Understanding arid‐region waterbird community dynamics during lake dry‐downs

These data were collected to explore changes in the bird community
associated with Lake Ngami, Botswana, through successive drydown periods.
Our analysis shows significant shifts, driven partially by changes in
water level, in the species composition of the bird community over the
period of study. The data set contains standardised
half-hour point counts for the bird community of Lake Ngami, Botswana; and
R code used for community-level analyses of the resulting time series.
Counts were undertaken every 4 months from October 2007-July
2009. We used the data to test three theoretical predictions:
simplification of the bird community over time due to a reduction in
habitat area and concurrent niche loss; large fluctuations in densities of
mobile, opportunistic species; and high variance in predator and prey
abundance. Despite temporal variance in species accumulation, we observed
no obvious simplification of the bird community over time. There were
distinct but consistent groupings of abundance and composition across
transitional stages in lake water levels. The data do show some
rapid shifts in functional composition, such as loss of deepwater
foragers; winners and losers also occurred within foraging guilds.