Literaturdatenbank
Literaturdatenbank |
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Deepak, V. (2011). Ecology and behaviour of travancore tortoise (indotestudo travancorica) in anamalai hills, western ghats. Unpublished thesis , Saurashtra University, Rajkot, Gujarat.
Added by: Admin (06 Jan 2014 18:22:44 UTC) |
| Resource type: Thesis/Dissertation BibTeX citation key: anon2011d View all bibliographic details  |
Categories: General Keywords: Habitat - habitat, Indotestudo elongata, Indotestudo travancorica, Schildkröten - turtles + tortoises, Südasien - Southern Asia, Testudinidae Creators: Deepak Publisher: Saurashtra University (Rajkot, Gujarat) |
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| Abstract |
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Testudinidae Tortoises belonging to the genus Indotestudo are medium sized (330 mm) tortoises, found in the tropical forests of Asia and South East Asia. Out of the three known species of Indotestudo two (Indotestudo elongata & I.travancorica) are known from India. Travancore tortoise (I. travancorica, Boulenger, 1907) is an endemic tortoise found in Western Ghats of southern India. They inhabit diverse habitats in the moist tropical forests of Western Ghats. The current state of knowledge on the species ecological requirements and population estimates are lacking to suggest any conservation measures. To supplement the existing knowledge on the species this PhD study was carried out. Based on previous knowledge on the tortoise distribution, the study was decided to be carried out in two protected areas namely the Anamalai Tiger Reserve and Parambikulam Tiger Reserve. Located in the southern Western Ghats between 10o13- 10o33' North latitude and 76o37'-77o21' East longitude. This study investigated the proportion of the site occupied by Travancore tortoises, their diet, home range, activity and habitat use. The findings of this study along with the existing information were used to formulate a conservation action plan for Travancore tortoise. Populations of Travancore tortoises were monitored during the monsoon and post monsoon months during 2006 – 2009, twenty five trails located in four different habitat types were surveyed. Occupancy was modelled as a function of anthropogenic disturbance levels and environmental variables. Detection probability was modelled as a function of year, effort and environmental variables. Occupancy of Travancore tortoise was negatively influenced by anthropogenic disturbance level. Detection probability was positively influenced in sites with more number of water bodies and longer extent of grass marshes. Travancore tortoises are well camouflaged, 98% of the individuals found were hidden in vegetation, burrows or leaf litter which in turn deters our ability to detect them. Feeding ecology of Travancore tortoise was studied for four years (2006-2009) in the Anamalai hills, Western Ghats. The diet of the species was examined and quantified from their faecal matter and direct feeding observations. It was primarily herbivorous feeding on herbs, grass and fruits but also fed on animals including invertebrates (insects, millipedes, molluscs, scorpions and crabs) and carcass of vertebrates. Five individuals of Travancore tortoise (2 males and 3 females) were attached with transmitters and monitored between February 2008 and March 2010. The tortoises were located using portable radio telemetry receiver and hand held collapsible antenna. Home range sizes were estimated using 100 % minimum convex polygon (MCP) and 95 % Kernel. The MCP home ranges varied between 5.2 and 34 ha. Kernel home ranges were varied between 1.0 ha and 9.8 ha Location data of individual tortoises collected from radio-tracking were used to investigate their spatial and temporal movement. An intensive study area of 110 ha was marked and divided into 100 x 100 grids, the corners of each grid were permanently marked with paint on trees or rock. Microhabitat variables were collected within each 100 x 100 m grid. The maximum linear distance moved by radio tracked tortoise varied between 245 m and 665 m. Autologistic model analysis revealed that the spatial movement of Travancore tortoise was influenced by distance to the edge of evergreen and bamboo lantana grass habitat. Temperature loggers were programmed to collect temperature at intervals of 360 seconds. These loggers were attached on the carapace of the radio tracked tortoises using epoxy adhesive. Rainfall in the study area was measured to the nearest mm using a rain gauge. Velocity of movement was calculated between two radio locations. Generalized linear model (GLM) with binomial errors and logit link function was used to find out the factors influencing activity. Idiosyncrasies were found in the temporal activity of Travancore tortoise. The overall activity of all the four Travancore tortoises was positively influenced during monsoon and was negatively influenced by post monsoon and summer season. Rainfall, minimum and maximum did not have any direct influence on the TTs activity. The percentage monthly activity pattern of individuals appears to be seasonal, their activity was increased during the rainfall months (June to October) and reduced during the drier months (November to February). Evidence suggests that I. travancorica is facing exploitation. Removal of adults from the populations might affect the long term survival of the species. Ensuring protection of populations within the protected areas by creating more awareness among the protection staff and local people is needed. Grass marshes “vayals” are crucial microhabitats for the species to forage. Protection and monitoring should be of importance for the persistence of the tortoise population in the reserves. Little is known about their breeding biology and nesting in the wild. Future studies on their breeding biology will be important to understand their life history and breeding habitat requirements. The array of food intake by I. travancorica shows the complexity in their diet which needs to be taken into consideration while maintaining them ex-situ. Conservation breeding programs should be taken up in a coordinated manner by establishing multiple captive populations. A Conservation Action Plan is proposed based on the findings from the study.
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