Sexual segregation occurs in bats within fragmented remnant woodlands in an agricultural landscape

Abstract

Species-specific responses to landscape configuration and landscape composition have been studied extensively. However, little work has been done to compare intraspecific differences in habitat preferences. Bats have potential as good bioindicator taxa in woodland habitats. Therefore, studying sex differences in responses to woodland and the wider landscape can allow us to gain insight into the relative importance of these habitats for both bats and other taxa. In this study, we aimed to test the predictions that (i) habitat type and connectivity will influence the probability of recording female bats in woodlands and (ii) sex differences in response to habitat type and connectivity will be species-specific. Bat capture data was collected in 206 woodlands over 3 years in England. The probability of detecting females relative to males was modeled in response to a range of woodland characteristics and landscape metrics for six bat species. We recorded sex differences in responses to landscape features in three species. We found a higher probability of capturing female Myotis nattereri in woodlands that were surrounded by a higher proportion of improved grasslands, whereas female Myotis mystacinus were less likely to be recorded in woodlands surrounded by semi-natural vegetation. Female Plecotus auritus were more likely to be recorded in isolated woodlands with less connectivity to other woodlands and where agriculture dominated the surrounding landscape. Our findings indicate that sexual segregation occurs across several UK bat species in response to landscape connectivity and composition. Sexual segregation in response to landscape characteristics in bats should therefore be an important consideration in the management of fragmented agricultural landscapes.

Keywords: chiroptera; citizen science; landscape connectivity; sexual segregation.

FIGURE 1

Kernel density map of woodlands meeting the selection criteria of the study. Black indicates absence of woodland sites and lighter shades indicate areas with woodland sites surveyed.

FIGURE 2

Predicted probability of finding a female relative to a male for (a, b) Plecotus auritus; (c) Myotis nattereri and (d) M. mystacinus, in relation to landscape variables in a fragmented woodland (agricultural area, woodland connectivity, improved grassland and semi‐natural area). Woodland connectivity (b) is calculated using Euclidean nearest neighbor distance (ENN), with a lower ENN value representing a more highly connected woodland and a higher ENN value a more isolated woodland. Model predictions from GLMMs and associated 95% confidence intervals are represented by the solid lines and dashed lines, respectively. Raw data on the proportion of females are represented with open circles with size being proportional to the total number of females.