Pattern of structure and regeneration of forests along the disturbance gradient in and around Kedarnath Wildlife Sanctuary, India
摘要
The present study was conducted in the temperate forests between 1800 and 3500 m asl to elucidate the composition and regeneration dynamics along the disturbance gradients. Tree species richness was highest for moderately disturbed broad-leaved forests. The tree density ranged from 550 to 1420 trees ha−1, and total basal cover between 36.72 and 132.66 m2 ha−1. Rhododendron arboreum and Lyonia ovalifolia were the most widely distributed tree species in the study area. Tree diversity decreased with increasing disturbance, showing negative correlations with canopy cover (r = -0.683, P ≤ 0.01) and cut-stump density (r = -0.620, P ≤ 0.01). However, canopy cover indicated a positive correlation with sapling (r = 0.698, P ≤ 0.01) and seedling (r = 0.704, P ≤ 0.01) diversity. The seedling (11825 seedlings ha−1) and sapling (3640 saplings ha−1) were observed maximum in the least (FT7) to moderately (FT8) disturbed forests. An asymmetrical, inverse 'J' shaped distribution (positively skewed) reflected the scarcity of mature trees (individuals of higher diameter classes) in almost all forest types. The recruitment of new tree species outside their conventional habitats may result in compositional changes across many forest stands/types. The Canonical Correspondence Analysis results revealed that the five prominent disturbance indices were significant (F = 6.34, P = 0.048) in determining the pattern of tree species distribution along the axes. The total explained variance was found 69.43% for axis1 and 44.08% for axis2. Similarly, the eigenvalues were 0.2108 and 0.1212 for the corresponding axes. Canopy cover, light attenuation, and lopping intensity were the primary factors regulating the composition and regeneration of tree species in the studied forest types. The study concluded that minimizing human interventions is crucial to prevent habitat loss, and hence assisted regeneration is recommended for poor and non-regenerating tree species to maintain the composition.