Distribution and Temporal Trends of Western Reef Heron (Egretta gularis) Populations along the Arabian Gulf Coast of Abu Dhabi, United Arab Emirates

The Arabian Gulf Coast of Abu Dhabi, United Arab Emirates, consists of highly productive seagrass (Halodule universis, Halophila ovalis and Halophila stripulacea) and mangrove (Avicennia marina) habitats that are essential breeding and non-breeding areas for vast numbers of waterbirds. Due to their dependence on these coastal habitats, waterbirds such as the Western Reef Heron (Egretta gularis) can act as important bioindicators of ecosystem health. The estimated global population size of Western Reef Herons is roughly 10,000 to 100,000 individuals. While populations are currently considered stable, many important breeding and overwintering areas of the Western Reef Heron remain unprotected. Line transect counts were conducted at study sites along the Arabian Gulf Coast of Abu Dhabi monthly throughout 2006-2015. Using a mixed effects model, it was found that both year (F1, 1132 = 29.15; P = < 0.001) and month (F11, 1132 = 2.32; P = 0. 011) had significant influences on the number of birds counted at any given site; however, there was no statistically significant interaction between year and month (F11,1132 = 1.24; P = 0.253). While there was an overall non-significant decrease in counts across years (t495 = -1.40; P = 0.163), there were significant inverse relationships between year and count at the Al Aryam (t485 = -13.55; P = < 0.001) and Abu Al Abyad (t485 = -2.23; P = 0.026) sites, suggesting annual relative abundance is declining in these areas. Further research and monitoring of the Abu Dhabi Western Reef Heron population is recommended due to continued destruction and degradation of critical waterbird habitat.