India has experienced significant Land-Use and Land-Cover Change (LULCC) over the past few decades. In this context, careful observation and mapping of LULCC using satellite data of high to medium spatial resolution is crucial for understanding the long-term usage patterns of natural resources and facilitating sustainable management to plan, monitor and evaluate development. The present study utilizes the satellite images to generate national level LULC maps at decadal intervals for 1985, 1995 and 2005 using onscreen visual interpretation techniques with minimum mapping unit of 2.5 hectares. These maps follow the classification scheme of the International Geosphere Biosphere Programme (IGBP) to ensure compatibility with other global/regional LULC datasets for Remote Sens. 2015, 7 2403 comparison and integration. Our LULC maps with more than 90% overall accuracy highlight the changes prominent at regional level, i.e., loss of forest cover in central and northeast India, increase of cropland area in Western India, growth of peri-urban area, and relative increase in plantations. We also found spatial correlation between the cropping area and precipitation, which in turn confirms the monsoon dependent agriculture system in the country. On comparison with the existing global LULC products (GlobCover and MODIS), it can be concluded that our dataset has captured the maximum cumulative patch diversity frequency indicating the detailed representation that can be attributed to the on-screen visual interpretation technique. Comparisons with global LULC products (GlobCover and MODIS) show that our dataset captures maximum landscape diversity, which is partly attributable to the on-screen visual interpretation techniques. We advocate the utility of this database for national and regional studies on land dynamics and climate change research. The database would be updated to 2015 as a continuing effort of this study.
Background: The State of Arunachal Pradesh is part of the Himalaya biodiversity hotspots distributed over an area with the largest elevation gradients in the world, ranging from lowland tropical forests to alpine vegetation. Methods: The vegetation was surveyed along an elevation gradient ranging from 87 to 4161 m in 354 belt transects (500 m × 10 m in size) and analyzed using various ecological indices. Results: A total of 482 (458 identified, 24 unidentified) plants were recorded in the present study, of which 153 are nonwoody herbs and grasses (145 identified) belonging to 55 families, and 329 are woody trees and shrubs (313 identified) belonging to 74 families. The 458 identified species belong to 117 families and 251 genera, of which 94.10% are phenerogams (Angiosperms: 421 species [spp.] and Gymnosperms: 10 spp.) and 5.90% cryptogams (Pteridophytes: 27 spp.). The family Fabaceae contributed the greatest species diversity with a total of 27 plant species (Papilionaceae: 10 spp., Mimosaceae: 9 spp. and Caesalpinaceae: 8 spp.) followed by Poaceae (21 spp.), Ericaceae (20 spp.), Asteraceae (18 spp.), Lauraceae (17 spp.), Euphorbiaceae (16 spp.), Urticaceae (15 spp.) and 49 monotypic families. The most dominant trees were Castanopsis indica (24 individuals per ha), followed by Quercus semicarpifolia (12 individuals per ha) and Pinus roxburghii (12 individuals per ha) and some bamboos (Dendrocalamus strictus: 69 individuals per ha; Bambusa pallida: 16 individuals per ha). The studied forest stands were rich in various bamboos; a total of 14 different bamboos were recorded in the present study including Dendrocalamus strictus, Bambusa tulda, B. pallida etc. Common IUCN red-listed species were Aquilaria malaccensis, Begonia tessaricarpa, Gledetsia assamica, Gymnocladus assamicus, Livistona jenkinsiana, Rhododendron meddenii, Rhododendron thomsonii collected from the Dirrang, Tawang, Yamcha, Itanagar, Along and Mebo areas of Arunachal Pradesh.
Conclusion:The results confirm that the Eastern Himalayan forests are very rich in terms of species diversity which decreases with increasing elevation. Species richness and distribution patterns of plants are largely regulated by altitude and other environmental factors. Intensive monitoring and management is needed to protect this fragile ecosystem from the ever-increasing anthropogenic pressure and changing climatic conditions.
Abstract. Large-scale environmental gradients have been invaluable for unraveling the processes shaping the evolution and maintenance of biodiversity. Environmental gradients provide a natural setting to test theories about species diversity and distributions within a landscape with changing biotic and abiotic interactions. Elevational gradients are particularly useful because they often encompass a large climatic range within a small geographical extent. Here, we analyzed tree communities in plots located throughout Arunachal Pradesh, a province in northeast India located on the southern face of the Eastern Himalayas, representing one of the largest elevational gradients in the world. Using indices of species and phylogenetic diversity, we described shifts in community structure across the landscape and explored the putative biotic and abiotic forces influencing species assembly. As expected, species richness and phylogenetic diversity decreased with increasing elevation; however, contrary to predictions of environmental filtering, species relatedness did not show any clear trend. Nonetheless, patterns of beta diversity (both taxonomic and phylogenetic) strongly suggest lineage filtering along the elevational gradient. Our results may be explained if filtering is driving the assembly of species from distinct evolutionary lineages. New metrics exploring community contributions to regional taxonomic and phylogenetic beta diversity provided additional evidence for the persistence of unique communities at high elevations. We suggest that these patterns may be consistent with filtering on glacial relicts, part of once more diverse clades with convergent traits suited to climates at the last glacial maximum, resulting in random or over-dispersed community assemblages at high elevations. We propose that these high-elevation sites with evolutionarily distinct species represent possible regions for conservation priority that may provide refugia for species threatened by current warming trends.
Sustainability of wetland ecosystem is necessary for various important functions such as food storage, water quality continuation and providing habitat for different species of flora and fauna. Hence, an inventory of wetlands of any region is a pre-requisite for their conservation and management. This study has been carried out to delineate the change in freshwater lake of 'Deepor Beel' wetland of Assam, India, using LANDSAT TM data. Field observation shows that the ecosystem is facing both natural as well as anthropogenic threats. Rapid urbanization, Illegal settlements, industries, invasive species (Eichhornia crassipes) are the major cause of this wetland decline. It has been found that massive decline occurred between the period 1991 to 2001 i.e., 1.891 sq.km which was at the rate of -0.171 per year where as the decline between the period 2001 to 2010 was found to be 1.013 sq. km which was at a rate of -0.101. The total area of open water bodies has decreased by 2.904 sq. km from 1991 to 2010 i.e. 59.19%. Thus the overall rate of change in the water bodies from 1991 to 2010 to other land use categories was found to be -0.145. Hence the study reveals the potentiality of Landsat TM data mapping the change in the wetland ecosystem. It is further hoped that the study will have high utility in preparing management plan for conservation of this ecosystem.
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