Animal Conservation最新文献

Predator–prey relationships can influence community processes, and a rich prey spectrum is important to favour carnivore conservation, as well as to buffer single prey towards intensive predation. Antipredator behavioural responses can occur and can be dynamic in time and space, which may generate counter-responses in predators. However, data are scarce on their role in modulating carnivore diet and behaviour. Data are especially needed for European landscapes that are largely anthropized and have been recently recolonized by large carnivores. In a protected area in central Italy recently recolonized by the wolf and hosting a rich community of wild ungulates, we studied the interactions between this predator and three ungulate species. At the initial stage of wolf recovery, the fallow deer and the wild boar were the main prey, while the roe deer was a minor food item. Through camera-trapping and predator food habits, we assessed temporal changes in wolf–prey relationships throughout 5 years (2017–2022). Wolf detection rates were spatially associated with those of fallow deer and wild boar, but shrub cover was positively related to predator and negatively to prey, suggesting possible prey avoidance of sites with lower visibility and greater predation risk. Throughout the years, the fallow deer increased its diurnal activity, with a decreasing temporal overlap with the predator. The wolf showed crepuscular/nocturnal activity, with an increased synchronization with the wild boar, which replaced the fallow deer as first prey. No support for major spatiotemporal responses was reported for wild boar and roe deer. With the ongoing recovery of carnivores across Europe, conservation priorities may emphasize the need to maintain an efficient ecological role of predators. Our results support the role of antipredator responses in modulating predator behaviour and diet and emphasize the importance of a diverse spectrum of wild prey to ensure the conservation of the ecological role of carnivores.

Habitat loss, fragmentation, and degradation of habitats are among the most pervasive impacts on species persistence. Mammals may vary in their response to these impacts, both in abundance and in physiological parameters. Herein, we verified how habitat quality influenced the small mammal nutritional status and stress levels among five semi-deciduous forest remnants in the Brazilian Cerrado. To assess species' physiological responses, we used body condition as an indicator of nutritional status and neutrophil/lymphocyte (N/L) ratio as an indicator of chronic stress in Gracilinanus agilis and Rhipidomys macrurus. We sampled 264 animals belonging to the following species: G. agilis, Didelphis albiventris, Akodon montensis, Oligoryzomys spp., Rattus rattus, R. macrurus, Oecomys cleberi, Hylaeamys megacephalus, and three unidentified rodent species. We found no negative effect of reduced habitat quality on the body condition of G. agilis and R. macrurus, however, the N/L ratios of these species were lower only in high-quality habitats, demonstrating that this parameter is an accurate indicator of chronic stress. Based on preliminary analysis, we also reported an impoverished fauna, mainly dominated by generalist species, in low-quality habitats. Thus, we conclude that short-term reduction in habitat quality leads to increased stress levels, which can in turn lead to future population declines and culminate in biotic homogenization.

The need for effective conservation strategies to combat the ongoing biodiversity crisis is well recognised. Conservation translocations are an important and frequently used form of conservation management for species recovery. Despite this, the uncertainty prevalent throughout the translocation cycle often makes it challenging to determine whether translocations should be included in the suite of actions to achieve desired conservation outcomes. Further, the fundamental question of whether translocations should occur is seldom assessed as a formal decision. We applied a formal decision analysis for the conservation management of a highly threatened bird (karure | kakaruia | Chatham Island black robin | Petroica traversi) to evaluate whether translocation and/or other actions should be implemented for species recovery. The species' precarious status (<330 adults), combined with uncertainty about translocation outcomes, meant that for years, decision-makers were reluctant to act given the potentially severe consequences of translocation failure. We used structured decision-making in conjunction with population modelling to estimate the consequences of translocations and other actions across a range of objectives identified by Moriori and Ngāti Mutunga o Wharekauri (Indigenous Peoples of Rēkohu | Wharekauri | the Chatham Islands), the local community and government agencies. Structured decision-making facilitated an inclusive approach that ensured all participants were actively engaged in the decision-making process including the identification of the best management alternative while balancing multiple objectives. This process overcame the long-standing conservation impasse, resulting in rapid implementation of actions, including translocation, that would have otherwise been difficult to achieve. The preferred alternative across objectives involved multiple translocations, illustrating the vital role translocations have in the desired future management for the species. The methods used in our study can be readily applied in other species recovery programmes to help decision-makers navigate the complexities and uncertainties inherent in conservation decisions.

Over the past decade, the development of genetic and genomic tools for conservation management has come forward in leaps and bounds. Once considered a ‘nice to have’, genetic data are fast becoming an essential tool for informing and managing translocations. However, due to the complexity of the field, easily using genetic data for decision-making and monitoring remains beyond the reach of most managers and conservation biologists. In May 2020, we launched the Threatened Species Initiative (TSI), a programme designed to generate genomic resources for Australia's threatened species. Critical to the project is not only the generation of reference genomes and population genetic data but an online toolkit for conservation managers. The toolkit is a ‘one stop shop’ from collecting samples, to generating and analysing genetic data, to an easily interpretable genetic management report. A series of workflows and pipelines have been developed, including the TSI Biodiversity Portal, that uses point and click web interfaces to easily transfer raw sequence data and assemble genomes, transcriptomes and soon population genetics for management decisions. Here we present how the current toolkit works and provide case study examples for how it is being used to inform translocations and the management of threatened species.

In human-dominated landscapes, rebounding bear populations share space with people, which may lead to bear–human conflicts and, consequently, a decrease in acceptance and an increase in bear mortality linked to human causes. Previous analyses of brown bear (Ursus arctos) movement data have shown that bears adopt a security-food trade-off strategy in response to variable human-related risk. However, brown bear flexibility to cope with these risky situations may be reduced when resting, mating or stocking fat in preparation for hibernation. In this study, we measured the multi-scale spatial response of brown bears to human-related risk and food resource distribution in a highly heterogeneous human-dominated landscape. We examined habitat selection both within the population range (‘second-order’ selection) and at bedding site locations (‘third-order’) for GPS-tagged brown bears of a recently reintroduced population in the Italian Alps. We identified resting locations by field-validated spatio-temporal cluster analysis of telemetry locations. We mapped food availability and distribution using dynamic geographic layers of fruiting wild berries, and human-related risk using human mobility data (Strava-based Cumulated Outdoor activity Index). Brown bears appeared to compromise their need for food resources for avoidance of anthropogenic disturbance when selecting home ranges, as they utilized areas richer in wild berries less when human use of outdoor tracks was higher. Furthermore, selection of resting site locations strongly depended on the avoidance of human-related risk only, with less frequented, more concealed and inaccessible sites being selected. We conclude that humans compete for space with bears beyond their infrastructural impact, that is, by actively occupying key areas for bear survival, thereby potentially restricting the bears' realized niche. We propose mitigating actions to promote bear–human coexistence by selectively restricting human access to key areas during sensitive annual physiological phases for bear survival.

There is growing interest in working with beavers (Castor canadensis and Castor fiber) to restore and maintain ecosystem function, improve hydrologic conditions and build climate resiliency in freshwater ecosystems. Beaver translocation into historically occupied but degraded systems has been increasingly applied as a restoration practice over the last two decades. Knowledge of beaver distributions on the landscape is critical to understanding where and when beaver translocations may be effective. However, current understanding of beaver occupancy and translocation success is limited by uncertainty, subjectivity and inefficiency associated with available monitoring methods. We evaluated the efficacy and spatial inference associated with environmental DNA (eDNA) techniques for detecting beaver presence in natural wetland and stream systems in the Cascade mountains of Washington State. We conducted eDNA sampling paired with radio-tracking of translocated beavers at four relocation sites from October 2020 through October 2022 to elucidate spatial patterns of site use, eDNA detection probability and eDNA quantity. We found that eDNA techniques detected beaver rapidly over long distances – up to 2.9 km from known locations within the first week after release – and reliably detected beavers when they were upstream, with positive detections in 92.4% of downstream eDNA samples collected 1–3 months after release. We also found that eDNA quantity decreased with increasing distance from beaver and increased with the amount of upstream beaver activity. Our study suggests that eDNA is a sensitive tool for monitoring translocated beaver and can provide spatial information on beaver location and site use within a stream system. Hence, eDNA methods could be a valuable tool for rapid inventory and assessment of beaver occupancy and our findings highlight important implications for using eDNA to monitor other semi-aquatic mammal species that share similar life histories.

Accounting for uncertainty is essential for precautionary approaches to managing seabird bycatch in commercial fisheries. However, there is no existing mechanism to explicitly quantify the uncertainty of seabird-vessel interactions (i.e. co-occurrence in space and time). Here we develop a time geographic method to measure the probability of individual birds encountering (co-occurring within 30 km) and attending (within 5 km) individual fishing vessels. The approach involves creating voxel-based probabilistic space–time prisms (PSTPs) to model the movements of individual birds and vessels, with trajectory data from bird-borne GPS devices and vessel Automatic Identification Systems (AIS). We intersected these PSTPs to quantify the probability of interaction between bird-vessel pairs over time and space. We demonstrate the approach with a case study of interactions of Endangered Toroa (Antipodean Albatross; Diomedea antipodensis antipodensis) with pelagic longline vessels in part of the South Pacific high seas. We found 15 vessels within 150 km and 3 h of two birds, yet interaction occurred with only two of those vessels. We visualised the probability of encounter and attendance over time and space and determined that interactions lasted several hours each (up to 6.2–14.1 h attendance, 20.8–26.1 h encounter for one bird-vessel pair). Our time geographic approach adds to existing tools to quantify seabird bycatch risk by providing an explicit measure of uncertainty of seabird-vessel interactions. We provide a flexible methodological pathway and R scripts, the application of which would allow managers to estimate interaction probability for multiple marine species and fisheries, including those with lower-resolution positional datasets.