No abstract

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'.

It is often difficult to compare studies examining the effects of endectocides on dung fauna because of different experimental approaches, for example, active ingredients (eprinomectin, doramectin, ivermectin, moxidectin) and formulations (injectable, pour‐on, spiked). To gain a better understanding, we performed a quantitative meta‐analysis using 22 studies to assess the overall effect of endectocide residues on the occurrence (presence or absence) and abundance of aphodiine dung beetles. Our results document a positive effect on the occurrence of adult beetles, indicating that adults tend to be attracted to dung with residues. Conversely, larvae are less likely to occur in the presence of residues. Thus, either adults that colonize dung with residues do not lay eggs or, more likely, the larvae that hatch from these eggs die early in development. Abundance of adult and larval stages was shown to be significantly reduced in dung containing residues. When individual endectocides were compared, only ivermectin demonstrated a significantly negative effect on the abundance of both adults and larvae, possibly owing to a small sample size for other agents. In laboratory studies, only dung “spiked” with endectocides reduced the abundance of larvae, whereas during field research, only pour‐on applications were shown to reduce the abundance of larvae. The present study further documents the nontarget effects of endectocide residues on dung‐dwelling organisms, provides robust evidence on the consequences of different application methods, and emphasizes the need for standardized methodological techniques in future studies. Environ Toxicol Chem 2020;39:863–872. © 2020 SETAC

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.

Two experiments were performed to analyze how anurans (Bufo marinus) use binocular cues to gauge the distance of their prey. In the first, bilateral lesions of the nucleus isthmi eliminated the major source of input from the ipsilateral eye to the tectum. These lesions did not disrupt the animals' ability to use binocular cues to judge distance, suggesting that frogs and toads may not employ binocular disparity-selective cells to assess prey distance. They may instead use a scheme more overtly akin to triangulation, with each tectum providing an output signal encoding the angular position of the prey with respect to the contralateral eye and with distance extracted from the difference between these tectal outputs. In the second experiment, prisms imposed large (13.5 degrees) vertical disparities between the two eyes' images. The toads continued to use binocular cues. The added vertical disparities, like added horizontal ones, caused toads to undershoot their prey. Thus the binocular system must tolerate such vertical disparities and fail to distinguish them from horizontal ones.