Treeline structure and regeneration pattern in protected and non-protected areas, Indian western Himalaya

Abstract

Treeline ecotone in the Himalayan region is a relevant ecological indicator of environmental perturbations and anthropogenic disturbances. Given this, six representative sites (3 each in protected and non-protected areas) were selected for assessing forest dynamics and anthropogenic disturbances in treeline ecotone in the western Himalaya. The study reveals that treelines under protected areas show higher species richness (27) and species diversity (3.42) compared to species richness (17) and species diversity (2.22) in the non-protected areas. The average TBA of tree species was higher (36) at protected sites compared to 27 in the non-protected sites. Further, the average density of seedlings (7587) and saplings (633) was higher in protected sites than in non-protected sites (seedlings-1720 & 263-saplings). Thus, the better regeneration of dominant tree species with an expanding population structure in the protected area. This showed the efficient role of protected sites in biodiversity conservation and management. Livestock grazing and fuelwood harvesting were the key human-induced pressures in the non-protected sites. Fuelwood consumption was recorded as a maximum (5.4 kg/capita/day) for Kuti village (3800 m) in the Byans Valley, followed by Sipu (3.4) in Darma Valley and a minimum for Martoli (2.4) in Johar Valley. Anthropogenic disturbances have impacted the regeneration and recruitment of tree species in treeline ecotone in the non-protected sites. An increasing number of seedlings and saplings was observed in an open canopy of treeline ecotone, which indicates an expanding number of seedlings and saplings was observed in the open canopy treeline ecotone, which suggests the possibility of expansion of tree species towards higher elevations. Long-term ecological monitoring and observation are suggested to understand better spatial and temporal changes in treeline ecotone considering climate change and anthropogenic disturbances.