Studies on biomass changes and nutrient lock-up efficiency in a Kashmir Himalayan wetland ecosystem, India

M. A. Khan¹ and Manzoor A. Shah²

¹Division of Environmental Sciences, S. K. University of Agricultural Sciences and Technology of Kashmir, G. P. O. Box 726, Srinagar-190001, Kashmir, India.

²Department of Botany, University of Kashmir, Srinagar, J&K, India- 190006.

*Corresponding author. E-mail: mashah75@yahoo.com.

Accepted 27 July, 2010

 Abstract

Wetlands are landscape sinks which accumulate and sequester a wide range of nutrients, heavy metals and pesticides. Whilst some studies hitherto have addressed the phyto-sociology and sequestering potential of wetland plants in isolation, we attempted to integrate the two aspects in a Kashmir Himalayan Ramsar site (Hokersar wetland), India. The results of studies (November, 2000 – October, 2001) on the seasonal biomass fluctuations and nutrient accumulation of aquatic plant communities in Hokersar wetland ecosystem are presented. Phytosociological attributes show emergents dominated by Sparganium erectum and Typha angustata, colonizing mainly the littorals. Nymphoides peltata, a dominant rooted floating plant species, is of frequent occurrence in relatively shallow and open waters. Ceratophyllum-Myriophyllum association dominates the submersed forms whilst the free-floating Lemna-Salvinia complex grows luxuriantly in side-channels. The plant biomass levels on areal basis (m^-2) fluctuated from 35 - 1100 g and the mineral concentration varied between 1.318 - 15.86 g (N), 0.052 - 0.597 (P) and 1.83 - 18.33 (K). Annual computations for nutrient lock-up potential gave values of 0.77 × 10⁶ g (N), 0.02 ×10¹ g (P) and 0.89 × 10⁶ g (K). Positive correlation was observed between aquatic plant biomass and nutrient lock-up efficiency. The results of the present study have implications for efficient eco-restoration of the wetland ecosystem through scientific management of macrophytic vegetation.

Key words: Kashmir Himalaya, aquatic plants, phytosociology, biomass, nutrient dynamics, lock-up efficiency, wetland ecosystem.