Theses and Dissertations
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Item Diurnal and Seasonal Activity Pattern of Water Monitor (Varanus salvator) in Bhitakanika Wildlife Sanctuary, India(Wildlife Institute of India, Dehradun, 1993) Pandav, Bivash; Choudhury, B.C.This study investigated the diurnal and seasonal activity pattern of water monitor, Varanus salvator in Bhitarkanika Wildlife Sanctuary, India. The study was conducted in an intensive study area of 17 sq.km selected after a pre sampling survey in the Sanctuary. The methodology involved to record the activity pattern of water monitor was monitoring of two permanent standard paths every three hours on diurnal basis. Sightings of water monitors were recorded while walking on the standard path. Behaviour of water monitor was divided into four categories such as basking, foraging, resting and non-foraging. Microhabitat of water monitor was recorded on each sighting. Ambient and substrate temperatures and ambient relative humidity were recorded along with diurnal activity pattern of water monitors. Results show a shift in diurnal activity pattern with season. The activity pattern of water monitor was unimodal in winter and uniform in summer. Basking was the major activity of water monitor in winter, whereas all the activities were evenly spread out in summer.The lizards used different microhabitats for different activities. Maximum lizards were recorded active at cooler substrate temperatures (29°C). The relation of ambient and substrate temperatures with activity was curvilinear. At low ambient temperature basking was prevalent. With increase in temperature other activities, such as foraging and resting were recorded. At high ambient temperature lizards selected cooler substrates. Ambient temperature and ambient relative humidity varied inversely. The activity was low at high levels of humidity It is concluded that behavioural thermoregulation plays a major role in water monitor’s activity.Item Effect of Habitat Alteration On Herpetofaunal Assemblages on Evergreen Forest in Mizoram, North-East India(Wildlife Institute of India, Dehradun, 1999) Choudhury, B.C.; Panwar, Samraat; Rawat, G.S.The response of frogs and Lizards to habitat alteration was studied in South Mizoram. Chronoseres were selected such that two successional gradient were represented- jhum fallows regenerating to mature forest. and jhum allows converted to teak plantations. Herpetofauna were sampled by three techniques- strip transects, pitfall trapping. and systematic searching. Species richness of herpetofauna increased along the jhum-mature forest gradient. However. teak plantation had a depauperate herpetofauna. similar in composition to the 1- year jhul1l fallows. All frogs and lizards were c1assilied into 6 guilds on the basis of their activity period (diurnal or nocturnal) along with whether they were terrestrial , arboreoterrestrial or arboreal. Analysis of the strip-transect data showed that there were distinct differences in the distribution and abundance patterns of diurnal and nocturnal species. To examine patterns, multidimensional scaling (MDS) was used for indirect gradient analysis in two ways- firstly to summarize differences between sites and secondly, to explore possible associations between herpetofaunal guilds and habitat parameters across categories. The MDS differentiated two different groups of habitat variables. One group makes up the gross structural components of the habitats. while the other represents microhabitat parameters. All guilds were more strongly associated with trends in microhabitat distribution. than macrohabitat-parameters. while species richness showed diffuse associations with habitat parameters. The assemblages in the I to 10 yr. jhum fallows and teak plantations were dominated by a set of terrestrial and arboreo-terrestrial lizard species. Most of those species are distributed widely. either in the Indian subcontinent. or further east and south. into South-east Asia. On the other hand. a number of frogs and some lizards were restricted to mature forest. Most of these species are restricted either to North-east India. or to the study area itself. and some are apparently hitherto undescribed species. The fact that so many narrowly distributed species were found in mature forest has obvious conservation implications. Overall. the results suggest that in a mosaic of habitats resulting from jhum-cultivation. even remnants of primary forest may be of immense importance for persistence and recolonization by mature forest herpetofauna. Teak plantations offer a very marginal habitat for a large set of herpetofauna. even after a long period of growth.Item Pollinator Visitation and Reproductive Success in Two Species of Mangrove Plants, in Bhitarkanika Wildlife Sanctuary, Orissa(Wildlife Institute of India, Dehradun, 1997) Pandit, Shalini; Choudhury, B.C.Visitation patterns to the flowers of Sonneratia caseolaris and Aegiceras corniculatum were investigated between December 1996 and April 1997, in the mangrove forests of Bhitarkanika Wildlife Sanctuary, Orissa. The objectives of the study were to determine the pollination effectiveness of the different categories of visitors by quantifying their rate of visitation. The effect of environmental variables on visitation was examined, and the importance of the visitors to the reproductive success of the plant was investigated by conducting exclusion experiments (Le. bagging flowers to prevent visitation). Nectar was analysed for volume and sucrose content in S. caseolaris, and the impact of predation on the reproductive success of the plant was examined. The results of the study indicated that the flowers of both plant species attracted a wide array of visitors and did not show a specialised relationship with anyone visitor species/category. Different categories of visitors were seen to vary in their pollination effectiveness for the two plant species. Environmental variables such as temperature, sun intensity and wind velocity were seen to influence the visitation of Lepidoptera to the greatest extent, and Hymenoptera to a lesser extent. Visitation by birds was found to be independent of the environmental variables. The territorial behaviour of purple-rumped sunbirds at the S. caseolaris site was seen to reduce visitation of other birds and of bees to the flowers of this species. Results of the bagging set-ups indicated that there was no difference in the pollinator effectiveness of the nocturnal and diurnal visitors. Reproductive success was not pollinator-limited in either of the two plant species.Item The Diel Activity Pattern of Indian Python (Python molurus molurus linn) at Keoladeo National Park and Some Factors Influencing it(Wildlife Institute of India, Dehradun, 1991) Bhatt, Karamvir; Choudhury, B.C.This study investigated die] activity pattern of Indian python (Python moJurus molurus Linn) at Keoladeo National Park Bharatpur. The study was conducted in an intensive study area of 0.5 Sq Km selected after pre sampling survey in the park. The methodology involved to estimate activity pattern of pythons was monitoring of a permanent transect every four hours, on diel basis, to record python’s tracks and sightings. The diel variations in temperature, humidity, burrow microclimate, prey activity and prey abundance were also quantified along with diel activity pattern of python. Results show a shift in diel activity pattern with seasons. The activity pattern of pythons was diurnal in winter, uniform throughout spring and bimodal crepuscular in summer. There was no significant correlation between python activity and other factors quantified, though temperature and humidity affected the diel activity pattern considerably. The microclimate variation gradient existing between outside and inside burrow possibly play an important role in occupation of the burrow and this in time influence the surface diel activity pattern. The shift in the diel activity is attributed to seasonal change in the abiotic factors. No relationship between prey abundance and activity pattern could be established possibly because python’s ability to go with out food during the cool season. Other factors not quantified during this study like reproductive behavior, body size and biotic disturbances are suspected to be responsible for the observed diel activity pattern of pythons. It is concluded that the diel activity pattern of pythons in KNP is not influenced by just one factor but is a manifestation of a combination of various abiotic, biotic and endogenous factors. A temperature sensitive telemetry study would help further in investigating the ecological aspects of this cryptic species.