Drivers of habitat quality for a reintroduced elk herd

Understanding spatiotemporal variation in habitat quality is essential for guiding wildlife reintroduction and restoration programs. The habitat productivity hypothesis posits that home range size is inversely related to habitat quality. Thus, home range size may be used as a proxy for habitat quality and can identify important land cover features for a recovering species. We sought to quantify variation in home range size across the biological cycle (seasons) for a reintroduced elk (Cervus canadensis) population in southwestern Virginia, USA and quantify habitat quality by linking home range sizes to the land cover types they contain using linear mixed-effects models. We found mean home range size was largest during late gestation for female elk. Additionally, throughout the year, smaller home ranges were associated with larger proportions of non-forested habitats whereas forested habitats were generally the opposite. However, both presumed poor- and high-quality habitats influenced female elk space use. Our approach revealed spatial variation in habitat quality for a recovering elk herd, demonstrated the importance of non-forested habitats to elk, can guide decisions regarding the location of future elk reintroduction programs, and serve as a model for evaluating habitat quality associated with wildlife reintroductions.

Displacement Effects of Conservation Grazing on Red Deer (Cervus elaphus) Spatial Behaviour

Conservation grazing uses semi-feral or domesticated herbivores to limit encroachment in open areas and to promote biodiversity. However, we are still unaware of its effects on wild herbivores. This study investigates the influence of herded sheep and goats on red deer (Cervus elaphus) spatial behavior by testing three a-priori hypotheses: (i) red deer are expected to avoid areas used by livestock, as well as adjacent areas, when livestock are present, albeit (ii) red deer increase the use of these areas when sheep and goats are temporarily absent and (iii) there is a time-lagged disruption in red deer spatial behavior when conservation grazing practice ends. Using GPS-telemetry data on red deer from a German heathland area, we modelled their use of areas grazed by sheep and goats, using mixed-effect logistic regression. Additionally, we developed seasonal resource selection functions (use-availability design) to depict habitat selection by red deer before, during, and after conservation grazing. Red deer used areas less during conservation grazing throughout all times of the day and there was no compensatory use during nighttime. This effect mostly persisted within 21 days after conservation grazing. Effects on habitat selection of red deer were detectable up to 3000 meters away from the conservation grazing sites, with no signs of either habituation or adaption. For the first time, we demonstrate that conservation grazing can affect the spatio-temporal behavior of wild herbivores. Our findings are relevant for optimizing landscape and wildlife management when conservation grazing is used in areas where wild herbivores are present.

Usually hated, sometimes loved: A review of wild ungulates' contributions to people

Nature's contributions to people (NCP) may be both beneficial and detrimental to humans' quality of life. Since our origins, humans have been closely related to wild ungulates, which have traditionally played an outstanding role as a source of food or raw materials. Currently, wild ungulates are declining in some regions, but recovering in others throughout passive rewilding processes. This is reshaping human-ungulate interactions. Thus, adequately understanding the benefits and detriments associated with wild ungulate populations is necessary to promote human-ungulate co-existence. Here, we reviewed 575 articles (2000-2019) on human-wild ungulate interactions to identify key knowledge gaps on NCP associated with wild ungulates. Wild ungulate research was mainly distributed into seven research clusters focussing on: (1) silvicultural damage in Eurasia; (2) herbivory and natural vegetation; (3) conflicts in urban areas of North America; (4) agricultural damage in Mediterranean agro-ecosystems; (5) social research in Africa and Asia; (6) agricultural damage in North America; (7) research in natural American Northwest areas. Research mostly focused on detrimental NCP. However, the number of publications mentioning beneficial contributions increased after the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services conceptual framework was implemented. Human-ungulate interactions' research was biased towards the Global North and Cervidae, Suidae and Bovidae families. Regarding detrimental NCP, most publications referred to production damage (e.g. crops), followed by biodiversity damage, and material damage (e.g. traffic collisions). Regarding beneficial NCP, publications mainly highlighted non-material contributions (e.g. recreational hunting), followed by material NCP and regulating contributions (e.g. habitat creation). The main actions taken to manage wild ungulate populations were lethal control and using deterrents and barriers (e.g. fencing), which effectiveness was rarely assessed. Increasing research and awareness about beneficial NCP and effective management tools may help to improve the conservation of wild ungulates and the ecosystems they inhabit to facilitate people-ungulate co-existence in the Anthropocene.

Addressing social attitudes toward lethal control of wildlife in national parks

The extraordinary population growth of certain ungulate species is increasingly a concern in agroforestry areas because overabundance may negatively affect natural environments and human livelihoods. However, society may have negative perceptions of killing wildlife to reduce their numbers and mitigate damage. We used an online survey that included a choice experiment to determine Spanish citizens' (n = 190) preferences toward wildlife population control measures related to negative effects of ungulate overabundance (negative impacts on vegetation and other wildlife species and disease transmission to livestock) in 2 agroforestry national parks in Spain. We used latent-class and willingness-to-pay in space models to analyze survey results. Two percent of respondents thought a national park should have no human intervention even if lack of management may cause environmental degradation, whereas 95% of respondents favored efforts to reduce damage caused by overabundant ungulate species. We estimated human well-being losses of survey respondents when sustainable effects of deer overabundance on the environment became unsustainable effects and well-being gains when sustainable effects transitioned to no visible effects. We found that the type of wildlife-control program was a very relevant issue for the respondents; indirect control in which killing was avoided was the preferred action. Sixty-six percent of respondents agreed with the option of hunters paying for culling animals to reduce ungulate impacts rather than management cost coming out of taxes, whereas 19% of respondents were against this option and willing to pay for other solutions in national parks. Our results suggest that killing wildlife in national parks could be a socially acceptable tool to manage overabundance problems in certain contexts, but it could also generate social conflicts.

Seasonal home ranges and habitat selection of three elk (Cervus elaphus) herds in North Dakota

Changes in land use have resulted in range shifts of many wildlife species, including those entering novel environments, resulting in the critical need to understand their spatial ecology to inform ecosystem effects and management decisions. Dispersing elk (Cervus elaphus) were colonizing areas of suitable habitat in the Northern Great Plains, USA, resulting in crop depredation complaints in these areas. Although state resource managers had little information on these elk herds, limited evidence suggested temporal movements into Canada. We collected and analyzed essential information on home range and habitat selection for 3 elk herds residing in North Dakota. We captured 5 adult female elk in each study area, affixed global positioning system collars, and monitored them for 1 year (2016-2017). We estimated diel period, seasonal, and hunting season home ranges using Brownian Bridge Movement Models for each individual. We analyzed habitat selection using multinomial logit models to test for differences in use of land classes, and for departures from proportionate use based on random sampling; our predictor variables included individual elk, diel period, and season. Home ranges differed between the 3 herds, seasons, and diel period; gun and winter season home ranges were both larger than in summer, as was night when compared with day. Female elk generally restricted themselves to cover during the day and entered open areas at night and during winter months. Our results also suggest that elk in our study areas tended to seek more cover, and in the case of our Turtle Mountain study area, some cross into Canada during gun season. Our study provides a better understanding of the spatial ecology of elk in the Northern Great Plains while highlighting the need for enhanced international cooperative management efforts.

Intermediate frequency of aversive conditioning best restores wariness in habituated elk (Cervus canadensis)

In protected areas around the world, wildlife habituate to humans and human infrastructure, potentially resulting in human-wildlife conflict, and leading to trophic disruptions through excess herbivory and disconnection of predators from prey. For large species that threaten human safety, wildlife managers sometimes attempt to reverse habituation with aversive conditioning. This technique associates people as a conditioned stimulus with a negative, unconditioned stimulus, such as pain or fright, to increase wariness and prevent the need for lethal wildlife management. Resistance to aversive conditioning by some habituated individuals often results in more frequent conditioning events by managers, but there are few studies of conditioning frequency with which to evaluate the usefulness of this management response. We evaluated the effect of conditioning frequency on the wariness of elk (Cervus canadensis) by subjecting marked individuals to predator-resembling chases by people over a period of three months. In that time, animals were subjected to conditioning a total of 3, 4, 5, 6, 7, or 9 times which we analyzed as both an ordinal variable and a binary one divided into low (3-5) and high (6-9) conditioning frequencies. We measured wariness before, during, and after the conditioning period using flight response distances from an approaching researcher. During the conditioning period, overall wariness increased significantly for elk in both treatment groups, although the increase was significantly greater in individuals subjected to high conditioning frequencies. However in the post-conditioning period, wariness gains also declined most in the high-frequency group, equating to more rapid extinction of learned behaviour. Across all treatment frequencies, rapid changes in flight responses also characterized the individuals with the lowest wariness at the beginning of the study period, suggesting that individuals with greater behavioural flexibility are more likely to habituate to both people and their attempts to change wariness via aversive conditioning. Together, our results imply that aversive conditioning may be most effective at intermediate frequencies and that its utility might be further increased with proactive assessment of individual personalities in habituated wildlife.

Ambidextrous ungulates have more flexible behaviour, bolder personalities and migrate less

Studies of wildlife have shown consistent individual variation in behavioural plasticity, which affects the rate of adaptation to changing environments. More flexible individuals may thus be more prone to habituation and conflict behaviour, but these applications of personality to wildlife management are little explored. Behavioural lateralization reflects cerebral specialization that may predict diverse expressions of behavioural plasticity. We recorded front-limb biases (i.e. handedness) in wild elk (Cervus canadensis), a species with facultative migration and high rates of habituation inside protected areas. Less lateralized elk responded more strongly to the application of aversive conditioning (predator-resembling chases by humans) by increasing their average flight response distances, but these same animals were also quicker to reduce their flight responses (i.e. habituate) when human approaches were benign. Greater laterality was correlated with, but not completely predicted by, bolder personalities, which we quantified via five correlated behavioural metrics. Lastly, lateralized elk were three times more likely to migrate, whereas less lateralized animals were similarly likely to remain near humans year-round. Lateralized behaviours can provide insight into behavioural flexibility enabling certain individuals to more quickly adapt to human-disturbed landscapes, and offer an especially productive arena for collaborative work by behaviourists, conservation biologists and wildlife managers.

A systematic review of the impacts and management of introduced deer (family Cervidae) in Australia

Deer are among the world’s most successful invasive mammals and can have substantial deleterious impacts on natural and agricultural ecosystems. Six species have established wild populations in Australia, and the distributions and abundances of some species are increasing. Approaches to managing wild deer in Australia are diverse and complex, with some populations managed as ‘game’ and others as ‘pests’. Implementation of cost-effective management strategies that account for this complexity is hindered by a lack of knowledge of the nature, extent and severity of deer impacts. To clarify the knowledge base and identify research needs, we conducted a systematic review of the impacts and management of wild deer in Australia. Most wild deer are in south-eastern Australia, but bioclimatic analysis suggested that four species are well suited to the tropical and subtropical climates of northern Australia. Deer could potentially occupy most of the continent, including parts of the arid interior. The most significant impacts are likely to occur through direct effects of herbivory, with potentially cascading indirect effects on fauna and ecosystem processes. However, evidence of impacts in Australia is largely observational, and few studies have experimentally partitioned the impacts of deer from those of sympatric native and other introduced herbivores. Furthermore, there has been little rigorous testing of the efficacy of deer management in Australia, and our understanding of the deer ecology required to guide deer management is limited. We identified the following six priority research areas: (i) identifying long-term changes in plant communities caused by deer; (ii) understanding interactions with other fauna; (iii) measuring impacts on water quality; (iv) assessing economic impacts on agriculture (including as disease vectors); (v) evaluating efficacy of management for mitigating deer impacts; and (vi) quantifying changes in distribution and abundance. Addressing these knowledge gaps will assist the development and prioritisation of cost-effective management strategies and help increase stakeholder support for managing the impacts of deer on Australian ecosystems.

Juxtaposition between host population structures: implications for disease transmission in a sympatric cervid community

Sympatric populations of phylogenetically related species are often vulnerable to similar communicable diseases. Although some host populations may exhibit spatial structure, other hosts within the community may have unstructured populations. Thus, individuals from unstructured host populations may act as interspecific vectors among discrete subpopulations of sympatric alternate hosts. We used a cervid-bovine tuberculosis (Mycobacterium bovis) system to investigate the landscape-scale potential for bovine tuberculosis transmission within a nonmigratory white-tailed deer (Odocoileus virginianus) and elk (Cervus canadensis) community. Using landscape population genetics, we tested for genetic and spatial structure in white-tailed deer. We then compared these findings with the sympatric elk population that is structured and which has structure that correlates spatially and genetically to physiognomic landscape features. Despite genetic structure that indicates the white-tailed deer population forms three sympatric clusters, the absence of spatial structure suggested that intraspecific pathogen transmission is not likely to be limited by physiognomic landscape features. The potential for intraspecific transmission among subpopulations of elk is low due to spatial population structure. Given that white-tailed deer are abundant, widely distributed, and exhibit a distinct lack of spatial population structure, white-tailed deer likely pose a greater threat as bovine tuberculosis vectors among elk subpopulations than elk.

Effects of gonadotropin-releasing hormone immunization on reproductive function and behavior in captive female Rocky Mountain elk (Cervus elaphus nelsoni)

Fertility control is a potential method for managing overabundant wildlife populations; however, current technology is limited by duration of treatment efficacy and unacceptable side effects. The objective of this study was to determine the efficacy of a single immunization with gonadotropin-releasing hormone (GnRH) vaccine to suppress reproductive function in pregnant female elk and to evaluate potential behavioral and pathological side effects of treatment. Eighteen captive adult female elk were randomly allocated to one of two experimental groups. Ten females were administered a conjugated and adjuvanted GnRH vaccine intramuscularly, and eight elk received an adjuvant sham vaccine without conjugated GnRH. We compared success of existing pregnancy, neonatal survival, subsequent fertility, reproductive behavior rates, and side effects of treatment between January 2006 and January 2010. The GnRH vaccination did not affect existing pregnancy or calf survival during the year that it was applied; however, it reduced the proportion of pregnant females for 3 yr. Male precopulatory behavior rates exhibited toward GnRH-vaccinated females tended to be greater than those directed at sham-vaccinated females during the second half of the breeding season, when GnRH vaccinates continued to be proceptive. Strong immune and inflammatory responses, including robust GnRH antibody concentrations in GnRH vaccinates, and sterile pyogranulomatous injection site abscesses in both groups, were consistent with vaccination. In conclusion, this GnRH vaccine resulted in prolonged, albeit reversible, impairment of fertility, and is associated with extended reproductive behaviors and partial suppression of hypothalamic-pituitary-gonadal axis function in captive female elk.

Interdisciplinary approaches for the management of existing and emerging human - wildlife conflicts

Human–wildlife conflicts are increasing throughout the world, principally due to a combination of human population growth, increased pressure on land and natural resources and climate change. Many human–wildlife conflicts stem from differences in objectives between various stakeholder groups, especially where the wildlife in question is a resource that can be exploited for economic or cultural benefit, or where the conservation of wildlife is at odds with human population growth or development pressure. Conflicts can be exacerbated by an incomplete understanding of their causes and/or inappropriate intervention measures. Many traditional forms of intervention are also subject to increasing scrutiny and criticism from society. Here, we highlight the potential strategic benefits that can be made by an interdisciplinary approach to human–wildlife conflict situations, by integrating knowledge and understanding across the natural and social sciences. We also stress the potential tactical benefits from combining new approaches to management with more traditional ones. We emphasise the potential contribution of more recent developments in decision-making under conditions of limited data availability and uncertainty. Finally, we recommend that monitoring should play a more prominent role, both in assessing the role of stakeholder engagement in participatory decision-making and in contributing to the evidence base that will allow competing hypotheses about specific systems to be evaluated in an iterative manner.