By Fatin Chowdhury ‘19

Although invasive pest species are often associated with threats to biodiversity, new research may indicate that the bark beetle I. typographus creates a conducive environment for the survival of an endangered European bat. A team lead by Dr. Mareike Kortmann of the University of Würzburg recently undertook a project examining the interaction of the bat species Barabastella barastellus within a forest environment following bark beetle infestation. Two parameters — roost selection and foraging activity — were examined within the context of B. barastellus preferences. The researchers hypothesized that forests affected by bark beetles would have greater canopy openings and structural heterogeneity, leading to greater B. barbastellus foraging. It was also hypothesized that spruces killed by the pest would be selected as roosting trees.  

In collecting acoustic survey data, 119 sampling points in the Bavarian National Forest were used, and bat recorders were used to record noises generated at night. Sound-based surveying, remote-sensing laser technology involving light detection, and radio telemetry were utilized to observe preferred bat habitats. Bats were captured and tagged, with the researchers following them to determine their roosting sites.  The diameters at breast height and tree height were measured with the visually estimated amount of bark cover.

The researchers determined that foraging increased following the availability of increased canopy openings due to bark beetle activity. Maternity colonies were found only in trees that had been killed by bark beetles. There was also a preference for dead trees that had larger diameters.

The researchers commented that the human proclivity of clearing damaged trees from forests in a process known as “salvage logging” may have adverse effects on certain species of animals, while other animals may survive better in the resulting environment. Specifically, this study points to the possibility of recognizing bark beetle-infested forests as suitable habitats for B. barbastellus.

References:

1. M. Kortmann, et al., Beauty and the beast: how a bat utilizes forests shaped by outbreaks of an insect pest. Animal Conservation 21, 21-30 (2018). doi: 10.1111/acv.12359.
2. Image retrieved from: https://www.pexels.com/photo/conifer-dawn-daylight-evergreen-167698/