IMPACT OF SCRAP PONDS ON THE BIRDS AND FLORA OF CHOLISTAN DESERT

The impact of an anthropogenic wetland created under a salinity control and reclamation project (SCARP) in the arid environment of Cholistan Desert, Province of the Punjab, Pakistan, on the flora and avifauna of the area was examined. Four pond sites of different ages and a reference site were defined and the data on plant and terrestrial bird communities was recorded on the fixed transect lines. The aquatic birds were counted directly on the study ponds during four counting sessions in a period of two years. The count data were analyzed for diversity indices. Indirect and direct gradient analysis using correspondence analysis (CA) and canonical correspondence analysis (CCA) procedures were applied to identify important gradients responsible for shaping plant and animal communities in the area. The most prominent change in the vegetation of the area was indicated by the development of a thick Tamarix dioica ring fringing the evaporation ponds. Plant communities on the sand dunes were found to be less affected. The desert area in periphery of the pond habitat was found to support over 66 species of terrestrial birds with higher richness and diversity close to the ponds as compared to the far areas. In addition to these, 34 species of resident and migratory aquatic birds were found to be regular visitors in the area including some rare species of the region like the Rosy Pelican and the Greater Flamingo. A habitat succession gradient from older to the younger ponds with a low to high salinity was indicated in the SCARP ponds with a complex pattern of habitat use by the aquatic birds. Further, this pond complex was found to act as a useful buffer wetland for the water birds migrating along the Indus Flyway, Flyway-4. The water supply to the ponds needs to be ensured for healthy' ecological functioning of this wetland habitat in the long term.