Tuesday, September 01, 2009

Invasive Species: Simple at First Glance

Invasive species issues seem simple at first glance. A species is introduced, establishes reproduces and begins to alter the new ecosystem, or negatively impacting human health and well being. Direct, strong adverse interactions that effect human health rise to the forefront of community awareness and efforts to reduce or eliminate the threat. Much is spent to prevent or ameliorate the introduction or control of invasive species such as:

Asian longhorned beetle (Anoplophora glabripennis)
Asian tiger mosquito (Aedes albopictus)
Brown citrus aphid (Toxoptera citricola)
Codling moth (Cydia pomonella)
Colorado potato beetle (Leptinotarsa decemlineata)
Cotton aphid (Aphis gossypii)
Diamondback moth (Plutella xylostella)
Emerald ash borer (Agrilus planipennis)
European corn borer (Ostrinia nubilalis)
Formosan subterranean termite (Coptotermes formosanus)
Glassy-winged sharpshooter (Homalodisca coagulata)
Gypsy moth (Lymantria dispar)
Hemlock wooly adelgid (Adelges tsugae)
Insect Biocontrol
Japanese beetle (Papillia japonica)
Mediterranean fruit fly (Ceratitis capitata)
Mexican fruit fly (Anastrepha ludens)
Oriental fruit fly (Bactrocera dorsalis)
Pink bollworm (Pectinophora gossypiella)
Pink hibiscus mealybug (Maconellicoccus hirsutus)
Red imported fire ant (Solenopsis invicta)
Russian wheat aphid (Diuraphis noxia)
Silverleaf whitefly (Bemisia argentifolii)
Wheat stem sawfly (Cephus cinctus)

Things get more complicated when the invasive species threat is not direct. The difficulties of the science, and the lack of absolutes, lead to statements of concern and even desperation as desired outcomes collide. Nan Wishner, Chair Emeritus of the City of Albany Integrated Pest Management Task Force and a member of the Stop the Spray East Bay Steering Committee writes that the total elimination “.. LBAM(light brown apple moth) is not feasible, the state plans to carry out a multi-year eradication program involving mass pesticide applications; that program’s first year cost an estimated $97 million.”

As the level of complication and complexities rise, the wicked inconvenience of invasive species issues seems to compel stakeholders to define their perceived problem in terms of their own unique a priori outcome desires. This means that each group of stakeholders has a slightly different working definition of invasive species making it very hard to reach consensus. The end game then becomes one of my way or the highway.

Any farmer or gardener will tell you that pests such as pathogens, insects and weeds are eternal; they do the best they can to control and eliminate the daily invasion that reduce monetary or aesthetic yield, knowing full well that the task is akin to sticking a finger in a dike. If farmers were to decide that weeds cannot be eliminated and gave up, we all would starve. Why then is it different when we set out to protect a natural area? Some would say we should just allow the invasion to create a new balance in time in a new, novel ecosystem and learn to live with it. In deed that is one option. It is the option of the property owner who chooses not to landscape, and cuts the brush around the buildings only to prevent fire and rodent damage. The neighbor who chooses to install and maintain an ornamental work landscape that requires endless removal of invaders is no less wrong in his choice than the former. So too our natural areas are like garden, rich in complexity and under constant and it would seem permanent attack. The issue at this level is one of limited resources as well as competing goals. Don’t use chemicals to control invaders in natural areas, and therefore allow a dramatically altered ecosystem, and deal with the unintended unexpected consequence later. Use chemical and reduce the impact, but suffer the affects of chemical pollution of air, earth or water.

So far we are speaking about the easy side of invasive species management and politics. Mark A. Davis writes in his new book, Invasion Biology, Oxford University Press, 2009, that ” …it is usually much easier to assess impact than it is to determine the series of ecological causes for it.” (White et a. 2006) Because current science has focused on the assessment of impact and not upon the mechanisms of ecological cause, certain stakeholders can reasonably claim that there is either no science or not enough science to support the dedication of resources. The present reliance on science as religion with the concurrent expectation that scientist-priests will rule on great issues ex cathedra and never ever change their minds fails to recognize that science is a tool for use in public discourse and public valuation exercises; science is not the end of the conversation but the beginning.

As Davis point out on page 151 of “Invasion Biology”, the ever-changing dynamic relationship between an ecosystem (itself ever-changing) and social systems (also in a constant state of flux) provides an overwhelming set of choices for environmental decision makers, land managers, and public policy deciders. Solutions and recommendations for invasive species will never be static and the casual observer will be endlessly confused. The tendency to throw up one’s hands in surrender will be powerful and the call to do nothing will be loud.

Controlling an invasive species or even eradicating it is most cost effective before it has actually done anything harmful. The idea that the LBAM should be allowed to spread because it has not yet wiped out a crop demonstrates the difficulty of getting people to care about something that has not actually happened yet. USDA has asked for more funding but because the problem is not pandemic begging is the order of the day. We as a society are loathe to spend money on something that has not happened yet. Better to wait til someone turns to crime and then incarcerate them than to pay less up front in education and work force development is our motto and so it is with invasive species

“Light brown apple moth is a recognized agricultural pest. Moths, such as light brown apple moth (LBAM) (Epiphyas postvittana), banana moth (Opogona sacchari), and nettle caterpillar (Darna pallivitta), are [known] pests of various tropical /subtropical crops, limiting production, and may severely disrupt trade if not detected and allowed to become established in primary growing areas. LBAM also attacks temperate crops and has recently been identified in California as a new invasive species. Because LBAM threatens a multibillion dollar industry in California, alone, CDFA and APHIS, have asked ARS scientists to help develop methods for LBAM control. Research Gaps including effective management of moth pests of tropical /subtropical crops requires the development of: 1) user-friendly, economical, and environmentally acceptable technologies; 2) area-wide integrated pest management (IPM) systems for moth suppression; and 3) systems approaches to prevent pest movement on export commodities.” (http://www.ars.usda.gov/SP2UserFiles/Program/304/ActionPlan2008-2013/2h.pdf)

If gardeners waited until the weeds crowded out the tomatoes we would never have spaghetti sauce. Gardeners know that early detection and rapid response is the key to a a successful harvest and react without waiting to see if the scientist can publish; invasion of the garden are dealt with summarily. But on an ecosystem level we sometimes choose to wait until the kudzu covers the telephone poles of a million acres before buying the special machinery needed to keep the roads clear. We will carefully not try to reduce the level of the apple moth so that we have a reduction in chemical impact, as we loose the harvest of the fields, hoping that when the moth is finished it does not adapt to our natural areas and begin to be a factor in the wild fires of California as other invasive species already are. The call is to find consensus and to work together towards a common management goal using the tools of science and the techniques of IPM to reduce the toxicity of the solution and the level of the pest simultaneously.

Somehow we need to find away between do nothing at all and waiting until there is nothing to be done. But I digress…until another species catches my attention.

1 comment:

Cindy said...

I must admit, that throwing up my hands and doing nothing at all is the way I lean. On deeper thought, not exactly doing nothing at all, but ceasing and desisting from doing that which is harmful..if one knows or can decide what that is

Would we starve if the 'weeds' had their way? How did we live before the garden of eatin' needed weedin'?