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Elevational gradients impact organisms in diverse ways because of lower temperatures and oxygen levels at higher elevations. Birds adapt to these constraints through changes in body size, plumage, metabolism, and behaviors such as elevational migration. But whether species show variation across multiple axes of adaptations along a single elevational gradient is not well demonstrated in the literature. The broad elevational distribution of the House Sparrow Passer domesticus in the Himalayas provides a rare insight into whether morphological and plumage modifications can simultaneously arise within a species across its elevational distribution. Drawing insights from eco-physiological patterns, we hypothesized that sparrows at higher elevations would exhibit larger body sizes (Bergmann’s rule), shorter extremities (Allen’s rule), and a more insulative feather structure. We sampled sparrows at 13 sites (n = 169) from 300 m to 3500 m along an elevational gradient in the western Himalayas and found that sparrows at higher elevations were significantly larger following Bergmann’s rule, and had more downy dorsal feathers likely giving higher-elevation sparrows thermal advantages at low temperatures. We show that House Sparrows may show convergent modifications in response to temperature clines whether they are elevational or latitudinal.

Multiple drivers maintain unique species assemblages at multiple biogeographic scales. Here, the authors show that the freezing line is a key barrier generating evolutionary differences in temperate and tropical bird communities across a steep elevational gradient in the Himalaya.

Recent declines in large herbivores have led to significant conservation efforts globally. However, the niche-specific megaherbivores residing outside protected areas face more imminent extinction threats. Swamp deer, the obligate grassland-dwelling endemic cervid is the most extinction-prone megaherbivore in the Indian subcontinent. Limited information on distribution and habitat status pose significant conservation and management challenges for the remaining fragmented populations in north, north-east and central India. To this end, we combined exhaustive field surveys and Maximum Entropy (MaxEnt) modeling to generate the most detailed distribution map for the northern swamp deer subspecies. We used primary data from more than 6000 km2 field surveys and eight ecologically relevant covariates for model predictions. Grassland cover, annual mean temperature and distance from water were the major factors that predicted the species distribution. Models predicted swamp deer distribution in only ~3% of the entire landscape, covering both protected (~1.4%) as well as non-protected (~1.6%) areas. Our validation surveys in some of these predicted areas confirmed swamp deer presence and indicated ~85% model accuracy. Finally, we identified four ‘‘Priority Conservation Areas’’ still retaining adequate grassland habitat and species presence that require immediate attention to ensure landscape-level population connectivity. These results highlight the importance of the marginalized grassland ecosystems of northern India that still retain high biodiversity. We suggest a swamp deer-centric conservation approach to protect these human-dominated habitats and emphasize in generating such information for other endemic, habitat-specialist species across the globe.

The Okhla Bird Sanctuary (OBS), a man-modified floodplain wetland having high human impact, is located in an urbanized landscape. Its location in the Central Asian Flyway of migratory birds makes it an ideal transit and wintering ground for birds. This paper describes the vegetation composition and significance of the Sanctuary as a bird habitat. A floristic survey was carried out from winter 2009 to spring 2010 while preparing a management plan for OBS. 192 species of plants belonging to 46 families were recorded from the area. Thirteen species of weeds were observed covering 70% of the sampled area in peak summer. Among trees, highest density was found for two exotic species viz., Leucaena leucocephala and Prosopis juliflora. The aquatic system is facing threat from proliferation of Eichhornia cressipes and Typha angustifolia. Strategic eradication of invasive and plantation of native species in the sanctuary are needed for better management.