Summary1. Winter tourism in the European Alps has developed rapidly over the past few decades, leading to the expansion of ski resorts, growing numbers of visitors and a massive increase in snow sport activities such as free-ride skiing and snowboarding, backcountry skiing and snowshoeing. Wildlife is often disturbed by these largely unpredictable activities, and animals may have limited opportunities to adapt. Mountain hares Lepus timidus are affected by this increase in alpine tourism, but their physiological and behavioural reactions to tourist activity are still unknown. 2. We measured the levels of faecal glucocorticoid metabolites (GCM) in wild mountain hares living in areas that had no, medium or high levels of tourist activity during winter in 2011. Furthermore, we compared the changes in GCM excretion, behaviour and food intake of six captive mountain hares following predator challenge experiments from early to mid-winter. 3. Our field results showed that GCM excretion is positively correlated with increased tourism intensity. In the predator challenge experiments, hares spent less time resting and grooming (including re-ingesting faecal pellets) during and after the stress treatments. These stress events lead to higher energy demands due to flushing, increased GCM levels, and disrupted the energy intake that hares derive from faeces. 4. We conclude that mountain hares living in areas with frequent human winter recreational activities show changes in physiology and behaviour that demand additional energy in winter, when access to food resources is limited by snow. 5. Synthesis and applications. To bring down the frequency of stress threats for mountain hares, we recommend that managers keep forests inhabited by mountain hares free of tourism infrastructure and retain undisturbed forest patches within skiing areas. Other species such as black grouse Tetrao tetrix and/or capercaillie Tetrao urogallus are also likely to benefit from such management activities because they share similar habitat requirements with mountain hares.

The development and evaluation of a reliable noninvasive genetic sampling (NIGS) is a crucial step towards accurately and reliably estimating population size for the long-term monitoring of wildlife species. We used NIGS data to obtain population density estimates of a mountain hare (Lepus timidus) population in the Swiss Alps. We evaluated and compared the effectiveness of systematic and opportunistic NIGS and their combination in spring 2014. Extraction success rate of DNA from faeces, hair and urine samples, their age-dependent variation as well as the completeness of microsatellite genotyping data were used as measures of effectiveness. We applied a spatially explicit capture-recapture (SECR) approach to estimate the minimum population size. We found that the extraction success of faecal samples decreased with the time since excretion and that urine and hair samples mostly yielded insufficient DNA for the successful genotyping of individuals. Mountain hare faeces up to 5 days old are most appropriate for NIGS because the risk of unsuccessful DNA extraction or genotyping errors/failure is considerably lower in these samples. Systematic sampling revealed more genotypes than opportunistic sampling, but the latter resulted in higher numbers of recapture and thus, increased the spatial resolution of the data. Depending on the sampling design, the population density estimates ranged from 3.2 to 3.6 mountain hares per 100 ha. This study informs ecologists and wildlife managers about suitable survey techniques for the monitoring of free-ranging lagomorph populations and addresses important principles for the development of accurate survey methods for other elusive wildlife species that inhabit difficult, mountainous terrain.

Alpine and Arctic species are considered to be particularly vulnerable to climate change, which is expected to cause habitat loss, fragmentation and-ultimately-extinction of cold-adapted species. However, the impact of climate change on glacial relict populations is not well understood, and specific recommendations for adaptive conservation management are lacking. We focused on the mountain hare (Lepus timidus) as a model species and modelled species distribution in combination with patch and landscape-based connectivity metrics. They were derived from graph-theory models to quantify changes in species distribution and to estimate the current and future importance of habitat patches for overall population connectivity. Models were calibrated based on 1,046 locations of species presence distributed across three biogeographic regions in the Swiss Alps and extrapolated according to two IPCC scenarios of climate change (RCP 4.5 & 8.5), each represented by three downscaled global climate models. The models predicted an average habitat loss of 35% (22%-55%) by 2100, mainly due to an increase in temperature during the reproductive season. An increase in habitat fragmentation was reflected in a 43% decrease in patch size, a 17% increase in the number of habitat patches and a 34% increase in inter-patch distance. However, the predicted changes in habitat availability and connectivity varied considerably between biogeographic regions: Whereas the greatest habitat losses with an increase in inter-patch distance were predicted at the southern and northern edges of the species' Alpine distribution, the greatest increase in patch number and decrease in patch size is expected in the central Swiss Alps. Finally, both the number of isolated habitat patches and the number of patches crucial for maintaining the habitat network increased under the different variants of climate change. Focusing conservation action on the central Swiss Alps may help mitigate the predicted effects of climate change on population connectivity.

In this study, we evaluated a non-invasive method for measuring glucocorticoid metabolites (GCM) in the Mountain hare (Lepus timidus). An adrenocorticotrophic hormone challenge test was performed in order to select an appropriate enzyme immunoassay (EIA) to measure faecal GCM. Finally, an 11-oxoaetiocholanolone EIA and a 5α-pregnane-3β,11β,21-triol-20-one EIA were chosen. Both assays showed small fluctuations in baseline values and a clear response after stimulation of the adrenocortical activity. To test the stability of faecal metabolites under field conditions, the effects of different storage conditions and periods on GCM concentrations were examined. The assays revealed low fluctuations in metabolite concentrations within the storage period of 12, 24, 48 and 72 h, both at ambient temperatures of 10°C and 25°C, respectively. A washing-out effect of water was found for both assays, which must be taken into account in field studies. The results indicate that this non-invasive method can be used to evaluate glucocorticoid levels of free-ranging Mountain hares.

Hopkins’ Bioclimatic Law predicts geographical patterns in phenological timing by establishing a correspondence between latitudinal and altitudinal gradients. First proposed for key phenological events of plants, such as leaf sprouting or flowering dates, this law has rarely been used to assess the geographical equivalence of key life‐history traits of mammals. We hypothesize that (H1) parturition dates of European roe deer Capreolus capreolus are delayed and more synchronized at higher latitudes and altitudes, (H2) parturition timing varies along latitudinal and altitudinal gradients in a way that matches the Hopkins’ Bioclimatic Law and (H3) females adjust parturition timing to match the period of high energy demand with peak resource availability. We used parturition dates of 7,444 European roe deer from Switzerland to assess altitudinal variation in birth timing and synchrony from 288 to 2,366 m a.s.l. We then performed a literature survey to compare altitudinal results with those from different populations along the species’ latitudinal range of distribution. Finally, we performed spatial analysis combining our highly resolved altitudinal data on parturition dates with plant phenology data. As expected, parturition dates were delayed with increasing latitude and altitude. This delay matched the Bioclimatic Law, as the effect of 1º increase in latitude was similar to 120 m increase in altitude. However, while parturitions were more synchronized with increasing altitude, we did not detect any trend along the latitudinal gradient. Finally, plant phenology explained altitudinal variation in parturition timing better than a linear effect of altitude. Our findings clearly demonstrate the ability of a large herbivore to match parturition timing with phenological conditions across the altitudinal gradient, even at the smallest spatial scales.

Habitat use of prey species is often subjected to strong trade-offs when foraging needs and predator avoidance cannot be met simultaneously. Trade-offs may be particularly pronounced for species dwelling above ground throughout the year. Identifying habitat use of such species may help to determine crucial and limited environmental resources and has strong implications for habitat management. We investigated the relative importance of habitat structure and composition for mountain hares in the Swiss Alps at the small scale for two time periods, throughout the year and during the reproductive period. Habitat use was assessed by a non-invasive approach that considers the spatio-temporal distribution of fecal pellets, sampled along systematically distributed transects. We found that heterogeneous habitats with high diversity of vegetation layers and/or abundance of saplings and storeyed vegetation structures are strongly used. The availability of shelter was more important in summer when hares strongly used dense habitats that offered protection from predators. The availability of food was more important as predictor for year-round use compared to the reproductive period when food is overabundant for hares. A heterogeneous habitat provides an optimal distribution and availability of shelter and food resources and allows the hare to adjust its activity pattern to changing environmental conditions. Therefore, the occurrence of a structurally heterogeneous ecotone at the upper timber line with a mosaic of different vegetation types and hiding structures should be considered in the management of the species.

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Measurement of glucocorticoid metabolites (GCM) in faeces has become a widely used and effective tool for evaluating the amount of stress experienced by animals. However, the potential sampling bias resulting from an oversampling of individuals when collecting “anonymous” (unknown sex or individual) faeces has rarely been investigated. We used non-invasive genetic sampling (NIGS) to investigate potential interpretation errors of GCM measurements in a free-living population of mountain hares during the mating and post-reproductive periods. Genetic data improved the interpretation of results of faecal GCM measurements. In general GCM concentrations were influenced by season. However, genetic information revealed that it was sex-dependent. Within the mating period, females had higher GCM levels than males, but individual differences were more expressed in males. In the post-reproductive period, GCM concentrations were neither influenced by sex nor individual. We also identified potential pitfalls in the interpretation of anonymous faecal samples by individual differences in GCM concentrations and resampling rates. Our study showed that sex- and individual-dependent GCM levels led to a misinterpretation of GCM values when collecting “anonymous” faeces. To accurately evaluate the amount of stress experienced by free-living animals using faecal GCM measurements, we recommend documenting individuals and their sex of the sampled population. In stress-sensitive and elusive species, such documentation can be achieved by using NIGS and for diurnal animals with sexual and individual variation in appearance or marked individuals, it can be provided by a detailed field protocol.