Do wolves protect forests? Investigating the link between wolf density, deer browse, and plant recovery

Large ungulate populations can threaten forest regeneration and many rare or declining understory plants, birds, and small mammals. Reintroduction of large predators is often proposed as a remedy to reduce negative ecosystem effects associated with high ungulate populations, but we know little about the effectiveness of this approach. We assessed whether wolves (Canis lupus) can protect forest understory plants from excessive white-tailed deer (Odocoileus virginianus) browse. We planted white oak (Quercus alba), red oak (Quercus rubra), and zigzag goldenrod (Solidago flexicaulis) seedlings across a gradient of wolf density and occupancy time in northern Wisconsin and recorded deer browse and frequency of 11 common understory plants at each site. We found that wolf density and residence time had negative effects on deer browse intensity, but these effects were generally weak except when understory vegetation was abundant. Additionally, the presence of common understory plants decreased a..., , # Do wolves protect forests? Investigating the link between wolf density, deer browse, and plant recovery

Dataset DOI: [10.5061/dryad.905qfttwv](10.5061/dryad.905qfttwv)

## Description of the data and file structure

This dataset contains the data and code required to replicate analyses in Brice et al. (in review), testing the hypothesis that wolves decrease deer browsing and subsequently increase forest regeneration. Data cover 42 sites in northern Wisconsin across a gradient of wolf density and wolf residence time, at which we planted white oak (*Quercus alba*), red oak (*Quercus rubra*), and zigzag goldenrod (*Solidago flexicaulis*) seedlings in the spring of 2022 and 2023. We monitored the seedlings for deer herbivory over 3 summers (2022-2024), and collected data on height growth and surrounding site conditions (e.g., vegetation height, leaf litter depth, canopy cover). During the 2022 field season, we also collected data on 11 common understory plants at each site. Files also in...,