Bulk feeder or selective grazer: African buffalo space use patterns based on fine-scale remotely sensed data on forage quality and quantity

An individual’s spatial behavior is shaped by social and environmental factors and provides critical information about population processes to inform conservation and management actions. Heterogeneity in spatial overlap among conspecifics can be evaluated using estimates of home ranges and core areas and used to understand factors influencing space use and territoriality. To understand and test predictions about spatial behavior in an invasive large mammal, the wild pig (Sus scrofa), we examined variation in space use between sexes and seasons. We predicted that if animals were territorial that there would be a reduction in space-use overlap when comparing overlap of home ranges (HR–HR), to home ranges and core areas (HR–CA), and in-turn between core areas (CA–CA). Home ranges and core areas were estimated for 54 wild pigs at Buck Island Ranch, FL from GPS telemetry data. Overlap indices were calculated to estimate the strength (space-use overlap) and number of potential interactions within three wet seasons (June–October) and two dry seasons (December–April). Among sexes, home range size did not vary seasonally, and males exhibited larger home ranges compared to females (M = 10.36 ± 0.79 km2 (± SE), F = 3.21 ± 0.16 km2). Strength of overlap varied by season with wild pig home ranges overlapping more during the dry season. Males interacted with a greater number of individuals of both sexes, compared to females, and exhibited greater strength of overlap during the dry season. Consistent with our predictions, wild pigs appeared to exhibit territorial behavior, where strength of overlap decreased when comparing HR–HR to HR–CA and HR–CA to CA–CA. Our framework can be used to understand patterns of space use and territoriality in populations, which has important implications in understanding intraspecific interactions and population processes, such as how pathogens and parasites might spread within and among populations.

In wildlife research, telemetry data are often converted to home ranges. The concept of an animal’s home range can be defined as the “. . . area traversed by the individual in its normal activities of food gathering, mating and caring for young” (Burt, 1943, pg. 351). The delineation and analysis of home ranges is common in wildlife research, and several reviews of home range studies exist (Harris et al., 1990; Laver & Kelly, 2008). Site fidelity (Edwards et al., 2009), population abundance (Trewhella et al., 1988), prey-predatory abundance (Village, 1982), impacts of human disturbance (Apps et al., 2004; Berland et al., 2008; Frair et al., 2008; Rushton et al., 2000; Thiel et al., 2008), feeding strategies (Hulbert et al., 1996) and ecological correlates of critical habitat (Tufto, 1996; Fisher, 2000) are examples of topics addressed using home range as the analysis unit. Home ranges are typically delineated with polygons. Locations within the polygon are considered part of the animal’s home range, and locations outside are not. As evidenced by the large number of home range studies, such binary approaches have been useful. However, landscape use by wildlife is spatially heterogeneous (Johnson et al., 1992; Kie et al., 2002). Edges (Yahner, 1988), disturbances (i.e., roads and forest harvesting) (Berland et al., 2008), and patch size (Kie et al., 2002) are just a few landscape features that cause heterogeneity in the geographic distribution of wildlife within home ranges. To account for spatial heterogeneity within a home range, core areas, defined as those used most frequently and likely to contain homesites, along with areas of refuge and dependable food sources (Burt, 1943) are sometimes delineated to create categories of habitat use (e.g., Samuel et al., 1985). Characterizing the spatial variation in wildlife distributions should improve our understanding of habitat use, especially in conjunction with the growing spatial extents of wildlife data sets. Arguably, the two most common approaches to demarcating a home range are the minimum convex polygon and kernel density estimation (Harris et al., 1990). The minimum convex polygon tends to overestimate home range size by including all the unused areas between outermost locations and increasing in area with large sample sizes (Borger et al., 2006a; Katajisto & Moilanen, 2006). As such, kernel density estimation is often preferred when demarcating a home range (Seaman & Powell, 1996; Marzluff et al., 2004; Borger et al., 2006a; Laver & Kelly, 2008). Although used to delineate binary home ranges, kernel density estimation generates a surface of values within the home range, which is useful for characterizing spatial variability in wildlife intensity. Kernel density surfaces are often referred to as utilization distributions as they give values that indicate higher and lower utilization of locations by individuals.

Context Home range studies allow investigation of faunal habitat use within a well-defined area, and for some species, the concept of ‘core’ and ‘non-core’ home ranges provides the means to examine how resource use varies within home ranges. Taking this approach, we investigated whether koalas preferentially used areas of taller forest canopy within home ranges. After an extensive examination of data quality and home range estimation methods, we used remote sensing techniques to provide canopy height information at high resolution. Aims In many areas, koalas prefer taller individual trees at the plot scale; our aim was to investigate whether koalas prefer forest areas with higher canopy height within their home ranges. Methods In our southeast Queensland study area, we developed a canopy height model (CHM) from airborne LiDAR (Light Detection and Ranging) data. Existing radio telemetry and GPS data from 135 koalas were used to generate home ranges using 95% kernel density estimators, and 50% kernels represented core home ranges. Some home ranges occupied more than one forest type (Regional Ecosystem – RE); we treated each RE as an individual patch, and used 225 patches in our analysis. We intersected the 95% kernels with the CHM, and used hierarchical spatial clustering to derive four categorical canopy height classes within each patch. We then compared differences in height class area proportions between core and non-core areas for each patch. Key results The highest of the four canopy height classes comprised a significantly higher proportion of core areas (42.3%) than non-core areas (30.7%). Classes 2 and 3 were evenly distributed, and the proportion of Class 4 (lowest canopy height) was 20.3% of non-core areas and 11.0% in core areas. Results were similar for REs grouped by Land Zone and individual REs. Conclusions and implications We conclude that areas of higher canopy are an important habitat resource for koalas. We have, for the first time, examined resource variability within entire koala home ranges using remote sensing, and our methods demonstrate an avenue for further research using other forms of remote sensing. Classified canopy height models could also be used for strategic conservation planning, and at population-level koala habitat management when combined with other relevant habitat factors.

Knowing the home range of a species helps to identify the resources it needs to survive and reproduce and how this behavior is expressed spatially. Within home ranges, core areas are the sites where the main resources are abundant. The microhabitat is a spatial area composed of variables that can affect individual behavior. In this sense, the characterization of this inner part of the home range can contribute significantly to understanding the elements that these areas offer compared to the rest of the habitat of a population. This work characterized the home range and areas outside it, as well as the core areas of female mule deer on a microhabitat scale in the Chihuahuan Desert, México. The structure and composition of the vegetation were characterized according to three habitat use hierarchies: interior of the core areas and zones within and outside the home ranges of seven female mule deer. A Principal Component Analysis (PCA) was performed, and a hierarchical clustering was used to relate the variables. The variation in structure and composition in each hierarchy was evaluated by performing multivariate permutation tests. Twenty-five plant species were recorded in the transects. The PCA showed the most similar use hierarchies are the core and home range inner areas. The core area presents higher density and cover-dominance values, and the zone outside the home range showed high values of distance to the individual closest to the central point and greater variation in this parameter. The MANOVA indicated a significant variation in vegetation structure and composition in relation to use hierarchies. Significant differences in vegetation structure and composition were found at the microhabitat level between the core area of activity and the zones within and outside the home range. The core area has a greater structural complexity of vegetation, with greater plant coverage-abundance and density; this suggests that the core area is located in a more competitive and saturated environment. Outside the home range, the microhabitat has greater spatial heterogeneity of vegetation, with greater distance and variation of plant cover. Future research could address the spatial (micro-macro) and temporal scales to better understand the ecological dynamics of the species in different habitat use hierarchies.

Adaptive behavioural strategies to seasonal challenges by a semiurban feral ungulate

White-tailed deer are the most important game species in Louisiana, and throughout the southeastern United States. Likewise, the forest products industry represents the most important agricultural commodity in Louisiana, and industrial landowners frequently lease their properties to sportsmen specifically for white-tailed deer hunting. I conducted research assessing survival, space use, and habitat selection of white-tailed deer on a 3885 ha industrial forest owned by Plum Creek Timber Company. I captured 61 deer in Union Parish, Louisiana in 2009-2010, radio-marked 24 females and 23 males, and ear-tagged 7 females and 6 males. Season and sex interacted to affect home range and core area sizes. Males home range sizes varied seasonally and were 232 ha, 70 ha, and 129 ha for spring, summer, and fall respectively. Female home range sizes did not differ seasonally and were 104 ha, 90 ha, and 62 ha for spring, summer, and fall respectively. Forest openings were important to both sexes when establishing home ranges. Core area selection exhibited a season and sex interaction as both sexes shifted selection in the fall to 0-4 year old pine and 13-19 year old pine stands. Use of habitats within home ranges did not vary by sex, season, or an interaction between them. Males and females chose 5-12 year old pine stands consistently across all seasons. Survival differed by season, but not by sex. Survival rates for adult males in spring, summer, and fall were 0.95, 0.97, and 0.54 respectively. Survival rates for females were 0.95, 0.97, and 0.56 for spring, summer, and fall respectively. All fall mortality was hunting-related, whereas mortalities during spring and summer resulted from unknown causes. The extensive use of bait, primarily corn and rice bran, was thought to influence space use and survival, and further research is needed to determine the effects of baiting on susceptibility of harvest of different age classes and sexes.

BackgroundAssessing wildlife movements and habitat use is important for species conservation and management and can be informative for understanding population dynamics. The African buffalo (Syncerus caffer) population of Ruaha National Park, Tanzania has been declining, and little was known about the movement, habitat selection, and space use of the population, which is important for understanding possible reasons behind the decline. A total of 12 African buffalo cows from four different herds were collared with satellite transmitters. Movements were assessed over 2 years from 11 animals.ResultsThe space use of the individual collared buffaloes as an approximation of the 95% home range size estimated using Brownian bridge models, ranged from 73 to 601 km2. The estimated home ranges were larger in the wet season than in the dry season. With the exception of one buffalo all collared animals completed a wet season migration of varying distances. A consistent pattern of seasonal movement was observed with one herd, whereas the other herds did not behave the same way in the two wet seasons that they were tracked. Herd splitting and herd switching occurred on multiple occasions. Buffaloes strongly associated with habitats near the Great Ruaha River in the dry season and had little association to permanent water sources in the wet season. Daily movements averaged 4.6 km (standard deviation, SD = 2.6 km), with the longest distances traveled during November (mean 6.9 km, SD = 3.6 km) at the end of the dry season and beginning of the wet season. The shortest daily distances traveled occurred in the wet season in April–June (mean 3.6 km, SD = 1.6–1.8 km).ConclusionThe Great Ruaha River has experienced significant drying in the last decades due to water diversions upstream, which likely has reduced the suitable range for buffaloes. The loss of dry season habitat due to water scarcity has likely contributed to the population decline of the Ruaha buffaloes.

Nelson's (Ammodramus nelsoni) and Saltmarsh (A. caudacutus) sparrows are sympatric breeders in tidal marshes of the southern Gulf of Maine. These sparrows hybridize, have different mating strategies, and males do not defend territories or provide parental care. We estimated and compared core area sizes, home range sizes, and habitat use between species and between males and females. We radio-marked 140 sparrows (63 Nelson's and 77 Saltmarsh sparrows) during three breeding seasons (1999–2001) at Scarborough Marsh, Maine, USA. Home ranges of male A. nelsoni were 2.3 times larger (± SE) (119.68 ± 19.43 ha) than those of male A. caudacutus (52.85 ± 8.68 ha). Home range sizes of female Nelson's and female Saltmarsh sparrows did not differ from each other (female Nelson's home range = 43.58 ± 13.10 ha; female Saltmarsh home range = 27.81 ± 6.3 ha). More than 40% of male and 18% of female home ranges had two discrete core areas and, in most instances, each core area corresponded to a separate lunar cycle. We suggest that differences in mating strategies, densities, and adaptation to nesting in tidal marshes explain the larger home range estimates for male Nelson's Sparrows. Female and male Nelson's Sparrows' home ranges had more Spartina alterniflora cover and female Saltmarsh Sparrows' home ranges had greater Juncus gerardii cover than random locations. Home ranges of female Saltmarsh Sparrows had less Spartina alterniflora cover and more Juncus gerardii cover than female Nelson's Sparrows. We did not detect any differences in vegetation variables between male Saltmarsh and male Nelson's sparrow home ranges.

Feral cats (Felis catus) are one of the world’s worst invasive species with continuing expanding populations, particularly in urban areas. Effects of anthropogenic changing land-use, especially urbanisation, can alter distribution and behaviour of feral cats. Additionally, resource availability can influence home range and habitat use. Therefore, we investigated home range and habitat use of feral cats (n = 11) in an urban mosaic with varying degrees of urbanisation and green spaces in Pietermaritzburg, KwaZulu-Natal, South Africa. Using global positioning cellular trackers, individual feral cats were followed for a minimum of six months. Minimum convex polygons (MCP) and kernel density estimates (KDE) were used to determine their home range, core area size, and habitat use. Mean home range (± SE) for feral cats was relatively small (95% MCP 6.2 ± 4.52 ha) with no significant difference between male and female home ranges, nor core areas. There was individual variation in home ranges despite supplemental feeding in the urban mosaic. Generally supplemental resources were the primary driver of feral cat home ranges where these feeding sites were within the core areas of individuals. However, the ecological consequences of feeding feral cats can increase their survival, and reduce their home ranges and movement as found in other studies.

The population density of wildlife reservoirs contributes to disease transmission risk for domestic animals. The objective of this study was to model the African buffalo distribution of the Kruger National Park. A secondary objective was to collect field data to evaluate models and determine environmental predictors of buffalo detection. Spatial distribution models were created using buffalo census information and archived data from previous research. Field data were collected during the dry (August 2012) and wet (January 2013) seasons using a random walk design. The fit of the prediction models were assessed descriptively and formally by calculating the root mean square error (rMSE) of deviations from field observations. Logistic regression was used to estimate the effects of environmental variables on the detection of buffalo herds and linear regression was used to identify predictors of larger herd sizes. A zero-inflated Poisson model produced distributions that were most consistent with expected buffalo behavior. Field data confirmed that environmental factors including season (P = 0.008), vegetation type (P = 0.002), and vegetation density (P = 0.010) were significant predictors of buffalo detection. Bachelor herds were more likely to be detected in dense vegetation (P = 0.005) and during the wet season (P = 0.022) compared to the larger mixed-sex herds. Static distribution models for African buffalo can produce biologically reasonable results but environmental factors have significant effects and therefore could be used to improve model performance. Accurate distribution models are critical for the evaluation of disease risk and to model disease transmission.

Coyotes (Canis latrans) and gray foxes (Urocyon cinereoargenteus) are abundant and widely distributed in México, with no information currently available about their spatial interactions in the country. Our objectives were to evaluate the habitat use of these species and the environmental interactions between them throughout the overlapping areas of their home ranges in temperate forests of Durango, México. We expected that their coexistence would be facilitated by the spatial segregation of their ecological niche, exhibited by the low or nil overlap between their home ranges or by differentiated habitat use. Radio-collars (VHF) were attached to nine individuals — four coyotes (two males and two females) and five gray foxes (females) — that were radio-tracked from September 2017 to August 2019. We estimated their home ranges and the size of their core areas through the minimum convex polygon and determined the extent of overlap between them. Also, we evaluated third-order habitat selection and use based on habitat availability using Manly’s habitat-selection ratios and simultaneous Bonferroni confidence intervals (95 %). The mean home range size for coyotes was larger (12.2 ± 1.74 km2) than for gray boxes (5.3 ± 0.67 km2); the interspecific mean overlap was 42 % (moderate). Of these two canids, just the gray fox showed a markedly selective habitat use. Our findings revealed a moderate overlap between the home ranges of both canids, so spatial segregation did not occur. Although a differential habitat use was observed, explaining the coexistence between these two canids in the areas where they thrive, they tend to avoid agonistic interactions.

Whilst food availability influences space use by animals, how fluctuating resources influence the location of home ranges and space use patterns is little understood. In this study, we first determined the home range of brown hyaenas (Parahyaena brunnea) living inside, and adjacent to, the Makgadikgadi Pans National Park, Botswana. We then examined home range use and how home range fidelity varied depending on the spatio‐temporal variability of available resources that were important for brown hyaenas. Finally, we determined if there was any variation in space use between male and female brown hyaenas. We found that brown hyaenas lived in well‐defined home ranges and showed strong spatial associations with other group members. Brown hyaenas shifted their seasonal home ranges to match food distribution. Hyaenas living in variable food environments demonstrated greater fluctuations in seasonal home range sizes and lower levels of home range retention than individuals from clans in more stable food environments. While home range edges remained more stable for clans located in areas with more food, they still showed a high degree of spatial plasticity in seasonal and annual movements in response to food availability and distribution over time. Clans living inside the Makgadikgadi Pans National Park did not defend an area sufficiently large to provide adequate food resources all year and individuals foraged into adjacent clan ranges when food was scarce. Hyaenas in clans outside Makgadikgadi Pans National Park lived in an area that contained adequate food resources all year. Gender did not influence space use by brown hyaenas.

We estimated home range size and habitat use of adult female moose (Alces alces) in Grims6, southcentral Sweden. Fourteen adult moose (3-8 yr old) were radiomarked and located from February 1982 through November 1985. Seasonal and annual home range sizes and habitat preferences were determined. Seasonal home range size varied. Summer home ranges were almost 2x larger than winter ranges (9.1 vs. 4.9 km2). Summer ranges constituted >70% of the annual home range. Home ranges overlapped a mean of >10% between all seasons. Annual home range averaged 12.6 km2 and contained ?2 core areas. Core areas represented a mean of 85% of all locations but only 50% of the total area. All annual home ranges overlapped with >-1 home range of other females. Females preferred clearcuts and young and medium-aged forests. Mature stands and bogs were avoided by female moose. J. WILDL. MANAGE. 52(2):336-343 The increase in the moose population in Fennoscandia during the late 1970's and early 1980's has been related to an increase in the amount and distribution of food resources caused by changes in forest management and controlled, selective hunting (Cederlund and Markgren 1986, Haagenrud et al. 1986, Stilfelt 1986). The moose population varies in density between regions and local areas. Experiences from hunters and aerial surveys have indicated that many local areas contain few moose ( 1.0/km2) (T. Thirnhuvud, Flyginventering i Vaisternorrlands iin.-Analyser och firslag till prognosf6rbaittrande Atgiirder, Grims6 Rep. 48 pp., 1983). Managers consider local moose densities to be related to hunting pressure and food distribution (Cederlund and Markgren 1986). Proper management of moose can be facilitated with a better understanding of moose distribution and home ranges. Females are the basic unit for moose management; their density and age distribution determines overall production of calves (Markgren 1969, Saether and Haagenrud 1983). Females also contribute to habitat use of offspring (Sigman 1977), determine movements to seasonal ranges (Mytton and Keith 1981, Sandegren et al. 1983), and establish home ranges of their calves (Gasaway et al. 1980, Cederlund et al. 1987). Our objectives were to (1) estimate female moose expansion of, and fidelity to, individual home ranges during different seasons and years in a high density moose population; (2) determine female moose selection of forest habitats during different seasons; and (3) provide recommendations for management unit size and forestry practices. We are grateful to P. Y. Sweanor for comments and stylistic correction of the manuscript. We thank the staff at Grims6 for radiotracking. We thank P. G. Ahlqvist for marking moose. This study was supported by the Swedish Environment Protection Board.

Island foxes (Urocyon littoralis) are currently listed as federally endangered on four of the six Channel Islands to which they are endemic. The Santa Rosa Island (SRI) population declined by 99% during the 1990’s due to non-native golden eagle (Aguila chrysaetos) predation and is currently the lowest fox population (~280) and density (0.86 foxes/km2) of any of the Channel Islands. The goals of this study were to assess new miniaturized GPS technology and to quantify home range and habitat use of the SRI population. This is only the second use of Global Positioning System (GPS) collars on Channel Island foxes and provides essential baseline data for the recovering population. These results can be used to guide management decisions and future habitat restoration efforts after the recent removal of non-native ungulates. In fall 2009, 14 GPS collars were deployed on male foxes on the east side of SRI. Nine collars and three remote download datasets were recovered in 2010. The collars’ battery life was 40% lower than expected at an average (±SE) of 16.5 ± 1.7 weeks but had high performance in precision and fix rate. Collars yielded an average of 347 ± 33 locations with a fix rate of 82.3% ± 2.1% and 88% of locations categorized as high precision. From these data, 95% minimum convex polygon (MCP) home ranges and 95% kernel density isopleth (KDI) home ranges were created. The average 95% MCP home range size was 3.39 ± 0.59km2 and the area of overlap with adjacent home ranges had a median of 5.3%. The average 95% KDI home range size was 3.82 ± 0.68km2 with a median overlap of 6.0%. These home range sizes are almost triple the size reported in other island fox studies, likely due to the low fox densities in the recovering SRI population. Habitat analysis was performed using KDI home ranges and a Euclidian distance analysis (EDA) method to assess habitat selection within the study area, the home range and the core area. Results showed selection for lupine within the study area, which no previous studies have documented. There was no significant habitat selection within the home ranges or core areas. Foxes selected for valley bottom topography and for bare and grassland habitat at night. One shortcoming of EDA is that its reliance on random points for determining second order selection can lead to unused areas being identified as selected habitat. The lack of

Many populations of the Moustached Warbler (Acrocephalus melanopogon) have suffered a noticeable decrease over the last decades. This work has the aim of estimating the home range of the Moustached Warbler and its habitat use during the reproductive season. We captured 11 males during the reproductive period with mist nets and marked them with radio transmitters. We determined the home range by calculating minimum convex polygon and kernel areas at 95% (home range) and 50% (core area). Then, to study the habitat use, we registered the proportion of the different vegetation types within these areas and carried out a compositional analysis to investigate if there is a detectable habitat preference. The results seem to indicate that the marked individuals did not show territorial behavior, given that the overlaps between home ranges and also the core areas were over 70%. The compositional analysis showed that A. melanopogon prefers tall and short reeds and mixed vegetation with rushes and bulrushes. Thus, maintaining heterogeneous and stratified vegetation would favor this species.