Spatial patterns of breeding colonies of Great Cormorant (Phalacrocorax carbo) and Palas's Gull (Larus ichthyaetus) on Kitay Island in the Central Sivash lagoon system

This study analyzes the spatial distribution patterns of breeding colonies of Great Cormorants (Phalacrocorax carbo) and Palas’s Gull (Larus ichthyaetus) on Kitay Island in the Central Sivash lagoon system. Using spatial point pattern analyses, we quantified clustering and dispersion at multiple spatial scales. Our results reveal a marked contrast in nesting strategies: Great Cormorant nests exhibited strong, statistically significant clustering (mean Nearest Neighbor Distance, NND = 0.23 m; Moran's I = 0.34, p = 0.02) and significant positive spatial autocorrelation, consistent with colonial breeding. In contrast, Palas’s Gull nests were significantly more dispersed (mean NND = 0.67 m) and showed no significant spatial autocorrelation, reflecting territorial nesting behavior. Cross-species analysis indicated moderate spatial segregation, evidenced by a negative correlation of nest densities (r = -0.56) and Ripley's cross K-function, suggesting niche partitioning that facilitates coexistence. These findings quantitatively highlight distinct nesting ecologies and emphasize the critical importance of integrating spatial ecology into conservation planning for colonial waterbirds in saline lagoon islands. The study provides new quantitative baselines crucial for effective monitoring and habitat management in the Azov-Black Sea region.