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Outdoor recreation, particularly in winter, causes pressure on wildlife. While many species seem to adjust well to predictable on-trail recreation activities, unpredictable off-trail activities are considered harmful. Measures to minimise human disturbance require the identification of ‘conflict-sites’ where human activities are likely to interfere with the requirements of wildlife. We used winter recreation data combined with spatial modelling to predict where recreationists move from marked trails into wildlife habitats in winter and to determine the environmental factors that trigger this off-trail behaviour. We surveyed marked winter trails in the southern Black Forest, Germany, by foot or ski for tracks of people leaving the trail, with three types of recreationists distinguished: hikers, snowshoe users and cross-country skiers. Using a maximum entropy approach, the probability of leaving the trail was modelled as a function of topographic, forest structure and tourism infrastructure variables. By combining the results with previously mapped habitat information of two disturbance sensitive species, the capercaillie Tetrao urogallus and the red deer Cervus elaphus, we identified conflict sites where mitigation measures would be most effective. All models were effective in predicting the locations where people left the trails and the three types of recreationists showed a similar pattern: the presence of closed summer trails and signposts along these trails proved to be the factors most strongly affecting the probability of leaving marked trails, followed by slope, which was negatively correlated with the probability of going off-trail. People leaving directly into the forest, not using a summer trail, were most positively influenced by the successional stages ‘regeneration’ and ‘old forest’, whereas increasing canopy cover decreased the probability of leaving the trail. The models were extrapolated to all marked trails in the study area. Locations with a high probability of people leaving the trails were identified and intersected with the previously mapped key habitats of the two wildlife species, thereby showing the locations where leaving the trail would be linked with a high potential of human-wildlife conflict. By indicating what triggers people to leave the trails, and identifying the critical locations, our results contribute to the determination of adequate management measures.
We evaluated the application of using an additive harvest mortality model (AHMM) as a harvest management strategy for northern bobwhites Colinus virginianus during the 2007/08 and 2008/09 hunting seasons in two ecoregions of Texas: the Rolling Plains (RP) and the South Texas Plains (STP). We collected field data on three study sites/ecoregion (of 400-1,900 ha each; two treatment and one control) to estimate four demographic parameters (i.e. fall and spring density, overwinter survival in the absence of hunting and harvest rate). We used these data to parameterize an AHMM (a theoretical component of sustained-yield harvest; SYH) for bobwhites and compare model-based predictions of spring bobwhite populations with field estimates. Our goal was to compare predictions from the AHMM to field estimates of spring density based on known rates of harvest. Compared to field estimates, the AHMM consistently underestimated spring population density (mean % ± SE) by 55.7 ± 17.8% (2007/08) and 34.1 ± 4.9% (2008/09) in the RP and by 26.4 ± 25.3% (2007/08) and 49.1 ± 2.1% (2008/09) in the STP. Prescribing a fall bobwhite harvest to achieve a specific, target spring density may be difficult given the wide variation in the model parameters (i.e. fall and spring density, and natural mortality) that we observed.
The Eurasian woodcock Scolopax rusticola is a valued game species in southwestern Europe, which is locally under a high hunting pressure. Disturbance due to hunting can lead to avoidance of wintering areas or have an impact on population dynamics owing to behavioural changes. We studied the impact of disturbance on 54 radio-tagged woodcocks under an experimental framework. The birds were allocated to the following three groups: simulated hunting disturbance (controlled disturbance; CD), hunted (H) and control (C). We studied the following four behavioural elements: space use, activity duration, number of commuting flights and date of spring migration departure. We found no differences in behavioural responses between the groups except for space use. A majority of CD birds used larger ranges during daytime than did H and C birds but did not change their nocturnal sites. To a large extent, this nocturnal site fidelity likely accounted for the weak disturbance effect, in so far as food intake was ensured. Our study underlines the importance of permanent meadows in the surroundings of forests to help this species to better withstand hunting disturbance.
Troy W. Grovenburg, Christopher N. Jacques, Robert W. Klaver, Christopher S. DePerno, Chad P. Lehman, Todd J. Brinkman, Kevin A. Robling, Susan P. Rupp, Jonathan A. Jenks
The use of very high frequency (VHF) radio-telemetry remains wide-spread in studies of wildlife ecology and management. However, few studies have evaluated the influence of vegetative obstruction on accuracy in differing habitats with varying transmitter types and heights. Using adult and fawn collars at varying heights above the ground (0, 33, 66 and 100 cm) to simulate activities (bedded, feeding and standing) and ages (neonate, juvenile and adult) of deer Odocoileus spp., we collected 5,767 bearings and estimated 1,424 locations (28-30 for each of 48 subsamples) in three habitat types (pasture, grassland and forest), during two stages of vegetative growth (spring and late summer). Bearing error was approximately twice as large at a distance of 900 m for fawn (9.9°) than for adult deer collars (4.9°). Of 12 models developed to explain the variation in location error, the analysis of covariance model (HT*D C*D HT*TBA C*TBA) containing interactions of height of collar above ground (HT), collar type (C), vertical height of understory vegetation (D) and tree basal area (TBA) was the best model (wi = 0.92) and explained ∼ 71% of the variation in location error. Location error was greater for both collar types at 0 and 33 cm above the ground compared to 66 and 100 cm above the ground; however, location error was less for adult than fawn collars. Vegetation metrics influenced location error, which increased with greater vertical height of understory vegetation and tree basal area. Further, interaction of vegetation metrics and categorical variables indicated significant effects on location error. Our results indicate that researchers need to consider study objectives, life history of the study animal, signal strength of collar (collar type), distance from transmitter to receiver, topographical changes in elevation, habitat composition and season when designing telemetry protocols. Bearing distances in forested habitat should be decreased (approximately 23% in our study) compared to bearing distances in open habitat to maintain a consistent bearing error across habitats. Additionally, we believe that field biologists monitoring neonate ungulates for habitat selection should rely on visual locations rather than using VHF-collars and triangulation.
Long-distance vocalizations by canids play an important role in communication among individuals, and researchers have elicited these vocalizations to estimate canid occurrence and relative abundance. We evaluated the efficacy of broadcasted coyote Canis latrans group-yip calls and gray wolf C. lupus lone howls to elicit vocal responses from 18 GPS-collared coyotes on 144 occasions in Michigan's Upper Peninsula during August-September 2009 and June-September 2010-2011. We evaluated coyote responses to each call type using mixed-effects logistic regression models with time (month), residency status (resident or transient), presence in wolf territory, sex, distance, movement and call type as fixed effects hypothesized to influence coyote vocal response rates. The individual coyote and year were included as random effects. Overall, call type, sex and presence of wolf territory did not affect coyote response rates; however, coyotes did not respond to wolf calls broadcasted at distances of > 2.0 km. Resident coyotes were three times more likely to respond than transients and the greatest overall response rates occurred in August. We conclude that eliciting coyote vocalizations where wolves are present will not bias responses, and we recommend eliciting coyote vocalizations using recorded coyote group-yip howls during July-September to estimate the species' presence or density.
The aim of our research was to investigate the relative importance of food supply, geological conditions, human activity and neighbouring badger Meles meles territories for location of badger setts in Białowieża Primeval Forest (BPF) within the boundaries of Poland (595 km2). In our study, we included 67 badger setts surveyed in the field as well as 7,563 pseudo-absence points located randomly in each subcompartment of the forest. For each point, 18 habitat and landscape variables were assessed. The data were analysed using the Random Forest model in two stages, i.e. feature selection and variable importance assessment. Our results indicate that the human-related variables for location of badger setts in BPF (strong avoidance of main roads, bimodal reaction to open and built-up areas) were of highest importance. The second most important variable was the distance to neighbouring active main setts (preference of the distance of 2 km from the nearest active main sett). The least important variables were habitat conditions affecting digging possibility and food availability, such as the presence of cambisols or fresh entic podzols made of loamy sands on ablation moraine or aeolian dunes with potential vegetation of thermophilous oak Quercus robur-hornbeam Carpinus begulus forest of fresh pine Pinus sylvestris-oak mixed forest. We conclude that large intact forest complexes function as refuge areas for badger populations if badger mortality is high in open areas relative to the benefits of wide food availability in open areas.
Activity patterns of predators are influenced by several factors including season and temperature as well as the availability of prey species. We investigated the activity of six free-living Eurasian lynx Lynx lynx (four males and two females without kittens) in the Bohemian Forest along the border between Germany and the Czech Republic. The lynx were tagged with GPS-collars with acceleration sensors in 2005, 2010 and 2011. Activity was measured every 5 minutes on 1,360 days (403,467 measurements) to detect circadian activity patterns. All lynx were predominantly crepuscular, with an average activity of 8.9 hours/day and with the lowest activity at midday. The activity patterns of male and female lynx did not differ significantly. With each 10°C increase in the mean air temperature per day, the lynx decreased their daily activity by 30 minutes. In winter, activity was concentrated at dusk. We also investigated whether lynx activity was influenced by the availability of freshly killed roe deer Capreolus capreolus, red deer Cervus elaphus or European hare Lepus europaeus. We compared the activity data of 357 days with a kill (109 recorded kills) and 316 days without a kill and calculated generalised additive mixed models. On days with a kill, the lynx were 3.3 hours/ day less active than on days without a kill. The activity on consecutive days with a killed prey did not differ. The pattern of activity on days with a kill differed little from the pattern of activity on days without a kill.
The role of predation in ecological systems has received considerable attention in scientific literature and is one of the most important, yet least understood aspects of carnivore ecology. Knowledge of factors that improve our ability to detect predation events using animal telemetry data could be used to develop strategies to reduce time and resources required to obtain reliable kill estimates. Using Global Positioning System telemetry-collars, we investigated 246 bobcat Lynx rufus location clusters to identify white-tailed deer Odocoileus virginianus kill sites in the Upper Peninsula of Michigan, USA, during May-August, 2009-2011. We documented kills of white-tailed deer at 42 location clusters. We used logistic regression and Akaike Information Criterion for small samples to identify factors (i.e. number of locations in cluster, time from cluster formation to investigation, time of day and land cover) that may influence bobcat behaviour and our ability to detect white-tailed deer kill sites. Clusters with more locations and the search of clusters within 14 days after cluster formation increased odds of detecting bobcat kill sites. The best-performing model was 67% accurate overall and identified 34% of kill sites and 75% of non-kill sites. Applying our best-performing model with the optimal cut-off value would result in a twofold increase in the identification of white-tailed deer kill sites reducing time and effort to find a similar number of kill sites without models by half. Identifying factors that improve our ability to identify bobcat kill sites can reduce field effort and search time.
Predation risk may affect space use and foraging patterns of prey animals, with strong down-stream effects on diet composition and ecological interactions. Wild boar Sus scrofa is a notorious crop raider but also a popular game species, yet little is known about how risk perception of human hunting affects wild boar space use. We studied the effects of human hunting on the movement of GPS-collared female wild boar. We found that the hunting method affected whether the wild boar fled or hid. After fleeing into refuge ranges, wild boar moved less and preferred habitats that provided cover and forage such as mast or crops. This suggests that the wild boar tried to reduce the risk of being detected, and possibly also that they avoided competition with resident wild boar in the refuge by using forage that could not be monopolised. The type of hunting thus strongly affected the type of avoidance behaviour displayed by wild boar, with implications for their movement and space use. This suggests that adjusting hunting method to season could be an important management tool for minimising crop losses.
The successful management of large herbivores requires the monitoring of a set of indicators of ecological change (IEC) describing animal performance, herbivore impact on habitat and relative animal abundance. Roaring counts during the rut have often been used to assess the abundance of red deer Cervus elaphus populations, but a formal evaluation of this method is still lacking. In this paper, we examined the usefulness of the number of red deer recorded during roaring counts for managing red deer populations. Using standardised spotlight counts applied for the monitoring of red deer at La Petite Pierre, France, as a reference method, we found that roaring counts did not correlate with spotlight counts. Moreover, we did not find any evidence that roaring counts decreased with increasing number of male and female red deer harvested in the reserve during the previous hunting season. We thus conclude that managers should not rely on roaring counts for managing red deer populations.
To better understand the future spread of chronic wasting disease, we conducted a genetic assessment of mule deer Odocoileus hemionus population structure across the state of Montana, USA. Individual based analyses were used to test for population structure in the absence of a priori designations of population membership across the sampling area. Samples from the states of Wyoming, Colorado and Utah were also included in the analysis to provide a geographic context to the levels of population structure observed within Montana. Results showed that mule deer across our entire study region were characterized by weak isolation by distance and a lack of spatial autocorrelation at distances > 10 km. We found evidence for contemporary male bias in dispersal, with female mule deer exhibiting higher mean individual pairwise genetic distance than males. We tested for potential homogenizing effects of past translocations within Montana, but were unable to detect a genetic signature of these events. Our results indicate high levels of connectivity among mule deer populations in Montana and suggest few, if any, detectable barriers to mule deer gene flow or chronic wasting disease transmission.
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