Aim: Plant functional traits summarize the main variability in plant form and function across taxa and biomes. We assess whether geographic range size, climatic niche size, and local abundance of plants can be predicted by sets of traits (trait syndromes) or are driven by single traits.
Location: Eurasia.
Methods: Species distribution maps were extracted from the Chorological Database Halle to derive information on the geographic range size and climatic niche size for 456 herbaceous, dwarf shrub and shrub species. We estimated local species abundances based on 740,113 vegetation plots from the European Vegetation Archive, where abundances were available as plant species cover per plot. We compiled a complete species-by-trait matrix of 20 plant functional traits from trait databases (TRY, BiolFlor and CLO-PLA). The relationships of species' geographic range size, climatic niche size and local abundance with single traits and trait syndromes were tested with multiple linear regression models.
Results: Generally, traits were more strongly related to local abundances than to broad-scale species distribution patterns in geographic and climatic space (range and niche size), but both were better predicted by trait combinations than by single traits. Local abundance increased with leaf area and specific leaf area (SLA). Geographic range size and climatic niche size both increased with SLA. While range size increased with plant height, niche size decreased with leaf carbon content.
Conclusion: Functional traits matter for species' abundance and distribution at both local and broad geographic scale. Local abundances are associated with different combinations of traits as compared to broad-scale distributions, pointing to filtering by different environmental and ecological factors acting at distinct spatial scales. However, traits related to the leaf economics spectrum were important for species' abundance and occurrence at both spatial scales. This finding emphasizes the general importance of resource acquisition strategies for the abundance and distribution of herbaceous, dwarf shrub and shrub species.