Home Range Establishment Research Articles

Role of social structure in establishment of an invasive large mammal after translocation.

Data on the movement behavior of translocated wild pigs is needed to develop appropriate response strategies for containing and eliminating new source populations following translocation events. We conducted experimental trials to compare the home range establishment and space-use metrics, including the number of days and distance traveled before becoming range residents, for wild pigs translocated with their social group and individually. We found wild pigs translocated with their social group made less extensive movements away from the release location and established a stable home range ~5 days faster than those translocated individually. We also examined how habitat quality impacted the home range sizes of translocated wild pigs and found wild pigs maintained larger ranges in areas with higher proportion of low-quality habitat. Collectively, our findings suggest translocations of invasive wild pigs have a greater probability of establishing a viable population near the release site when habitat quality is high and when released with members of their social unit compared to individuals moved independent of their social group or to low-quality habitat. However, all wild pigs translocated in our study made extensive movements from their release location, highlighting the potential for single translocation events of either individuals or groups to have far-reaching consequences within a much broader landscape beyond the location where they are released. These results highlight the challenges associated with containing populations in areas where illegal introduction of wild pigs occurs, and the need for rapid response once releases are identified. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Habitat quality influences trade-offs in animal movement along the exploration–exploitation continuum

To successfully establish itself in a novel environment, an animal must make an inherent trade-off between knowledge accumulation and exploitation of knowledge gained (i.e., the exploration–exploitation dilemma). To evaluate how habitat quality affects the spatio-temporal scale of switching between exploration and exploitation during home range establishment, we conducted experimental trials comparing resource selection and space-use of translocated animals to those of reference individuals using reciprocal translocations between habitat types of differing quality. We selected wild pigs (Sus scrofa) as a model species to investigate hypotheses related to the movement behavior of translocated individuals because they are globally distributed large mammals that are often translocated within their introduced range to facilitate recreational hunting. Individuals translocated to higher quality habitat (i.e. higher proportions of bottomland hardwood habitats) exhibited smaller exploratory movements and began exploiting resources more quickly than those introduced to lower quality areas, although those in lower-quality areas demonstrated an increased rate of selection for preferred habitat as they gained knowledge of the landscape. Our data demonstrate that habitat quality mediates the spatial and temporal scale at which animals respond behaviorally to novel environments, and how these processes may determine the success of population establishment.

The effect of oil palm-dominated landscapes on the home range and distribution of a generalist species, the Asian water monitor.

The Asian water monitor lizard, Varanus salvator, is one of the largest predators in Southeast Asia which persists in human‐dominated landscapes and, as such, is a suitable model to understand the behavioral plasticity of generalists in anthropogenic landscapes. We used Local Convex Hull with adaptive algorithm to estimate the home range size of 14 GPS‐tagged individuals, followed by a MAXENT approach and community prey composition to understand the habitat preferences within the landscape. We estimated larger home ranges in forest than in oil palm plantations, as well as a larger diversity and abundance of mammals. Core home ranges were always linked to water bodies. However, the use of underproductive oil palm, freshwater swamp forest, and degraded forest by monitor lizards were higher than other kind of vegetation. This suitable habitat is proportionally larger in forest (73.7%) than in oil palm plantations (39.6%). Generalized estimation equation models showed that, while full home range size was negatively associated with the abundance of mammals, core areas depicted a positive association with mammal abundance, as well as with the proportion of suitable habitat within the home range. Besides having smaller home ranges in oil palm plantations, our findings suggest that limited suitable habitat availability forces the Asian water monitor lizard's population to establish only one or very few core areas. Contrastingly, under the protection of forest, they have more core areas, widely dispersed within larger home ranges. We conclude that regardless the plasticity of the species, human‐dominated landscapes are altering natural patterns of home range establishment in the monitor lizard's population, creating a potential ecological trap where conditions may not remain favorable for them in the long run. A deeper understanding of the ecological implications on the species and the prey community is advisable.

Factors Influencing the Postrelease Movements of Translocated Fishers: Implications for Translocation Success

Abstract Long-distance, postrelease movements of translocated wildlife can be a key factor limiting translocation success. Yet, for many species, we have little or no understanding of factors that influence postrelease movements. Translocations have been important for recovering fisher Pekania pennanti populations across the southern portion of their North American range. However, little is known about the postrelease movements of translocated fishers and how these movements may be influenced by demographic or translocation-process factors. To restore fishers in Washington State, we moved 90 fishers from central British Columbia and released them at nine sites in the Olympic Fisher Recovery Area on the Olympic Peninsula of Washington from 2008 to 2010. We evaluated postrelease movements of 48 fishers to determine both the distance and duration of movements prior to home range establishment. Fishers moved extensively following their release. Multimodel selection indicated a high level of support for the hypothesis that postrelease movements differed by fisher sex and age; whereas, year of release had no apparent effect on movements, and release date had only a marginal influence on movements. Mean distance (±95% CI) from a release site to a home range was greater for adult males (62.0 ± 19.6 km) than for juvenile males (31.4 ± 16.0 km), adult females (30.9 ± 21.1 km), and juvenile females (29.0 ± 13.5 km). Mean number of days from release until home range establishment was similar for the sexes; however, the variance in movement duration was greater for females. Twenty-six of 27 females established home ranges over an 11-mo period (December–October), while 19 of 21 males did so within a 4-mo period (April–July). Mean home range sizes differed between males (128.3 ± 21.1 km2) and females (63.5 ± 9.0 km2) and were among the largest reported for the species. A greater proportion of females (18 of 27; 67%) than males (8 of 21; 38%) established home ranges within or partially within the recovery area. Six females left a previously established home range during the breeding season, presumably to find breeding males. Given the large distances that fishers can move following release, translocation success could be furthered by releasing individuals at fewer sites in the interior of large reintroduction areas to facilitate greater exposure to a recovery area and greater opportunity to interact with conspecifics and potential mates.

Finding a Home: Stopping Theory and Its Application to Home Range Establishment in a Novel Environment

Familiarity with the landscape increases foraging efficiency and safety. Thus, when animals are confronted with a novel environment, either by natural dispersal or translocation, establishing a home range becomes a priority. While the search for a home range carries a cost of functioning in an unfamiliar environment, ceasing the search carries a cost of missed opportunities. Thus, when to establish a home range is essentially a weighted sum of a two-criteria cost-minimization problem. The process is predominantly heuristic, where the animal must decide how to study the environment and, consequently, when to stop searching and establish a home range in a manner that will reduce the cost and maximize or at least satisfice its fitness. These issues fall within the framework of optimal stopping theory. In this paper we review stopping theory and three stopping rules relevant to home range establishment: the best-of-n rule, the threshold rule, and the comparative Bayes rule. We then describe how these rules can be distinguished from movement data, hypothesize when each rule should be practiced, and speculate what and how environmental factors and animal attributes affect the stopping time. We provide a set of stopping-theory-related predictions that are testable within the context of translocation projects and discuss some management implications.

Long-distance dispersal and home range establishment by a female sub-adult tiger (Panthera tigris) in the Panna landscape, central India

Long-distance dispersal and home range establishment by a female sub-adult tiger (Panthera tigris) in the Panna landscape, central India

An Ad Hoc Translocation of Urban Eastern Box Turtles (Terrapene carolina carolina)

As the human population grows and wildlife habitat is lost, managers are increasingly reliant on hands-on management strategies such as translocation. Without much evidence suggesting success, moving a species or population from one location to another has been controversial for some taxa, especially for wildlife in urban areas. Here, in an ad hoc translocation of Terrapene carolina carolina (Eastern Box Turtle) in Washington, DC, we describe movements of 10 translocated turtles from 2011 to 2014, with 4 settling into apparent short-term home ranges and 6 requiring repeated relocation. Our study population was small, but results suggested that home-range establishment may occur with repositioning individuals post-release. Translocations should not proceed without sufficient investment from managers to carry out long-term monitoring of released individuals.

Space use by giant anteaters (Myrmecophaga tridactyla) in a protected area within human-modified landscape.

Spatial ecology data are essential for conservation purposes, especially when extinction risk is influenced by anthropogenic actions. Space use can reveal how individuals use the habitat, how they organize in space, and which components are key resources for the species.We evaluated the space use and multiscale habitat selection of giant anteaters (Myrmecophaga tridactyla), a vulnerable Neotropical mammal, in a Cerrado site within a human‐modified landscape in southeastern Brazil.We used GPS transmitters to track eight anteaters in the wild. With the resulting dataset, we estimated home range and core‐area sizes and then used two overlap indexes. We assessed habitat selection by compositional analysis and analyzed events of spatio‐temporal proximity.The average Brownian bridge kernel estimate of home range size was 3.41 km2 (0.92–7.9). Regarding home range establishment, five individuals showed resident behavior. Males (n = 4) had larger home ranges and were more active than females (n = 4). Despite the spatial overlap of home range (above 40% in four dyads), maximum temporal space sharing was 18%. Giant anteaters were found in proximity. Habitat selection favored savanna, and exotic timber plantation was always avoided. Roads and built‐up areas were selected secondarily at the landscape level.The selection of anthropogenic sites denotes behavioral plasticity regarding modified habitats. However, the high selectivity for savanna, at all levels, demonstrates a high dependence on natural habitats, which provide the necessary resources for the species. The recurrent proximity of male–to‐female anteaters may indicate reproductive behavior, which is essential for maintaining this isolated population.

Wolf habitat selection when sympatric or allopatric with brown bears in Scandinavia

Habitat selection of animals depends on factors such as food availability, landscape features, and intra- and interspecific interactions. Individuals can show several behavioral responses to reduce competition for habitat, yet the mechanisms that drive them are poorly understood. This is particularly true for large carnivores, whose fine-scale monitoring is logistically complex and expensive. In Scandinavia, the home-range establishment and kill rates of gray wolves (Canis lupus) are affected by the coexistence with brown bears (Ursus arctos). Here, we applied resource selection functions and a multivariate approach to compare wolf habitat selection within home ranges of wolves that were either sympatric or allopatric with bears. Wolves selected for lower altitudes in winter, particularly in the area where bears and wolves are sympatric, where altitude is generally higher than where they are allopatric. Wolves may follow the winter migration of their staple prey, moose (Alces alces), to lower altitudes. Otherwise, we did not find any effect of bear presence on wolf habitat selection, in contrast with our previous studies. Our new results indicate that the manifestation of a specific driver of habitat selection, namely interspecific competition, can vary at different spatial-temporal scales. This is important to understand the structure of ecological communities and the varying mechanisms underlying interspecific interactions.

Home range establishment and the mechanisms of philopatry among female Bornean orangutans (Pongo pygmaeus wurmbii) at Tuanan

Female orangutans exhibit natal philopatry, living in stable home ranges that overlap with those of their maternal relatives. Using data collected from 2003 to 2017 at Tuanan in Central Kalimantan, Indonesia, we take a longitudinal approach to better understand the mechanisms of female philopatry and the factors that influence the home range establishment process of young female orangutans (Pongo pygmaeus wurmbii). Data on movement and sociality were collected during nest-to-nest focal follows of individual orangutans; four young nulli/primiparous females, their three multiparous mothers, and seven other unrelated adult females living in the same area. Our results show that a young female goes through an ‘exploration phase’, beginning when she is an independent immature and lasting through her adolescence, characterized by an increase in home range size and distance travelled each day. This exploration is facilitated by high resource availability and association with adult males. A young female maintains a high degree of overlap with her natal range but gradually decrease the degree of overlap with her mother’s concurrent range. By the time she is a sexually active adolescent, a young female and her mother share as much overlap as a young female does with other related adult females, although she continues to associate more with her mother than with them, even after the birth of her first offspring. Our findings indicate that the high habitat productivity and high orangutan population density of Tuanan lead to a high degree of life-time site fidelity and overlap among maternal kin. The mechanisms of philopatry and the process of home range establishment among solitary animals with slow life histories are difficult to study and poorly understood for most species. We investigated this process among female Bornean orangutans, using a unique long-term data set comprising 15 years of social and spatial data. We analysed changes in the ranging and association patterns of young female orangutans as they developed, matured and became mothers. We found that females went through a post-dependence phase of exploration characterized by an increase in range size and day journey length, and then settled into home ranges that overlapped highly with their mothers and other female kin, though they associated preferentially with their mothers. Our results illuminate the extreme long-term site fidelity of these female orangutans and emphasize the ecological and social importance of female philopatry among orangutans.

Management Background and Release Conditions Structure Post-release Movements in Reintroduced Ungulates

One of the greatest challenges in restoring threatened species to the wild is insufficient knowledge about their habitat requirements and movement ecology. This is especially true for wide-ranging species such as the scimitar-horned oryx (Oryx dammah). Once widespread across Sahelo-Saharan grasslands, oryx were declared Extinct in the Wild in 1999. Here, we integrate GPS/satellite tracking, remote sensing, and gspatial analyses into a large reintroduction project to assess how captive-born oryx respond to wild conditions. We monitored two groups of oryx, reared under different management approaches and released in different seasons, for 12 months after release. Our study provides the first movement trajectories and home range estimates ever recorded for this species. We assessed how captive management methods, release timing, and local environmental conditions during and after release affected oryx movement behavior, survival, and fecundity. Post-release dispersal ranged from 2-90 km. Oryx raised under semi-free ranging conditions, which experienced a long acclimation period, and released during the wet season (“ranging”), moved 40-60 km from the release site. In contrast, oryx raised in smaller pens, with a short acclimation period, and released during the dry season (“penned”), remained within 5-25 km. We expected oryx movements after release to represent tradeoffs between risky, energetically expensive exploratory movements, and optimal resource exploitation. Ranging oryx exhibited this predicted pattern of exploration followed by home range establishment, while penned oryx explored less novel terrain and continuously returned to the release site where supplemental food and water were available. Ranging oryx also exhibited seasonal shifts in movement patterns, while penned oryx simply reduced overall movement. Our results demonstrate that captive management and environmental conditions at release strongly influence the rate and extent to which reintroduced oryx disperse and adapt to wild conditions. We also show that – in contrast to previous studies – longer acclimation periods do not always lead to greater site fidelity. Finally, our findings demonstrate the importance of tracking the largest possible proportion of reintroduced individuals in order to: (1) accurately record post-release behaviors and vital rates of a reintroduced population and (2) adaptively evaluate pre- and post-release management actions to improve conservation outcomes.

Shedding light on a cryptic macropodid: home ranges and habitat preferences of translocated western brush wallabies (Notamacropus irma)

A salvage translocation of western brush wallabies (Notamacropus irma (Jourdan, 1837)) was a condition of approval to build a new runway at Jandakot Airport, Western Australia. Since little is known about this endemic Western Australian species, the translocation presented a valuable opportunity to gain information on the species after release into Harry Waring Marsupial Reserve, a 260-ha reserve where these animals had been recorded previously. We aimed to gain information on the biology and ecology of the species and follow the movement of individuals tracked with Global Positioning System (GPS) collars over six months to determine their short-term survival, home-range establishment, overlap in home range between individuals, and habitat utilisation in the reserve. Weekly mean home-range estimates did not differ between males (10.0±9.7 (s.d.) ha, 95% KDE, n=6) and females (12.1±6.1 (s.d.) ha, 95% KDE, n=5) (P=0.473). Some males had 67–70% overlap in home ranges with some females, but substantial distances maintained between individuals (from 123±110m to 292±303m) confirmed the solitary nature of the species. Western brush wallabies preferred Banksia spp. woodlands, possibly due to the availability of canopy cover, and some specific understorey associations, such as Hibbertia hypericoides, that form part of their diet. Our study highlighted the importance of understanding the home-range establishment and vegetation preferences of translocated animals that will inform the planning of future translocations.

Common pastures are important refuges for a declining passerine bird in a pre-alpine agricultural landscape

Agricultural landscapes play an important role in biodiversity conservation. The Tree Pipit (Anthus trivialis) was once a widespread breeding bird in European farmlands. Today, however, its numbers are sharply declining in most European countries. The aim of our study was to compare territory densities of Tree Pipits in common pastures and control plots in the surrounding pre-alpine agricultural landscape in southern Bavaria (Germany). Additionally, we determined the drivers of territory and home-range establishment in Tree Pipits. Habitat composition in common pastures and control plots reflected distinct differences in land-use intensity. Common pastures had larger areas of nutrient-poor habitats and higher landscape diversity compared to control plots. In line with this, we detected a clear response of Tree Pipits to differences in habitat composition. Territories were nearly exclusively found in common pastures. Within the common pastures, Tree Pipits preferred those parts that had higher landscape diversity and, additionally, at the territory scale, larger areas of groups of trees. The common pastures are important refuges for the threatened Tree Pipit in the pre-alpine agricultural landscape of the study area. In contrast to the control plots, the common pastures provided (i) sufficient suitable song posts and (ii) heterogeneous vegetation with appropriate nesting sites and a high availability of arthropod food resources. Our study corroborates findings from other studies across Europe highlighting the prime importance of traditionally used wood pastures for the Tree Pipit, and for biodiversity in general.

Habitat selection of European pine marten in Central Italy: from a tree dependent to a generalist species

Studies at small spatial scale are often fundamental to highlight the behavioural plasticity of a species and thus have important implications for conservation planning, in particular for species usually considered as habitat specialists. We investigated second-order habitat selection of the European pine marten in an area dominated by deciduous oak forest and open fields in central Italy, by radio-tracking 16 pine martens (eight males, eight females). Pine martens placed home ranges in areas with more open field than in the study area, whereas woodland (oak and conifer forests) comprised a smaller portion of the home range than predominant forest character of the studied area. Although the presence of the species in the open habitats has been documented, to our knowledge, our results provide the first evidence of home range establishment in this cover type by pine marten at population level. The combination of low predation risk and high availability of resources could allow pine martens to occupy open fields in our study area. We highlighted different individual strategies of habitat selection, with some individuals placing home ranges in areas with high forest coverage while others occupying open areas. We found no effects of sex and body condition on habitat selection, and this could indicate that in the study area, both forested and non-forested cover types, such as open fields, shrub and anthropic areas, can provide adequate food, overhead cover and resting sites for all individuals. Pine marten ability to occupy open fields seems thus more related to the behavioural flexibility of the species, rather than to the need to supplement dens and forage from complementary lower quality habitat. The high quality of the Mediterranean continental area studied could also explain the selection of open areas by the pine marten. Our results offer useful information on pine marten ecology and may be helpful for conservation management of this species in southern Europe.

Home range establishment and utilization by reintroduced lions (Panthera leo) in a small South African wildlife reserve

Understanding of animal spatial behavior is essential for informed management decisions. In southern Africa, reintroduction of lions (Panthera leo) to small reserves (<1000 km2 ) has increased since the early 2000s, however studies on their ranging behavior in these enclosed systems remain lacking. We applied Time Local Convex Hull (T-LoCoH) methods to study the home range establishment and utilization of 11 lions reintroduced to Dinokeng Game Reserve, South Africa, during 2011 through 2014. Lions established home ranges close to their release sites and during the following 3 years their home range sizes continued to increase, but in each individual case the size remained smaller than half of the reserve area (<70 km2 ). Space use strategies differed between the core and the entire home range, with higher frequency of visits found in core areas. Exceptionally high rates (>60 separate visits) around the largest dam and along rivers suggest the importance of water and its surrounding vegetation in the lions' space utilization pattern. The home range size did not differ with season or sex of the individuals, whereas shifts in locations of home ranges revealed differences in the response of the 2 sexes to territorial conflicts and management interventions. Our study shows a dynamic home range utilization pattern and highlights the importance of both fine-scale space use patterns (frequency and duration of visits) and broad-scale home range changes in understanding the ranging behavior of reintroduced animals.

Summer use of the tidal freshwaters of the River Seine by three estuarine fish: Coupling telemetry and GIS spatial analysis

Acoustic telemetry and GIS-based spatial analysis were used to investigate the summer habitat use and movement patterns of three fish species in the tidal freshwaters of the Seine estuary (France). Experimental displacement of tagged individuals of thin-lipped grey mullet (Liza ramada), European eel (Anguilla anguilla), and common bream (Abramis brama) were conducted to test for their spatial fidelity and home range establishment. Most tagged individuals (95%) successfully returned to their previously occupied capture site, showing spatial homing abilities. The studied upstream tidal freshwater segment of the Seine estuary was regularly used by grey mullet as a part of its larger summer home range, while European eel and common bream were resident in this segment. The fidelity of eel to small nocturnal refuges and the regular use of intertidal waterbodies at high tide by grey mullet and bream suggested that they possess a capacity of acquiring spatial memory of habitats in a fluctuating environment. Importantly, the scale of movements travelled by each species was positively related to tidal phase. Grey mullet and bream, both visual feeders, exhibited short-term tidal movements to known habitats, providing food resources and contiguous resting habitat suggesting that they have shown behavioural strategies adaptive to fluctuating environments. Eel, in contrast, was found to have a different strategy strongly related to diel dynamics: it stayed in subtidal habitats rich in refuges that remained available at low tide. The results of this study emphasize the importance of restoring intertidal waterbodies and the relevance of considering the availability of adjacent subtidal habitats providing refuge at low tides.

Movement and home range characteristics of reintroduced tiger (Panthera tigris) population in Panna Tiger Reserve, central India

Reintroduction of the tiger (Panthera tigris) has become imperative to address the extinction crisis and, it also provides new knowledge of the species biology as to how these animals explore and utilize new environments. We studied six reintroduced tigers and three of their offsprings in Panna Tiger Reserve, central India, focusing on exploration strategy, movement characteristics and spatio-temporal home range patterns. It was found that the release site had no influence on home range selection by the reintroduced tigers, regardless of the release method (soft or hard release) and origin (wild caught or raised in captivity). Although there was a high rate of initial movement, these animals exhibited strong site fidelity and territoriality subsequently. Mean (±SD) annual home ranges of male and female tigers were 132.7 km2 ± 9.0 and 73.6 km2 ± 9.6, respectively, and did not differ significantly across seasons. The home range sizes of males were among the largest in India and was also marginally larger for females. Comparison with previous telemetry study on historic tiger population in the same site suggests that the reintroduced animals behaved almost exactly the same way as that of native populations, offering support for reintroduction strategies which look to restore not only the species population but also ecosystem functions. The exploratory strategy and subsequent home range establishment by the reintroduced tigers offer novel insights on species behaviour in a new environment, with implication for future conservation strategies that consider translocation-based recovery of tiger populations in the range countries.

Effects of temporary captivity on ranging behaviour in urban red foxes (Vulpes vulpes)

Temporary removal of wild animals from a resident territory has the potential to markedly impact subsequent ranging behaviour, and may negatively affect post-release welfare and survival. Admission of sick or injured wildlife into temporary captivity (termed ‘rehabilitation’) is a common practice in the UK. However, post-release monitoring of rehabilitated animals is unusual or restricted to recording survival rates over limited time periods. As part of a wider study of urban fox behaviour, we employed an experimental approach to compare the ranging behaviour of seven rehabilitated and 13 wild-caught ‘control’ urban red foxes using GPS tracking. Foxes were tracked over a two-year period for an average of 48 nights, and seasonal and sex-related effects were controlled for via inclusion in statistical models. Three of the five movement parameters we investigated were irregular for the rehabilitated animals, relative to controls. These were: reduced likelihood of establishing a stable home range (42.9/57.1% of rehabilitated foxes versus 84.6% of controls); larger home ranges (Kruskal Wallis test, χ2=7.517, df=1, p<0.01); and further distance travelled from release point, as measured by overlap between initial and final home ranges (Linear regression, F1,12=4.755, df=1, P<0.05). Females moved greater distances than males overall, and foxes from both groups travelled further in spring, and delayed home range establishment in summer. However, these results were skewed by the movements of two apparently cooperatively breeding wild-caught vixens. Our data provide evidence of territorial displacement of rehabilitated foxes on release. We discuss the welfare implications of this finding.

Translocation of a top-order carnivore: tracking the initial survival, spatial movement, home-range establishment and habitat use of Tasmanian devils on Maria Island

The Tasmanian devil (Sarcophilus harrisii) is a carnivorous marsupial threatened with extinction from the emergence of Devil Facial Tumour Disease. The establishment of ex situ populations is a key management action for the species. We examined the initial survival, movement pattern, home range, and habit use of six devils from a total of 15 individuals translocated to Maria Island (south-east Tasmania). A total of 14 devils (93%) survived the initial monitoring phase within this study (122 days after translocation). The maximum and minimum distance recorded during one night was 21.73 km (range = 14.12–25.40 km) and 1.94 km (range = 0.07–7.71 km), respectively, while the average nightly distance travelled varied significantly (range = 7.24–13.07 km) between individuals. Short-term home-range size (90% kernel) varied from 936 to 3501 ha, with an average of 2180 (±836) ha for all devils. The habitat preference of devils on Maria Island shows a positive association with agricultural and urban habitats, and an avoidance of wet eucalypt forest. The home range and habitat associations may change as competitive pressures increase with population growth; however, this initial research indicates that translocation as a management action is a powerful tool for the establishment of ex situ populations, assisting in the continued conservation of this species.

Using a Data-Constrained Model of Home Range Establishment to Predict Abundance in Spatially Heterogeneous Habitats

Mechanistic modelling approaches that explicitly translate from individual-scale resource selection to the distribution and abundance of a larger population may be better suited to predicting responses to spatially heterogeneous habitat alteration than commonly-used regression models. We developed an individual-based model of home range establishment that, given a mapped distribution of local habitat values, estimates species abundance by simulating the number and position of viable home ranges that can be maintained across a spatially heterogeneous area. We estimated parameters for this model from data on red-backed vole (Myodes gapperi) abundances in 31 boreal forest sites in Ontario, Canada. The home range model had considerably more support from these data than both non-spatial regression models based on the same original habitat variables and a mean-abundance null model. It had nearly equivalent support to a non-spatial regression model that, like the home range model, scaled an aggregate measure of habitat value from local associations with habitat resources. The home range and habitat-value regression models gave similar predictions for vole abundance under simulations of light- and moderate-intensity partial forest harvesting, but the home range model predicted lower abundances than the regression model under high-intensity disturbance. Empirical regression-based approaches for predicting species abundance may overlook processes that affect habitat use by individuals, and often extrapolate poorly to novel habitat conditions. Mechanistic home range models that can be parameterized against abundance data from different habitats permit appropriate scaling from individual- to population-level habitat relationships, and can potentially provide better insights into responses to disturbance.