The status of non-vascular plants in trait-based ecosystem function studies

Abstract

The contributions of non-vascular plants (NVPs) to ecosystem function can be significant in high latitude and high altitude ecosystems and yet their inclusion in trait-based studies is rare. Our aim in this paper is to argue for a more thorough and widespread inclusion of NVPs in trait-based studies of ecosystem function. We focused on three specific objectives, (i) to review and summarize the current knowledge base as to how NVP traits are measured and used in assessing ecosystem function, (ii) to highlight challenges in incorporating vascular plants (VPs) and NVPs together in trait-based studies, and (iii) discuss a framework by which VPs and NVPs can be included in explaining ecosystem function. From a literature search of the Web of Science database we found that the majority of trait-based studies examined mostly vascular plants (VPs), occasionally VPs and NVPs separately, but rarely the two groups together to describe ecosystem function. To date compared to VPs, assessment of the contributions of NVPs to ecosystem function has remained relatively unexplored. Plant communities comprising VPs and NVPs can influence, and in turn be influenced by their habitats. We argue that the response and effect traits of VPs and NVPs are comparable and that classifying NVPs simply as “mosses” and “lichens” and assessing their functions as such is inadequate. We summarized and identified particular measurable traits of both VPs and NVPs that have significant effects on nutrient cycling and community assembly. Future studies in areas where NVPs are abundant should include both VPs and NVPs, aggregated at the finest taxonomic resolution possible to relate ecosystem processes such as cycling of matter and plant community assembly.