Impact of habitat loss on Dalmatian pelican breeding colonies

Abstract

The Dalmatian pelican, classified as Near-threatened, depends on T & uuml;rkiye for around 10% of its global population. The Gediz Delta is crucial, serving as one of the nation's five key breeding sites. Homa Lagoon historically supported significant pelican populations; however, its islands have faced an 80% reduction in area since 1999 due to soil erosion and rising water levels. In 2022, Lake Marmara experienced complete desiccation, further exacerbating habitat loss. This study assesses trends in Dalmatian pelican breeding pairs and evaluates the impacts of habitat loss in Homa Lagoon and the drying of Lake Marmara. Monitoring from 2016 to 2023 revealed a decline, with an average of 130 breeding pairs across the Gediz Delta, dropping from 183 in 2017 to 117 in 2023, and zero pairs on Homa Lagoon islands in 2022. In response, pelicans shifted their breeding to an artificial island and coastal marshes. Initially, a negative correlation was observed between island area and pelican pairs (r = -0.60) from 2002 to 2017, shifting to a non-significant but positive correlation (r = 0.26) by 2023, reflecting the impact of continued habitat contraction. The loss of surface area in Lake Marmara also significantly affected breeding numbers, highlighting its critical role as a foraging ground, especially post-2013. These findings underscore the urgent need for long-term monitoring, wetland conservation and restoration to support pelican breeding colonies.