Predictors Of Space Use Research Articles

Influence of Landscape Characteristics on Hunter Space Use and Success

ABSTRACTSport hunting of ungulates is a predominant recreational pursuit and the primary tool for managing their populations in North America and beyond, given its influence on ungulate distributions, social organization, and population performance. Similarly, land management, such as motorized vehicle access, influences ungulate distributions during and outside hunting seasons. Although research on ungulate responses to hunting and land use is widespread, knowledge gaps persist about space use of hunters and what landscape features discriminate among hunt types and between successful and unsuccessful hunters. We used telemetry location data from hunters (n = 341) to estimate space use from 2008–2013 during 3 types of controlled, 5‐day hunts for antlered mule deer (Odocoileus hemionus) and elk (Cervus canadensis) in northeastern Oregon, USA: archery elk, rifle deer, and rifle elk. To evaluate space use, we developed utilization distributions for each hunter, created core areas (50% contours) for groups of hunters, and derived several metrics of space‐use overlap between successful and unsuccessful hunters. We also modeled predictors of space use using resource utilization functions with beta regression and stepwise model building. Hunter space use was compressed, with even the largest core area (unsuccessful rifle elk hunters) encompassing <16% (1,178 ha) of the area. We found strong similarities in space use of rifle hunters compared to archers, and core areas of successful hunters were markedly smaller than those of unsuccessful hunters (e.g., = 104 ha vs. 681 ha, respectively, for archers). Percentage cover and distance from open roads were the most consistent covariates in the 6 final models (successful vs. unsuccessful for each of 3 hunts) but with different signs. For example, predicted use of archery and rifle elk hunters increased with cover but decreased for rifle deer hunters. Although the same covariates were in the final models for unsuccessful and successful rifle elk hunters, their negligible spatial overlap suggested they sought those features in different locales, a pattern also documented for rifle deer hunters. Our models performed well (Spearman's rank correlation coefficients = 0.99 for 5 of 6 models), reflecting their utility for managing hunters and landscapes. Our results suggest that strategic management of open roads and forest cover can benefit managers seeking to balance hunter opportunity and satisfaction with harvest objectives, especially for species of special concern such as mule deer, and that differences in space use among hunter groups should be accounted for in hunting season designs. © 2021 The Wildlife Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Disentangling the biotic and abiotic drivers of emergent migratory behavior using individual-based models

Understanding the drivers of movement, migration and distribution of individuals is important for insight into how species will respond to changing environmental conditions. Both abiotic and biotic factors are thought to influence migratory behavior, but their relative roles are difficult to disentangle. For migratory marine predators, both temperature and prey availability have been shown to be significant predictors of space use, though often researchers rely on physical proxies due to the lack of data on dynamic prey fields. We generated spatially explicit individual-based movement models to evaluate the relative roles of abiotic (sea surface temperature; SST) and biotic (prey availability) factors in driving blue whale (Balaenoptera musculus) movement decisions and migratory behavior in the eastern North Pacific. Using output from a lower trophic ecosystem model coupled with a regional ocean circulation model, we parameterized a blue whale movement model that explicitly incorporates prey fields in addition to physical proxies. A model using both SST and prey data reproduced blue whale foraging behavior including realistic timing of latitudinal migrations. SST- and prey-only population models demonstrated important independent effects of each variable. In particular, the SST-only model revealed that warm temperatures limited krill foraging opportunities but failed to drive seasonal foraging patterns, whereas the prey-only model revealed more realistic seasonal and interannual differences in foraging behavior. Our individual-based movement model helps elucidate the mechanisms underlying migration and demonstrates how fine-scale individual decision-making can lead to emergent migratory behavior at the population level. Moreover, determining the relative effects of the physical environment and prey availability on the movement decisions of threatened species is critical to understand how they may respond to changing ocean conditions.

Habitat Selection by Northern Pygmy-Owls in the Rocky Mountains

Elucidating the differential use of resources by animals is fundamental to both understanding ecological processes and making informed conservation decisions. Such information is particularly important for poorly studied species that may be dependent upon heavily exploited resources. We examine habitat selection of the Northern Pygmy-Owl (Glaucidium gnoma), which is thought to depend upon mature forests, but for which information on habitat use is scant. We conducted our study in northern Idaho and western Montana, and used the synoptic model of space use. We obtained sufficient location data to include 27 radio-tagged owls in the study (16 in Idaho and 11 in Montana). To evaluate habitat selection, we developed 36 models in Idaho and 24 models in Montana, each with different combinations of habitat covariates hypothesized to influence Northern Pygmy-Owl space use. Covariates representing larger tree size were statistically significant ( ≥ 3.01, t ≥ 2.7, P ≤ 0.02) predictors of space use in the best-supported population-level models in both Idaho and Montana. In addition, the distance-to-stream covariate was a statistically significant ( = −3.60, t = −3.3, P = 0.005) predictor of the probability of use in the best-supported population-level model in Idaho, but not in the best-supported Montana model ( = −0.08, t =0.03, P = 0.98). Owls selected forested areas with larger tree sizes and (in Idaho) selected areas closer to stream courses. Differences between the two study areas in the apparent importance of stream proximity to habitat selection may reflect differences in timber harvest practices and the amount of coniferous vegetation; however, this hypothesis should be addressed with additional research.

Fine-scale harbour seal usage for informed marine spatial planning

High-resolution distribution maps can help inform conservation measures for protected species; including where any impacts of proposed commercial developments overlap the range of focal species. Around Orkney, northern Scotland, UK, the harbour seal (Phoca vitulina) population has decreased by 78% over 20 years. Concern for the declining harbour seal population has led to constraints being placed on tidal energy generation developments. For this study area, telemetry data from 54 animals tagged between 2003 and 2015 were used to produce density estimation maps. Predictive habitat models using GAM-GEEs provided robust predictions in areas where telemetry data were absent, and were combined with density estimation maps, and then scaled to population levels using August terrestrial counts between 2008 and 2015, to produce harbour seal usage maps with confidence intervals around Orkney and the North coast of Scotland. The selected habitat model showed that distance from haul out, proportion of sand in seabed sediment, and annual mean power were important predictors of space use. Fine-scale usage maps can be used in consenting and licensing of anthropogenic developments to determine local abundance. When quantifying commercial impacts through changes to species distributions, usage maps can be spatially explicitly linked to individual-based models to inform predicted movement and behaviour.

Biological and environmental effects on activity space of a common reef shark on an inshore reef

Proximity to land and sources of freshwater expose fishes residing on inshore reefs to fluctuating environmental conditions (e.g. high freshwater run-off/low salinity events). However, site attachment in many reef residents, such as reef sharks, could mean that relocation in response to unfavourable environmental conditions may not be feasible. Passive acoustic telemetry was used to monitor movement and space use of 18 blacktip reef sharks Carcharhinus melanopterus on an inshore reef off the coast of Queensland, Australia, to determine their response to environmental change. Activity space of sharks was modelled against combinations of environmental (wind speed, rain, salinity and water temperature) and biological (size, sex) factors. Size was the most influential predictor of space use, with larger sharks having larger activity spaces. Sex also appeared in top-performing models, showing that juvenile males use more space than juvenile females, although effects were marginal. Model results also indicated a relationship between shark activity space and salinity, where space use increased with decreasing salinity. A similar but weaker relationship was observed with water temperature. These results show that blacktip reef sharks respond to minor changes in salinity, suggesting that they may be able to relocate when conditions are unfavourable, and help define the resilience of this species to disturbance and change.

Off‐highway vehicle road networks and kit fox space use

ABSTRACTOff‐highway vehicle (OHV) use is popular for outdoor recreation across the United States, with especially high levels of participation in Arizona and the American Southwest. Road networks related to OHV recreation have the potential to influence kit fox (Vulpes macrotis) space use intensity. To evaluate the potential impacts of OHV road networks to kit fox space use, we conducted a study during 2010–2013 in 2 areas of the Sonoran Desert in central Arizona. We used an observational approach to determine the importance of road density to kit fox space use, relative to other measured environmental variables. We monitored 22 collared individuals and used linear mixed models and an information‐theoretic approach to develop models of intensity of space use for seasons of relatively low (e.g., 33% of yearly OHV use observed) and high (e.g., 67% of yearly OHV use observed) OHV use. We found road density to be the most important predictor of space use for kit foxes, relative to other measured environmental variables. Space use was negatively associated with road density during winter (Oct–Mar), which coincided with kit fox breeding, denning, and pupping activities and was the season of relatively higher OHV use. Road density in OHV use areas is an important seasonal predictor of, and can negatively influence, kit fox space use. OHV road networks may lead to effective habitat loss for kit foxes and managers must consider how OHV recreational opportunities should be balanced with habitat conservation for species like kit fox. © 2016 The Wildlife Society.

Space Use of Female Greater Prairie-Chickens in Response to Fire and Grazing Interactions

Ecological interactions between fire and grazing have shaped the evolutionary history of grassland ecosystems. Currently, grassland birds have experienced ongoing population declines, following widespread implementation of intensive rangeland management practices that reduce habitat heterogeneity. Patch-burn grazing is an alternative rangeland management strategy that promotes habitat heterogeneity and biodiversity. We conducted a 3-yr. field study in the central Flint Hills of Kansas to compare the spatial ecology of female Greater Prairie-Chickens (Tympanuchus cupido) in rangelands managed with intensive rangeland management versus patch-burn grazing. This is the first study on the effects of patch-burn grazing on the space use decisions of Greater Prairie-Chickens at the home range scale. We used seasonal estimates of home range for 6-mo breeding and nonbreeding periods, as well as resource utilization functions to investigate the response of female prairie chickens to landscape metrics describing fire, grazing, and proximity to anthropogenic structures or lek sites. In our analysis of all radio-marked females, distance to lek was consistently the strongest predictor of space use during both breeding and nonbreeding seasons. Females captured at properties managed with patch-burn grazing selected areas with low stocking rates and high fire frequencies, and they avoided recently burned areas. Our study provides new evidence that patch-burn grazing can improve grassland habitat for Greater Prairie-Chickens, an umbrella species in the tallgrass prairie ecosystem. Patch-burn grazing created preferred habitats for female Greater Prairie-Chickens, with a relatively frequent fire return interval, a mosaic of burned and unburned patches, and a reduced stocking rate in unburned areas avoided by grazers. Widespread implementation of patch-burn grazing could result in significant improvements in habitat quality for wildlife in the tallgrass prairie ecosystem.

Factors affecting female space use in ten populations of prairie chickens

Conservation of wildlife depends on an understanding of the interactions between animal movements and key landscape factors. Habitat requirements of wide‐ranging species often vary spatially, but quantitative assessment of variation among replicated studies at multiple sites is rare. We investigated patterns of space use for 10 populations of two closely related species of prairie grouse: Greater Prairie‐Chickens (Tympanuchus cupido) and Lesser Prairie‐Chickens (T. pallidicinctus). Prairie chickens require large, intact tracts of native grasslands, and are umbrella species for conservation of prairie ecosystems in North America. We used resource utilization functions to investigate space use by female prairie chickens during the 6‐month breeding season from March through August in relation to lek sites, habitat conditions, and anthropogenic development. Our analysis included data from 382 radio‐marked individuals across a major portion of the extant range. Our project is a unique opportunity to study comparative space use of prairie chickens, and we employed standardized methods that facilitated direct comparisons across an ecological gradient of study sites. Median home range size of females varied ~10‐fold across 10 sites (3.6–36.7 km2), and home ranges tended to be larger at sites with higher annual precipitation. Proximity to lek sites was a strong and consistent predictor of space use for female prairie chickens at all 10 sites. The relative importance of other predictors of space use varied among sites, indicating that generalized habitat management guidelines may not be appropriate for these two species. Prairie chickens actively selected for prairie habitats, even at sites where ~90% of the land cover within the study area was prairie. A majority of the females monitored in our study (>95%) had activity centers within 5 km of leks, suggesting that conservation efforts can be effectively concentrated near active lek sites. Our data on female space use suggest that lek surveys of male prairie chickens can indirectly assess habitat suitability for females during the breeding season. Lek monitoring and surveys for new leks provide information on population trends, but can also guide management actions aimed at improving nesting and brood‐rearing habitats.

Space use by female Greater Prairie‐Chickens in response to wind energy development

Wind energy development is targeted to meet 20% of U.S. energy demand by 2030. In Kansas, optimal sites for wind energy development often overlap with preferred habitats of Greater Prairie‐Chickens (Tympanuchus cupido), a lek‐mating species of prairie grouse with declining populations. Our goal was to use movement data from radio telemetry to investigate patterns and drivers of seasonal space use by female prairie‐chickens during pre‐ and post‐construction periods at a wind energy facility in northcentral Kansas. We developed individual and population level resource utilization functions (RUFs) for four time periods: the 6‐month breeding and nonbreeding seasons during the pre‐construction stage (2007–2008; n = 28 and 14 females), and the same two seasons during a post‐construction period (2009–2011; n = 102 and 37). RUFs relate non‐uniform space use within a home range to landscape metrics in a multiple regression framework. We selected ten predictor variables that described land cover, habitat patchiness, anthropogenic disturbance, and social behavior of prairie‐chickens. We documented two behavioral responses of females to wind energy development during the breeding season: (1) mean home range size increased approximately two‐fold, and (2) space use had a positive relationship with distance to turbine, which indicated female avoidance of wind turbines. A parallel study of demographic rates in our study population found no negative effects of wind energy development on prairie‐chicken fecundity or survival, but persistent avoidance of wind energy development could result in the local extirpation of prairie‐chicken populations at our study site. Our primary ecological finding was that distance to lek was the strongest predictor of space use during all treatment periods, with relatively high use of areas at short distances from leks in 79% of female home ranges. Thus, lek site surveys should be effective for identifying prairie grouse habitat preferences and monitoring population dynamics when more intensive demographic studies are not feasible. Our study is the first application of resource utilization function techniques to a wildlife population in response to energy development, and our results provide new quantitative insights into the spatial ecology of an upland gamebird of conservation concern.

Landscape structure influences space use by white-tailed deer

Variation in space-use patterns among free-ranging mammal populations has been an important area of study in behavioral ecology. We investigated the influence of landscape characteristics associated with landscape fragmentation and diversity on the home-range size of white-tailed deer (Odocoileus virginianus). We evaluated the relative contribution of 3 main land-cover types (forest, agriculture, and rangeland) to the composition of each home range and constructed sex- and season-specific linear regression models using landscape metrics relevant to habitat fragmentation and diversity. Both core and home-range areas were dominated by forest, agriculture, and rangeland. We found that landscape configuration metrics aimed at quantifying landscape fragmentation were good predictors of space use by white-tailed deer and that deer occupied smaller home ranges in highly fragmented areas. Our results indicate that once important cover types are present and patches are sized to meet the resource needs of the individual, configuration of those resource patches influences overall space use. These findings support the assertion that space use by white-tailed deer varies along a gradient of fragmentation.

Multi‐scale resource selection and spatial ecology of the Indian fox in a human‐dominated dry grassland ecosystem

Resource selection by animals is a scale-dependent hierarchical process of behavioural responses to environmental factors. Lack of information on such habitat selection dynamics can hamper the conservation management of species and habitats. For example, little is known about the space-use patterns of species in the semi-arid grasslands of peninsular India. The Indian fox Vulpes bengalensis, a poorly studied, yet reportedly widespread carnivore of the Indian subcontinent, represents an example of such lack of information. We determined the factors influencing habitat selection by Indian foxes at two levels in a multiple-use human-dominated landscape. Indian foxes are found in the highest densities in dry-grassland habitats, but are also reported to be opportunistic omnivores. Thus, we hypothesized that foxes select mainly for native grassland over human-modified habitats at a landscape level, but may not avoid human-modified habitats at the home-range level to take advantage of increased rodent availability in agricultural areas. We analysed radio-telemetry data from 32 Indian foxes using (1) a utilization distribution-weighted compositional analysis to determine the main components of home-range selection at the landscape level; (2) a discrete-choice analysis to determine the factors influencing the selection of habitat within the home ranges. At the landscape level, Indian foxes selected for native grasslands, forestry plantations and fallow land over human-dominated habitats such as agricultural land and human settlements. The presence of native grasslands was also the dominant predictor of habitat selection at the home-range scale across all seasons. Our results show that natural grasslands are the most important predictor of space use at multiple scales. This has important conservation implications as the threatened semi-arid short grasslands are poorly represented in India's protected area network. Although Indian foxes are not currently considered endangered, failure to conserve remaining native grassland habitats may threaten this species along with other grassland obligates.

Relationships Between Landscape Pattern and Space Use of Three Mammalian Carnivores in Central Mississippi

Space use and habitat selection have been studied extensively in mammalian carnivores, and it is widely accepted that many factors influence these parameters. Although landscape characteristics are perceived to be important in how carnivores use their environment, relatively few studies have evaluated influences of landscape features on carnivore behavior. We examined relationships between landscape pattern and space use in sympatric bobcats (Lynx rufus), coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) in central Mississippi during 1989–1997. We quantified landscape features within three different spatial scales (3000, 4500 and 6000 m) centered on home ranges of 46 bobcats, 12 coyotes and 22 gray foxes. We evaluated a suite of class- and landscape-level variables and their influence on space use of each species. Linear mixed models suggested that habitat interspersion (intermixing), patch shape (complexity) and edge contrast were important predictors of space use in bobcats. We failed to detect any relationships between landscape pattern and space use of coyotes and gray foxes. We offer that the relationships we observed are related to, and can be explained by, ecology and behavioral adaptations of each species.