Time filter

Source Type

Bonell M.,University of Dundee | Purandara B.K.,National Institute of Hydrology | Venkatesh B.,National Institute of Hydrology | Krishnaswamy J.,Suri Sehgal Center for Biodiversity and Conservation | And 3 more authors.
Journal of Hydrology | Year: 2010

There is comparatively limited information in the humid tropics on the surface and sub-surface permeability of: (i) forests which have been impacted by multi-decades of human occupancy and (ii) forestation of land in various states of degradation. Even less is known about the dominant stormflow pathways for these respective scenarios. We sampled field saturated hydraulic conductivity, K* at 23 sites at four depths (0m, n=166), (0.10m, n=139), 0.45-0.60m, n=117, (1.35-1.50m, n=117) under less disturbed forest (Forest), disturbed production forest of various local species (Degraded Forest) and tree-plantations (Acacia auriculiformes, 7-10years old, Tectona grandis, ∼25-30years old, Casuarina equisetifolia, 12years old) in the Uttar Kannada district, Karnataka, India, in the Western Ghats. The sampling strategy was also undertaken across three physiographic blocks and under three main soil types. Subsequently the determined K* were then linked with rainfall intensity-duration-frequency (IDF) characteristics to infer the dominant stormflow pathways.The Degraded Forest shows an order of magnitude decline in K* at the surface as result of human impacts at decadal to century time scales. The lowest surface permeability is associated with the Degraded Forests over the Laterite (Eutric Nitosols and Acrisols) and Red soils (Eutric Nitosols) and infiltration-excess overland flow, IOF probably occurs. Further there is a progressive decline in K* with depth in these soils supporting Degraded Forests. The A. auriculiformes plantations over the Red and Lateritic soils are progressively restoring the near-surface K*, but their K* still remain quite low when compared to the less disturbed forest permeability. Consequently these plantations still retain the 'memory' from the previous degraded state. In contrast the permeability of the Black soils (Vertisols) are relatively insensitive to T. grandis plantations and this soil group has a very low K*, irrespective of land cover, so that IOF likely prevails. Overall, the Laterites are the most variable in K* when compared to the other soil groups. Thus when compared to other studies, IOF is probably more prevalent in this region. More especially so, when taking into account the marked reduction in surface K* during the wet season when compared to dry season measurements. In addition, we have demonstrated the potential for the 'infiltration - trade-off' hypothesis to be realized in this landscape under certain conditions of land degradation and restoration. It is most relevant to the combination of degraded sites and A. auriculiformes plantations on Red or Laterite soils using the less disturbed forests as the baseline. The intensity of forest use and effects of monoculture plantations on soil ecology (relative to native, mixed forests) is likely to be the critical factor in affecting surface K* over time. Predicted changes in the intensity of rain events in the future is likely to enhance overland flow on degraded sites on all soils and especially on Black soils, and restoration efforts by all stake-holders, preferably using native or non-invasive species, are needed to address this concern. © 2010 Elsevier B.V.


Crone E.E.,Harvard University | Ellis M.M.,University of Montana | Morris W.F.,Duke University | Stanley A.,Institute for Applied Ecology | And 16 more authors.
Conservation Biology | Year: 2013

Uncertainty associated with ecological forecasts has long been recognized, but forecast accuracy is rarely quantified. We evaluated how well data on 82 populations of 20 species of plants spanning 3 continents explained and predicted plant population dynamics. We parameterized stage-based matrix models with demographic data from individually marked plants and determined how well these models forecast population sizes observed at least 5 years into the future. Simple demographic models forecasted population dynamics poorly; only 40% of observed population sizes fell within our forecasts' 95% confidence limits. However, these models explained population dynamics during the years in which data were collected; observed changes in population size during the data-collection period were strongly positively correlated with population growth rate. Thus, these models are at least a sound way to quantify population status. Poor forecasts were not associated with the number of individual plants or years of data. We tested whether vital rates were density dependent and found both positive and negative density dependence. However, density dependence was not associated with forecast error. Forecast error was significantly associated with environmental differences between the data collection and forecast periods. To forecast population fates, more detailed models, such as those that project how environments are likely to change and how these changes will affect population dynamics, may be needed. Such detailed models are not always feasible. Thus, it may be wiser to make risk-averse decisions than to expect precise forecasts from models. © 2013 Society for Conservation Biology.


Atkore V.M.,Suri Sehgal Center for Biodiversity and Conservation | Knight J.D.M.,Flat l | Devi K.R.,No. 16 | Krishnaswamy J.,Suri Sehgal Center for Biodiversity and Conservation
Copeia | Year: 2015

Pethia 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. © 2015 by the American Society of Ichthyologists and Herpetologists.


Ghosal S.,Norwegian University of Life Sciences | Skogen K.,Norwegian Institute for Nature Research | Krishnan S.,Suri Sehgal Center for Biodiversity and Conservation
Conservation and Society | Year: 2015

People's reactions to large carnivores take many forms, ranging from support and coexistence to resistance and conflict. While these reactions are the outcome of many different factors, in this paper we specifically explore the link between social constructions of landscapes and divergent responses to large carnivore presence. We compare case studies from four different landscapes shared by people and large carnivores, in India and Norway. We use social construction of landscapes as a key concept to explore responses to large carnivores in the context of ecological, economic, social, and cultural changes in these areas. Based on this comparison, we argue that the process of change is complex, with a plurality of responses from the groups affected by it. The response to large carnivore presence is influenced by many different factors, of which the interpretation of change-particularly landscape change-plays a significant role.Copyright: © Khumalo and Yung 2015.


Aravind N.A.,Suri Sehgal Center for Biodiversity and Conservation | Rao D.,Suri Sehgal Center for Biodiversity and Conservation | Rao D.,University of Veracruz | Ganeshaiah K.N.,Suri Sehgal Center for Biodiversity and Conservation | And 4 more authors.
Tropical Ecology | Year: 2010

Lantana camara is an invasive species that is widespread in India. Using birds as an indicator taxon, we investigated whether Lantana invasion was correlated with changes in ecosystem health of the moist and dry deciduous forests at the Malé Madeshwara Hills, Karnataka. We studied Lantana at four densities, low, medium, and high, and a no-Lantana control. Bird species diversity, species richness, and abundance were lower at high densities of Lantana in both forest types. Evenness increased with increase in Lantana density. To better understand the observed changes in bird community composition, we segregated birds into 2 guild types: microhabitat guilds and foraging guilds. An increase in Lantana density was correlated with a decline in canopy birds (of the canopy microhabitat guilds) and insectivores (of the insectivore foraging guilds). Our results suggest that Lantana affects the structure of the bird community by decreasing diversity, and that Lantana affects certain guilds more than others. © International Society for Tropical Ecology.


Ganesan R.,Suri Sehgal Center for Biodiversity and Conservation
Rheedea | Year: 2011

Litsea kakkachensis R. Ganesan, a new species of Lauraceae from Agasthyamalai hills, southern Western Ghats is described with illustration. It differs from its allied species L. venulosa (Meisn.) Hook.f. in number of lateral nerves, fl oral characters and shape of the fruit. The habitat, phenology, abundance and threat status are also discussed.


Krishnaswamy J.,Suri Sehgal Center for Biodiversity and Conservation | John R.,Suri Sehgal Center for Biodiversity and Conservation | John R.,Indian Institute of Science | Joseph S.,Center for International Forestry Research
Global Change Biology | Year: 2014

Global climate change has emerged as a major driver of ecosystem change. Here, we present evidence for globally consistent responses in vegetation dynamics to recent climate change in the world's mountain ecosystems located in the pan-tropical belt (30°N-30°S). We analyzed decadal-scale trends and seasonal cycles of vegetation greenness using monthly time series of satellite greenness (Normalized Difference Vegetation Index) and climate data for the period 1982-2006 for 47 mountain protected areas in five biodiversity hotspots. The time series of annual maximum NDVI for each of five continental regions shows mild greening trends followed by reversal to stronger browning trends around the mid-1990s. During the same period we found increasing trends in temperature but only marginal change in precipitation. The amplitude of the annual greenness cycle increased with time, and was strongly associated with the observed increase in temperature amplitude. We applied dynamic models with time-dependent regression parameters to study the time evolution of NDVI-climate relationships. We found that the relationship between vegetation greenness and temperature weakened over time or was negative. Such loss of positive temperature sensitivity has been documented in other regions as a response to temperature-induced moisture stress. We also used dynamic models to extract the trends in vegetation greenness that remain after accounting for the effects of temperature and precipitation. We found residual browning and greening trends in all regions, which indicate that factors other than temperature and precipitation also influence vegetation dynamics. Browning rates became progressively weaker with increase in elevation as indicated by quantile regression models. Tropical mountain vegetation is considered sensitive to climatic changes, so these consistent vegetation responses across widespread regions indicate persistent global-scale effects of climate warming and associated moisture stresses. © 2013 John Wiley & Sons Ltd.


Seshadri K.S.,Suri Sehgal Center for Biodiversity and Conservation | Gururaja K.V.,Indian Institute of Science | Aravind N.A.,Suri Sehgal Center for Biodiversity and Conservation
Zootaxa | Year: 2012

A new species of the shrub frog genus Raorchestes Biju, Souche, Dubois, Dutta and Bossuyt is described as Raorchestes kakachi sp. nov. from Agastyamalai hill region in the southern Western Ghats, India. The small sized Raorchestes (male: 24.7-25.8 mm, n = 3 and female: 24.3-34.1 mm, n = 3) is distinguished from all other known congeners by the following suite of characters. Snout oval in dorsal view; tympanum indistinct; head wider than long; moderate webbing in feet; colour on dorsum varying from ivory to brown, blotches of dark brown on flanks, brown mottling on throat reducing towards vent; inner and outer surface of thigh, inner surface of shank and inner surface of tarsus with a distinct dark brown horizontal band which extends upto first three toes on upper surface. A detailed description, advertisement call features, ecology, natural history notes and comparison with closely related species are provided for the new species. Copyright © 2012 · Magnolia Press.


PubMed | Suri Sehgal Center for Biodiversity and Conservation
Type: Journal Article | Journal: Journal of plant research | Year: 2016

The center of diversity of Piper nigrum L. (Black Pepper), one of the highly valued spice crops is reported to be from India. Black pepper is naturally distributed in India in the Western Ghats biodiversity hotspot and is the only known existing source of its wild germplasm in the world. We used ecological niche models to predict the potential distribution of wild P. nigrum in the present and two future climate change scenarios viz (A1B) and (A2A) for the year 2080. Three topographic and nine uncorrelated bioclim variables were used to develop the niche models. The environmental variables influencing the distribution of wild P. nigrum across different climate change scenarios were identified. We also assessed the direction and magnitude of the niche centroid shift and the change in niche breadth to estimate the impact of projected climate change on the distribution of P. nigrum. The study shows a niche centroid shift in the future climate scenarios. Both the projected future climate scenarios predicted a reduction in the habitat of P. nigrum in Southern Western Ghats, which harbors many wild accessions of P. nigrum. Our results highlight the impact of future climate change on P. nigrum and provide useful information for designing sound germplasm conservation strategies for P. nigrum.


PubMed | Suri Sehgal Center for Biodiversity and Conservation
Type: Journal Article | Journal: PloS one | Year: 2015

The Giant African Snail (Achatina fulica) is considered to be one the worlds 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.

Loading Suri Sehgal Center for Biodiversity and Conservation collaborators
Loading Suri Sehgal Center for Biodiversity and Conservation collaborators