PARENT SESSION
Symposium #3: The role of spatial extent in ecological pattern and process.
Sponsored by ESA Vegetation Section
Organized by: J. Nekola and H.H. Wagner.
Monday, August 6, 2001. 8:00 AM to 11:45 AM. Madison Ballroom B
Extent and conservation biology .
WHITE, PETER1, 1
ABSTRACT- Explanations of the distribution of living things rest on two conceptual pillars, the niche difference model and the model of spatial and temporal constraint. Both of these models suggest the importance of spatial distance as a simple correlate of biological pattern and process. I discuss five seemingly disparate issues whose resolution derives from a consideration of spatial extent. The Single Large or Several Small (SLOSS) debate, laid to rest and resurrected many times, can never be resolved because grain and extent maximize different aspects of factors that control the distribution of biological diversity. The distance over which species are moved is one risk factor in the introduction of invasive alien species. The risk of gene movement to fitness will also likely show a strong relationship to the distance moved, being highest at short and long distances for outcrossing species. Lastly, the relevance of reference site data in ecological restoration decreases as the distance between reference sites and target communities increases. Processes that are spatially constrained (dispersal and gene flow) are as fundamental to understanding pattern and process as the physiological abilities of species and their interaction with the physical environment.
KEY WORDS: Grain, Extent, biological diversity, conservation