oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Tigers Need Cover: Multi-Scale Occupancy Study of the Big Cat in Sumatran Forest and Plantation Landscapes  [PDF]
Sunarto Sunarto, Marcella J. Kelly, Karmila Parakkasi, Sybille Klenzendorf, Eka Septayuda, Harry Kurniawan
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0030859
Abstract: The critically endangered Sumatran tiger (Panthera tigris sumatrae Pocock, 1929) is generally known as a forest-dependent animal. With large-scale conversion of forests into plantations, however, it is crucial for restoration efforts to understand to what extent tigers use modified habitats. We investigated tiger-habitat relationships at 2 spatial scales: occupancy across the landscape and habitat use within the home range. Across major landcover types in central Sumatra, we conducted systematic detection, non-detection sign surveys in 47, 17×17 km grid cells. Within each cell, we surveyed 40, 1-km transects and recorded tiger detections and habitat variables in 100 m segments totaling 1,857 km surveyed. We found that tigers strongly preferred forest and used plantations of acacia and oilpalm, far less than their availability. Tiger probability of occupancy covaried positively and strongly with altitude, positively with forest area, and negatively with distance-to-forest centroids. At the fine scale, probability of habitat use by tigers across landcover types covaried positively and strongly with understory cover and altitude, and negatively and strongly with human settlement. Within forest areas, tigers strongly preferred sites that are farther from water bodies, higher in altitude, farther from edge, and closer to centroid of large forest block; and strongly preferred sites with thicker understory cover, lower level of disturbance, higher altitude, and steeper slope. These results indicate that to thrive, tigers depend on the existence of large contiguous forest blocks, and that with adjustments in plantation management, tigers could use mosaics of plantations (as additional roaming zones), riparian forests (as corridors) and smaller forest patches (as stepping stones), potentially maintaining a metapopulation structure in fragmented landscapes. This study highlights the importance of a multi-spatial scale analysis and provides crucial information relevant to restoring tigers and other wildlife in forest and plantation landscapes through improvement in habitat extent, quality, and connectivity.
Apes in Space: Saving an Imperilled Orangutan Population in Sumatra  [PDF]
Gail Campbell-Smith,Miran Campbell-Smith,Ian Singleton,Matthew Linkie
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017210
Abstract: Deforestation rates in Sumatra are amongst the highest in the tropics. Lowland forests, which support the highest densities of orangutans, are particularly vulnerable to clearance and fragmentation because they are highly accessible. Consequently, many orangutans will, in the future, live in strictly or partially isolated populations. Whilst orangutans have been extensively studied in primary forests, their response to living in human-dominated landscapes remains poorly known, despite it being essential for their future management. Here, we focus on an isolated group of critically endangered Sumatran orangutans (Pongo abelii) that co-exist with farmers in a mixed agroforest system consisting of degraded natural forest, smallholder (predominantly rubber) farms and oil palm plantations. Over 24 months we conducted the first ever spatial assessment of orangutan habitat use in the human-transformed landscape of Batang Serangan, North Sumatra. From 1,204 independent crop-raiding incidents recorded, orangutans showed strong foraging preference for mixed farmland/degraded forest habitat over oil palm patches. The core home range areas of the eight adult orangutans encompassed only 14% of the available study area. Monthly home range sizes averaged 423 ha (±139, SD) for males, and 131±46 ha for females, and were positively influenced by wild and cultivated fruit presence, and by crop consumption. The average daily distance travelled was similar for both adult males (868 m±350, SD) and females (866 m±195), but increased when orangutans raided crops. These findings show that orangutans can survive, demographically, in certain types of degraded landscapes, foraging on a mixture of crops and wild fruits. However, the poor quality habitat offered to orangutans by oil palm plantations, in terms of low food availability and as a barrier to female movements, is cause for concern since this is the land use type that is most rapidly replacing the preferred forest habitat across both Sumatran and Bornean orangutan ranges.
Movements and home range of the gaboon adder, Bitis gabonica gabonica, in Zululand, South Africa  [cached]
I.J. Linn,M.R. Perrin,T Bodbijl
African Zoology , 2011,
Abstract: Gaboon adders are active throughout the year, but are largely sedentary. In their prime habitat of forest–thicket–grassland mosaic in Zululand their normal foraging movements are short range, punctuated by long periods of inactivity. Occasional long distance movements suggest changes in foraging area, but these movements take place within a home range, to which the snakes show long-term fidelity. The snakes breed during the southern autumn, March to May. A male adder tracked during the breeding season performed a long, looping excursion well outside its home range. During this sally, through marginal to poor habitats and prime terrain, movements were rapid, with only short spells of inactivity, and little apparent foraging behaviour. This excursion is interpreted as mate-seeking with males actively searching for sedentary females.
Movements, Home-Range Size and Habitat Selection of Mallards during Autumn Migration  [PDF]
Daniel Bengtsson, Alexis Avril, Gunnar Gunnarsson, Johan Elmberg, P?r S?derquist, Gabriel Norevik, Conny Tolf, Kamran Safi, Wolfgang Fiedler, Martin Wikelski, Bj?rn Olsen, Jonas Waldenstr?m
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0100764
Abstract: The mallard (Anas platyrhynchos) is a focal species in game management, epidemiology and ornithology, but comparably little research has focused on the ecology of the migration seasons. We studied habitat use, time-budgets, home-range sizes, habitat selection, and movements based on spatial data collected with GPS devices attached to wild mallards trapped at an autumn stopover site in the Northwest European flyway. Sixteen individuals (13 males, 3 females) were followed for 15–38 days in October to December 2010. Forty-nine percent (SD = 8.4%) of the ducks' total time, and 85% of the day-time (SD = 28.3%), was spent at sheltered reefs and bays on the coast. Two ducks used ponds, rather than coast, as day-roosts instead. Mallards spent most of the night (76% of total time, SD = 15.8%) on wetlands, mainly on alvar steppe, or in various flooded areas (e.g. coastal meadows). Crop fields with maize were also selectively utilized. Movements between roosting and foraging areas mainly took place at dawn and dusk, and the home-ranges observed in our study are among the largest ever documented for mallards (mean = 6,859 ha; SD = 5,872 ha). This study provides insights into relatively unknown aspects of mallard ecology. The fact that autumn-staging migratory mallards have a well-developed diel activity pattern tightly linked to the use of specific habitats has implications for wetland management, hunting and conservation, as well as for the epidemiology of diseases shared between wildlife and domestic animals.
Testing reintroduction as a conservation strategy for the critically endangered Chinese alligator: Movements and home range of released captive individuals
ZhengHuan Wang,Hong Yao,YouZhong Ding,John Thorbjarnarson,XiaoMing Wang
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4615-8
Abstract: The Chinese alligator (Alligator sinensis) is considered the most critically endangered crocodilian as a result of the near total loss of its habitat and its extremely small and fragmented wild populations. Plans for population recovery lie mostly with wetland restoration and the reintroduction of captive-reared animals. We carried out a first-trial release of 3 adult Chinese alligators (1♂, 2♀) into a pond at the Hongxing conservation site, Xuancheng, southern Anhui Province; the animals were radio-tracked from May to October in 2003. We hypothesized that after a period of adaptation, the alligators would establish definable home ranges. Two (1♂, 1♀) of the 3 alligators were monitored for the whole of the tracking period. The male had an annual home-range size of 7.61 hm2, and the female 4.00 hm2. Water temperature and pond water level were two important factors influencing the alligators’ distributions, and daily movements. The radio-tracked alligators had overlapping home ranges, which notably included the one substantial island in the pond; that island is the only known nesting site of the local native wild alligators. Aggressive interactions between the released alligators and native wild alligators were observed during the breeding season around this island. All the three reintroduced alligators survived the winter of 2003 and were alive in the same pond in 2008. We concluded that the Hongxing conservation site provided a suitable habitat for the reintroduced alligators. However, the low water level in the pond resulting from farmland irrigation in August and September can be a substantial threat to the alligators’ survival. Therefore, regulations on irrigation in summer and autumn are needed to balance the water needs of the alligators and agriculture.
A radio tracking study of home range and movements of the marsupial Micoureus demerarae (Thomas) (Mammalia, Didelphidae) in the Atlantic forest of south-eastern Brazil
Moraes Junior, Edsel Amorim;Chiarello, Adriano Garcia;
Revista Brasileira de Zoologia , 2005, DOI: 10.1590/S0101-81752005000100011
Abstract: from august 2001 to july 2002 the home range and movements of seven micoureus demerarae (thomas, 1905) (three males and four females) were investigated using radio tracking in the uni?o biological reserve, state of rio de janeiro, south-eastern brazil. a total of 436 locations was obtained and home range estimated with fixed kernel (95% of data points), and minimum convex polygon (mcp) methods, with 100 and 95% of data points. male home ranges estimated by mcp (100%) ranged from 5.4-24.2 ha and females from 0.3-10.7 ha. corresponding figures calculated with kernel (95%) were 4-10.9 ha for males and 1.3-5.9 ha for females. animals travelled on average 423 m/night, with males travelling significantly further (582.8 m/night) than females (335.1 m/night) (t test, t = 3.609, p = 0.001). we concluded that radio tracking produced much larger home ranges than those estimated with traditional live-trapping techniques, suggesting that the latter might underestimate ranging when the area covered with traps is relatively small (ca. 1 ha or less). radio tracking also indicated that m. demerarae, although predominantly arboreal and weighting only ca. 130 g., has movements similar in magnitude to larger-sized terrestrial didelphimorph marsupials, such as didelphis linnaeus, 1758, philander linnaeus, 1758 and metachirus (desmarest, 1817).
Effect of Captive Environment on Plasma Cortisol Level and Behavioral Pattern of Bengal Tigers (Panthera tigris tigris)
S. Sajjad, U. Farooq1*, M. Anwar, A. Khurshid2 and S.A. Bukhari1
Pakistan Veterinary Journal , 2011,
Abstract: Captive environment in zoological parks often do not provide optimum conditions for natural behaviors due to spatial constraints and negative public reaction. These factors elicit stereotypic behavior in tigers such as pacing, head bobbing and aimless repetition of some movements, and are considered to be an indication of stress. The present study was conducted to assess the effect of captivity on the plasma cortisol level and behavioral pattern in Bengal tigers (Panthera tigris tigris). Tigers kept in captivity at the Lahore zoo (n=4) and in semi natural environment at the Lahore Wildlife Park (n=6) were used for this study, and standard protocols of housing and sampling were observed. The mean plasma cortisol values for the captive animals and those kept in a semi natural environment were 34.48±1.33 and 39.22±3.16μg/dl, respectively; and were statistically non significant. Similarly, no significant difference in the plasma cortisol levels was observed among the individuals within each form of captivity. From the behavioral survey it was observed that the time spent in pacing and resting was much longer for captive animals than animals confined to the semi natural environment. Thus, Technically monitored “Environmental Enrichment’ plans need to be devised which are as close as possible to the natural environment of the captive animals in order to achieve their utmost performance.
The Home Range and Movements of Giant Otters (Pteronura brasiliensis) in the Xixuan Reserve, Roraima, Brazil
Emanuela Evangelista,Fernando C.W. Rosas
IUCN Otter Specialist Group Bulletin , 2011,
Abstract: A population of Giant otter was studied in the central Brazilian Amazon at the Xixuaú Reserve, Roraima (0o48’S, 61o33’W), in order to gather preliminary information on spatial use of habitat. Through the period 2000–2003, 80 animals have been recorded in the study area, of which 9 solitary (11.2%) and 71 (88.7%) in groups of an average of 4.46 individuals (n=15; biggest group=9). For 4 Giant otter groups, dry season home ranges were estimated at approximately 8 km in average (n=6; minimum size 4.6 km, maximum size 10.5 km), along watercourses of 52.8 m of average width (n=8). Groups’ home ranges in the study area can overlap. An expansion in direction of flooded forest areas has been observed during the flooded season as well as a temporary contraction during the period of cub rearing. The periodic and complete counting of the animals allowed estimating the density of the species in the study area (1 animal/1km).
Spatial behaviour and survival of translocated wild brown hares  [PDF]
Fischer, C.,Tagand, R.
Animal Biodiversity and Conservation , 2012,
Abstract: The fragility of many populations of brown hares in Western Europe is a concern for managers, hunters and naturalists. We took advantage of a locally high density population to use wild individuals to restock areas where the species had disappeared or was close to disappearing. The aim of the project was to assess the evolution of the spatial behaviour after release using radio–tracking. Over 150 wild brown hares were translocated, one third of which were fitted with radio collars. In addition, fifteen individuals were radio–tagged and released back into the source population as a control. Most individuals settled in less than two months and their seasonal home range, once settled, was similar to that observed in the source population. Mean duration of tracking was not significantly different between the two groups. Moreover, two years after the last translocation, tagged individuals can still be observed, but most hares present are not tagged, which indicates natural reproduction of the released individuals. The translocation of wild individuals thus appears to give encouraging results.
Seasonal Movements and Home Range Sizes of Korean Field Mouse Apodemus peninsulae in Unburned and Post-Fire Pine Planted Stands Within a Pine Forest
Eun Jae Lee,Shin-Jae Rhim,Woo-Shin Lee
Journal of Animal and Veterinary Advances , 2012, DOI: 10.3923/javaa.2012.3834.3839
Abstract: The seasonal movements and home ranges of Korean field mice Apodemus peninsulae in unburned and post-fire pine planted stands within a pine forest were studied via the radio-tracking of 56 mice for 12 months in South Korea. Seasonal movement distances were significantly longer in the post-fire pine planted stand than in the unburned stand in each season and did not differ between males and females over the 4 seasons. In both stands, the activity patterns and duration of movement also differed significantly over the 4 seasons. Home range sizes were largest in autumn and smallest in Winter. Seasonal home range sizes were significantly larger in the post-fire pine planted stand than in the unburned stand in each season. No differences in home range size between males and females were noted in either of the experimental stands. Post-fire silvicultural practices affect forest-floor small rodents in the early stages after the planting of pine seedlings. Studying space use patterns over longer time periods will provide a better sense of the long-term impacts of post-fire silvicultural practices on small rodents within pine forests.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.