No abstract

Animal-vehicle collision on the roads is a major cause of mortality of a wide range of animal taxa both within and around protected areas. This study has been conducted in the National Highway 715 (new) covering a continuous stretch of 64 km that passes through Kaziranga National Park (KNP) of Assam (India). The area falls between the boundary of KNP on its north and North Karbi Anglong Wildlife sanctuary on the south. The survey concentrated on the mortality study of four groups of vertebrates viz., amphibians, reptiles, birds, and mammals resulting from collisions with vehicles from October 2016 through September, 2017. A total of 6036 individual roadkills were registered, belonging to 53 species, 23 other taxa and 30 families of vertebrates, with herpetofauna being the most affected group followed by birds and mammals. The study evaluated seasonal variation in the overall roadkill pattern with highest mortality in the monsoon season 38.27% (n = 2310) and with peak casualties starting with the onset of rainfall (February and March) and during monsoons (July and August). The amphibian mortality was also found to be highest during the monsoon with 43.28% (n = 1575) of kills, as compared to the other three groups. NH-715 (new), therefore serves as a challenging passage for the animals, forming a major barrier for the faunal component of the Kaziranga-Karbi Anglong landscape. This study thus tried to reflect the often overlooked issue of roads and highways in terms of direct mortality of animals due to traffic and thereby can be helpful in understanding the seriousness of the situation and identifying prospective measures to be taken for sustainable coexistence of both animals and human.

The present study aimed at predicting the potential habitat of Western Hoolock Gibbon (Hoolock hoolock) in the upper Brahmaputra River Valley, Assam, India, and identifying priority conservation areas for the species, taking canopy cover into account. We used the maximum entropy algorithm for the prediction of the potential habitat of the gibbon using its current distribution with 19 environmental parameters as primary predictors. Spatio-temporal analyses of the habitat were carried out using satellite-based remote sensing and GIS techniques for two decades (1998–2018) along with Terra Modis Vegetation Continuous Field product to examine land use land cover (LULC), habitat fragmentation, Normalized Difference Vegetation Index (NDVI) and tree cover percentage of the study area. To identify the conservation priority area, we applied a cost-effective decision-making analysis using systematic conservation prioritization in R programming. The model predicted an area of 6025 km2 under high potential habitat, a major part of which was found to overlap with dense forest (80%), followed by moderately open forest (74%) and open forest (66%). The LULC change matrix showed a reduction of forest area in the predicted high potential habitat during the study period, while agricultural class showed an increasing trend. The fragmentation analysis indicated that the number of patches and patch density increased from 2008 to 2018 in the ‘very dense’ and ‘dense’ canopy regions of the gibbon habitat. Based on the conservation priority analysis, a 640 km2 area has been proposed to conserve a minimum of 10% of gibbon habitat. The current analysis revealed that in the upper Brahmaputra Valley most areas under dense forest and dense canopy have remained intact over the last two decades, at least within the high potential habitat zone of gibbons independent of the degree of area change in forest, agriculture and plantation.

The present study aimed at predicting the potential habitat of Western Hoolock Gibbon (Hoolock hoolock) in the upper Brahmaputra river valley, Assam and to identify the conservation priority areas for systematic conservation of the species taking canopy cover into account. We used the maximum entropy algorithm for the prediction of the potential habitat of Gibbons using its current distribution with 19 environmental parameters as primary predictors. Spatio-temporal analyses of the habitat were carried out using satellite-based remote sensing and GIS techniques for two decades (1998–2018) along with Terra Modis Vegetation Continuous Field product to examine the land use land cover (LULC), habitat fragmentation, Normalized Difference Vegetation Index (NDVI) and tree cover percentage of the study area. To identify the conservation priority area, we applied a cost-effective decision-making analysis using systematic conservation prioritization in R programming. The model predicted an area of 6025.1 km2 under high potential habitat, and a major part of it was found to overlap with the dense forest (80.04%) followed by moderately open forest (73.90%) and open forest (65.82%). The LULC change matrix showed deduction of forest areas in the predicted high potential habitat during the study period, while agricultural class showed an increasing trend. The fragmentation analysis indicated that the number of patches and patch density increased from 2008 to 2018 in the ‘very dense’ and ‘dense’ canopy regions of the gibbon habitat. Based on the conservation priority analysis, 640 km2 area has been proposed to conserve a minimum 10% of the gibbons’ habitat. The current analysis revealed that in Upper Brahmaputra Valley most of the areas under dense forest and dense canopy have remained intact over the last two decades, at least within the high potential habitat of gibbons independent of the degree of area change in forest, agriculture and plantation.