Title page for ETD etd-62397-172421

Type of Document Dissertation
Author Sumithran, Stephen
Author's Email Address sumtran@vt.edu
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
  • Forage Preference
  • Habitat Use
  • Western Ghats
  • India
  • Nilgiris
  • Nilgiri tahr
  • GIS
  • Predators
Date of Defense 1997-07-18
Availability restricted
The 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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