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Context. Mediterranean areas offer a mosaic of favourable microhabitats to reptiles (e.g. open zones, thorny bushes) and are considered as biodiversity hotspots for these organisms. However, in these dry and hot environments, reptiles remain sheltered most of the time. They generally escape observation, posing difficulties to perform inventories. Trap sampling or rock-turning surveys commonly used to detect reptiles entail important logistical constraints, may perturb fragile microhabitats, and are not appropriate for chelonians. Alternative simple and cost-effective methods are desired.
Aims. We tested the efficiency of camera trapping in a dry Mediterranean landscape, notably to detect threatened Hermann’s tortoises. We tested whether small artificial freshwater ponds could attract animals in the field of view of the cameras to increase detectability. We also tested whether sand tracks survey around ponds could improve the method.
Methods. We used a small number of cameras with ponds (5 in 2011, 7 in 2012), thereby maintaining low logistical costs. We randomly filled three ponds and emptied three ponds every 7 days. We set the time-lapse function of each camera with an interval of 5 min and inspected the sand tracks every 2 or 3 days. We used information from 39 radio-tracked tortoises to better estimate the detectability performances of the camera–pond system.
Key results. This technique was effective to detect tortoises (n = 348 observations) and five other reptiles (among the 11 species present in the study area). Large numbers of birds and mammals were observed (n = 4232, n = 43 species at least), thereby increasing the biodiversity list of the surveyed area. We detected 28% of the radio-tracked tortoises present in the monitored area. Filled ponds were more attractive and sand track survey completed camera monitoring.
Conclusions. Camera trapping associated with small ponds represent a useful tool to perform rapid inventories of the fauna in Mediterranean habitats, especially to detect the emblematic Hermann’s tortoise and other cryptic reptiles (e.g. snakes).
Implications. The low cost–efficiency ratio of this method allows performing multiple counting surveys, and thus may help collect robust data necessary to justify the protection of key habitats that are coveted by property developers.
Context. The value of captive breeding for recovery programs of endangered carnivorous mammals is often questioned because of low post-release survival reported for founder animals following translocation.
Aims. The aim of the present study was to test the effect of rearing method on survival and body mass of captive-raised Tasmanian devils (Sarcophilus harrisii) following release on an offshore island. We also compared the post-release diet of these devils with the diet of wild devils on mainland Tasmania, where a similar array of diet items is available.
Methods. Twenty-eight captive-raised devils were released onto the island; 19 had been raised in intensive captive-management facilities (IC) and nine in free-range (22 ha) enclosures (FRE). Survival and body-mass change were compared between IC and FRE for up to 440 days post-release. Devil diet was assessed via scat analysis.
Key results. A high proportion (96%) of the founders survived 1 year post-release. Pre-release captive-rearing method had no effect. Released devils gained an average of 14% of their original body mass, irrespective of captive-rearing method. There was very little difference in the diet of captive-reared devils released onto Maria Island relative to wild mainland devils: Tasmanian pademelon, Thylogale billardierii, was the primary food item for both.
Conclusions. The intensity of captive rearing did not affect the survival of devils released onto Maria Island. This suggests that even devils held in IC facilities retain the innate behaviour required to scavenge and hunt prey, and therefore maintain bodyweight post-release. The lack of any threatening processes on the island is also likely to have contributed to the high survival rate 2 years post-release.
Implications. Our study provided preliminary evidence that the release of captive-raised Tasmanian devils onto off-shore islands is a viable conservation action. Captive-breeding programs and captive-raised founders can play a viable and valuable role in the conservation action plans for recovery programs of endangered carnivorous mammals.
Context. Control of unwanted wildlife (‘pest’ animals) is undertaken for conservation and economic reasons, and when such animals are considered a nuisance. Such control should be undertaken using approaches that minimise, as far as possible, detrimental impacts on the welfare of the animals. Using a scientific framework based on the Five Domains model, the relative welfare impacts of pest control methods can be compared across methods and pest species.
Aims. We demonstrate the application of a modified version of this framework to evaluate the relative impacts of seven Vertebrate Toxic Agents (VTAs) used to control brushtail possums (Trichosurus vulpecula) in New Zealand. The evaluation is used to produce a ranking of the seven VTAs based on their relative impacts on possum welfare.
Methods. Scientific literature describing mode of toxic action, specific effects in possums or other animals and reports from human poisonings was collated as reference material for a panel of six experts. The panel produced a median welfare impact score (‘none’ to ‘extreme’) for each of the Five Domains. The ‘Overall Grade’ (1 to 8) reflected the intensity and duration of all impacts of a VTA on possums.
Key results. All VTAs evaluated have at least moderate impacts on possum welfare, lasting for at least minutes. Cyanide was assessed as having the lowest welfare impacts (median grade 4), and cholecalciferol and the anticoagulants the highest impacts (7.5 to 8). Zinc phosphide was assigned an intermediate grade (6) with high confidence. While the overall impacts of sodium fluoroacetate (1080) and phosphorus were also assessed as intermediate (6), the panel’s confidence in these scores was low.
Conclusions. From an animal welfare perspective, anticoagulant poisons and cholecalciferol should be the least preferred options for controlling possums in New Zealand, as VTAs with less severe welfare impacts are available.
Implications. The results of such assessments allow animal welfare impacts to be integrated with other factors in wildlife management decision-making and policy development, and are thus useful for managers, researchers, regulators and operators. Evaluation of welfare impacts aligns with the goals and mandates of ethical wildlife control and may also be valuable in wider wildlife research and management activities.
KEYWORDS: area-corrected autocorrelated kernel density estimation, Asian elephant, Bukit Tigapuluh, elephant conservation, Elephas maximus sumatranus, habitat preference, movement behaviour, ranging behaviour, resource selection
Context. Understanding ranging behaviour and habitat selection of threatened species is crucial for the development of conservation strategies and the design of conservation areas. Our understanding of the actual needs of the critically endangered Sumatran elephant in this context is insufficient.
Aims. Provide reliable subspecies-specific information on home range size and habitat selection of Sumatran elephants.
Methods. Using both the new area-corrected autocorrelated kernel density estimation (AKDEC) and two commonly applied conventional methods, the home range sizes of nine Sumatran elephants were estimated. Elephant habitat selection was studied using Manly’s selection ratios.
Key results. AKDEC home ranges of adults ranged from 275 km2 to 1352 km2. Estimates obtained using conventional KDE and minimum convex polygon (MCP) ranged between 156 km2 and 997 km2. Overall habitat selection was significant for both slope and land-cover type, whereas individual preferences varied to some extent. On the basis of global selection ratios, we found natural forest, pulpwood plantations and gentle slopes (≤4°) to be significantly selected, whereas most areas affected by human activities and steeper slopes were avoided by the majority of animals included in the study.
Conclusions. As expected, AKDEC estimates were much larger than those obtained using conventional methods because conventional methods have a tendency to underestimate home range size when confronted with autocorrelated movement data and produce estimates that refer to the limited study period only, whereas AKDEC estimates include the predicted animal’s long-term space use. The extremely large AKDEC estimate obtained for a subadult male most likely represents a combination of population dispersal range and temporary home range rather than its final adult home range. Regardless, it appears that Sumatran elephants roam over much larger areas than previously assumed. Natural forests and relatively flat areas are of great importance for Sumatran elephants. The observed intensive use of pulpwood plantations by one individual is likely because of limited availability of alternative suitable habitats.
Implications. A landscape-wide approach to elephant conservation that takes large home ranges into account, is required, and should include forest protection and restoration and elephant friendly management of existing pulpwood concessions, with special focus on areas with relatively gentle slopes.
The eastern grey kangaroo is a common and iconic species of Australia. Its specialised behaviour and reproduction have evolved as adaptations to the Australian environment, allowing the species to survive and flourish, despite wide climatic and seasonal variations in habitat. Across its range, the eastern grey kangaroo is harvested and subjected to population management for a variety of reasons, including localised over-abundance, livestock competition, crop grazing, native habitat conservation, animal welfare and direct threats to human safety. Population management of kangaroos is most commonly undertaken by shooting, although other methods such as reproductive control, translocation and repellents may also contribute successfully to management. Kangaroo harvesting and population control are controversial and divisive, because the kangaroo is perceived as both a national icon and as a pest species. Although a limited number of surveys have been undertaken on attitudes towards kangaroos and their management, the socio-political aspects affecting these issues are yet to be systematically investigated. Within this review we discuss the relevance of culture and language to species management and conservation, as well as the importance of scrutiny of stakeholder perceptions, motivations and values. Future directions should examine human dimensions that influence kangaroo-management decisions and conservation. The following three key aspects are recommended as research and management priorities: (1) experimental determination of whether gaps exist between actual and perceived impacts of kangaroo populations, (2) empirical investigation of how stakeholder language, culture, identity and values influence perceptions of kangaroos and their management, and (3) where population control is determined to be necessary, an incorporation of stakeholder differences within decision making to ensure best outcomes for both species conservation and population management.
Context. Supplementary feeding and baiting of wild ungulates is a common management practice. Wild boar is among the most frequently fed species and its numbers are rapidly increasing throughout Europe. It has been suggested that supplementary feeding throughout the year can have intentional and unintentional impacts on the species as well as on European forests and agricultural landscapes, and biodiversity. It is, therefore, important to identify the dependence of wild boar on supplemental foods to determine and predict its feeding patterns under alternative population and land-use management scenarios.
Aims. We investigated the diet composition of wild boar from stomach contents to identify its dependence on food resources of human origin (i.e. agricultural crops and supplemental foods) throughout the year in the Czech Republic.
Methods. We collected 345 samples from four study sites during spring, summer and winter seasons, over a 3-year period, and from different wild boar ages and sex classes.
Key results. Foods of human origin (mainly cereals) were the dominant food category and constituted the bulk of wild boar diet throughout the year (>50% of total stomach-content biomass), especially in winter, and in all the study sites. Cereals found in the stomachs of wild boar in summer might come from both crop fields as well as supplementary feeding. However, cereals identified in the stomachs in winter and spring come predominantly from baiting and supplementary feeding conducted by hunters. Cereals were consumed in different proportions by different ages and sexes. Males fed on cereals more than did females, whereas juveniles depended on such food less than did subadults.
Conclusions. Our finding of a consistent dependence of wild boar on food of human origin throughout the year in all study sites confirmed that supplementary feeding is important in the diet, which is a potential reason for the rapid increase of wild boar numbers in the Czech Republic.
Implications. Wildlife management agencies need to target feeding practices and design restrictive measures for supplementary feeding and baiting of wild boar in the Czech Republic. This should include defining maximum amounts of food and precise periods for supplementary feeding, and reducing non-target species at feeding sites.
Increased scrutiny of animal welfare in wildlife management has seen a recent proliferation in the use of procedural documents (standard operating procedures, codes of practice etc.). Some procedural documents are presumed to represent ‘best practice’ methods, whereby adherence to prescribed inputs is explicitly purported to generate humane outcomes. However, the relationship between what is done to animals (inputs) and what they experience (outputs), as assessed by animal-based measures, has received little attention. Procedural documents are commonly developed in the absence of empirical animal-based measures, creating uncertainty in animal welfare outcomes. Prescribed procedures are valuable as guidelines for standardising methodology, but the development of ‘welfare standards’ that focus on desired thresholds for animal-based measures offers many advantages for improving animal welfare. Refinement of the use of procedural documents in wildlife management is required to ensure they generate desirable outcomes for animals, and do not preclude the development of improved methods.
Context. Feral horses are a growing problem in Australia, despite implementation of management strategies. The incidence of horse sightings and horse-associated vehicle collisions within the Tuan and Toolara State Forest (TTSF), a coniferous plantation in south-eastern Queensland, has increased in the past decade, indicating an increase in population and the necessity to undertake an accurate appraisal of population abundance.
Aim. To determine the feasibility of using dung counts, defecation and dung-decay rates to determine the distribution and abundance of feral horse population in a managed coniferous plantation where dense vegetation prohibits the use of visual-based animal detection methods.
Methods. Population distribution was assessed by dung count incorporated into a vehicle strip-transect survey on 582 km of forest tracks. Population abundance was estimated from dung density, the mean defecation frequency of feral horses, and the mean number of days required for dung to decay. Dung density was obtained from on-ground distance line-transect survey that sampled all representative plantation habitats and consisted of 111 transects totalling 44.3 km.
Key results. The strip-transect survey clearly showed that although feral horses were dispersed across the plantation, the distribution was uneven, with the central region of the plantation being the most heavily populated. The combination of dung counts, defecation rate (mean ± s.d., 7.97 ± 8.74) over 24 h and dung-decay rate (444 ± 150.7 days) provided an estimation of the density of feral horses in various habitats and indicated that the plantation was occupied by 1321 (95% CI 940–1965) horses, which corresponded to an average density of 1.8 horses km–2. The method clearly identified variations in horse abundance among the various habitats within the surveyed areas. Open habitats, created following harvesting, showed higher occurrence rates, whereas the habitats of mature forest were scantily occupied.
Key conclusions. Dung counts are a simple, effective and practical technique that can provide information on distribution and abundance of feral horse population in densely forested habitats where visual-based techniques are not applicable. However, unbiased and precise defecation and decay rates must be estimated.
Implications. The study validated the use of dung counts to provide information on feral horse distribution and abundance in densely forested environments where direct methods of census may be difficult to obtain. The methods are applicable to a range of ecosystems, but defecation and dung-decay rates must be determined separately for each ecosystem.
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