Changes in the diversity and ‎abundance of wintering ‎waterbirds within protected areas ‎in Anzali International Wetland ‎complex

Waterbirds are among the most vulnerable species of birds, and their species richness and population size are important indicators of the quality and conservation value of aquatic ecosystems. The populations of waterbirds are severely in decline, and in recent years more species have been added to the IUCN Red List. It is therefore imperative that the populations of these birds be monitored and protected. The purpose of the present study was to investigate the trends in the diversity and density of wintering migratory waterbirds in four protected areas in the Anzali International Wetland Complex, namely Selkeh, Sorkhankol, Choukam and Siahkieshim. To this end, data from the mid-winter census during a 10-year period (2003-2005 and 2008-2013) were used. We also compared the similarity of waterbird communities among the four protected areas using the Morista Index and PCA test. In total, 65 species of waterbirds were identified in all of these four areas of the wetland. Selkeh had the highest species richness (57 species) and Siahkeshim had the highest mean abundance (31,504 individuals). Also the highest abundance of these four areas combined was in 2013 (103,332 individuals) and the lowest was in 2005 (42,842 individuals). Anatidae were represented by the highest number of species (18 species) and Threskiornithidae and Sternidae families were lowest with one species each. The results of Morista Index and PCA test also revealed that, Sorkhankol wildlife refuge had the least similarity with the other protected areas based on species richness. The results suggest the importance of the Sorkhankol area for providing habitats and supporting diving waterbird species, in particular its value for diving ducks. So, this part of Anzali Wetland may need to be protected more than before. Implementation of comprehensive wetland management plans and establishment of integrated ecosystem management systems are among the most important strategies for preserving these four areas for aquatic birds and overwintering.