Forest ecosystems account for over two-thirds of net primary production on land–the conversion of solar energy into biomass through photosynthesis making them a key component of the global carbon cycle and climate (MEA, 2005). Forests are terrestrial units of living organisms (plants, animals and microorganisms), interacting among themselves and with the environment (soil, climate, water and light). The forests of the world harbor very large and complex biological species diversity and hence, it becomes a complex thing to assign a specific definition or explanation for it. The species diversity is an indicator for biological diversity and the species richness increases as we move from the poles to the equatorial region.

Forests in India are mainly tropical, sub-tropical, temperate, and alpine, which are further divided into 16 types: Tropical (wet evergreen, semi-evergreen, moist deciduous, littoral and swamp, dry deciduous, thorn, dry evergreen), Sub-tropical (broad leaved hill forests, pine, and dry evergreen), Temperate (montane wet, Himalayan moist temperate, Himalayan dry temperate), and Alpine (sub-alpine, moist alpine and dry alpine scrub). Among terrestrial biomes, the contribution of tropical forests is relatively higher to climate relevant cycles and biodiversity related processes. These forests constitute the earth’s major genetic reservoir and global water cycles.
Landscapes are viewed as a mosaic of forested, non-forested fragments of land that differ from area to area depending on climate, land use and history.  The forested landscapes are referred as a central midpoint of human development by means of its unique goods and services. The changes in these regions will cause an irreversible impact on human life. Forest has significant functions in producing timber, providing recreational places (Kindstrand et al., 2008), conserving  biodiversity (Li et al., 2009), restraining soil erosion (Nandy et al., 2011), regulating air humidity and temperature and managing global warming (Cabral et al., 2010).
Forests constitute the prime natural resources aiding in socioeconomic development and environmental protection for human’s livelihood.  Deforestation has been considered as principal driver of global warming and consequent changes in the climate. Alterations in forest structure through fragmentation of contiguous forests have influenced the functional abilities evident from the decline of water and carbon sequestration potential. Forest fragmentation is the consequence of simultaneous reduction of forest area, increase in forest edge, and the sub-division of large forest areas into smaller non-contiguous fragments.
The changes in forest structure are largely manifestations of the enhanced human induced activities like unscientific timber logging, encroachment of forest land for agriculture, intensified agriculture, forest fire and infrastructure development. A host of processes are related to the disruption of continuity in predominantly natural landscapes (Buskirk et al., 2000).  Forest fragmentation is well acknowledged as the replacement of huge areas of native forest ecosystem by other and leaving isolated forest patches. Qualitative and quantitative changes in forest ecosystems have been noticed due to the clearing of native forest for cultivation, harvesting, pasture, or unplanned urban development, etc. These transformations involve forest fragmentations dividing the continuous forest to smaller fragments with isolation of forest patches.
Fragmentation process involve complex dynamic interactions between the natural landscape and humans’ ever increasing demand for land creating a mosaic of natural patches to smaller tracts of forest surrounded by other land uses, causing a disruption in continuity of the natural landscape and ecological processes. The factors that are driven by the economic, the human activities, including land cultivating, over logging, mining, etc. have reduced the forest extent. Subsequent edge effects of fragmented forests extend into interior forest areas. Edge creation alters forest structure and composition in interior forest as well as the forest edge. The detrimental effects of forest fragmentation from deforestation will provide easier access to interior forest, leading to increased conversion to agriculture and exotic plantations (Ramachandra et al., 2010). The edge effect may even perish large trees within 300 m of the forest edge, which are replaced by densely spaced short-lived pioneers (Laurance et al., 2000), resulting in decreases in forest biomass and basal area (Harper et al., 2005). The negative impacts of edge effects on ecosystems include shifts in plant and animal community composition and changes in diversity (Cagnolo et al., 2006), seed dispersion, predation, fire susceptibility, altered microclimate, and increased carbon emissions (Laurance et al., 2002). Consequences of edge effects (Carolina 1995) are  abiotic effects-changes with environmental condition, biological effects-abundance and distribution of species and indirect effects-seed dispersal, pollination, alteration of micro climate.
Linear clearings for road, power line infrastructure increases substantially the edge length within forests. The widespread distributions of linear infrastructure within intact forest have the potential to substantially increase the spatial extent of disturbed areas by internal fragmentation (Marsh & Beckman, 2004). Canopy openings from logging disturbances are, however, far smaller than clearings for farms or estates which generally lead to increased wind speeds, desiccation, and other microclimatic alterations, which in turn are key drivers of edge effects (Laurance et al., 2002). The decline in the size of the forest and the increasing isolation between the two remnant patches of the forest has been the major cause of declining biodiversity.  Habitat for certain wide ranging species, such as large mammals and migrant birds, can be permanently destroyed. Edge environments create pathways for invasive species, domestic predators, and disease vectors. Apart from affecting the biodiversity and ecology of the region, forest fragmentation has a significant influence in the movement of soil (silt) and debris in an undulating terrain with high intensity rainfall. This will lead to landslides triggered due to unstable slopes with scanty vegetation cover (Ramachandra et al., 2012). Habitat fragmentation of high productive ecosystems due to human land use changes can strongly influence ecosystem goods and services including carbon sequestration and biodiversity conservation. The ecological variations that are occur at the boundaries of ecosystems, including discrepancies in the microclimate, influences from adjacent communities and land uses, and an altered species composition due to  greater amounts of edge habitat resulting from landscape fragmentation reduce habitat available to interior species. Fragmentation changes the distribution of market and non-market benefits and costs from the landscape. From an economic perspective, there are both winners and losers as a result of forest fragmentation.
The homogenization of the landscape (large extensions of the same species stands) creates an irreversible land use trajectory with major implications on biodiversity (Kanowski et al., 2005; Barlow et al., 2007; Niklitschek, 2007). The establishment  of plantations in the regions with native vegetation has  caused  significant  alterations in landscape  structure in both  tropical  and  temperate  areas  (Bremer & Farley, 2010; Lindenmayer, 2010). Removal of native vegetation to cater to the demand of forest based industries and afforestation of such regions with monoculture plantations has been the threat to natural forest ecosystem evident from the enhanced human – animal conflicts, lack of connectivity, reduced hydrological yield in the catchment, extinction of species, frequent instances of wild fire, etc. (Little et al., 2009). Planting native species will contribute to biodiversity when established in degraded lands rather than replacing natural ecosystems, such as forests, grasslands. Studies have substantiated the implications on biodiversity, water flows and human communal relations due to the large scale plantations in corporate landholdings (Gerber, 2011). Forest connectivity and hydrological regime in the catchment are equally dependent upon land-use, nature of vegetation, etc. Planting of exotic species of Eucalyptus in the natural montane grasslands of Nilgiris in India has led to the decline of water yield in the catchment by about 23% (Sikka et al., 2003) apart from the decline of biodiversity due to the disruption of food chain.
Accessibility and better connectivity with roads influence forest logging and deforestation. The market force driven by forest based industries push rapid expansion of plantations followed by removal of native vegetation (Diaz et al., 2011), which disrupts inter linked biodiversity of the region (Bremer & Farley, 2010). Accelerating rates of fragmentation in an ecologically fragile Western Ghats and creating increasingly complex environment would result in higher instances of human-animal conflicts and decline of food and water security. Understand of the connection of fragments with surrounding landscape elements is necessary to stabilise forest fragments, and their regeneration to their former natural structure. The drivers of forest fragmentation is outlined in Figure 1.1.

Figure 1.1: Landscape transition and its drivers

The deforestation (led by socio-economic processes), agriculture expansions, human induced forest fires are observed as main drivers in the region. Figure 1 illustrates transition of landscape and causal drivers. Forest fragmentations have led to changes in the structure and composition of forest ecosystem. Edges will become more prominent due to disturbances leading to higher light availability and loss of soil moisture. This will directly impact seed dispersal, regeneration of native species, spread of invasive species, weeds, etc. The changes in forest structure and composition make fragments prone to fire. These disturbances will ultimately disturb the natural ecosystem productivity resulting in reduced goods and services.
1.1 Quantification of forest fragmentation:
Land use patterns have important environmental and social consequences. Land use (LU) modifications driven by anthropogenic activities alter the structure of the landscape and influences the functioning of an ecosystem. This change is prominent and need to be measured at temporal scale which helps in monitoring the ecosystems and implementation of location specific mitigation measures. Availability of spatial data acquired remotely through space-borne sensors since 1970’s  help in the quantification of land use dynamics. Satellite remote sensing technology provide consistent measurements of landscape condition, allowing detection of both abrupt changes and slow trends over time for managing natural resources.  The temporal dynamics of forest landscapes helps in assessing the implications of human activities on the ecological process. Changes in forested landscapes of Western Ghats have been more sudden since the middle of the last century due to policy impetus to industrialisation, urbanization and globalization.
Fragmentation refers to the breaking of an ecosystem or habitat or land use type into small parcels of land inducing isolation. This transformation is driven by the human activities causing explicit changes in the landscape. It has effect in terms of patch size and shape, connectivity and causes changes in internal heterogeneity, thereby restricting the movement of species. It also create barrier to the normal route of species and thus limiting the potential of species for dispersal and colonization.
Fragmentation will result in spatial pattern changes making forests vulnerable with an increase in the number of patches, patch shape complexity and isolation. Determinants of fragmentation disturbance pattern are mainly spatial (size of area disturbed), temporal (period of disturbance) and severity. Fragmentation analyses provide insights to the configuration of individual landscape elements, e.g. the shape of individual patches, and characterises land-use changes impact on habitat topology and configuration.  Spatial data acquired remotely through sensors mounted in satellite platform at regular intervals helps in assessing the temporal changes with spatial patterns. Geoinformatics is very effective in assessing the issues of ecological concern driven by changes in land uses with forest loss and fragmentation. Remote sensing data with geographic information systems (GIS) have made significant contribution to examine the pattern and process of forest ecosystem (Nandy et al., 2011; Ramachandra et al., 2011). Remote sensing data provides spatial information for quantitatively estimating biophysical characteristics of forest areas  as well as modeling long term forest landscape development and process at a relatively large spatial scale. The availability of remote sensing data with improvements in resolutions, enable the creation of land cover maps and with the innovative analytical techniques, helps to monitor and analyze forest fragmentation at a timely and cost-effective way.
Geographic information system (GIS) with temporal spatial information assist in the criteria-based decision making, in the selection of the best alternative considering spatial aspects based on a series of conflicting objectives. The advancement in remote sensing data with improvements in spatial, spectral and temporal resolutions has improved the capability for detecting significant changes in the landscapes, as well as potential precursors to future changes. This is possible by combining continuous and discrete analyses, within-class variation occurring in landscapes, captured by the true dynamism and variability of the social-ecological processes. This aids in the comprehensive assessment of the impacts of forest fragmentation and appropriate mitigation measures to conserve biodiversity.