Introduction

The Western Ghats bioregion is rich with flora and fauna and is considered as one among the 36 biodiversity hotspots (also one among the eight hottest hotspots of biodiversity) of the world (http://www.conservation.org). The region with a wide range of forest types ranging from tropical wet evergreen forests to grasslands is a repository of rich flora and fauna (Daniels, 2003; Sreekantha et al., 2007; Gururaja, 2004) evident from the occurrence of over 4,000 species of flowering plants (38% endemics), 330 butterflies (11%

endemics), 156 reptiles (62% endemics), 508 birds (4% endemics), 120

mammals (12% endemics), 289fishes (41% endemics) and 135 amphibians (75% endemics). The forests of Western Ghats, in view of their floristic diversity and numerous multipurpose species, areconsidered a repository of economically important plants. Due to unplanned developmental activities, large blocks of contiguous native forests are being reduced to remnant patches of secondary habitats, affecting the ecology, hydrology and biodiversity. The impacts of these human induced changes are evident from extinction of species and increased population of exotic/invasive species (Daniels, 2003). Vast stretches of barren lands, barren hill tops, reduced water infiltration and water retention capability of the catchment has led to the conversion of perennial streams to intermittent streams and lowering of water table. Implications of the changes in ecosystem structure, function, and distribution, due to global climatic changes and land-use practices have

raised serious concerns and also brought a paradigm shift in the approach towards ecosystem from human versus ecosystem to human and ecosystem along with the concept of 'sustainable development' in conservation and management of natural resources. Last few decades, have seen increased awareness on the need for conservation and sustainable use of the natural resources of Western Ghats (Chandran, 1998). Ban on timber extraction in 1988 from natural forests has kindled the hope of biological revival of the Western Ghats forests.

Landscape dynamics

Landscape refers to the heterogeneous land features composed of sets of interacting ecosystems and is characterized essentially by its dynamics that are partly governed by human activities (Ramachandra et al., 2012). Human induced land cover and land use changes are considered as one of the pervasive sources of alteration on Earth's surface (Houet and Verburg, 2010). Consequences of land use changes such as forest fragmentation poses a serious threat to the ecological sustainability of a landscape (Ramachandra and Uttam Kumar, 2011).

Forest fragmentation is a process of isolation of forest patches which results in change of composition, structure, extent and spatial patterns through human induced activities (Roy et al., 2002). Fragmentation implies division of landscape into smaller parts which results in uneven separation, size and dis-connectivity between population and similar ecosystems (Forman, 1995; Griffiths et al., 2000). Fragmentations of landscape have been quantified by changes in spatial characteristics and configuration of remaining patches (Saunders et al., 1987). Various ecological effects of forest fragmentations are loss of species populations, increased isolation of remnant populations, inbreeding (Laurance et al., 1998; Boyle, 2001), enhanced

human-animal conflicts, decline in ecosystem goods and services, etc. This necessitates understanding of the causes of forest and habitat fragmentations , in order to evolve effective management strategies for conservation.

Remote sensing (RS) data acquired through space borne sensors available since ?O's at regular intervals can be used as one of the major tools to understand LULC dynamics and quantify the extent of forest fragmentation (Gustafson, 1998; Turner and Gardner, 1991; Jha et al., 2005). Land use details derived from temporal RS data offer potential for assessing the changes in land uses, forest fragmentation and its impact on ecology and biodiversity (Ramachandra et al., 2009). Categorization and understanding of forest fragmentation using spatial data (RS data) provides a picture of the degree and extent of fragmentation, which are useful for conservation of the affected habitat fragments (O'Neill et al., 1997). Numerous measures of forest fragmentation and forest

connectivity using spatial data include average forest patch size, mean forest patch density, number of forest patches, forest patchiness, forest continuity, and proportion of forest in the largest forest patch (Vogelmann, 1995; Wickham et al., 1 999).

Quantification of Pf and Pff has effectively helped in assessing the process of fragmentation (Ramachandra et al., 2009). This communication assesses the LULC dynamics in Chikkamagalur and examines the extent of forest fragmentation in Chikkamagalur landscape . The objectives of current study are:

1. To assess the present status of forests of Chikkamagalur;
2. Land use and land cover [LULC] dynamics in the district considering temporal remote sensing data; and
3. Assessment of the extent of fragmentation of forests and its impact on the ecosystem