M Sc Dissertation(WII)

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Impact of Habitat Fragmentation on Diurnal Squirrels in Lowland Tropical Forests of Upper Assam North-East India
(Wildlife Institute of India, Dehradun, 2019) Sumashini, P.S.; Nair, Manoj V.; Qureshi, Qamar
The effect of forest fragmentation on a set of ecological parameters, namely, species richness, densities, activity patterns, vertical space use for foraging, diet and nesting characteristics of diurnal tropical tree squirrels was investigated in five forest fragments (three in <5 km2 and two in 20-30 km2 size classes) and compared against two large forest tracts (>100 km2) in upper Assam, north-east India. The study focused on the four common diurnal squirrels, Malayan Giant Squirrel, Red-bellied Squirrel, Hoary bellied Squirrel and Himalayan Striped Squirrel. A set of established trails were used to survey the sites. The diversity of squirrels in the fragments was explained by size of the fragments, intactness of the forest and disturbance levels. The fragments were in a state of continuous degradation, habitat variables being influenced more by disturbance levels than by size. Medium-sized fragments continue to retain the diversity of squirrels by the virtue of small pockets of intact habitat in the fragments, while small fragments have been rendered depauperate by synergistic effects of habitat loss, degradation and hunting. Density estimation using trails as transects under distance sampling framework revealed that densities of Malayan Giant Squirrel showed a declining trend in medium fragments and the absence of the species in the small fragments. Densities of Himalayan Striped Squirrel were comparable in large forests and medium fragments and the species was not recorded from the small fragments. Densities of RBS were high across all sites, including the small fragments Time activity budget, vertical space use for foraging and diet were investigated underthe umbrella of changes along basic niche dimensions of time, space and diet. Niche width along time decreased in the fragments for all squirrels suggesting reduced active periods. For the Malayan Giant Squirrel, niche width decreased along the other two dimensions as well in the fragments, suggesting restriction of foraging strata and diet. On the other hand, for the Red-bellied Squirrel, niche width increased along vertical space use and diet axes suggesting expansion of niche in the fragments. These differential responses of species to habitat fragmentation resulted in changes in overlap between species in fragments and a potential alteration of competitive dynamics between species in modified habitat conditions. Comparing trends in density estimates and responses of squirrels along basic niche dimensions revealed that similar inferences can be drawn from the two assessments about the potential sensitivity of a species to habitat fragmentation. Responses along basic niche dimensions can be possibly used to make prior assessments of responses to habitat alteration before differences in densities, which is a more gradual process, start to show up. It is clear from the findings of the study that diversity of squirrels depends on quality of habitat. Medium-sized fragments have the potential to retain the diversity of squirrels. They should be prioritized and accorded enough protection to deter further degradation and hunting in these fragments. Malayan Giant Squirrel and Himalayan Striped Squirrel appear to be sensitive to habitat fragmentation, while the Red-bellied Squirrel appears to be tolerant.
Floristic Composition and Patterns of Regeneration of Rainforest Trees in the Fragmented Forests of the Anamalai Hills, Southern Western Ghats
(Wildlife Institute of India, Dehradun, 2003) Balasubramaniam, Priya; Qureshi, Qamar; Chellam, Ravi
The word diverse is almost a synonym for tropical rainforests. In no other habitat are found such an enormous number of life forms. These highly diverse systems are now facing severe threats as a result of habitat fragmentation. The aim of this study was to study the floristic composition and patterns of regeneration in the fragmented forests of the Anamalai hills, southern Western Ghats.Six fragments were chosen which varied in size and disturbance levels. They were- Iyerpadi (>2600ha), Andiparai (>185ha), Puduthotam (92ha), Pannimedu (66ha), Varattuparai 1c (11ha) and Varattuparai 4 (4ha). Quadrats of · 3 sizes were used to sample for different variables. 20 x 20m quadrats were used to enumerate tree sp, 5 x 5m quadrats were used to enumerate sapling sp and 1 x 1 m quadrats were used to count the numbers of seedlings. Height (m), GBH (cm), lopping I cutting signs, altitude, canopy cover, presence of weedy shrubs and ground cover of weedy herbs were the other variables measured. A total of 112 quadrats were laid, 25 in the first 4 fragments, 9 and 3 in the last two respectively. The findings revealed that tree and sapling generic richness showed a negative relationship with disturbance and time since isolation. Their correlations with area though positive were weak. Fragments were subjected to varied nature and levels of disturbance. Fragment characteristics such as area, time since isolation did influence the patterns of tree and sapling composition though weakly. There is an extremely weak correspondence between the tree and sapling composition of each fragment. There was a high number ' of non rainforest species in fragments which were relatively more disturbed. Relatively undisturbed fragments were more rich in rainforest trees · and saplings. Fragments showing higher levels of canopy openness were relatively more disturbed than others. Disturbed fragments also showed higher levels of weed invasion. Iyerpadi showed the highest generic richness in trees and saplings. Varattuparai 4 showed the least richness in both trees and sapling. Human disturbance due to its chronic. nature was the principal predictor of both tree and sapling composition.

M Sc Dissertation(WII)

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