Impacts of an omnivorous ungulate on plant communities and soil organic carbon

Ungulates have been shown to affect multiple aspects of ecosystem composition and functions, including species diversity and carbon storage. Specifically, they can impact belowground carbon via both direct and indirect routes – the latter often occurring when ungulates alter plant diversity and/or plant functional traits. To date, the role of indirect routes has been poorly researched, particularly for omnivorous ungulates.

In this study, we investigated both direct and indirect links between an omnivorous ungulate, the wild boar, and soil organic carbon. We estimated wild boar visit frequencies to different survey plots using camera traps, from which we recorded plant species and soil organic carbon.

Weighted average structural equation models suggested wild boar presence was associated with plant communities with more resource-acquisitive traits, which in-turn corresponded to lower soil organic carbon. However, no direct relationships between wild boar and soil organic carbon or plant species diversity were detected.

This work provides, for the first time, empirical evidence on how boar benefit resource-acquisitive plants that can exploit disturbance and rapidly obtain resources to grow quickly, subsequently leading to decreases in soil organic carbon.

Practical implication As a single keystone ungulate species failed to improve both soil carbon storage and plant diversity, our results point towards the importance of securing functionally diverse ungulate communities for improving the contribution of trophic rewilding towards climate change mitigation efforts.

Methods
These data are the results of camera trap, plant species, and soil organic carbon surveys, and the results of online database searches for plant functional trait values. More details can be found in the manuscript Lovell et al. 2025 titled 'Impacts of an omnivorous ungulate on plant communities and soil organic carbon'.