Conventional wisdom on roosting behavior of Australian flying‐foxes—A critical review,and evaluation using new data

1. Fruit bats (Family: Pteropodidae) are animals of great ecological and economic importance, yet their populations are threatened by ongoing habitat loss and human persecution. A lack of ecological knowledge for the vast majority of Pteropodid species presents additional challenges for their conservation and management.
2. In Australia, populations of flying‐fox species (Genus: Pteropus) are declining and management approaches are highly contentious. Australian flying‐fox roosts are exposed to management regimes involving habitat modification, through human–wildlife conflict management policies, or vegetation restoration programs. Details on the fine‐scale roosting ecology of flying‐foxes are not sufficiently known to provide evidence‐based guidance for these regimes, and the impact on flying‐foxes of these habitat modifications is poorly understood.
3. We seek to identify and test commonly held understandings about the roosting ecology of Australian flying‐foxes to inform practical recommendations and guide and refine management practices at flying‐fox roosts.
4. We identify 31 statements relevant to understanding of flying‐fox roosting structure and synthesize these in the context of existing literature. We then contribute a contemporary, fine‐scale dataset on within‐roost structure to further evaluate 11 of these statements. The new dataset encompasses 13‐monthly repeat measures from 2,522 spatially referenced roost trees across eight sites in southeastern Queensland and northeastern New South Wales.
5. We show evidence of sympatry and indirect competition between species, including spatial segregation of black and grey‐headed flying‐foxes within roosts and seasonal displacement of both species by little red flying‐foxes. We demonstrate roost‐specific annual trends in occupancy and abundance and provide updated demographic information including the spatial and temporal distributions of males and females within roosts.
6. Insights from our systematic and quantitative study will be important to guide evidence‐based recommendations on restoration and management and will be crucial for the implementation of priority recovery actions for the preservation of these species in the future.

     

Spatial use and interaction of the invasive raccoon dog and the native red fox in Central Europe: competition or coexistence?

The main objective was to discover extent of interference and/or exploitative competition between the native red fox (Vulpes vulpes) and the introduced, invasive raccoon dog (Nyctereues proconoides) in the intensively used, agricultural landscape of northeast Germany (Mecklenburg-Western Pomerania) using very high frequency (VHF) radio telemetry. We recorded location data for 12 foxes and 16 raccoon dogs between July 2004 and December 2006. Species had similar average home range sizes estimated in each season (K95). Home ranges of adjacent raccoon dogs and foxes overlapped from 0.5 to 74.5 % with a mean of 26.4 %. We found a significantly different home range overlap index between the species showing that raccoon dog ranges shifted between seasons to a greater extent than red fox ranges. The raccoon dog differed significantly from the red fox in its use of habitat types, preferring dense vegetation cover and avoiding open areas. The red fox displayed less preference for or avoidance of specific habitat types. Moreover, an almost neutral inter-specific interaction index ranging from ?0.12 to 0.12 indicates that raccoon dogs and red foxes ignored each other. It is concluded that widespread and available resources and differences in spatial use patterns prevent competition between red foxes and raccoon dogs in the agricultural landscape of northeast Germany.     

Are British urban foxes (Vulpes vulpes) “bold”? The importance of understanding human–wildlife interactions in urban areas

Human–wildlife interactions are believed to be increasing in urban areas. In Britain, numerous media reports have stated that urban foxes (Vulpes vulpes) are becoming “bolder,” thereby posing a risk to public safety. However, such claims overlook how an individual''s personality might influence urban fox behavior. Personality determines multiple aspects of an animal''s interactions with both conspecifics and its environment, and can have a significant impact on how people perceive wildlife. Furthermore, describing urban foxes as “bold” confounds two different but inter‐related behaviors, both of which influence an animal''s propensity to take risks. Neophobia affects an animal''s reaction to novelty, wariness its reaction to potential threats. Since urban wildlife frequently encounters both novel and threatening stimuli, a highly adaptable species such as the red fox might be predicted to exhibit reduced neophobia and wariness. We investigated how social status influenced both behaviors in Bristol''s fox population. Dominant foxes were significantly more neophobic and warier than subordinates, which adopt a more exploratory and risk‐taking lifestyle to meet their energetic and other needs. We found no seasonal effect on neophobia and wariness, although this may be due to sample size. The presence of conspecifics decreased neophobia for dominants, and wariness for both dominants and subordinates. We highlight the importance of considering animal social status and personality when planning management protocols, since interventions that destabilize fox social groups are likely to increase the number of subordinate foxes in the population, thereby increasing rather than decreasing the number of interactions between humans and urban foxes.     

Finding a Fox: An Evaluation of Survey Methods to Estimate Abundance of a Small Desert Carnivore

The status of many carnivore species is a growing concern for wildlife agencies, conservation organizations, and the general public. Historically, kit foxes (Vulpes macrotis) were classified as abundant and distributed in the desert and semi-arid regions of southwestern North America, but is now considered rare throughout its range. Survey methods have been evaluated for kit foxes, but often in populations where abundance is high and there is little consensus on which technique is best to monitor abundance. We conducted a 2-year study to evaluate four survey methods (scat deposition surveys, scent station surveys, spotlight survey, and trapping) for detecting kit foxes and measuring fox abundance. We determined the probability of detection for each method, and examined the correlation between the relative abundance as estimated by each survey method and the known minimum kit fox abundance as determined by radio-collared animals. All surveys were conducted on 15 5-km transects during the 3 biological seasons of the kit fox. Scat deposition surveys had both the highest detection probabilities (p = 0.88) and were most closely related to minimum known fox abundance (r² = 0.50, P = 0.001). The next best method for kit fox detection was the scent station survey (p = 0.73), which had the second highest correlation to fox abundance (r² = 0.46, P<0.001). For detecting kit foxes in a low density population we suggest using scat deposition transects during the breeding season. Scat deposition surveys have low costs, resilience to weather, low labor requirements, and pose no risk to the study animals. The breeding season was ideal for monitoring kit fox population size, as detections consisted of the resident population and had the highest detection probabilities. Using appropriate monitoring techniques will be critical for future conservation actions for this rare desert carnivore.     

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.     

Den attendance patterns in swift foxes during pup rearing: varying degrees of parental investment within the breeding pair

Parental investment varies in mammalian species, with male care of young being more common in social and monogamous species. Monogamy is commonly observed in canid species, with both males and females, and often “helper” individuals, providing some degree of care for the young. Social units of the swift fox (Vulpes velox), a small North American canid species, usually consist of a male–female pair and occasionally helpers. The role of parental investment and behavior in swift fox society is currently poorly understood. We observed swift fox dens during the pup-rearing season in each of 2 years to evaluate attendance and frequency of visits to natal dens by adult males and females. Female foxes remained at dens longer and visited them more frequently than did male foxes. Female attendance and visitation decreased throughout the pup-rearing season as pups became older and more independent. Environmental factors, including climate and its effect on prey, appeared to contribute to differences in fox behavior between the 2 years. We observed only one fox outside of the breeding pair attending a den in each of the 2 years, both of which were males. We concluded that each of these two foxes were living within the social unit of the male–female pair as a trio, but not serving as a helper and contributing to the care of the pups. Our results increased knowledge of the ecology and behavior of the swift fox, a species of conservation concern in the Great Plains of North America.     

Ranking buffel: Comparative risk and mitigation costs of key environmental and socio‐cultural threats in central Australia

Changed fire regimes and the introduction of rabbits, cats, foxes, and large exotic herbivores have driven widespread ecological catastrophe in Australian arid and semi‐arid zones, which encompass over two‐thirds of the continent. These threats have caused the highest global mammal extinction rates in the last 200 years, as well as significantly undermining social, economic, and cultural practices of Aboriginal peoples of this region. However, a new and potentially more serious threat is emerging. Buffel grass (Cenchrus ciliaris L.) is a globally significant invader now widespread across central Australia, but the threat this ecological transformer species poses to biodiversity, ecosystem function, and culture has received relatively little attention. Our analyses suggest threats from buffel grass in arid and semi‐arid areas of Australia are at least equivalent in magnitude to those posed by invasive animals and possibly higher, because unlike these more recognized threats, buffel has yet to occupy its potential distribution. Buffel infestation also increases the intensity and frequency of wildfires that affect biodiversity, cultural pursuits, and productivity. We compare the logistical and financial challenges of creating and maintaining areas free of buffel for the protection of biodiversity and cultural values, with the creation and maintenance of refuges from introduced mammals or from large‐scale fire in natural habitats. The scale and expense of projected buffel management costs highlight the urgent policy, research, and financing initiatives essential to safeguard threatened species, ecosystems, and cultural values of Aboriginal people in central Australia.     

Water Developments and Canids in Two North American Deserts: A Test of the Indirect Effect of Water Hypothesis

Anthropogenic modifications to landscapes intended to benefit wildlife may negatively influence wildlife communities. Anthropogenic provisioning of free water (water developments) to enhance abundance and distribution of wildlife is a common management practice in arid regions where water is limiting. Despite the long-term and widespread use of water developments, little is known about how they influence native species. Water developments may negatively influence arid-adapted species (e.g., kit fox, Vulpes macrotis) by enabling water-dependent competitors (e.g., coyote, Canis latrans) to expand distribution in arid landscapes (i.e., indirect effect of water hypothesis). We tested the two predictions of the indirect effect of water hypothesis (i.e., coyotes will visit areas with free water more frequently and kit foxes will spatially and temporally avoid coyotes) and evaluated relative use of free water by canids in the Great Basin and Mojave Deserts from 2010 to 2012. We established scent stations in areas with (wet) and without (dry) free water and monitored visitation by canids to these sites and visitation to water sources using infrared-triggered cameras. There was no difference in the proportions of visits to scent stations in wet or dry areas by coyotes or kit foxes at either study area. We did not detect spatial (no negative correlation between visits to scent stations) or temporal (no difference between times when stations were visited) segregation between coyotes and kit foxes. Visitation to water sources was not different for coyotes between study areas, but kit foxes visited water sources more in Mojave than Great Basin. Our results did not support the indirect effect of water hypothesis in the Great Basin or Mojave Deserts for these two canids.     

Effects of Habitat on Competition Between Kit Foxes and Coyotes

Abstract: San Joaquin kit foxes (Vulpes macrotis mutica) are an endangered species with a narrow geographic range whose natural populations are limited by predation by coyotes (Canis latrans). In the warm, arid grassland and shrubland habitats where kit foxes occur, coyotes are more cover dependent than kit foxes, creating the possibility of habitat segregation. Effects of habitat variation on coyote and kit fox competition are unknown. We assessed exploitation and interference competition between coyotes and kit foxes in grassland and shrubland habitats to determine if such competition varies among habitats. With respect to exploitation competition, we evaluated habitat and spatial partitioning, diet, prey abundance, and survival for kit foxes and coyotes at the Lokern Natural Area in central California, USA, from January 2003 through June 2004. Kit foxes partitioned habitat, space, and diet with coyotes. Coyotes primarily used shrubland habitats whereas kit foxes selectively used burned grasslands. Kit foxes and coyotes had high dietary overlap with regards to items used, but proportional use of items differed between the 2 species. Kit foxes selected for Heermann's kangaroo rats (Dipodomys heermanni), which were closely tied to shrub habitats. With respect to interference competition, predation was the primary source of mortality for kit foxes, and survival of individual kit foxes was inversely related to proportion of shrub habitat within their home ranges. Our results suggest that a heterogeneous landscape may benefit kit foxes by providing habitat patches where predation risk may be lower.     

A division between foraging range and territory related to food distribution in the red fox

Spatial organization of the red fox (Vulpes vulpes schrencki) was investigated on the basis of seasonal food distribution in the Shiretoko National Park, Hokkaido from 1992 to 1994. Four periods were recorded pertaining to the distribution of 2 kinds of food resources: human food and spawning salmonid carcasses. The home range utilizations of radio-collared foxes were compared for the periods. In the periods when food was not spatially concentrated, resident foxes were territorial, showing exclusive distribution of home ranges between families, defense against intruding foxes at the edge of home ranges, and site specific dominance over intruding foxes. In contrast, during periods when food distribution was concentrated, home ranges overlapped. In the latter periods, foxes made round trips of up to 8 km from their territories to the localized concentration of food, the distance that foxes can travel within a day. This suggests that red foxes in this area have unique foraging ranges that include some seasonally available food outside their territories, and that these ranges depend on fluctuating food distribution caused by humans.     

Habitat selection by vulnerable golden bandicoots in the arid zone

In 2010, vulnerable golden bandicoots (Isoodon auratus) were translocated from Barrow Island, Western Australia, to a mainland predator‐free enclosure on the Matuwa Indigenous Protected Area. Golden bandicoots were once widespread throughout a variety of arid and semiarid habitats of central and northern Australia. Like many small‐to‐medium‐sized marsupials, the species has severely declined since colonization and has been reduced to only four remnant natural populations. Between 2010 and 2020, the reintroduced population of golden bandicoots on Matuwa was monitored via capture–mark–recapture data collection, which was used in spatially explicit capture–recapture analysis to monitor their abundance over time. In 2014, we used VHF transmitters to examine the home range and habitat selection of 20 golden bandicoots in the enclosure over a six‐week period. We used compositional analysis to compare the use of four habitat types. Golden bandicoot abundance in the enclosure slowly increased between 2010 and 2014 and has since plateaued at approximately one quarter of the density observed in the founding population on Barrow Island. The population may have plateaued because some bandicoots escape through the fence. Golden bandicoots used habitats dominated by scattered shrubland with spinifex grass more than expected given the habitat''s availability. Nocturnal foraging range was influenced by sex and trapping location, whereas diurnal refuge habitat, which was typically under a spinifex hummock with minimal overstory vegetation, was consistent across sex and trapping location. Our work suggests that diurnal refuge habitat may be an important factor for the success of proposed translocations of golden bandicoots.     

Microbiomes in Canidae

Because of their range expansion across North America, coyotes (Canis latrans) now occur sympatrically with numerous other predator species, including red foxes (Vulpes vulpes). This raises several interesting ecological questions, including if and how sympatry affects the diet and gut microbiomes of coyotes and red foxes. We examined the gut microbiomes of sympatric populations of coyotes and red foxes within two different National Parks in Virginia, USA, that differ in land use, vegetation, and anthropogenic disturbance: Prince William Forest Park (PRWI) and Manassas National Battlefield Park (MANA). From 2012 to 2017, scat samples from PRWI and MANA were collected and analyzed. Polymerase chain reaction (PCR) amplification of a region of the mitochondrial cytochrome‐b gene followed by restriction enzyme digestion of the PCR product was used to determine the origin of each scat sample. Next‐Generation DNA sequencing of a hypervariable 16S rRNA gene region was used to determine gut microbiome information about the scat samples. There was no evidence for a difference between the gut microbiomes of red foxes in either location, or for a difference between the gut microbiomes of red foxes at either location and coyotes at the location with lower human disturbance, PRWI. However, the gut microbiomes of coyotes at the location with higher anthropogenic disturbances, MANA, revealed a marked change from those found in red foxes at either location and from those in coyotes at the location with lower disturbances. The gut microbiomes of coyotes subjected to greater human impact may provide evidence of dysbiosis, indicative of increased physiological stress and reduced health. We discuss our observations in the context of understanding anthropogenic impacts on coyote and red fox interactions. Our results suggest that physiological stress in the form of human disturbance may play an important role in the composition of the gut microbiome of coyotes, which can affect their overall health.     

Behavioral audiogram of two Arctic foxes (Vulpes lagopus)

With increased polar anthropogenic activity, such as from the oil and gas industry, there are growing concerns about how Arctic species will be affected. Knowledge of species’ sensory abilities, such as auditory sensitivities, can be used to mitigate the effects of such activities. Herein, behavioral audiograms of two captive adult Arctic foxes (Vulpes lagopus) were measured using a yes/no paradigm and descending staircase method of signal presentation. Both foxes displayed a typical mammalian U-shaped audiometric curve, with a functional hearing range of 125 Hz–16 kHz (sensitivity ≤ 60 dB re: 20 μPa) and average peak sensitivity of 24 dB re: 20 μPa at 4 kHz. The foxes had a lower frequency range and sensitivity than would be expected when compared to previous audiograms of domestic dogs (Canis familiaris) and other carnivores. These differences indicate Arctic foxes (V. lagopus) may have a lower frequency range than previously expected, which was similar to the only other fox species tested to date, kit foxes (Vulpes macrotis). Alternatively, differences may be due to testing constraints, such as masking of test signals by ambient noise and/or an unintentionally trained conservative response bias, which most likely resulted in underestimated hearing curves. While results of this study should be interpreted with caution due to its limitations, findings indicate that foxes have a narrower frequency range than formerly presumed. Anthropogenic activities near fox habitats can mitigate their impacts by reducing noise at frequencies within the functional hearing range and peak sensitivities of this species.     

Effects of experimental watering but not warming on herbivory vary across a gradient of precipitation

Climate change can affect biotic interactions, and the impacts of climate on biotic interactions may vary across climate gradients. Climate affects biotic interactions through multiple drivers, although few studies have investigated multiple climate drivers in experiments. We examined the effects of experimental watering, warming, and predator access on leaf water content and herbivory rates of woolly bear caterpillars (Arctia virginalis) on a native perennial plant, pacific silverweed (Argentina anserina ssp. pacifica), at two sites across a gradient of precipitation in coastal California. Based on theory, we predicted that watering should increase herbivory at the drier end of the gradient, predation should decrease herbivory, and watering and warming should have positive interacting effects on herbivory. Consistent with our predictions, we found that watering only increased herbivory under drier conditions. However, watering increased leaf water content at both wetter and drier sites. Warming increased herbivory irrespective of local climate and did not interact with watering. Predation did not affect herbivory rates. Given predictions that the study locales will become warmer and drier with climate change, our results suggest that the effects of future warming and drying on herbivory may counteract each other in drier regions of the range of Argentina anserina. Our findings suggest a useful role for range‐limit theory and the stress‐gradient hypothesis in predicting climate change effects on herbivory across stress gradients. Specifically, if climate change decreases stress, herbivory may increase, and vice versa for increasing stress. In addition, our work supports previous suggestions that multiple climate drivers are likely to have dampening effects on biotic interactions due to effects in different directions, though this is context‐dependent.     

Mitochondrial Genomes Suggest Rapid Evolution of Dwarf California Channel Islands Foxes (Urocyon littoralis)

Island endemics are typically differentiated from their mainland progenitors in behavior, morphology, and genetics, often resulting from long-term evolutionary change. To examine mechanisms for the origins of island endemism, we present a phylogeographic analysis of whole mitochondrial genomes from the endangered island fox (Urocyon littoralis), endemic to California’s Channel Islands, and mainland gray foxes (U. cinereoargenteus). Previous genetic studies suggested that foxes first appeared on the islands >16,000 years ago, before human arrival (~13,000 cal BP), while archaeological and paleontological data supported a colonization >7000 cal BP. Our results are consistent with initial fox colonization of the northern islands probably by rafting or human introduction ~9200–7100 years ago, followed quickly by human translocation of foxes from the northern to southern Channel Islands. Mitogenomes indicate that island foxes are monophyletic and most closely related to gray foxes from northern California that likely experienced a Holocene climate-induced range shift. Our data document rapid morphological evolution of island foxes (in ~2000 years or less). Despite evidence for bottlenecks, island foxes have generated and maintained multiple mitochondrial haplotypes. This study highlights the intertwined evolutionary history of island foxes and humans, and illustrates a new approach for investigating the evolutionary histories of other island endemics.     

Seasonal pulses of migratory prey and annual variation in small mammal abundance affect abundance and reproduction by arctic foxes

We examined how large seasonal influxes of migratory prey influenced population dynamics of arctic foxes and how this varied with fluctuations in small mammal (lemming and vole) abundance—the main prey of arctic foxes throughout most of their range. Specifically, we compared how arctic fox abundance, breeding density and litter size varied inside and outside a large goose colony and in relation to annual variation in small mammal abundance. Information-theoretic model selection showed that (1) breeding density and fox abundance were 2–3 times higher inside the colony than they were outside the colony and (2) litter size, breeding density and annual variation in fox abundance in the colony tracked fluctuations in lemming abundance. The influence of lemming abundance on reproduction and abundance of arctic foxes outside the colony was inconclusive, largely because fox densities outside the colony were low, which made it difficult to detect such relationships. Lemming abundance was, thus, the main factor governing reproduction and abundance of arctic foxes in the colony, whereas seasonal influxes of geese and their eggs provided foxes with external subsidies that elevated breeding density and fox abundance above that which lemmings could support. This study highlights (1) the relative importance of migratory prey and other foods on the abundance and reproduction by local consumers and (2) how migratory animals function as vectors of nutrient transfer between distant ecosystems such as Arctic environments and wintering areas by geese thousands of kilometres to the south.     

Natal den selection by sympatric arctic and red foxes on Herschel Island,Yukon, Canada

In the twentieth century, red fox (Vulpes vulpes) expanded into the Canadian Arctic, where it competes with arctic fox (Vulpes lagopus) for food and shelter. Red fox dominates in physical interactions with the smaller arctic fox, but little is known about competition between them on the tundra. On Hershel Island, north Yukon, where these foxes are sympatric, we focused on natal den choice, a critical aspect of habitat selection. We tested the hypothesis that red fox displaces arctic fox from dens in prey-rich habitats. We applied an approach based on model comparisons to analyse a 10-year data set and identify factors important to den selection. Red fox selected dens in habitats that were more prey-rich in spring. When red foxes reproduced, arctic fox selected dens with good springtime access, notably many burrows unblocked by ice and snow. These provided the best refuge early in the reproductive season. In the absence of red foxes, arctic foxes selected dens offering good shelter (i.e. large isolated dens). Proximity to prey-rich habitats was consistently less important than the physical aspects of dens for arctic fox. Our study shows for the first time that red foxes in the tundra select dens associated primarily with prey-rich areas, while sympatric arctic foxes do not. These results fit a model of red fox competitively interfering with arctic fox, the first detailed study of such competition in a true arctic setting.     

The effect of habitat and human disturbance on the spatiotemporal activity of two urban carnivores: The results of an intensive camera trap study

With rising urbanization, the presence of urban wildlife is becoming more common, increasing the need for wildlife‐friendly spaces in urban planning. Despite this, understanding is limited to how wildlife exploits urban environments and interacts with human populations, and this is vital to our ability to manage and conserve wildlife in urban habitats. Here, we investigate how two urban mammal species, the red fox (Vulpes vulpes) and the European badger (Meles meles), exploit urban environments. Using intensive camera trap surveys, we assessed how habitat and human disturbance influenced the spatiotemporal activity of these species across south‐west London. Firstly, we found elevated activity levels of both species at boundaries and within built‐up areas, suggesting movement paths follow anthropogenic features. However, badgers were most active in woodland, indicating the importance of high cover habitats suitable for setts and foraging. Secondly, we found badger activity levels were negatively affected by human activity, whilst foxes were unaffected. Further investigation suggested foxes may adapt their activity patterns to avoid human disturbance, with badger activity patterns less plastic. Whilst the results of this study are useful for both the conservation and management of urban wildlife populations, these results also show potential factors which either facilitate or limit wildlife from fully exploiting urban environments.