Abstract
Biodiversity in communities is affected by a host of ecological processes, including climate. Human activities, such as land-use, also have many effects on a wide range of ecosystems, including wetlands. Land-use, in tandem with climate, can reduce and greatly alter habitat but is understudied in temporary wetlands. Vernal pools are temporary, freshwater wetlands that occur in the Central Valley of California and in other Mediterranean climates. They support high levels of endemism and many threatened or endangered species, but only 10% of this habitat remains in California. This study used two previously collected vernal pool datasets to understand how surrounding land-use, climate variables, and pool size influence species diversity of different vernal pool taxonomic and functional groups. Land-use/land-cover data from the Multi-Resolution Land Characteristics Consortium National Land Cover Dataset was used to determine the amount of different types of human land-use in a 1km radius circle surrounding vernal pools. Vernal pool plants had significant relationships with all three sets of variables while vernal pool animals had significant relationships with only the pool size variables. Measures of plant diversity generally increased with latitude and with measures of pool size and decreased with the amount of developed land. Measures of animal diversity generally increased with measures of pool size. Many of these relationships appear to be driven by functional groups, specifically by native plant species or by passive dispersing animal species. This study highlights that pool size is one of the major factors that drives diversity in vernal pools. Any factor that changes pool size (encroaching anthropogenic land-use, changes in inundation duration due to changes in climate, etc.) will impact diversity. This study also demonstrates the need to focus on site level restoration instead of restoration at the individual pool level.