RETRACTED ARTICLE: Tree species diversity predicts aboveground carbon storage through functional diversity and functional dominance in the dry evergreen Afromontane forest of Hararghe highland, Southeast Ethiopia

Abstract

Background Regarding the most important ecological challenges, scientists are increasingly debating the relationship between biodiversity and ecosystem function. Despite this, several experimental and theoretical researches have shown inconsistencies in biodiversity and ecosystem function relationships, supporting either the niche complementarity or selection effect hypothesis. The relationship between species diversity, functional diversity, and aboveground biomass carbon was investigated in this study employing standing aboveground carbon (AGC) stock as a proxy measure for ecosystem function. We hypothesized that (i) effects of diversity on AGC can be transmitted through functional diversity and functional dominance; (ii) effects of diversity on AGC would be greater for functional dominance than functional diversity; and (iii) effects of functional diversity and functional dominance on carbon stock varied with metrics and functional traits. Community-weighted means (CWM) of functional traits (wood density, specific leaf area, and maximum plant height) were calculated to assess functional dominance (selection effects). As for functional diversity (complementarity effects), multi-trait functional diversity (selection effects) indices were computed. We tested the first hypothesis using structural equation modeling. For the second hypothesis, the effects of environmental variables such as slope, aspect, and elevation were tested first, and separate linear mixed-effects models were fitted afterward for functional diversity, functional dominance, and the two together. Results Results revealed that slope had a significant effect on aboveground carbon storage. Functional diversity and functional dominance were significant predictors of the aboveground carbon storage (22.4%) in the dry evergreen Afromontane forest. The effects of species richness on aboveground carbon storage were mediated by functional diversity and functional dominance of species. This shows that both the selection effects and the niche complementarity are important for aboveground carbon storage prediction. However, the functional diversity effects (niche complementarity) were greater than functional dominance effects (selection effects). Conclusions Linking diversity and biodiversity components to aboveground carbon provides better insights into the mechanisms that explain variation in aboveground carbon storage in natural forests, which may help improve the prediction of ecosystem functions.

Variation in Tree Density, Biomass and Carbon Stock across an Altitudinal Gradient under Large Cardamom Agroforestry System of Darjeeling Himalaya

“…The large cardamom based traditional agroforestry systems at low altitude-class accumulated the highest biomass and carbon due to the highest number of trees per unit area than the mid-and high-altitude classes. A signi cant and positive in uence of tree species richness on forest biomass and biomass carbon storage along an elevational gradient has also been reported by Wu et al (2017) and Wondimu et al (2021).…”

“…The changes in tree biomass storage along the altitude classes were inversely related (r = − 0.255 * ). A non-signi cant effect of altitude on forest biomass and carbon was earlier reported (Wondimu et al, 2021), while, on the contrary, either direct or inverse relationships between elevation and biomass or carbon stock also exist (Zhang et al, 2018). The varied relationship of altitude classes with biomass storage is attributed to site speci c changes in tree population and their structure.…”

Effect of Forest Management on Carbon Stock of Tropical Moist Afromontane Forest

“…Overall, upper canopy individuals of tropical forests have a significant contribution to aboveground carbon storage. Previous researches also confirmed the effect of functional dominance on carbon storage of a forest stand; the functional traits (wood density, specific leaf area, and maximum plant height) have a noticeable effect on optimum carbon storage [79,85].…”

Functional traits related to competition for light influence tree diameter increments in a biodiversity manipulation experiment

“…This is consistent with the findings of Ziter et al (2013), which suggested that functional dispersion is a significant predictor of aboveground carbon stock in unmanaged forest stands. These findings are echoed more recently by Wondimu et al (2021), where functional dispersion was the best predictor of aboveground carbon stock compared to the functional richness, functional evenness, and functional divergence. Our study indicates that functional dispersion is a less important predictor of DI than neighbourhood competition.…”