Plant and Small Vertebrate Composition and Diversity 36–39 Years After Root Plowing

Abstract

Root plowing is a common management practice to reduce woody vegetation and increase herbaceous forage for livestock on
rangelands. Our objective was to test the hypotheses that four decades after sites are root plowed they have 1) lower plant
species diversity, less heterogeneity, greater percent canopy cover of exotic grasses; and 2) lower abundance and diversity of
amphibians, reptiles, and small mammals, compared to sites that were not disturbed by root plowing. Pairs of 4-ha sites were
selected for sampling: in each pair of sites, one was root plowed in 1965 and another was not disturbed by root plowing
(untreated). We estimated canopy cover of woody and herbaceous vegetation during summer 2003 and canopy cover of
herbaceous vegetation during spring 2004. We trapped small mammals and herpetofauna in pitfall traps during late spring and
summer 2001–2004. Species diversity and richness of woody plants were less on root-plowed than on untreated sites; however,
herbaceous plant and animal species did not differ greatly between treatments. Evenness of woody vegetation was less on rootplowed
sites, in part because woody legumes were more abundant. Abundance of small mammals and herpetofauna varied with
annual rainfall more than it varied with root plowing. Although structural differences existed between vegetation communities,
secondary succession of vegetation reestablishing after root plowing appears to be leading to convergence in plant and small
animal species composition with untreated sites.

Key Words: amphibians, brush management, Prosopis glandulosa, reptiles, rodents, woody plants