SLOSS (Single Large or Several Small) or Not? Factoring Wetland Size Into Decisions for Wetland Conservation, Enhancement, Restoration, and Creation

摘要

Mitigation or replacement of several small impacted wetlands or sites with fewer large wetlands can occur deliberately through the application of functional assessment methods (e.g., Adamus 1997) or coinci-dentally as the result of market-based mechanisms for wetland mitigation banking (Bendor et al. 2009). Adoption of the concept that "bigger is better" was influenced by general knowledge of diversity-area curves from island biogeography, minimum area requirements for key species, and the logic that larger wetlands would have a greater capacity for flood reduction and nutrient retention. In the decades since the inception of the SLOSS (single large or several small) nature reserve debates, we have learned more about relationships between wetland area and wetland functions, and how these relationships depend on landscape context, watershed attributes, wetland position, wetland hydrogeomorphic type, specific wetland function, and biotic community type or key species targeted for protection. This overview reviews the current knowledge on these relationships. The discussion articles following this overview will address how these relationships should be factored into assessing wetland conservation successes.