Mean Home Range Size Research Articles

Spatial ecology and habitat use of giraffe (Giraffa camelopardalis) in South Africa

The lack of long-term studies remains a limiting factor in understanding the home range, spatial ecology and movement of giraffes. We equipped eight giraffes with GPS satellite units and VHF capacity, which were built in to the collars for the remote collection of data on their movements and home ranges over two years on Khamab Kalahari Nature Reserve (KKNR) within the Kalahari region of South Africa. Giraffe numbers in KKNR dropped from 135 individuals to 111 in just five years, revealing the lack of knowledge about their required habitat needs, space use and diet. With over 1000km2 available for roaming within the reserve, habitat selection, principle and preferred food species played a significant role in home range size and overlap between individuals. These giraffes used an average annual home range of 206km2 (20602ha) as calculated by a 95% minimum convex polygon (MCP) with a standard deviation core home range calculated by a 50% MCP of 10.1km2 to satisfy their annual needs for survival and reproduction in their preferred vegetation. In the wet, hot season (summer: December–February) when food was abundant, giraffes frequented smaller areas (average 177km2), while in the dry, cool season (winter: June to August) the mean home range size increased to approximately 245km2. Rainfall influenced spatial distribution since it determined vegetation productivity and leaf phenology. The different seasons influenced giraffe movements, while different vegetation types and season influenced their home range size. Season and food availability also influenced home range overlap between different giraffe herds. Home range overlap occurred when giraffes were forced to roam in overlapping areas during the dryer months when the winter deciduous nature of the majority of the tree species resulted in lower food availability. In winter, the overlap was approximately 31% and in autumn approximately 23%. During the wet and warmer months, overlapping was 15% in summer and 19% in spring, respectively. The percentage of time spent in different vegetation type areas was influenced by the abundance of the principal food species of that plant community. It is thus concluded that the movements of giraffes were primarily influenced by a combination of environmental factors such as season, rainfall and vegetation density.

Space invaders: effects of invasive alien Pallas’s squirrel on home range and body mass of native red squirrel

Alien species can affect native species through several ecological processes such as competition. Here we tested the hypothesis of interspecific competition for space and food resources between the native Eurasian red squirrel and the invasive Pallas’s squirrel introduced in Italy. We used an experimental study design comparing space and habitat use and body condition parameters of red squirrels between areas of co-occurrence with the Pallas’s squirrel and areas without it. There were no differences in mean home range size of red squirrels between red-only areas and red-Pallas. However, when Pallas’s squirrels were removed, the red squirrels increased their home ranges. Moreover, in the area of syntopy, red squirrels had a higher degree of intraspecific home range overlap than in the red-only area. We also found indirect evidence for competition for food with red squirrels having a poorer body condition when co-occurring with the alien species. We analyzed the body mass and size of red squirrels in the two areas and our results showed that red squirrels had a reduced body mass and size when in syntopy, confirming that the interspecific competition does not allow red squirrels to reach the optimum body condition that they would have if the competitor was not present. Moreover, tree-species niche overlap was very high and both species fed primarily on the same tree seeds. Differences in vegetation cover between areas are discussed. This is the first study that confirms the invasiveness of the Pallas’s squirrel also in terms of capability to compete with native species.

Seasonal home range dynamics and sex differences in habitat use in a threatened, coastal marsh bird.

A comprehensive understanding of spatiotemporal ecology is needed to develop conservation strategies for declining species. The king rail (Rallus elegans) is a secretive marsh bird whose range historically extended across the eastern United States. Inland migratory populations have been greatly reduced with most remaining populations inhabiting the coastal margins. Our objectives were to determine the migratory status of breeding king rails on the mid‐Atlantic coast and to characterize home range size, seasonal patterns of movement, and habitat use. Using radiotelemetry, we tracked individual king rails among seasons, and established that at least a segment of this breeding population is resident. Mean (±SE) home range size was 19.8 ± 5.0 ha (95% kernel density) or 2.5 ± 0.9 (50% kernel density). We detected seasonal variation and sex differences in home range size and habitat use. In the nonbreeding season, resident male home ranges coincided essentially with their breeding territories. Overwintering males were more likely than females to be found in natural emergent marsh with a greater area of open water. Females tended to have larger home ranges than males during the nonbreeding season. We report for the first time the use of wooded natural marsh by overwintering females. Brood‐rearing king rails led their young considerable distances away from their nests (average maximum distance: ~600 ± 200 m) and used both wooded natural and impounded marsh. King rails moved between natural marsh and managed impoundments during all life stages, but the proximity of these habitat types particularly benefitted brood‐rearing parents seeking foraging areas with shallower water in proximity to cover. Our results demonstrate the importance of interspersion of habitat types to support resident breeders. Summer draining of impounded wetlands that are seasonally flooded for wintering waterfowl allows regrowth of vegetation and provides additional habitat at a critical time for wading birds.

Ranges and Movements of Montezuma Quail in Southeast Arizona

Historical assumptions about Montezuma quail movements and home ranges at the population level are limited due to the lack of markrecapture studies on this species from which solid conclusions can be derived. Such information is crucial for estimating population sizes, densities, and rate of emigration and immigration throughout the landscape. Our study examined home range size of 29 Montezuma quail and movements of 65 quail in southeast Arizona from 2008–2010. We used radio telemetry to follow radio-tagged birds in 3 study sites that varied in vegetation composition and topography. Mean home range size (MCP) was about was similar (51 ha) to the largest use area (50 ha) described in the literature for this species. The largest MCP home range estimate (206.7 ha) was far larger than what has been reported in the literature. Within a season, the largest mean maximum distance moved between 2 locations was 1,128.4 ± 619.5 m and the largest maximum linear distance between 2 locations for an individual was 2,375.5 m. Results from our research should help to address knowledge gaps about Montezuma quail home ranges and movements and provide a baseline to assist management of this species in the future.

Habitat Selection of Northern Bobwhite Coveys on Two Intensive Agriculture Landscapes in Eastern North Carolina (Poster Abstract)

Little information is available for home range size and habitat use of northern bobwhites (Colinus virginianus) on modern agricultural landscapes in autumn. Therefore, we monitored radiomarked bobwhite coveys from September–December 1998 on farms in Wilson and Tyrrell counties, North Carolina. The Tyrrell County farm was a 6084-ha area recently developed for commercial production of corn and soybeans. Dispersed throughout crop areas were forested and fallow blocks at differing stages of succession. The Wilson County farms had small fields (x̄ = 1.8 ha, SE = 0.12) planted in cotton, soybeans, corn, and tobacco and were surrounded by mixed pine and hardwood blocks of differing ages. Mean home range size at the Tyrrell County farm was 33.2 ha (range 4.5–128.5 ha) (n = 10). The two largest home ranges, 70.7 and 128.6 ha, were disproportionately large due to large movements from harvested crop fields to permanent forested cover. Covey home ranges were not established at random (l = 0.124; x2 4= 20.18; P < 0.001). Road and canal edges were selected significantly more than any other habitat followed in rank by soybean fields, corn fields, forested, and fallow blocks. Road and canal edges provided necessary cover for moving between habitat types, especially from forested and fallow blocks to crop fields. Within home ranges, coveys did not allocate their time at random (l = 0.336; x2 4 = 10.89; P < 0.05). Habitats were ranked in the order of forested blocks, fallow areas, soybean fields, road and canal edges, and corn fields, but no significant differences were found between habitats. In Wilson County, average covey home range was 17.4 ha (Range: 4.9–37.6 ha)(n = 11). Coveys did not establish their home range at random (l = 0.407; x22 = 9.87; P < 0.05), selecting forested blocks over crop fields (T9 = 3.02, P < 0.012). Within home ranges coveys did not allocate their time at random (l = 0.1319; x25 = 22.28; P < 0.001), utilizing primarily forested blocks followed by cotton fields, soybean fields, corn fields, and other areas. On both study areas, forested and fallow blocks were the only source of cover to spend time in after crop harvest. Covey use within forested and fallow blocks was concentrated along edges of crop fields, leaving large portions of this habitat type unused. Forested and fallow blocks were primarily used as loafing cover in between feeding periods in adjacent crop fields.

Spring Dispersal of Northern Bobwhites in Southwestern Ohio

Northern bobwhites (Colinus virginianus) historically occurred throughout Ohio but their core range has contracted to 18 southwestern counties. The Ohio Division of Wildlife has used trapping and transplanting to reintroduce wild bobwhites to unoccupied habitats within the species’ historic range. Bobwhite dispersal information is necessary to understand population dynamics and the species’ capacity to recolonize unoccupied habitats. Bobwhites were captured and radiomarked on 4 private-land study sites in southwestern Ohio. Radio-marked bobwhites (n 1⁄4 66) were tracked by homing or triangulation during spring 2010 and 2011 to ascertain dispersal distances between winter and breeding ranges. The spring dispersal period was defined by break-up of coveys and subsequent occupation of breeding season home ranges. The dispersal period, defined by non-affiliation with coveys, long directional daily movements, and observed breeding activity, varied among individuals and ranged from 2 April to 26 May. Dispersal distances were measured as the net Euclidean distance between locations recorded at the beginning and end of the dispersal period. Dispersers were defined as birds that moved . 23 the diameter of the mean home-range size (26.1 ha) observed during October-March 2010 and 2011. Movements of 1–2 home-range diameters were classified as home range shifts. Non-dispersing bobwhites traveled , 1 home-range diameter. Mean movement for all birds was 1.54 km. Twenty-eight (42.4%) radio-marked bobwhites were non-dispersers, 15 (22.7%) shifted home ranges, and 23 (34.8%) dispersed. Non-dispersers moved a mean of 0.31 km (range 1⁄4 0.03–0.56 km), home range shifts averaged 0.78 km (range 1⁄4 0.60–0.99 km), and dispersers traveled a mean distance of 3.6 km (range 1⁄4 1.18–11.5 km). Dispersal distance was lowest for adult females and increased in order for adult males, juvenile females, and juvenile males. Dispersal distance decreased as the proportion of early successional wooded habitat within winter home ranges increased. Sex, age, and dispersal distance did not affect survival. Our results suggest Ohio bobwhites are capable of expanding their range into historically-populated areas.

Resilience to agricultural habitat fragmentation in an arboreal marsupial

The impact of habitat fragmentation on arboreal mammals is poorly understood and potentially greater than for ground-dwelling mammals. We investigated the influence of landscape fragmentation on a generalist arboreal marsupial, the koomal (Trichosurus vulpecula hypoleucus), a geographically isolated subspecies of the common brushtail possum endemic to south-western Australia. Since European settlement this taxon has undergone a significant reduction in range and population. We describe a year-long trapping study, incorporating radio-tracking, of a koomal population in a fragmented agricultural landscape to determine how agriculture and habitat fragmentation affect populations. In all, 61 free-ranging individuals were captured. Mark–recapture modelling estimated the population of 28.8 per trapping event with a total population size of 69 individuals having been present in the test landscape during the course of the study. Population demographics were comparable with populations found in relatively continuous landscapes. Mean home-range size was 8.8 ha of remnant vegetation for males and 7.9 ha for females. Home ranges usually incorporated several patches. Utilisation of shrublands, wetlands, and areas infested with Phytophthora dieback was not observed. Individuals required access to a selection of suitable denning trees and distances between patches &lt;100 m did not appear to impair movement, with gaps &lt;400 m regularly crossed.

Land sharing is essential for snow leopard conservation

Conserving large carnivores in an increasingly crowded planet raises difficult challenges. A recurring debate is whether large carnivores can be conserved in human used landscapes (land sharing) or whether they require specially designated areas (land sparing). Here we show that 40% of the 170 protected areas in the global range of the snow leopard (Panthera uncia) are smaller than the home range of a single adult male and only 4–13% are large enough for a 90% probability of containing 15 or more adult females. We used data from 16 snow leopards equipped with GPS collars in the Tost Mountains of South Gobi, Mongolia, to calculate home range size and overlap using three different estimators: minimum convex polygons (MCP), kernel utility distributions (Kernel), and local convex hulls (LoCoH). Local convex hull home ranges were smaller and included lower proportions of unused habitats compared to home ranges based on minimum convex polygons and Kernels. Intra-sexual home range overlap was low, especially for adult males, suggesting that snow leopards are territorial. Mean home range size based on the LoCoH estimates was 207km2±63 SD for adult males and 124km2±41 SD for adult females. Our estimates were 6–44 times larger than earlier estimates based on VHF technology when comparing similar estimators, i.e. MCP. Our study illustrates that protected areas alone will not be able to conserve predators with large home ranges and conservationists and managers should not restrict their efforts to land sparing.

Dingoes at the Doorstep: Home Range Sizes and Activity Patterns of Dingoes and Other Wild Dogs around Urban Areas of North-Eastern Australia.

Simple summaryConflicts with dingoes and other wild dogs are becoming increasingly common in and around urban areas of Australia. A lack of basic information about wild dog movement ecology hampers efficient planning and allocation of resources to mitigate human–wild dog conflicts. We captured, collared and released 37 wild dogs in urban areas of north-eastern Australia to investigate their movement ecology. In general, wild dogs occupied small fragments of bushland within an urban matrix, were active at all times of the day, and lived within a few hundred meters of houses and humans at all times. We conclude that wild dog management strategies in urban areas should focus on the mitigation of impacts at the individual or group level, and not population-level reductions in numbers.Top-predators around the world are becoming increasingly intertwined with humans, sometimes causing conflict and increasing safety risks in urban areas. In Australia, dingoes and dingo × domestic dog hybrids are common in many urban areas, and pose a variety of human health and safety risks. However, data on urban dingo ecology is scant. We GPS-collared 37 dingoes in north-eastern Australia and continuously monitored them each 30 min for 11–394 days. Most dingoes were nocturnal, with an overall mean home range size of 17.47 km2. Overall mean daily distance travelled was 6.86 km/day. At all times dingoes were within 1000 m of houses and buildings. Home ranges appeared to be constrained to patches of suitable vegetation fragments within and around human habitation. These data can be used to reallocate dingo management effort towards mitigating actual conflicts between humans and dingoes in urban areas.

Space use and social ecology of coyotes (Canis latrans) in a high-elevation ecosystem: relative stability in a changing environment

Coyote (Canis latrans) spatial and social ecology are variable, but have been little studied in high-elevation environments. In these temperate ecosystems, large ungulates are prevalent and coyote pack size may be large in order for them to scavenge and defend ungulate carcasses from conspecifics in neighboring packs. We initiated a study to understand the spatial and social ecology of coyotes on the Valles Caldera National Preserve, a high-elevation (2450–3400 m) protected area in northern New Mexico. Our objectives were to (1) describe the home range size and habitat use of coyotes in the preserve, (2) describe coyote movements within and outside of packs, and (3) to evaluate the relationship between coyote social cohesion and the amount of elk (Cervus elaphus) in the coyote diet. We acquired global positioning system and telemetry locations from 33 coyotes from August 2005 to July 2009. We classified 23 coyotes (70 % of individuals) as residents (i.e., territorial) during at least part of the study and ten coyotes (30 %) as transients. Overall mean home range size of resident packs was 10.6 ± 2.2 (SD) km2. Home range size varied between packs, but did not vary by season or year. Coyotes used dry and wet meadow habitats as expected based on availability; coyotes used riparian habitat more than expected, and forests less than expected. Social cohesion did not vary among biological seasons. Alpha coyotes were more socially cohesive with each other than with other pack members, and a transient exhibited temporal–spatial avoidance of pack members while inside the pack’s territory followed by integration into the pack. Contrary to expectations, we found no relationship between coyote social cohesion and the proportion of elk in coyote diets. We concluded that coyote space use and sociality on the preserve were relatively stable year-round despite changes in biological needs, snow depth, and utilization of variously sized prey.

The short-term impact of abundant fruit upon deer mouse (Peromyscus maniculatus), southern red-backed vole (Myodes gapperi), and woodland jumping mouse (Napaeozapus insignis) populations

Fruit has been identified as an important and potentially population-restricting food for southern red-backed voles (Myodes gapperi (Vigors, 1830)), deer mice (Peromyscus maniculatus (Wagner, 1845)), and woodland jumping mice (Napaeozapus insignis (Miller, 1891)). We added domestic dried strawberries (Fragaria × ananassa (Weston) Duchesne ex Rozier (pro sp.)) and European black currants (Ribes nigrum L.), which have native analogues and are preferred foods of these rodents, to white spruce (Picea glauca (Moench) Voss) plantations from May through August 2011 and 2012 to test fruit and fruit-based carbohydrate’s short-term (1–2 years) impact on these rodent populations. We used mark–recapture to estimate density, percentages of population that were juvenile and breeding female, mean home-range size, and body mass during spring and summer of both years, and fecundity via placental scars from euthanized females in summer 2012. Fruit enhancement had no apparent effect on our species’ fecundity, proportion of breeding females or juveniles during spring and summer of either year, nor were there differences among these metrics in spring 2012 following 2011 fruit additions. Overall, there were no impacts to the short-term adult population dynamics for any species during fruit addition. We are led to believe that short-term pulses of fruit and (or) fruit-based carbohydrate abundance do little to influence temperate forest small-mammal populations.

Short-term responses of Timber Rattlesnakes (Crotalus horridus) to even-aged timber harvests in Indiana

The Timber Rattlesnake (Crotalus horridus) is a species of conservation concern throughout much of the Midwestern United States. While the habitat preferences of Timber Rattlesnakes have been studied throughout much of its range, little empirical data is available on the effects of forest management on this species. During 2007–11, we monitored movements of 47 adult Timber Rattlesnakes using radio telemetry in southcentral Indiana. Snakes were tracked during one or more seasons (April-October) for two years prior to, and three years following scheduled timber harvests (4-ha clearcuts and 4-ha understory removal as the first stage of shelterwood harvests). Annual home range estimates (100% Minimum Convex Polygon [MCP]) for both sexes combined ranged from 1.6ha to 271.3ha. The average home range for males (68.8ha) was larger than for either non-gravid females (22.7ha) or gravid females (11.7ha). Mean home range size using MCPs or kernel density estimates did not change from pre- to post-harvest in control sites or even-aged sites for either sex. The daily distance traveled by snakes and their proportional use of areas within harvest boundaries did not differ between treatment periods. Canopy and understory removal on a small scale (approx. 4ha) in a forested landscape did not affect seasonal or fine-scale movements of adult Timber Rattlesnakes 1–3years post-harvest. Our results suggest that this scale of timber harvesting is compatible with Timber Rattlesnakes.

Home Range of Noack's Round-Leaf Bat (Hipposiderosaff.ruber) in an Agricultural Landscape of Central Ghana

Thirteen individuals of Noack's round-leaf bat, Hipposideros aff. ruber, were radio-tracked for 38 nights in an agricultural landscape in Kwamang, Ashanti Region, Ghana. Local convex hulls were used to estimate home range sizes of the bats. Based on 1,192 fixes, the mean (± SD) home range size was 36 ha ± 35 ha. Individual home range size ranged from six to 95 ha and frequently overlapped among individuals. The foraging area covered 50% of the home range while the core area formed 2%. The mean maximum foraging distance was 1.1 km, with individual distances up to 2.6 km, suggesting Hipposideros aff. ruber is capable of covering relatively long distances. Male bats returned to the cave more often than females during the night. Although the cave was the main roost, each bat also had individual night roosts on trees.

Spatial ecology of coyotes in the Denver metropolitan area: influence of the urban matrix

Urbanization alters landscapes and ecosystem processes that result in negative impacts for many species. However, urbanization also creates novel environments that certain species, including carnivores, are able to exploit. Coyotes ( Canis latrans ) are 1 example of a species capable of exploiting urban environments throughout North America and, in some cases, becoming involved in human–coyote conflict. As part of a comprehensive study of human–coyote coexistence in the Denver metropolitan area of Colorado, we investigated the spatial ecology of coyotes to determine movement and activity patterns relative to the urban matrix. We examined home-range size, habitat use, and resource selection for 22 coyotes monitored with GPS collars during 2012–2014. Mean (± SD ) home-range size of resident coyotes (11.6±11.0 km2) was smaller than ranges of transient coyotes (200.7±232.4 km2). Home-range size did not vary by season or sex, but resident coyotes during the day (7.2±10.5 km2) had smaller home ranges than during the night (11.3±10.8 km2). Coyotes had high percentages of developed lands (44.5±18.9%) within their home ranges, contrary to previous studies of urban coyotes. However, the percentage of coyote locations in natural lands (48.9±22.4%) was higher than in developed lands (20.6±11.7%). Home-range size of residents was not related to either the percentage of developed lands or altered lands within home ranges. Coyotes selected natural lands over developed lands, and they increased activity at night. Although coyotes were able to thrive in home ranges containing large amounts of development, they continued to avoid areas with high human activity by primarily residing in areas with natural land cover. Similar to urban areas throughout the Northern Hemisphere, coyotes in the Denver metropolitan area have become efficiently adapted to a highly developed landscape, reflecting the flexible nature of this opportunistic carnivore.

Home range of reintroduced Chinese water deer in Nanhui East Shoal Wildlife Sanctuary of Shanghai, China

The Chinese water deer was once widely spread in Liaodong Peninsula, North China Plain and both banks of the Yangtze River and the Korean peninsula. Due to long-term environmental changes and influence of human development, its wild population in China has rapidly declined, both in abundance and distribution. As one of the native species in the history of Shanghai, Chinese water deer was introduced to Shanghai for captive breeding in 2006 and were released into the wild in 2010. The present study was conducted in Nanhui East Shoal Wildlife Sanctuary. The reintroduction of Chinese water deer was carried out separately in June and October 2010. So as to study the movement of the deer after release, 12 Chinese water deer (sex ratio 1 : 1) were tagged with radio-collars. We successfully used radio-telemetry to track 10 deer, and used the minimum convex polygon (MCP) and fixed kernel estimation (FKE) methods to calculate their home range. The results showed that using the MCP method, the mean home-range size of Chinese water deer was estimated to be 671 ha (range 245–1559 ha), while using the 95% FKE method, the mean was estimated to be 262 ha (range 43–435 ha). The mean home-range size of a buck was smaller than that of a doe by both MCP and FKE. The mean home-range size of an adult female was smaller than that of a subadult female. The largest seasonal home-range size (MCP, 275 ha) occurred during the winter of the first year, which then kept on shrinking in spring and summer. Home-range overlap was found among the home range of each individual. The mean overlap size was 303 ha. The mean overlap size was 135 ha in bucks, 422 ha in does and 270 ha between the buck and the doe. The study reflects that the seasonal food change is probably the main factor for the change of home-range size. Oestrus may also result in the enlargement of home range in winter. As an attempt to reintroduce large mammals to cities, we hope to provide useful experience for future wildlife management and conservation.

Home-Range and Foraging Areas of the Dawn BatEonycteris spelaeain Agricultural Areas of Thailand

We studied the foraging behaviour of the dawn bat Eonycteris spelaea, a cave roosting nectarivore widespread in SE Asia, and principal pollinator of economically important crops. We radio-tracked 17 individuals for five to 19 nights over a three month period. The bats were from three cave colonies in agricultural habitats in southern Thailand. They traveled between one and 17.9 km ( ± SD: 4.4 km ± 5.07, median = 2.34) from their roosting cave to food sources. The mean home-range size of the individuals varied with the method used in its calculation from 518.4 ha (100% Minimum Convex Polygon, MCP) to 564.5 ha (100% Local Convex Hull method, LoCoH) and 460.8 ha (95% Kernel density estimation, KDE). The mean size of foraging areas used by the bats also varied according to the method of calculation from 14.26 ha (100% MCP), 13.25 ha (100% LoCoH) and 38.52 ha (95% KDE) and accounted for 21.9%, 20.08% and 40.5% of the respective home-range size. The bats foraged in one to three foraging areas each night. The gr...

Home range and habitat use of juvenile green turtles (Chelonia mydas) in the northern Gulf of Mexico

For imperiled marine turtles, use of satellite telemetry has proven to be an effective method in determining long distance movements. However, the large size of the tag, relatively high cost and low spatial resolution of this method make it more difficult to examine fine-scale movements of individuals, particularly at foraging grounds where animals are frequently submerged. Acoustic telemetry offers a more suitable method of assessing fine-scale movement patterns with a smaller tag that provides more precise locations. We used acoustic telemetry to define home ranges and describe habitat use of juvenile green turtles at a temperate foraging ground in the northern Gulf of Mexico. We outfitted eight juvenile green turtles with acoustic transmitters and tracked them from 14 to 138 days from September 2012 to February 2013 in St. Joseph Bay, Northwest Florida. Mean home range size was relatively small compared to other studies. For four turtles, we observed a moderate inverse relationship between water temperature and water depth which is consistent with the idea that turtles moved to deeper waters when temperatures cooled. On average distance to the channel from turtle locations were different by bottom cover type. These turtles appear to forage in shallow-water seagrass beds that border deep channels. When water temperatures dropped in winter, some of the tracked turtles moved to a deep-water channel on the western side of the study site. Turtles whose foraging sites were farther from the deep-water channel exhibited greater displacement than those with sites that were closer to the channel. Green turtles in St. Joseph Bay have relatively small home ranges and many contain multiple activity centers. The frequent use of channels by turtles suggests bathymetry plays a major role in habitat selection of juvenile green turtles, particularly as temperatures drop in winter. The quality and density of seagrass habitat in St. Joseph Bay and its proximity to deep channels appears to provide ideal conditions for juvenile greens. The results of this study help define characteristics of foraging habitat utilized by juvenile greens in the northern Gulf of Mexico that managers can use in creating protected areas such as aquatic preserves.

Hierarchical habitat selection by Eurasian Pygmy Owls Glaucidium passerinum in old-growth forests of the southern French Prealps

Maintaining or restoring old-growth stand structures in mountain forests, including deadwood and snags provided by natural disturbances, is considered critical for the conservation of secondary cavity-nesting birds. Under current climate warming, old-growth mountain forests might become increasingly important for boreo-alpine species living in the southern part of their ranges. Here, we focused on hierarchical habitat selection by Eurasian Pygmy Owls Glaucidium passerinum in mixed mountain forests at their low latitude range limit in the southern French Prealps. We quantified Pygmy Owl habitat use at complementary hierarchical levels, from the local population to individual home ranges, by combining systematic playback counts and radio-telemetry. Mean home range sizes for breeding adult males covered 0.67 km2, ranging between 0.46 and 0.98 km2. We found evidence for Pygmy Owl habitat selection being a consistently hierarchical process, with (1) fir-dominated forests selected as the main habitat at the population level; (2) old-growth fir-dominated forest stands including edges with grassland gaps and karstic eroded areas selected at the home range level; and (3) amount of surrounding dead or decaying spruces increasing the occurrence probability of owl nesting cavities. Conserving Pygmy Owls at their low latitude range limit therefore requires the maintenance of old-growth mixed forests dominated by firs that provide these critical habitat features within a complex and heterogeneous landscape mosaic.

An artificial waterway and road restrict movements and alter home ranges of endangered arboreal marsupial

Artificial linear structures can cause habitat fragmentation by restricting movements of animals and altering home ranges. The negative impacts of these linear structures, especially of those other than roads, on arboreal species have been rarely studied even though these species can be greatly affected because of their fidelity to the canopy. We studied the home ranges of an endangered arboreal marsupial, the western ringtail possum (Pseudocheirus occidentalis), with a focus on the impacts of a road and an artificial waterway on their movement. We radiotracked 18 females and 19 males along a major road and an artificial waterway near Busselton, Western Australia, for 3 years and estimated home ranges using an a-local convex hull (a-LoCoH) estimator. No possum crossed the road successfully during the monitoring period while one crossed the waterway. Males had a mean home range size of 0.31 ± 0.044 (SE) ha, almost double that of the females at 0.16 ± 0.017 ha. Possums near the waterway had larger home ranges (0.30 ± 0.048 ha) than those near the road (0.19 ± 0.027 ha), and the size increased with proximity to the waterway, probably due to the greater availability of nearby canopy connections and the lower availability of preferable foliage. These results demonstrate that both the road and waterway represent significant physical barriers to possums, and the artificial waterway influenced home ranges more severely than the road. This suggests that linear infrastructure other than roads can affect movements of strictly arboreal animals, and negative impacts of these structures need to be assessed and mitigated by reconnecting their habitat, just as those of roads.

Population size and spatial ecology of Blanding’s Turtle (Emydoidea blandingii) in South March Highlands, Ottawa, Ontario, Canada

Between 2010 and 2011, an arterial road was constructed within provincially significant wetlands in the South March Highlands (SMH) located in Ottawa, Ontario, Canada. The wetlands and adjacent upland areas were determined to be sensitive habitat for Blanding’s Turtles (Emydoidea blandingii (Holbrook, 1838)) during the approval and permitting process, and a population study was required as part of the road construction project. The study consisted of a 4-year mark–recapture program and a movement study of radio-tagged adult turtles. General findings included the identification of 27 adult males and 55 females and a population estimate of 93 adults (95% Cl: 86–118). A 1:2.32 male to female sex bias was also found. Mean home-range size was 19.06 ha and tagged turtles moved, on average, more per observation in 2013 (191.40 m compared with 89.75 and 123.04 m in 2011 and 2012, respectively). Previously reported differences in movement patterns between males, females, and gravid females were not observed. The SMH Blanding’s Turtle population should be closely monitored because urban development continues in the area, which may further reduce the population size. Understanding the biology of imperiled populations across species’ ranges is necessary to promote conservation and adaptive wildlife management.