Carnivore Guild Research Articles

Fear of the dark? A mesopredator mitigates large carnivore risk through nocturnality, but humans moderate the interaction

While constrained by endogenous rhythms, morphology and ecology, animals may still exhibit flexible activity patterns in response to risk. Temporal avoidance of interspecific aggression can enable access to resources without spatial exclusion. Apex predators, including humans, can affect mesopredator activity patterns. Human context might also modify temporal interactions between predators. We explored activity patterns, nocturnality and the effects of human activity upon a guild of carnivores (grey wolf, Canis lupus; Eurasian lynx, Lynx lynx; red fox, Vulpes vulpes) using travel routes in Plitvice Lakes National Park, Croatia. Humans were diurnal, foxes nocturnal and large carnivores active during the night, immediately after sunrise and before sunset. Carnivore activity patterns overlapped greatly and to a similar extent for all pairings. Activity curves followed expectations based on interspecific killing, with activity peaks coinciding where body size differences were small (wolf and lynx) but not when they were intermediate (foxes to large carnivores). Carnivore activity, particularly fox, overlapped much less with that of diurnal humans. Foxes responded to higher large carnivore activity by being more nocturnal. Low light levels likely provide safer conditions by reducing the visual detectability of mesopredators. The nocturnal effect of large carnivores was however moderated and reduced by human activity. This could perhaps be due to temporal shielding or interference with risk cues. Subtle temporal avoidance and nocturnality may enable mesopredators to cope with interspecific aggression at shared spatial resources. Higher human activity moderated the effects of top-down temporal suppression which could consequently affect the trophic interactions of mesopredators.Significance statementTemporal partitioning can provide an important mechanism for spatial resource access and species coexistence. Our findings show that carnivores partition the use of shared travel routes in time, using the cover of darkness to travel safely where their suppressors (large carnivores) are more active. We however observed fox nocturnality to be flexible, with responses depending on the activity levels but also the composition of apex predators. High human activity modified the top-down temporal suppression of mesopredators by large carnivores. The use of time by predators can have demographic and trophic consequences. Prey accessibility and susceptibility can be temporally variable. As such, the ecosystem services and the ecological roles of predators may be affected by human time use as well as that of intraguild competitors. Temporal interactions should not be overlooked when evaluating human use and conservation priorities in protected areas.

Choice of Hunting Method Influenced Human‐Carnivore Competition in Late Pleistocene Southeast Asia

Competition has been investigated as a source of dispersal pressure in animal species both past and present. Particularly in Southeast Asia, where the Pleistocene carnivore guild remains largely intact to this day, there is a unique opportunity to assess the effects of competition on both dietary and spatial (dispersal) niche partitioning behavior in humans. Here, we investigate the relationship of early modern humans to local carnivores during their likely period of dispersal through Laos and Vietnam (~80‐50ka) to – for the first time – assess humans as a member of a local carnivore guild. By using the Competition Index (CI), a method which has shown success in predicting competitive pressure in island Southeast Asian paleontological communities on a scale of 0 (no competition) to 1 (full prey overlap, maximum competition). We approach this research with a purposeful desire to remove the “bias of human exceptionalism” from our analysis, treating humans as another medium size animal. We find that humans definitively were subject to competitive pressure from concurrent carnivores, particularly medium‐size prey specialists like hyenas, dholes, and leopards (Max CI: 0.6, 0.5, 0.66 respectively). Additionally, we find that the estimated competitive pressure on humans changes accounting for hunting method (solo ambush vs. group hunting), with group hunting practices reducing competitive pressure for medium‐size prey, particularly from leopards. We suggest that hunting behavior may have been used along with dietary and spatial partitioning as a strategy to reduce competitive pressure during initial human dispersal in Southeast Asia and that biotic interactions should not be overlooked in studies of human dispersal in this region.Support or Funding InformationFunding for this work was provided by: National Geographic Early Career Grant #EC‐378R‐18, Wenner‐Gren Foundation Dissertation Fieldwork Grant, UIUC Anthropology Department, UIUC Graduate College, The Explorer’s Club Exploration Fund, and the Beckman Institute CS/AI Award.

Do spotted hyaenas outcompete the big cats in a small, enclosed system in South Africa?

AbstractCarnivores are adapted to kill, meaning sympatric carnivores can have particularly aggressive and harmful competitive interactions. The co‐existence of multiple carnivores in an ecosystem could be restricted by their similarity in ecological niches (e.g. dietary overlap); however, high prey abundances could facilitate their co‐existence. Although the development of small, enclosed reserves (<400 km2) in South Africa has reduced human–carnivore conflict, these systems may increase the likelihood of carnivore intra‐guild competition due to the clumping of competing carnivores into these restricted spaces. Using carnivore scat and kill site analyses, we determined the dietary preferences and overlap of sympatric large carnivores in a small, enclosed reserve, Selati Game Reserve (Selati). Large carnivores in Selati (lions (Panthera leo), spotted hyaenas (Crocuta crocuta) and leopards (Panthera pardus)) preferentially selected for varying combinations of prey size classes. Lions selected for large prey, leopards selected for small prey and spotted hyaenas did not prefer any particular prey size. Additionally, lions had the largest dietary breadth and the diet of leopards and spotted hyaenas overlapped considerably. Coupled with high prey densities in Selati, the predation strategies of the large carnivores could be facilitating their co‐existence. On the other hand, the high degree of dietary overlap among large carnivores suggests that there is strong potential for exploitation competition, particularly between spotted hyaenas and leopards as their diet overlapped extensively (91% and 93% for prey species and size class, respectively). Although spotted hyaenas are potentially outcompeting leopards in Selati, lions were the most dominant large carnivore. Our study reiterates the complexity of carnivore guild interactions and emphasizes how these interactions are subject to variation due to site‐specific circumstances (e.g. composition of prey and carnivore populations). We therefore encourage site‐specific, multi‐carnivore research throughout protected areas in southern Africa.

Trophic rewilding presents regionally specific opportunities for mitigating climate change.

Large-bodied mammalian herbivores can influence processes that exacerbate or mitigate climate change. Herbivore impacts are, in turn, influenced by predators that place top-down forcing on prey species within a given body size range. Here, we explore how the functional composition of terrestrial large-herbivore and -carnivore guilds varies between three mammal distribution scenarios: Present-Natural, Current-Day and Extant-Native Trophic (ENT) Rewilding. Considering the effects of herbivore species weakly influenced by top-down forcing, we quantify the relative influence keystone large-herbivore guilds have on methane emissions, woody vegetation expansion, fire dynamics, large-seed dispersal, and nitrogen and phosphorus transport potential. We find strong regional differences in the number of herbivores under weak top-down regulation between our three scenarios, with important implications for how they will influence climate change relevant processes. Under the Present-Natural non-ruminant, megaherbivore, browsers were a particularly important guild across much of the world. Megaherbivore extinction and range contraction and the arrival of livestock mean large, ruminant, grazers have become more dominant. ENT Rewilding can restore the Afrotropics and the Indo-Malay realm to the Present-Natural benchmark, but causes top-down forcing of the largest herbivores to become commonplace elsewhere. ENT Rewilding will reduce methane emissions, but does not maximize natural climate solution potential. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.

Cheetah communication at scent-marking sites can be inhibited or delayed by predators

Scent-marking is a way for individuals to indirectly communicate; however, the information is not exclusive to a single species and can be informative to a whole community. Prey or competitively inferior species can use scent-marks from predators/dominant species to avoid interactions. Cheetahs are a subordinate member of the large carnivore guild in Africa, yet olfactory communication in this guild has yet to be explored. We explore whether intraguild or intraspecific communication is occurring at cheetah scent-marking sites as well as whether dominant predator avoidance by cheetah occurs in response to predator presence or predator scent-marking. We recorded cheetah behaviour with video recording camera traps at cheetah scent-marking sites where a ‘landscape of fear’ was provided through natural predator presence or manipulated cues of predator presence. We found that cheetah took longer to return to scent-marking sites when a lion or a leopard was the previous species to visit the site. Moreover, cheetah increased the amount of time that they spent sniffing at scent-marking sites when another predator, as opposed to a cheetah, was the previous visitor. Finally, we noted that females never visited a scent-marking site after a predator was present nor when a predators’ scent-mark was present. Our results demonstrate that cheetahs use scent-marking sites for intraspecific communication, but also obtain intraguild information at these sites. Dominant predators can inhibit or at least delay important intraspecific communication around estrous events that occurs between cheetah at scent-marking sites, a novel form of interference competition. Competition occurs between species, and dominant species deprive subordinate species from key resources. Individuals are able to avoid the cost of direct interactions with competitors by using cues (both direct and indirect) such as scents to assess such risks. Using video recording cameras at cheetah scent-marking sites, we provide novel insight into how dominant predator species shape cheetah behaviour through the use of avoidance by cheetah to the presence of dominant predators. Scent-marking sites are important to cheetah communication around reproduction opportunities and territory maintenance; however, dominant predator species’ cues blocked female reproductive signalling at the sites and delay male visitation. This serves as a novel form of interference competition for cheetah, but we suggest that cheetahs maintain communication through the use of multiple sites.

Ecological drivers of Mycobacterium avium subsp. paratuberculosis detection in mongoose (Herpestes ichneumon) using IS900 as proxy

Mycobacterium avium subsp. paratuberculosis (MAP) is the etiological agent of Johne’s disease or paratuberculosis, a chronic infection affecting domestic ruminants worldwide. Despite sporadic reports of MAP occurrence in non-ruminants, information on the risk factors predisposing for infection is still scarce and evidence of transmission paths linking the livestock-wildlife-environment interfaces also remains lacking. In this study, we predicted that environmental, host-related, land use and human driven disturbance factors would modulate carnivore exposure to MAP. To test these hypotheses, we performed a retrospective survey, based on microbiological and molecular methods, in mainland Portugal including five sympatric species from the Herpestidae, Canidae, Viverridae, and Mustelidae families (n = 202) and examined 16 variables as putative predictors of MAP occurrence. Molecular evidence of MAP using IS900 as proxy was demonstrated in 7.43% (95%CI: 4.55–11.9) of surveyed carnivores, the highest proportions being registered for red fox (Vulpes vulpes) (10%; 95%CI: 4.0–23) and Egyptian mongoose (Herpestes ichneumon) (6.0%; 95%CI: 3.2–11). We demonstrate that important species of the Mediterranean carnivore guild, such as stone marten (Martes foina) and common genet (Genetta genetta), may also be exposed to MAP, being this the first time that occurrence in genet is reported. The high proportion of DNA-positive specimens, concurrent with the apparent lack of gastro-enteric lesions and molecular confirmation of IS900 in feces, argue for the presence of subclinical carriers that occasionally shed bacteria, potentially aiding as source of infection to susceptible species and possibly contributing for environmental contamination. Achievement of MAP isolation would prove beyond any doubt that MAP is present in this wildlife population. Ecological modelling results suggested that the probability of MAP infection using IS900 as proxy in mongoose is positively associated with higher altitude and temperature stability, as well as with lower annual rainfall. Density of livestock farms was found not to be a significant predictor, which may indicate that the livestock-wildlife interface is probably not important as an infection route for mongoose.

Large carnivore extirpation linked to loss of overstory aspen in Yellowstone

The striping of bark on the lower portion of aspen trees (Populus tremuloides) by Rocky Mountain elk (Cervus canadensis), or “barking”, increases entry points for disease organisms such as wood-decaying fungi, thereby increasing aspen tree mortality from heart rot. We hypothesized that this has occurred in Yellowstone's northern range aspen stands as part of a trophic cascade and has contributed to the premature and widespread loss of overstory trees. To evaluate these potential effects, we randomly selected aspen stands along a 60-km traverse across the park's northern range. For overstory trees ≥15 cm in diameter at breast height (DBH) within these stands, which were accessible to elk, we measured the height of barking (as indicated by deeply furrowed/blackened bark) and the proportion of increment core lengths with heart rot. Sampled trees had an average barking height of 2.2 m and 93.8% of them had heart rot. In contrast, only 13.3% of aspen trees that had grown in an environment protected from elk had heart rot. Heart rot comprised 45.2% and 2.5% of increment core lengths for the elk-accessible and protected stands, respectively. Results support a multi-level trophic cascade, from predator-to-prey-to-plants-to-fungi, whereby an incomplete large carnivore guild, over a period of seven decades, allowed the widespread barking of aspen by elk to occur. This, in turn, may have increased the prevalence of heart rot and has contributed to an accelerated loss of overstory aspen across the northern range.

A new abelisaurid from the Huincul Formation (Cenomanian-Turonian; Upper Cretaceous) of Río Negro province, Argentina

The record of abelisaurids in South America, particularly Argentina is relatively abundant. However, abelisaurid diversity is far from being well-known. Huincul Formation has yielded diverse theropod remains, including the abelisaurids Ilokelesia and Skorpiovenator. The aim of the present contribution is to describe a new abelisaurid coming from the Upper Section of the Huincul Formation (Cretaceous; Cenomanian-Turonian) at the Violante Farm fossil site, Río Negro province, northern Patagonia, Argentina. The new taxon described in this contribution is represented by an incomplete specimen including well-preserved maxilla and dorsal vertebrae, and distorted pelvic girdle and caudal and sacral vertebrae. Its size, much smaller than large abelisaurids as Abelisaurus and Carnotaurus indicates that the new taxon probably occupied a different ecological niche within the carnivoran guild.

The first North American Propterodon (Hyaenodonta: Hyaenodontidae), a new species from the late Uintan of Utah.

The carnivorous mammalian fauna from the Uintan (late middle Eocene) of North America remains relatively poorly documented. This is unfortunate, as this is a critical interval in the transition from “creodont” to carnivoran dominated carnivore guilds. This study reports a new species from the Uinta Formation of the Uinta Basin, Utah, the first North American species of the otherwise Asian hyaenodont genus Propterodon. The new species, Propterodon witteri, represented by a dentary with M2-3 from the late Uintan Leota Quarry, is larger than the well-known P. morrisi and P. tongi and has a larger M3 talonid, but is otherwise very similar. A phylogenetic analysis of hyaenodont interrelationships recovers P. witteri as a hyaenodontine but is generally poorly resolved. A relationship between Hyaenodontinae and Oxyaenoides, recovered by many recent analyses, is not supported. Among the Asian species of Propterodon, P. pishigouensis is reidentified as a machaeroidine oxyaenid and recombined as Apataelurus pishigouensis new combination. Isphanatherium ferganensis may also represent an Asian machaeroidine. Identification of a North American species of Propterodon and an Asian Apataelurus increases the similarity of North American Uintan and Asian Irdinmanhan faunas and suggests that there was substantial exchange of carnivorous fauna during the late middle Eocene.

The possible role of predator-prey dynamics as an influence on early hominin use of burned landscapes.

Foraging in burned areas has been suggested to represent the earliest stage in the use and control of fire by early hominins. Recently burned areas offer immediate foraging benefits including increased search efficiency for high-ranked food items and decreased hunting opportunities for ambush predators. As such, they provide a triple-bonus (reduced risk from ambush, ease of terrestrial travel and higher foraging returns) for some primates. However, previous studies have not yet accounted for other types of predators e.g., coursing (endurance predators that can pursue prey over long distances) which were sympatric with hominins and may also have exploited these environments. Behavioral ecology studies on the use of burned landscapes by extant carnivores demonstrate that while some ambush predators avoid recently burned areas, coursing predators do take advantage of their immediate hunting opportunities. Research examining habitat selection by animals under the simultaneous threat of multiple predator species with different modes of hunting, and the diversity of Plio-Pleistocene carnivore guild is suggestive of two possible evolutionary scenarios in which hominins could either have selected or avoided burned areas (3-2 mya), based on whether ambush or coursing predators were perceived as presenting the greatest risk.

Borrowing from Peter to pay Paul: managing threatened predators of endangered and declining prey species.

Conservation policy and practice can sometimes run counter to their mutual aims of ensuring species survival. In Kenya, where threatened predators such as lion deplete endangered prey such as Grevy’s zebra, conservation practitioners seek to ensure species success through exclusive strategies of protection, population increase and preservation. We found strong selection for the endangered Grevy’s zebra by both lion and hyena on two small fenced conservancies in Kenya. Despite abundant diversity of available prey, Grevy’s zebra were selected disproportionately more than their availability, while other highly available species such as buffalo were avoided. Lions were therefore not alone in presenting a credible threat to Grevy’s zebra survival. Conservation practitioners must consider interlinked characteristics of prey selection, resource availability and quality, the interplay between carnivore guild members and landscape scale population trends performance in wildlife management decisions.

Restoring apex predators can reduce mesopredator abundances

The role that apex predators play in ecosystem functioning, disease regulation and biodiversity maintenance is increasingly debated. However, the positive impacts of their presence in terrestrial ecosystems, particularly in human-dominated landscapes, remain controversial. Limited experimental insights regarding the consequences of apex predator recoveries may be behind such controversy and may also impact on the social acceptability towards the recovery of these species. Using a quasi-experimental design and state-of-the-art density estimates, we show that mesopredator abundances were reduced after the restoration of an apex predator, with evidence of resonating positive impacts on lower trophic levels. Iberian lynx Lynx pardinus reintroduction was followed by the reduction of the abundance of mesocarnivores (red foxes Vulpes vulpes and Egyptian mongooses Herpestes ichneumon by ca. 80%) and the recovery of small game of high socio-economic value (European rabbits Oryctolagus cuniculus and red-legged partridges Alectoris rufa). The observed mesopredator reduction resulted in an estimated 55.6% less rabbit consumption for the entire carnivore guild. Our findings have important implications for the social acceptability of Iberian lynx reintroductions, which crucially depend on the perception of private land owners and managers. Under certain circumstances, restoring apex predators may provide a sustainable and ethically acceptable way to reduce mesopredator abundances.

Occurrence and intraguild interactions of mesocarnivores in the North Sahara Desert, southern Tunisia

Differential habitat use and intraguild competition are both thought to be important drivers of carnivore species distributions and abundance. To assess how habitat factors and interspecific interactions affect the structure of this widespread carnivore guild, we developed occupancy models for multi-scale habitat of the following three canids: African golden wolf (Canis lupaster), red fox (Vulpes vulpes) and fennec fox (Vulpes zerda) present in North Africa. Species occurrence records were obtained between January 2014 and January 2016 from 175 sites, covering the southern Tunisia. Occupancies were estimated to be 0.74 ± 0.07, 0.69 ± 0.09, and 0.18 ± 0.06, for red fox, African golden wolf and fennec fox, respectively. Our results showed that distribution constraints for these three canids tend to be linked to human factors, reptile densities and land cover. The co-occurrence models highlighted the interactions between canids. African golden wolf occurrence was unaffected by the presence of other carnivores. Red fox was strongly associated with the African golden wolf. Unlike the African golden wolf, red fox appeared to strongly influence fennec fox occupancy. This study could be valuable for assessing patterns of distribution and impacts of landscape change elsewhere in their ranges.

Niche overlap and dietary resource partitioning in an African large carnivore guild

AbstractUnderstanding and quantifying a large carnivores’ feeding behaviour is a key component in determining its functional significance in an ecosystem, both in terms of its top‐down influence on prey species, but also its relationships with sympatric carnivores. Dietary overlap is one of the numerous niche dimensions used to characterize resource partitioning and potential competition within a community. We characterize the diet, potential dietary niche overlap and prey preference of a large African carnivore guild on small fenced protected areas. To quantify the potential inter‐ and intraspecific foraging competition, we analysed 5,128 kills, representing 35 prey species made by African wild dogs Lycaon pictus (n = 553), cheetahs Acinonyx jubatus (1,427), lions Panthera leo (2,648) and leopards P. pardus (500). Our results show that large African carnivores in small protected areas are exposed to considerable overlap in dietary resource utilization. At the interspecific level, African wild dogs and cheetahs displayed the greatest vulnerability to potential dietary competition. Lions exhibited marked differences in prey preference, mass and species utilization compared to the other carnivores. African wild dogs and cheetah females with dependent offspring occupied the greatest potential for dietary competition within the large carnivore guild. Using a case study based on the preferred biomass of prey available, we estimate the sustainable density of large carnivores at a small fenced prospective African wild dog reintroduction site. African wild dogs displayed the lowest mean predicted density compared to all sympatric predators with an expected population size of 7 individuals. Our research highlights the need to assess the influence of competitive forces in structuring and restoring large predators to portions of their historical range by identifying species most vulnerable to a potential reintroduction attempt. In the absence of controlled experiments, elucidating the influences of exploitation competition is challenging, and only through manipulating sympatric species presence and densities can these complex interactions be fully understood.

Lynx eats cat: disease risk assessment during an Iberian lynx intraguild predation.

Lethal interactions between members of the carnivore guild are well represented in literature. In the Iberian lynx, interspecific killing (without prey consumption) of some mesocarnivores, such as the Egyptian mongoose, genet, and red fox, has been reported. Although vaguely documented, evidence suggests feral cats fall victim to interactions with this apex predator. Here, we describe the first documented case of interspecific killing and partial consumption of a feral cat by an adult male Iberian lynx reintroduced in Southwestern Spain. Ulterior analyses demonstrated that the victim was viremic to feline leukemia virus. To prevent the dissemination of the virus and a potential outbreak in the Iberian lynx population, control measures, including the clinical evaluation of the male Iberian lynx, and intensive monitoring were implemented in order to detect intraspecific interactions. After 3 weeks, the lynx was evaluated, presented good condition and resulted negative to both ELISA and RT-PCR. Thanks to the long-term monitoring, this case could be detected and measures to prevent an outbreak could be implemented.

What explains variation in the strength of behavioral responses to predation risk? A standardized test with large carnivore and ungulate guilds in three ecosystems

If access to food is affected by the risk of predation, then the number of individuals killed by predators is an incomplete measure of the limiting effect of predation. Nonetheless, it is often assumed that the costs of antipredator responses (risk effects) are either small enough to be ignored or positively correlated with direct predation, and thus unlikely to alter inferences based on predation rates. These assumptions are rarely tested. Here we studied five large carnivores and ten prey species in three Zambian ecosystems to test relationships between direct predation, antipredator vigilance and trade-offs with foraging. The presence of a predator caused vigilance to increase by a factor of 2.4, with substantial variation among prey species in the strength of this response. This was associated with a 28% decrease in the proportion of individuals foraging, a trade-off that was consistent across species. We detected no correlation between direct predation and the strength of antipredator responses, which undermines the gambit of ignoring risk effects. The strength of antipredator responses was uncorrelated with broad attributes of predators and environments, but was correlated with attributes of prey. Responses were stronger for small species and for browsers/mixed feeders relative to grazers. It has previously been noted that small ungulates face higher rates of direct predation. Building on this inference, our results suggest that carnivore loss/restoration will also have stronger behaviorally-mediated effects on small ungulates, particularly browsers and mixed feeders. If such species increase their representation where carnivores are depleted, then cascading effects on vegetation would be expected.

Mesocarnivore community structure under predator control: Unintended patterns in a conservation context.

Across the Mediterranean, conservation programmes often operate concomitantly with hunting interests within game-lands. Carnivore guilds lie at the interface between contrasting management goals, being simultaneously fundamental components of ecosystems and targets of predator control to reduce predation on game species. Here, we evaluate the composition and spatial structure of a mesocarnivore community in a protected area of Southeast Portugal, with high economic investment in conservation and significant hunting activity. Between June and August 2015, we deployed 77 camera-traps across a ~80 km2 area. We report on interspecific disparities in mesocarnivore occupancy and associated environmental determinants. Contrasting occupancy states suggest an unbalanced community, biased towards the widespread occurrence of the red fox Vulpes vulpes () compared to other species (stone marten Martes foina, European badger Meles meles, Egyptian mongoose Herpestes ichneumon, common genet Genetta genetta, and Eurasian otter Lutra lutra) exhibiting spatially-restricted occupancy patterns (). The feral cat Felis silvestris catus was the exception () and, together with the stone marten, exhibited a positive association with human settlements. These findings are consistent with theoretical predictions on how mesocarnivore communities are shaped by the effects of non-selective predator control, paradoxically favouring species with higher population growth rates and dispersal abilities, such as the red fox. Our results reinforce the need to understand the role of predator control as a community structuring agent with potential unintended effects, while exposing issues hindering such attempts, namely non-selective illegal killing or biased/concealed information on legal control measures.

Coexistence of two sympatric flagship carnivores in the human-dominated forest landscapes of Northeast Asia

Understanding how large carnivore guilds survive in human-dominated landscapes is key to inform strategies for their conservation in the face of global carnivore declines. Amur tigers and leopards are recovering across the China-Russia border. However, knowledge is limited about competitive interactions between two large cats in Northeast Asia. To assess the spatial, temporal and combined spatiotemporal behavioral mechanisms potentially allow co-occurrence between tigers and leopards in a human-dominated forest landscape. Based on a large-scale camera-trapping data set in Northeast China, we used three different approaches for quantifying spatiotemporal associations: one spatial method (two-species occupancy model), one strictly temporal method (activity pattern overlap), and one spatiotemporal method based on multi-response permutation procedures at shared camera trap sites. Spatially, leopards showed no avoidance of the areas highly used by dominant tigers, but their diurnal activity pattern was significantly different from that of tigers. Spatiotemporal overlap analysis showed fine-scale behavioral avoidance when both co-occurred at camera locations, which further facilitates sympatry. Tigers spatially overlapped with humans, but they were less active during the day when human activities were more frequent. In areas with high cattle density, low occurrence of tigers and leopards may reflect the absence of sika deer, an important prey item for both species. This study provides the first empirical evidence that tigers do not limit leopard distributions, at least in our study area in Northeast Asia. Our results highlighted temporal segregation, not large-scaled spatial avoidance, as a key mechanism promoting coexistence of two large carnivores. Understanding these fine- spatial scale (i.e., camera locations) interactions between sympatric carnivores can help devise management strategies for predator guilds in human-dominated landscapes, currently a major global challenge.

Is there anybody out there? Occupancy of the carnivore guild in a temperate archipelago

Carnivores are important components of ecological communities with wide-ranging effects that vary with carnivore size, natural history, and hunting tactics. Researchers and managers should strive to understand both the presence and distribution of carnivores within their local environment. We studied the carnivore guild in the Apostle Islands, where the distribution and occupancy of carnivores was largely unknown. We monitored 19 islands with 160 functioning camera traps from 2014–2017, from which we collected 203,385 photographs across 49,280 trap nights. We documented 7,291 total wildlife events with 1,970 carnivore events, and detected 10 of the 12 terrestrial carnivores found in Wisconsin. Detection rates for species were generally higher in summer than winter, except for coyotes (Canis latrans) and red foxes (Vulpes vulpes). Finitesample occupancy estimates for carnivores varied across islands, with mean estimated occupancy across islands varying from a high of 0.73 for black bears to a low of 0.21 for gray wolves. Of the potential island biogeography explanatory variables for carnivore occupancy we considered, island size was the most important, followed by distance to the mainland, and then interisland distance. We estimated that terrestrial carnivore species varied in the number of islands they were detected on from 1 island for gray wolves to 13 islands for black bears. Estimated carnivore richness across islands (i.e., the number of carnivores occupying an island) also varied substantively from 1 species on Michigan Island to 10 species on Stockton Island. Island size and connectivity between islands appear important for the persistence of the carnivore community in the Apostle Islands.

Can large carnivores change streams via a trophic cascade?

AbstractLarge carnivores were persecuted in Yellowstone National Park, WY, USA, during the late 1800s and early 1900s, leading to extirpation of grey wolves (Canis lupus) and cougars (Puma concolor). Soon thereafter increased herbivory of riparian plant communities by Rocky Mountain Elk (Cervus elaphus) became widespread in the park's northern ungulate winter range or “northern range.” Wolves were reintroduced in 1995–1996, again completing the park's large carnivore guild. In 2004 and 2017, we sampled Geyer willow (Salix geyeriana), a commonly occurring tall willow, along the West and East Forks of Blacktail Deer Creek in the central portion of the northern range. Results indicated high levels of elk herbivory in the 1990s, as in previous decades, not only continued to keep willows short, generally ≤52 cm in height, but also resulted in stream widening and incision, leading to “oversized” channel cross‐sections and a drastically reduced frequency of overbank flows. However, by 2017, willow heights ≥200 cm ( = 310 cm) were prevalent, and canopy cover over the stream, essentially absent in 1995, had increased to 43% and 93% along the West Fork and East Fork, respectively. These recent increases in tall willow heights, greater canopy cover, well‐vegetated streambanks, and the recent development of an inset floodplain all pointed towards a riparian/aquatic ecosystem beginning to recover. Overall, results were consistent with a landscape‐scale trophic cascade, whereby reintroduced wolves, operating in concert with other large carnivores, appear to have sufficiently reduced elk herbivory in riparian areas to initiate the recovery of Blacktail Deer Creek's riparian plant communities and stream channels.