A habitat-based plant diversity assessment was carried out in order to appraise the current status of the mangroves of Thane creek (Maharashtra, India) for appropriate measures for conservation of the fragile ecosystem. `Partially protected' and `disturbed' are the two major categories of habitat recognized during the study. In addition, mangrove vegetation of each habitat is quantitatively analyzed for its diversity (species richness and distribution) and growth parameters (above ground biomass). Habitat is found to be responsible for the physicochemical setup of mangrove swamps, which decides a community pattern in mangroves. Out of the 18 species recorded from the Maharashtra coast, Thane creek exhibits eight mangroves, viz., Avicennia marina Vahl., Avicennia officinalis L., Bruguiera cylindrica Bl., Sonneratia apetala Buch.-Ham., Ceriops tagal Robin, Excoecaria agallocha L., Acanthus ilicifolius L. and Aegiceras corniculatum Blanco. No zonation pattern could be recognized within the present day mangrove forest. In general, the vegetation is dominated by Avicennia marina, which has an ecologically successful Importance Value Index (IVI) of 157.29 and is most resistant to biotic and abiotic stresses, while others are susceptible to environmental stress and gradually shrink. The results exhibited significant diversity and distribution in partially protected areas. In severely degraded areas, A. ilicifolius grows in abundance, indicating secondary succession.

Mangroves represent taxonomically diverse, salt-tolerant, woody vegetation of seed-bearing plants growing in the intertidal regions of tropical and sub-tropical regions of the world. Unlike other plant formations, mangroves constitute a complete ecosystem having many floral, faunal and microbial components occupying different niches. It is a classical example of a detritus-driven ecosystem having the highest rate of primary productivity. In the energy pyramid of the mangrove, vascular plants are the significant primary producers.

In India, mangroves are distributed all along the coastal areas, including Andaman-Nicobar and Lakshadweep islands. Mangroves occupy about 1,140 km² area along the 6,740 km coast (Bahuguna and Nayak, 2002). Along the 720 km coastline of Maharashtra state, mangroves are distributed in six coastal districts, viz., Thane, Greater Mumbai, Suburban Mumbai, Raigad, Ratnagiri and Sindhudurg occupying around 330 km² area. Mumbai, the commercial capital of India, has got around 25 km² mangrove forest and they are found mostly along creeks like Thane, Bassain, Malad, Manori and Mahim and islands like Elephanta and Butcher (Deshmukh, 1990).

Once in abundance, the mangrove flora in Mumbai is facing a serious threat of extinction because of increasing urbanization. Mumbai, which once upon a time used to be group of many islands harboring luxurious and diverse mangrove vegetation, is now a continuous landmass because of massive land reclamation activities. Besides land reclamation, water pollution, overexploitation, woodfelling are some of the other problems affecting Mumbai mangroves (Shindikar, 2002).

Life Sciences Journal, Habitat-Based Diversity Assessment, Microbial Components, Mangrove Diversity, Vegetation Analysis, Mangrove Community, Mangrove Vegetation, Geomorphic Formations, Local Fishermen Communities, Mangrove Vegetation, Mangrove Swamps.