Long‐term water balance partitioning explained by physical and ecological characteristics in world river basins

For decades, scientists have debated the relation between physical attributes and vegetation and the partitioning of rainfall ( P ) into evaporation ( E ) and run‐off ( R ) in basins. Physical and ecological processes explain the long‐term behaviour of E via water or energy limitations. Needed are similar globally applicable frameworks for describing the production of streamflow and its interaction with factors influencing E , to produce long‐term patterns of E – R partitioning. Here, we analyse 131 independent river basins that flow naturally (or with minimum intervention to their flow) in three major world regions (tropical, temperate, and boreal). We relate water balance partitioning to physical and ecological attributes in these basins to show how P partitioning into E and R is significantly related to the amount of forest and Shrub‐Grass‐Savannas cover in tropical and temperate basins and mostly influenced by slope and Shrub‐Grass‐Savannas cover in boreal basins. Our results highlight that in tropical and temperate basins, if not limited by water, partitioning tends to be equally distributed between E and R as forest cover increases. When Shrub‐Grass‐Savannas cover increases, E dominates, indicating water limitations. In boreal basins, the partitioning does not respond to forest cover, potentially due to the effects of snowmelt and geomorphology. According to normalized difference vegetation index observations, the dominance of E is more related to land cover and seasonality than to vegetation activity. Current processes including deforestation in the tropics, forest die‐off in temperate regions, and afforestation in boreal regions can influence other societally important environmental processes, such as the production of river flow regimes.