Data from: Bat communities respond positively to large-scale thinning of forest regrowth

Over half of the world's forests are secondary regrowth and support considerable biodiversity. Thinning of these forests is a widespread management practice that can affect forest species, including echolocating bats and their prey. We compared total activity of 11 bat taxa, foraging activity of six bat guilds and biomass of 11 insect orders across four forest thinning categories in managed remnant eucalypt forests in south-eastern Australia: unthinned regrowth, forest thinned recently (0–4 years) and in the medium term (5–10 years) and reference (mature open forest). Thinning had been carried out at large (˜350 ha) spatial scales. Total bat activity was 60% less and foraging activity was 80% less in unthinned regrowth, compared to reference sites, but activity levels were similar among thinned and reference sites. Insect biomass was greatest in unthinned sites, and while bat activity was related to prey biomass, this relationship was weak in unthinned sites. Together, this suggests that forest structure was more important than prey availability or time since thinning in influencing bat activity patterns. Synthesizing our findings with the broader literature on bats and thinning, we found support for a clutter threshold of 1100 stems ha−1, above which bat activity was markedly lower, across two continents (the USA and Australia) and four broad vegetation types (eucalypt, conifer, deciduous and mixed forests). While elsewhere bats with adaptive traits for open habitats generally respond positively to thinning, in our study, species with traits consistent with clutter tolerance (high call frequency and low wing aspect ratio) had lowest activity levels (up to 22 times) in unthinned regrowth compared to all other forest types. Synthesis and applications. Widespread dense regrowth forest can restrict movement and foraging of bats, even those adapted to clutter. We recommend thinning dense regrowth or plantations to below 1100 stems ha−1 when targeting bat foraging habitat, but effects of thinning on roost habitat and other forest biota require further investigation.Bat activity data with environmental variables and geographic locaitonsData includes all data used in bat models. Columns 1-2 give random effects (site and management unit), column 3 is thinning category. Columns 4:5 are the univariate bat response variables (total activity and foraging activity). Columns 6:28 are multivariate response variables: taxa activity (cols 6:16), guild activity (cols 17:22) and guild foraging activity (cols 23:28). All bat activity are in calls per night (foraging activity measures represent foraging calls or 'feeding buzzes' per night). Columns 29:41 are environmental variables described in Table S1 of the supplementary material of the paper (see attached README file). Columns 42:43 are geographic coordinates (latitude and longitude, WGS84) for each site.thinning.bat.data.csvInsect biomass data with environmental variables and geographic locationsData includes all data used in insect models. Columns 1-2 give random effects (site and management unit), column 3 is thinning category. Column 4 is the univariate insect response variables (total insect biomass). Columns 5:15 are multivariate response variables including biomass for each order. All insect biomass measures are in grams. Columns 16:28 are environmental variables described in Table S1 of the supplementary material of the paper (see attached README file). Columns 29:30 are geographic coordinates (latitude and longitude, WGS84) for each site.thinning.insect.data.cs