Saturday, December 31, 2011

The World of Invasive Species is Divided into three Camps

               The world is divided into three groups when  it comes to invasive species. The first and largest is the group that has no idea, information or opinion about what an invasive species is or may be let alone whether there is reason for concern or not. This largest of constituencies is only interested in non human species when they slither into its bedrooms (pythons), bring disease (tiger mosquitoes), decreases harvest of baseball bats (emerald ash borer) or pulls down power lines (kudzu) needed to stay connected to social media.

               The second interest group has decided the information at hand warrants no concern and no focus or allocation of resources or consideration. In some sense this group has decided to live for today knowing that tomorrow will take care of itself as well as any human generations that may come. The third broad constituency, on the other hand,  sees a problem  and want to prevent what it can and fix what is damaged in order to preserve a future of maximum opportunities based upon present understandings of biological diversity. This last group's  invasive species positions are based upon an understanding that human welfare both directly and indirectly depends on the environment, a concept that the first group never thinks about and the presumptions about which the second groups has questions.

               Irreversible environmental damage to ecological system resources and services negatively affect  future generations' abilities to achieve quality of life goals. The chronic disruption of natural ecosystems caused by human development activities include the introduction and establishment of novel species that replace existing species' relationships and interactions. A major difficulty arises in any effort to assign a value that would allow an easy decision or choice as to what steps to take in regards to an invasive species issue. The  challenge is in determining the estimation of the economic value of environmental resources, service or effects, as well as the possible conflicts between the discounting of ecological effects and long-term environmental and sustainability concerns.[1]

               In a sense the whole idea of environmental evaluation lead directly to a conflict between the conservation of environmental assets including indigenous species patterns and aggregations versus traditional patterns of economic development such as the clearance of land for agriculture and urban development.  To safeguard future generations' access to ecological services, present human activities (development) would seem to require that the present generation restrict the use of scarce ecological resources.[2] But that is pretty much not going to happen in a world staring at human population numbers growing  to 9 plus billion within this century.

                If an invasive species has not yet made a measurable or economical impact on a field, landscape or natural area, most people ask why spend money on something that has not happened? It is the same problem facing schools versus prisons; why spend money on education of many individuals to prevent crimes of a few when one can wait until a crime is committed and then remove the specific individual from the community as a whole. Of course when it comes to personal health, we rather reluctantly almost get the prevention thing because our mothers told us so. When it comes to consideration of the environment, however, Mother's advice goes out the window. 

               The first two group's preoccupation with the present results in a cascading series of decisions that extend beyond invasive species inaction. Bridges are not repaired, libraries are closed and research into environmental tools are shut down. USDA-ARS, for example, is closing its Kika de la Garza Subtropical Agricultural Research Center founding in 1935 in Texas along with 9 other locations across the US because it can no longer afford to support the scientific work done there on:  

1) Integrated pest management (IPM) of parasites and diseases of honey bee colonies; 2) Biological control methods used to identify and defeat present and potential pest threats to Rio Grande Valley agriculture; 3) Organic farming systems utilizing holistic approaches to healthy and nutritious food production; 4) Quarantine treatments of subtropical fruits and vegetables; 5) Post harvest treatments of produce for disinfestations by non-chemical means; 6) Aerial remote sensing of agricultural problems; and 7) Pesticide tolerance of vegetables, ornamental, and specialty crops for registration labeling and EPA compliance.

               Another example of groups one and two unintentional and unplanned collaboration  is the budget driven decision by the U.S. Army Corps of Engineers to stop funding its enormously successful Aquatic Plant Control Research Program. The program traces its original to the catastrophic introduction of a non-indigenous aquatic plant, water-hyacinth (Eichhornia crassipes (Mart.) Solms), which rapidly infested the waters of Florida and Louisiana.  The elimination of terrestrial and aquatic biological control research is short sighted, foolish and just plain stupid, but reflects a society concerned now with that it can get today not what it will leave for its children tomorrow.   

               Thus, it comes down to a series of trade-offs as to what to do with invasive species, their introduction, establishment and control. This is pretty much the life of a gardener; a series of morning decisions based on unsatisfactory trade-offs involving resources such as time and money. It also makes the gardener's case that an touch of prevention is worth more than a costly excursion of eradication and control after the fact. But who has time to listen to gardeners anymore?

[1] Jan Douwe Meindertsma. “Agricultural Research for Development” [accessed December 31, 2011]
[2] David Pearce. 1993. Valuing The Environment: Past Practice,Future Prospect. [accessed December 31, 2011]

Wednesday, December 28, 2011

Recommendations to NISC from the ISAC Meeting held December 6-8, 2011

December 20, 2011

TO: Members of the National Invasive Species Council (NISC)
SUBJECT: Recommendations to NISC from the ISAC Meeting held December 6-8, 2011
During the December 6-8, 2011 meeting held in Washington, DC, ISAC agreed upon the following recommendations:

Recommendation #1: ISAC recommends that NISC support and encourage the National Research Council of the National Academy of Sciences review of frameworks for the validation of advanced molecular assays for aquatic invasive species detection technologies and their protocols.

Recommendation #2: Expanding trade across the Pacific poses a dual challenge to the control of invasive species. First, there is a high potential for introductions of new species in both directions.
Second, there is a high potential that some introduced species will become invasive because of similarities between the climates and ecology of central and eastern Asia and North America.
In light of these challenges and the potential negative impacts of the introduction of invasive species in either direction across the Pacific on the economies and environment of the U.S. and its trading partners in eastern Asia, ISAC recommends that the Department of State seek the cooperation of appropriate agencies in convening a multilateral meeting of scientists and governmental representatives from APEC countries to develop measures to prevent the introduction of invasive species in the course of transpacific commerce.

Recommendation #3: ISAC recommends that the U.S. Army Corps of Engineers immediately reinstate the funding for the Aquatic Plant Control Research Program due to its national importance in the control and management of aquatic invasive plants.

E. Ann Gibbs
Chair, Invasive Species Advisory Committee
Maine Department of Agriculture

Wednesday, December 21, 2011

Thinking about Invasive Species, Plants and Definitions

Initial damage appears as thinning and dieback in the upper canopy of the tree as larvae feed under the bark they damage the conductive tissue  

               Some plant species are introduced by human activity into new ecosystems at such a rate that they can overcome the odds and establish themselves in the landscape. A few of these plant species do more than just establish they multiply so fast and so aggressively as to crowd out any other plant species creating a biological desert bereft of diversity. Some of these species have become notorious in the last few decades such as kudzu (Pueraria montana (Lour.) Merr. var. lobata (Willd.) Maesen & S. Almeida) and the various salt cedars or, tamarisks (Tamarix spp.); some such as common barberry (Berberis vulgaris L.) in the 18th century or field bindweed (Convolvulus arvensis L.) in the 20th century began their rise to pest status even before we used the term invasive species. Interestingly enough the colony of Connecticut tried to ban barberry in 1726 way before there even was a United States. [Connecticut keeps trying to ban plants. 2010]

               These plants are not indigenous to North America and so by extension we begin think all alien non native plants are suspect. The cognitive dissonance that arises when we find out wheat (Triticum spp.) is also not native is disturbing to a native only perspective. Then there is the little problem of impact, benefit and harm when it comes to judging a species place in the ecosystems in which we find ourselves. And just to layer on the complications, the non native exotic plant itself may be harmless but maybe a host for invasive hitchhikers (insects and pathogens) The native ash tree. for exmaple, can be a vector or a transport platform for the non native emerald ash borer (Agrilus planipennis Fairmaire) which destroys both native and non native ash species. [A Menacing Discovery Of the Emerald Ash Borer in Moscow. 2007]  

               Defining invasive species is the first step to finding solutions.  A good resource is the  Invasive Species Definition Clarification and Guidance White Paper from 2006 which 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.[1]

[1] Invasive Species Defined in a Policy Context: Recommendations from the Federal Invasive
Species Advisory Committee. 2006. K. George Beck, Kenneth Zimmerman, Jeffrey D. Schardt, Jeffrey Stone, Ronald R. Lukens, Sarah Reichard, John Randall, Allegra A. Cangelosi, Diane Cooper, and John Peter Thompson*

Tuesday, December 20, 2011

Loss of an Herbarium: another "library" lost; the decline of scientific infrastructure

Everything you need to know is NOT on Google and our lack of attention tyo scientific infrastrucre is a great threat to the futureThe ARS Crop Production Systems Research Unit Herbarium (acronym SWSL) at Stoneville, Mississippi is being placed on excess and is available to any USDA-ARS management unit that is interested in acquiring and maintaining it.

The herbarium holdings include 27 metal cabinets (good to fair condition), 4 laminated cabinets (poor condition), about 18,000 mounted specimens representing about 5,700 species, a few un-mounted specimens, and limited supplies of mounting paper, folders and glue.  The total floor space required for the herbarium (cabinets and supplies) is approximately 400 square feet. 

The recipient of the herbarium (cabinets and supplies) must take the herbarium as a single unit and pay for packing and shipping or transport costs of cabinets and all materials related to the herbarium.  The estimated weight of cabinets, specimens, and supplies is about 10,000 pounds and 22,000 cubic feet.

If you are interested in acquiring the herbarium or require additional information, please contact Dr. Krishna Reddy at  (phone             662-686-5222      ) with a copy to Dr. Charles Bryson  by Friday COB, December 23, 2011.

Saturday, November 26, 2011

What is an Invasive Species?

What is an "invasive species"?

               An answer will depend whom you ask, and to a large extend what outcomes the person asked expects.

That was not a very helpful answer. Could you give a few answers that show different definitions of an "invasive species"?

               Sure.  First let's look at some words that are used to describe a change in species distribution that upset existing ecosystem balances and cause changes in ecosystem services that lead or may lead to system resource change or collapse:  adventive, alien, casual, colonizing, cryptogenic, escaped, endemic, established, exotic, foreign, immigrant, imported, introduced, invasive, native, naturalized, nonindigenous, noxious, nuisance, pest, spreading, temporary, tramp, transferred, transformer, transient, translocated, transplanted, transported, travelling, waif, and weedy. (Colautti & MacIsaac, 2004) Brendan Larson's thirteen meta categories to consider when we try to come to grips with a definition are: invaders, terrorists, piggy-backers, opportunists, spawn, mirrors of ourselves, providers, hybrids, tricksters, matrix elements and dynamic matrices, transients, founts of life and creation, teachers and instructors that force us to think about our assumptions. (Larson, 2007)   

Yes that is all very nice, but I want a simply straightforward definition.   

               Well, because of the complexities that arise from the ecosystems themselves and the many stakeholders and interested parties, there are many definitions. This happens because it is easier to start with an outcomes and work backwards to a definition. In other words we color the definition with preconceived ideas and concepts. This even our choice of words predisposes us to a view of the problem even before we have a definition. The very choice of the word invasive presumes a pejorative meaning, because natural system stakeholders so the negative impact of what to them looked like invasions.

Yeah Yeah Yeah, but I am just passing through and I do not have a lot of time for this, just give me a definition.

               The International Union for Conservation of Nature, (IUCN) describes invasive species as “animals, plants or other organisms introduced by man into places out of their natural range of distribution, where they become established and disperse, generating a negative impact on the local ecosystem and species.” Invasive species can negatively impact human health, the economy (i.e. tourism, agriculture), and native ecosystems. These impacts may disrupt the ecosystem processes, introduce diseases to humans or flora and fauna, and reduce biodiversity.
               Invasive Species Definition Clarification and Guidance White Paper Submitted by the definitions Subcommittee of the Invasive Species Advisory Committee (ISAC) in 2006 sought to make clear the US Executive Order 13112  which 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.”   (Beck, et al., ISAC 2006)
               In California an invasive plant is defined by Cal-IPC as  invasive non-native plant species that threaten wildlands and are are not native to, yet can spread into, wildland ecosystems, and that also displace native species, hybridize with native species, alter biological communities, or alter ecosystem processes.   This definition does not address diseases, insects or animals, just plants and only if they invade California wildlands with native habitat values. The invasive plant definition does not include plant species found solely in areas of human-caused disturbance such as roadsides and cultivated agricultural fields.  For these human disturbance areas the terminology or word would be weed. The California Native Plant Society has a straight forward definition of an invasive exotic plant, to wit: "a plant which is able to proliferate and aggressively alter or displace indigenous biological communities."
               The European Commission on the Environment states that "Invasive Alien Species are animals and plants that are introduced accidently or deliberately into a natural environment where they are not normally found. They represent a serious threat to native plants and animals in Europe, causing € millions worth of damage every year."

Great now I need to understand what a native species is? I don't suppose there is a simple definition. is there?

               That would be a different blog posting. Definitions of native run into the same fuzzy definition problem  that we are skirting in this blog. The closer you look the harder it is to pin down exactly what the term means. What exactly is native at 650 ppm CO2 for example is a question no one is talking about. Suppose we move an endangered species to a new site; is it native now?

This invasive business requires too much thinking. Can't you make this simpler?

               Sure: an invasive species is the wrong pathogen, plant, animal in the wrong place at the wrong time.

Works Cited

Beck, K. G., Zimmerman, K., Schardt, J. D., Stone, J., Lukens, R. R., Reichard, S., et al. (ISAC 2006). Invasive Species Definition Clarification and Guidance White Paper. Retrieved March 2009, from
Colautti, R. I., & MacIsaac, H. J. (2004). A neutral terminology to define ‘invasive’. Diversity Distrib. , 10, 135-141.
Larson, B. M. (2007). Thirteen ways of looking at invasive species. In D. R. Clements, & S. J. Darbyshire (Eds.), Invasive plants: Inventories, strategies and action. Topics in Canadian Weeds Science (Vol. 5). Canadian Weed Science Society – Société canadienne de.

Thursday, November 24, 2011

Once 90% of US were Self-Employed

Maryland Farms During World War II

               In 1790, 90 percent of the total population of 3,929,214 in the United States were self employed farmers. By self employed I mean that they lived or died by their ability to produce for themselves food, fuel, fiber, forage, feed, flowers (herbs for medicine), and forest products for housing. Large international organizations played a supporting role and employed few people. Laws were made to protect the interests of the self employed businesses that were the family farm. For the most part laws were not made to benefit the needs and wants of large corporate employers unless those laws directly impacted the needs of small business.
               It was in the interest of large farmers to keep control of the political process in order to ensure the maximum distribution of governmental largess and resources so laws were enacted to restrict policies enfranchisement to those who owned land for example, or in the case of slavery, those who actually produced the profits. The "employees" were not part of the political debate because they were either legally or practically excluded from the important affairs of those in political control.
               The tension between the needs of the small farmer and the large land owner resulted in tensions over the role of government and the use of government revenues. Public  versus private road systems or  other transportation infrastructure such as canals were issues for debate. Even the idea of public schools was up for controversy, begging the question as to why an individual should have to pay out of his profits so another could be educated;  a question related to why one should pay for a road or bridge from public monies so that another  could use it.  Whatever the political argument, implicit in most decisions was the concept of an individual self employed agriculturally based family unit that was dependent on the profitable actions or successful family business outcomes. And more to the point the political conversations involved a majority of the population by virtue of the total number of people impacted directly by the policy decision outcomes.
               Today with a total population exceeding 300 million, fewer than 1 percent of us have a direct link to a family owned self employed business. Even the total number of self employed people today amounts to only 11 percent of the population of the United States. This means that the majority of us work for someone or something else other than ourselves. The politics of Privilege and Power becomes that of impacting legislation and policy in the 21st century while protecting the interests of the smallest number of us needed to keep power in order to distribute the proceeds of being in power.  Farming no longer has the political muscle to be a major player, but self employed small business as well as international corporate interests do have a major role even if they only directly represent a small portion of the total population. As in the beginning in 1790, government is not instituted to represent the interests of all of us, but to enable the distribution of resources to the smallest number of us while at the same time keeping the rest of us quiet. On other words, the challenge for the few is to calculate the minimum distribution of resources to the majority necessary to buy a majority's acquiescence to the holding of power by the fewest number possible.

Tuesday, November 22, 2011

Japanese Cedar Longhorned Beetle Found in Maryland

Pest Alert: Japanese Cedar Longhorned Beetle Found in Maryland For The First Time

From: Bob Trumbule, Entomologist, Maryland Department of Agriculture Plant Protection and Weed Management      

Japanese Cedar Longhorned Beetle, Callidiellum rufipenne, has been found and identification confirmed in Maryland for the first time. It was found on Cryptomeria japonica 'Yoshino' planted in the Severn area of Anne Arundel County. Identification was made by Gaye Williams and has been confirmed by SEL. We have been in contact with the Department of Agriculture of the out of state supplier of the nursery stock to see if the problem started there and are currently performing a survey in Maryland to determine whether it is established in the area where the infested stock was planted. Further information will be forthcoming as we get it.

Be on the lookout for this pest. It was detected due to dieback of leaders and branches of the infested plant material. Fully developed adult beetles were found in tunnels in the infested plants.

Please feel free to contact me (
Bob Trumbule)) with any questions  

Monday, November 14, 2011

FYI FREE Class: Responsible Pesticide Use, Home Owner Awareness

Responsible Pesticide Use including Alternatives
with John Peter Thompson
November 19, 2011 9 - 1 a.m.
Prince George's Community College - Westphalia Campus
to register call:

Sunday, November 13, 2011

Ruminations on Harm and Invasive Species

               The wicked inconvenience of invasive species is wrapped up in definitional fuzziness.[1] Bertrand Russell must of been channeling invasion biology when he wrote that "everything is vague to a degree you do not realize till you have tried to make it precise,  and everything precise is so remote from everything that we normally think, that you cannot for a moment suppose that is what we really mean when we say what we think." (Bertrand Russell. 1918.  Logic & Knowledge: The Philosophy of Logical Atomism )

               In many debates the conversation rarely moves past the definition of the word invasive, never reaching the dark recesses of taxonomy and the outer limits of agreeing on what exactly a species is. Because the interest groups, both those worried about invasives and those who are dismissive of any concern, stay far away from the tail-end of the general definition of an invasive species - the part that refers to harm. The U. S. 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.” As one of the authors of the white paper referenced in the link above, I remember the conversations surrounding the challenge of what we mean and what we do not mean by the term invasive species. I also recall the problem of dealing with the idea and consequences of harm. In a real sense, it for many stakeholders it comes down to the old adage that one knows harm when one sees it.

               So what exactly is harm? The word harm comes to us through the centuries from the Old English word  hearm that is related to Old Norse's word harmr meaning grief and is related to the Old High German word harm which is translated by our modern English word injury. It is interesting to note the Old Slavonic word sramǔ which is rendered by the English word disgrace.  Today the modern English noun, harm, is defined as 1. a physical or mental injury or damage or 2. a moral evil or wrongdoing.  Harm can therefore be any physical damage to the body caused by violence or accident or fracture. By analogy or inference we can think of a landscape or ecosystem as a body and see the extension of meaning as a species introduced by human activity displaces indigenous species. Harm can also be defined as an occurrence of a change for the worse (the act of damaging something or someone) which on the surface seems to succinctly explain the invasive problem but in itself begs the question as to how to assign a value to worse. Again we tend to resort to know it when we see it to escape the tedious process of actually thinking through the logic of the definitions.

               Armed with the above definition it is clear that the problem is one of valuation. How does one assign a value to change? What do we mean by change for the good or change for the worse?  If I see a tree falling in my direction , self-preservation assigns a value of bad and I move to correct my path so as to disallow a presumed negative outcome - on other words I get out of the way. If I have a tree leaning towards my house and I notice that each month it leans a little more, I will assign values to the potential damage to the house that may come at some point versus the cost of being proactive and cutting down the tree or if possible staking it.  I am now performing complicated future value calculations taking a discount rate and considering opportunity costs. I am assessing risk.

               In the examples above, I am the only decider in the equation. The problems and solutions revolve around me and there is no other human parameter to consider. However if we add another person to the equation the process of valuation can become complicated quickly and gives rise to one of the reason we have societal laws. If the leaning tree is not on my property, and for example is a walnut, my neighbor for his own economic reasons may wish to let the tree grow to harvest the wood at a later date when the market return is better. Short of altruism or laws his concern is not harm to my house. It is more profitable for him to externalize the problem onto me. Of course he needs to figure the potential loss of access to when it falls onto my property.

               Now consider the problem that arise if I decide to grow and sell a non native bamboo such as Phyllostachys aurea and my reason to sell this plant are 1. it reproduces with little input or effort from me and thus is easily propagated for sale and 2.  is easy to market because it grows anywhere and creates quick landscape screening - a ready market for my business. I am making a profit, and from this profit am able to afford health-care. The little issue of its spread onto my neighbors land can be seen as my "free" gift to him or her. I am externalizing some of my production costs because I do not spend time or resources controlling the movement of the plant through the local landscape and ecosystem. I rationalize this by noting how wonderful it is to be able to afford health-care because of this wonderful non native species. My calculations are all done in near time; I benefit right now and tomorrow and am therefore convinced of the overwhelming evidence of positive valuation of the introduction of this species. In fact as far out as I can see the profits from this species will allow me to set aside fungible resources to deal with and hazy problems that may arise in the distant future from any unexpected challenges to the community.

               Now my neighbor happens to be interested in back yard habitats and butterfly is how he or she makes her mortgage payment. The destruction of indigenous biological diversity is bad enough as my plant spreads by sales into common areas such as public parks, but the direct incursion of my profitable plant on to his or her land is intolerable. However I make money by not spending it on control. If I had to spend the amount of money necessary to keep the plant from spreading my profits would go down. My neighbor is of course not interested in my profits which for him or her are realized as costs. In other words my positive valuation becomes their negative valuation. My good species is their bad species. at the neighbor to neighbor level this is fairly straightforward, but when applied to ecosystems, landscapes and communities at large the valuation process spins out of easy linear consideration.

               Keeping the above, contrived situational valuing processes in mind, we need to consider the problem of change in space and in time.  Change in and of itself is dimensionless. Change is the result of an operation. Without change there is no life as we know it.  "Πάντα ε κα οδν μένει - All is flux", said Heraclitus, and any work to hold back change has a cost. Change is geography, change over time lead to change in resource service mix and output possibilities. However doing nothing about change is not an answer that leads to long life. A farmer who says that there is no point to removing weeds in the field every day because the weeds just come back soon as no crop from which he can harvest food. In essence the farmer spends resources, lowering profitability, fending off the incursion and establishment of unwanted species who from experience he judges to have a negative value. The farmer takes a lower short term profit because if in the long term he chooses to do nothing he knows there will be no benefit.

               Harm in invasive species is reduced to a calculation of near and long term benefit that must be redefined continuously. This makes for difficult policy conversations and the difficulty in turns leads to implications in order to enable movement towards predefined goals.  The wicked inconvenience of invasive species lies in part in our inability to address how much harm is permissible, how much change can we permit and who will pay to stop a tree from falling or an ecosystem from collapsing. The cost of preventing can be compared with cost of the benefit lost and a near term decision made, but ho to calculate the loss of future possibilities. For example, the emerald ash borer, an invasive species will reduce the number of ash trees to near zero.  Baseball bats are made from ash trees. What is the value of future loss of yet unmake baseball bats? What other as of yet unknown benefits might come from a future that now has no ash trees to speak of?

               When considering harm how do we value biodiversity's future possibilities against present needs? By homogenizing the landscape, we introduce predictability into our lives many of which because of our urban lifestyles are rife with landscape illiteracy. Who has the time to learn about the interactions between species and which ones may bite or give a rash? If we introduce the same workhorse species around the world then we can presume a certain amount of predictability and therefore unthinking safety as we move about the landscape absorbed in our pursuit of life. Invasive species are co evolutionary partners with mankind. Invasive species are biotic ploughs that chronically disturb the land around human settlements and grind down biological diversity brining a predictable simplicity. This simplistic landscape buys enough time in theory for humans to life in relative safety and work to find alternative resources to provide medicine, air and clean water as the natural ecosystem declines, or so the short term decision model seems to suggest. Humans will extract enough profit to deal with any problem that arises in a distant opaque future.

               To some extent it seems that harm is in the eye of the beholder. Harm that comes today trumps the harm that comes tomorrow for logically if you do not live through the day the problems of tomorrow will not matter to you. Because we use a hyperbolic function to assess the value or size of harm in time, tomorrow's problems which are of the same size or value as today's look smaller to us. When it comes to deciding the value of a future  decision we find ourselves in a negatively curved decision space.  The decision seems to boil down to how much known resource extraction or change is of a benefit now versus how much will this change possibly, maybe cost us then in inaccessible opportunities. This simplistic equation reduces the question about preserving biodiversity to one of a question of preserving the crown jewels of Great Britain; what is the cost of protecting them versus the worth of the metal and stones today.

               To all of the above we now need to add the layman's confusion that rises between assessing risk of harm with managing the risk of harm. "Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete situation and a recognized threat (also called hazard)" according to Wikipedia.  Explicit in the definition is the idea of concrete situations, and not therefore, hypothetical maybes. The Wiki entry continues, "Quantitative risk assessment requires calculations of two components of risk: the magnitude of the potential loss and the probability  that the loss will occur."  The idea of probability is the most slippery deeply inset idea behind risk. It destroys our notion of a world of clearly defined possibilities upon which we build our entire decision making structure . We assume that the world can be defined into convenient terms of absolutes when in actuality we live in a probability universe. By assigning either a value of good or bad we set ourselves up for irrational arguments at the fuzzy boundaries of the problem.   To assess the risk of harm in the future from an introduced species we enter the world of probabilities, an alien ecosystem to many of us in the domain of the general public. A challenge  in risk management is finding the means to measure potential loss and probability of occurrence. How do we go about measuring the potential loss caused by feral cats let loose upon our common public areas or our private garden spaces for instance?