Abstract
The Karachi Western Backwaters lie behind the sandy stretch of the Sandspit and Hawkes Bay beaches. Sea water enters the lagoon via Manora Channel, while the Lyari River falls on the eastern-northeastern side of the lagoon. Mangrove forest exists on 400 to 500 hectares of the swamps in the lagoon, traversed by a main channel and its branches. This forest is an important wintering ground for a large number of migratory birds coming from Siberia, Central Asia, Europe, and Pakistan’s own high altitude cold areas. A thorough study of the flora, vegetation, and the Avifauna associated with this mangrove forest was done for the first time. Complete inventories of plant species and bird species were prepared, while the bird populations were monthly monitored for six years from 2005 to 2010. A total of 58 plant species were recorded that were present in four types of microhabitats, ranging from the coastal wet and saline soil to the intertidal zone in the mangrove swamps (including the sole mangrove species Avicennia marina) to somewhat higher dry sandy and rocky land around the mangrove ecosystem. The total recorded bird species were 96, out of which 58 were migratory and 38 were resident species. Over the study years both the number of bird species and total number of individuals continued to decrease. By the end of the study, 14 migratory birds totally disappeared. These were in addition to those 25 migratory species that were not found altogether in the present study but were reported in a previous work shortly before the commencement of the present study. This trend indicates that this area is fast becoming unfavourable for the migratory bird species. The possible causes include pollution, continually increasing anthropogenic disturbances and increasing human presence in the area. This important ecosystem is in dire need of immediate conservation measures.
