Timing and synchrony of birth in Eurasian lynx across Europe.

The ecology and evolution of reproductive timing and synchrony have been a topic of great interest in evolutionary ecology for decades. Originally motivated by questions related to behavioral and reproductive adaptation to environmental conditions, the topic has acquired new relevance in the face of climate change. However, there has been relatively little research on reproductive phenology in mammalian carnivores. The Eurasian lynx (Lynx lynx) occurs across the Eurasian continent, covering three of the four main climate regions of the world. Thus, their distribution includes a large variation in climatic conditions, making it an ideal species to explore reproductive phenology. Here, we used data on multiple reproductive events from 169 lynx females across Europe. Mean birth date was May 28 (April 23 to July 1), but was ~10 days later in northern Europe than in central and southern Europe. Birth dates were relatively synchronized across Europe, but more so in the north than in the south. Timing of birth was delayed by colder May temperatures. Severe and cold weather may affect neonatal survival via hypothermia and avoiding inclement weather early in the season may select against early births, especially at northern latitudes. Overall, only about half of the kittens born survived until onset of winter but whether kittens were born relatively late or early did not affect kitten survival. Lynx are strict seasonal breeders but still show a degree of flexibility to adapt the timing of birth to surrounding environmental conditions. We argue that lynx give birth later when exposed to colder spring temperatures and have more synchronized births when the window of favorable conditions for raising kittens is shorter. This suggests that lynx are well adapted to different environmental conditions, from dry and warm climates to alpine, boreal, and arctic climates. This variation in reproductive timing will be favorable in times of climate change, as organisms with high plasticity are more likely to adjust to new environmental conditions.

Public perceptions and attitudes toward urban wildlife encounters - A decade of change.

Europe is currently undergoing dynamic land use changes causing the expansion of urban habitat, which is driving wildlife species to colonise conurbations, resulting in an increased likelihood of human-wildlife conflict (HWC). Understanding people's attitudes toward wildlife is essential to manage these conflicts. This study assessed people's attitudes toward urban wildlife, the types of conflicts that existed, preferences for managing conflict situations, and determined any changes in perceptions of urban wildlife over a decade. A questionnaire survey of residents of Krakow, the second-largest city in Poland, was conducted in 2010 (n = 721) and repeated in 2020 (n = 887). We found that encounters with certain urban wildlife such as wild boars, red squirrels, roe deer, brown hares, and red foxes had increased significantly in 2020 compared to 2010. Respondents reported that wild boar and beavers did not show fear when encountering humans. Stone martens were considered the most nuisance wildlife species in 2010, while in 2020 wild boar were the most conflictual wildlife species. There were additional reports of conflicts with roe deer and red foxes. The most frequent HWC responses were personal anxiety, intrusion into property and destruction of crops, which increased significantly over the decade, independent of respondents' gender. Respondents preferred nonlethal methods to mitigate conflicts. The study provides valuable information and knowledge on changes in people's attitudes toward urban wildlife that can help with wildlife management in urban areas. Incorporating perception and attitude data from the public, along with a multi-stakeholder approach that includes wildlife professionals, in the planning and design of future urban environments is critical to minimise HWC.

Frequent infection of urban grass snakes (Natrix natrix) oral cavity with Leptophallus nigrovenosus trematode.

Land disturbances caused by urban development modify and create novel habitats with novel ecological pressures, which in turn may negatively affect remaining wildlife populations, e.g. by altering interspecific interactions. However, it is not clear whether these modified interactions, e.g. parasitism, affect urban wildlife negatively. This is especially true for reptiles, as even parasitism under natural conditions is understudied in this group. We have observed that up to 35% of grass snakes (Natrix natrix) are infected with the trematode Leptophallus nigrovenosus in urban areas of Kraków, while none of snakes sampled in nearby suburban and non-urban forests exhibited this infection. As this trematode typically inhabits the intestine, we suggest that its occurrence in the oral cavity may be a sign of very high infection rates. However, we did not detect any negative effects of observed infection on body size, mass and body condition of affected individuals. On the other hand, competition with other parasite species in suburban and non-urban habitats may be responsible for not detecting L. nigrovenosus in grass snakes from these sites. Nevertheless, interpretation of our findings is difficult, as knowledge on L. nigrovenosus biology is very limited. Our study underlines the necessity to fill the research gap in reptile parasitology.

Decline in body size and female fraction in the grass snake (Natrix natrix, Linnaeus 1758) population after 40 years (Southern Poland).

Depletion of free-living populations is often associated with changes in fitness-related traits, e.g., body size. Ongoing decrease in body size has been reported in most vertebrates, but reptiles remain understudied. Moreover, sexual size dimorphism, commonly observed in reptiles, indicates that environmental pressures on body size may appear sex-specific. This can also result in shifts in sex ratio, an aspect even less studied. We investigated body size and sex ratio in population of grass snake (Natrix natrix) surveyed over 40 years ago in comparison with the current state. We found that both sexes express similar magnitude in body size decline. The current sex ratio does not deviate from 1:1, while in the past, females outnumbered males. The observed changes are likely an outcome of several non-mutually exclusive factors. In the studied area, an increase in road traffic and human presence and a drop in prey availability have been documented. Both factors may exert higher pressure on larger individuals, particularly females, due to their high costs of reproduction. It is recorded here that increase in ambient temperatures and summer duration may additionally enhance the mortality risk and resource requirements. Shifts in body size and sex ratio can catalyze further declines in abundance and reproductive potential of the population.

Effectiveness of different types of hair traps for brown bear research and monitoring.

Non-invasive sampling by hair-trapping is increasingly used worldwide in wildlife research. Despite this rise and the potential of hair samples for ecology and conservation studies, the relative performance of hair collection devices has been rarely tested. Here, we compare the effectiveness of five types of hair traps for brown bears Ursus arctos in the Carpathian Mountains (SE Poland) and test the effects of trap type, season, number of days elapsed since trap installation and trap features on the trapping success in order to provide recommendations for optimal sampling in future studies. The trap types were corral, path-trap, "smola"(beechwood tar) tree-trap, turpentine tree-trap and natural rub. In 2010, we collected 858 hair samples during 2330 inspections of 175 hair traps and found that the most effective traps were smola tree-traps (mean percentage of successful inspections ± SD: 30.2% ± 26.0) and natural rubs (50.8% ± 16.7). Based on this finding, over the following 2 years we focused on 24 smola tree-traps and eight natural rubs. During this long-term survey (2010-2012, 969 inspections, 1322 samples collected) the trapping success increased with time and smola tree-traps achieved similar effectiveness to natural rubs (45.5% ± 29.7 and 45.9 ± 23.4, respectively). We show that when baiting smola tree-traps ten weeks prior to research or monitoring, sampling effectiveness can reach up to 30%. Taking into account the logistical and methodological constraints associated with detecting and using natural rubs for a proper survey design, we recommend using smola tree-traps baited in advance for hair sampling in wildlife studies.

Complex Admixture Preceded and Followed the Extinction of Wisent in the Wild.

Retracing complex population processes that precede extreme bottlenecks may be impossible using data from living individuals. The wisent (Bison bonasus), Europe's largest terrestrial mammal, exemplifies such a population history, having gone extinct in the wild but subsequently restored by captive breeding efforts. Using low coverage genomic data from modern and historical individuals, we investigate population processes occurring before and after this extinction. Analysis of aligned genomes supports the division of wisent into two previously recognized subspecies, but almost half of the genomic alignment contradicts this population history as a result of incomplete lineage sorting and admixture. Admixture between subspecies populations occurred prior to extinction and subsequently during the captive breeding program. Admixture with the Bos cattle lineage is also widespread but results from ancient events rather than recent hybridization with domestics. Our study demonstrates the huge potential of historical genomes for both studying evolutionary histories and for guiding conservation strategies.

Long-range gene flow and the effects of climatic and ecological factors on genetic structuring in a large, solitary carnivore: the Eurasian lynx.

Due to their high mobility, large terrestrial predators are potentially capable of maintaining high connectivity, and therefore low genetic differentiation among populations. However, previous molecular studies have provided contradictory findings in relation to this. To elucidate patterns of genetic structure in large carnivores, we studied the genetic variability of the Eurasian lynx, Lynx lynx throughout north-eastern Europe using microsatellite, mitochondrial DNA control region and Y chromosome-linked markers. Using SAMOVA we found analogous patterns of genetic structure based on both mtDNA and microsatellites, which coincided with a relatively little evidence for male-biased dispersal. No polymorphism for the cytochrome b and ATP6 mtDNA genes and Y chromosome-linked markers were found. Lynx inhabiting a large area encompassing Finland, the Baltic countries and western Russia formed a single genetic unit, while some marginal populations were clearly divergent from others. The existence of a migration corridor was suggested to correspond with distribution of continuous forest cover. The lowest variability (in both markers) was found in lynx from Norway and Bialowieza Primeval Forest (BPF), which coincided with a recent demographic bottleneck (Norway) or high habitat fragmentation (BPF). The Carpathian population, being monomorphic for the control region, showed relatively high microsatellite diversity, suggesting the effect of a past bottleneck (e.g. during Last Glacial Maximum) on its present genetic composition. Genetic structuring for the mtDNA control region was best explained by latitude and snow cover depth. Microsatellite structuring correlated with the lynx's main prey, especially the proportion of red deer (Cervus elaphus) in its diet. Eurasian lynx are capable of maintaining panmictic populations across eastern Europe unless they are severely limited by habitat continuity or a reduction in numbers. Different correlations of mtDNA and microsatellite population divergence patterns with climatic and ecological factors may suggest separate selective pressures acting on males and females in this solitary carnivore.

Occurrence of internal parasites in stone martens (Martes foina) from Cracow and suburbs.

The pine marten Martes martes and the stone marten Martes foina are the only representatives of the genus Martes in Poland. During the last few decades, an intensive synurbisation of stone martens has been recorded. The aim of the study was to assess the level of infection by internal parasites of Martes foina in the Cracow urban area. Eleven necropsies were performed of stone martens killed during animal-vehicle collisions. Additionally, coprological examination of 129 stone marten scats was included. For further analysis, two standard methods, i.e. flotation and decantation, were used. The intensity of infection by parasites was low. Taenia martis was found to be present in one marten individual by necropsy, while Taeniidae helminths and two genera of nematodes, Capillaria and Toxocara, were identified during coprodiagnosis. The diet analysis of stone marten scats revealed a high proportion of two food categories. Percentage frequency of occurrence for plant material and anthropogenic was calculated as 42.3% and 15.4%, respectively. This type of food composition might suggest lower infection by internal parasites in particular species, especially with an indirect life cycle.

Roadless and Low-Traffic Areas as Conservation Targets in Europe.

With increasing road encroachment, habitat fragmentation by transport infrastructures has been a serious threat for European biodiversity. Areas with no roads or little traffic ("roadless and low-traffic areas") represent relatively undisturbed natural habitats and functioning ecosystems. They provide many benefits for biodiversity and human societies (e.g., landscape connectivity, barrier against pests and invasions, ecosystem services). Roadless and low-traffic areas, with a lower level of anthropogenic disturbances, are of special relevance in Europe because of their rarity and, in the context of climate change, because of their contribution to higher resilience and buffering capacity within landscape ecosystems. An analysis of European legal instruments illustrates that, although most laws aimed at protecting targets which are inherent to fragmentation, like connectivity, ecosystem processes or integrity, roadless areas are widely neglected as a legal target. A case study in Germany underlines this finding. Although the Natura 2000 network covers a significant proportion of the country (16%), Natura 2000 sites are highly fragmented and most low-traffic areas (75%) lie unprotected outside this network. This proportion is even higher for the old Federal States (western Germany), where only 20% of the low-traffic areas are protected. We propose that the few remaining roadless and low-traffic areas in Europe should be an important focus of conservation efforts; they should be urgently inventoried, included more explicitly in the law and accounted for in transport and urban planning. Considering them as complementary conservation targets would represent a concrete step towards the strengthening and adaptation of the Natura 2000 network to climate change.

Wolf predation and snow cover as mortality factors in the ungulate community of the Bialowieza National Park, Poland.

Wolf-ungulate interactions were studied in the pristine deciduous and mixed forests of the Bialowieza National Park in 1985-1989. The study period included two severe and two mild winters. The community of ungulates inhabiting Bialowieza National Park consisted of red deer Cervus elaphus, 55% of all ungulates; wild boar Sus scrofa, 42%; and roe deer Capreolus capreolus, moose Alces alces, and European bison Bison bonasus, about 1% each. The average size of red deer groups increased from 2.7 (SD 2.35) in spring and summer to 6.9 (SD 6.84) in autumn and winter. In winter the group size of red deer was positively correlated with the depth of snow cover and negatively correlated with the mean daily temperature. Average group size of wild boar did not change significantly between seasons; it was 6.8 (SD 5.16) in spring and summer and 5.7 (SD 4.67) in autumn and winter. Analysis of 144 wolf scats showed that wolves preyed selectively on red deer. In October-April, Cervidae (mostly red deer) constituted 91% of biomass consumed by wolves, while wild boar made up only 8%. In May-September deer formed 77% of prey biomass, and the share of wild boar increased to 22%. In all seasons of the year wolves selected juveniles from deer and boar populations: 61% of red deer and 94% of wild boar of determined age recovered from wolves' scats were young <1 year old. Analysis of 117 carcasses of ungulates found in Bialowieza National Park showed that predation was the predominant mortality factor for red deer (40 killed, 10 dead from causes other than predation) and roe deer (4 killed, none dead). Wild boar suffered most from severe winter conditions (8 killed, 56 dead). The percentage of ungulates that had died from undernutrition and starvation in the total mortality was proportional to the severity of winter.