Global quantitative synthesis of effects of biotic and abiotic factors on stemflow production in woody ecosystems

Abstract

Aim: Stemflow has been increasingly recognized as an indispensable component in water and nutrient budgets within vegetated ecosystems. Here we aim to quantify the stemflow percentage (St, %) of incident precipitation (i.e. stemflow production) at a global scale, and to provide a systematic evaluation on how biotic and abiotic factors affect St. Location: Global. Time period: 1970–2019. Major taxa studied: Woody plants (trees and shrubs). Methods: We compiled a global stemflow dataset from 234 peer-reviewed papers, which included 488 observations of St and the related biotic (stand characteristics) and abiotic factors (climate variables) at 283 sites within terrestrial woody plant ecosystems. We explored the global pattern of St and performed a machine learning method (boosted regression trees) to model the effects of biotic and abiotic variables on St. Results: Globally, the median (interquartile range, IQR) St was 2.7% (1.0–6.3%). We found that St in arid zones (type B in the Köppen-Geiger climate classification) was significantly higher (p