Waterbird community responses to anthropogenic land cover at multiple
spatial scales along the Nile in Egypt
Abstract
The human population is growing rapidly, increasing pressure on natural
habitats. Suitable habitats for resident and migratory waterbirds are,
therefore, more threatened. This study analyses how the presence of
anthropogenic land cover (urban area and cropland) on multiple spatial
scales affects the community composition of waterbirds along the Nile in
Egypt. We analysed data collected during the international waterbird
census, 2017-2018, combined with data from satellite images on land
cover at a multi-spatial scale. The census covered 970 km, compromising
194 shoreline transects of 5 km along the River Nile, Egypt. The area
includes a broad gradient of human disturbance, making this dataset
ideal for assessing effects of anthropogenic land cover on waterbird
community composition. We tested whether the waterbird community indices
and guild composition were associated with urban area and cropland, and
other land covers (e.g., grassland, wetland) at spatial scales of 100,
500, 1,000 and 5,000 m. We recorded over 96,000 waterbirds and show that
landscape characteristics at larger spatial scales (5,000 m) explained
more of the species and guilds’ presence than smaller scales. Species
richness increased with increasing water surface area of the river
within the transect and decreased with increasing urban area and
cropland. Waders were negatively associated with urban area. Overall,
the guilds’ composition was poorly predicted by anthropogenic land cover
and other landscape compositions, probably because species within a
guild do not react similarly to increasing human disturbance. The
probability of observing red-listed species decreased with increasing
urban area. With this study, we expand on the existing evidence by
showing that species richness negatively correlates with anthropogenic
pressure, and we highlight the importance of studying the responses of
species rather than guilds. Our study shows the relevance of considering
the landscape at larger scales while planning for conservation measures,
especially in such human-dominated landscapes.