Temporal changes in a Chihuahuan Desert rodent community

Used time series analysis of 10 yr of monthly census data to assess the responses of both individual species and an entire community of rodents to a fluctuating desert environment. Dipodomys spectabilis and Perognathus flavus had pronounced annual cycles; D. ordii, D. merriami, Chaetodipus penicillatus, Onychomys torridus, O. leucogaster and Neotoma albigula exhibited annual cycles modified by interannual variation; and Peromyscus eremicus, Pm. maniculatus and Reithrodontomys megalotis showed little evidence of annual periodicity. Timing of annual cycles and the pattern of inter-annual fluctuations also differed among species, but 2 results that several species responded similarly to long-term environmental variation: 1) population densities of 4 species and total rodent biomass and numbers were positively correlated with the densities of annual plants; and 2) many pairs of species exhibited positively correlated population dynamics. Clustering of pairwise cross-correlation coefficients was used to identify sets of species with similar population dynamics. Detrended Correspondence Analysis identified 3 independent patterns of variation in species composition: a long-term trend; a 4-5 yr repeated pattern that appeared to correspond to the climatic effects of the El Nino Southern Oscillation; and an annual cycle. In general, species appeared to respond individualistically to environmental variation. -from Authors