Sevilleta LTER

Credit: Jeff Schmaltz; MODIS team; NASA, Posted on: Wednesday, 16 November 2005, 06:09 CST Download full size image

Located approximately in the center of this image is the Sevilleta Long Term Ecological Research center. Its mission is "To understand how abiotic drivers and constraints affect dynamics and stability in an aridland ecosystem".

Abiotic refers to the non-living portion of the biosphere, and can include temperature and precipitation. A driver in this sense means a major influence or cause, while constraints refer to how the non-living realm provides limits or boundaries on living organisms.

Dynamics and stability refer to change; since temperature and precipitation have such a strong impact on what vegetation can and does survive in the region (and plants are the base of the food web for other organisms), understanding how changes in climate affect other parts of the ecosystem is very important.

Changes are not one way; instead, they can act as feedback loops. A positive feedback loop means that a change in one part of the system causes a change in another part that tends to amplify the magnitude of the change, while a negative feedback loop causes a change in another part of the system that tends to dampen, or diminish the change.

A very simple example of a positive feedback loop this particular part of the world could be as follows: global warming could alter the water balance, reducing precipitation, which would make the area less hospitable for plants. Fewer plants would mean more soil erosion, which means less water available for plants, and so on.

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