The presence of artificial water points structures an arid-zone avian community over small spatial scales

Abstract

Water plays a key role in avian thermoregulation, especially when environmental temperatures approach or exceed body temperature. Birds living in arid environments need to either be adapted to life with unreliable access to water, or engage in large-scale movements to access water. This study asked whether species richness and the distribution of bird species in the Kalahari landscape across scales of kilometres is predicted by the availability of open water sources. We conducted point count surveys for birds and modelled these as a function of habitat variables and distance to the nearest water source. We recorded 52 species during our point counts. Despite much variation in species richness scores at each point, species richness decreased with increasing distance from water. Granivorous birds were most dependent on water and showed higher probability of occurrence closer to water. Vegetation height impacted detectability for seven species, negatively for four and significantly positively for two. The provisioning of artificial water in the Kalahari is likely facilitating the presence and abundance of some bird species, notably seed eaters. Communities of birds will likely change if water points are closed or water becomes scarcer under climate change, which could well alter the ecosystem functioning of these regions.

Keywords: air temperature, birds, climate change, distance, occupancy modelling, point count, surface water, water