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In spite of many theoretical explanations, the plant richness pattern along the mountain elevation gradient is still debatable. Here we considered East district of Sikkim state in the Eastern Himalaya to study plant richness pattern of vascular plants along an elevation gradient of 500–3300 m at 100, 200 and 300 m elevation steps. The study evaluates species-area relationships along the elevation gradient, spread over four major forest types i.e., low (tropical to sub-tropical, up to 900 m), middle (subtropical, 750–1500 m), upper (wet temperate, 1500–2700 m) and Rhododendron-Conifer Zone (cold temperate/sub-alpine, 2700–3600 m) with 664 species from 367 genera and 131 families. Pteridium aquilinum was found to be the most diverse species occurring in all 28-elevation steps along 500–3300 m, followed by Polystichum lentum, Polygonum runcinatum and Nephrolepis cordifolia those occured in 23 elevation steps. In general, a hump shaped pattern was observed for plant richness of all life forms along the elevation gradient. The peaks became prominent, with the increase in scale of extent from 100 m (R2 = 50%) to 300 m (R2 = 78%) through 200 m (R2 = 55%) elevation steps, using 2nd order polynomial fitting. The reduction in tree height and richness was noticed beyond 2300 m allowing dominance of herbs owing to climatic constraints. Using generalized additive model, temperature could explain the maximum deviance of > 47%. Soil explained 36.4% deviance, followed by precipitation (21.6% deviance) in the plant richness. However, the ecotone effect of different forest types explained the mid-elevation peaks in plant richness more prominently than the geographic area availability. Further, inclusion of disturbance and biotic interactions may improve ecological understandings on the plant richness pattern along the elevation gradient. [ABSTRACT FROM AUTHOR]

Understanding the patterns of biodiversity is central to species conservation planning. Here we illustrate chiropteran diversity and distribution pattern of the hill ranges of the Eastern Ghats of Odisha state, India using roost survey and mist net survey techniques. The present study recorded 23 bat species including two newly recorded species for the study site i.e., Hipposideros galeritus and Megaderma spasma. The bat capture rate was the highest in the moist deciduous forest describing higher bat populations compared with the places of human habitation. Utilities of 21 climate, three physiographic and two disturbance variables and species distribution modelling could reveal that the north-eastern part was more suitable for bat distributions than the southern part of the region. The climate, physiographic and disturbance variables were crucial in their distributions, where elevation and potential evapotranspiration were highly significant. Unlike other species, Taphozous melanopogon showed negative correlation with these variables. The mean diurnal temperature and precipitation seasonality have positive influence on bat distributions, indicating their resilience to seasonal precipitation changes and day time temperature fluctuations. The negative effect of temperature seasonality on the distribution of Pteropus giganteus could attribute to its vulnerability to climate change effects. The study provides inputs for monitoring the future spatio-temporal changes, suggesting long term conservation measures. It could generate basic information on the impacts of climate change on bat distribution in the future climate change scenario. [ABSTRACT FROM AUTHOR]

Climate change enhances invasive species distribution by altering species composition in native ecosystems. Here we assessed harmony in plant invasions of two perennial exotic species of similar origin and naturalised in India, i.e., Chromolaena odorata and Tridax procumbens. Predictions made for the current condition was subsequently projected for the years 2050 and 2100 for both moderate and extreme climate change scenarios. Maximum Entropy (Maxent) was applied to assess their habitat suitability, risk area identification and shifts in range sizes. The distribution of C. odorata could mostly depend on temperature and moisture availability; and invade the biodiversity-rich regions of India viz., the Eastern Ghats, the Western Ghats, the Eastern Himalaya and the north-eastern regions. The prevalence of T. procumbens in central regions of India could demonstrate its greater dependencies on precipitation seasonality and radiation than that on temperature. These discrepancies in climatic dependencies allowed both for a harmonious distribution, i.e., inhabiting in regions not utilised by other. Both are likely to reduce their potential distribution areas in the future climate, where moisture availability is a key factor for their range expansion. The capacity to tolerate a wide range of temperature and solar radiation allowed T. procumbens to manage climate change impacts more efficiently, compared with C. odorata. The present study reveals harmony in their distributions and suggests distinct conservation protocols for each of them to control their invasion risks. [ABSTRACT FROM AUTHOR]