers, and regulatory officials have a formal, scientific name and description of the fungus, as well as a detailed explanation of how the pathogen compares to similar fungi.”

Raffaelea lauricola is one of many species of fungi carried by ambrosia beetles, a group of highly specialized wood-boring insects that feed on symbiotic fungi, which they carry from tree to tree in specialized sacs. The beetles feed on their own special ambrosia fungi, much as the Greek gods were believed to exist on their "ambrosia." R. lauricola is the principle ambrosia fungus of an invasive species from Asia, the redbay ambrosia beetle. R. lauricola is the only known tree pathogen among the ambrosia fungi and differs from other Raffaelea species in its DNA sequence and spore sizes. The fungus also grows faster than similar fungi.
Ambrosia beetles introduce the fungus into redbay or other laurel tree species by burrowing into the trees and laying eggs. The fungus serves as a food source for beetle larvae. The pathogen moves through a tree’s vessels causing a vascular wilt disease similar to Dutch elm disease.

In an April 3 press release, SRS announced the first description of the fungus and its association with the redbay ambrosia beetle and laurel wilt. The press release, posted online at, provides more information about the fungus and the threat it poses to the laurel family. []

Monday, June 30, 2008

Invasive Plant Research and Partnership

This is the report from a gathering of organizations and stakeholders which I helped bring together in March of 2008.
I wish to thank Dr. Phyllis Johnson, USDA ARS, retired, for coming up with the idea of a meeting of the minds, and Dr. Chris Dionigi, NISC, for making this meeting possible.
Invasive Plant Research and Partnerships with Ornamental Horticulture and Natural Resource Management Workshop Report

Sponsored by:
U. S. National Arboretum
Beltsville Agricultural Research Center
The Nature Conservancy
The American Nursery and Landscape Association
National Invasive Species Council

Suggested Citation: Invasive Plant Research and Partnerships with Ornamental Horticulture and Natural Resource Management Workshop Report. May 2008. Workshop sponsored by U. S. National Arboretum, USDA Beltsville Agricultural Research Center, The Nature Conservancy, The American Nursery and Landscape Association, National Invasive Species Council, and Invasive Species Advisory Committee. Held March 3 and 4, 2008, at the U.S. National Arboretum, Washington, D.C. 30pp.
Executive Summary…………………………………………… 3
1. Introduction………………………………………………… 6
2. General Consensus Points…………………………………. 7
3. Research Prioritization Criteria and Planning…………… 8
4. Research Focus Areas………………………………………. 9
5. General Strategic Research Planning Needs……………… 10
6. Process and Institutional Recommendations……………… 11

7. Issues Outside the Scope of the Workshop……………….. 12

Appendix 1: Workshop Participants………………………… 13

Appendix 2: Meeting Agenda………………………………… 17

Appendix 3: Invasive Species Definition Clarification…...… 18

Appendix 4: On-line Resources……………………………… 30

Executive Summary
Many non-native plants are important components of gardens, farms, orchards, and landscapes. However, some non-native plants escape cultivation and cause economic and environmental harm. These “invasive plants[1]” complicate efforts to sustain our natural areas and cultivated landscapes. The environmental conservation community, federal resource managers, the horticulture industry, and others all seek to avoid the introduction and spread of invasive plants. Development of new plant cultivars that retain valuable horticultural characteristics and also exhibit “non-invasive” attributes, e.g., sterility, provide enhanced planting options and reduce the likelihood of undesired spread. However, the degree that traits are exhibited by plants can vary among cultivars, and there are no agreed upon scientifically demonstrable standards for “sterile,” “hardy,” and “non-invasive” traits. In addition, plants and their environments are dynamic. Rising carbon dioxide concentrations, atmospheric deposition of nitrogen, habitat fragmentation, and other global-scale processes impact plant invasions within the decadal periods envisioned by current landscape and natural resource management plans.

On March 3 and 4, 2008, a workshop was held at the U.S. National Arboretum. Representatives of the horticulture industry, natural resource managers, environmental conservation groups, researchers, and others identified strategic knowledge gaps and priorities for ornamental plant breeding and natural area protection research and related issues. The focus was on the USDA’s U.S. National Arboretum’s and the Beltsville Agricultural Research Center (BARC) research agendas. Research by other agencies and institutions was also discussed.
General Consensus Points:
1) Industry and natural resource conservation stakeholder groups represented were in consensus concerning the importance of coordination and avoiding the introduction and spread of invasive plants.

2) Partnerships and communication among industry representatives, natural resource managers, and research administrators are critical to the success of research programs.

3) Terminology can contribute to confusion. It is important to clarify terms initially, e.g., “invasive species,” during discussions.

4) Stakeholders, i.e., the horticulture industry and conservation groups, have not agreed upon standards (i.e., adequate levels of expression) for attributes such as “sterility,” and “non-invasiveness” in plant selections and cultivars. However, the relative effectiveness of the underlying genetic and/or physiological mechanisms that produce sterility in a cultivar provides a level of assurance of that cultivar’s anticipated performance in the field.

5) Decisions concerning codes of conduct, regulations, and planting recommendations should be based on “sound science.” Although specific scientific standards were not identified in this workshop, examples of the application of sound science principles were provided.

6) Systematics[2] is a critical limiting factor. There are critical shortages of trained systematics experts and gaps in the U.S. systematics research and collections infrastructure. For example, currently there is no comprehensive inventory of the cultivated plants in North America[3].

7) A critical limiting factor is shared access to reliable information. There is no centralized, searchable data source of credible, geographically-referenced information on the behavior of species, cultivars, and hybrids of cultivated plants in the field, i.e., information concerning their undesired spread, if any. Data exists in dispersed sources. Their reliability is difficult to determine and coverage is incomplete.

8) Finding solutions to complex problems requires research efforts at that are sustained over long periods at levels that are commensurate with the value of the resources a stake. Resources are a critical limitation.

Priority should be given to research projects that are:
1) Integrated - Establish or enhance strategic multi-sector partnerships that consider the integrated needs of a full range of stakeholders, such as conservationists, industry, and consumers;
2) Strategic - Build strategic “infrastructure elements,” avoid duplication, and employ the most efficient and up-to-date methodologies and approaches;
3) Important - Address urgent problems and/or problems where research would contribute to substantial positive economic and environmental benefits, and of;
4) Broad Application – Provide a sustained stream of new products and solutions that meet stakeholder and consumer needs in applications that range from highly cultivated landscapes to natural areas.
Research Focus Areas:
1) Non-invasive Alternatives:
a. enhanced techniques for reducing plant reproduction/spread, such as obligate (true)
sterility and lack of spontaneous vegetative reproduction, including specific gene and
chromosome (ploidy) manipulation;
b. enhanced methods for the scientific evaluation of new plants for invasiveness
(screening); and
c. develop scientific standards for non-invasive attributes, e.g., sterility.

Research Focus Areas Cont.:
2) Quantifying Harm/Benefits and Avoiding Negative Impacts:
a. determine the impacts (if any) of native plant cultivars on indigenous native plant
b. develop methods for objectively evaluating the harm/benefits of invasive plants on
native plant and animal populations and ecosystem services, such as effects on water
quality and wildlife habitat;
c. develop scientific methods for the evaluation of post-cultivation persistence/spread of
species, cultivars, and hybrids of cultivated plants;
d. determine how site-specific factors (i.e. soils, climate, and disturbance) influence plant
behavior in the environment and the harm/benefit caused by cultivars;
e. determine how(if) gene flow and pathogens influence plants’ invasiveness and impacts;
f. develop scientific objective methods for estimating (ranking) the invasive potential of
cultivars and hybrids of cultivated plants;
g. enhance methods for the detection, evaluation, and response to new invasions
(Early Detection and Rapid Response, i.e., EDRR); and
h. develop ways to identify invasive taxa (e.g. genetic markers) for use by field
personnel when evaluating plants found at sites.
1. Introduction
Many non-native plants are important components of gardens, farms, orchards, and landscapes. However, some non-native plants escape cultivation, spread, persist, exclude other species, and cause other forms of economic and environmental harm. Other plants arrive unintentionally as hitchhikers on materials, equipment, and by other pathways of introduction. These invasive plants[4] are harmful to natural areas and cultivated landscapes. They are ongoing problems for conservationists, gardeners, and public-sector resource managers. They complicate the shared challenge of sustaining our natural areas and cultivated landscapes. It can be difficult to correctly identify plants, especially closely related taxa in the field. Cultivars may not be readily discernible, even by experts. Additionally, certain hybrids can exhibit invasive characteristics that are not known in parent populations. The public, the environmental conservation community, and the horticulture and landscaping industry all seek to avoid the introduction and spread of invasive plants and protect both natural areas and cultivated landscapes.

Invasive species cross jurisdictional boundaries and require a coordinated multi-sector response. Executive Order 13112 created the National Invasive Species Council (NISC) to coordinate federal invasive species actions. NISC is co-chaired by the Secretaries of the Interior, Agriculture, and Commerce and in total contains thirteen members. The Invasive Species Advisory Committee (ISAC) is chartered under the Federal Advisory Committee Act to provide non-federal stakeholder advice to NISC. The coordination of research is an important aspect of NISC’s work, and critical to solving invasive species problems. Scientific information is also needed to provide a sound underpinning for self-regulation of invasive plants and for federal or state regulations.
Research is advancing our capacity to address invasive species issues. However, significant technical challenges and knowledge gaps remain. Currently, there is no comprehensive inventory of the plants in cultivation in North America. Many plant characteristics that contribute to “invasiveness” have been identified, but the underlying genetic, physiological, and ecological processes and interactions are poorly understood. Both plants and their environments are dynamic. The potential impacts of global-scale processes, particularly rising atmospheric carbon dioxide concentrations and nitrogen deposition, increase the invasiveness of some plants. These dynamics are increasingly a factor in invasive species policy and management decisions.
Scientific advances in molecular genetics, plant breeding, systematics, ecology, and other fields offer great promise and are very active areas of research. The development of new plant cultivars that retain valuable horticultural characteristics and also exhibit important “non-invasive” traits, such as stable sterility and a lack of spontaneous vegetative reproduction, provide enhanced options for new and replacement plantings, while reducing the likelihood of escape from cultivation. However, there are no agreed upon scientifically demonstrable standards for traits such as “sterile,” “hardy,” “non-invasive,” and “non-persistent” that would provide performance targets for plant breeding research and cultivar selection and evaluation efforts.

The U. S. National Arboretum maintains a 446 acre facility in Washington, DC that welcomes over 500,000 visitors a year. Additionally, the National Arboretum conducts nearly two-thirds of all the USDA-ARS’s research in ornamental horticulture. This $12.8 million per year research and education facility has made over 675 official ornamental/horticultural plant releases. The National Arboretum is part of USDA’s Agricultural Research Service’s Beltsville Agricultural Research Center (BARC). The nearby 6900-acre BARC research facility is the largest agricultural research facility in the U.S. The National Arboretum and BARC are uniquely qualified to provide scientific information that is needed to solve many of the problems concerning the invasiveness of ornamental plants.

On March 3 and 4, 2008, U. S. National Arboretum, BARC, The Nature Conservancy, The American Nursery and Landscape Association, Invasive Species Advisory Committee (ISAC) and NISC sponsored a workshop at the U.S. National Arboretum in Washington DC. A total of thirty-five representatives of the commercial horticulture industry, ISAC, natural resource managers, NISC, state government officials, environmental conservation groups, researchers, and other constituencies from across the U.S participated (see Appendix 1). Participants included: Dr. Peter Raven the President of the Missouri Botanical Garden and a Trustee of the National Geographic Society, Deputy Assistant Secretary of the Interior Paul Hoffman, and the Executive Director of NISC, Lori Williams. Facilitators were provided by the Department of the Interior and NISC.

Purpose and Scope of the Workshop:
This workshop was convened to explore whether a consensus could be reached among representatives of the commercial horticulture industry, natural resource managers, environmental conservation groups, and researchers concerning knowledge gaps and research priorities for ornamental plant breeding and testing and natural area protection. An emphasis was placed on discussion rather than formal presentations (see Appendix 2). Objectives were to identify specific focus research areas and criteria for prioritization of projects. The focus was on BARC and the U.S. National Arboretum’s research agendas. However, other research partner organizations were included and recommendations outside the scope of this meeting were also offered.

2. General Consensus Points
Participants represented a diverse range of stakeholders, interest groups, subject discipline areas, sectors, and regions. However, consensus was reached on several issues.

Participants agreed that invasive species are critical problems for both highly cultivated landscapes and for natural-resource conservation. The need for federal interdepartmental coordination and for input from the full range of stakeholders was identified as critical to the shared goal of avoiding the introduction and spread of invasive plants. Stakeholders have important resources and expertise, and they can provide specialized opportunities to test new methods and cultivars. However, no single agency or group can provide all of the perspectives and resources needed. Partnerships and communication among industry, natural-resource conservation, and research institutions were indentified as critical to the success of research programs. Invasive-species research requires new partnerships with institutions and constituencies in addition to those with long records of involvement with the USDA.

A key factor contributing to inefficient communication is “terminology.” What is meant by terms such as “sterile, hardy, non-invasive, weedy, and invasive species” varies among individuals. Some terms such as, “invasive species,” “variety” and “noxious” have definitions that are established Executive Order 13112, the Plant Variety Protection Act, and the Plant Protection Act. Additionally, supportive information concerning the definition of “invasive species” has been developed by ISAC (see Appendix 3). Certain definitions are appropriate for regulations others maybe appropriate for public information and educational campaigns. The use of definitions without explanation and clarification can lead to confusion and unintended interpretations of statements, documents and meeting outcomes. Participants agreed that it is important to clarify terms used during discussions and recognize the potential for miscommunication.

Development of new plant cultivars that retain valuable horticultural characteristics and also exhibit important “non-invasive” attributes, such as stable sexual sterility and lack of spontaneous vegetative reproduction, provide enhanced options for new and replacement plantings, while reducing the likelihood of escape from cultivation and undesired spread. However, the degree and stability (i.e. robustness) of those traits can vary among cultivars, over time and across regions. Various genetic and/or physiological mechanisms lead to different degrees of sterility. Stakeholders, such as the horticulture industry and conservation groups, have not agreed upon standards (i.e., adequate levels of expression) for attributes such as “sterility,” and “non-invasiveness” in plant selections and cultivars. However, the relative strength and stability of the underlying genetic mechanism(s) used to produce a trait provides an indication of a cultivar’s anticipated performance in the field. For example, cultivars that have reinforcing (redundant) mechanisms of sterility exhibit more robust sterility. Enhanced methods for the scientific evaluation of new plants for invasiveness (i.e., screening) would augment the field evaluation of plant selections.
Participants agreed that decisions concerning development of codes of conduct, regulations, and planting recommendations should be based on “sound science.” Although specific scientific standards were not determined in this workshop, examples of the application of sound science principles were provided, e.g., the California Horticultural Invasive Prevention partnership (CAL-HIP) project concerning Pampasgrass and Jubatagrass [Pampasgrass and Jubatagrass Threaten California Coastal Habitats. 1999. J. M. DiTomaso, E. Healy, C. E. Bell, J. Drewitz, and A. Tschohl, Leaflet #99-1. See Appendix 4].
A critical limiting factor is authoritative identifications of plant specimens and related systematics information. Currently, there is no single source of systematic information that researchers and others can use to find what cultivars are currently or have been grown in North America. Work toward a comprehensive cultivated flora of North America was presented. This flora will be very large and require on-going revision. It may use a “Wiki-type” open review and editing structure. A comprehensive cultivated flora would have several applications. For example, to obtain a Certificate of Protection under the Plant Variety Protection Act, plant breeders must demonstrate that a proposed new plant variety is “new and distinct” from all other varieties. Specifically, a cultivated flora would help plant breeders protect a new “non-invasive cultivar” by indicating what other varieties are in cultivation. Research advances could help plant breeders differentiate non-invasive cultivars from others by demonstrating the removal or suppression of the invasive traits. Additionally, the performance of a particular cultivar in the field, such as its spread, viable seed production, vegetative reproduction, hybridization, and other characteristics related to invasiveness could be entered into the database and be subject to review and revision. Currently, there is no centralized searchable data source of credible, geographically referenced information concerning the performance of cultivars. Information, such as undesired spread or persistence, may be available from dispersed sources. However, information about specific cultivars is often lacking, and the reliability of available data is difficult to determine.

Some cultivars may not be readily discernible, even by experts. There is a critical shortage of trained systematics experts. In the past, programs such as the National Science Foundation’s Partnerships for Enhancing Expertise in Taxonomy (PEET) provided support for the training of systematics and systematics research. However, new faculty positions, graduate fellowships, and research support for systematics are declining. Systematics laboratories and collections are also in decline. There is a need for enhanced methods to identify invasive taxa (e.g. genetic markers) that can be used by field personnel and others.

Finding solutions to complex problems requires sustained research that maintains the continuity of programs over time and is coordinated among locations and across subject discipline areas. Lapse in research support can undermine years of effort. Additionally, research funding should be at levels that are commensurate with the size of the resources at stake. The nursery industry is estimated to be about a $4.65 Billion industry (U.S. Department of Agriculture, National Agricultural Statistics Service page 9.) In 2005, U.S. grower sales receipts for annual and perennial bedding and gardening plants alone totaled about $2.6 billion (Floriculture and Nursery Crops Yearbook. Market and Trade Economics Division, Economic Research Service, U.S. Department of Agriculture, June 2006, FLO-2006.). Sustained support for research at levels that are commensurate with stakeholder needs was identified as critical gap.

3. Research Prioritization Criteria and Planning
Participants suggested several criteria for prioritizing research projects and suggestions for planning research.
Criteria for establishing priorities:
1. A priority should be placed upon research that not only solves a specific problem but also increases overall research capacities.
2. Certain projects exploit similarities among taxa and allow the rapid propagation of technical advances to other areas of application. Others offer a sustainable source of new products and other advances over time. Projects that offer broad and/or sustained applications should be given priority.
3. Certain problems are urgent. Research can expedite the detection of emerging problems and increase our ability to respond quickly while problems are localized and by that prevent more extensive harm. Priority should then be given to projects that increase our abilities to proactively avoid problems and take timely action.
4. Certain problems result in large economic costs and/or environmental impacts and research may provide large benefits compared to investments of time and research costs. Projects with a potential for extensive benefits should be given priority.
5. Advances in molecular genetics, plant breeding, systematics, and other fields may expedite research, and also make possible new solutions. Efforts that utilize “cutting edge” methodologies and advance the overall technical capacity should be given priority.
6. Research efforts that augment and complement other efforts but not duplicate them should be given priority.
Suggestions for planning research:
1. In addition to cultivated landscapes, planning should consider a range of potential applications, such as how specific research might be integrated with environmental restoration projects, biomass and bio-fuels production, overseas development programs, and natural area management.
2. The potential impact and relevancy of research should be considered so that there is a balance between long-standing problems and emerging “new” issues. Additionally, a balance between economic and ecological benefits should be sought.
3. Focus should be on researchable targets where it is anticipated that significant advances will be available within a five to twenty-year period. Timeline planning should anticipate partnerships needed to transfer basic research advances to the private sector for further development. The needs of consumers and those that supply consumer needs should be considered early in the planning process.
4. No single agency or group can provide all of the perspectives and resources needed. A project’s potential to establish and foster strategic partnerships should be evaluated.

5. Integrated planning should focus on enhancing overall capacities and infrastructure. Areas of strength, unique capacities, specific resources, roles and responsibilities within partnerships, and strategic gaps should be identified and then evaluated among research cooperators.
4. Research Focus Areas
Participants identified two focus areas for research. In addition, specific examples of research topics were suggested within the two focus areas.

1) The development of non-invasive cultivars that serve as alternatives to currently available invasive plants.

The development of enhanced techniques for manipulating plant reproduction/spread was identified as a way to develop new plant cultivars that retain valuable horticultural characteristics and also exhibit important “non-invasive” attributes. The manipulation of genes involved in sexual and vegetative reproduction, alteration of chromosome (ploidy) number, production of single sex populations and sterile hybrids were identified as approaches to developing obligate (true) sterility. Molecular techniques such as “knockout genes” and “epigenetics” or gene silencing may also be useful.

It is important to note that asexual and vegetative mechanisms can be important means of reproduction and spread. All mechanisms of reproduction and spread must be identified and addressed. Physiological and genetic information is needed to develop relative rankings of the invasive potential for cultivars and the scientific evaluation of new plants species and cultivars.

Gene flow or introgression of genes within populations could result in a reversion of the progeny of some plants to invasiveness. Cultivars that have very stable and/or reinforcing (redundant) mechanisms of sterility (and lack spontaneous vegetative reproduction) typically exhibit greater levels of sterility, and are less likely to regain an ability to reproduce than other cultivars. The type(s) of sterility bred into plant selections yielding new cultivars could be indicated at points of sale to facilitate purchaser choice.

2) Improved quantification and prediction of the current and potential harm and/or benefit of species and cultivars and avoiding negative impacts.

There is a need for improved methods to determine the benefits and harm (if any) caused by non-native plant cultivars and their underlying genetic, physiological, and ecological mechanisms. For example, various cultivars may harbor or inhibit pathogens or differ in their value as wildlife food. They may provide differing levels of ecosystem services, such as preventing soil erosion. The competiveness of cultivars with native plants may also vary among cultivars and across environmental gradients. In addition to the plants themselves, the potential for gene flow from cultivars of native species to indigenous (or local) native populations could impact plant and animal communities. Understanding of the underlying genetic, physiological, and ecological mechanisms that produce specific benefits or undesirable traits would guide further development of plant selections and evaluation of cultivars.

Interactions with physical conditions and the “human environment” can be critical to a cultivar’s performance. Cultivars may differ in their responses to soils, fire, flooding, precipitation, climate change, light quality and quantity, and both natural and human-induced disturbance. The need for objective quantitative methods to determine “invasiveness” e.g., post-cultivation persistence, spread, and harm (if any) of cultivars across environmental gradients and a range of environmental applications is needed.

The combination of early detection, rapid assessment, and rapid response (EDRR) can prevent larger negative impacts from invasive species. Improved GIS-based methods for finding invasive populations that are large enough to detect, but localized enough to contain and eradicate are needed. Systematic analysis and access to up-to-date and accurate inventory and mapping data are needed for the timely assessment of suspected invasions and prediction of spread and impacts. Improved methods for the containment and eradication of localized invasive species populations are also needed.

5. General Strategic Research Planning Needs
Central to strategic planning is the clear identification and articulation the actual or “root” problem to be solved by the research. Focus should remain on what objective is actually to be accomplished and differentiate between objectives and strategies towards an objective. For example, is the objective to remove invasive populations or it is to reduce their impacts? Is it to promote the recovery of native species or maintain ecosystem services? Is the prevention of invasive species range expansions the objective or a strategy towards a larger objective? Seemingly subtle differences can lead to very different outcomes. Research recommendations should identify priority problems rather than “desired” or predetermined solutions. This allows researchers to bring the latest advances and strategies to bear on problems and allow for unanticipated or “creative” solutions, rather than trying to achieve a specific solution. Close coordination with research partners and on-going stakeholder review helps ensure that research remains directed at core problems.

Many ornamental plants are long-lived species and are planted across wide regions. Research planning should consider large-scale and long-term factors, such as climate change, habitat fragmentation, and changes in land use. To facilitate this, there is a need for global climate modeling as related to invasive species threats and interactions. Information, such as current and potential ranges, rates of spread, and predicted effects of increased nitrogen and carbon dioxide availability could guide research efforts. Additionally, information on plant systematics and mapping, cultivar sterility, persistence, growth, and spread within and among regions, vegetative growth and interactions with native plant populations, and plant and site-specific factors that contribute to invasiveness is needed. In some cases, invasive species may be symptomatic of both global-scale processes and localized disturbances. These underlying factors must be addressed to achieve invasive species objectives.

6. Process and Institutional Recommendations
Adoption of products and practices depends in part upon consumer choice. A better understanding of consumer attitudes towards invasive species, why and how they make planting choices, and how best to market alternatives can help guide research. Enhanced agency information staff participation is needed in research planning rather than just “after the fact.”
Scientifically-sound reinforcing messages must be provided to consumers directly and by those that they rely upon for information. “Awareness messages” should be coupled with “action” or “what I can do” messages. Information and technology transfer staff members can facilitate the transfer of research results to professional educators, Master Gardeners, horticulture and landscape professionals, and Land Grant University personnel. However, in addition to these “traditional contacts,” information staff members should develop contacts with conservation organizations and other stakeholders so that they are aware of ARS-generated developments.

Academics have access to scientific publications in peer-reviewed journals and presentations at scientific society meetings. These communicate effectively within the academic community, but they are not sufficient for consumer education needs. Communicating research findings to consumers is also required.

Much of the information produced is supported by federally agencies or grants. These data are in the public domain. There are extensive data sources, such as the USDA’s Natural Resource Conservation Service’s PLANTS database and those at the USDA’s National Agricultural Library. However, there is no centralized repository of searchable geographically-linked data. Data are available from dispersed sources, but reliability of those data is difficult to determine. Although data are often lacking, conducting a comprehensive analysis of gaps is also difficult.

Interdepartmental and interagency review of research contributes to improved quality assurance of the products and practices developed. Cross-agency coordination with Department of the Interior, Animal Plant Health Inspection Service, and other agencies increases ARS’s service to those action agencies and departments.

Research, especially with long-lived plant species, may require long timeframes and have both a high risk of failure and a high impact. The evaluation and compensation of researchers involved in “high risk” and long-term research needs to differ from that used to evaluate researchers involved in shorter-cycle projects.

7. Issues Outside the Scope of the Workshop
Research questions concerning biofuel crops, forage crops, and large-scale post-fire restoration plantings were identified as being similar to those discussed at this workshop that was focused upon ornamental plants. In addition, determining the most effective forms and methods for public communication of important invasive-species concepts, e.g., what is an invasive species and what actions should an individual take, were identified as important to the overall success of programs.
Appendix 1: Workshop Participants
Present at the Workshop:
Elenor Altman Adkins Arboretum
Gordon Brown U.S. Department of the Interior
Chip Cameron Facilitator
Steve Clemants Brooklyn Botanic Gardens
Brian E. Corr Ball Horticultural Company
Hilda Diaz-Soltero U.S. Department of Agriculture
Chris Dionigi NISC Staff
Thomas Elias USDA U.S. National Arboretum
Amy Frankmann Michigan Nursery and Landscape Association and ISAC
Dave Fujino California Center for Urban Horticulture
Susan Goodwin Facilitator
Robert Griesbach USDA Agricultural Research Service
John Hammond USDA U.S. National Arboretum
Nadine Hiers USDA U.S. National Arboretum
Paul Hoffman U.S. Department of the Interior
Carol Holko Maryland Department of Agriculture
Kate Howe The Nature Conservancy
Gary Knosher Midwest Groundcovers, LLC
Faith Kuehn Delaware, Plant Protection and Weed Management Section
Kerrie Kyde Maryland Department of Natural Resources
Wayne Mezitt Weston Nurseries
Richard Olsen USDA U.S. National Arboretum
Margaret Pooler USDA U.S. National Arboretum
John Randall The Nature Conservancy
Tom Ranney North Carolina State University
Peter Raven Missouri Botanical Garden
Craig Regelbrugge American Nursery & Landscape Association
Robert E. Schutzki Michigan State University
Joe Spence USDA Animal Health Inspection Service
Carol Spurrier U.S. Bureau of Land Management
Catherine Hazlewood The Nature Conservancy and ISAC
Marc Teffeau American Nursery & Landscape Association
John Peter Thompson The Behnke Nurseries Company and ISAC
Mary Travaglini The Nature Conservancy
Lee Van Wychen Weed Science Societies of America
Valerie Vartanian The Nature Conservancy
Alan Whittemore USDA U.S. National Arboretum
Mark Widrlechner USDA North Central Regional Plant Introduction Station
Lori Williams NISC Staff
Lewis Ziska USDA Agricultural Research Service

Appendix 2:
Workshop on Invasive Plant Research and Partnerships with Ornamental Horticulture and Natural Resource Management

Monday, March 3, Objective – Discuss and identify the issues
Discussion Lead
8:30 - 9:00
Arrive & sign in

9:00 - 9:10
Welcome from National Arboretum

National Arboretum: T. Elias
9:10 - 10:00
- Introductions around the table
- Groundrules
- Agenda review

10:00 - 10:50
Overview of work on Invasive Species
- National Invasive Species Council (NISC)
- Invasive Species Advisory Committee (ISAC)
- USDA: Agricultural Research Service (ARS)
- Questions & comments
NISC: P. Hoffman
NISC/ISAC: L. Williams
ARS: J. Spence

10:50 - 11:10

11:10 - 11:50
How will outcomes of meeting be used?
- Research priorities & national program planning
- Transfer of technology & research results to industry & resource managers
- Questions & comments
ARS National Program Staff: G. Wisler
Office of Technology Transfer: R. Griesbach

Monday, March 3, Cont.
11:50 - 1:00

1:00 - 3:00
Panel Discussion:
- Background & importance of issue from perspectives of industry, conservation community, & Federal government
- Questions & comments
ANLA: M. Teffeau C.Regelbrugge
TNC: J. Randall V. Vartanian
Federal: H. Diaz-Soltero, G. Brown
3:00 - 3:15

3:15 - 3:45
Climate Change & Cultivars
- Climate change impacts on planting & resources management decisions
- Questions & comments
BARC: L. Ziska
3:45 - 4:15
Systematics – What plants are here now?
- What do we know & need to know about cultivated plants in North America
- Questions & comments
Missouri Botanical: P. Raven
4:15 - 4:30
Wrap up & prepare for second day
- Overnight assignments? Things to think about?
- Plus/Delta (what went well today & what should we change for tomorrow)

Tuesday, March 4, 2008, Objective – Identify researchable targets
Discussion Lead
8:30 - 9:00
Arrive & check in

9:00 - 9:30
Recap from Day 1 & Agenda overview of Day 2
9:30 - 10:30
What abilities do we have now? In the next 5-10 years?
- Current systematics, bredding & selection programs & methods
- Emerging technologies, new methods & opportunities, e.g. genetic sterility.
- Questions & comments
ARS: R. Olsen

10:30 - 10:45

10:45 - 11:45
Small Group Discussions- Develop initial list of Researchable Targets (problems to be solved)
- Criteria for prioritizing targets (e.g. costs/impacts/importance of the problem, technical feasibility of solutions, strategic partnerships availability, duplication avoidance (is it already being done?), & etc.)
Each group will identify a facilitator & recorder
11:45 - 12:15
Small groups report back to full group
Facilitators will record on flip charts
12:15 - 1:15

1:15 - 3:30
Identify Priority Researchable Targets: Link priority problems & potential approaches/opportunities.
- Criteria for identifying & prioritizing researchable targets
-Application of criteria to researchable targets
- Identify potential candidate targets
- Identify resource gaps, barriers and opportunities to complete target research & strategize about how to fill gaps (ie. leveraging resources through partnerships, other opportunities…)

Full group discussion
3:30 - 4:15
Identify roles, timetable & next steps
4:15 - 4:30
Wrap up & Plus/Delta

Appendix 3: Invasive Species Definition Clarification and Guidance White Paper

Invasive Species Definition Clarification and Guidance White Paper
Submitted by the Definitions Subcommittee of the
Invasive Species Advisory Committee (ISAC)
Weeds As Examples
Weeds provide good examples to clarify what is meant by an invasive species because most people have a concept of what constitutes a “weed.”
Invasion can be thought of as a process that in our example, a plant must go through to become a successful, yet harmful invader. Several barriers must be overcome for a plant to be considered an invasive weed. Invasive weeds are invasive species.
Large-scale geographical barriers
First, a geographical barrier first must be overcome, which often occurs as a mountain range, ocean, or similar physical barrier to movement of seeds and other reproductive plant parts. Plants that overcome geographical barriers are known as alien plants or alien species. Alien plants are non-native plants and alien species are non-native species. Therefore, non-native plants are those that occur outside their natural range boundaries, and this most often is mediated by humans either deliberately or unintentionally.
Survival barriers
The second set of obstacles that a non-native plant must overcome is barriers to germination and survival in its new location. These typically are environmental barriers such as adequate moisture availability to allow successful germination and survival of seedlings that will continue to grow to maturity. Other physical barriers might be soil pH, nutrient availability, or competition for resources from neighboring plants.

Dispersal barriers

Established alien plants next must overcome barriers to dispersal if they are to continue on the process to become invasive weeds. Or simply put, they must spread from their site of establishment. For example, an established, terrestrial, alien plant that reproduces only by seed would be considered an invasive plant if it spreads from its establishment site more than 100 yards in about 5 years. Or, if an established, terrestrial, alien plant reproduces vegetatively, it would be considered an invasive plant if it spread more than 6 yards in 3 years from its establishment site. However, this movement or spread alone does not make this invasive plant a harmful invader or invasive weed.


To be labeled an invasive weed or harmful invader, the invasive plant must cause negative environmental effects and these may have associated negative economic effects. Just as importantly, however, the overall negative effects caused by an invasive plant must outweigh any beneficial effects to warrant designation as an invasive weed or invasive species. For example, we do not mean smooth brome, we do mean water hyacinth; we do not mean ?, we do mean zebra mussels.
Approved by ISAC April 27, 2006
Preamble: Executive Order 13112 – defines an invasive species as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.” In the Executive Summary of the National Invasive Species Management Plan (NISMP) the term invasive species is further clarified and defined as “a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health.” To provide guidance for the development and implementation of the NISMP, the National Invasive Species Council (NISC) and the Invasive Species Advisory Committee (ISAC) adopted a set of principles outlined in Appendix 6 of the NISMP. Guiding Principle #1 provides additional context for defining the term invasive species and states “many alien species are non-invasive and support human livelihoods or a preferred quality of life.” However, some alien species (non-native will be used in this white paper because it is more descriptive than alien), for example West Nile virus, are considered invasive and undesirable by virtually everyone. Other non-native species are not as easily characterized. For example, some non-native species are considered harmful, and therefore, invasive by some sectors of our society while others consider them beneficial. This discontinuity is reflective of the different value systems operating in our free society, and contributes to the complexity of defining the term invasive species.
NISC is engaged in evaluating and updating the 2001 NISMP and is developing comments for a revised action plan as required by the EO 13112. While there have been numerous attempts to clarify the term invasive species, there continues to be uncertainty concerning the use and perceived meaning of the term, and consequently over the prospective scope of actions proposed in the NISMP. Options related to private property use, pet ownership, agriculture, horticulture, and aquaculture enterprises may be affected depending upon the definition, use, and policy implications of the term.
Weeds As Examples (continued)
Establishment barriers
The third obstacle that a non-native plant must overcome to be considered an invasive weed, is to form a population that is self-sustaining and does not need re-introduction to maintain a population base such that it continues to
survive and thrive in its new environment. Once this occurs, this population of non-native plants is considered to be established. Environmental barriers to survival and establishment are similar.
Dispersal and spread barriers
Established non-native plants must overcome barriers to dispersal and spread from their site of establishment to be considered invasive plants. Additionally, the rate of spread must be relatively fast. However, this movement or spread alone does not necessarily make this non-native plant an invasive weed or invasive species.
Harm and impact
Finally, a plant is deemed to be invasive if it causes negative environmental, economic, or human health effects, which outweigh any beneficial effects. For example, yellow starthistle is a source of nectar for bee producers. But the displacement of native and other desirable plant species caused by yellow starthistle leads to dramatically decreased forage for wildlife and livestock, which severely disrupts the profitability of associated businesses. These negative effects greatly overshadow the positive effects and thus, define harm caused by yellow starthistle and explain why it is considered an invasive species.

In particular, the desire to consider a non-native species as ‘invasive’ may trigger a risk/benefit assessment process to determine whether regulatory action is warranted. All these uncertainties have stood and could continue to stand in the way of progress in actions and policy development to prevent new invasions and manage existing invasive species. While it is not the purpose of this white paper to define a risk/benefit assessment process, development of such a process must be open and efficient to minimize the uncertainties.

This white paper is intended to provide a non-regulatory policy interpretation of the term invasive species by identifying what is meant, and just as important, what is not meant by the term. ISAC recognizes that biological and ecological definitions will not precisely apply to regulatory definitions. We believe, however, that our clarification will apply to all taxa of invasive species in all habitats and furthermore, our explanation will be functional and acceptable to most stakeholders. ISAC simply wants to clarify what is meant and what is not meant by the term invasive species in the technical sense and to provide insight into those areas where societal judgments will be necessary to implement effective public policy.
The utility of our clarification should be in education, conflict resolution, and efficiency in the planning, prevention, control/eradication, and management of invasive species.
ISAC recommends that NISC adopt the clarifications presented in this white paper to foster progress for invasive species management in the United States.

An invasive species is a non-native species whose introduction does or is likely to cause economic or environmental harm or harm to human, animal, or plant health. The National Invasive Species Management Plan indicates that NISC will focus on non-native organisms known to cause or likely to cause negative impacts and that do not provide an equivalent or greater benefit to society. In the technical sense, the term ‘invasion’ simply denotes the uncontrolled or unintended spread of an organism outside its native range with no specific reference about the environmental or economic consequences of such spread or their relationships to possible societal benefits. However, the policy context and subsequent management decisions necessitate narrowing what is meant and what is not meant by the term invasive species. Essentially, we are clarifying what is meant and not meant by “causing harm” by comparing negative effects caused by a non-native organism to its potential societal benefits.
Perception to Cause Harm
Complications concerning the concept of invasive species arise from differing human values and perspectives. Differing perceptions of the relative harm caused or benefit gained by a particular organism are influenced by different values and management goals. If invasive species did not cause harm, we would not be nearly as concerned. Perceptions of relative benefit and harm also may change as new knowledge is acquired, or as human values or management goals change.
For a non-native organism to be considered an invasive species in the policy context, the negative effects that the organism causes or is likely to cause are deemed to outweigh any beneficial effects. Many non-native introductions provide benefits to society and even among species that technically meet the definition of invasive, societal benefits may greatly exceed any negative effects (for example crops and livestock raised for food). However, in some cases any positive effects are clearly overshadowed by negative effects, and this is the concept of causing harm. For example, water hyacinth has been popular in outdoor aquatic gardens but its escape to natural areas where its populations have expanded to completely cover lakes and rivers has devastated water bodies and the life they support, especially in the southeastern U.S. And, there are some organisms, such as West Nile virus, that provide almost no benefits to society at all. Such organisms constitute a small fraction of non-native species, but as a consequence of their ability to spread and establish populations outside their native ranges, they can be disastrous for the natural environment, the economies it supports, and/or public health. Because invasive species management is difficult and often very expensive, these worst offenders are the most obvious and best targets for policy attention and management.
The negative impact to a native species caused by an invasive species might trigger additional negative interactions for other associated native species; i.e., there could be direct and indirect effects. For example, an invasive weed that is undesirable as a food source may outcompete and displace native grasses and broadleaf plants. These displaced native grasses and broadleaf plants may have been primary forage for animals, which subsequently would be displaced to a new location or have their populations reduced because the weed invasion decreased the availability of food in their native plant and animal community. However, negative effects are not always characterized by a cascade of impacts realized throughout the environment. For example, simple displacement of an endangered species by a non-native species might alone provide sufficient justification to consider the non-native organism an invasive species.
What We Do Not Mean, What We Do Mean, and the “Gray” Area
Native and Non-native Species
Invasive species are species not native to the ecosystem being considered. Canada geese are native to North America and most of their populations migrate annually. However, in some locations in the U.S. (e.g. suburban Maryland; the Front Range of Colorado) introduced, non-migratory populations of Canada Geese are causing problems – such as fouling lawns, sidewalks, grass parks, and similar areas. While non-migratory populations can cause problems, they are not considered an invasive species because they are native. Additionally, Canada geese are of significant financial value to many local economies through waterfowl hunting and simple enjoyment. Mute swans, however, are invasive. Mute swans are native to Europe and Asia but were introduced into North America where their populations have increased dramatically. They compete directly with native waterfowl for habitat, displacing them, and that is why they are considered an invasive species. Whitetail deer populations have increased dramatically in the northeastern U.S. and are problems in farms, yards, and natural areas because they consume plants valued by humans; but are not invasive because they are native. Nutria, on the other hand, are another classic example of an invasive species. Nutria are native to South America but were introduced into North America where their populations have soared. Nutria compete directly with native muskrats, beavers, and other similar native species for habitat; often causing the displacement of these native species.
Feral Populations
It is also essential to recognize that invasive species are not those under human control or domestication; that is, invasive species are not those that humans depend upon for economic security, maintaining a desirable quality of life, or survival. However, the essential test is that populations of these species must be under control. Escaped or feral populations of formerly domesticated plants and animals would be considered invasive species if all the concepts and conditions are met as outlined in “Weeds Are Examples.” Cereal rye being produced on a farm in Kansas is considered very desirable, but feral rye on the breaks of the Poudre River in Colorado would be considered an invasive species because it is displacing native plants and the native animal communities they support. Domesticated goats on a farm in Texas are considered highly desirable, but feral goats in Haleakala National Park on Maui are considered an invasive species. Feral goats have severely overgrazed areas and eliminated native Hawaiian plants, which were never adapted to grazing. Areas denuded by feral goats have led to increased soil erosion.
A Biogeographical Context
An invasive species may be invasive in one part of the country, but not in another. A biogeographical context must be included when assessing whether a non-native species should be considered an invasive species. Lake trout are highly desirable in the Great Lakes where they are native, but are considered an invasive species in Yellowstone Lake. They compete with native cutthroat trout for habitat, which decreases their populations. Atlantic saltmarsh cordgrass is an essential component of east coast salt marshes, but is highly invasive on the west coast where it covers mudflats and displaces native estuarine plants and the community of animals they support, including huge flocks of migrating waterfowl. Kentucky bluegrass would be considered an invasive species in Rocky Mountain National Park in Colorado, but considered non-invasive a mere 60 miles away at a golf course in Denver. English ivy is considered a good ground cover species in the Great Plains and Midwest, but is a highly invasive weed in the forests of the Pacific Northwest and Eastern U.S. where it outcompetes native plants and displaces the associated animal communities.
The “Gray” Area
There are obvious examples of invasive species such as snakehead fish, yellow starthistle, or Phytophthora ramorum (the organism that causes sudden oak death); and there are obvious examples of species that are not invasive, namely native plants and animals. There are, however, non-native organisms for which it will be difficult to make a determination and these should be subject to assessment. Whether these non-native organisms will be considered invasive species will depend upon human values. For example, European honeybees are cultured to produce honey and pollination services, and even though they form wild populations in many parts of the country and occasionally create problems by building hives in the walls of homes or can be a human health problem for individuals that are highly allergic to their sting, most would not consider them an invasive species because they produce a desired food product.
Another gray area example would be native termites v. Formosan termites. No one wants termites in their homes but only Formosan termites would be considered an invasive species because they are non-native. Smooth brome also serves as another gray area example. It was imported from Russia in the 1890s for forage and was widely planted. It clearly has escaped cultivation and can be found in many natural areas particularly in the western U.S. but in most situations, smooth brome would not be considered an invasive species because of its forage value for wildlife and livestock.
Chinese or Oriental clematis serves as another gray area example. Chinese clematis (virgin’s bower, orange peel) is a popular ornamental that has been planted worldwide. However, it has escaped cultivation in several western states where its populations can spread, particularly in shrubland, on riverbanks, sand depressions, along roadsides, in gullies, and along riparian forests in hot dry valleys, deserts, and semi-desert areas. Escaped populations of Chinese clematis occur in Idaho, Nevada, Utah, New Mexico, and Colorado but so far, it is considered an invasive species only in Colorado where it has spread dramatically from its site of introduction and displaced native plant species.
Environmental Harm
We use environmental harm to mean biologically significant decreases in native species populations, alterations to plant and animal communities or to ecological processes that native species and other desirable plants and animals and humans depend on for survival. Environmental harm may be a result of direct effects of invasive species, leading to biologically significant decreases in native species populations.
Examples of direct effects on native species include preying and feeding on them, causing or vectoring diseases, preventing them from reproducing or killing their young, out-competing them for food, nutrients, light, nest sites or other vital resources, or hybridizing with them so frequently that within a few generations, few if any truly native individuals remain. Environmental harm includes decreases in populations of Federally Listed Threatened and Endangered Species, other rare or uncommon species and even in populations of otherwise common native species. For example, over three billion individual American chestnut trees were found in U.S. forests before the invasive chestnut blight arrived and virtually eliminated them. Environmental harm also can be the result of an indirect effect of invasive species, such as the decreases in native waterfowl populations that may result when an invasive wetland plant decreases the abundance of native plants and thus, decreases seeds and other food that they provide and that the waterfowl depend upon.
Environmental harm also includes significant changes in ecological processes, sometimes across entire regions, which result in conditions that native species and even entire plant and animal communities cannot tolerate. For example, some non-native plants can change the frequency and intensity of wildfires, or alter the hydrology of rivers, streams, lakes and wetlands and that is why they are considered invasive species. Others can significantly alter erosion rates. For example, trapping far more wind-blown sand than native dune species, or holding far less soil than native grassland species following rainstorms. Some invasive plants and micro-organisms can alter soil chemistry across large areas, significantly altering soil pH or soil nutrient availability. Environmental harm also includes significant changes in the composition and even the structure of native plant and animal communities. For example, the invasive tree Melaleuca quinquinervia, can spread into and take over marshes in Florida’s Everglades, changing them from open grassy marshes to closed canopy swamp-forests.
Environmental harm may also cause or be associated with economic losses and damage to human, plant and animal health. For example invasions by fire promoting grasses that alter entire plant and animal communities eliminating or sharply reducing populations of many native plant and animal species, can also lead to large increases in fire-fighting costs and sharp decreases in forage for livestock. West Nile virus is a well known human health problem caused by a non-native virus which is commonly carried by mosquitoes. West Nile Virus also kills many native bird species, causing drastic reduction in populations for some species including crows and jays.
Additional Examples of Impacts Caused by Invasive Species
Specific examples of the harm caused by invasive species are useful to further clarify the definition. The following list of examples is not meant to be comprehensive, but offers further explanation:
Impacts to Human Health
Respiratory infections: The outbreak of West Nile virus in the U.S. began in the Northeast in 1999 and has since spread throughout the country. Infections in humans may result in a flu-like illness and in some cases death. This outbreak has caused illness in thousands of citizens, increased medical costs for affected persons, and decreased productivity due to absence from work. West Nile virus also has affected horses and has caused widespread mortality in native birds (U.S. Centers for Disease Control, 2006).
Poisonous plants: Exposure to the sap of Tree-of-heaven/Chinese sumac tree has caused inflammation of the heart muscle (myocarditis) in workers charged to clear infested areas. Afflicted personnel experienced fever/chills, chest pain that radiated down both arms, and shortness of breath. Exposure occurred when sap from tree-of-heaven contacted broken skin. Such exposure has caused hospitalization, medical expense, and lost productivity due to absence from work (Bisognano et al. 2005).
Impacts to Natural Resources
Declines in wildlife habitat and timber availability: Chestnut blight is a disease of American chestnut caused by a non-native fungal pathogen that was introduced into eastern North America around 1910. The disease eliminated the American chestnut from eastern deciduous forests thereby decreasing timber harvests and wildlife that depended upon the American chestnut for habitat (USDA-APHIS/FS 2000).
European gypsy moth defoliates trees on millions of acres of northeastern and mid-western forests. It currently is found in 19 states causing an estimated $3.9 billion in tree losses and also decreased wildlife habitat (USDA-APHIS/FS 2000).
Decreased soil stabilization and interrupted forest succession: White pine blister rust is a disease of white pine species caused by the non-native fungal pathogen Cronartium ribicola. It was introduced into eastern North America around 1900 and western North America in 1920. It spread rapidly, killing off native white, whitebark, and limber pines, whose seeds are an important food source for birds, rodents and bears. Elimination of these trees caused by this pathogen alters forest ecosystems, eliminates wildlife forage, and decreases the soil stabilization effects of these trees, snowmelt regulation, and forest succession (Krakowski et al. 2003).
Changes in wildfire frequency and intensity: Cheatgrass decreases the interval between the occurrences of wildfires in the Great Basin region from once every 70 to 100 years to every 3 to 5 years because it forms dense stands of fine fuel annually. The decrease in interval between wildlfires causes increased risk to human life and property and also places at risk established communities of plants and animals that we consider desirable (Knapp 1996; Pimentel et al. 2000; USFWS 2003; Whisenant 1990).
Excessive use of resources: Tamarisk in the desert southwest use more than twice as much water annually as all the cities in southern California, which places this invasive weed in direct competition with humans for the most limiting resource in the southwestern U.S. (Friederici 1995; Johnson 1986).
Suppressors: Russian knapweed exudes toxins from its tissues that inhibit the growth of surrounding plants or eliminates them. Desirable plant communities are placed at risk from Russian knapweed invasion, which may result in decreased numbers of wildlife species or livestock that the invaded land otherwise could support. Russian knapweed also is very toxic to horses (Stevens 1986; Young et al. 1970a and 1970b).
Decreased carrying capacity for wildlife and livestock: Expansion of leafy spurge, yellow starthistle, or other unpalatable invasive weeds displace desirable forage plants and may allow fewer grazing animals to survive in infested areas (DiTomaso 2001; Lym and Messersmith 1985; Lym and Kirby 1987).
Impacts to Recreational Opportunities and Other Human Values
Decreased property values: Asian longhorned beetles first appeared in New York in 1996 and in Chicago in 1998. Larvae burrow into trees causing girdling of stems and branches, dieback of the crown, and can kill an entire tree. It infests many different tree species in the U.S. and is a threat to urban and rural forests (Cavey et al. 1998).
Emerald ash borers were first detected in the U.S. in 2002. They currently are found in Michigan, Ohio, and Indiana. Emerald ash borer larvae tunnel under bark of ash trees and could eliminate ash as a street, shade, and forest tree throughout the U.S. Estimated replacement cost in six Michigan counties is $11 billion and an additional $2 million in lost nursery sales (Chornesky et al. 2005).
Dutch elm disease was first introduced into the U.S. in 1927 and occurs in most states. Dutch elm disease has killed more than 60% of elms in urban settings and decreased the value of urban and suburban properties (Brasier and Buck 2001).
Spotted knapweed and leafy spurge expansion in the western U.S. have displaced desirable forage plants thereby decreasing the value and sales price of grazingland in the western U.S. (Maddox 1979; Weiser 1998).
Eurasian watermilfoil was introduced into the U.S in the 1940s and has since spread throughout much of the country. This submersed aquatic plant can form dense mats at the water surface limiting access, recreation, and aesthetics and thus, has decreased the values of shoreline properties in New Hampshire, the Midwest and elsewhere (Halstead et al. 2003).
Decreased sport fishing opportunities: Whirling disease is caused by a parasite (Myxobolus cerebralis) that most likely originated in Europe. It was first observed in the U.S. in 1958. The parasite attacks the soft cartilage of young trout causing spinal deformities and causes the fish to exhibit erratic tail-chasing behavior. Heavily infected young trout can die from Whirling disease and even if they recover, they remain carriers of the parasite. All species of trout and salmon may be susceptible and angling and the businesses supported by trout and salmon fishing may be at risk if this disease continues to spread (Aquatic Nuisance Species Task Force et al. 2005; Colorado Division of Wildlife 2006).
Smallmouth bass fishing in Lake Erie was closed during bass mating because of round goby predation of nests. Fishing was closed because male smallmouth bass aggressively guard nests from predators and are easier to catch by anglers during this time of year. Removal of males by anglers decreased the number of bass offspring because of increased round goby predation of unguarded nests (Steinhart et al. 2004). Businesses that smallmouth bass anglers patronize could be adversely affected by such closures.
Altered business opportunities: The concern over Sudden Oak Death Syndrome caused by the pathogen Phytophthora ramorum is causing drastic changes in available nursery stock by nurseries and landscape businesses. This clearly impacts the profitability of these businesses and choice by consumers and could devastate oak forests nationwide (Chornesky et al. 2005; Rizzo and Garbelotto 2003).
Annual harvests of oysters in Long Island Sound averaged over 680,000 bushels during 1991 through 1996. After Haplosporidium nelsonii (MSX) invaded in 1997 and 1998, oyster harvests decreased from 1997 through 2002 to an average annual harvest of 119,000 bushels with a low of 32,000 bushels in 2002. The overall ex-vessel value of oyster farming dropped 96% in 10 years from $45 million in 1992 to $2 million in 2002 (Sunila et al. 1999).
Non-native algae introduced into the Hawaiian Islands costs Maui alone about $20,000,000 annually due to algae fouling the beaches and subsequent lost tourism (Carroll 2004; Keeney 2004; Univ. Hawaii 2006).
Sea lampreys were introduced into Lakes Ontario and Erie during the construction of the Welland Canal and quickly spread to the other Great Lakes. The sea lamprey is a parasite that attaches itself to fish, eventually killing them, and has devastated commercial and recreational Lake Trout fishing in the Great Lakes (Lawrie 1970).
Australian spotted jellyfish were introduced into the Gulf of Mexico in 2000 and occurred in such massive numbers that shrimping operations were shut down because jellyfish clogged shrimp nets (Graham et al. 2003).
Altered ecosystems and recreational opportunities: The submersed aquatic plant hydrilla, forms dense canopies at the water surface that raise surface water temperatures, change pH, exclude light, and consume oxygen, resulting in native plant displacement and stunted sport fish populations. This example of an altered aquatic ecosystem caused by an invasive aquatic weed also negatively affects recreation and businesses that depend upon that human activity (Colle et al. 1987).
Invasive species are those that are not native to the ecosystem under consideration and that cause or are likely to cause economic or environmental harm or harm to human, animal, or plant health. Plant and animal species under domestication or cultivation and under human control are not invasive species. Furthermore for policy purposes, to be considered invasive, the negative impacts caused by a non-native species will be deemed to outweigh the beneficial effects it provides. Finally, a non-native species might be considered invasive in one region but not in another. Whether or not a species is considered an invasive species depends largely on human values. By attempting to manage invasive species, we are affirming our economic and environmental values. Those non-native species judged to cause overall economic or environmental harm or harm to human health may be considered invasive, even if they yield some beneficial effects. Society struggles to determine the appropriate course of action in such cases, but in a democratic society that struggle is essential.
Many invasive species are examples of "the tragedy of the commons," or how actions that benefit one individual's use of resources may negatively impact others and result in a significant overall increase in damage to the economy, the environment, or public health. In ISAC’s review of Executive Order 113112, the public domain is specifically represented; however, the implementation of the NISMP has prompted concerns over the rights of personal and private property owners. Property rights are of great importance in the U.S. and one outcome of the NISMP should be to recognize the right to self determination by property owners and promote collaboration on invasive species management. The right to self determination is an important concept in a democratic society, however, with that right comes personal responsibility and stewardship, which includes being environmentally responsible. The natural environment that our society enjoys, recreates in, and depends upon to support commerce must be conserved and maintained. Effective invasive species management is just one aspect of conserving and maintaining our nation’s natural environment, the economies it supports, and the high quality of life our society enjoys.

Aquatic Nuisance Species Task Force, U.S. Fish and Wildlife Service, and U.S. Coast Guard. 2005. Protect Your Waters. Harmful Aquatic Hitchikers: Others: Whirling Disease. [Online]
Bisognano, J.D., K.S. McGrody, and A.M. Spence. 2005. Myocarditis from the Chinese sumac tree. Annals Internal Medicine 143(2):159.
Brasier, C.M. and K.W. Buck. 2001. Rapid evolutionary changes in a globally invading fungal pathogen (Dutch elm disease). Biological Invasions 3:223-233.
Carroll, R. 2004. Maui battling seaweed invasion. Assoc. Press. [Online]
Cavey, J.F., E. R. Hoebeke, S. Passoa, and S.W. Lingafelter. 1998. A new exotic threat to North American hardwood forests: an asian longhorned beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae). I. Larval description and diagnosis. Proc. Entomol. Soc. Wash. 100 (2):373-381.
Chorensky, E.A., A.M. Bartuska, G.H. Aplet, K.O. Britton, J. Cummings-Carlson, F.W. Davis, J. Eskow, D.R. Gordon, K.W. Gottschalk, R.A. Haack, A.J. Hansen, R.N. Mack, R.J. Rahel, M.A. Shannon, L.A. Wainger, and T.B. Wigley. 2005. Science priorities for reducing the threat of invasive species to sustainable forestry. BioSci. 55(4):335-348.
Colle, D.E., J.V. Shireman, W.T. Haller, J.C. Joyce, and D.E. Canfield. 1987. Influence of Hydrilla on Harvestable Sport-Fish Populations, Angler Use, and Angler Expenditures at Orange Lake, Florida. North American Journal of Fisheries Management 7:410-417.
Colorado Division of Wildlife. 2006. Whirling disease and Colorado’s trout.
DiTomaso, J. 2001. Element stewardship abstract: Centaurea solstitialis L. Weeds on the web: The Nature Consevancy wildland invasive species program. ]tp://
Friedercici, P. 1995. The alien saltcedar. Am. For. 101:45-47.
Graham, W.M., D.L. Martin, D.L. Fedder, V.L Asper, and H.M. Perry. 2003. Ecological and economic implications of a tropical jellyfish invader in the Gulf of Mexico. Biological Invasions 5(1-2) 53-69.
Halstead, J.M., J. Michaud, S. Hallas-Burt, and J.P Gibbs. 2003. Hedonic analysis of effects of a nonnative invader (Myriophyllum heterophyllum) on New Hampshire (USA) lakefront properties. Environmental Management 32(3): 391-398.
Johnson, S. 1986. Alien plants drain western waters. The Nature Conservancy News, Oct-Nov 1986.
Keeney, T.R.E. 2004. Written testimony before the Subcommittee on Fisheries Conservation, Wildlife and Oceans, Committee on Resources, U.S. House of Representatives.
Knapp, P.A. 1996. Cheatgrass (Bromus tectorum L.) dominance in the Great Basin Desert: History, persistence, and influences to human activities. Global Environ. Change 6(1):37-52.
Krakowski , J., S.N. Aitken, Y.A. El-Kassaby. 2003. Inbreeding and conservation genetics in whitebark pine. Conservation Genetics 4:581-593.
Lawrie, A.H. 1970. The sea lamprey in the Great Lakes. Transactions of the American Fisheries Society 99:766-775.
Lym, R.G. and C.G. Messersmith. 1985. Cost effectiveness of leafy spurge control during a five-year management program. North Dakota Farm Res. 43(1)7-10.
Lym, R.G. and D.R. Kirby. 1987. Cattle foraging behavior in leafy spurge infested rangeland. Weed Technol. 1:314-318.
Maddox, D.M. 1979. The knapweeds: Their economics an biological control in the western states, U.S.A. Rangelands 1(4):139-141.
Pimentel, D., L. Lach, R. Zuniga, and D. Morrison. 2000. Environmental and economic costs of non-indigenous species in the United States. Biosci. 50(1):53-65.
Richardson, D.M., P. Pysek, M. Rejmanek, M.G. Barbour. F.D. Panetta, and C.J. West. 2000. Naturalization and invasion of alien plants: concepts and definitions. Diversity and Distributions 6:93-107.
Rizzo, D.M. and M. Garbelotto. 2003. Sudden oak death: Endangering California and Oregon forest ecosystems. Frontiers in Ecology and the Environment 1:197-204.
Steinhart, G.B., E.A. Marschall, and R.A. Stein. 2004. Round goby predation on smallmouth bass offspring in nests during simulated catch-and-release angling. Transactions of the American Fisheries Society 133: 121-131.
Stevens, K.L. 1986. Alleopathic polyacetylenes from Centaurea repens (Russian knapweed). J. Chem. Ecol. 12:1205-1211.
Sunila, I., J. Karolus, and J. Volk. 1999. A new epizootic of Haplosporidium nelsoni (MSX), a haplosporidian oyster parasite, in Long Island Sound, Connecticut. Journal of Shellfish Research 18(1): 169-174.
U.S. Fish and Wildlife Service, 2003. Costly fires hurt wildlife habitat. [Online]
Univ. of Hawaii. 2006. Invasive marine algae of Hawaii. [Online]
U.S. Center for Disease Control. 2000. Fight the Bite. [Online]
USDA-APHIS/FS. 2000. Draft pest risk assessment for importation of solid wood packing materials into the United States.
Weiser, C. 1998. Economic effects of invasive weeds on land values (From and agricultural banker’s standpoint). Proc. Colorado Weed Summit April 7-8, 1998. p. 35-38.
Whisenant, S.G. 1990. Changing fire frequencies on Idaho’s Snake River Plain: Ecological and management implications. The Station. Nov. 1990 (276) Ogden, UT: General Technical Report INT – USDA Forest Service Intermountain Research Station.
Young, S, W.W. Brown, and B. Klinger. 1970a. Nigropallidal encephalomalacia in horses caused by ingestion of weeds of the genus Centaurea. J. Amer. Vet. Med. Assoc. 157:1602-1605.
Young, S., W.W. Brown, and B. Klinger. 1970b. Nigropallidal encephalomalacia in horses fed Russian knapweed (Centaurea repens L.). Amer. J. Vet. Res. 31:1393-1404.
Appendix 4: On-line Resources
Weed Research and Information Center (WeedRIC) Pampasgrass and Jubatagrass Threaten California Coastal Habitats brochure:
California Horticultural Invasive Prevention partnership (CAL-HIP) PlantRight campaign
Missouri Botanical Garden’s Exotic Plant Pests page:
American Nursery & Landscape Association (ANLA):
Weed Science Society of America:
The Nature Conservancy:
The Nature Conservancy Invasive Species Initiative:
ISAC White Paper on Definition of Invasive Species:
National Invasive Species Council:
USDA’s Agricultural Research Service:
USDA’s National Arboretum:
USDA’a Henry A. Wallace Beltsville Agricultural Research Center:
USDA’s Agricultural Research Service’s Crop Production and Protection National Program:
USDA’s Agricultural Research Service’s Technology Transfer Office:
USDA’s Agricultural Research Service’s Research Project: Crop and Weed Responses to Increasing Atmospheric Carbon Dioxide:
USDA’s Natural Resource Conservation Service Plants Data Base:
Plant Variety Protection Act: provides an archive of images related to invasive species, with particular emphasis on educational applications.

[1] Executive Order 13112 defines an invasive species as “an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.” Also see Appendix 3.

[2] Biological systematics is the study of the diversity of living organisms through time and includes determining their taxonomic identities.
[3] Work at the Missouri Botanical Garden to compile a comprehensive inventory of the cultivated plants in North America was presented.
[4] Executive Order 13112 defines an invasive species as “a species that is non-native to the ecosystem under consideration and whose introduction causes or is likely to cause economic or environmental harm or harm to human health (also see Appendix 3).