P. S. Roy

Development of Decadal (1985–1995–2005) Land Use and Land Cover Database for India

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 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.

Forest Canopy Density Stratification: How Relevant is Biophysical Spectral Response Modelling Approach?

Abstract Monitoring of forest cover is an essential tool for sustainable management of natural resources. Woody green cover can better maintained and managed by identification of forest gaps and their subsequent refilling. Forest canopy density mapping is one of the tools used to identify such canopy openings and most useful parameter to consider in the planning and implementation of afforestation and reforestation program. The present study demonstrate the test‐assessment and practicability of forest canopy density mapping using satellite remote sensing data and biophysical spectral response modelling. Forest canopy density stratification through object oriented image analysis and conventional method of visual interpretation also have been compared with the Forest Canopy Density (FCD) Mapper semi expert system. In this study, forest canopy density is effectively stratified through linear multi‐parametric approach by utilizing advanced vegetation index, bare soil index, shadow index and thermal index. Isadata cluster analysis of forest canopy density map derived from FCD Mapper and conventional methods were shown similar results with respect to percent area of forest and non‐forest. The high percentage (10-30%) occurrence of bushy vegetation like Lantana Camera in ground canopy poses challenge in delineation of forest canopy density as its spectral reflectance is similar to that of the forest.

Connecting the dots: mapping habitat connectivity for tigers in central India

Large connected landscapes are paramount to maintain top predator populations. Across their range, tiger (Panthera tigris) populations occur in small fragmented patches of habitat, often isolated by large distances in human-dominated landscapes. We assessed connectivity between 16 protected areas (PAs) in central India, a global priority landscape for tiger conservation, using data on land use and land cover, human population density, and transportation infrastructure. We identified and prioritized movement routes using a combination of least-cost corridor modeling and circuit theory. Our analyses suggest that there are several opportunities to maintain connectivity in this landscape. We mapped a total of thirty-five linkages in the region and calculated metrics to estimate their quality and importance. The highest quality linkages as measured by the ratio of cost-weighted distance to Euclidean distance are Kanha–Phen/Bandhavgarh–SanjayGhasidas/Melghat–Satpura, and cost-weighted distance to least-cost path length are Nawegaon–Tadoba/Achanakmar–SanjayGhasidas/Kanha–Phen. We used current flow centrality to evaluate the contribution of each PA and linkage toward facilitating animal movement. Values are highest for Kanha and Pench tiger reserves, and the linkages between Kanha–Phen, Kanha–Pench, and Pench–Satpura, suggesting that these PAs and linkages play a critical role in maintaining connectivity in central India. In addition, smaller areas such as Bor, Nawegaon, and Phen have high centrality scores relative to their areas and thus may act as important stepping stones. We mapped pinch points, which are sections of the linkages where tiger movement is restricted due to unfavorable habitat, transportation networks, human habitation, or a combination of factors. Currently, very limited data exist on tiger movement outside of PAs to validate model results. Regional-scale connectivity mapping efforts can assist managers and policy makers to develop strategic plans for balancing wildlife conservation and other land uses in the landscape.

Forest fragmentation in the Himalaya: A Central Himalayan case study

Administrative divisions in the Great Southern Watershed of the Himalaya are diverse in terms of population density and forest cover. This study analyzed the spatial patterns of different attributes in the different Indian states and Himalayan kingdoms, and explored the extent and patterns of forest fragmentation in a Himalayan landscape as a case study. Of the total landscape in the case study area (3167 km2), 41% was fragmented. Homogenous landscape (59%) includes either continuous natural vegetation or a village landscape. Presence of two forest patches (38% of the total fragmented area) at a unit scale of about 0.5 km2 (525 × 525 m) was the most commonly occurring pattern but, in some parts, up to 13 patches were observed. Fragmentation of vegetation was visible even at smaller scales of landscape analysis. At a scale of 75 × 75 m, land division into three patches was observed. With an increase in the unit area of landscape analysis the number of patches per unit land area and the total fragmented area also increased. The forests that escaped fragmentation were either inaccessible to humans or had rigorous legal protection. Anthropogenic activities appeared to be one of the factors responsible for fragmentation but, natural factors also contributed.

Characterizing Shorea robusta communities in the part of Indian Terai landscape

Shorea robusta Gaertn. f. (Sal) is one of the important timber-yielding plants in India, which dominates the vegetation of Terai landscape of Uttar Pradesh state in India forming various communities based on its associations. The present study deals with delineation, mapping and characterization of various communities of Sal (Shorea robusta) forests in Terai landscape of Uttar Pradesh, India ranging across over 16 districts. Field survey and visual interpretation based forest vegetation type classification and mapping was carried out as part of the project entitled ‘Biodiversity characterization at landscape level using remote sensing and GIS’. Indian Remote Sensing-P6 (Resourcesat-1) Linear Imaging Self Scanner-III satellite data was used during the study. The total area covered by different Sal forests was found to be approximately 2256.77 km2. Sal communities were identified and characterized based on their spectral properties, physiognomy and phytosociological characteristics. Following nine Sal communities were identified, delineated and mapped with reasonable accuracy viz., Chandar, Damar, dry plains, moist plains, western alluvium, western alluvium plains, mixed moist deciduous, mixed dry deciduous and Siwalik. It is evident from the area estimates that mixed moist deciduous Sal is the most dominant community in the region covering around (1613.90 km2), other major communities were found as western alluvium plains Sal (362.44 km2), mixed dry deciduous Sal (362.44 km2) and dry plains Sal (107.71 km2). The Terai landscape of Uttar Pradesh faces tremendous anthropogenic pressure leading to deterioration of the forests. Community level information could be used monitoring the status as well as for micro level conservation and planning of the Sal forests in Terai Landscape of Uttar Pradesh.

Remote sensing based deforestation analysis in Mahanadi and Brahmaputra river basin in India since 1985

Land use and land cover (LULC) change has been recognized as a key driver of global climate change by influencing land surface processes. Being in constant change, river basins are always subjected to LULC changes, especially decline in forest cover to give way for agricultural expansion, urbanization, industrialization etc. We used on-screen digital interpretation technique to derive LULC maps from Landsat images at three decadal intervals i.e., 1985, 1995 and 2005 of two major river basins of India. Rain-fed, Mahanadi river basin (MRB) attributed to 55% agricultural area wherein glacier-fed, Brahmaputra river basin (BRB) had only 16% area under agricultural land. Though conversion of forest land for agricultural activities was the major LULC changes in both the basins, the rate was higher for BRB than MRB. While water body increased in MRB could be primarily attributed to creation of reservoirs and aquaculture farms; snow and ice melting attributed to creation of more water bodies in BRB. Scrub land acted as an intermediate class for forest conversion to barren land in BRB, while direct conversion of scrub land to waste land and crop land was seen in MRB. While habitation contributed primarily to LULC changes in BRB, the proximity zones around habitat and other socio-economic drivers contributed to LULC change in MRB. Comparing the predicted result with actual LULC of 2005, we obtained >97% modelling accuracy; therefore it is expected that the Dyna-CLUE model has very well predicted the LULC for the year 2025. The predicted LULC of 2025 and corresponding LULC changes in these two basins acting as early warning, and with the past 2-decadal change analysis this study is believed to help the land use planners for improved regional planning to create balanced ecosystem, especially in a changing climate.

Land-use and land-cover change in Western Ghats of India

The Western Ghats (WG) of India, one of the hottest biodiversity hotspots in the world, has witnessed major land-use and land-cover (LULC) change in recent times. The present research was aimed at studying the patterns of LULC change in WG during 1985–1995–2005, understanding the major drivers that caused such change, and projecting the future (2025) spatial distribution of forest using coupled logistic regression and Markov model. The International Geosphere Biosphere Program (IGBP) classification scheme was mainly followed in LULC characterization and change analysis. The single-step Markov model was used to project the forest demand. The spatial allocation of such forest demand was based on the predicted probabilities derived through logistic regression model. The R statistical package was used to set the allocation rules. The projection model was selected based on Akaike information criterion (AIC) and area under receiver operating characteristic (ROC) curve. The actual and projected areas of forest in 2005 were compared before making projection for 2025. It was observed that forest degradation has reduced from 1985–1995 to 1995–2005. The study obtained important insights about the drivers and their impacts on LULC simulations. To the best of our knowledge, this is the first attempt where projection of future state of forest in entire WG is made based on decadal LULC and socio-economic datasets at the Taluka (sub-district) level.

The Climate Change Conundrum and the Himalayan Forests: The Way Forward into the Future

The earth’s climate has always been changing, but with current rate of change, forests might not be able to adapt to rapid changes in climate variables, along with increased risk of extreme climate events. Climate change has significantly altered structure, composition and distribution patterns of forests across the globe. The Himalayan forests are sensitive to climate change impacts, but the extent and magnitude of potential response is still not well-understood. Climate change, however, cannot be considered as the only driving force responsible for changes in the type, distribution and coverage of vegetation, as other anthropogenic disturbances equally play a crucial role in accelerating the alterations in this region. With the impeding uncertainties involving climate change and increased dependence of communities on forests and forest-based resources, adaptation must be considered along with mitigation in the foreseeable future. The limited understanding of ecosystem dynamics in the Himalayan region poses a grand challenge for many research programmes in ecology and conservation. The scientific literature shows efforts to model species distribution based on current climate conditions and forecast species distribution based on future climate scenarios. These studies indicate the possibility of extinction and migration of many species; nonetheless, they fail to integrate human influence to changing environmental conditions. Addressing potential impacts of climate change is both urgent and difficult. The hypothesis foretelling the future requires much improvement in its forecasting skills in order to accurately predict the eventual fate for sustainable forest management.

Extraction of detailed level flood hazard zones using multi-temporal historical satellite data-sets – a case study of Kopili River Basin, Assam, India

ABSTRACT Kopili River Basin is one of the chronic flood affected basins of Brahmaputra River, lies in north-eastern part of India. This study attempts to utilize the historical spatial data on flood inundation layers derived from multi-temporal remote sensing images for identifying villages falling in various flood hazard severity zones. A total of 183 flood events were mapped in the basin in the last two decades. About 3.89 lakh hectares which is 29% of Kopili River Basin area is affected by floods during 1977, 1988 and 1998–2015. The flood hazard zonation frequency is determined treating each village as minimum unit of entity and based on the number of times affected by flood events in a given year. About 742 villages are categorized as very low to low and 396 villages fall in moderate flood hazard zone and more than 150 villages are categorized between high to very high flood hazard zones.

Spatial Patterns and Ecology of Shifting Forest Landscapes in Garo Hills, India

In many parts of the world, increasing rates of shifting cultivation – also called slash-and-burn cultivation, swidden, and (in India) jhum – has compromised native forest biodiversity. We explore this relationship with a case study from North East India where much of the remaining, intact, old tropical forest is found in the few protected areas and reserved forests (collectively PAs) of the region, and where jhum has largely permeated much of the rest of the landscape. Our analysis and mapping of land use and cover types, levels of forest fragmentation, and occurrence of jhum lands suggests that: buffer zones around PAs could contain additional, intact forest; incursion into PAs can reduce their effective interior core forest area; and forest wildlife habitat, particularly for Asian elephant, can be delineated among PAs in corridors consisting of low-fragmented, native forest cover. As human population density and concomitant anthropogenic stressors increase, however, more severe effects of increased rates of jhum on forest biodiversity will be felt. Offsetting such effects will entail not just redirecting jhum activities but also addressing the full cultural, social, economic, and even religious context in which shifting cultivation is pursued. Solutions must consider effects on nutrition, health, education, economic trade, and traditional lifestyles.