HUSSAIN et al. 167 Tropical Ecology 49 (2): 167-181, 2008 ISSN 0564-3295 © International Society for Tropical Ecology www.tropecol.com Species composition and community structure of forest stands in Kumaon Himalaya, Uttarakhand, India M. SHAH HUSSAIN* #, AISHA SULTANA #, JAMAL A. KHAN & AFIFULLAH KHAN Department of Wildlife Sciences, Aligarh Muslim University, Aligarh 202 002, India Abstract: The paper describes species composition and community structure of 23 forest stands in Kumaon Himalaya (28° 43' 55" to 30 ° 30' 12" N and 78 ° 44' 30" to 80 ° 45' E), between altitudes 1500-3000 m. A total of 902 plots was sampled following plot sampling method. Density and diversity measures were calculated for different vegetation layers of each stand. TWINSPAN identified 19 tree communities and 17 ground vegetation communities. The distribution of tree species on DCA axis 1 indicated influence of altitudinal gradient while the second axis of DCA indicated canopy cover and shrub diversity. The first component of PCA represented open to close canopy forest, while the second reflected increase in shrub density and diversity. Quercus floribunda-Rhododendron arboreum group had maximum tree density and Abies pindrow-Betula utilis the minimum. Myrsine africana was the dominant shrub species. Maximum tree species diversity and richness were recorded for Daphiadhura site whereas the Vinaiyak site expressed maximum shrub diversity. Pinus wallichiana , Betula utilis , Tsuga demosa, etc. were found to be rare tree species. Resumen: El artículo describe la composición de especies y la estructura de la comunidad de 23 rodales de bosque en Kumaon Himalaya (28° 43' 55" a 30 ° 30' 12" N, y 78 ° 44' 30" a 80 ° 45' E), ubicadas entre las altitudes de 500-3000 m. En total se muestrearon 902 parcelas, utilizando el método de muestreo con área. Se calcularon medidas de densidad y diversidad para las diferentes capas de vegetación de cada rodal. El análisis TWINSPAN identificó 19 comunidades arbóreas y 17 comunidades del suelo del bosque. La distribución de las especies arbóreas en el eje 1 del DCA indicó una influencia del gradiente altitudinal, mientras que el segundo eje del DCA indicó la cobertura del dosel y la diversidad de arbustos. El primer componente de un PCA representó bosque de dosel abierto a cerrado, mientras que el segundo reflejó el incremento en la densidad de arbustos y su diversidad. El grupo Quercus floribunda-Rhododendron arboreum tuvo la máxima densidad de árboles, y el de Abies pindrow-Betula utilis , la mínima. Myrsine africana fue la especie de arbusto dominante. Los valores máximos de diversidad y riqueza de especies arbóreas fueron registrados en el sitio Daphiadhura, mientras que en el sitio Vinaiyak se expresó la máxima diversidad de arbustos. Se encontró que Pinus wallichiana , Betula utilis y Tsuga demosa , entre otras, fueron especies raras. Resumo: O artigo descreve a composição e a estrutura de comunidade de 23 parcelas florestais em Kumaon Himalaia (28° 43' 55" to 30 ° 30' 12" N e 78 ° 44' 30" to 80 ° 45' E), entre as altitudes de 1500-3000 m. Um total de 902 parcelas foram amostradas seguindo o método de amostragem de quadrados. As medidas da densidade e diversidade foram calculadas para diferentes andares de vegetação em cada parcela. A análise TWINSPAN identificou 19 * Corresponding Author ; e-mail: [email protected] , [email protected] #Present Address: Centre for Environmental Management of Degraded Ecosystems, School of Environmental Studies, University of Delhi, Delhi 110007, India 168 FOREST STRUCTURE IN KUMAON HIMALAYA comunidades arbóreas e 17 comunidades de vegetação rasteira. A distribuição das espécies arbóreas no eixo DCA indicam a covertura pelo copado e a diversidade dos arbustos. A primeira componente do ACP representou florestas com copado aberto a fechado, enquanto a segunda reflectiu o aumento na densidade e diversidade dos arbustos. O grupo Quercus floribunda- Rhododendron arboreum apresentou a densidade arbórea máxima e o Abies pindrow-Betula utilis o mínimo. A Myrsine africana foi a espécie arbustiva dominante. A diversidade arbórea máxima e riqueza foi registada para a estação Daphiadhura enquanto a estação Vinaiyak expressou a diversidade arbustiva máxima. Encontrou-se que a Pinus wallichiana , Betula utilis , Tsuga demosa , etc. eram espécies arbóreas raras. Key words: Forest conservation, Himalaya, Himalayan forests, India, ordination, rare species, vegetation community. Introduction Materials and methods Himalaya, the youngest mountain system of Study area the world, constitutes an important link between The study was conducted in 23 forest stands the vegetation of the southern peninsular India including Binsar Wildlife Sanctuary (BWS) and on the one hand, the eastern Malaysian, the Askot Wildlife Sanctuary (AWS), in five districts; north-eastern Sino-Japanese and the northern Almora, Bageshwer, Champawat, Naini Tal and Tibetan areas on the other (Puri et al . 1983). Pithoragarh of Kumaon Himalaya (28° 43' 55" to Several studies have described the vegetation of 30 ° 30' 12" N latitude and 78° 44' 30" to 80 ° 45' E Kumaon (Dhar et al. 1997; Rikhari et al. 1989a; longitude) covering an area of 21,032 km² in the Singh et al. 1984; Singh & Singh 1984; Singh & Uttarakhand state of India (Fig. 1, Table 1). Singh 1987; Singh et al. 1987; Tiwari & Singh Kumaon Himalaya is altitudinally divisible into 1985; Upreti et al. 1985) and Garhwal Himalaya subtropical (300 to 1500 m), temperate (1500 to (Anthwal et al . 2006; Kumar & Bhatt 2006; 3500 m) and alpine (>3500 m) zones (Saxena et al. Nautiyal et al. 2004). Some of the studies 1985). Annual rainfall peaks at about 1200 m described altitudinal variation in vegetation altitude (4100 mm) and gradually declines to 670 (Adhikari et al. 1992; Saxena et al . 1985) and mm at 2700 m (Saxena et al. 1985). reported that vegetation types differ with change in altitude. However, Puri et al. (1983) observed Sampling procedures that geology and soils may exercise a far greater influence on the distribution of vegetation types Overall 902 sampling plots were laid in the 23 than the altitude or climate. forest stands (details in Table 1). Vegetation was Some pioneering contributions on sampled along existing forest trails which passed phytosociology (Ralhan et al. 1982; Saxena & through all the major habitat types to permit Singh 1982) and population structure (Saxena et sampling of different habitats in equal proportion al . 1985; Singh et al . 1987) of certain central at each site. In each stand, sampling plots were 50 Himalayan forest types have already been m apart, and each was laid at a distance of 10 m reported. The main objectives of this paper are: (i) from the edge of the trail on either side to avoid to describe structural attributes (density, species sampling of the relatively disturbed vegetation. diversity and richness) of tree, shrub and ground Number of plots sampled in different stands is layers; (ii) to identify predominating communities given in Table 1. of trees and ground vegetation, and plant species At each sampling plot, a 10 m radius circular of special concern, and to further identify the plot (Dombois & Ellenberg 1974) was established. localities having rare plant communities needing Trees > 4 m height were considered mature trees. protection. Species and their individuals were recorded for the HUSSAIN et al. 169 Fig 1. Location of 23 surveyed forest stands in Kumaon Himalaya. estimation of density, species diversity and species distance from the sampling point in four different richness. Shrub layer was quantified in 3 m radius directions using gridded mirror of 25.4 x 25.4 cm circular plots whereas ground vegetation (herbs (10 x 10 inch) dimension, divided into 25 equal and grasses) was estimated in 0.5 m x 0.5 m grids. Grids covered with > 50% foliage were quadrats at four places within the 10 m radius counted and expressed in terms of percent tree sampling plot. Tree cover was measured at 5 m cover (Dombois & Ellenberg 1974). 170 FOREST STRUCTURE IN KUMAON HIMALAYA Density and diversity estimates ordination of tree species as well as sites (forest stands) through Detrended Correspondence Density of trees, shrubs and ground vegetation Analysis (DCA) in computer program DECORANA was calculated following Greig - Smith (1983). The (Hill 1979 b). The vegetation attributes (density, diversity values for each layer (tree, shrub and diversity and richness) of the 23 sites along with ground vegetation) were calculated using Shannon altitude, number of stumps, lopped trees and cattle - Wiener’s diversity index following Magurran dung were subjected to Principal Component (1988). The species richness was calculated using Analysis (PCA). Margelef’s species richness index (Magurran Stepwise multiple regression was used to 1988). One-way ANOVA (Zar 1984) was used to obtain correlation between the DCA axes, and detect significant differences in density, diversity measured environmental and vegetation and richness for the vegetation layers in all the attributes. All data matrices were standardized surveyed forest stands. following Zar (1984) to achieve normality and reduce heteroscadesticity. Classification and ordination of species and sites Rarity index The vegetation was classified on the basis of A rarity index was generated to identify rare tree species and dominant ground vegetation tree species of Kumaon. For this purpose two (shrub and herb species) using TWINSPAN (Two- parameters were taken into account- way indicator species