Asymmetrical intraguild interactions with coyotes,red foxes,and domestic dogs may contribute to competitive exclusion of declining gray foxes

Species coexistence is governed by availability of resources and intraguild interactions including strategies to reduce ecological overlap. Gray foxes are dietary generalist mesopredators expected to benefit from anthropogenic disturbance, but populations have declined across the midwestern USA, including severe local extirpation rates coinciding with high coyote and domestic dog occurrence and low red fox occurrence. We used data from a large‐scale camera trap survey in southern Illinois, USA to quantify intraguild spatial and temporal interactions among the canid guild including domestic dogs. We used a two‐species co‐occurrence model to make pairwise assessments of conditional occupancy and detection rates. We also estimated temporal activity overlap among species and fit a fixed‐effects hierarchical community occupancy model with the four canid species. We partitioned the posterior distributions to compare gray fox occupancy probabilities conditional on estimated state of combinations of other species to assess support for hypothesized interactions. We found no evidence of broadscale avoidance among native canids and conclude that spatial and temporal segregation were limited by ubiquitous human disturbance. Mean guild richness was two canid species at a site and gray fox occupancy was greater when any combination of sympatric canids was also present, setting the stage for competitive exclusion over time. Domestic dogs may amplify competitive interactions by increasing canid guild size to the detriment of gray foxes. Our results suggest that while human activities can benefit some mesopredators, other species such as gray foxes may serve as bellwethers for habitat degradation with trophic downgrading and continued anthropogenic homogenization.     

American marten and fisher do not segregate in space and time during winter in a mixed‐forest system

Understanding the mechanisms of coexistence between ecologically similar species is an important issue in ecology. Carnivore coexistence may be facilitated by spatial segregation, temporal avoidance, and differential habitat selection. American martens Martes americana and fishers Pekania pennanti are medium‐sized mustelids that occur sympatrically across portions of North America, yet mechanisms of coexistence between the two species are not fully understood. We assessed spatial and temporal partitioning in martens and fishers in the Upper Peninsula of Michigan, USA, using camera trap data collected during winter 2013–2015. To investigate spatial segregation, we used a dynamic occupancy model to estimate species’ occupancy probabilities and probabilities of persistence and colonization as a function of covariates and yearly occupancy probability for the other species. Temporal segregation was assessed by estimating diel activity overlap between species. We found weak evidence of spatial or temporal niche partitioning of martens and fishers. There was high overlap in forest cover selection, and both marten and fisher occupancy were positively correlated with deciduous forests (excluding aspen [Populus tremuloides]). There was strong temporal overlap (; CI = 0.79–0.82) with both species exhibiting largely crepuscular activity patterns. Co‐occurrence of martens and fishers appears to be facilitated by mechanisms not investigated in this study, such as partitioning of snow features or diet. Our results add additional insights into resource partitioning of mesocarnivores, but further research is required to enhance our understanding of mechanisms that facilitate marten and fisher coexistence.     

Competition and specialization in an African forest carnivore community

Globally, human activities have led to the impoverishment of species assemblages and the disruption of ecosystem function. Determining whether this poses a threat to future ecosystem stability necessitates a thorough understanding of mechanisms underpinning community assembly and niche selection. Here, we tested for niche segregation within an African small carnivore community in Kibale National Park, Uganda. We used occupancy modeling based on systematic camera trap surveys and fine‐scale habitat measures, to identify opposing preferences between closely related species (cats, genets, and mongooses). We modeled diel activity patterns using kernel density functions and calculated the overlap of activity periods between related species. We also used co‐occupancy modeling and activity overlap analyses to test whether African golden cats Caracal aurata influenced the smaller carnivores along the spatial and/or temporal axes. There was some evidence that related species segregated habitat and activity patterns. Specialization was particularly strong among forest species. The cats and genets partitioned habitat, while the mongooses partitioned both habitat and activity period. We found little evidence for interference competition between African golden cats and other small carnivores, although weak interference competition was suggested by lower detection probabilities of some species at stations where African golden cats were present. This suggests that community assembly and coexistence in this ecosystem are primarily driven by more complex processes. The studied carnivore community contains several forest specialists, which are typically more prone to localized extinction. Preserving the observed community assemblage will therefore require the maintenance of a large variety of habitats, with a particular focus on those required by the more specialized carnivores.     

Fine‐scale coexistence between Mediterranean mesocarnivores is mediated by spatial,temporal, and trophic resource partitioning

1. The partition of the ecological niche can enhance the coexistence of predators due to differences in how they exploit three main resources: food, space, and time, the latter being an axis that often remains unexplored.
2. We studied niche segregation in a Mediterranean mesocarnivore community composed by Vulpes vulpes, Genetta genetta, Meles meles, and Herpestes ichneumon, addressing simultaneously different niche axes: the temporal, trophic, and spatial axes.
3. We assessed temporal segregation between mesopredators and prey and between potential competitors, using camera trap data between 2018 and 2020 in a Mediterranean landscape in Southern Spain. We deployed camera traps in 35 stations in three sites with varying vegetation cover within Doñana National Park. We further examined the spatial overlap in activity centers and trophic preferences between potential competitors using diet information from studies performed in the study area.
4. We found an overall temporal segregation between trophic generalist species, with species showing higher temporal overlap differing in their trophic preferences and/or showing limited spatial overlap. Furthermore, we observed an overall high overlap between the activity patterns of predators and their major prey in the area (the common genet vs. small mammals and the red fox vs. European rabbit).
5. Our study suggests that coexistence of the different species that compose the mesocarnivore assemblage in Mediterranean landscapes can be facilitated by subtle differences along the three main niche axes, with temporal segregation being a most pronounced mechanism. Our findings reinforce the idea that the coexistence mechanisms underlying community structure are multidimensional.

     

Small cats in big trouble? Diet,activity, and habitat use of jungle cats and leopard cats in threatened dry deciduous forests,Cambodia

Dry deciduous dipterocarp forests (DDF) cover about 15%–20% of Southeast Asia and are the most threatened forest type in the region. The jungle cat (Felis chaus) is a DDF specialist that occurs only in small isolated populations in Southeast Asia. Despite being one of the rarest felids in the region, almost nothing is known about its ecology. We investigated the ecology of jungle cats and their resource partitioning with the more common leopard cats (Prionailurus bengalensis) in a DDF‐dominated landscape in Srepok Wildlife Sanctuary, Cambodia. We used camera‐trap data collected from 2009 to 2019 and DNA‐confirmed scats to determine the temporal, dietary and spatial overlap between jungle cats and leopard cats. The diet of jungle cats was relatively diverse and consisted of murids (56% biomass consumed), sciurids (15%), hares (Lepus peguensis; 12%), birds (8%), and reptiles (8%), whereas leopard cats had a narrower niche breadth and a diet dominated by smaller prey, primarily murids (73%). Nonetheless, dietary overlap was high because both felid species consumed predominantly small rodents. Both species were primarily nocturnal and had high temporal overlap. Two‐species occupancy modelling suggested jungle cats were restricted to DDF and had low occupancy, whereas leopard cats had higher occupancy and were habitat generalists. Our study confirmed that jungle cats are DDF specialists that likely persist in low numbers due to the harsh conditions of the dry season in this habitat, including annual fires and substantial decreases in small vertebrate prey. The lower occupancy and more diverse diet of jungle cats, together with the broader habitat use of leopard cats, likely facilitated the coexistence of these species. The low occupancy of jungle cats in DDF suggests that protection of large areas of DDF will be required for the long‐term conservation of this rare felid in Southeast Asia.     

长江源区同域分布兔狲、藏狐和赤狐的时空重叠度

兔狲(Otocolobus manul)、藏狐(Vulpes ferrilata)和赤狐(V. vulpes)是青藏高原三江源区域分布的重要小型食肉兽。本研究于2014年6月至2019年9月在青海省长江源区沱沱河和通天河沿岸选取208个位点布设红外相机, 通过所获取的时空分布数据比较了上述3种同域分布小型食肉兽的时空利用情况。通过空间重叠度系数的比较分析, 兔狲和藏狐、兔狲和赤狐以及藏狐和赤狐之间的空间重叠度系数分别为0.25、0.48和0.17, 这表明兔狲、藏狐和赤狐三者在空间利用上存在一定的差异。通过核密度估计方法分析, 兔狲和藏狐属典型的昼行性动物, 而赤狐以夜行性活动为主。兔狲、藏狐和赤狐每个物种在冷暖两季的日活动节律重叠指数分别为0.83、0.78和0.88。两两比较分析表明, 兔狲和藏狐二者的日活动节律重叠指数最高(0.84), 兔狲和赤狐在夜间活动时段存在一定重叠(0.63), 而藏狐和赤狐的时间生态位分化最明显, 重叠指数最低(0.48)。此外, 在暖季, 两两物种之间的日活动节律重叠指数均小于其冷季的重叠指数。综上所述, 长江源区兔狲、藏狐和赤狐3种小型食肉兽可通过空间和时间资源的利用差异来降低物种间的干扰和竞争, 从而达到同域物种共存的目的。     

Spatial and temporal overlap of caracal and serval in Serengeti National Park,Tanzania

Understanding activity and habitat use are important for identifying mechanisms facilitating species co-occurrence. We studied habitat use and activity patterns of caracals (Caracal caracal) and servals (Leptailurus serval), primarily nocturnal, mid-sized felids that prey extensively on small mammals and co-occur in portions of sub-Saharan Africa. Spatial and temporal patterns of segregation were investigated in a 1,085-km² area of Serengeti National Park, Tanzania from 2010–2012. We used occupancy analysis to quantify habitat use and kernel density estimators and Mardia–Watson–Wheleer tests to analyse activity patterns. We found evidence for habitat divergence but high temporal overlap between species. Servals selected for grassland and avoided shrubland and wooded grassland. In contrast, the findings showed that caracals avoided grassland and woodland–shrubland; however, 73% of caracals were detected in wooded grassland. Overall, caracals and servals co-occurred independently, Species Interaction Factor, (phi = 1). This indicates that differential use of habitats in part facilitated coexistence of caracals and servals. Proper management of the declining grasslands including other habitats are recommended to facilitate continued coexistence. Additional studies, including feeding ecology, would be important to further understand mechanisms facilitating coexistence between caracals and servals.     

Diets of sympatric native and introduced carnivores in the Barrington Tops,eastern Australia

Invasive predators have severe impacts on global biodiversity, and their effects in Australia have been more extreme than on any other continent. The spotted‐tailed quoll (Dasyurus maculatus), an endangered marsupial carnivore, coexists with three eutherian carnivores, the red fox (Vulpes vulpes), feral cat (Felis catus) and wild dog (Canis lupus ssp.) with which it did not coevolve. No previous study has investigated dietary overlap between quolls and the suite of three eutherian carnivores. By analysing scats, we aimed to quantify dietary overlap within this carnivore assemblage in eastern Australia, and to detect any differences that may facilitate coexistence. We also sought evidence of intraguild predation. Dietary overlap between predators was extensive, with the greatest similarity occurring between foxes and cats. However, some differences were apparent. For example, cats mainly consumed smaller prey, and wild dogs larger prey. Quolls showed greater dietary overlap with foxes and cats than with dogs. Intraguild predation was evident, with fox remains occurring in 3% of wild dog scats. Our results suggest wild dogs competitively dominate invasive foxes, which in turn are likely to compete with the endangered quoll.     

Peak hour in the bush: linear anthropogenic clearings funnel predator and prey species

Linear clearings, such as roads and tracks, are an obvious anthropogenic feature in many remote environments, even where infrastructure is sparse. Predator species have been shown to prefer moving down linear clearings, and therefore, clearings could increase predation risk for other species. We investigated whether tracks cleared for seismic surveys are preferentially used by predators and herbivores in a landscape inhabited by bilbies (Macrotis lagotis), a vulnerable species of conservation concern. We used a paired camera trap array to investigate the use of cleared seismic lines at four time points after clearing (1 month, 3 months, 7 months, 48 months) by six mammal species. Bilbies, cattle (Bos indicus/B. taurus), dingoes (Canis familiaris), feral cats (Felis catus) and agile wallabies (Macropus agilis) preferred to use seismic lines compared with adjacent undisturbed vegetation for almost all surveys, while spectacled hare wallabies (Lagorchestes conspicillatus) avoided them. Bilbies and agile wallabies showed similar temporal activity patterns on and off seismic lines but feral cats, dingoes and cattle used seismic lines at different times of day to control areas. We also investigated microhabitat selection by spool tracking individual bilbies. Bilbies selected a route through vegetation that was more open than surrounding vegetation. While spatial and temporal funnelling of bilbies and their predators (especially cats) may increase the frequency of encounter between the two, it is important to note that bilbies were active at significantly different times to predators both on and off seismic lines. The identified selection for seismic lines, and changes in spatial and temporal overlap between species, can be used to develop effective management strategies, to minimize potential impacts on native species.     

Jaguar and Puma Activity Patterns and Predator‐Prey Interactions in Four Brazilian Biomes

Jaguars (Panthera onca) and pumas (Puma concolor) coexist throughout the Neotropics. Using camera trapping in four Brazilian biomes, we compare the daily activity patterns of the jaguar and puma, and their relationships with their main prey species. We used a kernel density method to quantify daily activity patterns and to investigate overlap between these predators and their main prey. Both cats showed intensive nocturnal and crepuscular activity (0.69 and 0.14 kernel density, respectively, for jaguars; 0.68 and 0.19 kernel density, respectively, for pumas). Only in the Pantanal did we observe a pattern of concentrated diurnal activity for both species. We found little temporal segregation between jaguars and pumas, as they showed similar activity patterns with high coefficients of overlapping (average ?₁ = 0.86; SE = 0.15). We also observed a significant overlap between the activity patterns of the predators and their main prey species, suggesting that both predators adjust their activity to reduce their foraging energy expenditure. Our findings suggest that temporal partitioning is probably not a generalized mechanism of coexistence between jaguars and pumas; instead, the partitioning of habitat/space use and food resources may play a larger role in mediating top predator coexistence. Knowledge about these behavior aspects is crucial to elucidating the factors that enable coexistence of jaguars and pumas. Furthermore, an understanding of their respective activity periods is relevant to management and associated research efforts.     

Temporal resource partitioning mediates vertebrate coexistence at carcasses: The role of competitive and facilitative interactions

Unravelling how biodiversity is maintained despite species competition for shared resources has been a central question in community ecology, and is gaining relevance amidst the current biodiversity crisis. Yet, we have still a poor understanding of the mechanisms that regulate species coexistence and shape the structure of assemblages in highly competitive environments such as carrion pulsed resources. Here, we study how large vertebrates coexist in scavenger assemblages by adapting their diel activity at large ungulate carcasses in NW Spain. We used camera traps to record vertebrate scavengers consuming 34 carcasses of livestock and hunted wild ungulates, which allowed us to assess also differences regarding carcass origin. To evaluate temporal resource partition among species, we estimated the overlap of diel activity patterns and the mean times of each scavenger at carcasses. We recorded 16 species of scavengers, 7 mammals and 9 birds, and found similar richness at both types of carcasses. Birds and mammals showed contrasting diel activity patterns, with birds using carcasses during daytime (mean= 11:38 h) and mammals mostly at night (23:09 h). The unimodal activity patterns of scavengers showed asynchronous peaks among species. Subordinate species modified their activity patterns at carcasses used by apex species to reduce temporal overlap. Also, diel activity patterns of vultures closely followed those of corvids, suggesting facilitation processes in which corvids would enhance carcass detection by vultures. Two mammal species (12.5%) increased nocturnality at carcasses of hunted ungulates, which could be a response to human disturbance. Our results suggest that both temporal segregation and coupling mediate the coexistence of large vertebrates at carcasses. These mechanisms might lead to richer scavenger assemblages and thereby more efficient ones in driving critical ecosystem functions related to carrion consumption, such as energy and nutrient recycling and biodiversity maintenance.     

Neo-tropical felid activity patterns in relation to potential prey and intraguild competitors in the Calakmul Biosphere Reserve,Mexico

Predator behaviors influence, and are influenced by, prey and competitor behaviors. Jaguars (Panthera onca), pumas (Puma concolor), and ocelots (Leopardus pardalis) coexist throughout their geographic range as the three largest predators in a multi-predator community across diverse environments. This study tested for non-random segregation and overlap in the activity patterns of these felids and their shared prey in the southern buffer zone of the Calakmul Biosphere Reserve, in southern Mexico, using camera traps during February to August 2019. We detected little temporal segregation between the nocturnal activities of jaguars, pumas, and ocelots, although pumas were more active closer to dawn. Jaguars had low activity overlap with species likely to be common prey, whereas ocelots had high overlap with their potential prey. Pumas displayed finer-scale similarities in activity with species likely to be common prey. In an understudied area of conservation importance, this study shows that temporal segregation is an unlikely mechanism of coexistence. Further research should incorporate spatio-temporal avoidance and dietary differences to improve our understanding of the mechanisms that drive coexistence between generalist species in a diverse assemblage of threatened felids. Abstract in Spanish is available with online material.     

Direct evidence implicates feral cat predation as the primary cause of failure of a mammal reintroduction programme

As evidence mounts that the feral Cat (Felis catus) is a significant threat to endemic Australian biodiversity and impedes reintroduction attempts, uncertainty remains about the impact a residual population of cats following control will have on a mammal reintroduction programme. Also, behavioural interactions between cats and their prey continue to be an area of interest. Within the framework of an ecosystem restoration project, we tested the hypotheses that successful reintroductions of some medium‐sized mammals are possible in locations where feral cats are controlled (but not eradicated) in the absence of European Red Fox (Vulpes vulpes), and that hare‐wallabies that dispersed from their release area are more vulnerable to cat predation compared with those that remain at the release site. We used radiotelemetry to monitor the survivorship and dispersal of 16 Rufous Hare‐wallabies (Lagorchestes hirsutus spp.) and 18 Banded Hare‐wallabies (Lagostrophus fasciatus fasciatus) reintroduced to four sites within Shark Bay, Western Australia. Nearly all foxes were removed and feral cats were subject to ongoing control that kept their indices low relative to prerelease levels. All monitored hare‐wallabies were killed by cats within eight and 10 months following release. Significant predation by feral cats was not immediate: most kills occurred in clusters, with periods of several months where no mortalities occurred. Once a hare‐wallaby was killed, however, predation continued until each population was eliminated. Animals remaining near their release site survived longer than those that dispersed. The aetiology of predation events observed offers new insights into patterns of feral cat behaviour and mammal releases. We propose a hypothesis that these intense per capita predation events may reflect a targeted hunting behaviour in individual feral cats. Even where feral cats are controlled, the outcome from consistent predation events will result in reintroduction failures. Managers considering the reintroduction of medium‐sized mammals in the presence of feral cats should, irrespective of concurrent cat control, consider the low probability of success. We advocate alternative approaches to cat‐baiting alone for the recovery of cat‐vulnerable mammals such as hare‐wallabies.     

Disturbance‐driven variation in abundance–occupancy relationships over time in tropical forest fragments

A central problem in ecology is to understand spatial–temporal variation in abundance–occupancy relationship (AOR) and to identify the biological and anthropogenic drivers behind this variation. How AOR is influenced by ecological traits and anthropogenic disturbances is poorly understood. A data set of woody plants from eleven forest fragments around Kampala area, Uganda, recorded in 1990 and resampled in 2010 was used to analyse spatial variation in AORs at regional scales, variation between tree size classes and temporal change in these patterns. Slopes of the AORs for each forest were related to data on forest disturbances and effects of species traits on AOR at regional scales assessed. There were statistically significant positive interspecific AORs at regional scales. Over two decades, the strength of AOR and slopes increased at the regional scale. At local scale, slopes decreased, in correspondence with increasing disturbance. Species traits interacted with abundance to explain statistically significant variation in occupancy. Species successional status best explained occupancy variability. Incorporating species' traits and anthropogenic disturbance over time may lead to better understanding of the variation in interspecific AOR, and these results suggest that anthropogenic exploitation could be responsible for the changes in slope over time.     

Spatial and temporal distribution of tadpole assemblages (Amphibia,Anura) in a seasonal dry tropical forest of southeastern Brazil

We determined spatial and temporal distribution of tadpoles in 11 breeding habitats from Morro do Diabo State Park (MDSP), southeastern Brazil. Breeding habitats occupancy by tadpoles was tested to be different from a null model of random placement of species. We also tested whether tadpole occupancy in a given breeding habitat is organized according to different ecomorphological guilds, and we analyzed spatial partitioning of tadpoles among breeding habitats through similarity analysis. For temporal analysis we analyzed temporal partitioning of tadpole monthly occurrence also using similarity analysis, and assessed what climatic variable better predicts tadpole temporal occurrence in the MDSP, through regression analysis. Among tadpoles from 19 anuran species, distribution was different from a null model, but co-occurrence patterns among the breeding habitats did not differ among different guilds. However, breeding habitats with similar hydroperiods had similar species composition, which may be related to the reproduction patterns of species. Among the three climatic variables analyzed (rainfall, temperature, and photoperiod), temporal occurrence of monthly tadpole richness and abundance was correlated with temperature and rainfall. Most species were found only during the rainy season months, and overlap occurred within three groups of species. Thus, temporal distribution does not seem to be an important mechanism in species segregation at the MDSP, where the dry season is pronounced. In this case, spatial partitioning tends to be more important for species coexistence.     

Effects of Prey Presence and Scale on Bobcat Resource Selection during Winter

Factors relevant to resource selection in carnivores may vary across spatial and temporal scales, both in magnitude and rank. Understanding relationships among carnivore occupancy, prey presence, and habitat characteristics, as well as their interactions across multiple scales, is necessary to improve our understanding of resource selection and predict population changes. We used a multi-scale dynamic hierarchical co-occurrence model with camera data to study bobcat and snowshoe hare occupancy in the Upper Peninsula of Michigan during winter 2012–2013. Bobcat presence was influenced at the local scale by snowshoe hare presence, and by road density at the local and larger scale when hare were absent. Hare distribution was related primarily to vegetation cover types, and detectability varied in space and time. Bobcat occupancy dynamics were influenced by different factors depending on the spatial scale considered and the resource availability context. Moreover, considering observed co-occurrence, we suggest that bobcat presence had a greater effect on hare occupancy than hare presence on bobcat occupancy. Our results highlight the importance of studying carnivore distributions in the context of predator-prey relationships and its interactions with environmental covariates at multiple spatial scales. Our approach can be applied to other carnivore species to provide insights beneficial for management and conservation.     

Temporal shifts as elusive responses to anthropogenic stressors in a mammal community

Conservation decision-making often relies on species’ distribution changes in response to anthropogenic disturbances but overlook their temporal responses. Filling the knowledge gap on the temporal shifts as elusive responses of wild animals to human activity is important because this may provide information for more proactive conservation planning. In this study, we used camera traps in a field survey technique to investigate the trade-offs between spatial and temporal responses of a mammal community to major human activities in Qinling Mountains, China. We focused on five most abundant mammalian species including giant panda (Ailuropoda melanoleuca), takin (Budorcas taxicolor), wild boar (Sus scrofa), tufted deer (Elaphodus cephalophus), and Chinese goral (Naemorhedus griseus), and examined the drivers of, and the trade-offs between the change of their spatial distributions and daily activity patterns in response to anthropogenic disturbances. We found that in response to human interferences, giant panda and takin mainly changed their distributions, while wild boar, tufted deer and Chinese goral altered their daily activity patterns, indicating the elusive responses of the latter species under anthropogenic stressors. In addition, anthropogenic stressors such as farming and tourism have more profound impacts on mammal communities than previously revealed by species distribution modeling only. For nature reserves that aim to conserve multiple species simultaneously, a more flexible, adaptive management framework is thus needed to capture the trade-offs between multiple species’ spatial and temporal responses to anthropogenic disturbance.

     

Spatial and temporal adjustments allowing the coexistence among carnivores in Liguria (N-W Italy)

We investigated the seasonal spatial and temporal co-occurrence of three carnivore species in Liguria region (NW Italy)—the red fox (Vulpes vulpes), the European badger (Meles meles) and the wolf (Canis lupus)—using the information provided by camera-trapping monitoring. Data were collected from January 2013 to January 2015 by positioning camera traps in 200 sample stations. During 3479 trap days, we collected 1048 independent videos of target carnivore species, which revealed a general spatial coexistence among carnivores with some differences in seasonal occurrence of species. The red fox and the European badger showed temporal segregation, as their activity patterns suggested a differential use of night-time in all seasons. Activity patterns of the red fox and the wolf revealed moderate-high overlap and similar density distributions in all seasons except during winter. Coexistence between these species may be allowed by temporal segregation during winter and spatial segregation during spring. Finally, results regarding the European badger and the wolf suggest a moderate temporal segregation with a marked avoidance effect for the European badger induced by the presence of tracks left by wolves. Programmes aimed at carnivore conservation, and management should treat the entire guild, as it has been demonstrated that populations of different carnivores interact with each other in complex ways and that fine-scale mechanisms regulating carnivore assemblage influence different aspects of natural communities.     

Scale‐dependent strategies for coexistence of mesocarnivores in human‐dominated landscapes

Identifying factors influencing the distribution of and interactions within carnivore communities is important for understanding how they are affected by human activities. Species differ in their ability to adapt to humans depending on their degree of specialization in habitat use and feeding habits. This results in asymmetric changes in the ecology of co‐occurring species that can influence their interactions. We investigated whether human infrastructures and free‐ranging domestic dogs (a species typically associated with humans) influenced the co‐occurrence and habitat use of mesocarnivores in a landscape of high human population density in Maharashtra, India. We used 40 camera trap locations during 233 trapping nights and used Bayesian co‐occurrence occupancy models to investigate the habitat use and coexistence of species at different spatial scales. Additionally, we investigated their temporal overlap in space use. Indian foxes altered their habitat use both spatially and temporally in order to avoid free‐ranging domestic dogs and other larger competitors. The use of human infrastructure by jackals and jungle cats was limited by the presence of dogs. Our results illustrate how habitat use of smaller carnivore species changes both spatially and temporally in order to avoid larger competitors. We also show that the presence of species associated with humans mediates the influence of human infrastructures on the habitat use of mesocarnivores. We highlight the importance of acknowledging the potential impact of urbanization not only on single species, but also on the interactions within the community.     

Habitat and introduced predators influence the occupancy of small threatened macropods in subtropical Australia

Australia has had the highest rate of mammal extinctions in the past two centuries when compared to other continents. Frequently cited threats include habitat loss and fragmentation, changed fire regimes and the impact of introduced predators, namely the red fox (Vulpes vulpes) and the feral cat (Felis catus). Recent studies suggest that Australia's top predator, the dingo (Canis dingo), may have a suppressive effect on fox populations but not on cat populations. The landscape of fear hypothesis proposes that habitat used by prey species comprises high to low risk patches for foraging as determined by the presence and ubiquity of predators within the ecosystem. This results in a landscape of risky versus safe areas for prey species. We investigated the influence of habitat and its interaction with predatory mammals on the occupancy of medium‐sized mammals with a focus on threatened macropodid marsupials (the long‐nosed potoroo [Potorous tridactylous] and red‐legged pademelon [Thylogale stigmatica]). We assumed that differential use of habitats would reflect trade‐offs between food and safety. We predicted that medium‐sized mammals would prefer habitats for foraging that reduce the risk of predation but that predators would have a positive relationship with medium‐sized mammals. We variously used data from 298 camera trap sites across nine conservation reserves in subtropical Australia. Both dingoes and feral cats were broadly distributed, whilst the red fox was rare. Long‐nosed potoroos had a strong positive association with dense ground cover, consistent with using habitat complexity to escape predation. Red‐legged pademelons showed a preference for open ground cover, consistent with a reliance on rapid bounding to escape predation. Dingoes preferred areas of open ground cover whereas feral cats showed no specific habitat preference. Dingoes were positively associated with long‐nosed potoroos whilst feral cats were positively associated with red‐legged pademelons. Our study highlights the importance of habitat structure to these threatened mammals and also the need for more detailed study of their interactions with their predators.