ASSESSMENT OF VEGETATION AND PRIORITIZATION OF COMMUNITIES FOR CONSERVATION IN LATAKHARAK ALPINE MEADOWS OF NANDA DEVI BIOSPHERE RESERVE, WEST HIMALAYA, INDIA

S. C. Arya 1 and S. S. Samant 2 . 1. G.B. Pant National Institute of Himalayan Environment and Sustainable Development North-East Unit, Vivek Vihar, Itanagar791 113, Arunachal Pradesh. 2. G.B. Pant National Institute of Himalayan Environment and Sustainable Development Himachal Unit, MohalKullu-175 126, Himachal Pradesh, India. ...................................................................................................................... Manuscript Info Abstract ......................... ........................................................................ Manuscript History

The Study Area:-Nanda Devi Biosphere Reserve (NDBR) (3005'-3102'N to 7912'-8019'E) covering a total of 6,407.03 km 2 (Core zone 712.12 km 2 ; Buffer zone 5,148.57 km 2 and Transition zone 546.34 km 2 ), is situated in the northern part of west Himalaya (Fig. 1) and is among the World Heritage Sites. The reserve includes parts of Bageshwar and Pithoragarh districts in Kumaun region, and Chamoli district in Garhwal region. The buffer and transition zones are inhabited by over 100 villages. Most of the inhabitants belong to two main ethnic groups namely Indo-Mongoloid (Bhotia) and Indo-Aryans. They have been using plants as medicine, edible/food, fodder, fuel, timber, agricultural tools and various other purposes (Samant, 1996b;Joshi et al., 1999Joshi et al., , 2001. Present study has been conducted in the Latakharak alpine meadows, located in the Chamoli district, a part of NDBR.

Methods:-Identification and Selection of Sites and Habitats:-
Sites have been selected in each and every accessible aspect along transacts between 3000-4270m, amsl. In each site, habitat type, altitude, aspect, slope, boulder percentage and dominant species were noted. Habitats were identified on the basis of physical characters (Samant et al., 1998a). The sites having >50% boulders of the ground cover have been identified as bouldery habitat.

Survey, Sampling, Identification and Analysis of Data:-
The field surveys and samplings were carried out during 1998-2000 within selected sites along transacts. For the sampling of vegetation 20x20m plot was marked in each site and 20 quadrats (1x1m) in each plot were laid by stratified method. Sampling was done in the peak season i.e., August and September. For data collection and analysis standard ecological methods (Grieg-Smith, 1957; Kersaw, 1973;Muller-Dombois & Ellenberge, 1974;Dhar et al., 1997) were followed. Shrubs present in each site were noted to update the species composition. From each site, samples of each species were collected and identified in the Institute with the help of florulas and research papers (Naithani, 1984(Naithani, & 1985Polunin & Stainton, 1984;Samant 1993Samant , 1999Pangtey et al., 1993;Hajra & Jain, 1981;and Hajra & Balodi, 1995). Abundance data of different sites were pooled to get community average in terms of density.
Community Delineation, Identification of Nativity, Endemism, Human Dependence and Rarity:-Communities have been delineated based on the 50% contribution of the total relative density of the species. Species of each community have been analyzed for nativity following (Anonymous, 1883(Anonymous, -1970Samant, 1999 andSamant et al., 2000), endemism following (Dhar & Samant, 1993;Samant et al., 1998a&b, 2000, human dependence following (Samant et al. 1996a, Joshi et al., 1999, rarity following (Samant et al., 1996b(Samant et al., , 1998b     Alpine plants are distributed over different microhabitats and altitude with distinct ecological requirements (Rawat & Uniyal, 1993). In the study area, the distribution of communities and species changes in response to habitats. The tussuck forming grasses and cushion and spreading forbs covers the maximum part of the alpine meadows. Considering all the sites together, most species showed regular distribution pattern both, among sites and communities in all the areas.
The total density range among communities (26.95-1767.20 Ind m -2 ) was comparatively higher. Most of these high density were dominated by grasses, sedges, cushion, and spreading forbs indicating the proliferation of these communities in the area. The low density of Polygonum polystachyum, Danthonia cachemyriana-Polygonum affine mixed, Danthonia cachemyriana-Picrorhiza kurrooa mixed, Fragaria nubicola-Galium acutum-Viola biflora-Cardamine impatiens mixed communities may be due to high biotic pressures. Some of these communities were found in camping sites and dominated by weeds i.e., Polygonum polystachyum, Rumex nepalensis etc. These are the characteristic species of the camping sites where the organic matter was found accumulated due to the excretory wastes of the animals. Such species do not allow other species to grow. Among the habitats, camping sites, shrubberies and forest edges showed the lowest densities.
A significant negative correlation had been found between altitude and species richness (r=0.387 p<0.01 n=32) and altitude and density (r=-0.465, p<0.01 n=32) in Latakharak alpine meadows indicating that with the increasing altitude the species richness and density decreased. (Fig. 3 a-b). The occurrence of maximum number of species in Carex stracheyi and Danthonia cachemyriana-Carex stracheyi mixed, community may be attributed due to their wide range of distribution and habitat preference. Similarly, the occurrence of minimum number of species in Polygonum polystachyum and Danthonia cachemyriana-Polygonum affine mixed communities may be due to their narrow range of distribution and restricted habitats.
The Polygonum polystachyum community was represented by camping site, a habitat which have been developed due to the camping by sheep grazers and also by trampling of sheep's and goats (Ram & Singh, 1994 Due to relatively harsh climatic and topographic conditions of the alpine meadows the non-native species could not easily adapted, therefore the existence of no-native species is comparatively low in this region. Further, due to the remoteness, inaccessibility and severe climatic conditions the anthropogenic pressure is low compared to the subtropical and temperate zones of IHR. This has led to the high diversity of native and endemic species. A positive correlation had been found between species richness and native species among the communities (0.967, p<0.01 n=32) (Fig. 4). A significant positive relationship had been found between the number of useful species and number of rare species Latakharak (0.486, p<0.01 n=32), (Fig. 5) indicating that the use of the species was directly proportional to the rarity of the species.
Overall, 10 communities have been identified from the Latakharak alpine meadows of NDBR, which are comparatively higher than the communities identified from Valley of Flowers (Kala et al., 1998), Baideni Negi et al., 1992) and Panwalikantha, alpine meadows (Raizada et al., 1998). In all the alpine meadows, species richness, diversity, nativity, endemism, rarity, and use values varied from community to community. The richness of useful species in these communities indicates high anthropogenic pressure. If indiscriminate exploitation of the useful species from these communities continues, there is possibility of extinction of these species from their natural habitats leading to habitat alterations and ecosystem imbalance. Therefore, there is an urgent need to pay adequate attention for the conservation of these communities supporting ecologically and economically important species.

Conclusions:-
The present study conducted in Latakharak alpine meadows of NDBR provides data base on compositional and structural, distribution pattern of species, communities, native, endemic and rare-endangered species within different communities. The study provides a comprehensive information on human dependence on plant resources, indigenous uses, rare-endangered species, and prioritization of communities for conservation. Occurrence of 10 alpine communities, mostly representative ones and 213 species in the study area suggested its importance from the point view of conservation.
The present study indicated that species richness and density decreased with the increasing altitude. Decreasing trend of the species with the increasing altitude has been also reported in the IHR , Samant et al., 1998a, 1998b. Habitats play a significant role in the distribution pattern and growth of the plant species. Therefore, habitat wise assessment of the alpine vegetation has been carried out for the first time in the IHR. The conservation of habitats is most important for the conservation of species. If habitats are conserved, the species present will be conserved automatically.