The contamination status on persistent organic pollutants (POPs) in the Croatian terrestrial ecosystem was investigated by analyzing two classes of contaminants in adipose tissue of male European ...brown bear (Ursus arctos, N = 27) collected in 2021 and 2022. In addition to seven indicator polychlorinated biphenyls (PCBs), for the first time seven polybrominated diphenyl ethers (PBDEs) were analyzed in terrestrial species from this region. Sum of mass fractions detected in adipose tissue ranged from 0.011 to 0.463 ng g−1 lipid weight (lw) for the PBDEs, and from 0.652 to 30.17 ng g−1 lw for PCBs, with two orders of magnitude difference in the median value for these two groups of POPs (PBDEs: 0.022 ng g−1 lw; PCBs: 2.307 ng g−1 lw). PCBs dominated over PBDEs with a share of over 94 % of the total mass fractions of both groups of analyzed POPs. Results of the comparison of the PCB levels in the adipose tissue of brown bears reported here and in previous investigation from this region showed decrease in PCB-28, but increase of PCB-118 and PCB-180, while other congeners seemed to have reached a steady-state level in the environment over a ten-year period. Among the compounds analyzed in this study, BDE-47, PCB-153 and PCB-180 were the dominant congeners. Somewhat higher sum of PCBs was measured in April compared to October, although not statistically significant, indicating possible impact of winter hibernation causing concentration of lipophilic compounds due to body fat loss. Revealed POP levels in brown bears are consistent with the data on the low contamination of the Croatian terrestrial ecosystem in general.
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•PCBs dominated over PBDEs in adipose tissue of brown bears (>94 %).•BDE-47, PCB-153 and PCB-180 were predominant congeners in brown bears.•Higher PBDEs and PCBs were measured in bears after winter hibernation.•PCBs have reached a steady-state levels in the environment.•Revealed POP levels indicated low contamination of the Croatian terrestrial ecosystem.
This paper explores the relationship between different types of multilevel governance systems and policy coherence (i.e., uniformity of goals and rules) through a study of the governance systems for ...water and large carnivores in Sweden. The study objects represent multilevel governance systems for contested natural resources in the same national context, although in different policy areas and with substantial differences in institutional arrangements. We define the characteristics of each governance system through an institutional analysis of official records and compare their perceived ability to promote coherence through a statistical analysis of survey data. Our empirical results both support and problematize common ideas about how different institutional features relate to policy coherence in multilevel governance. The results clearly indicate that multilevel governance systems are challenged by conflicting goals and rules, both within and across governance systems, and that the capacity to address these difficulties is generally perceived as wanting in both types of systems. The results tentatively suggest that clashes with other governance systems are more prominent in polycentric and ecologically based systems, whereas internal goal and rule conflicts are more prevalent in centralized and more traditionally organized systems. The findings contribute to our understanding of the quandaries associated with the design of new governance systems. The study also contributes important insights into what features to focus on in attempts to mitigate the downsides of different institutional arrangements in multilevel governance systems.
International conservation efforts and prohibitionary drug intersect in unexpected ways throughout the Mesoamerican Biological Corridor (MBC). US-led counterdrug interdiction of transnational cocaine ...trafficking, or ‘narco-trafficking’, is increasingly pushing narco-traffickers and their associated environmental destruction into protected areas (PAs) to establish new smuggling routes. These locations are also where the greatest densities of jaguars (Panthera onca), an iconic and declining species, are found in Central America. Intersecting two geospatial datasets estimating 1) jaguar densities and 2) changes in landscape suitability for drug trafficking following counterdrug interdiction pressure, we estimated that roughly 69 % of the estimated population of jaguars in the MBC were found in areas of increased suitability for narco-traffickers. Moreover, jaguar populations within PAs were 2.5 and 34 times more likely to be in increased narco-trafficking suitability areas than those in jaguar corridors or other area without conservation designations, respectively. These findings illustrate the full costs of continuing current counterdrug interdiction policies alongside conventional conservation strategies and suggest that community-based conservation governance may more effectively discourage narco-trafficking activities and enhance conservation outcomes.
•Supply-side counterdrug interdiction pushes cocaine trafficking, or ‘narco-trafficking’, activities into remote areas•Jaguars in protected areas and corridors are at greater risk from clandestine activities than those in non-protected areas•Full accounting of collateral damages from U.S. drug policy would significantly raise the cost estimates of the War on Drugs•Renewed investment in community-based conservation approaches is an alterative to militarized drug control policy
Studies that focus on single predator-–prey interactions can be inadequate for understanding antipredator responses in multi-predator systems. Yet there is still a general lack of information about ...the strategies of prey to minimize predation risk from multiple predators at the landscape level. Here we examined the distribution of seven African ungulate species in the fenced Karongwe Game Reserve (KGR), South Africa, as a function of predation risk from all large carnivore species (lion, leopard, cheetah, African wild dog, and spotted hyena). Using observed kill data, we generated ungulate-specific predictions of relative predation risk and of riskiness of habitats. To determine how ungulates minimize predation risk at the landscape level, we explicitly tested five hypotheses consisting of strategies that reduce the probability of encountering predators, and the probability of being killed. All ungulate species avoided risky habitats, and most selected safer habitats, thus reducing their probability of being killed. To reduce the probability of encountering predators, most of the smaller prey species (impala, warthog, waterbuck, kudu) avoided the space use of all predators, while the larger species (wildebeest, zebra, giraffe) only avoided areas where lion and leopard space use were high. The strength of avoidance for the space use of predators generally did not correspond to the relative predation threat from those predators. Instead, ungulates used a simpler behavioral rule of avoiding the activity areas of sit-and-pursue predators (lion and leopard), but not those of cursorial predators (cheetah and African wild dog). In general, selection and avoidance of habitats was stronger than avoidance of the predator activity areas. We expect similar decision rules to drive the distribution pattern of ungulates in other African savannas and in other multi-predator systems, especially where predators differ in their hunting modes.
The mitigation of conflicts associated with large carnivore damage to livestock and agriculture is pivotal to their conservation. We evaluate current programs to compensate and prevent large ...carnivore damage in 27 European countries and the factors related to the economic costs of these programs. Overall, high compensation costs are associated with free-ranging livestock (68% of total costs) and with national economic wealth. Contrary to general belief, the return of large carnivores does not always translate into higher compensation costs. We identify a tendency towards prioritizing compensation over prevention; only a few wealthy countries pay the majority of the money allocated for prevention programs to adapt husbandry practices to the presence of large carnivores. We conclude that programs mainly focused on paying large compensation amounts will often fail to build tolerance towards predators. To mitigate conflicts and optimize the cost-effectiveness of publicly funded measures, responsible agencies should be proactive, focus on prevention-based policies and periodically evaluate the effectiveness of compensation and prevention programs in an adaptive manner. With this purpose and to identify further solutions for conflict mitigation, we call for a pan-European database of damage occurrence, management actions and associated costs.
•Wealthy countries tend to spend more to compensate large carnivore damage in Europe.•High compensation and prevention costs are associated with free-ranging livestock.•Large carnivores' return does not always translate into high compensation costs.•Only few European countries subsidize preventive measures on a regular basis.•Compensation alone will often fail to build tolerance towards predators.
Climate change is one of the major challenges to the current conservation of biodiversity. Here, by using the brown bear, Ursus arctos, in the southernmost limit of its global distribution as a model ...species, we assessed the impact of climate change on the species distribution in western Iran. The mountainous forests of Iran are inhabited by small and isolated populations of brown bears that are prone to extinction in the near future. We modeled the potential impact of climate change on brown bear distribution and habitat connectivity by the years 2050 and 2070 under four representative concentration pathways (RCPs) of two general circulation models (GCMs): BCC-CSM1–1 and MRI-CGCM3. Our projections revealed that the current species' range, which encompasses 6749.8 km2 (40.8%) of the landscape, will decline by 10% (2050: RCP2.6, MRI-CGCM3) to 45% (2070: RCP8.5, BCC-CSM1–1). About 1850 km2 (27.4%) of the current range is covered by a network of conservation (CAs) and no-hunting (NHAs) areas which are predicted to decline by 0.64% (2050: RCP2.6, MRI-CGCM3) to 15.56% (2070: RCP8.5, BCC-CSM1–1) due to climate change. The loss of suitable habitats falling within the network of CAs and NHAs is a conservation challenge for brown bears because it may lead to bears moving outside the CAs and NHAs and result in subsequent increases in the levels of bear–human conflict. Thus, re-evaluation of the network of CAs and NHAs, establishing more protected areas in suitable landscapes, and conserving vital linkages between habitat patches under future climate change scenarios are crucial strategies to conserve and manage endangered populations of the brown bear.
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•Climate change affects brown bear habitats at the southern limit of its global range.•Range shifts due to climate change can cause bears to move out of protected areas.•Climate change could exacerbate human-bear conflicts and bear mortalities.•Conserving landscape connectivity is a key strategy to protect brown bear populations.
Increasing habitat fragmentation leads to wild populations becoming small, isolated, and threatened by inbreeding depression. However, small populations may be able to purge recessive deleterious ...alleles as they become expressed in homozygotes, thus reducing inbreeding depression and increasing population viability. We used whole-genome sequences from 57 tigers to estimate individual inbreeding and mutation load in a small-isolated and two large-connected populations in India. As expected, the small-isolated population had substantially higher average genomic inbreeding (
= 0.57) than the large-connected (
= 0.35 and
= 0.46) populations. The small-isolated population had the lowest loss-of-function mutation load, likely due to purging of highly deleterious recessive mutations. The large populations had lower missense mutation loads than the small-isolated population, but were not identical, possibly due to different demographic histories. While the number of the loss-of-function alleles in the small-isolated population was lower, these alleles were at higher frequencies and homozygosity than in the large populations. Together, our data and analyses provide evidence of 1) high mutation load, 2) purging, and 3) the highest predicted inbreeding depression, despite purging, in the small-isolated population. Frequency distributions of damaging and neutral alleles uncover genomic evidence that purifying selection has removed part of the mutation load across Indian tiger populations. These results provide genomic evidence for purifying selection in both small and large populations, but also suggest that the remaining deleterious alleles may have inbreeding-associated fitness costs. We suggest that genetic rescue from sources selected based on genome-wide differentiation could offset any possible impacts of inbreeding depression.
Habitat selection is a multi-scale process driven by trade-offs between benefits, such as resource abundance, and disadvantages, such as the avoidance of risk. The latter includes human disturbances, ...to which large carnivores, with their large spatial requirements, are especially sensitive. We investigated the ecological processes underlying multi-scale habitat selection of a large carnivore, namely Eurasian lynx, across European landscapes characterized by different levels of human modification. Using a unique dataset of 125 lynx from 9 study sites across Europe, we compared used and available locations within landscape and home-range scales using a novel Mixed Effect randomForest approach, while considering environmental predictors as proxies for human disturbances and environmental resources. At the landscape scale, lynx avoided roads and human settlements, while at the home-range scale natural landscape features associated with shelter and prey abundance were more important. The results showed sex was of relatively low variable importance for lynx's general habitat selection behaviour. We found increasingly homogeneous responses across study sites with finer selection scales, suggesting that study site differences determined coarse selection, while utilization of resources at the finer selection scale was broadly universal. Thereby describing lynx's requirement, if not preference, for heterogeneous forests and shelter from human disturbances and implying that regional differences in coarse-scale selection are driven by availability rather than preference. These results provide crucial information for conserving this species in human-dominated landscapes, as well as for the first time, to our knowledge, generalising habitat selection behaviour of a large carnivore species at a continental scale.
Large carnivores, such as wolves and lynx, are strictly protected by law in most European countries. However, they are still vulnerable due to habitat loss and illegal hunting. The Bohemian Forest ...Ecosystem lynx population is exemplary as a reintroduced carnivore population in Central Europe. The population expanded rapidly after the reintroduction (phase I) but then declined and stagnated at a low population size (phase II). There is some evidence that illegal hunting might have caused this development, but reliable data on the intensity of illegal hunting is lacking, and hence long-term consequences for the population cannot be assessed. We used a spatially-explicit individual-based dispersal and population model to inversely fit mortality probabilities to long-term monitoring data; the model integrated both chance observations and telemetry data, and discriminated between baseline mortality, road mortality and added unknown mortality. During phase I, the estimated added unknown mortality ranged between 3 and 4%, with an extinction rate < 5%; during phase II, the estimated added unknown mortality reached 15–20%, which would prevent animals from colonizing new habitat patches. The probability of extinction in phase II ranged between 13 and 74%, thereby reaching a tipping point at which the additional unknown mortality of a few animals could drive the population to extinction. However, when we considered the national parks as fully protected, the extinction probability dropped to <1%. Based on our results, we conclude that the added unknown mortality is most likely explained by illegal hunting and therefore the highest priority for the conservation of the lynx population in the Bohemian Forest Ecosystem should be the prevention of illegal hunting in national parks and their immediate surroundings.
Reintroductions may produce populations that suffer from decreasing genetic diversity due to isolation, genetic drift and inbreeding if not assisted by careful management. To assess the genetic ...outcomes of reintroductions in large carnivores, we used the Eurasian lynx (Lynx lynx) as a case study, which was the subject of several reintroduction attempts over the last 50 years. Although some restocking actions initially appeared successful, lynx recovery has stagnated in recent years. To reveal potential genetic causes of slow lynx recovery in Europe, we examined genome-wide patterns of genetic diversity and inbreeding using single nucleotide polymorphisms (SNPs) in all six successfully reintroduced populations in central Europe, as well as twelve natural populations across Europe and Asia. All reintroduced populations showed lower genetic diversity and elevated levels of inbreeding compared to source and other natural populations. Recent inbreeding is prevalent in all reintroduced populations with varying degrees of severity; the most severe cases are those with the lowest number of founding individuals. Interestingly, we found evidence of lower genetic diversity and recent inbreeding in the source population for five reintroduced populations, begging the question if individuals taken from these source populations can safeguard sufficient genetic diversity for future reintroductions. Given the observed genetic consequences, we advocate for standardized regular genomic assessment of source and target populations as well as individuals prior to release. Our study provides compelling evidence for the serious consequences of founder population size on the genetic diversity of reintroduced large carnivore populations, which has broad implications for their conservation.
•A high number of genetically tested founders in large mammal reintroduction programs are essential.•Reintroduced Eurasian lynx populations across Central Europe exhibit genome wide diversity loss.•Several reintroduced populations suffer from considerable recent inbreeding (ROH analysis).•Urgent natural or human-mediated reconnection of reintroduced populations is essential.
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