IntroductionFrom fortified borders to decorative garden walls, fences form ubiquitous widespread networks that sprawl across the global terrestrial landscape. Fences and walls are one of the oldest tools used by people to manage other people and wildlife, e.g., by marking territorial boundaries, separating livestock from wild animals, or monitoring the movement of people through border controls. There is no reliable measure of extent of the global fence network, however it is estimated to be at least 10 times that of the global road network (Jakes et al. 2018), which is currently more than 64 million km (Dulac 2013), and expected to reach 90 million km by 2050 (Laurance et al. 2014). Despite the enormous extent of the fence network, fences are rarely subjected to Environmental Impact Assessments, and the ecological impacts of fencing are severely underestimated and understudied (Jakes et al. 2018, McInturff et al. 2020, Buton et al. 2024). The main purposes of a fence – to fragment, isolate and/or reduce interactions – often align with negative ecological impacts, while meeting the goals to protect livestock, prevent access of invasive species, and control the spread of diseases (Terborgh et al. 2001, Woodroffe et al. 2014, Jakes et al. 2018, Mysterud and Rolandsen 2019, McInturff et al. 2020). Fences and walls are erected through all landscapes, including those that are ecologically important and protected. One example that has received a lot of media and political attention, is the recently constructed border fence between Poland and Belarus which cuts through Białowieża Forest, the best preserved lowland temperate forest in Europe and transboundary World Heritage Site (Jaroszewicz et al. 2021). Such barriers have the goal to hinder the flow of people, and consequently also block the movement of wildlife and challenge landscape connectivity (Olson and van der Ree 2015, Linnell et al. 2016), which can trigger a cascade of direct and indirect ecological impacts (e.g. Nowak et al, submitted). Border fences are also used to control the spread of diseases, such as African Swine Fever (ASF). With the aim to reduce the movement of infected wild boar, and contain ASF, fences have been built along numerous country borders in Europe, e.g., the 70-km long ASF fence at the German-Danish border which runs directly through Natura 2000 areas (Eilenberg and Harrisson 2023, Klein et al. 2024). Similar border fences to control ASF exist at the German-Polish border, and are planned to be installed at the Norwegian-Swedish border. The fragmentation effect of border fences is clear and apparent, however the impacts caused by fences that are for example, along roads and railways, denote property borders, or enclose protected areas are often underestimated. Without proper research of the downstream or indirect impacts to non-target species and the functioning of ecosystems, negative impacts of fences will continue to be overlooked and unaccounted for. This special issue provides a collection of articles in which authors present different perspectives on fences and how we, as humans, use fences to communicate with the natural world and manage wildlife. Finally, the issue provides guidelines to improve fence design and implementation, and discusses research steps to move forward in the field.

Abstract Understanding how species survive at their poleward limits of distribution is of interest in species conservation, particularly in light of global warming and predictions of shifting distributions of both predators and prey species. How species adapt to high latitudes and to future climate changes will be impacted both by direct interactions with the environment, such as changing heat tolerances, but also indirectly through biotic interactions with prey and predators. The smooth snake (Coronella austriaca) in Norway provides an interesting case study of biotic interactions at range limits. The number of potential prey species of C. austriaca is lower in Norway than in southern latitudes. To investigate trophic adaptations at its poleward range limit we used metabar-coding sequencing to identify prey species in stomach samples of a museum collection of 17 preserved C. austriaca from Agder in Southern Norway. Eight prey species were detected, four reptiles and four mammals. Field vole (Microtus agrestis) and common shrew (Sorex araneus) were the most common prey species, while bank vole (Myodes glareolus) and wood mice (Apodemus sylvaticus) were eaten only by a few smooth snakes. A. fragilis was found in five samples and Z. vivipara in only three samples. DNA was also recovered from grass snake (Natrix natrix) in all but one sample, and DNA from European adder (Vipera berus) in one sample, indicating the role of ophiophagy. Visual analysis of 75 faeces from the Oslo region showed that A. fragilis was the most common prey species, followed by shrews. The main conclusion is that C. austriaca in Norway have a higher proportion of mammalian prey in their diet compared to populations in more southern latitudes.

Investigating resource selection patterns of declining species is critical to developing effective conservation strategies and mitigating negative population trends. We trapped and radio-collared northern bobwhite (Colinus virginianus) and recorded the location of each individual three times per week during the northern bobwhite breeding season (April – September) to infer resource selection by non-brooding adults. We defined 13 vegetation communities with varying fire histories and assessed their relative use via a distance-based logistic regression model within a Bayesian framework. We found reliable evidence that non-brooding northern bobwhite preferred supplemental feed lines, recently burned natural pine stands, one-year rough in shrub/scrub, and one-year rough in hardwood-pine stands. Conversely, we found they avoided one-year rough in natural pine stands, recently burned shrub/scrub, and recently burned hardwood-pine stands. Our data suggest that non-brooding bobwhite’s successional stage preference may vary between vegetation communities within the same study area and adds further evidence to the importance of fire and vegetation interspersion in bobwhite management. Results from our study may be applied to enhance habitat for non-brooding northern bobwhite and potentially increase adult survival, an important metric correlated with bobwhite population growth.

Trophic interactions are crucial for maintaining ecological balance. In cities, avian predation has been shown to be particularly relevant due to its effects on community structure, pest control, and nutrient cycling. As humanity relies upon ecosystem services for survival and 70% of the human population is projected to live in cities by 2050, understanding the effects of urbanization on avian predation is imperative. This study investigates the effects of urban microclimates, impacted by impervious surface and green/blue infrastructure, and human-induced disturbances, on avian predation in urban areas. Plasticine caterpillars were placed in Quercus robur trees to assess the avian predation rate. The analyses evaluated the impact of artificial lighting at night, human population density, noise pollution, vegetation, and water bodies on predation rates during two months in the city of Amsterdam. Results indicated a substantial increase in predation during the second month, likely caused by an increase in naïve fledglings or elevated ambient temperatures. Noise pollution consistently emerged as the most reliable predictor of predation, consistently leading to a reduction in predation rates, possibly due to avoidance behaviour. Other predictors exhibited substantial temporal and spatial variability. Artificial lighting at night increased predation in the first month, suggesting that insectivorous birds predate near illuminated areas. The diminished effect of artificial lighting in the second month may be attributed to the increased daylength. During the second month, all predictors negatively affected predation, supporting the increasing disturbance hypothesis. These findings underscore the complex relationship between urban factors and avian predation, highlighting the need for mitigation efforts in urban planning.

Many factors, including individual- and species-specific traits and resource requirements as well as landscape characteristics, influence second-order habitat selection and home range characteristics such as size, shape, stability, and overlap. By comparing home range characteristics across individuals, species, and landscapes, we can draw conclusions regarding whether and how different factors influence home range selection. Our objectives were to quantify home range characteristics of VHF- and GPS-collared coyotes and red foxes in southern Wisconsin, including home range size and shape, home range stability, and inter- and intraspecific overlap, and to review current literature on coyote and red fox home range characteristics for comparison and context. On average, urban coyotes had smaller, more circular home ranges with greater intraspecific overlap than rural coyotes; although, rural coyotes had greater home range stability. Similarly, urban red foxes had smaller, more circular home ranges with greater intraspecific overlap than urban coyotes, with no difference in stability between urban coyotes and red foxes. Our results corresponded with trends identified from literature review; however, we did find greater interspecific overlap between urban coyotes and red foxes than has been previously reported. Our results provide further evidence that intrinsic and extrinsic factors, such as body size, resource predictability and availability as well as the physical environment, influence home range selection of coyotes and red foxes.

Geese and swans are focal species in conservation and in management aimed at reducing crop damage. In the former disturbance should be minimized, and in the latter it is important to know how different species react to scaring activities. Previous research about trade-offs between predation risk and foraging in birds often use ‘Flight Initiation Distance’ (FID) as a proxy to compare fearfulness under different circumstances and among species. We studied variation in FID in geese and swans by species, flock size and composition, time of day, and body size (408 scaring trials on agricultural land in the winters 2018—2021). In single-species flocks mean FID decreased in the order: bean goose (171 m) > greylag goose (104 m) > whooper swan (102 m) > Canada goose (92 m) > barnacle goose (77 m). In line with predictions based on body mass, the lightest species (barnacle goose) was the least fearful, but contrary to prediction neither of the two heaviest species (whooper swan, Canada goose) was the most fearful. FID was negatively correlated with flock size in bean goose. Flock size and FID did not correlate in greylag, Canada, and barnacle geese. FID did not differ between morning and afternoon in the 4 species with a sample of >20 single-species trials. When in multi-species flocks, FID differed less among species, converging in the 108—138 m range. Accordingly, bean goose FID decreased significantly whereas it increased significantly in barnacle and greylag geese. Barnacle goose (protected from hunting by the EU bird directive) was less fearful than species with an open hunting season in the EU, implying that exposure to hunting affect species-specific FID. We show that the level of fearfulness varied among swan and goose species, making it necessary to adopt diverse strategies in conservation as well as crop protection.

not-yet-known not-yet-known not-yet-known unknown One of the most difficult challenges for wildlife managers is reliably estimating wildlife populations. Camera traps combined with spatial capture recapture (SCR) models are a popular tool for population estimation. They have limitations, however, including long data processing times. Drones with thermal imagery are an emerging tool for estimating wildlife populations, but how they compare to other methods remain poorly studied. We compared the use of camera traps and SCR models to drone surveys for estimating population densities of Sitka black-tailed deer (Odocoileus hemionus sitkensis) on Afognak Island, Alaska. We deployed 26 camera traps from 1 September until 6 October 2022 and individually identified males using antler characteristics, for the SCR model. At the same site we conducted three drone surveys between October and December 2022, obtained deer counts, and identified sex composition. The estimated density from the SCR model was 3.7 males ± 0.8 (SE) /km2, and 14.1 ± 3.1 adults/km2 of clear-cut forest. Results from the drone survey produced similar estimates with 2.1 ± 0.9 males/km2 and 13.4 ± 1.6 adults / km2. The similarity in estimates suggests that both methods converged on an accurate representation of the population in this habitat, but these methods diverge in levels of sampling effort, duration, and financial cost. Camera traps offer further insights on behavior and home-range size but require longer data processing times, can be subject to malfunctions, and are difficult to deploy and maintain in remote areas. Drones are subject to legal restrictions, have difficulty in closed canopy habitat and can be initially costly, but they provide results faster and require less data analysis. Camera traps and drones are useful for determining population dynamics but are subject to their limitations. Wildlife managers should make survey decisions based on their specific goals, habitat type, focal species ecology and financial limitations.

We compared times series for rock ptarmigan densities (20032019) derived from walked transects and road transects in Mosfellsheiði and Slétta in southwest and northeast Iceland, respectively. The walked transects were laid out according to a random rule, but the road transects were not. Data from both survey types were analysed according to the distance sampling methodology. The purpose was to compare results derived from the two survey types. Road transects are easier to conduct than walked transects, but they break a fundamental rule of distance sampling, namely random placement of transects. Our results show that road transects are more than five times faster to conduct than walked transects. There were no indications that ptarmigan avoided roads. Population indices were similar for the two survey methods in both study areas. Density estimates in Mosfellsheiði were identical for the two survey methods but not in Slétta, where density estimates for road transects were lower. The Slétta road transects were biased low because parts of the road transect intersected habitat that ptarmigan do not occupy. This bias can be remedied at least partially by considering non-habitats by applying multipliers in the distance analysis.

Capture and manipulation are an integral part of wildlife research and management. These practices, however, can affect animals either directly or indirectly, and studies should generally evaluate the consequences of captures to ensure animal welfare and reduce sampling bias. Here, we investigated the indirect, behavioural effects of live-capture on escape response to humans in Alpine marmot Marmota marmota within the Stelvio National Park (central Italian Alps) over three seasons (2021- 2023). We used flight initiation distance (FID) as a measure of escape response and tested it in relation to capture status using linear mixed modelling. Captures did not have any detectable effect on escape response, and FID was best explained by covariates such as starting distance, distance to nearest burrow, current behaviour during the observation and year of observation. It might be that, in marmots, escape response to humans is a rather inert behaviour, and as such, although we cannot rule out unmeasured effects, capture may not represent an excessively traumatic experience which could trigger immediate behavioural modification. In turn, capture is unlikely to compromise animal welfare or cause scientific bias in studies investigating escape response in this species, at least over the short term.

The Nelchina Basin, located west of Glenallen, AK provides important moose (Alces alces) habitat throughout the year. However, previous research in this area has shown that the moose populations appear to be nutritionally limited by the available forage. The Nelchina Basin was deemed an intensive management unit to increase moose populations through predator control efforts and prescribed fires to increase the amount of available forage, including the 2004 Alphabet Hills fire. We quantified the available digestible energy (DE) and digestible protein (DP) during the summer of 2018 and 2019, as well as the winter in between, and availability of forages for moose within the burn perimeter and the adjacent unburned forest during the summer of 2019. We found that total canopy cover of the primary forage species was lower in the burned areas than in the adjacent unburned forest habitats. DP concentration was not significantly different between forested and burned sites, and DE and DP content varied across the summer and winter sampling season. We also found a significant difference in DE and DP across the two sampling years. Although others have shown a positive effect of wildfire for herbivore populations, we found that some areas, including the Alphabet Hills area, may not be suitably adapted to benefit from the quick release of nutrients after fire and may not allocate more resources to biomass as previously expected. This project highlights the importance of research that quantifies both the availability of and the quantity of available food resources for herbivores.

Wildlife biology is an applied discipline, where research results are to varying degree incorporated to accepted knowledge However, several factors appear to increase the divide between research results, and knowledge and implementation. First, there is an exponential increase in number of published papers, in part driven by misguided reliance on publication record for assessing scientific competence. The shear number of publications risk diluting knowledge through salami-slicing or simply making it difficult to find relevant publications. This development could be problematic for the future of wildlife biology, and it has made complex statistical analysis of already available data more profitable than the ability to generate new data in robust field studies. Research results are conceptually different from knowledge and need to be evaluated in a post-publication process to become knowledge. Secondly, the formulation of research questions has become restricted by the way research is organised and funded. A shift from a focus on individual performance to research groups could encourage the development of more complex research questions that are better suited to advance the knowledge of wildlife biology. Funding agencies and research institutions need to think beyond current norm of a three year funding package. Thirdly, defining knowledge as the result of a post-publishing evaluating of research publications would facilitate knowledge transfer between researchers and practitioners. It is well established that a two-way transfer of knowledge and experience is beneficial to both researchers and practitioners but the low return on academic recognition for such efforts is currently simply too low, which positively discourages researchers from dividing limited resources into such activities. Only academic institutions and funding agencies together can make the significant changes needed as have begun in other disciplines. However, researchers also need to embrace existing and emerging initiatives such as Open Sceince, FAIRdata, CREDIT authorship to accelerate change.

Though agriculture has been linked to the decline in bird populations due to the associated changes in vegetation structure and composition, its potential to sustain birds has been explored over time. A sustainable agricultural landscape should be one that has the capacity to support bird species all year. To this end, we investigated the factors influencing pre- and post-harvest farm conditions on bird abundance, richness, and feeding guilds in three different crop fields in Jos-East and North, central Nigeria. We used line transects to survey birds and vegetation variables from 30 fields each of legumes, maize, and mixed (maize and soya bean) during the pre- and post-harvest periods in central Nigeria. We first compared the variation in bird species richness, abundance, and feeding guild abundance across the three field types over the two periods. We then modeled the effects of field conditions and vegetation parameters on feeding guild abundance, species abundance, and species richness as response variables. Our results revealed significant variations in bird species richness, abundance, and feeding guild abundance across field types. The omnivorous guild was significantly higher pre-harvest than post-harvest whereas insectivorous and granivorous were significantly higher in-field than at the edge. Bird species richness, abundance, and feeding guild abundance were significantly higher pre-harvest than post-harvest and in-field than at the edge. In addition, in-field tree density had a significant positive influence on bird abundance and species richness as well as feeding guild abundance. This study shows that pre- and post-harvest conditions of crop fields can moderate the number and richness of birds on farmlands while the retention of trees on farmlands contributes to higher bird assemblages.

Efficient wildlife management requires precise monitoring methods, e.g., to estimate population density, reproductive success, and survival. Here, we compared the efficiency of drone and ground approaches to detect and monitor GPS-collared female moose (Alces alces) and their calves. Moreover, we quantified how drone (n = 42) and ground (n = 41) approaches affected moose behavior and space use (n = 24 individuals). The average time used for drone approaches was 17 minutes compared to 97 minutes for ground approaches, with drone detection rate being higher (95% of adult female moose and 88% of moose calves) compared to ground approaches (78% of adult females and 82% of calves). Drone detection success increased at lower drone altitudes (50-70 m). Adult female moose left the site in 35% of drone approaches (with > 40% of those moose becoming disturbed once the drone hovered < 50 m above ground) compared to 56% of ground approaches. We failed to find short-term effects (3-h after approaches) of drone approaches on moose space use, but moose moved > 4-fold greater distances and used larger areas after ground approaches. Similarly, longer-term (24-h before and after approaches) space use did not differ between drone approaches compared to days without known disturbance, but moose moved comparatively greater distances during days of ground approaches. In conclusion, we could show that drone approaches were highly efficient to detect adult moose and their calves in the boreal forest, being faster and less disturbing than ground approaches, potentially making them a useful tool to monitor and study wildlife.

1. The severe decline of hazel dormice (Muscardinus avellanarius) is well documented and has led to increased legislative protection both in the UK and across Europe. Conservation measures for this species often include provision of nestboxes as a mitigation or enhancement technique after development projects. Previous research has offered some insights into how to select suitable general locations for nestboxes, but where to best place individual boxes to promote occupancy is less well understood. We hypothesised microhabitat variables related to proximity to food sources and nest building material will affect nestbox occupancy by dormice and should be considered when placing individual boxes within a selected site. 2. To assess individual nestbox occupancy by hazel dormice, 76 microhabitat variables were collected from 45 occupied and unused nestboxes in a deciduous woodland in Berkshire,UK. Variables were then used to predict probability of nestbox occupancy (observed from 2017 to 2021) using Random Regression models. 3. Results reveal nestboxes were more likely to be occupied by hazel dormice in sites with higher local cover and abundance of hazel trees (Corylus avellana), greater overall tree abundance but not fully closed canopies (best around 80-85%), more hawthorn (Crataegus monogyna) and honeysuckle (Lolium periclymenum), and when located further from footpaths. 4. Our results build on previous literature on habitat preferences of hazel dormice and importantly provide insight into relevant microhabitat variables that offer recommendations for where to place individual nestboxes to promote occupancy and facilitate recovery of hazel dormice.

Survival among juvenile ungulates is an important demographic trait affecting population dynamics. In many systems, juvenile ungulates experience mortality from large carnivores, hunter harvest and climate-related factors. These mortality sources often shift in importance both in space and time. While wolves (Canis lupus) predate on moose (Alces alces) throughout all seasons, brown bear (Ursus arctos) predation and human harvest happen primarily during early summer and fall, respectively. Hence, understanding how the mortality of juvenile moose is affected by predation, harvest and climate is crucial to adaptively managing populations and deciding sustainable harvest rates. We used data from 39 female moose in south-central Scandinavia to investigate the mortality of 77 calves in summer/fall and winter/spring, in relation to carnivore presence (defined as wolf presence and bear density), summer productivity, secondary road density, winter severity and migratory strategy (migratory versus resident) using logistic regressions. Summer mortality varied significantly between years but was not correlated to any of our covariates. In winter, calf mortality was higher with deeper snow in areas with wolves compared to areas without and increased more strongly with an increasing proportion of clearcuts/young forests in the presence of wolves compared to when wolves were absent. Lastly, increasing hunting risk was associated with higher calf mortality, and migratory females had higher calf mortality compared to stationary ones. Our study provides useful insight into mortality rates of moose calves coexisting with two large carnivores and with an intensive harvest pressure. Increasing our understanding of the mechanisms driving calf mortality both in summer and winter will become increasingly important if the populations of wolves and bears continue to expand and the moose population declines, and both summers and winters become warmer.

The human population is growing rapidly, increasing pressure on natural habitats. Suitable habitats for resident and migratory waterbirds are, therefore, more threatened. This study analyses how the presence of anthropogenic land cover (urban area and cropland) on multiple spatial scales affects the community composition of waterbirds along the Nile in Egypt. We analysed data collected during the international waterbird census, 2017-2018, combined with data from satellite images on land cover at a multi-spatial scale. The census covered 970 km, compromising 194 shoreline transects of 5 km along the River Nile, Egypt. The area includes a broad gradient of human disturbance, making this dataset ideal for assessing effects of anthropogenic land cover on waterbird community composition. We tested whether the waterbird community indices and guild composition were associated with urban area and cropland, and other land covers (e.g., grassland, wetland) at spatial scales of 100, 500, 1,000 and 5,000 m. We recorded over 96,000 waterbirds and show that landscape characteristics at larger spatial scales (5,000 m) explained more of the species and guilds’ presence than smaller scales. Species richness increased with increasing water surface area of the river within the transect and decreased with increasing urban area and cropland. Waders were negatively associated with urban area. Overall, the guilds’ composition was poorly predicted by anthropogenic land cover and other landscape compositions, probably because species within a guild do not react similarly to increasing human disturbance. The probability of observing red-listed species decreased with increasing urban area. With this study, we expand on the existing evidence by showing that species richness negatively correlates with anthropogenic pressure, and we highlight the importance of studying the responses of species rather than guilds. Our study shows the relevance of considering the landscape at larger scales while planning for conservation measures, especially in such human-dominated landscapes. https://doi.org/10.1002/wlb3.01178

Chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is a major driver of amphibian decline worldwide. The global presence of Bd is driven by a synergy of factors, such as climate, species life history, and amphibian host susceptibility. Here, using a Bayesian data-mining approach, we modelled the epidemiological landscape of Bd to evaluate how the infection varies across several spatial, ecological, and phylogenetic scales. We compiled global information on Bd occurrence, climate, species ranges, and phylogenetic diversity to infer the potential distribution and prevalence of Bd. By calculating the degree of co-distribution between Bd and our set of environmental and biological variables (e.g., climate and species), we identified which factors could potentially be related to Bd presence and prevalence using a geographic correlation metric, epsilon (ε). We fitted five ecological models based on: i) amphibian species identity, ii) phylogenetic species variability values for a given species assemblage, iii) temperature, iv) precipitation, and v) all variables together. Our results extend the findings of previous studies by identifying the epidemiological landscape features of the presence of Bd. This ecological modelling framework allowed us to generate explicit spatial predictions for Bd prevalence at global scale and a ranked list of species with high/low probability of Bd presence. Our geographic model was able to identify areas with high potential for Bd prevalence as potential risk areas and areas with low potential Bd prevalence as potential refuges (free Bd). At the amphibian assemblage level, we found a non-relationship with amphibian phylogenetic signals, but a significantly negative correlation between observed species richness and Bd prevalence indicated a potential dilution effect at the landscape scale. Our model may identify potential susceptible species and areas at risk of Bd presence which could be used to prioritize regions for amphibian conservation efforts and assess species and assemblage risk

Monitoring population dynamics is of fundamental importance in conservation but assessing trends in abundance can be costly, especially in large and rough areas. Obtaining trend estimations from counts performed in only a portion of the total area (sample counts) can be a cost-effective method to improve the monitoring and conservation of species difficult to count. We tested the effectiveness of sample counts in monitoring population trends of wild animals, using as a model population the Alpine ibex (Capra ibex) in Gran Paradiso National Park (Italy), both with computer simulations and using historical census data collected over the last 65 years. Despite sample counts could fail to correctly estimate the true population abundance, sampling half of the target area could reliably monitor the trend of the target population. In case of strong changes in abundance, an even lower proportion of the total area could be sufficient to identify the direction of the population trend. However, when there is a high yearly trend variability, the required number of samples increases and even counting in the entire area can be ineffective to monitor population dynamics. Lastly, the effect of other parameters (such as which portion of the area is sampled or the detectability) was marginal, but these should be tested case by case. Sample counts could therefore constitute a viable alternative to assess population trends, allowing for important, cost-effective improvements in the monitoring of wild animals of conservation interest.