Spatial organization in the Ethiopian wolfCanis simensis: large packs and small stable home ranges

Space use of cougars at the northern edge of their range

The space use strategies animals use to acquire resources needed for survival and reproduction reflect life history traits and individual behaviors. For large solitary carnivores, such as cougars (Puma concolor), prey, mates, and safe habitat in which to raise offspring, are resources that influence space use. Most animal home range studies investigate differences between sexes but fail to explore the space use patterns among individuals. We first used 95% minimum convex polygon (MCP), kernel density estimate (KDE), and Brownian bridge estimator (BB), to estimate the home range of 43 cougars satellite-collared in west-central Alberta, Canada, in 2016–2018. We found that adult males (MCP = 498 km2; KDE = 623 km2; BB = 547 km2) had home ranges that were more than twice the size of those of adult females (MCP = 181 km2; KDE = 273 km2; BB = 217 km2). We then used net squared displacement, path segmentation analysis, and multi-response permutation procedure, to examine the space use patterns of 27 female and 16 male cougars. We constructed a decision tree and found that 23% of cougars were dispersers (12% of females and 44% of males), 47% were residents (58% of females and 31% of males), 9% were seasonal home range shifters (12% of females and 6% of males), and 19% shifted to a new area during the study period (19% of females and 19% of males). We learned that dispersers all were subadults, whereas all residents, seasonal shifters, and shifters, were adults, except for one subadult male. Our study provides insights on animal home ranges with methods to categorize different space use strategies which could be used to help assess the dynamics of a population.

Evidence of economical territory selection in a cooperative carnivore

As an outcome of natural selection, animals are probably adapted to select territories economically by maximizing benefits and minimizing costs of territory ownership. Theory and empirical precedent indicate that a primary benefit of many territories is exclusive access to food resources, and primary costs of defending and using space are associated with competition, travel and mortality risk. A recently developed mechanistic model for economical territory selection provided numerous empirically testable predictions. We tested these predictions using location data from grey wolves (Canis lupus) in Montana, USA. As predicted, territories were smaller in areas with greater densities of prey, competitors and low-use roads, and for groups of greater size. Territory size increased before decreasing curvilinearly with greater terrain ruggedness and harvest mortalities. Our study provides evidence for the economical selection of territories as a causal mechanism underlying ecological patterns observed in a cooperative carnivore. Results demonstrate how a wide range of environmental and social conditions will influence economical behaviour and resulting space use. We expect similar responses would be observed in numerous territorial species. A mechanistic approach enables understanding how and why animals select particular territories. This knowledge can be used to enhance conservation efforts and more successfully predict effects of conservation actions.

Hidden Long-Distance Movements by a Migratory Bird

Technology has revolutionized our ability to track animals across the globe, significantly advancing our understanding of animal movement [1, 2]. Technological and logistical challenges, however, have led to non-migratory movements that fall outside of the territory/home range paradigm, receiving less attention. This may have resulted in a widespread underestimation of the frequency and spatial scale at which animals either move outside of their territories and home ranges or adopt altogether different space-use strategies. We used a breeding-range-wide automated radio-telemetry system to track movements in a migratory songbird, the Kirtland's warbler (Setophaga kirtlandii). By attaching radio tags on the wintering grounds and relocating the same individuals on the breeding grounds, we were able to sample the population without regard to their eventual breeding status or space-use strategy. We found that a surprising proportion of breeders and most non-breeders made long-distance (5-77 km) movements during the breeding season while conspecifics remained within their small territories. Movement frequency peaked during the nestling and fledgling periods, indicating that both breeders and non-breeders were likely prospecting to inform dispersal. A literature review revealed that Kirtland's warblers moved farther than most species in absolute distances and farther than all other species relative to normal daily movements. We argue that similarly long-distance movements likely exist in many other species but have gone undetected because of technological limitations, research biases, and logistical challenges. Underestimation of the scale of these poorly understood life history behaviors has important implications for the ecology, evolution, and conservation of animals. VIDEO ABSTRACT.

Trade-offs with telemetry-derived contact networks for infectious disease studies in wildlife

Network analysis of infectious disease in wildlife can reveal traits or individuals critical to pathogen transmission and help inform disease management strategies. However, estimates of contact between animals are notoriously difficult to acquire. Researchers commonly use telemetry technologies to identify animal associations; but such data may have different sampling intervals and often captures a small subset of the population. The objectives of this study were to outline best practices for telemetry sampling in network studies of infectious disease by determining (1) the consequences of telemetry sampling on our ability to estimate network structure, (2) whether contact networks can be approximated using purely spatial contact definitions, and (3) how wildlife spatial configurations may influence telemetry sampling requirements.We simulated individual movement trajectories for wildlife populations using a home range-like movement model, creating full location datasets and corresponding "complete" networks. To mimic telemetry data, we created "sample" networks by subsampling the population (10-100% of individuals) with a range of sampling intervals (every minute to every three days). We varied the definition of contact for sample networks, using either spatiotemporal or spatial overlap, and varied the spatial configuration of populations (random, lattice, or clustered). To compare complete and sample networks, we calculated seven network metrics important for disease transmission and assessed mean ranked correlation coefficients and percent error between complete and sample network metrics.Telemetry sampling severely reduced our ability to calculate global node-level network metrics, but had less impact on local and network-level metrics. Even so, in populations with infrequent associations, high intensity telemetry sampling may still be necessary. Defining contact in terms of spatial overlap generally resulted in overly connected networks, but in some instances, could compensate for otherwise coarse telemetry data.By synthesizing movement and disease ecology with computational approaches, we characterized trade-offs important for using wildlife telemetry data beyond ecological studies of individual movement, and found that careful use of telemetry data has the potential to inform network models. Thus, with informed application of telemetry data, we can make significant advances in leveraging its use for a better understanding and management of wildlife infectious disease.

Determinants of home range size and space use patterns in a protected wolf (Canis lupus) population in the central Apennines, Italy

Large carnivores are amongst the most susceptible species to human activities, and human-modified environments pose a threat to carnivore conservation. Wolves (Canis lupus Linnaeus, 1758) in the central Apennines, Italy, have coexisted with humans since historic times and represent a good case study to assess their spatiotemporal response to anthropogenic factors. From 2008 to 2010, we investigated the spatial behavior of wolves (seven wolves in five packs and six floaters) in the Abruzzo Lazio and Molise National Park. Orographically corrected annual home ranges of resident wolf packs, estimated through the Brownian bridge movement model, averaged 104 ± 24 km2 (mean ± SD), whereas floaters used two- to fourfold larger areas (293.8–408.7 km2). We did not detect any seasonal effect on home range size, but home ranges were larger during the night and in areas of greater road density, especially during summer. By estimating core areas through an individual-based approach, we also revealed a habitat-mediated response to human presence and activity, as resident wolves preferentially established core areas at greater elevation and in the more forested and inaccessible portions of the home range.

Helminth parasites in the endangered Ethiopian wolf,Canis simensis

Ethiopian wolves,Canis simensis, are an endangered carnivore endemic to the Ethiopian highlands. Although previous studies have focused on aspects of Ethiopian wolf biology, including diet, territoriality, reproduction and infectious diseases such as rabies, little is known of their helminth parasites. In the current study, faecal samples were collected from 94 wild Ethiopian wolves in the Bale Mountains of southern Ethiopia, between August 2008 and February 2010, and were screened for the presence of helminth eggs using a semi-quantitative volumetric dilution method with microscopy. We found that 66 of the 94 faecal samples (70.2%) contained eggs from at least one group of helminths, includingCapillaria,Toxocara,Trichuris, ancylostomatids,Hymenolepisand taeniids. Eggs ofCapillariasp. were found most commonly, followed byTrichurissp., ancylostomatid species andToxocaraspecies. Three samples containedHymenolepissp. eggs, which were likely artefacts from ingested prey species. Four samples contained taeniid eggs, one of which was copro-polymerase chain reaction (copro-PCR) and sequence positive forEchinococcus granulosus, suggesting a spillover from a domestic parasite cycle into this wildlife species. Associations between presence/absence ofCapillaria,ToxocaraandTrichuriseggs were found; and egg burdens ofToxocaraand ancylostomatids were found to be associated with geographical location and sampling season.

Major histocompatibility complex diversity in the endangered Ethiopian wolf (Canis simensis)

The major histocompatibility complex (MHC) influences immune response to infection and vaccination. In most species, MHC genes are highly polymorphic, but few wild canid populations have been investigated. In Ethiopian wolves, we identified four DLA (dog leucocyte antigen)-DRB1, two DLA-DQA1 and five DQB1 alleles. Ethiopian wolves, the world's rarest canids with fewer than 500 animals worldwide, are further endangered and threatened by rabies. Major rabies outbreaks in the Bale Mountains of southern Ethiopia (where over half of the Ethiopian wolf population is located) have killed over 75% of wolves in the affected sub-populations. In 2004, following a rabies outbreak, 77 wolves were vaccinated, and 19 were subsequently recaptured to monitor the effectiveness of the intervention. Pre- and post-vaccination rabies antibody titres were available for 18 animals, and all of the animals sero-converted after vaccination. We compared the haplotype frequencies of this group of 18 with the post-vaccination antibody titre, and showed that one haplotype was associated with a lower response (uncorrected P < 0.03). In general, Ethiopian wolves probably have an adequate amount of MHC variation to ensure the survival of the species. However, we sampled only the largest Ethiopian wolf population in Bale, and did not take the smaller populations further north into consideration.

The effect of the last glacial age on speciation and population genetic structure of the endangered Ethiopian wolf (Canis simensis)

During the last glacial age, Afro-alpine habitats were widespread across the highlands of Ethiopia. A wolf-like canid ancestor is thought to have colonized this expanding habitat and given rise to a new species that was remarkably well adapted to the high altitude environment: the Ethiopian wolf Canis simensis. Here, we address the timing of genetic divergence and examine population genetic history and structure by investigating the distribution of mitochondrial DNA (mtDNA) sequence variation. The pattern of mtDNA variation and geographical distribution indicate an initial population expansion, probably immediately after divergence from the wolf-like ancestor, around 100,000 years ago. The partition of mtDNA haplotypes that followed was most likely the result of habitat reduction and fragmentation at the onset of deglaciation approximately 15,000 years ago. Phylogenetic and geographical associations suggest that the most likely genetic partitioning corresponds to three mountain areas, Arsi/Bale, Wollo/Shoa and Simien/Mt. Guna. Although there is a degree of clustering of haplotypes from both sides of the Rift Valley, the lack of reciprocal monophyly does not support the taxonomic classification of two subspecies. This study highlights the importance of populations north of the Rift Valley for the maintenance of genetic variability within the species and has consequent implications for conservation.

Potential fitness benefits of group living in the red fox, Vulpes vulpes

For species such as the red fox, spatio-temporal variation in resource availability may promote group living even when the benefits of group formation are not of significant magnitude to promote territorial expansion and delayed dispersal. In this paper we use data from an urban fox population to compare the relative benefits of dispersal and natal philopatry as routes to attaining dominant status and investigate the potential benefits of territory inheritance, alloparental care and reproduction to subdominant individuals. More offspring, of either sex, remained on their natal territory than dispersed. The annual rate of retention of dominant status and the annual mortality rate of subdominant animals was high, such that the majority of subdominant animals never became dominant. The mortality rate of dispersing individuals was also high. The relative success rate of dispersal and philopatry as routes to dominance were broadly similar, although several philopatric offspring became dominant only after their natal territory was divided: in the absence of such changes, dispersal was more likely to lead to dominant status. Thus, it is likely that some other benefit was accrued by philopatric individuals. The majority of subdominants provisioned cubs. This did not increase the number of cubs reared but reduced the level of provisioning by dominants: whether this promoted dominants' longevity is unknown. There were high levels of reproduction by subordinate females and the levels of alloparental care by subdominants of both sexes suggest that there are comparable levels of direct reproduction by subdominant males. (c) 1998 The Association for the Study of Animal Behaviour.