Relative abundance and diversity of waterbirds in a Persian Gulf mangrove forest, Iran

Abstract

Mangrove habitats are host to many waterbirds around the globe. However, the roles of mangrove habitat structures in association with variation in individuals and their community of waterbirds have not been examined in detail. The objective of this study was to determine the abundance, diversity and evenness of waterbirds in an Avicennia mangrove habitat. The study was conducted using a point count method at Hara Protected Area (HPA) in Iran for 1 year. A total of 59,387 waterbirds observations, belonging to 56 species, were recorded and categorized based on different seasons, where 13,825 (49 spp.), 34,267 (54 spp.), 6939 (46 spp.) and 4356 (35 spp.) observations were recorded in the different seasons of fall, winter, spring and summer respectively. In total, 80.98% of individual observations had occurred during the migratory season. Dromas ardeola (11,329 observation; 19.08%) and Calidris alpina (5261 observation; 8.86%) were the most abundant, while three species including Phalacrocorax nigrogularis (4 observations), Vanellus indicus (2 observations) and Chlidonias leucopterus (2 observations) were the least abundant waders and seabird species. There were significant differences between the number of waders and seabirds observed in fall (t = 1.22, P < 0.05), winter (t = 1.27, P < 0.05), spring (t = -0.78, P < 0.05) and summer (t = -1.55, P < 0.05). The results also showed that there was a significant difference between the number of individuals observed in different seasons (F3,232 = 7.4, P < 0.01). The abundance of waterbirds at HPA was highest in winter while the diversity and evenness were highest in spring. The HPA is important because of the presence of exotic species such as Numenius arquata that is listed as near threatened in the red list of the International Union for Conservation of Nature. HPA mangrove forest could be one of the "megadiversity" places in the Middle East. Thus, preventing further losses of the mangrove and reducing the impacts of disturbance on birds and their habitats should be prioritized. © Istituto per lo Studio degli Ecosistemi of the Consiglio Nazionale delle Ricerche, Firenze 2012.