Type of Document Dissertation Author Sumithran, Stephen Author's Email Address firstname.lastname@example.org URN etd-62397-172421 Title Status and Ecology of the Nilgiri Tahr in the Mukurthi National Park, South India Degree PhD Department Fisheries and Wildlife Sciences Advisory Committee
Advisor Name Title Giles, Robert H. Jr. Murphy, Brian R. Scanlon, Patrick F. Stauffer, Dean F. Wynne, Randolph H. Fraser, James D. Committee Chair Keywords
- Forage Preference
- Habitat Use
- Western Ghats
- Nilgiri tahr
Date of Defense 1997-07-18 Availability restricted AbstractThe Nilgiri tahr (Hemitragus hylocrius) is an endangered
mountain ungulate endemic to the Western Ghats in South India.
I studied the status and ecology of the Nilgiri tahr in the
Mukurthi National Park, from January 1993 to December 1995.
To determine the status of this tahr population, I conducted
foot surveys, total counts, and a three-day census and
estimated that this population contained about 150 tahr.
Tahr were more numerous in the north sector than the south
sector of the park. Age-specific mortality rates in this
population were higher than in other tahr populations.
I conducted deterministic computer simulations to determine
the persistence of this population. I estimated that under
current conditions, this population will persist for 22 years.
When the adult mortality was reduced from 0.40 to 0.17, the
modeled population persisted for more than 200 years.
Tahr used grasslands that were close to cliffs (p <0.0001),
far from roads (p <0.0001), far from shola forests
(p <0.01), and far from commercial forestry plantations
(p <0.001). Based on these criteria I mapped the suitability
of tahr habitat using a GIS and estimated that only 20% of
the park area had >50% chance of being used by tahr.
I used the GIS to simulate several management options to
improve the quality of tahr habitat. Suitable habitat for
tahr increased two-fold when roads within the park were
closed to vehicular access. Similarly, removal of
commercial forestry plantations also resulted in a two-fold
increase of suitable habitat, and finally when both road
access was restricted and commercial forests were removed,
suitable tahr habitat increased three-fold. I used
micro-histological analysis on tahr fecal pellets to
determine food habits. Grasses constituted 64.2% of their
diet. Five plant species (Eulalia phaeothrix, Chrysopogon
zeylanicus, Ischaemum rugosum, Andropogon sp., and Carex sp.)
accounted for 84.6% of the tahr' diet. These species were
found in higher densities in the grasslands of the
north sector than the south sector of the park (p <0.001).
Predators such as leopard (Panthera pardus) and tiger
(Panthera tigris), killed and consumed tahr.
Tahr constituted 56% of the leopards' diet and 6% of the
tigers' diet. I estimated that leopards and tigers in the
park killed and consumed 30 to 60 tahr per year, and this
accounted for 19% to 38% of the tahr population. The tahr
population in the park has undergone a decline, possible
causes for this decline includes high mortality from
predation and poaching and loss of habitat.
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