Fear, foraging and olfaction Haswell, Peter M.; Jones, Katherine A.; Kusak, Josip ...
Oecologia,
07/2018, Letnik:
187, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Where direct killing is rare and niche overlap low, sympatric carnivores may appear to coexist without conflict. Interference interactions, harassment and injury from larger carnivores may still pose ...a risk to smaller mesopredators. Foraging theory suggests that animals should adjust their behaviour accordingly to optimise foraging efficiency and overall fitness, trading off harvest rate with costs to fitness. The foraging behaviour of red foxes, Vulpes vulpes, was studied with automated cameras and a repeated measures giving-up density (GUD) experiment where olfactory risk cues were manipulated. In Plitvice Lakes National Park, Croatia, red foxes increased GUDs by 34% and quitting harvest rates by 29% in response to wolf urine. In addition to leaving more food behind, foxes also responded to wolf urine by spending less time visiting food patches each day and altering their behaviour in order to compensate for the increased risk when foraging from patches. Thus, red foxes utilised olfaction to assess risk and experienced foraging costs due to the presence of a cue from gray wolves, Canis lupus. This study identifies behavioural mechanisms which may enable competing predators to coexist, and highlights the potential for additional ecosystem service pathways arising from the behaviour of large carnivores. Given the vulnerability of large carnivores to anthropogenic disturbance, a growing human population and intensifying resource consumption, it becomes increasingly important to understand ecological processes so that land can be managed appropriately.
Overconsumption presents a major obstacle to social and environmental sustainability. Systemic social, legal, and economic strategies are absolutely necessary, but individuals are still accountable ...for their lifestyle choices and associated environmental footprints. Anti-consumption (rejection, reduction, reclamation) has its limitations, but could contribute to pro-environmental change, helping resolve biodiversity and climate crises. Regardless of societal consumption patterns, individuals can still make great gains in well-being and personal development by upholding their environmental and social values, minimizing personal resource consumption. Challenging the cultural norms of overconsumption requires individuals to employ mental fortitude in attempts to act justly toward the entire community of life. As a species, given our rational capabilities and ability to meet our basic needs, we are highly capable of bettering ourselves and our environment.
An understanding of animal behaviour is important if conservation initiatives are to be effective. However, quantifying the behaviour of wild animals presents significant challenges. Remote‐sensing ...camera traps are becoming increasingly popular survey instruments that have been used to non‐invasively study a variety of animal behaviours, yielding key insights into behavioural repertoires. They are well suited to ethological studies and provide considerable opportunities for generating conservation‐relevant behavioural data if novel and robust methodological and analytical solutions can be developed. This paper reviews the current state of camera‐trap‐based ethological studies, describes new and emerging directions in camera‐based conservation behaviour, and highlights a number of limitations and considerations of particular relevance for camera‐based studies. Three promising areas of study are discussed: (1) documenting anthropogenic impacts on behaviour; (2) incorporating behavioural responses into management planning and (3) using behavioural indicators such as giving up densities and daily activity patterns. We emphasize the importance of reporting methodological details, utilizing emerging camera trap metadata standards and central data repositories for facilitating reproducibility, comparison and synthesis across studies. Behavioural studies using camera traps are in their infancy; the full potential of the technology is as yet unrealized. Researchers are encouraged to embrace conservation‐driven hypotheses in order to meet future challenges and improve the efficacy of conservation and management processes.
Camera traps are well suited to ethological studies and provide considerable opportunities for the generation of important behavioural data which would benefit conservation processes. We provide a review of current applications of camera traps to behavioural studies, describe new and emerging directions in camera‐based conservation behaviour, and highlight a number of limitations and considerations of particular relevance to behavioural studies conducted using camera traps. We suggest three promising areas for the growth of camera‐based inferences on animal behaviour to support conservation: (1) documenting anthropogenic impacts on behaviour; (2) using behavioural indicators such as GUD and daily activity patterns; and (3) behaviour‐based conservation management.
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.
Worldwide, native predators are killed to protect livestock, an action that can undermine wildlife conservation efforts and create conflicts among stakeholders. An ongoing example is occurring in the ...western United States, where wolves (Canis lupus) were eradicated by the 1930s but are again present in parts of their historic range. While livestock losses to wolves represent a small fraction of overall livestock mortality, the response to these depredations has resulted in widespread conflicts including significant efforts at lethal wolf control to reduce impacts on livestock producers, especially those with large-scale grazing operations on public lands. A variety of nonlethal methods have proven effective in reducing livestock losses to wolves in small-scale operations but in large-scale, open-range grazing operations, nonlethal management strategies are often presumed ineffective or infeasible. To demonstrate that nonlethal techniques can be effective at large scales, we report a 7-year case study where we strategically applied nonlethal predator deterrents and animal husbandry techniques on an adaptive basis (i.e., based on terrain, proximity to den or rendezvous sites, avoiding overexposure to techniques such as certain lights or sound devices that could result in wolves losing their fear of that device, etc.) to protect sheep (Ovis aries) and wolves on public grazing lands in Idaho. We collected data on sheep depredation mortalities in the protected demonstration study area and compared these data to an adjacent wolf-occupied area where sheep were grazed without the added nonlethal protection measures. Over the 7-year period, sheep depredation losses to wolves were 3.5 times higher in the Nonprotected Area (NPA) than in the Protected Area (PA). Furthermore, no wolves were lethally controlled within the PA and sheep depredation losses to wolves were just 0.02% of the total number of sheep present, the lowest loss rate among sheep-grazing areas in wolf range statewide, whereas wolves were lethally controlled in the NPA. Our demonstration project provides evidence that proactive use of a variety of nonlethal techniques applied conditionally can help reduce depredation on large open-range operations.
Large carnivores are depicted to shape entire ecosystems through top-down processes. Studies describing these processes are often used to support interventionist wildlife management practices, ...including carnivore reintroduction or lethal control programs. Unfortunately, there is an increasing tendency to ignore, disregard or devalue fundamental principles of the scientific method when communicating the reliability of current evidence for the ecological roles that large carnivores may play, eroding public confidence in large carnivore science and scientists. Here, we discuss six interrelated issues that currently undermine the reliability of the available literature on the ecological roles of large carnivores: (1) the overall paucity of available data, (2) reliability of carnivore population sampling techniques, (3) general disregard for alternative hypotheses to top-down forcing, (4) lack of applied science studies, (5) frequent use of logical fallacies, and (6) generalisation of results from relatively pristine systems to those substantially altered by humans. We first describe how widespread these issues are, and given this, show, for example, that evidence for the roles of wolves (Canis lupus) and dingoes (Canis lupus dingo) in initiating trophic cascades is not as strong as is often claimed. Managers and policy makers should exercise caution when relying on this literature to inform wildlife management decisions. We emphasise the value of manipulative experiments and discuss the role of scientific knowledge in the decision-making process. We hope that the issues we raise here prompt deeper consideration of actual evidence, leading towards an improvement in both the rigour and communication of large carnivore science.
Greater understanding of intraguild dynamics in rodent communities and of how house mice, Mus musculus, interact with wild sympatric rodents is needed. House mice can be a particularly virulent ...invasive species, presenting a potential threat to native biodiversity. In the Mojave Desert, western harvest mice, Reithrodontomys megalotis and the endangered Amargosa vole, Microtus californicus scirpensis, inhabit a fragmented desert wetland ecosystem. The Amargosa vole relies heavily on bulrush, Schoenoplectus americanus, for food, as well as thermal and predator refuge. We used two species occupancy models and estimated activity pattern overlap to explore spatial and temporal interactions within this rodent guild. For each species pairing, we compared the relative performance of a series of candidate occupancy models, with the most supported model structures and components distinguished by AICc and AICc weight. We found that voles reduced the detectability of western harvest mice and house mice, but did not spatially exclude them. Our findings also suggested that voles were more detectable in bulrush stands as bulrush cover increased, whereas house mice and western harvest mice were negatively associated with bulrush cover. House mice and western harvest mice had high activity pattern overlap, (Δ̂4 0.89, 95% CI = 0.85-0.96), which was greater with each other than with voles (Δ̂4 0.69, 95% CI = 0.57-0.75 and Δ̂4 0.66, 95% CI = 0.49-0.70, respectively). House mice were also more detectable in the presence of western harvest mice, suggesting niche overlap or an attraction to them. Our observations suggest that, during the summer months, Amargosa voles could be a limiting factor on the behaviour and/or population densities of smaller rodent species in bulrush habitat. Drought exacerbated habitat changes may have contributed to house mouse expansion and vole decline in the region. While a deeper understanding of trophic dynamics is required, continued efforts to preserve the endangered Amargosa vole and it's habitat may also help mitigate any potential harm caused by free-living house mice in these desert wetlands.
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•Endangered Amargosa voles inhabit bulrush wetlands in the Mojave Desert.•Amargosa voles reduced the detectability of house mice & western harvest mice.•Amargosa voles may suppress the activity or density of these smaller rodents.•House mice & western harvest mice also overlap strongly in time and space.•Conserving Amargosa voles & mitigating drought may help control house mice.
A societal shift toward plant dominant diets and a reduction in livestock rearing could have broad social, environmental and conservation benefits. Livestock husbandry, however, has a wealthy ...cultural history, strong support and high consumer demand. It is therefore likely to continue as a major land use and conservation issue for predators. From a producer’s perspective, the primary goals of livestock protection are maximising, or at least maintaining, production by minimising losses and mitigating detriment to stock welfare. Lethal removal of predators remains a commonplace solution. Such management measures are questionable as they raise animal welfare and conservation concerns, risk inhibiting ecological processes, are often expensive, and in some circumstances, exacerbate livestock predation problems. Non-lethal alternatives can facilitate co-existence between livestock farmers and predators, ideally reducing the ecological impact of pastoralism and achieving conservation goals. The need for rigorous study of non-lethal approaches has however been recently highlighted. Tools and methods involved in livestock protection, as well as the theoretical basis of how we perceive and manage the problem, require deeper consideration. Non-lethal approaches require knowledgeable implementation and an effective decision making system is a prerequisite for successful practice. Livestock predation and its prevention are fundamentally influenced by the underlying principles of foraging ecology and risk theory. We propose that manipulating elements of Brown’s (1988) quitting harvest rate model provides a useful conceptual framework for reducing livestock predation and encouraging coexistence.
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