• C S Jha

      Articles written in Journal of Earth System Science

    • Landscape level assessment of critically endangered vegetation of Lakshadweep islands using geo-spatial techniques

      C Sudhakar Reddy Bijan Debnath P Hari Krishna C S Jha

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      The conservation of biodiversity is essential for human survival and quality of the environment. Lakshadweep islands are vulnerable to global change and the representing remnant natural vegetation. Landscape fragmentation, disturbance regimes and biological richness have been studied using geo-spatial techniques. Littoral vegetation is the only natural vegetation type of Lakshadweep islands. Altogether 59 patches of the littoral vegetation occupying an area of 137.2 ha were identified. 58.06% of the littoral vegetation patches belongs to the patch-size class of > 5 ha. The remnant natural vegetation surviving with patches of less than 20 ha size indicates severe anthropogenic pressure. The fragmentation of littoral vegetation habitat into smaller isolated patches poses one of the key threats to biodiversity and coastal environment. Phytosociological observations revealed distinct plant communities and presence of invasive species in littoral vegetation. The high disturbance areas accounted for 59.11% area of the total vegetation. The overall spatial distribution of biological richness (BR) in Lakshadweep shows maximum BR at low level (78%), followed by medium (19%), high (2%) and very high (1%). The study emphasizes the importance of conserving the remnant natural vegetation, which is critically endangered.

    • Landscape level analysis of disturbance regimes in protected areas of Rajasthan, India

      P Hari Krishna C Sudhakar Reddy Randeep Singh C S Jha

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      There is an urgent need to identify the human influence on landscape as disturbance regimes was realized for prioritization of the protected areas. The present study has attempted to describe the landscape level assessment of fragmentation and disturbance index in protected areas of Rajasthan using remote sensing and GIS techniques. Geospatial analysis of disturbance regimes indicates 61.75% of the total Pas are under moderate disturbance index followed by 28.64% and 9.61% under low and high, respectively. Among the 28 protected areas – National Chambal WLS, Jaisamand WLS, Kumbhalgarh WLS, Sawai Man Singh WLS, Kailadevi WLS and Bandh BarathaWLS are representing high level of disturbance. The present study has emphasized the moderate to low disturbance regimes in protected areas, which infer low biotic pressure and conservation effectiveness of PA network in Rajasthan. The spatial information generated on PAs is of valuable use for forest management and developing conservation strategies.

    • Satellite image based quantification of invasion and patch dynamics of mesquite (Prosopis juliflora) in Great Rann of Kachchh, Kachchh Biosphere Reserve, Gujarat, India

      S Vazeed Pasha K V Satish C Sudhakar Reddy P V V Prasada Rao C S Jha

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      The invasion of alien species is a significant threat to global biodiversity and the top driver of climate change. The present study was conducted in the Great Rann of Kachchh, part of Kachchh Biosphere Reserve, Gujarat, India, which has been severely affected by invasion of Prosopis juliflora. The invasive weed infestation has been identified using multi-temporal remote sensing datasets of 1977, 1990, 1999, 2005 and 2011. Spatial analyses of the transition matrix, extent of invasive colonies, patchiness, coalescence and rate of spread were carried out. During the study period of three and half decades, almost 295 km2 of the natural land cover was converted into Prosopis cover. This study has shown an increment of 42.9% of area under Prosopis cover in the Great Rann of Kachchh, part of the Kachchh Biosphere Reserve during 1977 to 2011. Spatial analysis indicates high occupancy of Prosopis cover with most of the invasion (95.9%) occurring in the grasslands and only 4.1% in other land cover types. The process of Prosopis invasion shows high patch initiation, followed by coalescence, indicating aggressive colonization of species. The number of patches within an area of > 1 km2 increased from 1977 to 2011, indicating the formation of new Prosopis habitats by replacing the grasslands. The largest patch of Prosopis cover increased from 144 km2 in 1977 to 430 km2 in 2011. The estimated mean patch size was 7.8 km2 in 1977. The mean patch size was largest during 2011, i.e., 9 km2. The annual spread rate for Prosopis has been estimated as 2.1% during 2005–2011. The present work has investigated the long term changes in Prosopis cover in the Great Rann of Kachchh, part of Kachchh Biosphere Reserve. The spatial database generated will be useful in preparing strategies for the management of Prosopis juliflora.

    • Assessment and monitoring of long-term forest cover changes (1920–2013) in Western Ghats biodiversity hotspot

      C Sudhakar Reddy C S Jha V K Dadhwal

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      Western Ghats are considered as one of the global biodiversity hotspots. There is an information gap on conservation status of the biodiversity hotspots. This study has quantified estimates of deforestation in the Western Ghats over a period of past nine decades. The classified forest cover maps for 1920, 1975, 1985, 1995, 2005 and 2013 indicates 95,446 (73.1%), 63,123 (48.4%), 62,286 (47.7%), 61,551 (47.2%), 61,511 (47.1%) and 61,511 km2 (47.1%) of the forest area, respectively. The rates of deforestation have been analyzed in different time phases, i.e., 1920–1975, 1975–1985, 1985–1995, 1995–2005 and 2005–2013. The grid cells of 1 km2 have been generated for time series analysis and describing spatial changes in forests. The net rate of deforestation was found to be 0.75 during 1920–1975, 0.13 during 1975–1985, 0.12 during 1985–1995 and 0.01 during 1995–2005. Overall forest loss in Western Ghats was estimated as 33,579 km2 (35.3% of the total forest) from 1920's to 2013. Land use change analysis indicates highest transformation of forest to plantations, followed by agriculture and degradation to scrub. The dominant forest type is tropical semi-evergreen which comprises 21,678 km2 (35.2%) of the total forest area of Western Ghats, followed by wet evergreen forest (30.6%), moist deciduous forest (24.8%) and dry deciduous forest (8.1%) in 2013. Even though it has the highest population density among the hotspots, there is no quantifiable net rate of deforestation from 2005 to 2013 which indicates increased measures of conservation.

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