Literature review: How do priority effects shape species guilds in deadwood?

Abstract

Deadwood is a key component of forest ecosystems and harbours a high diversity of saproxylic species. The order in which these organisms colonise deadwood can influence subsequent community assembly through priority effects, yet this mechanism remains poorly understood in deadwood systems. In this literature review, I examine which species are known to cause priority effects in deadwood, based on thirteen empirical studies. Across these studies, a broad range of saproxylic fungi and beetle species were found to generate priority effects. The underlying mechanisms were diverse, but niche pre-emption and niche modification emerged as the most commonly identified processes. In addition, external factors such as the seasonal availability of deadwood appeared to influence which priority effects could occur, suggesting potential implications for forest management. In particular, more heterogeneous logging regimes may promote diverse saproxylic community assembly pathways. Despite these findings, knowledge gaps remain. Biases limited the reviewed studies; future research should therefore, for example, include angiosperms, incorporate additional saproxylic groups, address cross-taxon interactions, and adopt longer-term research. Such efforts are needed to improve our understanding of priority effects in deadwood and their relevance for conserving saproxylic biodiversity.