50 likes | 360 Views
Crouching Tigers Hidden Prey: Sumatran tiger and prey populations in a tropical forest landscape . Paper by: Timothy G. O’Brien, Margaret F. Kinnaird, and Hariyo T. Wibisono Animal Conservation 2003 131-139 Presented by: Caroline Mullis Geography Major Geog 370. Spatial Problem.
E N D
Crouching Tigers Hidden Prey: Sumatran tiger and prey populations in a tropical forest landscape Paper by: Timothy G. O’Brien, Margaret F. Kinnaird, and Hariyo T. WibisonoAnimal Conservation 2003 131-139 Presented by: Caroline Mullis Geography Major Geog 370
Spatial Problem • Problem: Looking at the distribution and abundance of Sumatran tigers and nine prey species in Selatan National Park, in Sumatra, Indonesia • Hypothesis: Habitat loss and illegal hunting of prey and the tigers are responsible for the observed patterns of abundance (decrease).
Methods, Data, and Test • Method: Use of passive infared camera-traps to assess abundance and distribution of tigers relative to prey availability, park boundaries and density of human population. • Cameras set in 10 by 2 km sampling blocks, oriented from park boundary toward park interior to detect edge effects. • Photo taken when sensor triggered, dated and timed. Traps left for 35 days. • Cameras were retrieved from locations filmed examined for tigers and prey • RAI- relative-abundance indices were calculated from the number of independent photographs of a species with number of days it took to acquire. (measured effort expected to increase as density decreased) • Same area was sampled before, and goal was to compare camera trap abundance indices with density estimates from using the CAPTURE method previously developed by Nichols (1998). • Used linear regression on RAI
Results • Using CAPTURE model to determine density within sampling area • Results found that tiger abundance varied with abundance of large prey (pigs), strong correlation. • RAI-2 four times higher for tigers in areas of low human density. • Goal of study first to demonstrate that abundance of tigers and prey are directly related to independently derived estimates of densities, and show influence of human densities on abundance.
Conclusions • Need for monitoring habitat conditions, prey populations, and monitoring poaching will help prevent the furthering of the endangerment of the tigers. • Criticisms: effective use of camera traps and good explanation of RAI’s but lack of original conclusion. Useful to include further suggestions of remedies.