Sunday, December 13, 2009

Climate change & invasive species

Climate change and invasive species are interconnected challenges global in impact and reach. Invasive species are those species which have moved from their native recorded ranges to new ecological systems where for any number of reasons they flourish, many times at the expense of the indigenous species. A major factor that enables a non native species to survive and expand successfully is the climate of the new ecosystem. This climate factor is the same one that supports the established species ability to thrive. Natural ecosystems are value neutral and climate dependent.

An ecological system also known as an ecosystem provides resources such as atmospheric gas regulation, erosion control, storm water management, genetic diversity, biological habitat and refugia, food, feed, fuel, fiber, flowers and forests, as well as aesthetic, human health and recreational services. The ecosystem is a complex web of complicated interaction between species with many scales of time and size interacting simultaneously. From virus and bacteria to charismatic mega flora (redwood) and fauna (condors), ecosystems provide renewable resources if not over-harvested or stressed by ecosystem service imbalances.

The complex interactions of system species with their environment constitute a dynamic feedback system. Each component or part of the system “tries” to maximize its use of resources. The result is a dynamic and moving middle-point of balanced forces. When the balance of the whole system is altered the system readjusts. The readjustment does not return exactly to the past state and in extreme or drastic conditions, resets into a new system passing through a collapse of resource services.

Climate change as change of any process in an ecological system is self regulating over time. A system is adapted to changes in climate that are incorporated in to the feedback connections. The whole system changes together in time and through time. When climate change comes faster its impact in the whole system is greater and takes place more quickly. Climate is a pattern of weather over time. When the function of climate changes over a smaller period of time it begins to resemble weather, and the probable patterns of climate begin to disappear replaced by greater randomness or inability to allocate resources in anticipation. The various species adapted to specific climate needs are stressed sometimes to the point of extinction while species with greater climatic adaptability weather the change.

When a species is moved from its native range into a new ecosystem where among other factors climate conditions are favorable, it may begin to establish, compete and spread. If the species is climate adaptable and the climate is changing rapidly, the species begins to impact the current expect resource services. The new species may crowd out native species reducing diversity; they may reduce harvests of natural resources such as timber and food, and even may obstruct storm management processes thereby allowing greater damage from floods. The impact of the new species, the invasive species, may be measured as a reduction (increase) of endogenous resource services. The impact of climate change may also be measured as a reduction (increase) of existing ecosystem resource services. A change in ecosystem services measures the impact of invasive species on an ecosystem. A change in ecosystem services is also a measurement of the impact of the change in time of climate type.

As weather defines, over time, a climate pattern, invasive species, over time, define an ecosystem. This level of complexity creates unintended consequences when definitions are simplified and when short term solutions are sought. Banning an exotic pest, plant or animal is a cost effective mechanism for stopping invasion to save a natural area ecosystem, but the climate can not be interdicted so easily and in periods of quick change will radically altered what is native or indigenous. Solutions formulated as simplified absolutes will get action, attention and movement, but are in themselves one of many possible answers.

Climates are impacted by ecosystems which are changed by invasive species that are impacted by climate. Addressing concerns in one with out addressing concerns in all is short term recourse to futility. Rather we must manage the entire system or be managed by it. For ease and peace of mind we create environmental sets with hard edges and give them labels. In doing so we tend sometimes to forget that the now separate pieces are all part of the same set or system: species, climate, and environment are all arts of the same grand Terran biome, our home, Earth.

Because invasive species are climate dependent and both invasive species and climate impact ecosystems we have both a fuzzy problem and a wicked problem. The wicked inconvenience of invasive species and climate change’s inconvenient truth are sets of problems with much in common. Both have multiple stakeholders so confused by the infinite possibilities that they define the problems based upon their desired outcomes. Both problems are non linear, but the stakeholders claim absolute truths anyway and put forward logical absolutes in attempts to buttress their a priori claims. The two problems have no end except when resources are exhausted or political will ends. In addition, and most importantly, the two issues have co-equal, co-evolving problems with which they are intrinsically related which are: each other.

No comments: