ECOLOGICAL SUITABILITY AND TEMPORAL ANALYSIS OF UCHALLI LAKE FOR WHITE HEADED DUCK

Abstract

White headed duck is a migratory waterfowl inhabiting the Ucchali Lake during winter season. Its rapidly declining global population has made it a species of concern for the ecologists. The present study was undertaken to assess the ecological suitability of Ucchali Lake (Ramsar site) for the endangered white headed duck. The specific objectives of the study were to evaluate the impact of land use land cover dynamics on white headed duck‟s population and temporal assessment of Ucchali Lake water quality for duck‟s suitability. Multi date and multi spectral satellite imagery was used for land use land cover change detection. Vegetation was considered a surrogate variable for duck's winter food availability to assess suitable habitat using habitat suitability index model. Regression analysis was applied to establish relationship between annual vegetation cover and duck‟s population for the study period. Selected water quality parameters (pH, temperature, electrical conductivity, phosphates, dissolved oxygen, total dissolved solids, nitrates, secchi depth transparency and trophic state index) were analyzed to assess lake‟s supportability for aquatic life. The results of the study suggested that lake‟s varying landscape has altogether altered the ecology of the area; decreasing overall suitable habitat from 64.9% to 40.2%. A significant positive relationship was observed between vegetation cover and duck‟s population (r² = 0.363, p = 0.043). The degrading water quality and rising eutrophication level (dissolved nitrates and phosphates) had possibly a negative impact upon inhabiting water fowl population, particularly white headed duck. The study recommends constant monitoring of Ucchali Lake for proficient restoration and management of declining population and degrading landscape ecology.