It is well known that survival and the dynamics of wild populations are affected by environmental factors. Recent research has found that, among some species of mammal, differences in environmental conditions between populations of the same species translate into changes in infant and juvenile mortality, but not in the rate of senescence (‘rate of aging’). This has been confirmed among primates and some species of carnivores, but has not been tested on other taxonomic groups, such as rodents. Here, we analyse age-specific survival and mortality on the most extensive capture-mark-recapture data set on Hazel Dormouse available from Lithuania. We used Bayesian survival trajectory analysis (BaSTA) and tested different models of age-specific mortality. Since the Hazel Dormouse population is in decline across its northern distribution, potentially in response to climate change, we divided the data into three periods to assess changes in survival over time. Regional climate data were obtained from the NOAA data service to test the effect of climatic factors on survival during winter and summer respectively. Our results show that, during all three periods, male life expectancies were longer than those of females. We found that the overall level of mortality was high for all three periods, with lowest mortality during the period 1999 - 2004. We found large differences in juvenile mortality and age-independent mortality between the three periods, but not in adult mortality or in the rate of senescence. This is consistent with previous findings on other mammals, supporting the invariant rate of aging hypothesis.

In fragmented forest landscapes, population persistence of arboreal species with limited dispersal ability may strongly depend on the quality of the remaining forest habitat. Using the hazel dormouse ( Muscardinus avellanarius ) as a model species, we studied habitat selection at two spatial scales (home range and within home range) in intensely managed woodlands at its northern distributional range in Denmark. We modelled selection at home range level as the conditional probability of occupancy of 588 nest boxes and nest tubes in 15 managed forests relative to habitat variables measured within 25 m radius. Habitat selection within home ranges was modelled by comparing habitat variables within 3 m radius of triangulated locations by 19 radio-tracked individuals (12 M, 7 F) when active at night with regularly distributed available locations within their home ranges. At both spatial scales, hazel dormice strongly selected sites with high abundance-weighted species richness and high vegetation density of woody plants. On home range level, they furthermore selected for young tree vegetation, while they within home ranges selected for intermediate aged tree stands (maximum trunk circumference: 1.50 m). The predicted probability of presence in nest boxes or nest tubes varied from less than 1% to more than 99% as a combined function of three habitat variables. From May to October, selection for abundance-weighted species richness of woody plants of radio-tagged individuals decreased with date and body weight, suggesting that a diverse food base is particularly important early in their season of activity and for lean and small (growing) individuals. Selection for dense vegetation increased with body mass and mean available vegetation density within home ranges, indicating behavioural variability related to changes in energy expenditure and need for safety among individuals. The study demonstrates that the hazel dormouse has specific habitat requirements related to food and safety that can be accommodated with relatively simple means in managed forests. Graphical abstract

Biodiversity loss is a major challenge. Over the past century, the average rate of vertebrate extinction has been about 100-fold higher than the estimated background rate and population declines continue to increase globally. Birth and death rates determine the pace of population increase or decline, thus driving the expansion or extinction of a species. Design of species conservation policies hence depends on demographic data (e.g., for extinction risk assessments or estimation of harvesting quotas). However, an overview of the accessible data, even for better known taxa, is lacking. Here, we present the Demographic Species Knowledge Index, which classifies the available information for 32,144 (97%) of extant described mammals, birds, reptiles, and amphibians. We show that only 1.3% of the tetrapod species have comprehensive information on birth and death rates. We found no demographic measures, not even crude ones such as maximum life span or typical litter/clutch size, for 65% of threatened tetrapods. More field studies are needed; however, some progress can be made by digitalizing existing knowledge, by imputing data from related species with similar life histories, and by using information from captive populations. We show that data from zoos and aquariums in the Species360 network can significantly improve knowledge for an almost eightfold gain. Assessing the landscape of limited demographic knowledge is essential to prioritize ways to fill data gaps. Such information is urgently needed to implement management strategies to conserve at-risk taxa and to discover new unifying concepts and evolutionary relationships across thousands of tetrapod species.

OBJECTIVES:A recent study from Sweden showed that European hedgehogs may constitute a reservoir for methicillin-resistant Staphylococcus aureus (MRSA), but this host-parasite relationship remains to be investigated in other countries. In this study, we therefore sought to: 1) determine the dissemination of MRSA in European hedgehogs throughout Denmark; 2) investigate determinants of MRSA carriage in hedgehogs; 3) determine the potential for zoonotic transmission of MRSA from hedgehogs to humans; and 4) characterise the detected MRSA on both a phenotypic and molecular level.METHODS:Nasal swabs were taken from 188 dead hedgehogs collected by volunteers throughout Denmark to determine the occurrence of MRSA. Additionally, 16 hedgehog rehabilitators were tested for potential zoonotic transmission of MRSA from hedgehogs to humans. The swabs were incubated in tryptic soy broth supplemented with 6.5% NaCl, followed by spread of 10 μl on Brilliance MRSA 2 agar. One presumptive MRSA colony from each plate was subcultured on 5% blood agar. All S. aureus subcultures were verified by a PCR assay detecting mecA, mecC, lukF-PV, scn, and spa, followed by spa typing.RESULTS:A total of 114 (61%) hedgehogs carried mecC-MRSA, whereas none carried mecA-MRSA. The detected mecC-MRSA belonged to two genetic lineages CC130 (spa-types: t528, t843, t1048, t3256, t3570, t6220, t17133) and CC1943 (spa-types: t978, t2345, t3391, t8835, t16868), 52% of which were spa-type t843 (CC130).The detection rate of mecC-MRSA in the hedgehogs was similar regardless of cause of death, sex, region and habitat type. None of the hedgehog rehabilitators carried MRSA.CONCLUSIONS:This nationwide study confirms a high occurrence of mecC-MRSA in hedgehogs, which could serve as a natural reservoir for this specific type of MRSA. Furthermore, our study did not find signs of zoonotic transmission of mecC-MRSA to hedgehog rehabilitators.

Population expansions of boreal species are among the most substantial ecological consequences of climate change, potentially transforming both structure and processes of northern ecosystems. Despite their importance, little is known about expansion dynamics of boreal species. Red foxes (Vulpes vulpes) are forecasted to become a keystone species in northern Europe, a process stemming from population expansions that began in the 19th century. To identify the relative roles of geographic and demographic factors and the sources of northern European red fox population expansion, we genotyped 21 microsatellite loci in modern and historical (1835–1941) Fennoscandian red foxes. Using Bayesian clustering and Bayesian inference of migration rates, we identified high connectivity and asymmetric migration rates across the region, consistent with source‐sink dynamics, whereby more recently colonized sampling regions received immigrants from multiple sources. There were no clear clines in allele frequency or genetic diversity as would be expected from a unidirectional range expansion from south to north. Instead, migration inferences, demographic models and comparison to historical red fox genotypes suggested that the population expansion of the red fox is a consequence of dispersal from multiple sources, as well as in situ demographic growth. Together, these findings provide a rare glimpse into the anatomy of a boreal range expansion and enable informed predictions about future changes in boreal communities.