Environmental drivers of plant distributions at global and regional scales

Abstract Aim How environmental factors drive plant distribution across the globe is one of the most fundamental questions in ecology. Nevertheless, the relative importance of different environmental factors in driving plant distributions across spatial scales and among plant groups is not clear. This study aims to disentangle how plant–environment relationships vary with latitude and among plant taxa. Location Global. Time period Present day. Main taxa Plant taxa including angiosperms, gymnosperms, pteridophytes and bryophytes. Methods We obtained global distribution occurrence data of mass plant groups (625 families, 6,221 genera, and 54,101 species) from the Global Biodiversity Information Facility (GBIF) database. We used random forest method to quantify the relative effects of 15 environmental factors (including climate, soil and topography) on plant distributions at global and regional scales (divided into different latitude zones). We also used phylogenetic generalized least squares (PGLS) models to investigate the relationships between environmental variables and geographical range size, latitudinal range and limits of plants at the global scale. Results Our analyses revealed the primacy of the effects of climatic variability (temperature seasonality and isothermality) on plant distribution at the global scale. The relative contributions of temperature seasonality and isothermality peaked in tropical areas, whereas solar radiation and annual mean temperature had stronger influence in high‐latitude areas. Wide‐range plant groups tended to occur in areas with higher temperature variability (isothermality and temperature seasonality) and flatter terrain (low slope). Both climate variability and extreme influenced geographical range size, latitudinal range and limits of plants. Main conclusions Our study highlights the significance of climate variability for global plant distributions. Environmental effects upon plant distributions vary across latitudes. The findings imply that environmental factors affecting plant distributions change with geographical scales, suggesting that different geographical and ecological processes should be integrated to explain multi‐scale distribution patterns.