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When the habitat occupied by a specialist species is patchily distributed, limited gene flow between the fragmented populations may allow population differentiation and eventual speciation. 'Sky islands'-montane habitats that form terrestrial islands-have been shown to promote diversification in many taxa through this mechanism. We investigate floral variation in Impatiens lawii, a plant specialized on laterite rich rocky plateaus that form sky islands in the northern Western Ghats mountains of India. We focus on three plateaus separated from each other by ca. 7 to 17 km, and show that floral traits have diverged strongly between these populations. In contrast, floral traits have not diverged in the congeneric I. oppositifolia, which co-occurs with I. lawii in the plateaus, but is a habitat generalist that is also found in the intervening valleys. We conducted common garden experiments to test whether the differences in I. lawii are due to genetic differentiation or phenotypic plasticity. There were strong differences in floral morphology between experimental plants sourced from the three populations, and the relative divergences between population pairs mirrored that seen in the wild, indicating that the populations are genetically differentiated. Common garden experiments confirmed that there was no differentiation in I. oppositifolia. Field floral visitation surveys indicated that the observed differences in floral traits have consequences for I. lawii populations, by reducing the number of visitors and changing the relative abundance of different floral visitor groups. Our results highlight the role of habitat specialization in diversification, and corroborates the importance of sky islands as centres of diversification., Competing Interests: The authors have declared that no competing interests exist.

Western Ghats of India is rich in floristic diversity and endemism. However, being highly threatened with anthropogenic stressors, with only 6.8% of its original vegetation still extant, along with Sri Lanka it is considered as a biodiversity hotspot. It has been suggested that sacred groves in Western Ghats could act as refuge for the relic flora of this region. Sacred groves are the forest patches conserved since centuries due to religious beliefs and are the remnants of the climax vegetation containing endemic and endangered species of plants and animals. However, due to severe deforestation and urbanization, sacred groves are facing serious problems. In present investigation, sacred groves from Pune district, Maharashtra, were studied for their ecological role and their response to physical as well as degradation related parameters. Two hundred ninety six species of plants belonging to 100 families including 45 endemic species were recorded from these groves. Similarity between sacred groves is independent of distances accounting for only 30% for the groves as close as 2.5 km from each other. Physical parameters such as altitude and presence of streams are positively correlated with number of endemic species. Increase in the degradation including cutting, lopping; construction activities have affected the species richness across different sacred groves. Our results show that each sacred grove is unique in terms of biodiversity it contains and demands dedicated conservation efforts. [ABSTRACT FROM AUTHOR]

Catchment landscape degradation and habitat modifications of freshwater ecosystems are a primary cause of biodiversity loss in riverine ecosystems all over the world. Many elements of the flora and fauna of freshwater ecosystems are sensitive to the changes in catchment land use and habitat modification. These sensitive taxa are also reliable indicators of freshwater ecosystem health. In the current study we investigate the seasonal and habitat distribution of Odonata (Insecta) across riparian land use types in Mula and Mutha river basins, northern Western Ghats, Maharashtra. There was a difference in the species composition across land use types and across seasons with highest diversity and abundance during the post monsoon period. The highest Odonata diversity was observed in urban areas followed by forest and agriculture fields. There was a loss of 31% of the odonate fauna in the study area over 50 years which could be due to rapid industrialization and urbanization of the region and consequent degradation of freshwater ecosystems. The significance of catchment land use on Odonata diversity and its value in landscape monitoring is discussed. [ABSTRACT FROM AUTHOR]