How environmental factors drive plant distribution across globe is one of the most fundamental questions in ecology. Plant distributions may be shaped by various environmental factors, such as climate, topography and edaphic factors. Nevertheless, it is not clear about the relative importance of different environmental factors in driving plant distribution across spatial scales and among plant groups. This study aimed to disentangle how plant–environment relationships vary with latitude and among plant taxa including angiosperms, gymnosperms, pteridophytes and bryophytes.

Location: Global

Main taxa: Plants

Results: Our analyses revealed the primacy of climatic variability (temperature seasonality and isothermality) on plant distribution at the global scale. The relative contribution of temperature seasonality and isothermality peaked in tropical areas, whereas solar radiation and annual mean temperature had stronger influence at high-latitude areas. We also found wide-range plant groups tend to occur at area with higher temperature variability (isothermality and temperature seasonality) and flatter terrain (low slope). Climate extremes (low temperature and low solar radiation) determined plant distribution range and limits across latitude. Soil and topography had diverse thought less important effects (related to climate) on broad-scale plant distribution patterns.

Main Conclusions: Our study highlights the significance of climate variability for global plant distributions and climate extremes at higher latitude areas. Environmental effects of plant distributions vary across latitude. The findings imply that our understandings on environmental factors affecting plant distributions rely on the geographical scales that we focus on, suggesting that different geographcial and local ecological processes should be integrated to explain multi-scale distribution patterns.

We collected global distribution occurrence data of plant groups (625 families, 6,221 genera, and 54,101 species) from GBIF database. We used random forest to quantify the relative importance 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 general least square (PGLS) models to investigate the relationship between environmental variables and geographical range size, latitudinal range and limits of plants at the global scale.