A Review of Strong Evidence for the Effect of Functional Dominance on Carbon Stocks in Natural Forest Ecosystems

Abstract

Natural forest ecosystems are very important because of their potential and primary role in carbon (C) sequestration. However, it is not very clear that whether Functional Trait Diversity (FTD) enhances C stocks in them due to the trait values of the most abundant species (the mass ratio effect; measure as a Community Weighted Mean (CWM) and/or the variety of trait values (the niche complementarity effect; measure as a Functional Divergence (FD) within an ecosystem. In this study, I reviewed the most recent, critical, empirical and original research studies about FTD-C stocks relationship to understand the effects of CWM and FD on C stocks in natural forest ecosystems. The results of their studies suggest that strong dominance by tall and conservative species, rather than a set of coexisting species with diverse heights and exploitative nature, results in greatest C stocks in natural forest ecosystems. Thus, functional dominance (CWM effect) rather than FD effect has strong influence on C stocks in natural forest ecosystems. In conclusions, these evidences reflect that presence of dominant species will finally diminish functional divergence. Therefore, further research is needed to include the abiotic and biotic factors of an ecosystem in the conceptual model to critically test the FTD model of C stocks for full understanding.

Water‐limited environments affect the association between functional diversity and forest productivity

“…We expect a positive relationship between tree diversity and annual increment, driven by a combination of niche complementarity and mass ratio effects (Figure 1 ; Ali, 2015 ; Loreau et al, 2001 ; Sonkoly et al, 2019 ). More specifically, we expect niche complementarity (indicated by functional dispersion) to be positively associated with site annual increment, whereas we expect the direction of mass ratio effects (indicated by CWM values) to vary with different traits (Conti & Díaz, 2013 ; Finegan et al, 2015 ; Mensah et al, 2018 ).…”

“…Niche complementarity can be reflected by the functional diversity of a community; a greater variety of trait values in a given community can lead to higher rates of ecosystem function due to more efficient exploitation of resources (Sonkoly et al, 2019 ). Mass ratio effects refer to the composition of a community; the trait values of the most abundant species in a community are expected to have the largest effect on the relationship between diversity and ecosystem function (Ali, 2015 ; Loreau et al, 2001 ; Sonkoly et al, 2019 ). Previous studies have produced contrasting results regarding the relative importance of these two mechanisms to explain BEF relationships (Ammer, 2019 ; Grossman et al, 2018 ; Wright et al, 2021 ).…”