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Asian elephants (Elephas maximus) are globally endangered, and their populations persist in several meta‐populations within fragmented landscapes across their distribution. Developing landscape‐level management plans for elephants requires reliable information on the pattern and determinants of their distribution across relevant spatial and temporal scales. The Brahmagiri‐Nilgiri‐Eastern Ghats Landscape (Nilgiri landscape) of peninsular India supports the largest breeding population of Asian elephants globally. The Wayanad Plateau, a wet forest tract in the dry forest‐dominated Nilgiri landscape, witnessed extensive forest fragmentation recently and evolved as a forest‐agriculture matrix. We predicted that habitat use by elephants in the Wayanad Plateau would be high during summer because of the availability of numerous perennial streams and associated swamps that retain water and soil moisture for plant growth over the dry season. We also hypothesized that elephants would use areas with greater forest cover that are removed from human settlements. We used an occupancy‐based approach that accounts for detection probability to understand factors influencing habitat use by elephants in summer (low rainfall, high temperature) and post‐monsoon (largely rainless winter conditions but with abundant forage and water) in 2019 and 2020. As expected, the intensity of habitat use was higher during the summer than during the post‐monsoon season. Elephants used habitats near perennial water sources and with greater forest cover, avoiding areas with high human disturbances. We emphasize the importance of areas that provide key resources for elephants during resource scarcity and the need to prevent habitat degradation for long‐term persistence of elephants and mitigation of human–elephant conflict. [ABSTRACT FROM AUTHOR]

Old world fruit bats are important seed dispersers of forest plants as well as of commercial fruit crops. Bats scatter seeds across landscapes and also aggregate (clump) seeds under feeding and roosting trees. In agroforestry landscapes, bat frugivory and seed dispersal can result in simultaneous accrual of socio‐economic benefits and costs to humans, which may be further affected by human health risks from zoonotic spillover through human–bat interactions. In our study, we used an integrated approach to assess socio‐economic benefits (from seed dispersal) and costs (from frugivory) from bats, in relation to latent zoonotic risk. We carried out the study in five agroforestry landscapes along India's Western Ghats, for selected commercial fruit crops (cashew, areca, banana and other pulpy/fleshy fruits). Specifically, we hypothesized that people's perceptions of benefits from fruit bats would be correlated with measured extents of clumped seed dispersal in fruit plantations. We conducted ecological studies to investigate the effects of fruit crop type and plantation attributes on clump‐dispersal, and in turn, on perceived 'net benefits' assessed from interviews with plantation‐associated people. We then explored associations between perceived socio‐economic net benefits and spatial data on disease risk factors for fruit bat‐linked henipavirus transmission. We found that the extent of bat‐mediated clump‐dispersal was highest for cashew, especially in isolated plantations. People's perceptions of benefits from fruit bats matched the measured extents of clump‐dispersal of cashew and areca. These benefits came with some costs from scatter‐dispersal and damage to other fleshy fruits from frugivory by bats. Interestingly, we did not detect tradeoffs between perceived net benefits from bats and disease risk, which is of significance for bat conservation and its implications for human well‐being. Overall, our results highlight that bat‐mediated seed dispersal needs to be sustained as an important ecosystem service, despite some latent zoonotic risk, in the Anthropocene [ABSTRACT FROM AUTHOR]

Small hydropower projects (SHPs) are promoted as low‐impact alternatives for large hydropower. SHPs are generally commissioned on small‐ to medium‐sized mountainous rivers, often in biodiverse regions, with backing in the form of subsidies, facultative policies and exemption from impact assessments as they are considered 'green'. However, the ecological impacts of SHPs are understudied especially in highly seasonal tropical streams of Western Ghats of India, a global biodiversity hotspot and a distinct freshwater fish eco‐region. We compared SHP‐affected segments of a dammed and an undammed river in the Western Ghats of Karnataka, to assess how altered flow regime affects seasonal variability in habitat and water quality, and influences fish assemblage structure. We found that flow alteration by the SHP varied between different segments of the dammed river and with season. Furthermore, the nature of flow alteration influenced habitat variability, water quality and fish assemblage response in the dammed river. We observed that the dewatered segment of the dammed river experienced a lotic to lentic shift in habitat and water quality, which favoured fish species with eurytopic affinities. Fluctuating flows in the downstream segment subdued natural variability in flow regime and created novel habitats and water‐quality conditions, affecting fish assemblages. The upstream segment of the dammed river retained natural variability in habitat and water quality, but did not mimic the undammed river in terms of fish composition. We also observed potential constraints on recruitment for migratory species of fish in the dammed river. Based on our results, we suggest how the placement of dewatered segment, and timing the closure of SHP operation in dry season based on ecological thresholds are potential solutions to mitigate the impacts of the SHPs. Furthermore, we recommend effective impact assessments, and adaptive management with active interventions to maintain genetic and ecological connectivity, as key to enhance the sustainability of the SHPs. [ABSTRACT FROM AUTHOR]

Abstract: Small hydropower projects (SHPs) are promoted as environmentally benign alternatives to larger dams; however, the impacts of SHPs have been poorly studied, especially in tropical developing countries, where their growth is being encouraged. This study assessed the impacts of two SHPs on freshwater fish communities in the Western Ghats biodiversity hotspot of India. Two dammed and one undammed tributary of the Netravathi River, having similar stream order, elevation, and surrounding land‐use types, were identified as test and control sites respectively. Stream geometry, water chemistry, and fish assemblages were compared across upstream, dewatered, and downstream location categories within and across the three streams. Flow alterations induced by SHPs affected the dewatered river stretches most severely. Stream wetted width and depths diminished drastically in dammed dewatered segments, and consequently this region was characterized by elevated water temperature and reduced dissolved oxygen. Fish species composition varied significantly between dammed and undammed sites, across the upstream, dewatered, and downstream location categories. Dammed segments had lower fish species richness, diversity, and endemicity, and were dominated by eurytopic species (adapted to lentic conditions), unlike the control site, which was dominated by rheophilic species (adapted to flowing waters). Regression analyses indicated that fish species richness in dammed streams increased with distance from the dam in the upstream direction. The SHPs were found to have severe impacts on stream geometry, water chemistry, and aquatic biota, especially in the dry season. Given the ambitious targets of planned SHP growth, most of which are within ecologically fragile regions, changes in SHP operations and policies are proposed to enable the conservation of river fish diversity. These include mandatory environmental impact assessments, conserving undammed headwater streams in regulated basins, maintaining adequate environmental flows, and implementing other mitigation measures. [ABSTRACT FROM AUTHOR]

• Streamflow is generated more quickly in grasslands invaded by exotic plants during extreme rain and may contribute to floods. • Canopy cover, antecedent moisture and drainage density determine magnitude of rainfall-runoff response during extreme events. • Hydrologic footprint of exotic invasive plants such as wattle have consequences for ecosystems and human well-being. Invasive trees in catchments around the world are a source of concern due to their hydrological and ecological impacts. A large number of studies have focused on their impact on dry-season stream discharge due to enhanced transpiration. The impact of invasive trees on stream discharge and flood risk during extreme rain events, which are becoming more frequent due to climate change, has not been addressed adequately. We examined the influence of land-cover, canopy cover, and other catchment morphological characteristics on stream discharges in hilly catchments during light, heavy, and extreme rain events. Three years of rainfall-runoff observations, between January 2014 and December 2016, were collected in eleven neighbouring mountainous catchments in Nilgiris, South India. Each catchment had a distinct land cover, namely shola forests, montane grasslands, and catchments invaded by wattle (Acacia mearnsii). Hourly rain intensities between the percentiles 25–90, 90–95 and over 95 were categorised as light, heavy and extreme respectively, and were used to study hourly peak stream discharge responses. We compared discharge between native grassland catchments and grassland catchments invaded by wattle. Discharge rates were corrected for the catchment area. We found that land cover and canopy-cover influenced the hydrologic response to extreme rain events. Regression models with flood event as the response variable suggested an increase in rainfall-runoff response with an increase in canopy cover. The maximum hourly discharge observed in the reference grassland catchment (0.00098 mm s−1) was lower than the maximum discharge observed in low density (0.00529 mm s−1) and high density (0.00497 mm s−1) wattle catchments. At higher discharges, the flood magnitude in wattle invaded catchments was much greater than that in the grassland catchment for a given flood frequency – indicating a higher risk of severe flooding in wattle-dominated catchments. We attribute the enhanced flood discharges to the effects of spreading wattle roots on the enhancement of rapid, shallow sub-surface flows in invaded catchments. Catchments dominated by shallow sub-surface flows are known to have reduced water retention times in response to high rain intensities. Antecedent moisture conditions and drainage density were other factors that influenced the local rainfall-runoff relationships. In the Western Ghats and other parts of India grasslands have been planted with exotic woody trees, and some have become invasive. Our study indicates that replacing grasslands with woody plants at landscape scales, could affect hydrological processes and could increase flood risks during the monsoon, especially in mountainous regions. Management of invaded catchments by regulation of wattle and restoration of semi-natural grassland, combined with the installation of early warning systems in these impacted areas will help reduce flood risk during extreme rain under climate change. [ABSTRACT FROM AUTHOR]

Summary: The effects of forest degradation and use and establishment of tree-plantations on degraded or modified forest ecosystems at multi-decadal time-scales using tree-plantations on the streamflow response are less studied in the humid tropics when compared to deforestation and forest conversion to agriculture. In the Western Ghats of India (Uttar Kannada, Karnataka State), a previous soil hydraulic conductivity survey linked with rain IDF (intensity–duration–frequency) had suggested a greater occurrence of infiltration-excess overland within the degraded forest and reforested areas and thus potentially higher streamflow (Bonell et al., 2010). We further tested these predictions in Uttar Kannada by establishing experimental basins ranging from 7 to 23ha across three ecosystems, (1) remnant tropical evergreen Forest (NF), (2) heavily-used former evergreen forest which now has been converted to tree savanna, known as degraded forest (DF) and (3) exotic Acacia plantations (AC, Acacia auriculiformis) on degraded former forest land. In total, 11 basins were instrumented (3 NF, 4 AC and 4 DF) in two geomorphological zones, i.e., Coastal and Up-Ghat (Malnaad) and at three sites (one Coastal, two Up-Ghat). The rainfall–streamflow observations collected (at daily and also at a 36min time resolutions in the Coastal basins) over a 2–3year period (2003–2005) were analysed. In both the Coastal and Up-Ghat basins, the double mass curves showed during the rainy season a consistent trend in favour of more proportion of streamflow in the rank order DF>AC>NF. These double mass curves provide strong evidence that overland flow is progressively becomes a more dominant stormflow pathway. Across all sites, NF converted 28.4±6.41stdev% of rainfall into total streamflow in comparison to 32.7±6.97stdev% in AC and 45.3±9.61stdev% in DF. Further support for the above trends emerges from the quickflow ratio QF /Q for the Coastal basins. There are much higher values for both the DF and AC land covers, and their rank order DF>AC>NF. The quickflow response ratio QF /P is also the highest for the DF basin, and along with the QF /Q ratio, can exceed 90%. The corresponding delayed flow response ratios, QD /P clearly show the largest QD yields as a proportion of event precipitation from the Forest (NF1). The application of linear model supported these differences (e.g. 10–36% difference between NF and DF, p <0.001) in the storm hydrologic response of the Coastal basins. The exception was QF /P where there was a higher uncertainty connected with inter-basin mean differences. Cross-correlation plots for rain–streamflow and corresponding lag regression models for three storm events in the Coastal basins suggested the existence of alternative stormflow pathways with multiple lags with peaks between ∼12 and 24h in NF, compared to respective bimodal peaks at ∼1 and 16h in AC and ∼1 and 12h in DF. The long time lags for NF are suggestive of deep subsurface stormflow and groundwater as the contributing sources to the storm hydrograph. The short time lags in DF and AC are indicative of overland flow and so ‘memory’ of the previous degraded land cover is retained in AC as supported by previous hydraulic conductivity data. As potential and actual evapotranspiration is likely to be depressed during the monsoon, differences in streamflow and run-off responses between land-cover types is largely attributed to differences in soil infiltration and hydrologic pathways. Enhancing infiltration and reducing run-off in managed ecosystems should be explored in the terms of the context of other ecosystem services and biodiversity. [Copyright &y& Elsevier]

Abstract: A critical handicap to tropical biodiversity conservation efforts in agroecosystems is the unknowns regarding the influence of landscape-scale factors on the persistence of species. To address these uncertainties, we explored two essential landscape-scale questions, within India’s biologically-rich Western Ghats, examining two nearby human-dominated landscapes that dramatically differed in their pattern of land cover. First, how does the proximity of intact forest patches affect bird community composition within agricultural landscapes? Second, can simple remote sensing-derived measures (brightness, wetness, and NDVI) be used to estimate native bird species composition within those landscapes? In both landscapes, as distance to intact forest decreased, the similarity in bird community composition between agricultural areas and intact forest increased. This suggests that the retention of tropical forest bird communities within human-dominated landscapes critically depends on the maintenance of nearby intact forest. In an answer to the second question, the remote sensing measures correlated with forest-affiliated avian species richness in only one of the two landscapes, reflecting an ecological difference between the two in the response of forest bird species to local agricultural conditions. In the landscape where a correlation was found, there was high variation in vegetative structure, which strongly impacted both the remote sensing measures and forest bird species richness. In the other landscape, forest species richness strongly correlated with changes in tree species composition in the agriculture, a factor that could not be detected by the remote sensing metrics. In order to successfully conserve biodiversity in tropical agricultural landscapes, our findings show that it is essential to conserve intact forest within those landscapes and to understand the effect of local agricultural practices on species. [ABSTRACT FROM AUTHOR]

Abstract: Human-modified tropical landscapes under semi-natural or agro-ecosystems often harbor biodiversity of significant conservation value. In the Western Ghats of India, these ecosystems also provide connectivity between protected areas and other remnant forests. We investigated the conservation value of these landscapes and agro-ecosystems using results from 35 studies covering 14 taxonomic groups. Large, conspicuous taxonomic groups and tree-covered land-use types have received much focus in this area of research in the Western Ghats. We computed a response ratio defined as the log ratio of species richness in human land use to species richness in forest control site from 17 studies. In a meta-analysis, we investigated variation of this ratio across studies with respect to three variables: taxonomic group, the land-use type sampled and the extent of forest cover within the study landscape. Higher forest cover within the landscape emerged as a major positive influence on biodiversity in human-modified landscapes for vertebrates and vegetation while no patterns emerged for invertebrates. Our results suggest that loss of remnant forest patches from these landscapes is likely to reduce biodiversity within agro-ecosystems and exacerbate overall biodiversity loss across the Western Ghats. Conservation of these remnant forest patches through protection and restoration of habitat and connectivity to larger forest patches needs to be prioritized. In the densely populated Western Ghats, this can only be achieved by building partnerships with local land owners and stakeholders through innovative land-use policy and incentive schemes for conservation. [ABSTRACT FROM AUTHOR]

Abstract: Areas of high conservation value were identified in the Western Ghats using a systematic conservation planning approach. Surrogates were chosen and assessed for effectiveness on the basis of spatial congruence using Pearson’s correlations and Mantel’s tests. The surrogates were, threatened and endemic plant and vertebrate species, unfragmented forest areas, dry forests, sub-regionally rare vegetation types, and a remotely sensed surrogate for unique evergreen ecosystems. At the scale of this analysis, amphibian richness was most highly correlated with overall threatened and endemic species richness, whereas mammals, especially wide-ranging species, were better at capturing overall animal and habitat diversity. There was a significant relationship between a remote sensing based habitat surrogate and endemic tree diversity and composition. None of the taxa or habitats served as a complete surrogate for the others. Sites were prioritised on the basis of their irreplaceability value using all five surrogates. Two alternative reserve networks are presented, one with minimal representation of surrogates, and the second with 3 occurrences of each species and 25% of each habitat type. These networks cover 8% and 29% of the region respectively. Seventy percent of the completely irreplaceable sites are outside the current protected area network. While the existing protected area network meets the minimal representation target for 88% of the species chosen in this study and all of the habitat surrogates, it is not representative with regard to amphibians, endemic tree species and small mammals. Much of the prioritised unprotected area is under reserve forests and can thus be incorporated into a wider network of conservation areas. [Copyright &y& Elsevier]

Monsoon climate over India has high degree of spatio-temporal heterogeneity characterized by the existence of multi-climatic zones along with strong intra-seasonal, seasonal, and inter-annual variability. Vegetation growth of Indian forests relates to this climate variability, though the dependence structure over space and time is yet to be explored. Here, we present a comprehensive analysis of this association with quality-controlled satellite-based remote sensing dataset of vegetation greenness and radiation along with station based gridded precipitation datasets. A spatio-temporal time-frequency analysis using wavelets is performed to understand the relative association of vegetation growth with precipitation and radiation at different time scales. The inter-annual variation of forest greenness over the Tropical India are observed to be correlated with the seasonal monsoon precipitation. However, at inter and intra-seasonal scales, vegetation has a strong association with radiation in regions of high precipitation like the Western Ghats, Eastern Himalayas, and Northeast hills. Forests in Western Himalayas were found to be correlated more on the winter precipitation from western disturbances than the south west monsoon precipitation. Our results provide new and useful region-specific information for dynamic vegetation modelling in the Indian monsoon region that may further be used in understanding global vegetation-land-atmosphere interactions. [ABSTRACT FROM AUTHOR]

Forest reserves are increasingly becoming isolated, embedded in a matrix of various kinds of human land-use. Coffee plantations form the dominant matrix around many forest reserves in the tropics. In such a situation, the species richness and abundance of animals in coffee plantations can be expected to be determined by their proximity to the forest reserve and characteristics of the local vegetation. We tested this hypothesis with data on mammals (excluding bats, murids and insectivores) collected from 15 coffee plantations around the Bhadra Wildlife Sanctuary in the Western Ghats mountain ranges in India, between December 2005 and May 2006. We estimated mammal species richness and abundance from indirect evidence in belt transects and track plots, and from sightings during night surveys. We sampled the vegetation of the plantations from 36 plots of 5m×5m, in each estate. Twenty-eight species of mammals were recorded from 15 plantations. The number of species recorded in individual estates ranged from 5 to 19, with an average of 11.8. Distance from the Sanctuary was the most important factor that negatively influenced species richness, and the abundance of many species. Local vegetation characteristics influenced only the abundance of some small species. Coffee plantations can be a buffer around forest reserves and improve connectivity between them. However, increasing conversion of native shade into silver oak and hunting are two issues that must be addressed if coffee plantations are to form high-quality matrix around forest reserves in the Western Ghats. [Copyright &y& Elsevier]

Summary: 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. [Copyright &y& Elsevier]

Human land use and activity results in the loss of habitat and biodiversity, and alters how animals move through landscapes. Spatially explicit information on where animal movement is affected at large spatial scales is crucial for prioritizing conservation efforts. We evaluated landscape permeability to movement in two conservation priority landscapes in India, the Western Ghats (WG) and Central India (CI). Using an agent-based model we simulated movement and dispersal of five wide-ranging species in WG (elephant, gaur, leopard, sambar and sloth bear) and four in CI (gaur, leopard, sambar and sloth bear). For each species we compared movement in the presence and absence of land-use land-cover, infrastructure and human population to identify areas where movement is impeded and reduced due to high-resistance features; unrestricted due to relatively low-resistance features; and increased and channelled due to surrounding high-resistance areas. In both landscapes, median movement was reduced. Human land-use, human population and high linear infrastructure density contribute the highest to impeded movement for all species. Natural areas constitute only 20–55% and 50–70% of unrestricted, increased and channelled movement areas in WG and CI respectively. This suggests that a large percentage of the landscape crucial for maintaining movement is not completely permeable. Such areas are often neglected in conservation planning. Our spatially explicit results help identify and prioritize areas where restoration or mitigation should be planned to improve permeability to movement for large mammals. Our approach can be used for other landscapes where data on large mammal movement is lacking. • Median permeability to movement for all species in both landscapes was reduced. • Reduced movement is due to human land-use, human population and linear infrastructure. • Natural areas occupy only 20–55% of high permeability areas in WG and 50–70% in CI. • Thus permeability is not complete in areas crucial for movement. • Our spatially explicit results help prioritize restoration and mitigation measures. [ABSTRACT FROM AUTHOR]