Carnivore Community Research Articles

Dietary partitioning of fishers and martens in a rapidly changing landscape

Niche partitioning is critical for the stable coexistence of competing species that share limited resources. Yet, niches are dynamic, especially in the face of rapid environmental change. Carnivores exhibit particularly strong forms of competition and are differentially affected by change. Fishers (Pekania pennanti) and martens (Martes caurina) are two species of carnivores that overlap in space, time, and resources. In the Sierra Nevada of California, these two species share habitats that are undergoing a sudden restructuring due to drought and the subsequent mortality of more than half of all trees. Using a long-term dataset from across the affected region of the Sierra Nevada, we quantified the diet, as well as dietary niche overlap and niche shift of fishers and martens during summer months before, during, and after these disturbances and as a function of spatial overlap. The summer diet of fishers and martens did not appear to be affected by change in live forest canopy and tree mortality. While fisher diet was unaffected by elevation, martens exhibited an increasing reliance on vertebrate prey at higher elevations. Our results suggest that during summer months the diet of fishers is highly diverse, even including fungi and insects, but the diet of martens is less diverse and more reliant on vertebrate prey. These different consumption patterns — which were largely unaffected by changing environmental conditions, except elevation — have led to unexpectedly low overlap in trophic niche space during the timeframe measured. Our findings demonstrate that the coexistence of martens and fishers regionally is likely facilitated, in part, through partitioning along the trophic niche axis. If drought conditions persist and lead to continued or increasingly reduced snowpack and altered vegetation, future research should assess how niche partitioning of fishers, martens, and other members of the broader carnivore community will endure.

The repatriation of wolves to Isle Royale alters the foraging of meso-carnivores

Abstract Due to the disproportionate role that large carnivores can have on communities and their global decline over the last century, carnivores are increasingly being repatriated across their historic ranges. The reintroduction of gray wolves (Canis lupus) can precipitate substantive changes to communities and ecosystems. Notably, wolves could have strong effects on smaller and subordinate carnivores, especially in altering their foraging behavior and prey selection. Past studies investigating wolf effects on other carnivores, however, have generally been conducted in relatively complex communities featuring a diverse assemblage of carnivores and prey and have lacked baseline (i.e., pre-repatriation) data. Consequently, researchers have quantified what a community looks like after wolf return, with little information on how the community behaved before. To better understand the effect of large carnivore repatriation on the foraging ecology of a carnivore community, we investigated the impact of reintroduced gray wolves on 2 meso-carnivores: Red Fox (Vulpes vulpes); and American Marten (Martes americana) within an insular and simple vertebrate community at Isle Royale National Park before and after wolf reintroduction. We analyzed >600 scats from 20 individual martens and 63 individual foxes as well as the stable isotopes of 9 and 22 tissue samples from martens and foxes, respectively, at both individual and population levels. We found that the wolf reintroduction had little effect on marten diet but strongly influenced fox diet depending on the analysis conducted. At the population level, our analysis revealed that both foxes and martens were dietary generalists consuming an array of food items including small prey, berries, and human food regardless of wolf presence. However, at the individual level, we found that prior to wolf repatriation foxes primarily consumed berries and small prey but following wolf repatriation the diet of foxes shifted to berries and human foods as well as large carrion. This post-wolf reintroduction shift in diet increased the dietary overlap between foxes and martens. Our work provides new insights into how the return of a large carnivore can alter the foraging ecology of small-bodied carnivores and act both to provision carrion resources as well drive other carnivores to consume more human food and increase dietary overlap.

Identifying Factors Mediating the Carnivore Richness–Productivity Relationship Across a Precipitation‐Driven Ecotone

ABSTRACTAimPrimary productivity is an important mechanism influencing the species richness of animal taxa such as mammals. However, the factors that mediate the relationship between carnivore species richness, for example, and productivity are not well understood. We examined whether the relationship between carnivore species richness and primary productivity followed a hump‐shaped relationship and explored potential pathways by which productivity influences carnivore communities.LocationWestern Great Basin, USA.MethodsWe deployed a camera‐trap grid across a strong precipitation—and the corresponding productivity—gradient and estimated carnivore species richness using a novel application of a multisession community occupancy model. To quantify the relationship between carnivore species richness and productivity, we included the linear and quadratic effects of average annual precipitation as covariates on carnivore species richness. We fit additional community models linking carnivore species richness to vegetation and land cover variables to identify factors that mediate the relationship between carnivore richness and productivity.ResultsThe linear effect of precipitation on carnivore richness was positive and the quadratic effect was negative, supporting the hump‐shaped relationship where richness declines at the highest levels of productivity. Similarly, carnivore species richness followed a quadratic relationship with vegetation height along the productivity gradient. The relationship between carnivore species richness and proportion tree cover was positive, with limited evidence that open vegetation types in the surrounding landscape increased site‐level richness.Main ConclusionsIn addition to supporting the notion that primary productivity has a strong and nonlinear influence on local‐scale carnivore species richness, our results suggest that vegetation structure may be an important mediator of this relationship. Although future changes in precipitation and productivity due to climate change are uncertain, our results indicate that targeting areas of intermediate productivity and vegetation height, such as woodlands, may be key for conserving species‐rich carnivore communities along productivity gradients.

Body size rules habitat selection and population declines after drought periods in a carnivore community of the Sahara Desert

Body size rules habitat selection and population declines after drought periods in a carnivore community of the Sahara Desert

Thin corridors limit wildlife: Variance of tropical carnivore distribution and habitat use in a critical rainforest corridor

AbstractMadagascar is acclaimed for its floral and faunal endemism and biodiversity. Among the island nation's most emblematic fauna are its native mammalian carnivores; they are members of the threatened and endemic Eupleridae family. The Corridor of Marojejy, Anjanaharibe‐Sud Special Reserve, Tsaratanana (COMATSA) is a newly protected corridor system that faces deforestation and lacks detailed assessments of its native carnivore community. We deployed 44 motion‐activated trail cameras to identify which terrestrial carnivores are found within the rainforest corridor landscape of COMATSA‐Sud and Marojejy National Park, and to examine carnivore occupancy, relative activity and the impacts of habitat edge. Our sampling array operated from October 20, 2021, to February 10, 2022 (113 days) and confirmed the presence of four species in Eupleridae: Cryptoprocta ferox, Fossa fossana, Galidia elegans, and Galidictis fasciata, as well as a non‐native carnivore species: Canis familiaris. We show that carnivore occurrences significantly increase with distance to forest edges. We discuss the negative impacts of forest loss on native carnivores and highlight the threats posed by the non‐native carnivore C. familiaris. Our findings spotlight faunal detections across the corridor and indicate that fewer native carnivores are found in the corridor compared to nearby protected areas, suggesting that deforestation correlates with a skewed distribution of carnivore detections. Based on our data, we provide management recommendations for the protection of the forest corridor and its endemic faunal community.

The pulsed effects of reintroducing wolves on the carnivore community of Isle Royale

Large carnivores are being globally reintroduced with the goal of restoring ecological interactions. However, the extent that competitive interactions are restored within communities is often unclear. In a before–after study within Isle Royale National Park (in the US state of Michigan), we quantified the spatial, behavioral, trophic, and demographic effects of the reintroduction of a large carnivore (gray wolf; Canis lupus) on meso‐carnivores (red fox; Vulpes vulpes) and small carnivores (American marten; Martes americana). The wolf reintroduction produced a phase‐dependent pulse perturbation: wolves constrained the distribution of foxes, thereby benefiting martens, yet foxes altered their behavior, notably using human‐provided resource subsidies (campsites and food) more frequently, which buffered demographic consequences. Once wolf packs coalesced, all observed changes subsided, and competitive interactions returned to their pre‐wolf values. Our results show that some predicted—and often desired—consequences of large carnivore reintroductions may not be permanent due to the transitory dynamics of social carnivores and the presence of humans, even within a “pristine wilderness”.

Beware of the stripes: Encounter between Lycalopex griseus and Conepatus chinga in their natural environment in central Chile

We document an occasional encounter between carnivore species Lycalopex griseus and Conepatus chinga, using camera traps in native Mediterranean forest of the Coast Range in central Chile. Photographic evidence is provided as to the agonistic behavior exhibited by C. chinga and the reaction of L. griseus to this interaction. In view of incomplete niche segregation and the spatiotemporal overlap in the habitat use for both species, our observations contribute to a better understanding of the interactions and ecological dynamics of the carnivore community of this ecosystem.

Human habitat modification, not apex scavenger decline, drives isotopic niche variation in a carnivore community.

Top carnivores can influence the structure of ecological communities, primarily through competition and predation; however, communities are also influenced by bottom-up forces such as anthropogenic habitat disturbance. Top carnivore declines will likely alter competitive dynamics within and amongst sympatric carnivore species. Increasing intraspecific competition is generally predicted to drive niche expansion and/or individual specialisation, while interspecific competition tends to constrain niches. Using stable isotope analysis of whiskers, we studied the effects of Tasmanian devil Sarcophilus harrisii declines upon the population- and individual-level isotopic niches of Tasmanian devils and sympatric spotted-tailed quolls Dasyurus maculatus subsp. maculatus. We investigated whether time since the onset of devil decline (a proxy for severity of decline) and landscape characteristics affected the isotopic niche breadth and overlap of devil and quoll populations. We quantified individual isotopic niche breadth for a subset of Tasmanian devils and spotted-tailed quolls and assessed whether between-site population niche variation was driven by individual-level specialisation. Tasmanian devils and spotted-tailed quolls demonstrated smaller population-level isotopic niche breadths with increasing human-modified habitat, while time since the onset of devil decline had no effect on population-level niche breadth or interspecific niche overlap. Individual isotopic niche breadths of Tasmanian devils and spotted-tailed quolls were narrower in human-modified landscapes, likely driving population isotopic niche contraction, however, the degree of individuals' specialisation relative to one another remained constant. Our results suggest that across varied landscapes, mammalian carnivore niches can be more sensitive to the bottom-up forces of anthropogenic habitat disturbance than to the top-down effects of top carnivore decline.

Size and shape heterodonty in the early Permian synapsid Mesenosaurus efremovi.

Paleozoic synapsids represent the first chapter in the evolution of this large clade that includes mammals. These fascinating terrestrial vertebrates were the first amniotes to successfully adapt to a wide range of feeding strategies, reflected by their varied dental morphologies. Evolution of the marginal dentition on the mammalian side of amniotes is characterized by strong, size and shape heterodonty, with the late Permian therapsids showing heterodonty with the presence of incisiform, caniniform, and multicuspid molariform dentition. Rarity of available specimens has previously prevented detailed studies of dental anatomy and evolution in the initial chapter of synapsid evolution, when synapsids were able to evolve dentition for insectivory, herbivory, and carnivory. Numerous teeth, jaw elements, and skulls of the hypercarnivorous varanopid Mesenosaurus efremovi have been recently discovered in the cave systems near Richards Spur, Oklahoma, permitting the first detailed investigation of the dental anatomy of a Paleozoic tetrapod using multiple approaches, including morphometric and histological analyses. As a distant stem mammal, Mesenosaurus is the first member of this large and successful clade to exhibit a type of dental heterodonty that combines size and morphological (shape) variation of the tooth crowns. Here we present the first evidence of functional differentiation in the dentition of this early synapsid, with three distinct dental regions having diverse morphologies and functions. The quality and quantity of preserved materials has allowed us to identify the orientation and curvature of the carinae (cutting edges), and the variation and distribution of the ziphodonty (serrations) along the carinae. The shape-related heterodonty seen in this taxon may have contributed to this taxon's ability to be a successful mid-sized predator in the taxonomically diverse community of early Permian carnivores, but may have also extended the ecological resilience of this clade of mid-sized predators across major faunal and environmental transitions.

A combined amplicon approach to nematode polyparasitism occurring in captive wild animals in southern China

BackgroundGastrointestinal tract (GIT) nematodes prefer to live in the intestines of wild animals, causing damage and even death, and posing a zoonotic risk. The polyparasitism of GIT nematodes results in the complex dynamics of the nematode communities that occur naturally in wild animals. However, the nematode community in captive wild animals is poorly understood.MethodsWe combined microscopic examination and amplicon sequencing for community diversity.ResultsWe characterized GIT nematode assemblages to one order, one family, four genera, and ten species, in 512 fecal samples of 121 species from captive wild animals in southern China. The positive rate of GIT nematodes was 20.7% (106/512), including 42.3% (11/26) in reptiles, 26.5% (39/147) in herbivores, 25.0% (25/100) in non-human primates, 20.0% (5/25) in omnivores, 12.2% (9/74) in carnivores, and 12.1% (17/140) in avians. The dominant nematodes were Haemonchus contortus in herbivores and Trichuris species in primates. The nematode communities of arboreal primates differed from their terrestrial counterparts, reflecting both host phylogeny and ecological constraints. Soil-transmitted Strongyloides species were widespread throughout the herbivore, primate, avian, and carnivore communities, and tended to infect omnivorous primates and terrestrial herbivores. In addition, new Trichuris and Heterakis species were found in the nematode communities of captive porcupines and peafowls.ConclusionThis study highlights the variation in the composition of the GIT nematode community and strengthens the attention to the harms induced by zoonotic nematodes and co-infective nematodes with low species richness.Graphical

Wolves recolonize novel ecosystems leading to novel interactions

Abstract The wolf (Canis lupus) is arguably the most successful species at recolonizing its now human‐dominated former ranges in Europe and North America. Over the centuries while the wolf was absent, humans have transformed ecosystems to a large extent. In this paper, we highlight key aspects of these human‐modified ecosystems that include changes to (meso)carnivore communities, wolves themselves (genetics, behaviour), woody plant communities and the playing field for predator–prey interactions (landscape structure). We argue that the recognition of the novelty of human‐modified ecosystems logically leads to novel pathways of how wolves can influence ecosystem functioning. Thus far, the ecological impacts of wolves in human‐dominated systems have largely been predicted based on the documented effects they have on prey species or lower trophic levels in well‐preserved systems with low human impact. However, wolves in human‐modified ecosystems will engage in an array of novel interactions and potential novel trophic cascades that do not occur in more natural ecosystems with lower human impact. This should encourage us to re‐assess the questions we ask about wolf impacts in novel systems. A promising direction for future studies is exploring what novel interactions establish and under what conditions wolves can exert their ecosystem impacts (context dependence) in the human‐modified ecosystems wolves are recolonizing. Policy implications. Understanding these novel interactions and the context dependence of ecosystem impacts could guide us to act to improve conditions to enable wolves to exert their ecosystem impacts again. These novel interactions may be the true ecological and societal value of having wolves returning to human‐modified landscapes.

Effects of burn severity and postfire salvage logging on carnivore communities in montane forests

Abstract Wildfire and postfire salvage logging are major drivers of forest succession in western North America. Although postfire landscapes support a variety of carnivore species, it is unclear how these animals respond to differing patterns and severities of burning, or to additional landscape change from postfire salvage logging. Open, early-seral habitats created by these disturbances are predicted to benefit generalists such as coyotes (Canis latrans) and weasels (Mustela spp.), but restrict the activity of forest specialists such as Canadaian Lynx (Lynx canadensis) and Pacific Marten (Martes caurina). We used winter track surveys, supplemented with remote cameras, to examine carnivore habitat use in and around large, mixed-severity burns in north-central Washington, United States (burned in 2006), and central British Columbia, Canada (burned in 2010, then partially salvage-logged; some areas reburned in 2017). At 10 to 13 years postfire, marten had similar detection rates across lightly and severely burned areas of the 2006 burn, as did coyotes. Marten selected lightly burned areas of the 2010 burn (6 to 9 years postfire) over higher burn severities, and selected burns over adjacent unburned forests. Weasels selected areas of higher burn severity on both landscapes, while Lynx selected lower burn severities. Weasels and coyotes selected areas with a greater proportion of salvage-logged habitat in the 2010 burn, while marten, lynx, and wolves (Canis lupus) avoided areas with salvage logging. Fishers (Pekania pennanti) showed no clear patterns of selection or avoidance in relation to burn severity or salvage logging. Burn severity strongly influences wildlife activity postfire; lightly burned residual habitats are critical for forest specialists. Postfire salvage logging alters carnivore communities and may hinder species that require structurally complex landscapes.

Time for a paradigm shift? Small carnivores' sensitivity highlights the importance of monitoring mid-rank predators in future global change studies.

Research Highlight: Jachowski, D. S., Marneweck, C. J., Olfenbuttel, C., & Harris, S. N. (2024). Support for the size-mediated sensitivity hypothesis within a diverse carnivore community. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.13916. A current paradigm in ecological research suggests that top predators are suitable sentinel species to identify ecosystem dysfunctions and monitor the effects of climate change. However, the adequacy of top predators to systematically take this function may be mistakenly inferred or unintentionally conflated from the fact that these species are regarded as biodiversity indicators or keystone, umbrella and flagship species in most ecosystems. Regarding terrestrial mammalian carnivores (order Carnivora), some researchers recently suggested that the smaller species likely possess a higher sensitivity to environmental changes than large carnivores because of their biological attributes and their intermediate position in food webs. To test this hypothesis, Jachowski etal. (2024) used camera trapping followed by occupancy and structural equation modelling to explore the dynamics of a diverse carnivore community and the factors that influence them. Their results confirmed that small carnivores are more sensitive to habitat changes and are interconnected by a greater number of significant pathways compared with larger carnivores. This support for the size-mediated sensitivity hypothesis strengthens the proposition that small carnivores (and other mid-rank predators) are ideal sentinel species for monitoring the effects of the wide range of contemporary and future environmental changes. Time will tell whether this new 'middle-out ecology' paradigm will be considered in future global change studies.

Increasing ambient temperatures trigger shifts in activity patterns and temporal partitioning in a large carnivore guild.

Shifts in species' interactions are implicated as an important proximate cause underpinning climate-change-related extinction. However, there is little empirical evidence on the pathways through which climate conditions, such as ambient temperature, impact community dynamics. The timing of activities is a widespread behavioural adaptation to environmental variability, and temporal partitioning is a key mechanism that facilitates coexistence, especially within large carnivore communities. We investigated temperature impacts on community dynamics through its influence on the diel activity of, and temporal partitioning amongst, four sympatric species of African large carnivores: lions (Panthera leo), leopards (Panthera pardus), cheetahs (Acinonyx jubatus) and African wild dogs (Lycaon pictus). Activity of all species was shaped by a combination of light availability and temperature, with most species becoming more nocturnal and decreasing activity levels with increasing temperatures. A nocturnal shift was most pronounced in cheetahs, the most diurnal species during median temperatures. This shift increased temporal overlap between cheetahs and other carnivore species by up to 15.92%, highlighting the importance of considering the responses of interacting sympatric species when inferring climate impacts on ecosystems. Our study provides evidence that temperature can significantly affect temporal partitioning within a carnivore guild by generating asymmetrical behavioural responses amongst functionally similar species.

Forest and snow rather than food or foe limit the distribution of a generalist mesocarnivore in winter

AbstractInvestigating species responses to trophic interactions and abiotic factors is crucial to better understanding their ecology and creating effective management strategies. In carnivore communities, smaller species are often regulated by larger ones via top‐down interference competition. Smaller subordinate carnivores can also be regulated by bottom‐up and abiotic factors, such as the availability of important prey, habitat features, and climatic conditions. However, substantial ambiguity remains regarding the relative roles these complex factors play in shaping subordinate carnivore populations, especially during winter. To investigate this issue, we conducted a large‐scale camera‐trapping study (n = 197 sites distributed across a ~60,000 km2 landscape) using a balanced study design that sampled a gradient of forest disturbance and climatic conditions. We used dynamic occupancy modeling to examine the influences of top‐down (interference competition), bottom‐up (prey and habitat), and abiotic (climate) factors on a widespread, generalist subordinate carnivore, the red fox (Vulpes vulpes), in Maine, USA. Across three winters, we collected 107 red fox and 185 coyote (Canis latrans) daily detections, and 3875 snowshoe hare (Lepus americanus) detections. We found evidence for the top‐down effects of coyotes on red fox detection probability and site colonization. However, contrary to theoretical expectations, the association between coyotes and red foxes was positive rather than negative. Snowshoe hares had a positive association with local extinction by red foxes, which also contrasts with prevailing theory given that snowshoe hares are an important winter prey of red foxes in this ecosystem. The intensity of forest disturbance and the proportion of conifer forest had negative effects on red fox occurrence and detection probability, while snow depth had a strong negative effect on site colonization. Together, these results suggest red foxes are limited more by abiotic and bottom‐up factors related to habitat than by the top‐down interference competition or primary prey availability in winter. Our study supports recent findings that bottom‐up factors may shape carnivore distributions during less productive times of year. Our work also highlights how caution is needed when extrapolating previous results from summer studies to winter, as the role of top‐down and bottom‐up factors may change seasonally.

Spatial heterogeneity facilitates coexistence between striped hyaenas and sympatric carnivores

AbstractAimInterspecific competition plays a key role in shaping carnivore communities. Top‐down effects can impact the coexistence of superordinate and subordinate competitors and prey across a shared landscape. Limited resources, their abundance and diminishing habitats can all exacerbate interspecific competition. Sometimes, behavioural mechanisms or adaptations are critical for subordinate carnivores to coexist with larger species. Here, we investigated the distribution pattern of the striped hyaena (Hyaena hyaena) population with respect to habitat features, sympatric carnivores and their prey species across a large landscape.LocationWestern and Eastern Ghats, India.TaxonStriped hyaena.MethodsWe collected presence–absence data for hyaenas, tigers, leopards, dholes and their prey using camera‐trapping and indirect sign surveys. Using a random forest algorithm, we modelled the local distribution of hyaenas as a function of important ecological variables, including climate, domestic prey abundance and the predicted probabilities of occurrence of other large carnivores and their prey.ResultsWe found that striped hyaenas were confined to relatively small, discrete areas compared to the three other predators, likely a mechanism for achieving coexistence in the landscape. Our empirical results suggested that hyaenas tend to avoid high occurrence probability areas of their co‐predators at a landscape level but foothold opportunities such as, arid climatic conditions, and prey abundance primarily determined spatial incumbency. Coexistence in an area with low to medium relative abundance of co‐predators offsets the interplay between carcass acquisition and risk associated. The coexistence of species was favoured by altitudinal heterogeneity probably providing denning refugia and also by their preference towards suboptimal thorn forests that sustain a low density of co‐predators.Main ConclusionsOur study showed a desisting impact of large predators on the distribution of the striped hyaena population. Furthermore, we suggest preventing habitat alteration in suboptimal habitats of large carnivores to facilitate coexistence in a shared landscape.

A shifting carnivore’s community: habitat modeling suggests increased overlap between the golden jackal and the Eurasian lynx in Europe

IntroductionThe European large carnivore community is recently showing positive trends. Beyond those, other species are expanding in Europe. In recent decades, the golden jackal (Canis aureus), a medium-sized canid, has rapidly expanded to western and northern Europe, after being historically confined to the Balkans. The Eurasian lynx (Lynx lynx), an apex predator once widely distributed throughout Europe, was nearly eradicated in the 19th century. Recent reintroductions, legal protection, and its natural expansion brought the lynx to recover, though some populations still face extinction. As the carnivores’ community across Europe is rearranging, ecological interactions are changing as well. Indeed, recent observations reported the golden jackal to kleptoparasitize the lynx. Our research aims to predict the potentially suitable habitats for the golden jackal and the Eurasian lynx, detailing the areas where those are expected to coexist soon.MethodsWe model their distribution in Europe for current and future scenarios, using both citizen-science and literature data, using the latter to buffer the possible biases of the former. For this aim, we included not only climatic variables, but also several biotic and abiotic predictors relevant to both species. Moreover, given his strong influence on the golden jackal, we compare our results with the predicted distribution of the grey wolf (Canis lupus).ResultsOur predictions show an increase in habitat suitability for the golden jackal, while an opposite trend is predicted for the Eurasian lynx. Also, we predict the target species to share a large portion of their range in the future, with most of these areas suitable for wolves, too.DiscussionOur results may have several impacts in the context of large-scale management, helping to predict further expansion of the golden jackal, and to identify critical areas for lynx conservation, supporting the management of possible reintroductions, also shedding light on the large carnivores’ changing community

Unclear relationships in interference competition among three sympatric medium-sized carnivores in a heavy snowy environment

Abstract Interference competition, a category of interspecific competition, is a critical aspect of understanding the dynamics of carnivore communities, as it can result in a decline in the health and reduced opportunity for resource acquisition of one or both competing species. Heavy snowfall environments during winter are expected to exacerbate interference competition due to decreased food resources and limited foraging opportunities caused by snow cover. However, knowledge on interference competition in such environments is limited. Using camera traps with baits, we evaluated the interference competition among three sympatric medium-sized carnivores, red foxes, raccoon dogs, and Japanese martens, within a heavy snowfall region of northeastern Japan. As in previous studies, we hypothesized that body weight would serve as a determining factor for superiority in winter snow environments. Diel activity patterns using the visitation time to baits did not reveal any clear differences. Nevertheless, the daytime occurrence frequency of Japanese martens during the snowfall season was higher than that of the other two species, indicating inferiority to the other species. The analysis of time intervals between species visiting baits revealed no clear superiority among the target species. These findings suggest that the interspecific relationships among medium-sized carnivores in winter snowy environments are complex and not easily determined.

Temporal partitioning and the potential for avoidance behaviour within South African carnivore communities.

Carnivora occupy many ecological niches fundamental to ecosystem functioning. Within this diverse order, carnivore species compete to establish dominance, ensure survival and maintain fitness. Subordinate carnivores must, therefore, adapt their behaviour to coexist with dominant species. One such strategy is the partitioning of temporal activity patterns. We aim to determine interspecific avoidance patterns among sympatric carnivores by examining coexistence along a temporal axis. We compared the temporal activity patterns of 13 carnivore species using multi-seasonal camera trapping data from four protected areas across South Africa: Associated Private Nature Reserves, Madikwe Game Reserve, Mountain Zebra National Park and Tswalu Kalahari Reserve. Interspecific coefficients of overlap in diel and core activity periods were calculated over the study period and during the wet and dry seasons. Furthermore, interspecific spatiotemporal behaviour was examined using time-to-event analyses. Our results showed that complete avoidance of diel activity patterns was rare among South African carnivore species. Most species were predominantly nocturnal and, therefore, diel activity overlap was high, whereas core activity overlap was significantly lower (p < .001). Diel activity overlap was significantly lower during the dry than wet seasons (p = .045). Lastly, evidence of spatiotemporal aggregation revolved around scavenging species. We show the importance of seasonality in the temporal avoidance behaviours of South African carnivores while highlighting the need for fine-scaled behavioural analyses. Overall, we show that the daily activity patterns of most subordinate South African carnivore species are not influenced by top-down forces in the form of competitional suppression and risk exerted by dominant species. If avoidance is required, it is more likely to manifest as fine-scaled avoidance of core activity periods. We suggest that the focus on core activity periods might be a more suitable tool for interspecific temporal partitioning research.

Direct and indirect landscape-scale pathways structure carnivore communities in an agro-prairie ecosystem

Abstract Many carnivore populations have experienced substantial declines and are at increased risk of extinction, mainly due to negative interactions with humans and biological traits that make them susceptible to habitat loss and fragmentation, often driven by agricultural expansion. Carnivore community richness is likely influenced by many direct and indirect factors, though it is unclear how carnivore communities are structured in prairie landscapes that are considered one of the most imperiled ecosystems worldwide. Our goal was to identify landscape-scale effects driving carnivore community richness in a contemporary agro-prairie ecosystem. We used 3 years of presence data (2018–2020) from camera-trap sites (n = 381) distributed across western Kansas, United States and developed a structural equation model (SEM) to test a priori hypotheses explaining carnivore richness. Measures of water availability, native prairie, and agriculture—as well as sampling effort (i.e., days cameras were active)—were all positively associated with carnivore richness. Additionally, our index of rabbit abundances at sites had a direct positive effect on our measure of carnivore richness. Our SEM explained 42% of the variance in carnivore richness (χ2 = 8.76, d.f. = 21, P = 0.99) in this human-dominated landscape. Our results suggest that carnivore communities in agro-prairie landscapes are structured through multiple direct and indirect landscape-scale pathways. Contemporary agro-prairie mosaics may act as filters for the agricultural tolerance of carnivores, with species more vulnerable to native prairie loss becoming locally extirpated.