Rodent response to habitat fragmentation in a sand dune complex

As habitat restoration becomes an increasingly important tool for conservation, understanding the effects of restoration on mammals should also become increasingly important. Anthropogenic changes in vegetation impact the structure of rodent communities; identifying these impacts will aid conservation practices. Live trapping (2,645 trap nights) was conducted on the naturally fragmented sand dune habitat in Oceano, central California. Little was known about the structure or the spatial distribution of the rodent community in the dune system. The dunes have two distinct habitat types: isolated islands of vegetation in a sea of sand and vegetation areas that link with surrounding habitats beyond the dunes. Isolated populations had lower abundance but greater diversity in both the plant (22 species on islands; 17 species on mainland) and rodent (6 species on islands; 4 species on mainland) communities. Regression analyses showed that island size had a significant effect on rodent diversity but the island's distance had only a marginal impact, and shape also affects community structure. Thus to encourage rodent populations during restoration work, islands should be formed on Barchan dunes with areas greater than 134 m2. These islands should also be formed in close proximity (<150 m) to the mainland in order to encourage greater diversity of rodent populations.