Home Range Overlap Research Articles

교외지역에 서식하는 Myotis aurascens의 주간휴식지 선택 및 행동권 크기

Between July and October 2011, radio-tracking was used to analyze the characteristics of home ranges and day roosts of Myotis aurascens by using 3 individuals (male: 2, female: 1). Bat capturing was conducted at a bridge and a nearby forest in Ulju-gun, Ulsan-si. We attached radio transmitters (0.32 g) to the bats and monitored them by using a radio receiver with a Yagi antenna. Home-range analysis of M. aurascens by using 100% minimum convex polygon (MCP) and 95% MCP showed an average of 106.5 ha and 89.3 ha, respectively, and 50% kernel home range (KHR) showed an average of 8.4 ha. Home range overlap of the 3 bats was observed at the bridge and at nearby water bodies as the core areas, and the size of the home range overlap was 7.3 ha by 100% MCP, 5.9 ha by 95% MCP, and 1.6 ha by 50% KHR. The home range for each bat consisted of the main foraging sites, and the types of foraging sites were similar. M. aurascens-01(M-01) used the bridge and nearby water bodies as the nightly main core areas, M. aurascens-02(M-02) used rice fields and water bodies adjacent to the forest as core areas, and M. aurascens-03(M-03) used water bodies and resident areas as core areas. Although rice fields and resident sites represented the core areas of the home ranges of M-02 and M-03, habitat use was the highest near water bodies as the core area for all the 3 bats. The types of day roosts in this study were a wooden house, canopies of a broad-leaved woodland, and banks of rice fields. The roosts in the wooden house and canopies of the broad-leaved woodland were located within the forest, and the roost in the banks of rice fields was also adjacent to the forest. Our results revealed that the main home range and foraging sites of M. aurascens were located near water bodies as the core area, and forests and places adjacent to the forests were used as day roosts.

Spatial Ecology of the Critically Endangered Fijian Crested Iguana, Brachylophus vitiensis, in an Extremely Dense Population: Implications for Conservation

The Critically Endangered Fijian crested iguana, Brachylophus vitiensis, occurs at extreme density at only one location, with estimates of >10,000 iguanas living on the 70 hectare island of Yadua Taba in Fiji. We conducted a mark and recapture study over two wet seasons, investigating the spatial ecology and intraspecific interactions of the strictly arboreal Fijian crested iguana. This species exhibits moderate male-biased sexual size dimorphism, which has been linked in other lizard species to territoriality, aggression and larger male home ranges. We found that male Fijian crested iguanas exhibit high injury levels, indicative of frequent aggressive interactions. We did not find support for larger home range size in adult males relative to adult females, however male and female residents were larger than roaming individuals. Males with established home ranges also had larger femoral pores relative to body size than roaming males. Home range areas were small in comparison to those of other iguana species, and we speculate that the extreme population density impacts considerably on the spatial ecology of this population. There was extensive home range overlap within and between sexes. Intersexual overlap was greater than intrasexual overlap for both sexes, and continuing male-female pairings were observed among residents. Our results suggest that the extreme population density necessitates extensive home range overlap even though the underlying predictors of territoriality, such as male biased sexual size dimorphism and high aggression levels, remain. Our findings should be factored in to conservation management efforts for this species, particularly in captive breeding and translocation programs.

Home range extension and overlap of the Ornate Tinamou (Nothoprocta ornata) in an Andean agro-ecosystem

Very little is known about the home range and movement patterns of tinamous. The Ornate Tinamou (Nothoprocta ornata), a species of the central Andes that is important for cynegetic and biomonitoring purposes, was previously reported to have a very small territory (2.43 ha). This was based solely on field observations. In order to gain a better understanding of the movement patterns, home range size, and home range overlap of this species, we radio tracked 12 adult individuals in an Andean agro-ecosystem for a full year. The birds remained within their home ranges all year; 100% MCP (minimum convex polygon) home ranges were 43.8 ± 21.6 ha (22–85 ha), 95% kernel home ranges were 58.8 ± 31.9 ha (25–118 ha) and 50% kernel core areas were 15.3 ± 8.9 ha (6–33 ha). Only two birds, probably sub-adults, showed extensive movement patterns before their death. Individuals overlapped their home ranges extensively (from 30–98% with 2–3 tagged individuals), but these values were probably higher because a small proportion of the population was tagged. No sexual differences were detected in home range size or overlap. Our results support the usefulness of Ornate Tinamou as a sentinel species in biomonitoring studies and highlight the need for further research into the philopatric and dispersion behavior of juveniles before planning cynegetic strategies.

Happily together forever: temporal variation in spatial patterns and complete lack of territoriality in a promiscuous rodent

AbstractThe availability of resources, their effect on population density and territoriality, and the ways in which these factors are interwoven with mating systems are important determinants of small mammal space use. It is often difficult to study these patterns in an integrated way, however, especially because long‐term data are needed but not readily available. In this paper, we investigate effects of population density, season and breeding status on home range patterns of the promiscuous rodent Mastomys natalensis using monthly capture‐mark‐recapture data collected over 17 years in a 3‐ha grid. Home ranges were estimated using minimum convex polygons bounded by trap locations, and home range overlap and visitation rates were calculated as a measure of territoriality. As higher population densities coincide with increased resource availability, we predicted that home range sizes would correlate negatively with density. Furthermore, as M. natalensis is promiscuous and population densities are generally high, we predicted that territoriality would be low, and home range overlap would therefore be high. Contrary to expectations the home ranges of female adults increased with population density, although those of male adults and subadults followed the expected decrease. Home range overlap and visitation rates were generally high, and increased significantly with population density. More importantly, they were never lower than those of simulated datasets consisting of randomly moved home ranges. These results therefore suggest that M. natalensis displays a complete lack of territoriality that is rarely seen in small mammals but still meets predictions based on knowledge of density and mating system.

Genetic structure, spatial organization, and dispersal in two populations of bat‐eared foxes

We incorporated radio-telemetry data with genetic analysis of bat-eared foxes (Otocyon megalotis) from individuals in 32 different groups to examine relatedness and spatial organization in two populations in South Africa that differed in density, home-range sizes, and group sizes. Kin clustering occurred only for female dyads in the high-density population. Relatedness was negatively correlated with distance only for female dyads in the high-density population, and for male and mixed-sex dyads in the low-density population. Home-range overlap of neighboring female dyads was significantly greater in the high compared to low-density population, whereas overlap within other dyads was similar between populations. Amount of home-range overlap between neighbors was positively correlated with genetic relatedness for all dyad-site combinations, except for female and male dyads in the low-density population. Foxes from all age and sex classes dispersed, although females (mostly adults) dispersed farther than males. Yearlings dispersed later in the high-density population, and overall exhibited a male-biased dispersal pattern. Our results indicated that genetic structure within populations of bat-eared foxes was sex-biased, and was interrelated to density and group sizes, as well as sex-biases in philopatry and dispersal distances. We conclude that a combination of male-biased dispersal rates, adult dispersals, and sex-biased dispersal distances likely helped to facilitate inbreeding avoidance in this evolutionarily unique species of Canidae.

Simultaneous GPS tracking reveals male associations in a solitary carnivore

In hypercarnivorous species, females have large spatial requirements to meet their nutritional needs, and food competition among females is intense. As a result, females are typically solitary and territorial, and solitary males compete for access to dispersed females. Yet, largely anecdotal reports indicate that facultative male sociality may be more common in solitary carnivores than previously thought. We studied spatial interactions among fossas (Cryptoprocta ferox), Madagascar's largest carnivore, using simultaneous GPS tracking of 13 adult individuals to determine patterns of sex-specific spatial distribution and sociality. Male home ranges were larger than those of females, male home ranges overlapped more with those of other males than those of females with other females. Whereas some males were solitary, a subset of adult males was found to have very high home range overlap, high rates of co-location within <50 m, low minimum inter-individual distances, and significantly positive “dynamic interaction”. These associated dyads sometimes, but not always, were close relatives. The fact that solitary and associated males coexist in this population raises interesting questions concerning constraints and flexibility of social tolerance. This study yielded preliminary indications that female distribution appears to be primarily structured by resource competition, whereas male sociality seems to depend on demographic chance events, yet unknown proximate determinants of social tolerance, and it is associated with somatic and reproductive advantages. Male associations among carnivores are therefore more widespread and appear to be based on a wider range of factors than previously thought.

Multi‐trophic resource selection function enlightens the behavioural game between wolves and their prey

1. Habitat selection strategies translate into movement tactics, which reckon with the predator-prey spatial game. Strategic habitat selection analysis can therefore illuminate behavioural games. Cover types at potential encounter sites (i.e. intersections between movement paths of predator and prey) can be compared with cover types available (i) within the area of home-range-overlap (HRO) between predator and prey; and (ii) along the path (MP) of each species. Unlike the HRO scale, cover-type availability at MP scale differs between interacting species due to species-specific movement decisions. Scale differences in selection could therefore inform on divergences in fitness rewarding actions between predators and prey. 2. We used this framework to evaluate the spatial game between GPS-collared wolves (Canis lupus) versus caribou (Rangifer tarandus), and wolf versus moose (Alces alces). 3. Changes in cover-type availability between HRO and MP revealed differences in how each species fine-tuned its movements to habitat features. In contrast to caribou, wolves increased their encounter rate with regenerating cuts along their paths (MP) relative to the HRO level. As a consequence, wolves were less likely to cross caribou paths in areas with higher percentage of regenerating cuts than expected based on the availability along their paths, whereas caribou had a higher risk of intersecting wolf paths by crossing these areas, relative to random expectation along their paths. Unlike for caribou, availability of mixed and deciduous areas decreased from HRO to MP level for wolves and moose. Overall, wolves displayed stronger similarities in movement decisions with moose than with caribou, thereby revealing the focus of wolves on moose. 4. Our study reveals how differences in fine-scale movement tactics between species create asymmetric relative encounter probabilities between predators and prey, given their paths. Increase in relative risk of encounter for prey and decrease for predators associated with specific cover types emerging from HRO to MP scale analysis can disclose potential weaknesses in current movement tactics involved the predator-prey game, such as caribou use of cutovers in summer-autumn. In turn, these weaknesses can inform on subsequent changes in habitat selection tactics that might arise due to evolutionary forces.

Spatial dichotomy of sociality in the A frican ice rat

Sociality is environmentally and phylogenetically determined and can vary intraspecifically and interspecifically. We investigated the reasons for group living in the African ice rat Otomys sloggetti robertsi, a diurnal, herbivorous, non-hibernating murid rodent, endemic to the sub-alpine and alpine regions of the southern African Drakensberg and Maluti mountains. We expected ice rats to be group living, nesting communally in underground burrows. We documented the spatial organization and social behaviour of free-living ice rats through direct observations and experimental manipulations. Colonies comprised 4–17 adults of both sexes. Members of a colony had a high degree of spatial home-range overlap but no temporal overlap because interactions between members were rare aboveground. Individuals experimentally displaced within their own colony were attacked by members of their own colony and were treated in the same way as strangers from other colonies. Members of a colony competed aggressively for prized food, particularly in winter. Ice rats displayed a vertical spatial separation in social behaviour, from huddling and tolerance belowground to solitary foraging and mutual avoidance aboveground. Such a dichotomy in sociality reflects the compromise between the benefits of social thermoregulation and burrow sharing on the one hand and the constraints of competing for resources, mainly food, on the other. Such a compromise may ultimately be related to the poor physiological adaptation of ice rats to the cold environments they inhabit.

Spatial use and interaction of the invasive raccoon dog and the native red fox in Central Europe: competition or coexistence?

The main objective was to discover extent of interference and/or exploitative competition between the native red fox (Vulpes vulpes) and the introduced, invasive raccoon dog (Nyctereues proconoides) in the intensively used, agricultural landscape of northeast Germany (Mecklenburg-Western Pomerania) using very high frequency (VHF) radio telemetry. We recorded location data for 12 foxes and 16 raccoon dogs between July 2004 and December 2006. Species had similar average home range sizes estimated in each season (K95). Home ranges of adjacent raccoon dogs and foxes overlapped from 0.5 to 74.5 % with a mean of 26.4 %. We found a significantly different home range overlap index between the species showing that raccoon dog ranges shifted between seasons to a greater extent than red fox ranges. The raccoon dog differed significantly from the red fox in its use of habitat types, preferring dense vegetation cover and avoiding open areas. The red fox displayed less preference for or avoidance of specific habitat types. Moreover, an almost neutral inter-specific interaction index ranging from −0.12 to 0.12 indicates that raccoon dogs and red foxes ignored each other. It is concluded that widespread and available resources and differences in spatial use patterns prevent competition between red foxes and raccoon dogs in the agricultural landscape of northeast Germany.

Between-group contest competition among tufted capuchin monkeys, Sapajus nigritus, and the role of male resource defence

Between-group contest competition and the relative importance of male resource defence have recently been suggested to have been previously underestimated. When males contribute to the defence of group-controlled resources, the quality of the home range may depend on the resource-holding potential of resident males. Among Argentine tufted capuchin monkeys, resident males defend access to high-quality food resources. Here I investigate consequences of this male–male cooperation for intergroup dominance relationships and home range quality. I recorded ranging behaviour for four habituated groups in Iguazú National Park to identify home ranges and core areas, and measured the availability of food species within botanical plots placed in these areas. I recorded the location and outcome of intergroup encounters and fitted predictive models using generalized estimating equations to assess the relative importance of male group size and location on the outcome, before performing linear mixed-effects modelling to identify long-term benefits of winning encounters. Relative male group size was the most important factor in determining the winner of encounters, outweighing the competitive advantage of ownership. The density of food species within the core area was not affected by the group's competitive ability, but core area size increased with male group size. Moreover, dominant groups were better able to defend their core area, and adjusting for the degree of home range overlap revealed that dominant groups may have higher per capita access to food. These results suggest that male–male cooperation in defence of food resources could ultimately increase female reproductive success. ► I investigated intergroup dominance relationships and home range quality in tufted capuchins. ► Both sexes participated in intergroup aggression, but only male group size affected the outcome. ► There was no evidence of a ‘home field advantage’ favouring small groups near the centre of their home range. ► Large male group size increased home range exclusivity and per capita access to food resources.

Joint Space Use in a Parthenogenetic Armenian Rock Lizard (Darevskia armeniaca) Suggests Weak Competition among Monoclonal Females

According to kin selection theory, competition among monoclonal animals must be lower than between unrelated individuals. Thus, we propose that home range and core area overlap in parthenogenetic lizards will be broader than female range overlap in similar gonochoristic species. To test this hypothesis, we examined home range locations and space use of parthenogenetic Armenian Rock Lizards (Darevskia armeniaca) and compared them with home range locations and space use of gonochoristic species. We demonstrated that parthenogenetic Rock Lizards have a total range structure typical of insectivorous lizards, consisting of a sally zone, a home range, and one or more core areas. Some core areas contained activity centers, associated strongly with key basking sites and shelters. Provisional residents were found within the same range for 1 or 2 years, whereas wanderers visited study sites for 1 or 2 weeks per season. Settlement structure varied greatly among years. Home ranges, core areas, and even activity centers and basking sites of parthenogenetic females overlapped extensively, unlike in females of nonparthenogenic species. Monoclonal origins and high level of relatedness within unisexual species are possible explanations of the extended range overlap among parthenogenetic females.

Population ecology of vervet monkeys in a high latitude, semi-arid riparian woodland

Narrow riparian woodlands along non-perennial streams have made it possible for vervet monkeys to penetrate the semi-arid karoo ecosystem of South Africa, whilst artificial water points have more recently allowed these populations to colonize much more marginal habitat away from natural water sources. In order to better understand the sequelae of life in these narrow, linear woodlands for historically ‘natural’ populations and to test the prediction that they are ecologically stressed, we determined the size of troops in relation to their reliance on natural and artificial water sources and collected detailed data from two river-centred troops on activity, diet and ranging behaviour over an annual cycle. In comparison to other populations, our data indicate that river-centred troops in the karoo were distinctive primarily both for their large group sizes and, consequently, their large adult cohorts, and in the extent of home range overlap in what is regarded as a territorial species. Whilst large group size carried the corollary of increased day journey length and longer estimated interbirth intervals, there was little other indication of the effects of ecological stress on factors such as body weight and foraging effort. We argue that this was a consequence of the high density of Acacia karroo, which accounted for a third of annual foraging effort in what was a relatively depauperate floristic habitat. We ascribed the large group size and home range overlap to constraints on group fission.Conservation implications: The distribution of group sizes, sampled appropriately across habitats within a conservation area, will be of more relevance to management than average values, which may be nothing more than a statistical artefact, especially when troop sizes are bimodally distributed.

White-lipped peccary home-range size in a protected area and farmland in the central Brazilian grasslands

White-lipped peccaries (Tayassu pecari) are important seed predators and dispersers throughout the Neotropics. Because they occur in groups as large as 300 individuals, they need large areas to persist. We investigated homerange size and overlap of 13 groups using radiotelemetry data from 3 years of monitoring in the Emas National Park and surrounding farmland in central Brazil. Average home-range sizes were 1,710.64 ha for 50% of the locations and 8,659.99 ha for 95% based on minimum convex polygons and 790.38 ha for 50% of the locations and 7,986.92 ha for 95% based on the fixed kernel estimator. Home-range size did not correlate with group size, the monitoring period, or the number of locations obtained. Home ranges were larger during the wet season than the dry season. Average home-range overlap among groups was 31%; there were no significant differences in overlap between seasons. Home ranges varied seasonally, most likely in response to the dynamic landscape of crop plantations surrounding the park. Although the peccaries fared well in the heterogeneous agricultural landscape surrounding the park, conflict with farmers due to crop damage and landscape changes due to expansion of sugarcane plantations need to be addressed by conservation strategies.

Space-use scaling and home range overlap in primates.

Space use is an important aspect of animal ecology, yet our understanding is limited by a lack of synthesis between interspecific and intraspecific studies. We present analyses of a dataset of 286 estimates of home range overlap from 100 primate species, with comparable samples for other space-use traits. To the best of our knowledge, this represents the first multispecies study using overlap data estimated directly from field observations. We find that space-use traits in primates are only weakly related to body mass, reflecting their largely arboreal habits. Our results confirm a theory that home range overlap explains the differences in allometric scaling between population density and home range size. We then test a suite of hypotheses to explain home range overlap, both among and within species. We find that overlap is highest for larger-bodied species living in large home ranges at high population densities, where annual rainfall is low, and is higher for arboreal than terrestrial species. Most of these results are consistent with the economics of resource defence, although the predictions of one specific theory of home range overlap are not supported. We conclude that home range overlap is somewhat predictable, but the theoretical basis of animal space use remains patchy.

Are Mixed-Species Bird Flocks Stable through Two Decades?

The stability of tropical systems has been hypothesized to explain the evolution of complex behavioral interactions among species. We evaluate the degree to which one highly evolved social system, mixed-species flocks, are stable in space and time in French Guiana, where flocks were characterized 17 years apart. These flocks are led by alarm-calling "sentinels," which may benefit from food flushed by other "beater" species. Using null models, we found that flock roost sites, home range overlap, and composition were more similar than expected by chance; home ranges were nearly identical between the two time periods. Such extremely stable conditions may be essential for the evolution and maintenance of the sentinel-beater system that appears to characterize some flocks. These results may reflect an evolutionarily stable strategy among potentially interdependent species within mixed-species flocks, where home ranges contribute to stability by being far larger than the most common local disturbances in the forest.

Does Learning or Instinct Shape Habitat Selection?

Habitat selection is an important behavioural process widely studied for its population-level effects. Models of habitat selection are, however, often fit without a mechanistic consideration. Here, we investigated whether patterns in habitat selection result from instinct or learning for a population of grizzly bears (Ursus arctos) in Alberta, Canada. We found that habitat selection and relatedness were positively correlated in female bears during the fall season, with a trend in the spring, but not during any season for males. This suggests that habitat selection is a learned behaviour because males do not participate in parental care: a genetically predetermined behaviour (instinct) would have resulted in habitat selection and relatedness correlations for both sexes. Geographic distance and home range overlap among animals did not alter correlations indicating that dispersal and spatial autocorrelation had little effect on the observed trends. These results suggest that habitat selection in grizzly bears are partly learned from their mothers, which could have implications for the translocation of wildlife to novel environments.

Marten space use and habitat selection in managed coniferous boreal forests of eastern Canada

AbstractEffects of habitat loss and fragmentation on the behavior of individual organisms may have direct consequences on population viability in altered forest ecosystems. The American marten (Martes americana) is a forest specialist considered as one of the most sensitive species to human‐induced disturbances. As some studies have shown that martens cannot tolerate &gt;30–40% clear‐cuts within their home range, we investigated marten space use (home range size and overlap) and habitat selection in landscapes fragmented by 2 different patterns of timber harvesting in the black spruce boreal forest: dispersed‐cut landscapes (10–80 ha cut‐blocks) and clustered‐cut landscapes (50–200 ha cut‐blocks). We installed radio‐collars on female martens and determined 20 winter home ranges (100% minimum convex polygons and 60–90% kernels) in dispersed‐cut (n = 8) and clustered‐cut (n = 12) landscapes. Home range size was not related to the proportion of clear‐cuts (i.e., habitat loss), but rather to the proportion of mixedwood stands 70–120 years old. However, female body condition was correlated to habitat condition inside their home ranges (i.e., amount of residual forest and recent clear‐cuts). At the home range scale, we determined that mixedwood forests were also among the most used forest stands and the least used were recent clear‐cuts and forested bogs, using resource selection functions. At the landscape scale, home ranges included more mixedwood forests than random polygons and marten high activity zones were composed of more residual forest and less human‐induced disturbances (clear‐cuts, edges, and roads). These results suggest that mixedwood forests, which occupy approximately 10% of the study area, play a critical role for martens in this conifer‐dominated boreal landscape. We recommend permanent retention or special management considerations for these isolated stands, as harvesting mixedwood often leads to forest composition conversion that would reduce the availability of this highly used habitat. © The Wildlife Society, 2013

Genetic relatedness does not predict racoon social network structure

Social assortativity, preferentially associating with certain individuals, is a widespread behaviour among a diverse range of taxa. Animals often choose to associate with other individuals based on characteristics such as sex, age, body size, rank and genetic relatedness. These preferences can scale up to shape the overall social structure of an animal group or population. We investigated possible factors that might shape the social network structure of common racoons, Procyon lotor, in a high-density urban population in Cook County, Illinois, U.S.A. Racoon associations were recorded using proximity detecting radiocollars that recorded when individuals came within 1–1.5 m of each other. In addition, dyadic measures of home range overlap and genetic relatedness were calculated for all individuals included in our study. We used multiple regression quadratic assignment procedures to determine what factors influenced the structure of racoon association networks. The only variable that positively influenced racoon social structure was male–male homophily, which is consistent with previous studies that documented frequent social interactions between adult male racoons. Genetic relatedness had no effect on racoon social networks and there was no evidence that males or females preferentially associated with close relatives, despite the presence of kin in the population. This pattern, that kinship does not play a significant role in shaping social structure, is strikingly unusual among mammals and is not consistent with many socioecological models. Although racoon individuals showed strong social partner preferences, it is unclear what factors drove these choices. This unpredictability in partner choice shaped the structure of the racoon social networks and has important implications for disease transfer in this widespread animal vector.

Differences in brushtail possum home-range characteristics among sites of varying habitat and population density

Context In New Zealand, the Australian brushtail possum is a pest, because this species preys on native birds and transmits bovine tuberculosis (bTB) to livestock. Previous studies on possums have shown that home-range characteristics differ depending on habitat and/or population density. However, direct comparisons between studies are limited because of the use of differing monitoring techniques, some of which are now out-dated and imprecise. Understanding how possum ranging behaviour varies in response to habitat and density may allow the development of more effective and site-specific control operations. For example, variations in home-range characteristics (e.g. home-range overlap with conspecifics) among populations may mean that bTB transmission risk is not uniform among populations, resulting in the need for some sites to be prioritised for control over others. Aims To investigate whether home-range characteristics varied among three sites of differing habitat and population density, and investigate whether possum home-range characteristics varied between males and females. Methods Global Positioning System (GPS)- and VHF-tracking were used to compare possum home-range characteristics among three sites. Two sites were within pine (Pinus radiata) habitat and had low-density possum populations, and one site was within oak (Quercus robur) and sycamore (Acer pseudoplatanus) habitat, and had a higher-density possum population. Key results Possum home-range characteristics did not vary between the two low-density sites. However, these populations exhibited considerably larger home-range sizes and home-range overlap between pairs of collared possums than did the high-density population. In addition, the low-density populations used more dens and changed these more often. Across all sites, there were generally no intersexual differences in home-range characteristics. Key conclusions The present research highlights that the home-range characteristics of possums can vary among populations, depending on habitat and/or population density. Implications Further research into the drivers of possum home-range characteristics would be beneficial to allow identification of how spatial behaviour is likely to vary depending on habitat and density. This would allow the design of more targeted and therefore effective control strategies that account for these variations in behaviour, such as using a larger spatial scale of control devices where possums are known to range further.

Sex difference in the communicatory significance of localized defecation sites in Arabian gazelles (Gazella arabica)

Mammalian scent marking in localized defecation sites (latrines) has often been interpreted in the context of (male) territory defense. However, latrines could have different functions in males and females, especially where territorial males monopolize groups of females with stable social alliances and pronounced home range overlap. We investigated the communicatory significance of latrines in wild Arabian gazelles (Gazella arabica) and assessed the spatial distribution of latrines within home ranges. Latrine density and utilization was highest in the center of female group home ranges, and less frequent in peripheral home range sections, pointing towards communication within groups rather than towards territoriality. When considering male home ranges, latrine densities and utilization were higher in non-overlap zones, contradicting a territorial function. This pattern appears to be caused by more females than territorial males per given area establishing latrines. A subsequent survey of latrine utilization, based on camera trapping, suggests that males use latrines for territory defense: males visited latrines in overlap zones disproportionally more often than females, and successions of two males prevailed. Our study thus highlights that male territorial marking can be masked when males and females use the same marking system for different purposes.