Evaluation of GPS collar performance by stationary tests and fitting on free-ranging Japanese black bears

YAMAZAKI, K.; KASAI, S.; KOIKE, S.; GOTO, Y.; KOZAKAI, C.; FURUBAYASHI, K. 2008. Evaluation of GPS collar performance by stationary tests and fitting on free-ranging Japanese black bears. Mammal Study 33:131-142.

Abstract. We evaluated the performance of two GPS collars as a tool for studying Japanese black bears (Ursus thibetanus japonicus) in the Kanto region, Japan. Collars were placed at five stationary points to test the effects of GPS antenna orientation and degree of canopy closure on the fix rate and the positional error, and collars were deployed on 16 free-ranging bears to examine the fix rate and the effects of fix interval on fix rate. In the stationary tests, the proportions of no fix and of 2D fix (vs. 3D fix) increased as canopy closure increased and antenna orientation was further from vertical; at an antenna angle =90° from the vertical and canopy closure of 76.2–79.1%, the fix rate was <50%. The positional error for 3D fixes (ranged from 6.84 to 16.43 m) was significantly lower than that for 2D fixes (ranged from 30.74 to 43.45 m), and the positional error for both was affected by canopy closure and GPS antenna angle. An expected multipath effect on positional errors by rain was not statistically significant. Mean fix rates on collared bears ranged from 23.6% to 56.4% and were significantly lower than those in the stationary test. The fix rates at 5-min intervals were significantly higher than those at 4-hr intervals. Although our tests revealed some limitations and biases, GPS collar appears suitable for studying the movement and behavior of the bears.

Response of leopards to re-introduced tigers in Sariska Tiger Reserve, Western India

MONDAL, K.; GUPTA, S.; BHATTACHARJEE, S.; QURESHI, Q; SANKAR, K. 2012. Response of leopards to re-introduced tigers in Sariska Tiger Reserve, Western India. International Journal of Biodiversity and Conservation 4(5):228-236. doi: 10.5897/IJBC12.014

Abstract. Tigers got exterminated from Sariska Tiger Reserve before 2005. After that, five tigers were re-introduced to Sariska during 2008 to 2010. The present study compared the abundance, site occupancy and temporal activity pattern of leopard before and after tiger re-introduction. The population of leopard was estimated by mark-recapture technique using camera traps during 2008 to 2010 in an effective trapping area of 223.3 km2. Before tiger re-introduction (2008), the leopard density was estimated to be 7.6±0.6 (SE) /100 km2 and after tiger reintroduction it was 6.2±0.8 /100 km2(2009) and 3.1±0.4 /100 km2 (2010). It was observed that the density of leopard declined significantly (Two sample T-Test; P = 0.0002) from 2008 to 2010. Rate of site occupancy was calculated through site-wise capture history of leopard obtained from camera traps. Before tiger re-introduction the probability of site utilization of leopard was 0.75, while after tiger re-introduction probabilities of site utilization of leopard and tiger were estimated at 0.54 and 0.52 respectively and the co-occurrence of both the species was 0.51. Temporal activity patterns of tiger and leopard were investigated from photo captures. Prior to the release of tigers, mean activity time of leopard was 20: 57 h (95% CI 20: 19 to 22: 53) but shifted to 22: 35 h (21: 02 to 01: 25 h) after tiger release (Watson’s U2 test: p<0.005). The present study showed that there was a decline in the leopard population after tiger re-introduction and considerable segregation between the two carnivores along the spatial and temporal axes.

Arboreal tropical forest vertebrates: current knowledge and research trends

KAYS, R.; ALLISON, A. 2001. Arboreal tropical forest vertebrates: current knowledge and research trends. Plant Ecology 153:109-120.

Abstract. We review the ecology and specialized methods required for studying arboreal mammals, birds, reptiles and amphibians, and use faunal checklists from 12 tropical wet forest sites and an analysis of all articles published during the past ten years in 14 major journals to assess current knowledge and general research trends for these groups. The percentage of arboreal vertebrates was remarkably similar at the different sites (76.2+/-3.9%). Birds were the most arboreal group and amphibians and reptiles the least. The review of journals showed that primates were overwhelmingly the most studied group (336 papers), followed by bats (105), passeriform birds (73) and rodents (55). Judging by their portion of the arboreal vertebrate community and the number of papers surveyed, birds and amphibians and reptiles are vastly understudied compared to mammals, but this is largely due to the great number of primate studies. The number of publications on arboreal vertebrates has remained relatively stable over the last 10 years for all taxa except primates, which have seen a growth in publications. Canopy vertebrates from Brazil had by the most publications (120), followed by Madagascar (61), Costa Rica (55) and Indonesia (42). We conclude by highlighting the priorities we see for future studies on tropical canopy vertebrates.

The Brazilian Caatinga in South American zoogeography: tropical mammals in a dry region

MARES, M.A.; WILLIG, M.R.; LACHER JR., T.E. 1985. The Brazilian Caatinga in South American zoogeography: tropical mammals in a dry region. Journal of Biogeography 12:57-69.

Abstract. Recent research in South American biogeography on groups other than mammals suggests that the semi-arid Caatinga of northeastern Brazil provided xeric refugia during mesic phases of the Pleistocene climatic cycles. If this supposition is correct, the Caatinga mammal fauna might be expected to contain numerous species showing a pronounced level of adaptation to aridity and the origins of a substantial segment of the fauna slr~ould be traceable to the diversification and eventual speciation that would be expected to have resulted from extended isolation in a xeric environment. An analysis of the extant mammal fauna fails to corroborate these predictions; only one endemic mammal species is found in the Caatinga, and the fauna lacks the expected physiological and morphological adaptations. Other vertebrate groups also exhibit low levels of endemism. The high degree of climatic unpredictability that is characteristic of the Caatinga may preclude the development of a unique fauna adapted to xeric conditions. It appears that the present inhabitants of the region avoid the environmental effects of aridity and climatic unpredictability during harsh periods by utilizing the numerous mesic enclaves scattered throughout the Northeast. Indeed, even during periods of elevated precipitation, most mammal species reach their highest density in these relatively restricted areas. Although the Caatinga contains a xeric-adapted flora, it harbours an anomalous mammal fauna that is more characteristic of a mesic tropical biome in terms of both species composition and overall adaptation. The development of an assemblage of vertebrates whose adaptations do not parallel those of the dominant flora in a region is an unusual situation which should be of particular interest to palaeontologists attempting to reconstruct ancient environments.