Annika M. Felton

Managing and conserving species in the face of the current biodiversity crisis requires consistent information on the status of wild animal populations across large spatiotemporal scales. Budgetary constraints, differences in national legislation, and the challenges of coordinating logistics transnationally often limit survey efforts to spatial extents that rarely encompass the full distribution of many species, and temporal extents that rarely exceed a few years. These limitations are particularly relevant in regions like Europe, where multiple countries often share and manage populations of the same wild species across national borders and under different legislative frameworks. Cooperation and collaboration can help overcome some of these challenges. Here, we present data from the first 2 years of Snapshot Europe, a collaborative, coordinated, and standardized European‐wide mammal survey conducted by camera‐trap experts working across the continent. Between mid‐August and mid‐November of 2021 and 2022, more than 160 researchers simultaneously collected camera‐trap data at 1198 and 967 locations across 81 and 55 arrays and 22 and 23 countries, respectively, for a total of 90,230 camera‐trap days (49,033 and 41,197 in 2021 and 2022, respectively), with 91% of the data collected in September and October. Thirty (28%) out of 106 arrays across the 2 years were sampled both in 2021 and 2022, allowing for comparisons of estimates over time. All data were managed and processed in Wildlife Insights ( https://www.wildlifeinsights.org/ ); each record was reviewed by at least one participant who confirmed or edited the initial classifications provided by the AI model integrated into the platform. The final dataset contains a total of 94,441 observations of 63 species of mammals and 5024 detections of 78 species of birds. These data capture a subsample of the European wildlife community and can be used to explore ecological questions related to drivers of distribution, abundance, and activity across the continent. We envision repeating this effort annually for the foreseeable future. Data for Snapshot Europe 2023, 2024, and 2025 are currently being revised and will be made publicly available soon. Collated, all the annual datasets will enable estimates of trends over time. Additionally, four sister initiatives, Snapshot USA (2019‐ongoing), Snapshot Japan (2023‐ongoing), Snapshot Brazil and Snapshot Chile (both started in 2025), annually collect data based on the same sampling protocol, enabling a new era of global‐scale comparisons. The images associated with the data accompanying this publication are available in Wildlife Insights. The data are available for reuse under CC BY‐SA 4.0 licensing. Please cite this data paper when reusing all or part of this dataset.

Evidence‐based forest and wildlife management requires precise estimates of forage availability for spatial planning and conflict mitigation. Recently, novel datasets and associated maps have been developed for use in Swedish forest and wildlife management. These foodscape maps show the estimated nationwide abundance of six tree species, within a browsing height window, that are important forage sources for Swedish ungulates. In this short communication, we tested their applicability to infer on movement and habitat selection using GPS data of 54 adult moose in two study sites in southern and central Sweden. We model habitat selection using a combination of a three‐state hidden Markov model (HMM) and integrated Step Selection Analysis. We further tested their performance in models where habitat selection was not accounted for ( behavior‐unspecific models). Models containing information on both the foodscape and landcover performed best in the foraging HMM state and in behavior‐unspecific models, across all seasons. In the encamped and travelling HMM state, forage + landcover models performed similarly to forage models. In behavioral states associated with foraging, habitat selection models containing data from the foodscape maps were consistently selected as the most parsimonious models compared to models that only included landcover information as covariates. Further, moose showed nuanced habitat selection patterns based on their behavioral state, and selection for young forest shifted once forage abundance was accounted for, from a generally preferred habitat to a generally avoided habitat. We showcase the predictive capability of the newly developed maps to draw nuanced inference on habitat selection of moose across several seasons in several behavioral states.

Bark beetle outbreaks are an increasingly important disturbance in boreal forests, yet empirical evidence is limited on how management systems influence stand- and tree-level susceptibility. We quantified infestation patterns of Ips typographus, Pityogenes chalcographus, and Polygraphus spp. across 29 spruce-dominated forest stands in central Sweden representing mature even-aged, uneven-aged, and unmanaged forests. Using GLMs and GLMMs, we evaluated how management type, stand structure, and tree characteristics influenced stand-level infestation intensity and tree-level infestation probability. Stand-level infestation patterns were driven primarily by structural variables rather than management type. Deadwood basal area was the strongest and most consistent predictor for all species, positively associated with infestation intensity. For P. chalcographus, negative associations with spruce density and pine basal area highlighted species-specific responses to stand composition. At the tree level, both I. typographus and P. chalcographus showed higher infestation probability in even-aged stands, independent of diameter, sun exposure, and tree condition. Ips typographus preferentially colonized larger and more sun-exposed trees, whereas P. chalcographus favoured smaller trees. Polygraphus spp. showed no detectable response to tree size or sun-exposure but favoured standing trees. Our results show that forest susceptibility to primary bark beetles is shaped more by structural attributes than by management type alone. However, even-aged management increased infestation risk at the tree-level, suggesting that management can affect tree-level susceptibility without necessarily increasing stand-level infestation. These findings highlight that susceptibility to bark beetles cannot be inferred from management system alone but depends on the specific habitat conditions present within the stands.

Moose Alces alces is a culturally and economically important game species in Sweden, but their browsing on regenerating Scots pine trees Pinus sylvestris often causes extensive damage to the production and quality of timber. Forest and wildlife managers are faced with the dilemma of how to reduce damage to timber trees while also supporting moose populations and hunting opportunities. The proportion of damaged trees can be reduced by decreasing the number of moose, but also by increasing the number of pines. However, the relative effectiveness of these two approaches is debated and has not been conclusively determined. Here, we addressed this question by analyzing the effects of moose and pine density on pine damage based on yearly data from almost all of Sweden's moose management areas (MMAs) over a 10‐year period (2015–2024; 718 observations). We developed a mechanistic model to realistically represent the browsing process and used regression with mixed models to account for variable vulnerability (variation in damage risk at a fixed moose per pine ratio) among MMAs in the statistical analysis. The model explained 53% of the variation in the proportion of damaged trees and showed that, on average, the relative damage reduction effect of a decreased moose population was ~ 1.5× larger (25%) than the effect of increased pine density (17%). Vulnerability to browsing varied substantially among MMAs and between years within each MMA, especially in areas with low pine density. This variability prevents reliable predictions of management effects at the individual MMA level for most MMAs. Such local predictions may be improved in the future by incorporating longer time series of observations and additional variables, such as alternative forage sources, browsing by other deer species, and snow cover and duration.

Shrubs of the genus Vaccinium serve as foundation species in boreal ecosystems as they define much of the structure of the ground vegetation and play key roles in many ecosystem services and processes. For example, Vaccinium myrtillus (bilberry) and Vaccinium vitis‐idaea (cowberry) constitute staple foods for several species of large herbivores (Cervidae, deer) in Northern Europe. However, changes to the tree layer from forestry practices have resulted in declines in habitat suitability and the abundance of these shrubs over recent decades. Here, we assess whether related changes to tree basal area and species composition also affect the macronutrient composition of these shrubs, and if so, how such alterations may influence food selection by moose ( Alces alces ). We sampled bilberry and cowberry twigs during wintertime in five study areas dispersed latitudinally in Sweden, using 65 forest stands dominated by Scots pine ( Pinus sylvestris ) or Norway spruce ( Picea abies ) that varied in age and site fertility, while also taking into account soil C:N, pH, and moisture. We found that the macronutrient composition of bilberry and cowberry forage was significantly altered by forest density and tree species composition. In denser and more spruce‐dominated forests (i.e., lower understory light), forage contained less nonstructural carbohydrates, but more protein and lignin, compared to shrubs growing in more open and pine‐dominated forests. We also found that the forage available in such shaded environments was closer to the presumed nutritional target balance of moose. Our results illustrate that management decisions influence the macronutrient composition of understory shrubs in a way that may be important for herbivore foraging choices. We suggest that a larger variation in forest structure, both within and among stands across the landscape, will provide cervids with greater variation in forage qualities, since even small differences in forest structure can increase the nutritional variation of the forage. We discuss our results in the context of plant resource allocation, herbivore nutritional balancing and game and forest management.

Cervid (Cervidae) populations that are overabundant with respect to their food resources are expected to show declining physiological and reproductive fitness. A proactive solution to such declines is to integrate the monitoring of food resources with animal harvesting strategies, but there are few studies available to guide managers regarding which food resources to monitor and how to do so. In this study, we used a large, rare data set that included detailed absolute measures of available food quantities and browsing intensity from field inventories, to test their relationship with fitness indices of moose Alces alces in 24 management units in four regions across Norway. We found that calf body mass and calves seen per cow during the autumn hunt were strongly and positively related to the availability of tree forage, especially the species most selected for by the study moose (e.g., rowan [ Sorbus aucuparia ] and sallow [ Salix caprea ]). The strength of the correlations varied between regions, apparently being stronger where the moose were closer to being overabundant or had a legacy of past overabundance. As expected, the intensity of browsing on the three most common tree species, that is, birch ( Betula spp.), rowan, and pine ( Pinus sylvestris ), was also negatively and strongly related to the fitness. We discuss how our approach to food monitoring can facilitate a management that proactively adjusts densities of moose, and possibly other cervids, to trends in food availability and browsing intensity, thereby avoiding detrimental effects of overabundance.

Across the northern hemisphere, ungulates are expanding in range and abundance, forming novel communities in increasingly human‐modified landscapes. These shifts drive new interactions over available food resources, but patterns of resource use and partitioning in Europe's multi‐species systems remain poorly understood. This study examined seasonal diets and resource partitioning in diverse cervid communities (moose, roe deer, red deer, and fallow deer) across two Swedish landscapes (coastal‐boreal and boreo‐nemoral) differing in deer density and land use. Based on their foraging strategies, we expected (Hypothesis 1) diet richness and dietary niche width to be greater in intermediate feeders (red and fallow deer) than in browsers (moose and roe deer), (Hypothesis 2) trophic partitioning between browsers and intermediate feeders to be driven mainly by graminoid use, and (Hypothesis 3) intra‐ and interspecific overlap to vary with season, deer density, habitat diversity, and proportion of arable land. DNA metabarcoding of 2568 fecal samples showed that deer consumed plants from over 70 families, though diets were typically dominated by fewer than 10. Vaccinium shrubs were key forages year‐round, while birch and willow dominated during the growing season. Moose consumed large amounts of pine in spring and winter (> 50% in the boreo‐nemoral, 35%–40% in the coastal‐boreal landscape), with less during summer‐autumn (~15%). Forbs were important for smaller deer, especially in spring and summer‐autumn, and more heavily used in winter in the boreo‐nemoral landscape, likely due to supplementary feeding with human‐provided food like hay or silage. Spruce use was low overall (< 5%), with fallow deer showing the highest intake. Consistent with Hypothesis 1, diet richness and niche width increased from moose to fallow deer. In partial support of Hypothesis 2, principal coordinates analysis (PCoA) revealed that graminoids contributed to trophic partitioning, but the pattern was not a strict browser–intermediate feeder divide. Moose consistently separated from the smaller deer due to avoidance of graminoids and reliance on pine and juniper, while roe deer, although a browser, sometimes overlapped with red and fallow deer through greater use of graminoids. During winter in the coastal‐boreal landscape, wavy hairgrass ( Avenella flexuosa ) contributed to the significant separation between browsing roe deer and intermediate‐feeding red deer diets, consistent with Hypothesis 2. Diet overlap among smaller deer varied with season and landscape. Intraspecific overlap was the highest in moose and the lowest in fallow deer, declining during summer–autumn across species. Overlap was influenced by deer density, habitat diversity, and arable land, consistent with Hypothesis 3, but effects were species‐specific and explained only limited variation. Our results highlight the dietary plasticity of red and fallow deer, which may intensify resource competition with moose and roe deer in multi‐species systems, particularly where supplementary feeding is common. These insights support adaptive, multi‐species management of deer in northern ecosystems.

Moose (Alces alces) is a culturally and economically important game species in Sweden but its browsing on young pine trees in (Pinus sylvestris) cause extensive damage to forestry. Management is therefore posed with the dilemma of how to reduce damage to timber trees, while at the same time support robust moose populations. The proportion damaged trees can be reduced by decreasing the number of moose, but also by increasing the number of pines. However, it is not clear exactly how effective these measures are in general and how their impacts vary across Sweden. Here we analyzed the effects of moose- and pine density on pine damage using yearly data from almost all of Sweden’s moose management areas over the period 2015-2024 (718 observations). We developed a mechanistic model to realistically represent the browsing process and used regression with mixed models to account for variable vulnerability (damage at a given number of moose per pine tree) among MMAs in the statistical analysis. The model explained 53% of the variation in proportion damaged trees and showed that, on average, the relative damage reduction effect of a decreased moose population was larger (25%) than the effect of increased pine density (17%). Vulnerability to browsing varied substantially among MMAs and between years within each MMA, especially in areas with low pine density. This variability prevents reliable predictions of management effects at individual MMA level for most MMAs. Such local predictions may be improved in the future by incorporating longer time series of observations and additional variables, such as alternative food, browsing by other deer species, and snow cover.