Animal Conservation最新文献

We evaluate the frequency of flipper amputation and its impact on reproduction in the threatened loggerhead turtle (Caretta caretta) population of the Eastern Atlantic, through a long-term study on several high-density nesting beaches of Cabo Verde. 5982 adult females were individually identified, tagged and measured, and the presence of limb amputations was recorded. 918 of them had one or multiple amputations of the rear or front flippers. Most of these turtles (n = 778) had partial rather than complete flipper amputations. However, we found no difference in body condition indices (1.2 vs. 1.1), clutch size (82 vs. 83 eggs), or hatching success (79 vs. 80%) between amputated and non-amputated females. While amputations may cause individual mortality or reduced fitness, our results indicate that some amputated turtles successfully nest and survive across multiple nesting seasons. Moreover, the amputations do not appear to be impacting the strong recovery of this population. This study provides evidence of the successful reproductive capacity of amputated loggerhead sea turtles and, by extension, the potential reproductive success of amputees released from recovery centers.

Carnivores, especially wolves (Canis sp.), have profound impacts on their ecosystems, affecting the abundance and behavior of prey and competitors, but this has not been examined in detail for red wolves (C. rufus). We studied a population of red wolves that was reintroduced to eastern North Carolina in 1987 and initially thrived, peaking at 120 animals. Due to an increase in anthropogenic mortality and a decline in government support, the population experienced a crash starting in 2014. We evaluated changes in the relative abundance of prey and competitor species during the red wolf decline with 25 camera traps run primarily on National Wildlife Refuges from 2015 to 2021. If red wolves were having an ecological effect on the mammal community, we expected this effect would decline as the wolf population waned, resulting in increased prey and competitor populations. Supporting this, we found that relative abundance increased for most prey and competitor species including American black bear (Ursus americanus), bobcat (Lynx rufus), Virginia opossum (Didelphis virginiana) and Northern raccoon (Procyon lotor). For all species, this increase was most notable after spring 2018, the second year with low red wolf reproduction. For some species, the increase was dramatic; the detection rate for raccoon, bear and bobcat doubled from the spring of 2018 to the spring of 2021. White-tailed deer (Odocoileus virginianus) showed a general increase in relative abundance but remained prevalent even at their lowest detection rates. Our results lend correlational support to the hypothesis that red wolves had a strong effect on their ecosystems by suppressing prey and competitor populations when they were at their peak. This study adds to the growing body of evidence that reintroductions of large predators have ecological impacts, with the caveat that these impacts can decline rapidly if the predators dwindle back to critically low numbers.

Many threatened species require ongoing management, which is often funded through short project cycles. Evaluating whether the management is effective in protecting a species is important to inform future management investments. For migratory species, management may affect only part of a species' annual cycle, and reversing a population decline is challenging to achieve and demonstrate. Here, we evaluate whether conservation management projects funded by the European LIFE programme to safeguard a migratory vulture population achieved their major objective of stabilizing the target breeding population. Between 2012 and 2022, an international alliance of conservation organizations implemented multiple actions to reduce poisoning, direct persecution, and electrocution and collision with power lines along the Eastern Mediterranean flyway. We monitored breeding territories of the Balkan population of the globally endangered Egyptian Vulture Neophron percnopterus between 2006 and 2022, and tracked 60 young birds with GPS transmitters since 2010. We used these data to examine whether population growth rate and survival probability had increased since project implementation. The mean annual survival probability of adult territorial birds increased by 1.9% since 2014 from 0.937 to 0.955, and the monthly survival probability of wild juvenile birds increased by 9.7% from 0.833 to 0.914 since 2018. The population growth rate across the Balkans increased by 6.9% from 0.939 before 2018 to 1.005 since 2018. This indicates that the Egyptian Vulture population has remained stable for the past 5 years (2018–2022), but at a population size that is only half (105 adult territorial birds in 2022) than at the beginning of the time series (204 in 2006). We caution that ongoing management along the flyway and reinforcement are required to ensure that the Egyptian Vulture population on the Balkans can recover, but we show that flyway-scale collaboration of direct conservation actions can have lasting benefits for migratory species.

In order to make robust and feasible conservation plans, assessments of species' vulnerability or risk of extinction are ideally needed. However, there are wide differences in the criteria used to assess species vulnerability. Recently, a growing approach seeks to understand the patterns of biodiversity loss using life history traits because these traits show differential responses to environmental disturbances. In order to generate a functional vulnerability assessment for Mexican endemic amphibians, we integrated information from species distribution modeling, functional traits, and spatially explicit threats weighted differentially for each functional group. We obtained 124 distribution models evaluated by species, nine functional groups that represent the differential risk of species against anthropic threats, and 124 layers of spatial vulnerability. We found a generalized presence of threats to amphibians throughout the Mexican territory, highlighting the center of the country as the most affected area, while the southeast and north had a lower level of anthropic activity. We found differential vulnerability values in the distributions of Mexican endemic amphibians. In general, the anthropogenic impact on the distribution of Mexican endemic amphibians is high, and the percentage of habitat loss ranges from 51 to 97%, with an average of 83% lost to anthropogenic pressures. The functional group with the greatest loss of distributional area was found in the salamander genus Ambystoma, while functional groups 2 (frogs with arboreal habits, small size, and reproduction and development in bodies of water) and 4 (small or medium size frogs occupying terrestrial or riparian habitats with oviposition and development occurring in bodies of water or phytotelms) maintain the largest remaining suitable area after considering the threats. We present a replicable methodology that can be implemented anywhere, providing a new tool to generate specific layers that represent threats to functional groups. This allows for updated assessments of species distribution models that can be used in conservation planning, offering more robust data to make conservation planning decisions.

The hunter is the key actor in unsustainable hunting of bushmeat in African forests and his behavior is driven by socioeconomic factors among others. However, not much is known about the effectiveness of incentive-based conservation actions providing socioeconomic benefits to reduce hunting. This study, therefore, examined how changes in the socioeconomic situation of hunters brought about by reciprocal environmental agreements affects their hunting behavior. During a project implemented near the Dja Faunal Reserve (Cameroon), we recorded changes in socioeconomic characteristics of hunters for 15 months spanning 3 years. Bushmeat offtake and hunting effort parameters were also recorded. Comparisons of the evolution of these parameters over the years were made between hunters who signed the agreements and those who did not. We found that signatory hunters were older and had larger households than non-signatories, and they earned more income from cocoa sales. Although both groups of hunters had similar characteristics regarding hunting behavior at the start of the project, signatory hunters harvested less bushmeat at the end of project. More time was spent in hunting by non-signatory hunters compared to signatories who hunted less at the end of our monitoring period. Signatory hunters hunted less with firearms than non-signatories, and they consumed more and sold less of their catches compared to non-signatories. This study underlines the importance of reciprocal environmental agreements as an incentive-based conservation scheme that can reduce hunting pressure. These findings show that economic incentives provided to individuals through reciprocal environment agreements can promote livelihood paradigm shifts, alleviating poverty, decreasing dependence on natural resources and benefiting animal conservation.

Determining the abundance of cryptic carnivores is central to building successful conservation management to mitigate conflicts and support coexistence strategies. For these reasons, there is considerable investment in developing reliable, cost-effective tools for estimating the abundance of wildlife. Nevertheless, field-based comparisons of abundance methods remain uncommon, even while essential to refining methods and coming to consensus around best practices. Here, we compare two approaches still being tested in real-world application for an emblematic puma (Puma concolor) population in the Torres del Paine UNESCO Biosphere Reserve in southern Chile: (1) the unmarked estimator, space-to-event model (STE), which utilizes photographs gathered with camera traps, and (2) the genotype spatial partial identity model (gSPIM), which is an adaptation of the more established spatially explicit genetic capture-recapture method (SECR) based on genetic data extracted from scats collected in systematic surveys. We show the tremendous variation in resulting STE estimates depending upon the start time of the analysis and length of the sampling window, and showcase a refined iterative sampling approach in a Bayesian framework to both utilize the full camera data and to stabilize density estimates for a given sampling window. Across all sampling, estimates from the STE model ranged from 3.19 (1.6–5.1 representing 10th and 90th percentile of credible intervals) to 7.38 (3.3–11.6) independent pumas 100 km⁻². By comparison, our gSPIM model estimated 5.1 independent pumas 100 km⁻² (excluding kittens) (with credible intervals of 2.2–10.3). Neither method was compared with any known density to determine their accuracy. Nevertheless, we provide initial density estimates to guide conservation strategies for wildlife agencies and local communities overseeing and hosting nascent puma tourism and livestock ranching, as well as guidelines for the use of these methods for any wildlife species.

Illegal or poorly regulated wildlife trade may enhance parasite spread worldwide, leading to pathogen outbreaks and the emergence of diseases affecting native wildlife, domestic animals and humans. The order Psittaciformes has the largest proportion of endangered species among all birds worldwide and is one of the most trafficked taxa in the pet trade. However, despite the large number of parrot species commercialized worldwide, the influence of illegally traded wild birds on the introduction of exotic pathogens is still poorly investigated. Here we molecularly examined the prevalence and genetic diversity of haemosporidian parasites in illegally traded white-winged parakeets (Brotogeris versicolurus), one of the most trafficked parrots in South America. We found that 18.5% of parakeets harboured Plasmodium relictum GRW04, a highly invasive malaria parasite provoking population decline and even extinctions in native avifauna when established outside its natural range. We also showed that malaria infected birds have lower body condition than uninfected parakeets, revealing the negative effects of malaria on their avian hosts. These outcomes highlight the risk of malaria spill over and disease outbreak in illegally traded wildlife. Our results also reveal epidemiological key concepts in disease transmission, such as the role of poorly studied parrot species as natural reservoir hosts of haemosporidians. These findings stress the importance of enforcing health control regulations and trade policies to fight wildlife trafficking effectively.

The long-term conservation of species at risk relies on numerous, and often concurrent, management actions to support their recovery. Generally, these actions are habitat-based while others are focused on a species' position within its ecological community. Less studied are the impacts from human presence, despite evidence that human activity may reduce the area functionally available for occupancy or resource acquisition. In the winter of 2020/2021, COVID-19-related travel restrictions led to a reduction in helicopter-assisted back-country skiing (heli-skiing). We examined how these reductions in heli-skiing (termed the anthropause) affected the movement ecology and resource selection of southern mountain caribou (Rangifer tarandus caribou) as compared to two prior years (2018/2019 and 2019/2020) and the following year when heli-skiing resumed (2021/2022). We found that home-range size was on average 80–120% larger during the anthropause than in years of normal heli-ski operations. Movement rates also varied among periods, with movement during the anthropause (11.9 km²/day) being higher than in 2019/2020 (7.8 km²/day) and 2021/2022 (8.7 km²/day), though similar to 2018/2019 (12.2 km²/day). Resource selection among periods did not differ, with caribou consistently selecting old forests, high elevations and gentle terrain. These results suggest that back-country recreation, specifically heli-skiing, may be limiting access to resources for southern mountain caribou. This limitation arises through reduced home-range size within suitable late-winter habitat, relative to when heli-skiing is reduced or not occurring – consistent with Encounter Theory. While the demographic effects of reduced home-range size and movement were not examined here, reduced access to resources likely compounds other stressors known to affect population viability of caribou. The results of this study demonstrate the impact that recreation can have on wildlife and highlight the need to consider heli-skiing and other forms of recreation when developing recovery plans.