Significant Impacts of the Water Level and Human Intervention on the Natural Habitats and Breeding Waterbirds in Marmara Lake

Habitat cover and change were analysed in the Marmara Lake to investigate the effects of water level and human intervention on the natural habitats and breeding waterbirds. Breeding Birds Surveys were applied to investigate breeding waterbirds and their breeding activities in 2008 and 2011. GIS, remote sensing techniques and various satellite images were used to determine distributions, surface areas, zonal centroids, and displacements of the habitats in 2000, 2008 and 2011. The total number of bird species with and without breeding evidence in 2008 and 2011 were compared with the Chi-Square test. Habitats in each UTM grid in 2008 and 2011 were compared with McNemar’s test. The impact of water level on habitats, number of breeding birds, and their breeding parameters were investigated using Spearman’s correlation analyses. The major habitats were open waters, reed beds, scrubs and woodlands, wet grasslands, and mudflats. Significant increases were observed in open waters, reed beds, and wet grasslands, but no significant change was observed for scrubs and woodlands. Out of 70 UTM grids, 69 and 48 grids corresponding to 95 and 75 observation points were surveyed in 2008 and 2011, and 34 different waterbirds were identified. The total number of breeding waterbirds significantly increased in 2011. Open waters were positively correlated with reed beds and negatively correlated with mudflats. Among 34 waterbird species, changes in the breeding parameters of 22 species were significantly correlated with the changes occurring in the major habitats. Our study demonstrates that changes in water level significantly affected the existence of key habitats and theirs distributions, resulting in significant changes in the number of breeding waterbirds and their breeding activities.