Can bird atlas data be used to estimate population size? A case study using Namibian endemics

摘要: Abstract An assessment of population size is a fundamental stage in the conservation any species. The recent availability data from Southern African Bird Atlas Project (SABAP) provides tool to investigate status and distribution approximately 900 bird species covered by this work. It often assumed, but rarely shown, that atlas reporting rates provide measure relative abundance. Here, we go one step further assess whether or not rate can be used establish absolute abundance thereby produce estimates size. To do so, must consistent relationships between densities samples throughout species' range, then extrapolate those all areas where occurs. Field transects were undertaken austral winter 1993, across distributions most near-endemic birds north-western Namibia. Density values obtained main riverine upland zones inhabited these combination with Geographic Information System (GIS) overlays three spatial layers (vegetation, altitude rainfall) for each sampled square. relationship was investigated using log-linear regression four differing habitat specialisation. We found significant ( p = 0·051) fourth, cryptic, conclude give reasonable some species, careful consideration given factors such as field sampling effort, detail GIS particularly quality original data.