RODENT COMMUNITIES OF NATIVE WOODLAND, REPLANTED, AND SECONDARY SUCCESSION SITES IN THE LOWER RIO GRANDE VALLEY, TEXAS

摘要

Wildlife habitat is rapidly disappearing in the Lower Rio Grande Valley of Texas and is in critical need of protection. United States Fish and Wildlife Service plans call for protection of 53,420 ha in the area, with the Rio Grande serving as the major corridor linking tracts of native and restored vegetation. Species richness, diversity, density, biomass and similarity of rodent communities were compared among a native woodland, a replanted field, and an unaided secondary succession site to obtain information on the efficacy of vegetation efforts in promoting rodent community diversity. Species diversity varied from H' = 0.0 to 0.65 depending on habitat, grid and season. Species richness ranged from 5 to 9 among the three habitats and a total of 10 species was captured. Density for all species combined ranged from 269 to 388 rodents/ha. Sigmodon hispidus, Peromyscus leucopus, and Liomys irroratus were the most abundant rodents in the native woodland and replanted habitats where they together comprised 88% and 90%, respectively, of the individuals captured. Mus musculus replaced P. leucopus in abundance in the unaided succession habitat. Biomass was greatest where S. hispidus was most abundant. Community similarity was greater between the two successional habitats than either was to the native woodland. The native woodland had fewer species but greater evenness than either successional habitat. The replanting technique used by the United States Fish and Wildlife Service in a formerly cultivated field produced greater diversity of rodents in less time than unaided secondary succession of a fallow field. Variation in application of planting techniques can produce significant differences in vegetation and rodent communities on small replanted areas.