Landscape fragmentation & biodiversity conservation P. S. Roy and P. K. Joshi Indian Institute of Remote Sensing (NRSA) 4, Kalidas Road, Dehradun psr@iirs.gov.in and joshi@iirs.gov.in Abstract Human interventions in the Tropical ecosystem and resultant loss of biodiversity have raised concern among conservationists in the recent past. The loss in biodiversity has been attributed to habitat loss and fragmentation of the natural landscapes. Fragmentation generally results in the remnant areas of native vegetation surrounded by a matrix of agricultural or other developed land. There in turn has important influence on the biota within the remnant patches, especially at the areas at or near the edge between the patches and the surrounding matrix. These consequences vary with the distance from the patches and connectivity with the other patches. The physical distances and influences modify the size, shape and the position in the patch and its constituents. To research and manage these characteristics of the patch the spatial and temporal understanding of the landscape is required. The present paper focuses on the fragmentation of the natural landscape of Himalayas and biodiversity conservation. The satellite remote sensing in conjunction with geospatial modeling (GIS + GPS technology) provide a platform for landscape characterisation. This paper presents the landscape approach for characterising the complexity of landscape boundaries by remote sensing in the North East India. Land use change, Landscape dynamics and Landscape characterisation has been observed from patch to regional level. Landscape analysis showed that the indices of shape, richness and diversity provided an additional evaluation of land cover spatial distribution within the complex mountain landscape. The landscape analysis has provided an outline of the degree of propagation of the disturbance from the non-biotic sources and fragmentation. It is revealed that fragmentation has caused loss of connectivity, ecotones, corridors and the meta population structure. Introduction Initially Natural Ecosystems and their functioning should be guiding factor for human activities in the biosphere. However, overriding priorities and the human activities modify the landscapes to suit their own needs. Within the tropical regions, examples of intensive human land uses include agriculture, industrial and settlement. These land uses dramatically alter the ecological character of the land where they occur, and they tend to be permanent modifications at ecological time scales. The impact of any land use activity depends on (1) the degree of habitat modification and (2) the spatial extent and pattern of habitat modification. Spatial organisation of the landscape connectivity is important for sustained ecological functioning. Connectivity can exert strong influences on ecological processes such as the movement and dispersal of organism (Gardner et al., 1989), the use of resources by animals i.e. corridors (O’Nell et al., 1988), gene flow (Gilpin and Soule, 1986), and spread of disturbance. Changing the landscape patterns through fragmentation can disrupt ecological processes that depend on movement within the landscape. Disturbance is a very common and wide spread phenomenon in nature and may be defined as a discrete event along time that modifies landscapes, ecosystems, community and population structure, changing the substrate, the physical environment and availability of resources (White and picket, 1985). It can be considered as a basic process responsible for many other processes, such as fragmentation, migration, local and regional extinction etc. Disturbance and fragmentation are two related processes with strong relationships and it is difficult to distinguish the role and rate of the interactions. Disturbance is driven by many factors and interacts with other processes acting in a more restricted context, such as fragmentation. Fragmentation has a strong influence on the dynamics and fate of material and energy moving across a landscape. The disturbance regimes can be measured by using different indices i.e., degree of fragmentation, fractal dimension, contagion, juxtaposition, evenness and patchiness (Li and Reynolds, 1994). Attempts have been made to develop disturbance indices in the landscape (Anon., 2001).  Fig. 1: Land Use change in Sonitpur (Assam) (Anon. 2001)
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