Biodiversity and biogeography pattern of benthic communities in the coastal basins of India

ABSTRACT

Our understanding of coastal biogeography patterns is presently limited to certain regions and marine groups. Comprehending large-scale patterns and their underlying predictors is critical due to the changing environmental conditions. The Indian coast, bounded by two contrasting seas, the Bay of Bengal and Arabian Sea, offers an excellent opportunity to determine the most important factors influencing coastal biogeography patterns. Here we use distribution data of 2581 species belonging to three benthic groups (polychaetes, gastropods and bivalves) to evaluate the role of environmental factors and coastal currents on the biogeography patterns. Data were obtained from the bioSearch database, developed by CSIR-NIO, Goa under the Census of Marine Life programme. As measures of diversity, we used species richness as well as taxonomic distinctiveness indices. Multivariate analyses were used in identifying biodiversity patterns and correlated biogeography patterns with environmental factors. This paper points out a clear difference between the eastern and western basins of India, but also within the basins. Mainland and island fauna also showed a clear distinction. The biogeography of the Indian coast is best explained by temperature, habitat heterogeneity and coastline length. Spatiotemporal variability in the boundary currents also forms an effective barrier for the dispersal of planktonic larvae of benthic fauna. This study has identified a finer scale division of the Indian coast that can help to effectively improve conservation plans. Our study is the first to attempt to understand the benthic biogeography patterns of the Indian coast. The findings will be useful in guiding future biogeography studies of this unique and underexplored marine system.

RESPONSIBLE EDITOR:

• Dan Smale

KEYWORDS:

• Benthos
• biogeography
• coastal currents
• diversity
• environmental factors
• habitat heterogeneity

Acknowledgements

We are grateful to the Director, CSIR-National Institute of Oceanography for the use of facilities. We also appreciate the efforts of Mr Devanad Kavlekar, MSc and the PhD graduate students for helping with the compilation of the bioSearch database. We are thankful for the supportive discussions with Dr Anup R. Gujar, Dr Pratima Kesarkar (Geology), Dr Shankar Doraiswamy, Arnab Mukherjee and P. Amol (Physical Oceanography). The manuscript was significantly improved by the comments of the anonymous reviewers. We thank Miss Lakshmi Priya M. for the language editing of the manuscript. This is contribution number 5899 of CSIR-NIO, Goa.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The first author is supported by a CSIR Research Associate and SERB-National Post Doctoral Fellowship (Project no. SR/FTP/ES-18/2012). We acknowledge the support and facilities received from the Govt. of India under CSIR (PSC0206) and DBT (GAP0423) projects.