Top Predators Research Articles

Stable isotope ratios indicate trophic niche overlap in three sympatric delphinid species in the Eastern Ionian Sea

AbstractStudying the sympatric ecology of closely related marine top predator species is of interest both from an ecological and conservation standpoint, because it provides insights into ecosystem functioning, how such species avoid competitive exclusion, and how human stressors may impact these patterns. In this study, we examine the isotopic niche of three sympatric dolphin species that inhabit the eastern Ionian Sea: the common dolphin (Delphinus delphis), the striped dolphin (Stenella coeruleoalba), and the common bottlenose dolphin (Tursiops truncatus). We used carbon, nitrogen, and sulfur isotope ratios to construct three‐dimensional isotope niches and calculate niche sizes and their overlaps among the three species to study interspecific competition for resources. Common dolphin niche overlapped with that of the striped dolphin by 77%, suggesting potential resource competition between these two species. The niche overlap between striped/common dolphins and bottlenose dolphins was much lower (47%). Large differences in isotopic ratios were found between the bottlenose dolphins of the Ionian Sea and those of a largely isolated population in the adjacent semienclosed Gulf of Ambracia, further corroborating the previously documented isolation between the two populations.

Development of an assay for the detection of the federally threatened Florida eastern indigo snake (Drymarchon couperi) using soil eDNA

AbstractAccurate information on species range contraction is the cornerstone of effective biodiversity conservation. The eastern indigo snake (Drymarchon couperi) is an apex predator in Florida and, similar to many species native to Florida, is threatened by widespread habitat destruction. Environmental deoxyribonucleic acid (eDNA) monitoring of this elusive snake would provide a non‐invasive approach to improve our knowledge of the species' range and distribution. We designed and tested an eDNA assay that can detect the presence of D. couperi from soil samples from their natural scrub habitat in Florida. We validated our assay in silico, in vitro, and in situ. Furthermore, we investigated the influence of temperature and humidity on the degradation rate of eDNA over time. We successfully amplified the cytochrome b gene for D. couperi at concentrations as low as 3 × 10−3 ng/μL and successfully detected the presence of D. couperi in 2 of 30 in situ field soil samples. The degradation experiment resulted in detectable DNA for 10 days. Interestingly, temperature and humidity had no effect on the degradation rate of eDNA in our experimental conditions. This study provides support for soil eDNA applications to detect the presence of a federally threatened species in their natural environment bolstering our ability to monitor the conservation and management of imperiled species. Environmental DNA provides an additional conservation tool to quickly and effectively monitor species range shifts driven by multiple anthropogenic stressors to promote the persistence of imperiled species.

Linear infrastructure and associated wildlife accidents create an ecological trap for an apex predator and scavenger

Animals may fall into an ‘ecological trap’ when they select seemingly attractive habitats at the expense of their fitness. This maladaptive behavior is often the result of rapid, human-induced changes in their natal environment, such as the construction of energy and transportation infrastructure. We tested the ecological trap hypothesis regarding human-created linear infrastructure on a widely distributed apex predator and scavenger—the Golden Eagle (Aquila chrysaetos), whose range spans the entire Northern Hemisphere. Roads and railways offer novel and attractive feeding opportunities through traffic-induced mortality of other species, while powerline areas provide perching or nesting sites and scavenging opportunities from electrocuted or collision-killed birds. These conditions may have negative demographic consequences for eagles if these apparent opportunities turn into traps. Using step selection functions, we analyzed habitat selection of 74 GPS-tracked Golden Eagles (37 adults and 37 immatures) during eleven years in Fennoscandia. To assess habitat attractiveness, we used wildlife traffic accident statistics for dominant wild species, and to evaluate demographic consequences, we used mortality data from the GPS-tagged eagles. Our analysis revealed that eagles selected linear features such as roads, railways and powerlines at both the population and individual levels. Both adult and immature eagles consistently selected these features, and the strength of selection for linear features increased with age in immature eagles. The linear features however had 5.5 times higher mortality risk for eagles than other selected habitats indicating the presence of an ecological trap. We discuss the implications of these findings for the conservation and population ecology of apex predators and scavengers, as well as their potential demographic consequences. To mitigate this issue, we urgently recommend the removal of carcasses from roads and tracks to prevent ecological traps for raptors and scavenger species worldwide. Additionally, we advocate for the development of methods and strategies to reduce wildlife traffic accidents.

Increased pathogen exposure of a marine apex predator over three decades.

Environmental changes associated with global warming create new opportunities for pathogen and parasite transmission in Arctic wildlife. As an apex predator ranging over large, remote areas, changes in pathogens and parasites in polar bears are a useful indicator of changing transmission dynamics in Arctic ecosystems. We examined prevalence and risk factors associated with exposure to parasites and viral and bacterial pathogens in Chukchi Sea polar bears. Serum antibodies to six pathogens were detected and prevalence increased between 1987-1994 and 2008-2017 for five: Toxoplasma gondii, Neospora caninum, Francisella tularensis, Brucella abortus/suis, and canine distemper virus. Although bears have increased summer land use, this behavior was not associated with increased exposure. Higher prevalence of F. tularensis, Coxiella burnetii, and B. abortus/suis antibodies in females compared to males, however, could be associated with terrestrial denning. Exposure was related to diet for several pathogens indicating increased exposure in the food web. Elevated white blood cell counts suggest a possible immune response to some pathogens. Given that polar bears face multiple stressors in association with climate change and are a subsistence food, further work is warranted to screen for signs of disease.

Return of the Eurasian lynx: using local stakeholder knowledge and experiences to inform lynx conservation in the French Alps

Abstract Large carnivore conservation in human-dominated landscapes is a complex issue, often marked by the stark contrast between those who hold deep-rooted animosity towards these animals and those who welcome their presence. The survival of the Eurasian lynx Lynx lynx in Europe relies on effective coexistence with humans in multi-use areas. We explored the experiences and perceptions of local hunters and pastoralists regarding the return of the lynx to the Giffre Valley, France, and mapped lynx distribution based on the probability of site use while accounting for detection probability. We conducted in-depth interviews with 29 respondents to gather data on lynx sightings, rationale for hunting and pastoralism, and perceptions of lynxes. We found that 45% of respondents had detected lynxes in the last 40 years, with an estimated site use of 0.66 ± SE 0.33 over the last decade, indicating there was a 66% probability of lynxes using the sites during that time period. Our results suggest that hunting and pastoralism in the region are rooted in a desire to carry on local traditions and connect with the natural world. Respondents generally tolerated the presence of lynxes, perceiving few threats to their livelihoods and activities, and expressing a willingness to coexist peacefully. However, some identified future challenges that could arise with the return of large carnivores to the valley and highlighted scenarios that could lead to a decline in tolerance. This study emphasizes the valuable knowledge of local hunters and pastoralists and their potential role in lynx population monitoring and conservation. Integrating stakeholder values in decision-making processes is crucial for inclusive and sustainable responses to promote biodiversity.

Multiphasic movement and step-selection patterns of dispersed tigers in the central Indian landscape.

Large carnivores play a crucial role in the ecosystem, though their conservation needs a landscape-level approach due to their wide range of habitats and dispersal events. The study of tigers in a human-dominated landscape matrix and their adaptation and adjustment of movement behaviours during the dispersal phase is essential for long-term conservation planning and management policy. We studied the dispersal event of five VHF/GPS collared individuals during 2009-2020. We investigated movement parameters (step length), and the effects of anthropogenic pressures (distance from village), distance from water and vegetation cover, on behavioural phase under a Hidden Markov Model framework. We also tested the effects of distance from village, vegetation cover, and habitat types on animal movement using an integrated Step Selection Function framework. The mean step length (405.44±10.63 m/hr) varied widely by different time of day. Displacement was high during the night (665.28±21.36 m/hr) compared to day (434.16±17.37 m/hr). Tigers moved fast (872.7m; 95% CI 839.1-906.3m) with longer step length and a directional turning angle in non-forested areas (i.e. the human-dominated landscape), likely to avoid conflict with humans. Individuals distinctly exhibited two behavioural states: encamping (~32% of the time) and travelling (~68% of the time). Further, they avoided the human-dominated landscape and mostly remained in and forested areas, especially during nighttime. Our study is the first attempt to understand behavioural transition of dispersal tigers and their habitat selection. Lesser anthropogenic disturbance and high vegetation cover positively influenced the tiger dispersal, while water availability did not affect their state transitional probability. Additionally, dispersers showed high affinity towards forested land during nighttime for travelling.The findings of this study show the importance of functional corridors and stepping stones (mostly encamping areas), and also provide baseline knowledge for integrated landscape management planning and policymaking for the long-term survival of tigers in metapopulation framework.

High carnivore richness despite human pressure and prey depletion in the south-west of the Kavango–Zambezi Transfrontier Conservation Area

Abstract Transfrontier conservation landscapes, such as the Kavango–Zambezi Transfrontier Conservation Area (KAZA TCA) in southern Africa, play a crucial role in preserving global biodiversity and promoting the sustainable development of local communities. However, resources to facilitate management could become scarce across large areas, leading to difficulties in obtaining baseline ecological information. Consequently, in the absence of sustainable management vast landscapes may experience loss of wildlife species, which could destabilize ecosystems. This effect is particularly significant if the loss involves top predators. Hence, understanding carnivore distributions is critical to informing management. We conducted a mammal survey in the Ondjou Conservancy in Namibia, an 8,729 km2 understudied area in the south-west of the KAZA TCA. We analysed camera-trapping data from a 2,304 km2 grid and identified high carnivore richness (18 species) despite widespread human activity and prey depletion. Using a multi-species occupancy framework we found that carnivore occurrence increased with increasing distance from the main village and with closer proximity to the Nyae Nyae Conservancy neighbouring the KAZA TCA, which has large and diverse carnivore populations. Carnivore occurrence was higher when local prey richness was high. The Ondjou Conservancy could function as an important buffer for the larger conservation network, yet rural communities in this area require support for fostering human–wildlife coexistence. Additionally, restoring the natural prey base will be critical to ensuring the long-term viability of carnivore populations in this and other human-impacted landscapes. With many remote areas of transfrontier conservation landscapes being understudied, our findings illustrate the conservation potential of such areas within large-scale conservation networks.

The Effect of Climate Change on Indicator Wetland Insects: Predicting the Current and Future Distribution of Two Giant Water Bugs (Hemiptera: Belostomatidae) in South Korea.

Giant water bugs (Hemiptera: Belostomatidae) are top predators in wetland ecosystems, serving as biological indicators of the health of lentic ecosystems and as effective biological control agents for freshwater snails and mosquitoes. This study aimed to predict the current and future distribution of two Korean giant water bugs, Appasus japonicus and Diplonychus esakii, under three climate change scenarios, contributing to the sustainable management of wetland ecosystems in South Korea. Using MaxEnt models, we employed seven climatic and three non-climatic variables to investigate the habitat preferences and distribution patterns of the species. The results revealed that A. japonicus is likely to experience a northward range contraction due to climate change, while D. esakii is predicted to expand its distribution northward without losing its current range. These responses may lead to occupancy turnover between the two species, potentially driving reassembly in aquatic organism community. Elevation was the primary factor influencing the distribution of A. japonicus, whereas annual mean temperature was the most informative variable for D. esakii, both factors derived under the current climate conditions. These findings suggest that both species are highly sensitive to climate change, with potential range shifts toward higher latitudes and elevations. This study provides insights into how climate change could impact two giant water bugs, thereby supporting future efforts to manage and conserve wetland ecosystems in this country.

Consequences of terrestrial top predator control by Patagonian sheep farmers for coastal marine food webs

Most seabird species avoid predation by locating their breeding colonies in predator-free islands, inaccessible cliffs, capes, or on the mainland in Antarctica, the only continent without terrestrial predators. Departing from this general rule, a significant number of large Magellanic penguin (Spheniscus magellanicus) colonies exist nowadays in South American Atlantic mainland shores spanning a wide latitudinal range. Based on published radiocarbon dating of colonies, along with historical and archaeological records, we postulate that the current distribution of these colonies may be a response to predator eradication by sheep farmers. This would have made breeding habitats near marine food resources accessible and may have also reduced competition with neighboring colonies. We employed stable isotope analysis to estimate the penguin contribution to the diet of four pumas responsible for killing thousands of penguins in a breeding colony located within a coastal national park. Furthermore, we used a bioenergetic model to quantify the consumption of forage fish under different population distribution and abundance scenarios. We briefly discuss the implications of our results in the context of conservation policies aimed at establishing ecosystem baselines along the Patagonian shores.

Diversity, Composition and Distribution Patterns of Spiders (Arachnida: Araneae) in Sand Forest, South Africa

ABSTRACTSpiders are the dominant representative of the top predator guild in many terrestrial ecosystems, but their diversity and distribution in forests in South Africa are still understudied. This study aimed to determine ground‐dwelling spider diversity, composition and distribution patterns in both sand forest and savanna (and their ecotone) using pitfall traps and to provide a spider species checklist for these three habitats in Phinda Private Game Reserve. A total of 410 individuals from 64 species and 21 families were recorded from the three habitat types. The Lycosidae family and Pardosa crassipalpis were the most dominant family and species. Spider abundances were similar between sand forest and the ecotone, but lower in savanna. However, species richness was similar across habitats. Spider species assemblages were similar between sand forest and the ecotone, but differed from the species assemblages in savanna. Spiders play an important role in food webs both below‐ and aboveground. Therefore, determining their diversity and distribution contributes to the overall understanding of the ecosystem in addition to promoting conservation efforts of key habitats such as the critically endangered sand forest.

Ecosystem Sentinels as Early-Warning Indicators in the Anthropocene

We are already experiencing the rapid pace of environmental perturbation in the Anthropocene, necessitating the development of new tools and techniques for measuring changes in ecosystem dynamics. Sentinel species, from birds to invertebrates, have been used to provide insights into ecosystem function, as leading indicators of risk to human health and as harbingers of future change, with implications for ecosystem structure and function. Here, we offer an update to previous research identifying marine top predators as indicators of ecosystem shifts and examine terrestrial sentinels and the latest research on sentinels of pollution and human health. Using ecosystem sentinels enables rapid response and adaptation to ecosystem variability and environmental change in part because they may be easier to observe and in part because they may serve as leading indicators of ecosystem disruption. While there may not be a given taxon that is best suited as sentinels, we highlight how to select the most effective sentinels, including examples of when sentinel species have been incorporated into management. Choosing a suite of appropriate sentinels both will give insight into ecosystem processes and can help manage changing ecosystems into the future.

Native and non-native species response to the colonization and subsequent suppression of northern pike Esox lucius.

The expansion of northern Pike Esox lucius outside its native range into the western states of North America is a growing problem due to their negative effects on fish communities. Illegally introduced E. lucius were first detected in Box Canyon Reservoir in northeast Washington in 2004. By 2010, the E. lucius population was estimated at more than 10,000 individuals. Between 2012 and 2019, a gillnet suppression programme was conducted, which reduced the E. lucius catch per unit effort in Box Canyon Reservoir by 97% and their biomass by 98%. Between 2004 and 2019, four standardized surveys were conducted to characterize changes in the Box Canyon Reservoir fish community. Even after E. lucius were effectively suppressed, native species showed no signs of recovery during the study. The relative abundance of all native species decreased 82% in total number and 56% in total biomass between 2004 and 2019. Conversely, the relative abundance of non-native species increased 26% in total number and 33% in total biomass over the same period. As an apex predator, E. lucius had a significant impact on the fish community in Box Canyon Reservoir over a relatively short period of time (7 years), and appeared to act as a catalyst to increase the rate of replacement of native species with non-native species, which likely increased the pace of taxonomic homogenization in the reservoir.

Collaborative conservation for snow leopards: Lessons learned from successful community‐based interventions

AbstractCollaborative conservation interventions based on engagement with local communities are increasingly common, especially for large carnivores that negatively impact people's livelihoods and well‐being. However, evaluating the effectiveness of large‐scale community‐based conservation interventions is rarely done, making it problematic to assess or justify their impact. In our study focused on snow leopards (Panthera uncia) in five countries, we show that bespoke and well‐implemented community‐based and conflict management intervention efforts can lead to more sustainable conservation outcomes. Collaborative interventions, spread over about 88,000 km2 of snow leopard habitat, reduced livestock depredation and disease and associated economic costs. Additionally, they generated conservation‐linked livelihoods and enhanced community decision‐making, leading to more positive behavioral intent toward snow leopards and improved communities’ cooperation, economic security, and confidence. Our results provide lessons learned and recommendations for practitioners and governments to alleviate conflicts and foster coexistence with snow leopards and large carnivores more broadly. These include prioritizing locally led tailored solutions based on the PARTNERS principles, recognizing local community rights in conservation decision‐making, and recognizing the role of social norms in ensuring accountability.

Wolf and wild boar in the Alps: Trophic, temporal and spatial interactions in an Alpine protected area

In predator-prey systems, interspecific interactions at the spatial and temporal scale may affect different components of the ecosystem. Despite a growing interest in the topic, little is known about these interactions in many regions, particularly in areas recently recolonized by apex predators, such as the Alps. Using a multidimensional approach, we assessed wolf-wild boar interactions in a recently recolonized protected area of the Western Alps (Gran Paradiso National Park, Italy) by combining camera trapping and wolf scat analyses. First, we quantified the importance of wild boar in the wolf diet by comparing two different periods (October 2018–September 2020 vs. October 2021–September 2022). Second, we evaluated prey selection in 2021–2022, when data on prey availability were collected. Then, we assessed spatiotemporal interactions between the wild boar and the wolf. Finally, we calculated combined spatiotemporal associations between the wolf and the wild boar in comparison to other ungulate prey. We found a remarkable increase in wild boar consumption between the two periods; roe deer and wild boar were consumed in proportion to their availability, while the chamois was positively selected and the red deer and the ibex were less consumed in relation to their availability. Although we found no negative association between wolf and wild boar detection rates, in winter the wild boar limited its temporal overlap with the predator by being less active in sites more frequently used by the wolf, suggesting some spatial modulation of a temporal antipredator response. Among ungulate species, the wild boar had the highest combined spatiotemporal association with the wolf, particularly in autumn-winter. Our results suggest complex interspecific interactions in alpine areas recently recolonized by the wolf.

Avian and Mammalian Diversity and Abundance in Jhalana Reserve Forest, Jaipur, India.

We utilized camera traps to evaluate animal diversity, relative abundance, and the extent of anthropogenic activities in the Jhalana Reserve Forest (JRF), located in Jaipur, with a population of 3.9 million people. Between November 2017 and November 2019, camera traps were strategically deployed in the tourist zone and peripheral areas, capturing 16,328 photos. This study represents the first comprehensive baseline assessment of animal diversity in the JRF, documenting 39 species, including 18 bird species, 14 mammals, and 6 domestic species, alongside human activity. Among the 14 mammal species, 7 were carnivores. Notably, we identified 25 individual Indian leopards (Panthera pardus fusca) during 2017-2018, comprising 8 males and 17 females, highlighting the leopard as the apex predator in the JRF. Concurrently, domestic animals accompanied by humans were observed within the JRF. However, rigorous conservation efforts and patrols by the Rajasthan Forest Department resulted in a notable decline in human activity, from 28.04% in 2017-2018 to 3.92% in 2018-2019, with domestic animal activity reaching zero in the latter period. Consequently, the relative abundance of wildlife species increased during the study period of 2018-2019, underscoring the positive impact of conservation strategies implemented by authorities. Our findings establish that camera-trapping methodology collates definitive baseline data, assesses mammal diversity, and evaluates relative abundance in reserve forests within human-dominated landscapes. We strongly recommend a further study to assess the avifauna diversity. This study provides critical insights to inform the development and implementation of conservation strategies in similar protected areas.

Prey diversity in the deep ocean: metabarcoding feeding ecology of the commercially important queen snapper in the US Caribbean

The queen snapper, Etelis oculatus, is experiencing a growing fishery presence across the wider Caribbean, yet our understanding of its distribution, biology, and ecology remains limited. To address this gap, we investigated the feeding ecology of this demersal deep-water snapper using two molecular approaches: single-species barcoding and multispecies metabarcoding. Between November 2019 and July 2020, we collected 157 queen snapper from seven locations along the west coast of Puerto Rico. Our analysis identified a diverse array of prey items in the stomachs, comprising 61 species from 31 families, 18 orders, and 38 genera. Our findings suggest that E. oculatus is a large carnivore, primarily preying on squids, shrimps, and deep-water fishes. Notably, common fish prey included Diaphus brachycephalus, D. dumerilii, Dasyscopelus selenops, Coccorella atlantica, Sigmops elongatus, and Zaphotias pedaliotus. In contrast, prevalent invertebrate prey consisted of Abralia veranyi, Doryteuthis pealeii, Abralia redfieldi, Oplophorus gracilirostris, and Systellaspis debilis. Although our data suggest potential variation in diet composition across locations, definitive conclusions remain elusive. However, we observed heightened prey richness at seamount Pichincho, possibly attributable to the high structural complexity of the karst terrain on the seafloor. Additionally, we noted variation in prey species composition across size classes, with certain species more prevalent in larger or smaller queen snapper. Given the challenge of examining the prey of deep-water fish species, our study showcases the utility of both single-species barcoding and multispecies metabarcoding methodologies in characterizing the dietary range of queen snapper and similar demersal deep-water carnivorous fishes. The multispecies metabarcoding approach, in particular, offers a rapid, comprehensive, and effective means of identifying prey species. As the commercial value of the queen snapper continues to rise, our investigation into its feeding behavior provides critical baseline information for future species management efforts. By enhancing our understanding of its ecological dynamics, we aim to contribute to informed conservation and sustainable fisheries practices in the region.

Beyond yield: Unveiling farmer perceptions and needs regarding weed management in Bangladesh.

More than 3.5 billion people depend on rice for more than 20% of their daily calories. Globally, Bangladesh is the third largest rice producer. With 171 million people, Bangladesh is also among the top consumers. Local rice production not only affects the country's food security but also influences the global rice trade. A large yield gap has been reported due to weeds. Traditional hand weeding is very costly because of labor shortages resulting from industrialization. Limited data showed a higher yield and profits when using herbicides. However, quantitative data on various aspects of weed management and associated issues representing the country's variable rice ecosystem, which is characterized by 30 agroecological zones, are lacking. We collected data on weed management practices from 865 farmers and 69 agrochemical shops covering all 30 agro-ecological zones (AEZs) through a structured survey. We observed a significant regional variation among various parameters. Approximately 82% of farmers use herbicides, and few rely solely on either manual weeding or herbicides. Pre-emergence herbicides are the predominant. Application procedures are almost the same across the country. Although 40% of farmers had secondary and higher-level education, most depend upon local sellers' suggestions rather than reading the product label regarding the dose. Few farmers consider herbicides hazardous, and respondents rarely perceive any environmental impact. Pyrazosulfuron ethyl (35%) and acetochlor-containing bensulfuron methyl (27%) are the most-used chemical species. Approximately 45% of farmers observed that herbicides suppress early seedling growth. Additional fertilizer is required to compensate for this. Multiple weed species that are difficult to control through presently used herbicides were noted in all AEZs. Around 64% of farmers observed that herbicide application contributes to higher yields as a function of timely weeding. Cost comparisons showed that high labor prices will make rice cropping unprofitable in most parts of the country if herbicides are eliminated. Clear adverse effects of pre-emergence herbicides on early crop growth implied the potential benefits of broad-spectrum herbicide-tolerant genetically engineered (GE) rice to sustain the country's food security. Additionally, such GE rice could incentivize the adoption of alternate wet and dry irrigation methods, leading to water and cost savings.

Investigations on the Health Status and Infection Risk of Harbour Seals (Phoca vitulina) from Waters of the Lower Saxon Wadden Sea, Germany.

Harbour seals (Phoca vitulina) are the most common pinniped species in the Wadden Sea of Schleswig-Holstein, Hamburg and Lower Saxony, Germany. Their numbers have recovered after significant depletion due to viral outbreaks and effects of anthropogenic activities like pollution and habitat disturbance. Within the Wadden Sea National Park of Lower Saxony the harbour seal is protected. As a top predator in the Wadden Sea ecosystem, the harbour seal is a sentinel species for the state of the environment. Between 2015 and 2017, a total of 80 stranded dead harbour seals were collected along the coastline of Lower Saxony and submitted for pathological investigations. Of these, 70 seals were born in the same year (0-7 months, age group 1) and eight in the previous year (8-19 months, age group 2), due to high mortality rates in these age groups. However, two perennial animals were also available for examination during this period, one of which was in good nutritional condition. Many of the seals that had been mercy-killed and found dead were in poor nutritional status. Histopathological, microbiological, parasitological and virological examinations were conducted on 69 individuals (86% (69/80)) in a suitable state of preservation. Respiratory tract parasitosis, cachexia, and bronchopneumonia were the most common causes of death or disease. Overall, there was no evidence of a relapse of a viral disease outbreak. Macrowaste, such as plastic waste or fishery-related debris, were not found in any gastrointestinal tract of the animals examined. There was also no evidence of grey seal predation. Weakness and cachexia were prominent causes of disease and death in harbour seals found within a few weeks after birth, but bronchopneumonia and septicaemia also developed in slightly older animals. Frequently found microbial pathogens in seals from Lower Saxony were similar to those found in other studies on seals from the Wadden Sea region in Schleswig-Holstein, for example streptococci and Escherichia coli/v. haemolytica, Brucella spp. and Erysipelothrix rhusiopathiae, potentially human pathogenic germs. The results of the examinations of dead harbour seals from Lower Saxony show that pathological investigations on a representative number of animals deliver urgently needed information on the health status of the population. The results represent an important contribution to the state of the top predators of the Wadden Sea as part of the obligations within the Trilateral Wadden Sea Agreement, Oslo and Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR) and the Marine Framework Directive. The investigations should be continued as a matter of urgency and the stranding network should be expanded.

Short QT intervals in African lions.

The cardiac conduction system in large carnivores, such as the African lion (Panthera leo), represents a significant knowledge gap in both veterinary science and in cardiac electrophysiology. Short QT intervals have been reported from zoo-kept, anaesthetized lions, and our goal was to record the first ECGs from wild, conscious lions roaming freely, and compare them to zoo-kept lions under the hypothesis that short QT is unique to zoo-kept lions. Macroscopic and histological examinations were performed on heart tissue removed from nine healthy zoo lions. ECGs were recorded from the nine anaesthetized zoo-kept lions, and from 15 anaesthetized and conscious wild lions in Africa. Our histological and topographical description of the lion's heart matched what has previously been published. In conscious lions, the ECG recordings revealed a mean heart rate of 70±4beats/min, with faster heart rates during the night. PQ and QT intervals were heart rate dependent in the conscious lions. Interestingly, QT intervals recorded in wild lions were markedly longer than QT intervals from zoo lions (398±40 vs. 297±9ms, respectively; P<0.0001). Anaesthesia or heart rate did not account for this difference. We provide a comprehensive description of the cardiac anatomy and electrophysiology of wild and zoo-kept lions. QT intervals were significantly shorter in zoo lions, suggesting functional disparities in cardiac electrophysiology between wild and zoo-kept lions, potentially related to physical fitness. These findings underscore the plasticity of cardiac electrophysiology and may be of value when reintroducing endangered species into the wild and when managing lions in human care.

Carnivore exclosures to protect sheep affect the distribution of a wild cervid

With the recent recovery of large carnivores in Europe, preventive measures to protect livestock are on the rise. Fences that exclude carnivores from grazing areas have been proven as effective, but they can be costly as well as posing a barrier for wildlife. We studied the effect of exclosures of &gt; 10 km2 to protect sheep Ovis aries on the distribution and density of moose Alces alces using fecal pellet group counts in two study areas in southeastern Norway. During the summer grazing season, the fences were powered. Outside of the grazing season, one exclosure remained fenced while the other fence was demounted. This quasi‐experimental setting allowed us to investigate whether fences had a barrier effect for moose, and/or whether moose density was affected by interactions with sheep (competition or facilitation) or large carnivores (refuge hypothesis). During winter, moose pellet group density was about equal inside and outside of the exclosure with demounted wire strands, but less than half inside the permanently fenced exclosure compared to outside, indicating a potential fragmentation effect of the fence. During the grazing season, when wire strands were powered, moose pellet group density was equal or doubled inside as compared to outside both exclosures. Moose may have sought refuge from large carnivores inside the fences. Fecal pellet group densities of moose and sheep inside the fence were neither positively (facilitation) nor negatively (competition) correlated. However, moose used young forest, the most used habitat type by sheep, to a lesser extent inside than outside of the exclosures, maybe due to interference competition. Our study demonstrates that livestock protection fences can have an impact on more than the targeted wildlife species. To understand the mechanisms behind direct and indirect effects of fences, monitoring the movement and survival of individuals by means of GPS and camera traps would be needed.