Multifunctional high elevation agropastoral ecosystem of Eastern Himalaya complements primary forest in bird conservation

The ever-increasing demand for agricultural products due to global human explosion has resulted into deforestation and forest fragmentation leading to biodiversity loss. These paradigms have urged to identify and adopt agroforestry practices that uphold and restore biodiversity. The high elevation traditional agropastoral system prevalent in the Himalaya is one among such practices, but biodiversity wealth and ecosystem functioning of this system are not understood properly. Here, we have undertaken a study to understand the potentiality of multifunctional agropastoral mosaics located in Sikkim, Eastern Himalaya, India, in retention and conservation of temperate avifauna. We used point count method along set transects spread across five study sites spanning elevation range of 2300–3700 m to sample birds. We observed 88 bird species during the study among which 56 species including four Eurasian high montane biome species and seven Sino-Himalayan temperate forest biome species were observed in agropastoral system. Similarly, the community composition between the agropastoral system and nearby forest ecosystem (taken as control sites) differed significantly between the systems indicating the high conservation significance of agropastoral landscape mosaics for high elevation birds. Species richness and density of birds grouped into different functional categories were equivalent (or even higher in agropastoral) in both systems across the seasons. We found that these birds provide potential ecosystem services such as pest control, seed dispersal, nutrient decomposition, waste disposal, and pollination. Our results suggest that the agropastoral mosaics reflecting high habitat heterogeneity complement natural forest in retention and conservation of high elevation birds in the Himalaya. Hence, appropriate conservation measures must be undertaken to safeguard this unique multifunctional ecosystem and its avifaunal diversity.