A method for rapid assessment of bat richness using woodland structure characteristics

Highlights

•Woodland structural characteristics predict bat richness.
•Influence of structure differs between bat guilds.
•Clutter and stems per hectare are suitable predictors.
•We propose a rapid method to assess woodland suitability for bats.



Abstract

1. To conserve and restore forests we need greater and more efficient assessment of their biodiversity. Integrating species monitoring into woodland inventories provides opportunities to develop more targeted and sustainable management plans; however, such monitoring often requires specialist knowledge of species and survey techniques and can be prohibitively costly to undertake. Where such surveys are not a legal requirement, proxy-based biodiversity assessments can provide a rapid and cost-effective method for estimating species assemblages. We propose a method to assess the value of temperate woodland for bats based on measures of woodland structural characteristics that can be readily obtained during routine woodland inventories.

2. We sampled seven woodland characteristics together with bat richness (number of species) in 52 native broadleaved woodlands in England and Wales. We used generalized additive modelling to find the most parsimonious model that also explained the largest amount of variance in bat species richness.

3. The best model included the amount of understory vegetation (clutter) and number of stems per hectare. These woodland characteristics are informative for predicting the presence of several guilds of bats as they relate to a bats’ ability to orientate and fly within a woodland. Our findings indicate that where clutter and stems per hectare are especially low or high, bat richness is markedly reduced.

4. Using woodland characteristics enables practitioners to estimate bat richness at the local level where direct species sampling is not possible or as a tool to target future species surveys. Structural characteristics can be captured during forest inventories without the need for specific taxonomic expertise. Following additional ground-truthing the proposed method could be expanded to cover a broader range of habitats and fauna with general application.