Search

Bat populations are thought to have suffered significant declines in the past century throughout Europe. Fortunately, there are some signs of recovery; for instance, of the 11 species monitored in the UK, population trends of five are increasing. The drivers of past losses and recent trends are unclear; identifying them will enable targeted conservation strategies to support further recovery.We review the evidence linking proposed drivers to impacts on bat populations in Europe, using the results of a previous cross‐taxa semi‐quantitative assessment as a framework. Broadly, the drivers reviewed relate to land‐use practices, climate change, pollution, development and infrastructure, and human disturbance. We highlight where evidence gaps or conflicts present barriers to successful conservation and review emerging opportunities to address these gaps.We find that the relative importance or impacts of the potential drivers of bat population change are not well understood or quantified, with conflicting evidence in many cases. To close key gaps in the evidence for responses of bat populations to environmental change, future studies should focus on the impacts of climate change, urbanisation, offshore wind turbines, and water pollution, as well as on mitigation measures and the synergistic effects of putative drivers.To increase available evidence of drivers of bat population change, we propose utilising advances in monitoring tools and statistical methods, together with robust quantitative assessment of conservation interventions to mitigate threats and enable the effective conservation of these protected species. [ABSTRACT FROM AUTHOR]

Urbanization is a key global driver in the modification of land use and has been linked to population declines even in widespread and relatively common species. Cities comprise a complex assortment of habitat types yet we know relatively little about the effects of their composition and spatial configuration on species distribution. Although many bat species exploit human resources, the majority of species are negatively impacted by urbanization. Here, we use data from the National Bat Monitoring Programme, a long-running citizen science scheme, to assess how two cryptic European bat species respond to the urban landscape. A total of 124 × 1 km2 sites throughout Britain were surveyed. The landscape surrounding each site was mapped and classified into discrete biotope types (e.g., woodland). Generalized linear models were used to assess differences in the response to the urban environment between the two species, and which landscape factors were associated with the distributions of P. pipistrellus and P. pygmaeus. The relative prevalence of P. pygmaeus compared to P. pipistrellus was greater in urban landscapes with a higher density of rivers and lakes, whereas P. pipistrellus was frequently detected in landscapes comprising a high proportion of green space (e.g., parklands). Although P. pipistrellus is thought to be well adapted to the urban landscape, we found a strong negative response to urbanization at a relatively local scale (1 km), whilst P. pygmaeus was detected more regularly in wooded urban landscapes containing freshwater. These results show differential habitat use at a landscape scale of two morphologically similar species, indicating that cryptic species may respond differently to anthropogenic disturbance. Even species considered relatively common and well adapted to the urban landscape may respond negatively to the built environment highlighting the future challenges involved in maintaining biodiversity within an increasingly urbanized world. [ABSTRACT FROM AUTHOR]

Aim We investigated the effects of disease on the local abundances and distributions of species at continental scales by examining the impacts of white-nose syndrome, an infectious disease of hibernating bats, which has recently emerged in North America. Location North America and Europe. Methods We used four decades of population counts from 1108 populations to compare the local abundances of bats in North America before and after the emergence of white-nose syndrome to the situation in Europe, where the disease is endemic. We also examined the probability of local extinction for six species of hibernating bats in eastern North America and assessed the influence of winter colony size prior to the emergence of white-nose syndrome on the risk of local extinction. Results White-nose syndrome has caused a 10-fold decrease in the abundance of bats at hibernacula in North America, eliminating large differences in species abundance patterns that existed between Europe and North America prior to disease emergence. White-nose syndrome has also caused extensive local extinctions (up to 69% of sites in a single species). For five out of six species, the risk of local extinction was lower in larger winter populations, as expected from theory, but for the most affected species, the northern long-eared bat ( Myotis septentrionalis), extinction risk was constant across winter colony sizes, demonstrating that disease can sometimes eliminate numerical rarity as the dominant driver of extinction risk by driving both small and large populations extinct. Main conclusions Species interactions, including disease, play an underappreciated role in macroecological patterns and influence broad patterns of species abundance, occurrence and extinction. [ABSTRACT FROM AUTHOR]

Understanding how parental expenditure reflects food availability and influences reproductive output is a key part of studies of breeding performance. Provisioning behaviour is an important aspect of parental expenditure. We show that Macaroni Penguins Eudyptes chrysolophus have clear sex-specific differences in provisioning behaviour. Females provision chicks throughout rearing and at higher rates than males, which only participate in the later stages. Female provisioning is consistent throughout chick-rearing and appears to relate to a threshold rate governing whether or not chicks survive. The additional expenditure by males (but not females) during the crèche period influenced chick growth and fledging mass of survivors. We suggest a very simple model to account for these sex-specific differences and effects. Interannual variation in parental expenditure resulted in differences in reproductive output between years. Years of lowest expenditure resulted in lowest growth rate of chicks. Sex-specific differences in provisioning were similar among years, however, with a consistent proportion of expenditure by males. [ABSTRACT FROM AUTHOR]