M Sc Dissertation(WII)

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Subject: search.filters.subject.Western ghats

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    Richness and Compositional Responses of Ants to Land use Change
    (Wildlife Institute of India, Dehradun, 2021) Shakur, Mohammad Abdau; Talukdar, Gautam
    Human-made changes to the ecosystem are leading to the loss of biodiversity across the world. Western Ghats (WG) known for its rich biodiversity has historically undergone fragmentation and loss of its primary forest cover which has significant negative effects on biodiversity. Studies have shown that fragmentation almost invariably leads to a decrease in species richness, a pattern consistently observed across different taxonomic groups. Ants, one of the numerically dominant groups in forest ecosystems, play a vital role in many ecosystem processes and yet is one of the least studies groups within the WG landscape. The effect of land use change on ants in forests, fragments, native shaded coffee plantations and silver oak shaded coffee plantations was studied in the Kodagu district of Karnataka, India. We hypothesized that habitat heterogeneity would decrease from forests to fragments to native shaded coffee plantations and silver oak shaded coffee plantations and this would consequently lead to a decline in the richness and change in species composition of ants along this gradient. To test this prediction, ants were sampled along transects in the four-land use types using both pitfall traps and modified wrinkler extractors. As expected, there is a reduction in structural complexity across forest, fragments, native shade coffee and silver shade coffee plantations. We found that at the level of a transect, species richness reduced from forests to coffee plantations. Interestingly, the trend reversed when viewed at the scale of the land use, where all the forest sites together were the least species rich while the coffee plantations collectively showed the highest species richness. With respect to species composition, we found that coffee plantations had species adapted to drier environments whereas species inhabiting leaf litter were primarily found in forests and fragments. Coffee plantations with human residence inside had higher species compared to those not inhabiting. This study highlights the importance of scale for assessing the biodiversity potential of human modified habitats and for assessing their conservation potential.
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    Montane Lizard in a Mosaic Landscape: Effect of Tea Plantations on Anamalai Spiny Lizard (Sales anamallayana)
    (Wildlife Institute of India, Dehradun, 2021) Devrajan, Anjitha; Ramesh, C.; Das, Abhijit
    The Anamalai Spiny Lizard (Salea anamallayana), an agamid lizard endemic to southern Western Ghats is reported to use shola and tea plantations of Kannan Devan hills of high ranges of Kerala. The Western Ghats has experienced extensive habitat destruction and modification since a very long time and the lizards are highly affected by habitat modification which in turn affect their fitness and survival. In this study we investigated the effect of habitat modification on morphology, population and habitat association in Salea anamallayana in the shola forests of Eravikulam National Park and surrounding tea plantations. The study was conducted from February 2021 to May 2021. Line transect method was used to study density and Visual encounter surveys for collecting data for basking habitat use and morphology. Surveys were conducted from 9 am to 2 pm since the lizard was more active during the time period. Shola and plantation are structurally very different. Shola was divided into shola close to plantations and shola away from plantation. Plantation was classified according to the proximity to shola and presence of shade trees. The density was found to be more in shola (27.59±6.79/ha) compared to plantation (8.63 ±2.21/ha). In plantations, the density was influenced by proximity to shola and presence of shade trees. Density is more in plantations in close proximity to shola (20.91±4.51/ha) compared to plantations away from shola (2.85±1.37/ha) and the lizard was present only where the shade trees were planted. The sex ratio was biased towards male in plantations (100:14) and it improves in shola close to plantations (100:33) and further improves in shola away from plantations (100:50). The body condition of male lizards was poor in plantations compared to shola away from plantations (t = 2.57, df = 14.17, p-value = 0.021). The males do not differ in other morphological variables across the habitats. Body condition of males is better than females (t = -2.19, df = 23.80, p-value = 0.037). The basking habitat use is in proportion to habitat availability. The microhabitat use varies across shola and plantation. Average perch height and perch diameter is more in plantation and average canopy cover is more in shola. More diverse perch surface is available and used in shola compared to plantation. The average body temperature is high in plantation compared to shola and the body temperature is directly proportional to atmospheric temperature and substrate temperature. There is no significant difference in Flight Initiation Distance (FID) between shola and plantation. FID is inversely correlated to substrate temperature.
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    Influence of Forest Cover on Fruit and Frugivore Richness and Abundance in Southern Western Ghats
    (Wildlife Institute of India, Dehradun, 2021) Takorbhai, Patel Zankhnaben; Page, Navendu V.; Kumar, Amit
    Habitat fragmentation is a pervasive threat to ecosystem processes like seed dispersal, which is vital for biodiversity maintenance in tropical forests. Habitat fragmentation negatively impacts the richness, abundance and composition of plants and animals, thereby disrupting the interactions between them, with cascading impacts on biodiversity. However, the remnant fragments continue to harbour biodiversity. However, it is critical to determine the functional value of the fragments in terms of fruit resource diversity and availability and prevalence of frugivores across different size classes. To this end, I conducted the study in the Valparai plateau and adjacent contiguous patches of rainforests in the Western Ghats. I first determined the organization of plant-seed disperser community and identified key frugivores and plants in the landscape using network analysis. Using mixed models and the recently developed Joint Species Distribution Modelling approach called HMSC (hierarchical modelling of species communities), I investigated 1) the relationship between the amount of forest cover and richness of fruiting plants across different seed size classes, 2) the relationship between the amount of forest cover and availability of fruit s across different seed size classes 3) the relationship between richness and presence of all the avian frugivores and, amount of forest cover, and richness and availability of fruits. I recorded the frugivores and fruiting plants from 33 trails distributed in 12 fragments and 2 sites in contiguous area during four months of sampling. I also recorded plant-frugivore interactions. I documented 49 species of fruiting plants and 17 species of avian frugivores
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    Responses of Raninforest Lizard Communities to Tea Plantation Edges in the Anamalai Hills of Southern Western Ghats India
    (Wildlife Institute of India, Dehradun, 2013) Malgaonkar, Aditya, S.; Habib, Bilal; Vasudevan, Karthikeyan
    Human-made edges are an omnipresent form of altered habitats across the entire Western Ghats landscape. Furthermore a diverse range of edge types exist differing in the structure and composition of their altered surrounding habitat. Only a few attempts have been made to study the influence of the structure of this adjoining habitat or the 'matrix' on edge effects. Understanding the influence of different matrix habitats on edges will lead to the better understanding of the abiotic and biotic influences of the matrix on forest edges. Vegetation structure and composition has been the subject of several studies pertaining to fragmentation as well as effects of edges and both primary as well as secondary responses to edge effects have been documented. It has also been noted that while the reduction in plant species richness may occur as a result of decreasing forest area, it is more likely that this could be the result of increasing perimeter to area ratio resulting from fragmentation and increased proportion of area exposed to edge effects. The abiotic as well as biotic changes which affect vegetation not only bring about structural changes such as those in canopy cover, vertical stratification, density etc, but also affect functional aspects of plant communities such as pollination, seed dispersal and germination. Faunal communities respond in various ways to changes in their habitat; these may include changes in abundance, species richness, structure and composition of communities as well as behaviour of individual species. With respect to edge effect these changes or may vary in their magnitude and the distance or depth to which they penetrate into the interior. Magnitude and depth of influence are two complementary but distinct aspects of edge effects. Magnitl1de of influence is the degree to which a response value (a biotic or abiotic variable used to measure edge effects) differs between the edge and the interior while depth of influence if the maximum distance to which edge effects percolate into a habitat. However. A large amount of research on this topic has been restricted to birds and mammals and the responses shown by them might not be representative of the responses of other lesser known taxa.
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    Factors Influencing Movement Pattern Habitat Use and Distribution of King Cobra (Ophiophagus hannah)- A Multiscale Approach
    (Wildlife Institute of India, Dehradun, 2011) Rao, Chetan S.; Talukdar, G.; Choudhury, B.C.
    The king cobra (Ophiophagus hannah) is the largest species of venomous snake in the world. It is a widely distributed species occurring in India and Southeast Asia. Most of the habitat use studies of ophidians are responses of ambient temperature. These results are often correlated with temperate areas where there is a significant shift in temperature annually. In tropical ecosystems, to understand ecology of a large bodied species like the king cobra would be interesting, knowing the fact that very little work has been done so far. The objective of my study was to procure relationship of ecographic variables on movement pattern, habitat use and distribution of king cobras at an individual and at a population level. This study was carried out in Agumbe, Karnataka in the Western Ghats region of India for 4 months during December 20 I 0 to April 2011 . Habitat utilization points were sampled throughout the study area, which basically was placed within the boundaries of a 2x2 sq.km grid enclosing all the presence locations collected during five years from the ongoing King Cobra Telemetry Project conducted by the Agumbe Rainforest Research Station and the University of Arizona in collaboration with the Karnataka state forest department. Retreat sites (n=262) were selected where the tagged (n=5) had been recorded and sampled for microhabitat variables. Nest sites (n=13) were also looked into, to explore site selection by females. A total of 30 ad libitum sightings of king cobras were recorded during the study. Prey density walk was carried out to derive a relative abundance based on encounter rate in the study area that came to be 1.24 animals/km. A total of 9 species of prey were encountered during prey density walks. The kernel estimates and minimum convex polygon for four radio tagged individuals was calculated for home ranges and area vs. availability was computed for habitat preference and use using Jacob's (1974) Index. The results of this study show a strong correlation of ambient temperature of range 20- 35°C (Beta coefficients 7.7eI0-l ± 0.0545) and relative humidity (70-90%) (Beta 15 coefficients 1.25 ± 1.14) with movement pattern and habitat site selection and also affect distribution patterns of this particular king cobra sub population. It is also found that king cobras do not particularly obligate themselves to a particular habitat type except for some degree of preference towards evergreen forest. The microhabitat however, influencing king cobra movement and habitat use are fallen logs on the forest floor (Beta coefficients 2.327e+00 ± 5.113e-Ol) and dead vegetation on the forest floor (Beta coefficients 2.042e-02 ± 6.796e-03) which have a stronger correlation with presence while ground burrows show a negative correlation. Leaf Litter Depth in the forest floor in sites with range of 4-7 inches deep (Beta coefficients 0.64269 ± 0.30998) influences nest site selection. Using secondary rescue data of five years and all the other presence records for king cobras in the wild, I ran a MaxEnt presence only model (auto model) using only environmental variables taken from BIOCLIM to test environmental parameters influencing distribution. The places of higher precipitation within the study area indicate a higher influence on occurrence and places of higher temperature and aridity regimes does not indicate occurrence of king cobras. The management recommendations for conserving such large bodied snakes would be a multidimensional approach. The local people within the study area do not kill king cobras, due to religious reasons. However, these attitudes are changing and so also some of the tolerant ideologies of the local people. King cobras have been found to occur more in a landscape matrix dominated by evergreen forests and decline in evergreen forest due to land use conversion could be the emerging possible threats to king cobra in the Western Ghats.
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    Patterns in plant species richness and diversity in the forest fragments of Western Ghats, Karnataka.
    (Wildlife Institute of India, Dehradun, 2007) Page, Navendu V.; Qureshi, Qamar; Rawat, G.S.
    Patterns of species richness diversity and distribution, and the factors affecting these patterns have always attracted the attention of many ecologists. Degree of fragmentation is one such factor affecting the species richness and composition also of great importance to conservation biology in light of rapid loss of biodiversity. The study examined the patterns of distribution and species richness and its correlates in a fragmented landscape in Kodagu district, Western Ghats, Karnataka. The study also examined some of the factors affecting distribution of epiphytes such as distribution along the tree height gradient and host specificity. A total of 129 species of trees, 29 species of Iians as and 68 species of vascular epiphytes were recorded in 56, 25m x 25m square plots. 60 species of shrubs were recorded in 90, 5m x 5m square plots. Patch area was found to be significantly correlated with tree species richness, but area was not correlated with shrub, liana and epiphyte species richness. However plant density used as measure of site specific productivity along with area were significantly correlated with lianas and epiphyte richness. Neither of these could explain the variation in shrub species richness. Lianas and shrubs did not show any such trend but epiphyte richness showed a negative trend in rarefied species richness with increase in area. Rank abundance curves indicated that Reserve forest had the most equitable distribution of abundance classes and also more number of rare species. Species composition was found to differ significantly across different size classes. All the plant communities showed moderate levels of nestedness. Distribution of an epiphyte along the tree was not influenced by the mode of dispersal alone. There was no strong evidence in support of host specificity however some selective host species were found to be favoured by epiphytes.
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    Impact of Teak Plantations on Forest Butterfly Communities in Parambikulam, Southern Western Ghats, Kerala
    (Wildlife Institute of India, Dehradun, 1997) Nair, Manoj V. ; Johnsingh, A.J.T.
    Butterfly communities in natural and man modified habitats were studied at Parambikulam Wildlife Sanctuary, Kerala from December 1996 to April 1997 to understand the impact of a long history of habitat conversion on forest butterfly communities. Community attributes were investigated in evergreen and moist deciduous forests (EGF and MOP respectively ,together comprising natural habitats) and a gradient of teak plantations {TKPs} of different ages (14.3tJ,54 and 74 year old TKPs, together comprising altered habitats).