Increasing levels of road noise are creating new anthropogenic soundscapes that may affect wildlife globally. Bats, which form about a third of all mammal species, are sensitive bioindicators, and may be particularly vulnerable because of their dependency on echolocation. Here we present the first controlled field experiment with free-living bats. Using a Before-After-Control-Impact phantom road experimental design, we examine the impacts of traffic noise on their activity and feeding behaviour. Disentangling the impacts of traffic noise from other co-varying exposures such as habitat quality, the experiment demonstrates a significant negative effect on the activity of each of the five, ecologically different, species (genus for Myotis spp.) examined. This suggests that the results are widely applicable. The negative effects are largely attributable to noise in the sonic spectrum, which elicited aversive responses in all bat species tested,whereas responses to ultrasoundwere restricted to a single species. Our findings demonstrate that traffic noise can affect bat activity at least 20m away from the noise source. For Pipistrellus pipistrellus and Pipistrellus pygmaeus, feeding behaviour, as well as overall activity, was negatively affected. Ecological Impact Assessments are therfore needed wherever there are significant increases in traffic flow, and not just when new roads are built. Further research is required to identify effective mitigation strategies, to delineate the zone of influence of road noise, and to assess whether there is any habituation over time.

1. Bats are important components of agricultural ecosystems. However, little is known about the extent to which bats use linear features when foraging and commuting in agricultural settings, when compared to the interior of fields. 2. As part of a large-scale citizen science project, bat detectors were placed in the centre of agricultural fields (arable and pasture) and along linear features (intensively managed hedgerows, sympathetically managed hedgerows and treelines). 3. Our results show that all 10 of the bat species groups identified were found both along linear features and in the middle of agricultural fields. Of the five species groups analysed further, all had significantly more bat activity along linear features compared to the middle of fields, except for Nyctalus noctula. However, our results showed that 29% of calls from Rhinolophus ferrumequinum were recorded in the middle of agricultural fields, compared to only 10% for Pipistrellus pipistrellus. Bat activity was more likely to be associated with treelines compared to other linear feature types. 4. Our results highlight the importance of linear feature management to bat conservation, but also the need to consider field centres during survey design and Environmental Impact Assessments.

Artificial light at night (ALAN) can have negative consequences for a wide range of taxa. However, the effects on nocturnal mammals other than bats are poorly understood. A citizen science camera trapping experiment was therefore used to assess the effect of ALAN on the activity of European hedgehogs (Erinaceus europaeus) at supplementary feeding stations in UK gardens. A crossover design was implemented at 33 gardens with two treatments—artificial light and darkness—each of which lasted for one week. The order of treatment depended on the existing lighting regime at the feeding station: dark treatments were applied first at dark feeding stations, whereas light treatments were used first where the station was already illuminated. Although temporal changes in activity patterns in response to the treatments were noted in some individuals, the direction of the effects was not consistent. Similarly, there was no overall impact of ALAN on the presence or feeding activities of hedgehogs in gardens where supplementary feeding stations were present. These findings are somewhat reassuring insofar as they demonstrate no net negative effect on a species thought to be in decline, in scenarios where the animals are already habituated to supplementary feeding. However, further research is needed to examine long-term effects and the effects of lighting on hedgehog prey, reproductive success and predation risk.

Context: The importance of habitat connectivity for wildlife is widely recognised. However, assessing the movement of species tends to rely on radio-tracking or GPS evidence, which is difficult and costly to gather.Objectives: To examine functional connectivity of greater horseshoe bats (GHS,Rhinolophus ferrumequinum) at a local scale using Circuitscape software; comparing our results against expert opinion ‘fly ways’.Methods: Expert opinions were used to rank and score five environmental layers influencing GHS movement, generating resistance scores. The slope and resistance scores of these layers were varied, and validated against independent ground truthed GHS activity data, until a unimodal peak in correlation was identified for each layer. The layers were combined into a multivariate model and re-evaluated. Radio-tracking studies were used to further validate the model, and the transferability was tested at other roost locations.Results: Functional connectivity models could be created using bat activity data. Models had the ability to be transferred between roost locations, although site-specific validation is strongly recommended. For all other bat species recorded, markedly more (125%) bat passes occurred in the top quartile of functional connectivity compared to any of the lower three quartiles.Conclusion: The model predictions identify areas of key conservation importance to habitat connectivity for GHS that are not recognised by expert opinion. By highlighting landscape features that act as barriers to movement, this approach can be used by decision-makers as a tool to inform local management strategies.

Context: Habitat suitability models (HSM) have been used to understand the impacts of landscape-scale habitat connectivity and gene flow mostly by assuming a regular decrease in the cost of movement as habitat improves. Yet, habitat selection and gene flow are governed by different behavioural processes which may limit the reliability of this approach as individuals are likely to disperse through unsuitable habitat for breeding. Objectives: The aim of this study was to identify the optimal relationship between gene flow and HSMs for two bat species (Myotis bechsteinii and Eptesicus serotinus) in Britain by testing a range of nonlinear negative exponential functions for the transformation of HSMs into resistance surfaces. Methods: We modelled habitat suitability using a hierarchical, multi-level approach that integrates models across three nested levels. Then, we measured the relationship between published genetics data of both species and six negative exponential transformations of the predicted outputs. Results: The two most extreme transformations provided the best fit to genetic data for both M. bechsteinii (c = 32; R² = 0.87) and E. serotinus (c = 16; R² = 0.42). The negative linear transformations had the poorest fit. Conclusions: These results suggest that bats are able to disperse through areas of poor habitat for breeding, but will avoid the most unsuitable areas. We recommend comparing multiple transformations of HSMs at different resolutions to gain a more accurate representation of gene flow across heterogeneous landscapes and to inform cost-effective, targeted management.