Tree size diversity is the major driver of aboveground carbon storage in dryland agroforestry parklands

作者：Florent Noulèkoun, Sylvanus Mensah, Hyung‐Sub Kim, Heejae Jo, Gérard Nounagnon Gouwakinnou, Thierry D. Houéhanou, Michael Mensah, Jesse B. Naab, Yowhan Son, Asia Khamzina · 发表于：Scientific Reports · 年份：2023 · DOI：10.1038/s41598-023-49119-9 · 被引用次数：31 · 研究领域：African Botany and Ecology Studies、Conservation, Biodiversity, and Resource Management、Ecology and Vegetation Dynamics Studies

Abstract Despite the importance of agroforestry parkland systems for ecosystem and livelihood benefits, evidence on determinants of carbon storage in parklands remains scarce. Here, we assessed the direct and indirect influence of human management (selective harvesting of trees), abiotic factors (climate, topography, and soil) and multiple attributes of species diversity (taxonomic, functional, and structural) on aboveground carbon (AGC) stocks in 51 parklands in drylands of Benin. We used linear mixed-effects regressions and structural equation modeling to test the relative effects of these predictors on AGC stocks. We found that structural diversity (tree size diversity, H DBH ) had the strongest (effect size β = 0.59, R 2 = 54%) relationship with AGC stocks, followed by community-weighted mean of maximum height (CWM MAXH ). Taxonomic diversity had no significant direct relationship with AGC stocks but influenced the latter indirectly through its negative effect on CWM MAXH , reflecting the impact of species selection by farmers. Elevation and soil total organic carbon content positively influenced AGC stocks both directly and indirectly via H DBH . No significant association was found between AGC stocks and tree harvesting factor. Our results suggest the mass ratio, niche complementarity and environmental favorability as underlying mechanisms of AGC storage in the parklands. Our findings also highlight the potential role of human-driven filtering of local species pool in r...