Mammal Research Institute

Abstract Once nearly eradicated from Europe, grey wolves ( Canis lupus ) have recently undergone a remarkable demographic recovery, but their long-term survival remains precarious. By analyzing 1,001 genomes, we uncover a mosaic of distinct evolutionary lineages, not a single recovering population. Northern populations exhibit Asian wolf ancestry, while southern populations preserve ancient Holocene lineages, with dog introgression varying by region. Isolated wolves from the Scandinavian, Italian, and Iberian peninsulas harbored particularly high levels of inbreeding and fixed deleterious mutations. Signatures of genome erosion were widespread across Europe, with many populations falling well short of the minimum size recommended for long-term survival. Our study reveals the complex tapestry of wolf ancestry and variation across Europe, which calls for nuanced, regional conservation plans founded in genetic monitoring.

Fire is an important disturbance in European forests, particularly in the Mediterranean region. However, the effects of climate change on fuel availability and fire weather, combined with the widespread dominance of conifer monocultures, high population density, and the significance of human-caused ignition, support predictions of increasing fire risk in temperate Central Europe – a phenomenon likely to necessitate expanded post-fire forest restoration. The non-intervention approach based on ecological succession is often not favoured over active restoration due to economic considerations or legal requirements. Nevertheless, natural ecosystem recovery has been shown to enable successful tree establishment, support biodiversity, and provide microclimatic benefits. Here, we present data on early (2–5 years) natural tree regeneration following non-stand-replacing wildfires in lowland coniferous forests of Białowieża, northeastern Poland, in relation to burn depth and selected microsite characteristics, collected from sample plots along parallel transects within burnt and unburnt forest sections. Our results demonstrate that fire promoted the establishment of diverse tree taxa, including Pinus, Picea, Quercus, Betula, Populus, and Salix. A higher number of saplings was recorded in burnt plots across all sites, with Pinus and Betula benefiting most from both fire disturbance and burn depth. Furthermore, our findings confirm the importance of fire disturbance for the natural regeneration of Scots pine, which is currently nearly absent in the Białowieża Forest otherwise. Our study contributes to the discussion on fire regimes, post-fire ecosystem recovery, and forest restoration in Central Europe, highlighting the great potential for a non-intervention approach after fire. It also provides baseline information to inform conservation and management strategies in the region.

Harvesting naturally dynamic forests causes losses of habitat quality and functional connectivity. Focusing on Sweden as a case study of high-yield rotation forestry, we provide analyses supporting spatial prioritisation of protection, management and restoration of representative functional forest habitat networks. Habitat suitability index modelling of focal birdspecies was used to analyse how forest naturalness, habitat patch size and functional connectivity affect representative forest habitat networks in Sweden's five ecoregions. Habitat modelling for the least demanding bird species showed that of the mountain ecoregion 57-77% was functional, but in the other three boreal ecoregions only 8-9% were functional. For nemoral forests, the proportions of functional habitat networks were < 3%. More demanding species have even less functional habitat. We highlight the importance of the mountain ecoregion for forest biodiversity conservation, and the urgent need for landscape planning of protection, conservation management and nature restoration in Sweden.

Leptospirosis is a globally-distributed zoonotic disease caused by pathogenic Leptospira spp., affecting humans, domestic animals, and wildlife. Despite its importance, little is known about the ecological and epidemiological aspects of Leptospira spp. infection in wild carnivores, particularly martens. This study investigated the presence of Leptospira spp. in stone martens (Martes foina) and pine martens (Martes martes) in northern Poland using serological (MAT) and molecular (real-time PCR and MLST) methods. Samples from 129 martens collected between 2012 and 2022 revealed an 18% seroprevalence and a 13% PCR-positivity rate. Seroreactivity against six Leptospira spp. serovars was identified, all associated with rodent transmission cycles.. Molecular analysis confirmed the presence of sequence types ST117 and ST110, previously reported in small mammals in Central Europe. Martens are susceptible hosts for Leptospira spp.. Given their adaptability and overlapping habitats with livestock and humans, they also represent valuable targets for integrated surveillance within the One Health framework. This study provides the first evidence of Leptospira spp. sequence types and serological diversity in martens in Poland, and offers valuable insights into the epidemiology of wildlife leptospirosis.

The acceleration of biodiversity loss highlights the need for practical, affordable species monitoring tools. A key requirement of monitoring is the accurate identification of species, a particular challenge with cryptic species. This study introduces a non-invasive footprint identification technology to classify two cryptic sengi species ( Elephantulus myurus and Elephantulus intufi ) - key bioindicators in the rapidly changing Southern African biomes. Front footprints were collected, using a custom Small Mammal Reference Track box, from live-captured individuals that were identified by experts in small mammal taxonomy and verified through genetic analyses. Morphometric features of the footprints (lengths, angles and areas) were extracted using JMP software. Linear Discriminant Analysis, based on nine key variables, achieved a mean classification accuracy of 94–96% across training, validation, and test datasets, robustly distinguishing the two species using a single footprint image. By integrating our field capture locations with data from the IUCN expert-defined ranges and the Global Biodiversity Information Facility, we demonstrate that FIT empowers non-experts to contribute reliable, high-resolution occurrence data. This scalable approach has the potential to transform community-science efforts, improving the accuracy of species distribution maps and ultimately strengthening conservation outcomes. Planned advancements include open-ended track tunnels and expanded machine learning models to monitor more small mammals in at-risk ecosystems. This approach offers a scalable, low-impact alternative to traditional trapping and genetic methods, reduces animal stress, morbidity and mortality, and empowers local communities to enhance data quality and monitoring through integration with traditional ecological knowledge.

Abstract While animal‐attached devices provide the most detailed information on animal behaviour, camera traps have become an increasingly popular non‐invasive alternative in wildlife ecology. Here, we compared activity patterns of wolves ( Canis lupus ) assessed with accelerometers and road‐positioned camera traps in two study areas in Croatia and north‐eastern Türkiye. We used accelerometer data from 37 wolves and camera trap data from 82,375 camera trap days at 358 road locations from 2010 to 2021. We fitted generalised additive mixed models to determine the times of day and parts of the year with the highest and lowest wolf activity and correlated the predictions between accelerometer‐ and camera‐based models. Wolf activity patterns predicted from road‐positioned camera traps and accelerometer data were significantly positively correlated, but the strength of the correlation varied among areas, times of day and seasons. The lowest and highest activity periods showed little overlap between the two methods. In both study areas, camera trap data failed to detect the increase in daylight activity during the pup‐rearing season evident in accelerometer data. Overall, camera traps proved adequate for describing general daily and seasonal wolf activity patterns, while discrepancies between the two methods may largely be attributed to camera placement on roads. In light of the increasing use of camera traps in ecological research, our results highlight the value of animal‐attached devices for tracking individuals and recommend caution when interpreting activity patterns from road‐mounted cameras.

Bird vocalisation has primarily been studied during daylight hours, but research indicates that diurnal species also sing at night. The aim of this study was to determine the prevalence and intensity of nocturnal singing by diurnal bird species across four distinct locations in Poland. We examined the impact of moon illumination, habitat type, predation pressure, and species-specific characteristics on nocturnal singing by diurnal birds. Our findings demonstrate that nocturnal singing by diurnal birds is a relatively common behaviour in Central Europe. We recorded 35 diurnal species at night, comprising 76% of all detected species during the nocturnal observations. The intensity of nocturnal singing by diurnal birds varies across orders, families, and even individual species. Birds tended to sing less at the beginning of the night, potentially due to physiological recovery during sleep, but then increase their vocal activity, peaking just before sunrise when the environment begins to be illuminated. We found that more diurnal birds sang in open areas compared to forested habitats, probably due to the greater availability of light in open spaces and reduced predation pressure from owls. We also observed a positive relationship between moon illumination and both the probability of singing and the number of songs produced by both diurnal and nocturnal species, underscoring the significant role of natural light in stimulating night singing. Furthermore, we noticed that the number of species singing at night was higher when diurnal predators were present around the recording locations, suggesting that birds may intensify their nocturnal vocalisations to avoid the threat of daytime predators. In conclusion, nocturnal singing by diurnal birds is a complex phenomenon influenced by various environmental factors that impact its occurrence and intensity.

Survival and cause-specific mortality rates are vital for evidence-based population forecasting and conservation, particularly for large carnivores, whose populations are often vulnerable to human-caused mortalities. It is therefore important to know the relationship between anthropogenic and natural mortality causes to evaluate whether they are additive or compensatory. Further, the relation between survival and environmental covariates could reveal whether specific landscape characteristics influence demographic performance. We used telemetry data on 681 Eurasian lynx (Lynx lynx), a model apex predator with large spatial requirements, that were tracked across their European distribution. Through time-to-event analyses, we sought to determine the variables associated with differences in their survival. Illegal killing was the main cause of mortality (33.8%), and mortality rates were similar in protected and hunted populations (8.6% and 7.0% per year, respectively). Survival varied greatly across populations (70-95% per year). Across all study sites, higher hunting and anthropogenic mortality rates were partially compensated by lower rates of other mortality causes but not by natural mortality alone. Variation in survival depended on sex (female survival was 1.5 times greater than male survival) and seasonality (highest risk during hunting season and winter), and lower survival rates were correlated with higher human modification of landscapes at both coarse (home range composition) and fine (habitat use within home range) scales. Some variation in survival was driven by unobserved factors, which, given the high rates of human-caused mortalities, including illegal killing, are of foremost concern. Due to the low natural mortality rates in protected and hunted populations, we conclude that anthropogenic causes of mortality are likely close to additive, such that maintaining or increasing refuge habitat with little human disturbance is critical to lynx conservation.