Varied opinions exist as to the species composition and ecological distinction of mangrove habitats of the Indian Sundarbans. Furthermore, distinction of true or major mangroves from mangrove-associate and minor species was left unresolved by past authors. The present study thus aimed to revise a species list of true mangroves in the Indian Sundarbans delta. An indexing of adaptive morpho-physiological characters of mangroves for the tidal-saline environment was conducted. The analysis illustrated 24 species of true mangroves in Indian Sundarbans, belonging to nine families. Of these, Rhizophoraceae showed maximum richness at each of the generic and specific categories assessed. The current study has highlighted the taxonomic richness and status of true mangrove from Indian Sundarbans, resolving the long debated distinction of true from minor and associate mangroves.

East Calcutta Wetlands (ECW), lying east of the city of Kolkata (formerly Calcutta), West Bengal in India, demonstrates the usage of city sewage for traditional practices of fisheries and agriculture. As a Ramsar Site, the wetland demands exploration of its bioresources for better understanding and management of the ecosystem operating therein. Butterflies (Lepidoptera: Rhopalocera) being potent pollinators and ecological indicators, are examined in the present study. The diversity study, conducted for two consecutive years (Jan. 2007-Nov. 2009) in all the three seasons (pre-monsoon, monsoon and post-monsoon), revealed seventy-four species. As butterflies depend on preferred host and nectar plants during their larval and adult stages respectively, the lack of these sources in some parts of ECW indicate degraded habitats with low species richness. Ongoing unplanned anthropogenic activities like habitat modifications (conversion of wetlands to agricultural lands) are resulting in the loss of wetland biodiversity and hence ecosystem integrity in ECW.

Competing Interest: The author declares to have financial support from the Centre for Biodiversity and Ecological Studies (CBES) for the submitted work, and no other relationships or activities that have inspired the same.Author Details: Dr. Soumyajit Chowdhury is a faculty member of the Department of Zoology, V.J.R. College, Kolkata and founder member of Centre for Biodiversity and Ecological Studies (CBES). He has been working on the biodiversity and ecology of Indian insects and authored several research articles. He also initiated 'BIOME india', an online resource on the ecosystem-based conservation programmes of India. Acknowledgement:The author is indebted to the Centre for Biodiversity and Ecological Studies for supporting, in part, the survey work on lepidopteran fauna and different mangrove and mangrove-associated floral components in Indian Sundarbans. Nihar Mondal, Tanmoy Mondal and Amit Das among several others deserve special thanks for logistic support during field trips in different parts of central, western and eastern Sundarbans. Abstract:The Indian Sundarbans, part of the globally famous deltaic eco-region, is little-studied for butterfly diversity and ecology. The present study reports 76 butterfly species belonging to five families, which is a culmination of 73 species obtained from surveys conducted over a period of three years (2009)(2010)(2011) in reclaimed and mangrove forested areas and three species obtained from an earlier report. Six of these species are legally protected under the Indian Wildlife (Protection) Act, 1972. Random surveys were employed for both the study areas, supplemented by systematic sampling in reclaimed areas. The reclaimed and forested areas differed largely in butterfly richness (Whittaker's measure of β diversity = 0.55). For sample-based rarefaction curves, butterfly genera showed a tendency to reach an asymptote sooner than the species. Numerous monospecific genera (77.19% of the taxa) resulted in a very gentle but non-linear positive slope for the species-genus ratio curve. A species-genus ratio of 1.33 indicated strong intra-generic competition for the butterflies of the Indian Sundarbans. Mangrove areas were species poor, with rare species like Euploea crameri, Colotis amata and Idea agamarshchana being recorded in the mangrove area; while Danaus genutia was found to be the most frequent butterfly. Butterfly abundance was very poor, with no endemic species and the majority (53.9% of the taxa; n=41) were found locally rare. The changing composition of butterflies in the once species-poor mangrove zone of the fragile Sundarbans may interfere with their normal ecosystem functioning.

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