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Restoration of camptothecine production in attenuated endophytic fungus on re-inoculation into host plant and treatment with DNA methyltransferase inhibitor
No full textFungal endophytes inhabit living tissues of plants without any apparent symptoms and in many cases are known to produce secondary metabolites similar to those produced by their respective host plants. However on sub-culture, the endophytic fungi gradually attenuate their ability to produce the metabolites. Attenuation has been a major constraint in realizing the potential of endophytic fungi as an alternative source of plant secondary metabolites. In this study, we report attempts to restore camptothecine (CPT) production in attenuated endophytic fungi isolated from CPT producing plants, Nothapodytes nimmoniana and Miquelia dentata when they are passed through their host plant or plants that produce CPT and when treated with a DNA methyl transferase inhibitor. Attenuated endophytic fungi that traversed through their host tissue or plants capable of synthesizing CPT, produced significantly higher CPT compared to the attenuated fungi. Attenuated fungus cultured in the presence of 5-azacytidine, a DNA methyltransferase inhibitor, had an enhanced CPT content compared to untreated attenuated fungus. These results indicate that the attenuation of CPT production in endophytic fungi could in principle be reversed by eliciting some signals from plant tissue, most likely that which prevents the methylation or silencing of the genes responsible for CPT biosynthesis
The Influence of Environmental Factors and Landcover Change on the Distribution and Metacommunity Structure of Upper Montane (Shola) Forests in the Western Ghats
Get PDFTropical montane cloud forests are unique habitats with great ecological and hydrological
significance. In the Western Ghats, these upper montane forests (also known as sholas) and
associated grassland habitats form approximately 1% of the land area but harbour
disproportionately high numbers of endemic taxa. Despite their great conservation significance,
little is known about how patterns of tree and shrub species composition vary across space, how
environmental factors such as soil, climate and topography affect tree and shrub community
composition, and how widespread conversion of surrounding grasslands to tea and exotic tree
plantations has affected shola forest communities. The naturally fragmented nature of shola communities, which display patchiness at hierarchically
nested scales, also makes them an ideal system in which to study metacommunity structure as
species distributions, interactions and ecological processes, within and across fragments are
likely to have equilibrated over many hundreds of generations (for trees). Hence the central
underlying assumption of the species sorting perspective of the metacommunity framework, (i.e.
that local community dynamics are at equilibrium) is more likely to be met in such a system.
Further, recent conversion of the natural grassland matrix to exotic tree plantations and tea
estates, is likely to have disrupted this equilibrium in complex and unpredictable ways, which
can provide greater insights into mechanisms driving metacommunities dynamics in general and
effects of landscape matrix conversion on plant communities in particular. In this thesis I attempt to understand the patterns of distribution and plant community
composition of shola forests and their drivers at different spatial scales. I investigate the
topographic and bioclimatic determinants of vegetation pattern within shola-grassland mosaics
across their distribution in the central and southern Western Ghats. I then focus on studying the
distribution and metacommunity patterns of shola tree and shrub species at the landscape scale in
the southern and western Upper Nilgiris Plateau. I identify important environmental gradients
structuring tree and shrub metacommunities, and determine the extent to which the latter are
influenced by abiotic factors such as climate, topography and soil versus biotic factors such as
dispersal. I also examine effects of grassland conversion to tea and exotic tree plantations on the
structure, composition and regeneration of shola forest fragments. In order to fulfil these objectives, I use various analytic approaches including conditional
inference classification trees, generalized linear models with an information theoretic framework,
spatial eigenvectors and variation partitioning. I also develop a novel approach to modelling
spatial connectivity created by dispersal processes in topographically heterogeneous terrain using
a combination of spatial eigenvectors derived from a Circuit Theory approach. I find that both vegetation pattern within shola-grassland mosaics in general, and the shola tree
and shrub metacommunity in particular, are strongly structured by the elevation gradient. In
particular, above approximately 2000m elevation, there appear to be shifts in both the
distribution of forest and grassland within these mosaics, as well as large changes in community
composition within shola fragments. The shola metacommunity in the Upper Nilgiris primarily
exhibits a Clemenstian pattern of species distribution along an elevation gradient with high
turnover and significant clumping of range boundaries. Spatially structured environmental
variability, accounts for much of the explained variation in shola tree and shrub abundances,
while dispersal limitation accounts for about 10% of explained variation. Approximately half of
the variation in tree and shrub communities remains unexplained by the environmental, historical
and spatial predictors considered. Finally, sholas located within a landscape matrix of grassland
differ significantly in terms of structure, composition as well as regeneration levels from those
located within an altered landscape matrix of tea plantations and wattle (Acacia mearnsii),
indicating that landscape matrix conversion has affected the structure and dynamics of vegetation
in sholas. I present a synthesis of the main results and conclusions with a discussion of potential climate
change impacts on shola forests and further research priorities. The specific conservation and
management implications emerging from this study are also highlighted
Perceptions of priority issues in the conservation of biodiversity and ecosystems in India
No full textWe report on the results of a country-wide survey of people’s perceptions of issues relating to the conservation of biodiversity and ecosystems in India. Our survey, mainly conducted online, yielded 572 respondents, mostly among educated, urban and sub-urban citizens interested in ecological and environmental issues. 3160 ‘‘raw’’ questions generated by the survey were iteratively processed by a group of ecologists, environmental and conservation scientists to produce the primary result of this study: a summarized list of 152 priority questions for the conservation of India’s biodiversity and ecosystems, which range across 17 broad thematic classes. Of these, three thematic classes—‘‘Policy and Governance’’, ‘‘Biodiversity and Endangered Species’’ and ‘‘Protection and Conservation’’—accounted for the largest number of questions. A comparative analysis of the results of this study with those from similar studies in other regions brought out interesting regional differences in the thematic classes of questions that were emphasized and suggest that local context plays a large role in determining emergent themes. We believe that the ready list of priority issues generated by this study can be a useful guiding framework for conservation practitioners, researchers, citizens, policy makers and funders to focus their resources and efforts in India’s conservation research, action and funding landscape
A New Species of Pethia from the Western Ghats, India (Teleostei: Cyprinidae)
No full textPethia striata, new species, is described from the Tunga River in Kudremukh National Park, in the central part of the Western Ghats, Karnataka State, India. The new species is distinguished from its congeners by the combination of the following characters: absence of barbels; stiff and serrated last unbranched dorsal-fin ray; complete lateral line with 20–21 pored scales and a relatively small humeral spot one scale below the fourth lateral-line scale; a large black blotch covering lateral-line scales 17–19. In addition, the outer edges of body scales are dark, producing a striped pattern
along the sides of the body. Pethia striata, new species, is presently known only from headwater-streams of the Tunga River basin
How Do Fruit Bat Seed Shadows Benefit Agroforestry? Insights from Local Perceptions in Kerala, India
No full textOld-world fruit bats are known to provide significant benefits to tropical agroforestry through seed dispersal services. However, the social pathways through which local people perceive and actually utilize these benefits are not well understood. Through interview surveys with plantation owners and farmers in the Western Ghats of Kerala (India), we documented local perceptions and knowledge about the socio-ecological importance of fruit bat seed dispersal shadows. Respondents’ perceptions were highly positive, with greater benefits reported from seed dispersal, than costs from fruit damage by bats. Interestingly, seed aggregation of commercial fruit crops (cashew, areca) by fruit bats was perceived to reduce agricultural labour costs in plantations. Our study demonstrates that local perceptions can offer valuable insights toward understanding the contribution of bat-generated ecosystem services for tropical agroforestry systems, and in turn may facilitate effective fruit bat conservation
Acoustic identification of Otomops wroughtoni and other free-tailed bat species (Chiroptera: Molossidae) from India
No full textThe Wroughton’s free-tailed bat Otomops wroughtoni (Chiroptera: Molossidae) is a globally rare and data-deficient species. This species has been recorded only from four locations, in India and Cambodia, with the type locality in the Barapede caves, India. In this paper, we present an analysis of echolocation and social calls of O. wroughtoni from the Barapede caves. Echolocation calls
of free-flying O. wroughtoni were narrowband and shallow frequency-modulated (shallow-FM), with peak frequency ranging between 14–17 kHz. Social call sequences of roosting O. wroughtoni showed five distinct signatures. Multivariate analyses of echolocation calls of O. wroughtoni and the other three molossid species found in India (Tadarida teniotis, T. aegyptiaca, Chaerephon plicatus), showed strong support for acoustic differentiation of these species. Our study will help identify probable occurrence of O. wroughtoni and the other species in unsurveyed areas through field acoustic surveys. It also proposes hypotheses about the ecology and foraging behaviour of O. wroughtoni that could be tested through further studies
The ‘empty forests’ of the northern Eastern Ghats
Get PDF‘The bow stretched and in a moment the blunt arrow whizzed vertically up into the trees, a moment later the man reluctantly picked the arrow, looked up and walked away. The bird flock in the canopy was momentarily silent and then flew way. The hunt was not successful and the birds escaped. The hunter then turned a trapper as he went about setting several small and big traps along the
fields and forests. He came back the next day to check. It was the same story either the animals outwitted the traps or there
were none to get trapped.
Effect of Climate Change on Invasion Risk of Giant African Snail (Achatina fulica Férussac, 1821: Achatinidae) in India
Get PDFThe Giant African Snail (Achatina fulica) is considered to be one the world’s 100 worst invasive alien species. The snail has an impact on native biodiversity, and on agricultural and horticultural crops. In India, it is known to feed on more than fifty species of native plants
and agricultural crops and also outcompetes the native snails. It was introduced into India in 1847 and since then it has spread all across the country. In this paper, we use ecological niche modeling (ENM) to assess the distribution pattern of Giant African Snail (GAS) under
different climate change scenarios. The niche modeling results indicate that under the current climate scenario, Eastern India, peninsular India and the Andaman and Nicobar Islands are at high risk of invasion. The three different future climate scenarios show that there is no
significant change in the geographical distribution of invasion prone areas. However, certain currently invaded areas will be more prone to invasion in the future. These regions include parts of Bihar, Southern Karnataka, parts of Gujarat and Assam. The Andaman and Nicobar and Lakshadweep Islands are highly vulnerable to invasion under changed climate. The Central Indian region is at low risk due to high temperature and low rainfall. An understanding of the invasion pattern can help in better management of this invasive species and also in formulating policies for its control
Thinking about Urban Resilience: The Case of Water Scarcity and Wastewater Reuse in Bengaluru
Get PDFWITH ORIGINS in the ecological sciences, the concept of resilience gained currency in the context of climate change. The ‘classical’ ecological notions of resilience emphasize recovery to a prior state in the aftermath of stress or shock. The broader social-ecological notion of resilience focuses on learning, innovation, adaptive capacity and transformation (Folke, 2006: 259). The literature on urban resilience (Leichenko, 2011; Romero Lankao and Qin, 2011: 145-6) discusses systems bouncing back to ‘equilibrium’ in the aftermath of shocks, such as natural disasters (drawing from the classical literature), as well as the adaptive capacities of systems to long-term stressors or shifts such as climate change
Why is the Arkavathy River drying? A multiple-hypothesis approach in a data-scarce region
Get PDFWater planning decisions are only as good as our ability to explain historical trends and make reasonable predictions of future water availability. But predicting water availability can be a challenge in rapidly growing regions, where human modifications of land and waterscapes are changing the hydrologic system. Yet, many regions of the world lack the long-term hydrologic monitoring records needed to understand past changes and predict future trends. We investigated this “predictions under change” problem in the data-scarce Thippagondanahalli (TG Halli) catchment of the Arkavathy sub-basin in southern India. Inflows into TG Halli reservoir have declined sharply since the 1970s. The causes of the drying are poorly understood, resulting in
misdirected or counter-productive management responses.
Five plausible hypotheses that could explain the decline
were tested using data from field surveys and secondary
sources: (1) changes in rainfall amount, seasonality and intensity; (2) increases in temperature; (3) groundwater extraction; (4) expansion of eucalyptus plantations; and (5) fragmentation of the river channel. Our results suggest that groundwater pumping, expansion of eucalyptus plantations and, to a lesser extent, channel fragmentation are much more likely to have caused the decline in surface flows in the TG Halli catchment than changing climate