Wildlife Association with Human-Altered Water Sources in Semiarid Vegetation Communities

Based on common use in wildlife management, we hypothesized that human-constructed water sources influence faunal communities detectably compared to similar habitats that lack water. We examined 20 wildlife water units and 20 paired comparison sites without water from April to August 1992 in semiarid southern New Mexico to assess animal species associations. We sampled sites by using small-mammal live traps, herpetofaunal and invertebrate pitfall arrays, and 30-minute time-area counts. We compared animal species richness and species concordance among water units (rain catchments, earthen tanks, and windmills) and comparison sites in three vegetation communities (mixed scrub, grassland, and pinyon-juniper). We detected 134 animal taxa during field sampling. Animal species richness did not differ between water units and comparison sites among vegetation communities. Amphibians were found only at water units but occur far from units during seasonal wet periods. Greater numbers of individual small mammals and herpetofauna at water units versus comparison sites likely related to debris and disturbed soil present near water units. Taxa detected at water units and comparison sites were 65% concordant overall; discordant taxa were those rarely detected. Our data implied that definitive effects of artificial water sources on native wildlife species were not detectable. Providing water sources may be a strategic management tool but must be viewed critically regarding effect on distribution of native, feral, and exotic animals. Water units should be developed only when and where clear objectives have been stated, natural water sources have been quantified, commitment exists to ensure continued function, and feral and exotic animals will not benefit to the detriment of native species.