Wildlife-vehicle collisions (WVC) strongly impact road safety. While technical aspects of collision risk and the effects of roads on animal populations are well studied, knowledge about wildlife behaviour prior to and during contact with oncoming vehicles as a crucial aspect of collision risk is still lacking. We analysed 28,400 hours of video data (thermal network cameras at 14 road sections in south-west Germany) with 2,841 animal-vehicle encounters (1,960 roe deer, Capreolus capreolus, 696 red fox, Vulpes vulpes and 185 wild boar, Sus scrofa) and classified animal behaviour before and during contact with a vehicle. We fitted two sets of models to the data. In the first step, we modelled the intensity of the behavioural reaction exhibited by the animals as a function of behavioural and environmental predictors using ordinal Bayesian mixed-effect regression models. In a second step, we modelled the probability of a positive vs. a negative behavioural response in terms of WVC risk using binomial mixed-effect regression models. Both the intensity of behavioural reactions as well as the degree of risk during the interaction with oncoming vehicles differed among the species and as a function of road section layout. Our results showed that animal attentiveness, the behaviour a priori, access to cover, vehicle type and biological seasonality were important predictors of an animal's response to oncoming vehicles. More specifically, roe deer reacted to oncoming vehicles mostly with short movements away from the road, foxes often reacted unpredictably and wild boar behaviour appeared to be least affected by oncoming vehicles. Thus, we suggest that collision risk for common European mammals is shaped by the interplay of vehicle type, the road layout as well as the species-specific behavioural repertoire including the attentiveness of the animal and the behavioural state prior to an approaching vehicle. In addition, wildlife warning reflectors, a frequently used technique in WVC mitigation, did not alter behavioural reactions and thus failed to reduce WVC risk.

Climate change and associated changes in weather patterns have globally widespread effects on natural systems. Shifts in phenology can affect the reproductive success of birds by causing a mismatch between the onset of breeding and favourable conditions for reproduction, such as a peak in food availability. Weather conditions and their changes have also long been discussed as affecting the reproductive success of grouse (Tetraoninae) and contributing to rapid declines in many central European populations. We monitored the reproductive success of Western Capercaillie Tetrao urogallus in the Black Forest, Germany, over a 14‐year period to study how weather conditions correlated to reproductive success and to assess whether changing environmental conditions were related to a seasonal shift in reproduction. We observed a temporal shift in peak lekking activity from late to mid‐April, which corresponds to an advance of 0.65 days/year. Furthermore, we show that warm conditions during the reproductive season were positively associated with reproductive success (i.e. larger brood size, more hens with chicks and more chicks per hen) and that precipitation volume during the early weeks after hatching was negatively correlated with brood size. Precipitation before copulation (i.e. peak of lekking) affected the proportion of hens with chicks and the number of chicks per hen. Sex ratio in broods was also affected by weather conditions, with more female than male chicks in years with low temperatures and high precipitation. By analysing spring weather predictions for the period 2020–2039, we found that weather conditions during the reproductive period remained constant when assuming a continued advancement of reproduction onset, although annual variation was high. We show the importance of weather conditions in influencing Western Capercaillie reproductive success. Western Capercaillie in the Black Forest seem to adjust the timing of reproduction according to changes in weather conditions, but this advancement is unlikely to be limitless, making the future impact of climate change on the species uncertain.

• Key message The browsing level of oak (Quercus petraea and Quercus robur) and fir (Abies alba) provided only a rough estimate of the expected regeneration success. Thus, it cannot be recommended as a standard measurement to predict forest development, unless the number of saplings and the height of those saplings are considered. • Context Browsing by large herbivores may affect regeneration success and forest development, with an impact that lasts for decades. • Aims Whether the browsing level of a tree species can be used in forestry as a standard measure to assess whether the target values (for instance regeneration success) of highly selected tree species, such as oak ( Quercus petraea (Mattuschka) Liebl., Quercus robur ( L. )) and fir ( Abies alba (Mill. )), will be reached is unclear and need specification. • Methods In this study, 985 sampling plots (10 m 2 ) in Southern Germany (Baden-Württemberg) containing browsed and unbrowsed oak and fir-saplings were analysed. Both the browsing level and a measure of the expected regeneration success that considered not only the sapling density but also different height classes (≤ 20 cm; 21–50 cm; 51–130 cm) were calculated. • Results The use of the browsing level as a proxy for the expected regeneration success was statistically only partly justified. For fir the relationship between browsing level and expected regeneration success became even weaker for a new indicator variable which considers two height classes rather than one class for saplings exceeding 50 cm (51–80 cm and 81–130 cm). • Conclusion According to these results, the browsing level cannot be recommended as a standard measurement and/or predictor of damage, unless the number of saplings and the height of those saplings are considered. Thus, in efforts to mitigate conflicts between foresters and hunters, a measurement is needed that addresses the successful establishment of a sufficient number of trees despite browsing, rather than the browsing of trees alone.

The recent increase in wind energy facilities (WEF) has led to concerns about their effect on wildlife. While the focus of most studies has mainly been on increased mortality of birds and bats due to collision, indirect effects, such as behavioural responses, are currently gaining attention. Indeed, effects of WEF on the behaviour of forest dwelling wildlife still remain largely unknown. Using GPS-tracking of 16 individuals, we studied how seasonal resource selection of the capercaillie Tetrao urogallus, a forest grouse species known as sensitive to disturbance by human presence and infrastructure, was related to wind turbines and other environmental covariates in a wind farm in Sweden. During the lekking season, the probability of site-selection by capercaillie decreased with increasing turbine noise, turbine visibility and turbine shadow. During summer, we found reduced resource selection with increasing proximity to the turbines (up to 865 m), turbine density, noise, shadow and visibility. Furthermore, we found an avoidance of turbine access roads. Due to the high collinearity of the wind turbine predictors it was not possible to identify the specific mechanism causing turbine avoidance. Our study reveals that forest dwelling species with known sensitivity to other forms of human disturbance (i.e. recreation) are also likely to be affected by wind turbine presence. In addition, we provide proximity thresholds below which effects are likely to be present as a basis for conservation planning.

Capsule Open forest stands with high levels of sunlight and Bilberry Vaccinium myrtillus cover are important for Capercaillie Tetrao urogallus broods. Aims To study the habitat use by Capercaillie broods in the Black Forest, Germany. Methods Habitat characteristics were mapped at locations where indirect signs and observations of Capercaillie broods were recorded along transects. These were compared to habitat characteristics at random locations along the transects using generalized linear mixed models. Results Capercaillie broods in the Black Forest preferred open forest stands with canopy gaps, long daily sun exposure on the ground and an intermediate cover of Bilberry. Stands with high levels of ground vegetation cover and Mountain Pine Pinus mugo shrubs were preferred by Capercaillie broods, while stands with high levels of regeneration cover were avoided. No effect of the horizontal stand layers, number of basal-branched solitary trees or anthills was found. Conclusions To improve habitats for Capercaillie broods, we advise that there should be active creation of structured open stands and forest gaps in areas with high levels of sun exposure (south-west facing) and where Bilberry or heather dominates the ground vegetation.

Abstract The contribution of spatial processes to the spatial patterns of ecological systems is widely recognized, but spatial patterns in the ecology of plant‐herbivore interactions have rarely been investigated quantitatively owing to limited budget and time associated with ecological research. Studies of the level of browsing on various tree species reported either no spatial auto‐correlation or a small effect size. Further, the effects of disturbance events, such as hurricanes, which create large forest openings on spatial patterns of herbivory are not well understood. In this study, we used forest inventory data obtained from the federal state of Baden‐Württemberg (Southern Germany) between 2001 and 2009 (grid size: 100 × 200 m) and thus, after hurricane Lothar struck Southern Germany in 1999. We investigated whether the browsing level of trees (height ≤ 130 cm) in one location is independent of that of the neighborhood. Our analyses of 1,758,622 saplings (187.632 sampling units) of oak (Quercus), fir (Abies), spruce (Picea), and beech (Fagus) revealed that the browsing level is characterized by a short distance spatial auto‐correlation. The application of indicator variables based on browsed saplings should account for the spatial pattern as the latter may affect the results and therefore also the conclusions of the analysis.

There are growing concerns about the effects of wind turbines on wildlife. Additional mortality due to collisions with wind turbines has long been recognized as a direct negative effect, but less obvious effects such as changes in behaviour or displacement of disturbance sensitive wildlife are increasingly moving into focus. We combined systematic mapping of habitat structure and species presence before and after turbine-construction at 6 study areas in Germany, Austria and Sweden to study the effects of wind turbine presence on a large forest grouse species: the capercaillie (Tetrao urogallus). We studied effects of wind turbines on the observation density (percent of sampling plots with capercaillie presence per year and study area) and habitat selection. We did not find a significant difference in overall observation densities between turbine and control areas after turbine construction. At the sampling-plot scale, however, selection of habitats affected by wind turbines was reduced, indicating a form of habitat deterioration. This was detectable up to 650 m distance to the turbines, present across all study areas and independent of the structural habitat suitability at the respective site. Our results show that a disturbance-sensitive forest bird species is affected by wind energy development, and that critical-distances should be taken into account when planning wind energy development in grouse habitats.

There is increasing concern about the impact of the current boom in wind energy facilities (WEF) and associated infrastructure on wildlife. However, the direct and indirect effects of these facilities on the mortality, occurrence and behaviour of rare and threatened species are poorly understood. We conducted a literature review to examine the potential impacts of WEF on grouse species. We studied whether grouse (1) collide with wind turbines, (2) show behavioural responses in relation to wind turbine developments, and (3) if there are documented effects of WEF on their population sizes or dynamics. Our review is based on 35 sources, including peer-reviewed articles as well as grey literature. Effects of wind turbine facilities on grouse have been studied for eight species. Five grouse species have been found to collide with wind turbines, in particular with the towers. Fifteen studies reported behavioural responses in relation to wind turbine facilities in grouse (seven species), including spatial avoidance, displacement of lekking or nesting sites, or the time invested in breeding vs. non-breeding behaviour. Grouse were affected at up to distances of 500 m by WEF infrastructure, with indications of effects also at bigger distances. In six cases, a local reduction in grouse abundance was reported in areas with wind turbines, which possibly affected population size. Due to the differences in study duration and design, we cannot provide general conclusions on the effects of WEF on grouse populations. We advise applying the precautionary principle by keeping grouse habitats free of wind energy developments, in particular where populations are small or locally threatened. Future studies should preferably apply a long-term before-after-control-impact design for multiple areas to allow for more general conclusions to be drawn on the effects of WEF on rare and threatened wildlife species.

Outdoor recreation activities are growing in popularity, causing increasing pressure on wildlife. There are various ways in which wildlife reacts to recreation activities, ranging from behavioural to physiological responses, with regional variation in response-intensity within the same species. We tested whether the effects of human recreation are modulated by overall structural habitat suitability, using a model that included vegetation and topography, at both the regional and local habitat use scale. By undertaking a systematic, plot-based survey over 13 years in 13 study regions across central Europe, we studied how recreation infrastructure and habitat suitability interact and affect the variation in regional densities and local habitat use of an endangered model species: the western capercaillie (Tetrao urogallus). Both regional densities and local habitat use varied greatly between study years and regions. Capercaillie densities were positively correlated with average habitat suitability, but significantly reduced when over 50% of the area was influenced by recreation activities. Habitat suitability was the main predictor determining local habitat use. Recreation infrastructures were avoided: the effect being stronger in poor habitat conditions, while slightly mediated by high habitat suitability. Our results indicate that effects of recreation activities might be mitigated by improving habitat suitability; however this has limits because it only affects local scale habitat use but not regional densities. We stress the importance of recreation-free areas which must cover extensive (i.e. > 50%) parts of the species range.

t homerange selection, strong effects on habitat use within the homerange were detected: Distance to recreation infrastructure (hiking and cross-country skiing trails, ski pistes) was the main determinant of habitat selection in winter; in summer, mountain bike trails and hiker's restaurants were avoided up to an average distance of 145m (CI: 60-1092m). Around winter-infrastructure, relative avoidance was recorded up to 320m (CI: 36-327m), it was reduced, however, when dense understory provided visual cover. Of the entire population area, between 8-20% (summer) and 8-40% (winter) were affected by outdoor recreation, mainly in the high altitudes. Even without evident large-scale shifts in species distribution, local-scale avoidance of outdoor recreation can substantially contribute to effective habitat reduction. Based on our results we recommend a general reduction in recreation infrastructure density in key habitats, the establishment of undisturbed wildlife refuges with a diameter of at least 800m, as well as enhancing visual protection by maintaining a strip of dense understory along trails.

Numerous studies have addressed the question of whether hunting is capable of limiting the abundance of ungulates in the northern hemisphere. We investigated whether the hunting of red deer ( Cervus elaphus ) has reduced their abundance in the Southern Black Forest (area 17,500 ha), Southern Germany, since 2006. Red deer abundance was estimated using data obtained from visual counts at winter feeding sites, track counts, and bag records. An age- and sex-structured population model to estimate the winter population size was also constructed using bag records. The estimated red deer population size was evaluated according to a non-invasive genetic mark-recapture approach. The results showed that the hunting of red deer can reduce their population size if the hunting regime is part of a holistic management concept that takes into account the uncertainty of population size estimates and is implemented at scales appropriate to the management of this species.

Mammalian generalist mesopredators can reach high densities in forest-farmland mosaic landscapes in the absence of top-down control. The abundance of generalist mesopredators is a potentially limiting factor for prey populations, especially ground breeding birds such as grouse. High mesopredator abundance has been associated with reduced reproductive success in grouse. There is little evidence, however, on how variation in mesopredator abundance affects grouse population trends while considering other environmental covariates. We make use of range maps spanning two decades (1993-2013) of a locally threatened capercaillie (Tetrao urogallus) population in the Black Forest, Germany, to assess whether range loss of grouse in forest-farmland mosaic landscapes can be explained by a gradient in red fox abundance, while accounting for other potential determinants of grouse range loss. We show that capercaillie range persistence was favored by increasing snow cover, decreasing index of red fox abundance, slightly increasing index for soil quality, and increasing population connectivity. Red fox abundance had the largest relative impact in areas already facing an elevated capercaillie extinction risk due to unsuitable site conditions, dense forests, or lack of connectivity, but the negative effect was compensated under otherwise optimal conditions. This indicates that the relative importance of predator abundance for prey population dynamics is mediated by environmental attributes, emphasizing the threat to remnant populations but also indicating potential for species conservation.

Outdoor recreation inflicts a wide array of impacts on individual animals, many of them reflected in the avoidance of disturbed areas. The scale and spatial extent, however, at which wildlife populations are affected, are mostly unclear. Particularly in geographically isolated populations, where restricted habitat availability may preclude a relocation to undisturbed areas, effective habitat reduction may remain underestimated or even unnoticed, when animals stay in disturbed areas and only show small‐scale responses. Based on telemetry data, we investigated the spatial and seasonal effects of outdoor recreation – in relation to landscape and vegetation conditions – on western capercaillie Tetrao urogallus, considering two scales, home range and within‐home range habitat selection. We determined the distance‐thresholds up to which recreation infrastructures were avoided and estimated the extent of affected habitat for the isolated Black Forest (southwestern Germany) study population. While outdoor recreation did not affect home range selection, strong effects on habitat use within the home range were detected: distance to recreation infrastructure (hiking and cross‐country skiing trails, ski pistes) was the main determinant of habitat selection in winter; in summer, mountain bike trails and hiker's restaurants were avoided up to an average distance of 145 m (CI: 60–1092 m). Around winter‐infrastructure, relative avoidance was recorded up to 320 m (CI: 36–327 m), it was reduced, however, when dense understory provided visual cover. Of the entire population area, between 8–20% (summer) and 8–40% (winter) were affected by outdoor recreation, mainly in the high altitudes. Even without evident large‐scale shifts in species distribution, local‐scale avoidance of outdoor recreation can substantially contribute to effective habitat reduction. Based on our results we recommend a general reduction in recreation infrastructure density in key habitats, the establishment of undisturbed wildlife refuges with a diameter of at least 800 m, as well as enhancing visual protection by maintaining a strip of dense understory along trails.

Millions of animals are killed by vehicle collisions each year. As mitigation measures, wildlife warning reflectors have become increasingly popular, although clear evidence for their effectiveness is lacking. A reason for inconclusive results in the literature may be that most previous studies on the effectiveness of wildlife warning reflectors compare animal-vehicle collision rates with and without reflectors, a setting characterised by low event rates and weak experimental control. Animal behaviour can be expected to provide a more direct evidence for a possible effect of reflectors. In this study, we analyse roe deer behaviour in the presence of a blue semicircle reflector, one of the most frequently applied wildlife warning reflectors in Germany and other parts of Europe. Behavioural response to these reflectors (classified as no reaction, vigilance, short-distance flight and long-distance flight) was recorded both under controlled experimental conditions with captive roe deer and for free-ranging roe deer at road sections with traffic occurrence. We used generalised linear mixed models (GLMMs) to test if reflector presence induced threat-related behaviour (vigilance, flight) and movement away from the reflectors. We found no significant evidence that the light stimulus emitted by reflectors was perceived as a threat or induced evasive movement. We conclude that our study provides no evidence that blue semicircle reflectors induce behaviour in roe deer that seems suitable to reduce roe deer-vehicle collisions.

The rapid spread and diversification of outdoor recreation can impact on wildlife in various ways, often leading to the avoidance of disturbed habitats. To mitigate human-wildlife conflicts, spatial zonation schemes can be implemented to separate human activities from key wildlife habitats, e.g., by designating undisturbed wildlife refuges or areas with some level of restriction to human recreation and land use. However, mitigation practice rarely considers temporal differences in human-wildlife interactions. We used GPS telemetry data from 15 red deer to study the seasonal (winter vs. summer) and diurnal (day vs. night) variation in recreation effects on habitat use in a study region in south-western Germany where a spatial zonation scheme has been established. Our study aimed to determine if recreation infrastructure and spatial zonation affected red deer habitat use and whether these effects varied daily or seasonally. Recreation infrastructure did not affect home range selection in the study area, but strongly determined habitat use within the home range. The spatial zonation scheme was reflected in both of these two levels of habitat selection, with refuges and core areas being more frequently used than the border zones. Habitat use differed significantly between day and night in both seasons. Both summer and winter recreation trails, and nearby foraging habitats, were avoided during day, whereas a positive association was found during night. We conclude that human recreation has an effect on red deer habitat use, and when designing mitigation measures daily and seasonal variation in human-wildlife interactions should be taken into account. We advocate using spatial zonation in conjunction with temporal restrictions (i.e., banning nocturnal recreation activities) and the creation of suitable foraging habitats away from recreation trails.

Every year, there are millions of documented vehicle collisions involving cervids across Europe and North America. While temporal patterns in collision occurrence are relatively well described, few studies have targeted deer behaviour as a critical component of collision prevention. In this study, we investigated weekly and daily patterns in road crossing behaviour in roe deer. Using road crossing events and movement data obtained from GPS telemetry, we employed mixed-effect models to explain frequency and timing of crossings at five road segments by a number of predictors including traffic volume, deer movement activity and the presence of wildlife warning reflectors. We analysed 13,689 road crossing events by 32 study animals. Individual variation in crossing frequency was high but daily patterns in crossing events were highly consistent among animals. Variation in the intensity of movement activity on a daily and seasonal scale was the main driver of road crossing behaviour. The seasonal variation in crossing frequency reflected differences in movement activity throughout the reproductive cycle, while daily variation in the probability to cross exhibited a clear nocturnal emphasis and reflected crepuscular activity peaks. The frequency of road crossings increased as a function of road density in the home-range, while traffic volume only exerted marginal effects. Movement activity of roe deer in our study coincided with commuter traffic mainly in the early morning and late afternoon during winter and during periods of high spatial activity such as the rut. Both timing and frequency of crossing events remained unchanged in the presence of reflectors. Our results emphasise the importance of behavioural studies for understanding roe deer vehicle-collision patterns and thus provide important information for collision prevention. We suggest that mitigation of collision risk should focus on strategic seasonal measures and animal warning systems targeting drivers.

Even though Capercaillie are still present in large parts of its original range, its numbers have decreased in many parts of the Western and Central European range and in several cases, local populations have gone extinct. The Capercaillie population in the Black Forest, South-Western Germany, has undergone drastic declines in the past decades. In 1971 the number of male Capercaillie displaying at lekking sites throughout the Black Forest was counted for the first time, and since 1983 counts have been performed on a yearly basis. From 1993 onwards, all sightings and signs of Capercaillie presence have been documented and combined to create a distribution map, which is updated every five years. The lek-counts show fluctuations in the number of displaying males, but with a strong decline becoming evident over the entire study period: whereas roughly 450 males were counted between 1983 and 1994, the last count in 2016 revealed only 206 males. The decline was paralleled by a decline in range from 607 km2 in 1993 to 457 km2 in 2013. This 25 % decline is not evenly distributed in the Black Forest but is largest in the Southern and Eastern Black Forest («Sud-Schwarzwald» and «Baar-Schwarzwald») compared to the subpopulations in the Northern and Central parts of the study area. Possible causes include: habitat loss and deterioration, climate change, anthropogenic disturbance and increasing numbers of predators, most likely several of these operating in conjunction.

The precautionary principle is an essential guideline in decision making, particularly for regulating novel developments with unknown or insufficiently proven environmental impact. However, due to the inherent component of uncertainty it has been widely criticized for being “unscientific”, i.e. hindering progress without sufficient evidence. The consequential postulation, that precautionary measures are only justified if the addressed threats are plausible and the measures reasonable, calls for methods to guide action in the face of uncertainty. Using the example of species conservation versus wind-farm construction, an expanding development with hypothesized – but unexplored – effects on our model species the capercaillie (Tetrao urogallus), we present an approach that aims at compensating the lack of knowledge about the threat itself by making best use of the available knowledge about the object at risk. By systematically combining information drawn from population monitoring and spatial modelling with population ecological thresholds, we identified areas of different functionality and importance to metapopulation persistence and connectivity. We integrated this information into a spatial concept defining four area-categories with different implications for wind power development. Highest priority was assigned to areas covering the spatial and functional requirements of a minimum viable population, i.e. sites where the plausibility for threat is highest, the uncertainty as regards importance for the population is lowest, and thus the justification for precautionary measures is strongest. This gradated approach may also enhance public acceptance, as it attempts to avoid either error-minimization bias (i.e. being too restrictive or permissive) the precautionary principle is frequently criticized for.

Species adapted to cold-climatic mountain environments are expected to face a high risk of range contractions, if not local extinctions under climate change. Yet, the populations of many endothermic species may not be primarily affected by physiological constraints, but indirectly by climate-induced changes of habitat characteristics. In mountain forests, where vertebrate species largely depend on vegetation composition and structure, deteriorating habitat suitability may thus be mitigated or even compensated by habitat management aiming at compositional and structural enhancement. We tested this possibility using four cold-adapted bird species with complementary habitat requirements as model organisms. Based on species data and environmental information collected in 300 1-km2 grid cells distributed across four mountain ranges in central Europe, we investigated (1) how species' occurrence is explained by climate, landscape, and vegetation, (2) to what extent climate change and climate-induced vegetation changes will affect habitat suitability, and (3) whether these changes could be compensated by adaptive habitat management. Species presence was modelled as a function of climate, landscape and vegetation variables under current climate; moreover, vegetation-climate relationships were assessed. The models were extrapolated to the climatic conditions of 2050, assuming the moderate IPCC-scenario A1B, and changes in species' occurrence probability were quantified. Finally, we assessed the maximum increase in occurrence probability that could be achieved by modifying one or multiple vegetation variables under altered climate conditions. Climate variables contributed significantly to explaining species occurrence, and expected climatic changes, as well as climate-induced vegetation trends, decreased the occurrence probability of all four species, particularly at the low-altitudinal margins of their distribution. These effects could be partly compensated by modifying single vegetation factors, but full compensation would only be achieved if several factors were changed in concert. The results illustrate the possibilities and limitations of adaptive species conservation management under climate change.