Population dynamics of small mammals in an oak woodland-grassland-chaparral habitat mosaic

We present the results of 22 years of snap-trapping sessions in three distinct habitat types (oak woodland valley grassland, and chamise chaparral) in central California. Small mammal abundance in fall, but not summer, generally was correlated positively among habitats (species pooled) and among species (habitats pooled), although most correlations among pairs of species were weak and some were negative. Similarity in temporal patterns of abundance did not correspond closely to similarity in habitat use or to taxonomic affinity. Small mammal abundance in fall (but not summer) also was correlated positively with annual rainfall, but the strength of the relationship varied considerably among species. Species of small mammals in this habitat mosaic formed a loosely-structured assemblage characterized by population dynamics that were primarily individualistic.