1 / 21

Home Ranges of Sloth Bears in Nepal:

Home Ranges of Sloth Bears in Nepal:. Implications for Conservation R., Joshi, D. L. Garshelis , and J. L. D. Smith Journal of Wildlife Management 59:204-214. 1995. Thomas A. W. Enright Department of Wildlife, Sustainability, and Ecosystem Sciences Tarleton State University (651) 357-2611

gurit
Télécharger la présentation

Home Ranges of Sloth Bears in Nepal:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Home Ranges of Sloth Bears in Nepal: Implications for Conservation R., Joshi, D. L. Garshelis, and J. L. D. Smith Journal of Wildlife Management 59:204-214. 1995 Thomas A. W. Enright Department of Wildlife, Sustainability, and Ecosystem Sciences Tarleton State University (651) 357-2611 thomas.enright@go.tarleton.edu

  2. Bear Conservation • Many populations are declining • Habitat degradation and poaching are a constant threat • Large home ranges increasing vulnerability • Sloth Bears are the only myrmecophagousUrsids

  3. Why is this relevant? • Characteristics of species of concern • Large home range size • Large body size • Why does it matter? • Little is known about sloth bear populations • Unique • fragmentation and degradation occurring at a rapidly increasing rate

  4. Sloth Bear(Melursusursinus) • Range = Indian subcontinent • Size =273 lbs • Myrmecophagous – diet of ants and termites • Morphological adaptations • Lack 2 upper incisors • Long claws • Long shaggy coat • Behavioral adaptations • Nocturnal activity • Extended parental care, carrying young on back • Small home range to body size

  5. Piece in the Puzzle Bears • Large home ranges • Large seasonal shifts • Human-wildlife conflict As a myrmecophagous species… Where do sloth bears fit?

  6. Research Importance • IF sloth bears: • exhibit large home ranges and seasonal shiftsthen large protected areas and corridors are vital for their conservation • more sedentary  small preserves are beneficial

  7. Study Site • Royal Chitwan National Park, Nepal (1973) • 3 river systems • 932 km2 preserve • Subtropical climate • Annual rainfall 245 cm

  8. Study Site • Habitat Classification • soil type, moisture, and disturbance • Alluvium • Floodplain forest • Tall grass • Sal Forest • Dry Upland • The study area was composed of 70% sal forest, 22% tall grass, and 8% riverine forest • Outside Royal Chitwan National Park • Degraded forest • Heavy livestock grazing

  9. Methods:Capture and sample size • Capture • Trapping • Barrel traps • Aldrich foot snares • Dart gun • Immobilization • Intramuscular injection of Ketamine and Xylazine

  10. Radio Telemetry and Home Range • Radio tracking • Independent locations • 2 times per week • Locations > 1 day apart 2. Dependent monitoring • 1-3 12 hr. sampling sessions per individual • Locations every 15 min • Home Range Analysis • All locations • Native habitat: simple convex polygons (Odum and Kuenzler 1955, Worton 1987) • Mixed habitats: minimum-perimeter polygons (Odum and Kuenzler1955, Worton1987) • Benefits: • Continuity with other bear studies

  11. Measuring Seasonal Variation • Defining the seasons • Wet season (May to November) • Dry season (December to April) • Seasonal Shifts • Distance • seasonal activity centers: mean (X, Y) coordinates • Extent • Distance/ home range length • Frequency of habitat use • Percent of locations in each habitat type

  12. Statistics • Nonparametric statistical methods • Wilcoxon signed rank tests – changes within individual ranges • Mann-Whitney U-tests – compare male and female All comes down to the P-value!

  13. Results • 18 sloth bears radiocollared • Continuously monitored SEASONAL MOVEMENT • Males • 6 of 8 exhibited seasonal movements • 2 that did not were the smallest and youngest bear • Female • 1 of 6 females seasonally migrated • Others made brief movements on the edge or into sal forests

  14. Fig. 1 Seasonal home range shifts of 4 sloth bear. Male 608 exemplifies the wet season shift characteristic of most males. 616 was a small male that expanded its range but not to Sal. 620 was one of the few females that shifted. 604 exhibited no seasonal shift typical of females.

  15. Results SEASONAL USE OF HABITATS • Male and female occupied sal forest more during the wet season • (M Wilcoxon n=15 pairs, P <0.001) • (F Wilcoxon n=15 pairs, p = 0.007) • Males (79%) used sal > females (13%) during the wet season • (U-test P = 0.002) Fig. 2

  16. Results • HOME RANGE SIZE • Males wet season > female (t =2.83, 25 df, P = 0.009) • Male and female wet season > dry season (M paired t = 3.96, 9 df, P = 0.003) (F paired t = 2.34, 10df, P = 0.04) • SEASONAL SHIFT • Seasonal shifts proportional to home range size (t =1.88, 23 df, P = 0.07)

  17. Discussion • Sloth Bears are set apart from other myrmecophages and Ursids • Myrmecophages • Inobligate • shift home range • Ursids • Smaller shifts • < 2 km versus > 6 km • Smaller home range • REASONS: • sloth bear food varies less than black bear • habitats providing seasonally variable conditions were in closer proximity in Chitwan

  18. Discussion • Why a shift in seasonal movement and home range size? • Food availability • Flooding • Foraging efficiency

  19. Concluding Thoughts • Sloth Bear Do! • Make seasonal shifts • Maintain small home ranges • Sex and seasonally specific Conservation Considerations • Home range and movement • Limiting factors • Habitat fragmentation • Food availability • Habitat type Small preserves cannot be overlooked

  20. Literature Cited • Garshelis, D. L. 1983. The role of sampling intensity in the selection of a home range model. Int. Conf. Wildl. Biotelem. 4:270-275. • Hogg, E. A. and R. V. Tanis. 1997. Probability and statistical inference: 5th edition. Prentice Hall. New Jersey. USA. • Odum, E. P. and E. J. Kuenzler. 1955. Measurement of territory and home range sizes in birds. Auk 72:128-137. • Worton, B. J. 1987. A review of models of home range for animal movement. Ecological Modeling 38:277-298.

  21. Questions?

More Related