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Predators induce stress in prey and can have beneficial effects in ecosystems, but can also have negative effects on biodiversity if they are overabundant or have been introduced. The growth of human populations is, at the same time, causing degradation of natural habitats and increasing interaction rates of humans with wildlife, such that conservation management routinely considers the effects of human disturbance as tantamount to or surpassing those of predators. The need to simultaneously manage both of these threats is particularly acute in urban areas that are, increasingly, being recognized as global hotspots of wildlife activity. Pressures from altered predator–prey interactions and human activity may each initiate fear responses in prey species above those that are triggered by natural stressors in ecosystems. If fear responses are experienced by prey at elevated levels, on top of responses to multiple environmental stressors, chronic stress impacts may occur. Despite common knowledge of the negative effects of stress, however, it is rare that stress management is considered in conservation, except in intensive ex situ situations such as in captive breeding facilities or zoos. We propose that mitigation of stress impacts on wildlife is crucial for preserving biodiversity, especially as the value of habitats within urban areas increases. As such, we highlight the need for future studies to consider fear and stress in predator–prey ecology to preserve both biodiversity and ecosystem functioning, especially in areas where human disturbance occurs. We suggest, in particular, that non-invasive in situ investigations of endocrinology and ethology be partnered in conservation planning with surveys of habitat resources to incorporate and reduce the effects of fear and stress on wildlife.

Wildlife are increasingly being found in urban habitats, and likely rely on some resources in suburban household yards, which exposes them to the effects of yard management and human and pet activities. We compared the relationships between these potential disturbances and benefits to the number of different types of wildlife sighted by householders, using written surveys. Owing to the inability of many household respondents to identify animals to the species or genus level, each different ‘type’ of animal individually listed was counted to generate the total number of types of wildlife observed by each household. We found that relatively more types of wildlife were observed by residents whose yards provided ease of faunal access under or through fences, had reduced pesticide use, increased levels of anthropogenic noise, and increased presence of pets in yards. The latter two associations likely relate to the increased opportunities to observe wildlife in yards that each creates. We also investigated the use of yards by wildlife and domestic pets in open compared to more vegetated habitats by day and night, using motion-sensor cameras. All animals observed were compared to the activity of introduced brown and black rats (Rattus norvegicus, R. rattus), owing to their wild origins but long commensal history with humans. Camera images indicated that animals’ natural activity periods were maintained in yards. Brown antechinuses (Antechinus stuartii), northern brown bandicoots (Isoodon macrourus), domestic cats (Felis catus) and native birds (species as listed below) each preferred sheltered or vegetated habitats over open habitats, when compared to the introduced rats that showed little habitat preference. However, unlike the other species, the native birds used open areas more than vegetated or sheltered areas when compared within their group only. The common brushtail possum (Trichosurus vulpecula) was observed to use open areas comparatively more than the introduced rats, but used vegetated or sheltered habitats more when compared to self only. The domestic dog (Canis familiaris) and red fox (Vulpes vulpes) used open areas more than vegetated or sheltered areas, when compared to the introduced rats, and against themselves. This indicated a level of coping with urban stressors by the native animals, but with a reliance on more vegetated habitats to allow for natural stress-relieving behaviours of escape or hiding. Here, we offer insights into how each of these findings may be used to help educate and motivate increased household responsibility for urban wildlife conservation.

In environments driven by unpredictable resource pulses, populations of many consumer species experience dramatic fluctuations in abundance and spatial extent. Predator–prey relationships in these acyclic systems are poorly understood in particular with respect to the level of prey specialisation shown by nomadic predators. To understand the dynamics of such a system I examined the response to rodent outbreaks by the letter-winged kite (Elanus scriptus) in the Simpson Desert, Australia; a region that experiences major pulses in primary productivity, driven by unpredictable rainfall events. The kite feeds on small mammals and is the only night-hunting species in the Accipitridae. Letter-winged kites irrupted in the area on only three occasions during 20 years of sampling (1999–2019) and remained for a maximum of 20 months. Each period of kite occupation occurred only during the increase and/or peak phase of rodent population cycles (which occurred three times during the study). During each period kite diet was dominated by small (10–50 g body mass) quadrupedal rodents (Pseudomys australis, P. hermannsburgensis, Mus musculus). Abundance of these species varied across the three outbreaks and kites typically captured them in proportion to availability. The large body mass (134 g) long-haired rat (Rattus villosissimus) was abundant during one outbreak but was infrequently consumed. The bipedal spinifex hopping-mouse (Notomys alexis) was within the kites’ favoured prey size range (35 g) but was consistently avoided. The flexibility in prey selection by letter-winged kites appears to be an important adaptation for survival and reproduction by species exploiting acyclic rodent outbreaks.

Bird assemblages in arid Australia are often characterized as being highly variable through time in response to boom and bust dynamics, although the importance of habitat in structuring assemblages at a local‐scale is also recognized. We use a novel approach to investigate the importance of rainfall variability in structuring bird assemblages in a resource‐limited environment. Monthly bird surveys were conducted at ten plots for 8 years at a botanical and zoological park in central Australia, including five irrigated plots within a fenced area and five natural plots outside. Irrigation—used to promote growth, flowering, and fruiting of plants—created an artificial resource‐enhanced environment against which the response of birds to natural fluctuations in season and rainfall were compared. Species richness was generally maintained at a higher level in resource‐enhanced plots during dry times but was higher in natural plots when rainfall was high, mainly due to increases in granivores and insectivores. Honeyeaters were consistently more abundant at irrigated plots. Rainfall was important in structuring bird assemblages at all plots; however, assemblages were more stable in irrigated plots and did not respond as dramatically to a period of very high rainfall. The comparative smoothing of fluctuations in the composition and abundance of birds in irrigated areas highlights the importance of primary productivity, normally tied to rainfall, in driving temporal change in arid‐zone bird communities. There was also evidence that different plots in differing habitats supported distinct bird assemblages and that this spatial distinctiveness persisted irrespective of rainfall and determined, to some extent, the response to rainfall. Our study is one of few long‐term studies of arid bird assemblages and highlights the importance of both long‐term cycles of productivity driven by rain and season as well as site differences in the dynamics of arid‐zone bird communities. These insights are particularly valuable as climate change further exacerbates rainfall variability worldwide and initiatives to conserve avifauna in increasingly extreme environments may be required. Arid‐zone bird assemblages in natural areas were contrasted with areas where resources were enhanced by artificial irrigation over 8 years under average to dry conditions and including a time of very high rainfall. Rainfall was important in structuring bird assemblages and a comparative smoothing of fluctuations in the composition and abundance of birds in irrigated areas highlights the importance of primary productivity in driving temporal change in arid‐zone bird communities.

A clear understanding of a species’ diet is crucial in understanding its spatio-temporal dynamics, and is, therefore, pertinent to conservation considerations. The diet of the Grey Falcon (Falco hypoleucos), a rare and threatened predator endemic to the Australian arid and semi-arid zone, is subject to diverging assertions; therefore, we studied its diet through direct observation of food ingestion during more than 17 years of fieldwork across the species’ distribution. We found that Grey Falcons of all ages fed almost exclusively on a single type of food, namely, birds, and non-avian food items never constituted a substantial portion of any individual’s diet. The extraordinary circumstances that were associated with the ingestion of non-avian food suggest strongly that, across its vast distribution, throughout the year, and throughout its life, the Grey Falcon feeds almost exclusively on birds. Further, we compared the diets of all Falco species and found that the dietary specialization is most extreme in the Grey Falcon, more so than even in the Taita (F. fasciinucha) and Peregrine Falcons (F. peregrinus). Based on aspects of the species’ environment and relative prey availability, we offer an evolutionary explanation of the apparently unique dietary specialization of the arid-adapted Grey Falcon.

We examined population dynamics and trophic ecology of a predator–prey system in the Simpson Desert, Australia, consisting of an assemblage of small mammals (body mass < 100 g) and 4 species of predators: the endemic letter-winged kite (Elanus scriptus), a nocturnal-hunting rodent specialist; and 3 introduced mammalian predators (dingo [Canis lupus dingo], European red fox [Vulpes vulpes], and house cat [Felis catus]). This is the 1st comprehensive study of the responses of both the kite and introduced carnivores to a rodent outbreak. The 3.5-year study period included a population outbreak of about 24 months duration involving 3 native rodent species. Mammalian predators and kites exhibited similar population responses. Kites immigrated into the area within 6 months of the outbreak commencing, and remained while rodent abundance was high; however, all birds left the area after rodent populations crashed within a 6-week period. Dingoes and foxes were more abundant than cats and both species increased during the outbreak. All carnivores were resident. The letter-winged kite fed almost entirely on rodents. Rodents were the main prey of the 3 mammalian predators during the outbreak; however, all species had intermediate niche breadths. Dietary overlap between the kite and each carnivore was high during the rodent outbreak. During a nonoutbreak period, predation on rodents by the red fox remained high, whereas that by the dingo declined. We estimated the number of average-sized rodents (body mass 32.65 g) eaten daily by a nonreproducing individual to range from 1 (letter-winged kite) to 6 (red fox). We also estimated that the 3 mammalian predators (combined) captured 11 times as many rodents per day as letter-winged kites. There is considerable potential for food-based competition between the kite and introduced mammalian predators, particularly the red fox and house cat, in arid Australia.

Food availability, ambient temperatures (T a), and prevailing weather conditions have long been presumed to influence torpor use. To a large extent, this is based on measurements in the laboratory of animals placed on restricted diets and kept at low T a. Information on the determinants of torpor employment in the field is limited. We assessed winter torpor by insectivorous, free-ranging Australian owlet-nightjars (Aegotheles cristatus; 22 birds, 834 bird-days over six winters). Birds in three habitats were investigated to test whether torpor use is affected by annual T a, rainfall, and arthropod abundance. Owlet-nightjars entered daily torpor regularly at all sites. Torpor frequency, depth and bout duration were greatest during two periods with lower arthropod abundance, providing rare evidence of the link between food availability and torpor patterns of wild birds. Temporal organization of torpor was similar among sites, and nocturnal torpor was more frequent than previously reported. Our findings quantitatively demonstrate that reduced food resources affect torpor usage independently from T a, and support the view that food availability is a primary ecological determinant of torpor use in the wild.

Aim: Predators often have important roles in structuring ecosystems via their effects on each other and on prey populations. However, these effects may be altered in the presence of anthropogenic food resources, fuelling debate about whether the availability of such resources could alter the ecological role of predators. Here, we review the extent to which human-provided foods are utilised by terrestrial mammalian predators (> 1 kg) across the globe. We also assess whether these resources have a direct impact on the ecology and behaviour of predators and an indirect impact on other co-occurring species. Location: Global. Methods: Data were derived from searches of the published literature. To summarise the data we grouped studies based on the direct and indirect effects of resource subsidies on predators and co-occurring species. We then compared the types of predators accessing these resources by grouping species taxonomically and into the following categories: (1) domesticated species, (2) mesopredators and (3) top predators. Results: Human-provided foods were reported to be utilised by 36 terrestrial predator species in 34 different countries. In the presence of these resources we found that: (1) predator abundance increased, (2) the dietary preferences of predators altered to include the food subsidy, (3) life-history parameters such as survival, reproduction and sociality shifted to the benefit or detriment of the predator, and (4) predators changed their home ranges, activity and movements. In some instances, these modifications indirectly affected co-occurring species via increased predation or competition. Main conclusions: The availability of human-provided food to predators often results in behavioural or population-induced changes to predators and trophic cascades. We conclude that there is an urgent need to reduce the access of predators to food subsidies to minimise human-wildlife conflicts and to preserve the integrity of ecosystem functioning in human-influenced landscapes world-wide.

Little is known about the energy conservation strategies of free‐ranging marsupials living in resource‐poor Australian deserts. We studied activity patterns and torpor of free‐living mulgaras (Dasycercus blythi) in arid central Australia during the winter of 2006. Mulgaras are small (∼75 g), nocturnal, insectivorous marsupials, with a patchy distribution in hummock grasslands. Mulgaras (six males, three females) were implanted intraperitoneally with temperature‐sensitive transmitters and monitored for 6–55 d. Temperature profiles for different microhabitats and the thermal properties of soil and a number of burrows were also measured. Air temperature ranged from −3°C at night to 30°C during the day. Although burrows buffered temperature extremes, the thermal diffusivity of the sandy soil was high, and many burrows were shallow. Hence, soil and burrow temperatures averaged about 15°C. The activity of mulgaras was often restricted to a few hours after sunset, before they retired into their burrows. Mulgaras employed torpor frequently, often entering torpor during the night and arousing around midday, with arousals occurring later on cooler days. Shallow burrows allowed cooling below meanT soil. Consequently, body temperatures as low as 10.8°C were observed. The longest torpor bout was 20.8 h. Torpor patterns changed seasonally and differed between males and females. From June to August, females entered torpor almost daily despite mating and gestation, but from the end of the gestation period onward, they remained normothermic. In contrast, males showed only shallow and short torpor during the mating season, but from mid‐July, a transition to more frequent and deeper torpor resembling that of females was observed. Apparently, in both sexes, the reproductive effort entails energetic costs, but torpor, as an energy‐saving mechanism, and reproduction are not exclusive in mulgaras. In a resource‐poor environment during the least productive part of the year, frequent torpor seems to provide the means to compensate for the increased energetic costs associated with reproduction.

Policies for conservation outside protected areas, such as those designed to address the decline in Australian mammals, will not result in net improvements unless they address barriers to proenvironmental behavior. We used a mixed-methods approach to explore potential value-action gaps (disconnects between values and subsequent action) for small mammal conservation behaviors among pastoralists in dryland Australia. Using semistructured surveys and open-ended interviews (n = 43), we explored values toward small mammals; uptake of a range of current and intended actions that may provide benefit to small mammals; and potential perceived barriers to their uptake. Pastoralists assigned great conservation value to small mammals; over 80% (n = 36) agreed to strongly agreed that small mammals on their property were important. These values did not translate into stated willingness to engage in voluntary cessation of wild-dog control (r² = 0.187, p = 0.142, n = 43). However, assigning great conservation value to small mammals was strongly related to stated voluntary willingness to engage in the proenvironmental behavior most likely to result in benefits to small mammals: cat and fox control (r² = 0.558, p = 0.000, n = 43). There was no significant difference between stated voluntarily and incentivized willingness to engage in cat and fox control (p = 0.862, n = 43). The high levels of willingness to engage in voluntary cat and fox control highlight a potential entry point for addressing Australia's mammal declines because the engagement of pastoralists in conservation programs targeting cat and fox control is unlikely to be prevented by attitudinal constraints. Qualitative data suggest there is likely a subpopulation of pastoralists who value small mammals but do not wish to engage informal conservation programs due to relational barriers with potential implementers. A long-term commitment to engagement with pastoralists by implementers will thus be necessary for conservation success. On-property cat and fox control programs that build and leverage trust, shared goals, collaboration, and shared learning experiences between stakeholders and that explicitly recognize the complexity of small mammal dynamics and the property-level ecological knowledge of pastoralists are more likely to gain traction. Las políticas para la conservación afuera de las áreas protegidas, como aquellas designadas para enfocarse en la declinación de los mamíferos australianos, no resultarán en mejoras netas a menos que estén dirigidas a las barreras ante el comportamiento pro-ambiental. Utilizamos una estrategia de métodos mixtos para explorar el potencial de los vacíos de acción-valor (desconexiones entre los valores y las acciones subsecuentes) para los comportamientos de conservación de los mamíferos pequeños entre los pastores en las tierras secas de Australia. Con el uso de censos semi-estructurados y entrevistas de preguntas abiertas (n = 43), exploramos los valores en torno a los mamíferos pequeños; la aceptación de un rango de acciones actuales e intencionadas que pueden proporcionar beneficios para los mamíferos pequeños; y el potencial de las barreras percibidas ante esta aceptación. Los pastores asignaron un valor alto de conservación a los mamíferos pequeños; más del 80 % (n = 36) estuvieron de acuerdo o considerablemente de acuerdo con que los mamíferos pequeños en su propiedad eran importantes. Estos valores no se tradujeron a una disposición mencionada por participar en el cese voluntario del control de perros salvajes (r 2 = 0.187, ñ = 0.142, ç = 43). Sin embargo, asignarle un gran valor de conservación a los mamíferos pequeños estuvo relacionado fuertemente con la disposición voluntaria mencionada por participar en el comportamiento pro-ambiental con mayor probabilidad de resultar en beneficios para los mamíferos pequeños: el control de gatos y zorros (r² = 0.558, p = 0.000, n = 43). No hubo una diferencia significativa entre la disposición mencionada voluntariamente y la alentada por participar en el control de gatos y zorros (p = 0.862, n = 43). El nivel alto de disponibilidad por participar voluntariamente en el control de gatos y zorros resalta un punto de entrada potencial para enfocarse en las declinaciones de los mamíferos de Australia, porque no es probable que la participación de los pastores en los programas de conservación con el objetivo de controlar gatos y zorros sea prevenida por restricciones actitudinales. Los datos cualitativos sugieren que probablemente hay una sub-población de pastores que valoran a los mamíferos pequeños pero no desean participar en programas formales de conservación debido a las barreras de relación con los implementadores potenciales. Entonces será necesario un compromiso a largo plazo con los pastores por parte de los implementadores para que haya éxito de conservación. Es más probable que ganen tracción los programas de control de gatos y zorros en las propiedades que construyan y fomenten la confianza, los objetivos compartidos, la colaboración y las experiencias de aprendizaje compartido entre los accionistas y que reconozcan explícitamente la complejidad de las dinámicas de los mamíferos pequeños y el conocimiento ecológico a nivel propiedad de los pastores.