Previous Session

Session7: Monitoring and Modelling

Next Session

Chairman: Dr. Rakesh Kumar & Dr. S. Balasubramanyam

Bird Diversity Studies in the Sharavathi River Basin Can They Be Considered as Ecosystem Indicators?

Sudhira H. S. and Ramachandra T. V.


Aquatic and terrestrial conditions combine to form 'wet-lands', one among the most complex ecosystems in the world. The environmental characteristics within a wetland are determined largely by hydrologic processes, which may exhibit daily, seasonal or long-term fluctuations, in relation to regional climate and geographic location of the site. These in turn produce a great range of wetland types globally, majority of which have extremely variable conditions in many habitats, which they contain. As a consequence, the variety of living organisms, adapted to the different wetland habitats tends to be high, with all major groups of plants and animals present. The Convention on Biological Diversity's Article 7 on 'Identification and Monitoring' emphasizes identification and monitoring of components of biological diversity and processes or categories of activities, which have adverse impacts on biological diversity, and maintenance of data derived from these activities. 

The bird diversity study was taken up in the Sharavathi River basin, prone to habitat transformation due to dam construction for hydro-electricity generation. As part of the cumulative impact assessment exercise, a detailed study was undertaken to determine the habitat status. This paper brings out the study on bird diversity estimation in the catchment area. The data collection was done using the line transect method in nine localities of the study area. The localities are classified chiefly as wetlands and terrestrial habitats. Other statistical analyses carried out on the data are presented in the paper.

The study was successful in estimating the diversity index using the Shannon's index as well in finding the evenness of the habitat. An important observation made by the study was that the order Passeriformes dominated the terrestrial habitat. The study also revealed that the wetlands had a better distribution of birds. This could be inferred from the fact that unlike the terrestrial habitat, Passeriformes and Ciconiiformes dominated wetlands, suggesting that these ecosystems have more diversity than terrestrial habitats. During the sampling period, 73 species were identified but a total of 125 species were sighted including opportunistic surveys.  Of the 125 species four are endemics and one endangered species; which is threatened for their survival in the region. In the wake of infrastructure development initiatives in the region the endangered bird species mostly found in the undisturbed evergreen forests is threatened by the loss of habitat. Effective conservation strategies in ensuring the continued survival of the endemic and endangered bird species through ecologically sound development initiatives are to be evolved in this regard. The paper explores the possibility of using bird diversity as an indicator of ecological status.

Address: Energy and Wetlands Research Group,Centre for Ecological Sciences
Indian Institute of Science, Bangalore-12, India
Phone: 080- 3600985 / 3092506
Fax: 91-80-3601428 / 3600085 /3600683{CES-TVR}