Sunday, August 09, 2009

Invasive species & novel, emerging ecosystems; a challenge

Invasive species wreak havoc upon existing, native ecosystems. Invasive plants can crowd out, consume resources, and provide a platform for pathogens and pests that prey upon existing species. Sometimes invasive plant species can achieve such density as to completely eliminate any competition. The result is a mono-culture – a biological desert. Even if they do not reach this level of damage to an existing ecosystem they can alter it creating damaged or novel ecosystems sometimes referred to as “emerging” ecosystems. A US Forest Service publication defines these altered systems that result when “…species occur in combinations and relative abundances that have not occurred previously within a given biome.”[1] (Hobbs 2006)

Noting that many invasive plants are, for example good carbon sinks, a wicked inconvenience arises. It may be that some novel emerging systems are better at providing many ecosystem services than we think. We have a built in prejudice that disturbed systems are bad; we are judgmental about the negative impacts because of species loss which colors our further considerations. The assumption that pristine is the “best” state leads to the assignment of “bad” for all other choices because we are looking at the historic perceived steady state. Invasive species reduce the number of ecological interactions. They reduce species diversity a major component of our valuation of good.

However invasive species can and do participate in regulation services of ecosystems such as atmospheric gas exchange, erosion, food, biofuels and storm impact processes. What we do not know because there is so little study, is the degree to which they contribute basic ecosystem services. The question arises then: are ecosystems like capitalism powered by creative destruction, a dynamic that not only never is but never can be stationary. Creative destruction describes the process of transformation that accompanies radical innovation.[2] A pristine ecosystem invaded by exotic species is a system subject to radical innovation.

Much of the work of natural area land managers and researchers is geared towards preserving undisturbed environments and biomes. They are working to prevent outside (exotic, alien) species and forces from changing the internal systems of the pristine area. When an invasion happens the loss is forever; the complexities of the original system, the balances, are changed with no possibility of return. And this permanent loss is judged to be bad because it is self evident that if you are trying to preserve something, radical change that disrupts and alters the status quo is bad by definition.
When we add climate change we may be fighting a rear guard action as we try to preserve ecosystems that cannot be sustained as the climates change. For what is native at 600 ppm atmospheric CO2? It will be the invasive species that act as earth’s bandage while new ecosystems come into being. They will provide the fundamental regulation services needs to reestablish functioning biomes. Humans may or may not be a casualty of this reorganization for we are dependent upon these ecoservices that we are paving over, drawing down and mostly taking for granted. Air and water, as well as hydrocarbon, as infinite resources unevenly distributed are a couple of assumptions that influence land use and development decisions. The fact that these resources are finite and depended upon ecosystem services is obscure and not generally part of the conversation.

Does this mean then we give up and let the destruction run rampant because the cause is lost? No for just as the gardener and the farmer daily fight the good fight so environmentalist must do the same. When we remove invasive plants from natural areas, aren’t we just weeding albeit on a larger grander scale? Preserving ecosystems is gardening on a large scale after all.

[1] Hobbs,Richard J.;Arico, Salvatore; Aronson, James; Baron, Jill S.; Bridgewater, Peter; Cramer, Viki A.; Epstein, Paul R.; Ewel, John J.; Klink, Carlos A.; Lugo, Ariel E.; Norton, David; Ojima, Dennis; Richardson David M.; Sanderson, Eric W.; Valladares, Fernando; VilĂ , Montserrat; Zamora, Regino; Zobel, Martin; 2006. Novel ecosystems: theoretical and management aspects of the new ecological world order. Global Ecology and Biogeography, (Global Ecol. Biogeogr.)15, :1–7.

[2] ^ "$200 Laptops Break a Business Model". New York Times. January 25, 2009. Retrieved on 2009-01-27. "Indeed, Silicon Valley may be one of the few places where businesses are still aware of the ideas of Joseph Schumpeter, an Austrian economist who wrote about business cycles during the first half of the last century. He said the lifeblood of capitalism was “creative destruction.” Companies rising and falling would unleash innovation and in the end make the economy stronger."


Samantha said...

Hi! This is a thought that was crystallizing..that perhaps "invasive" species are part of simply migration and evolution..albeit handily helped by our species..(but then we are part & usual, you are one step ahead..

alotstuff said...

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