Diversity enhances carbon storage in tropical forests

Abstract

Aim Tropical forests store 25% of global carbon and harbour 96% of the world's tree species, but it is not clear whether this high biodiversity matters for carbon storage. Few studies have teased apart the relative importance of forest attributes and environmental drivers for ecosystem functioning, and no such study exists for the tropics. Location Neotropics. Methods We relate aboveground biomass (AGB) to forest attributes (diversity and structure) and environmental drivers (annual rainfall and soil fertility) using data from 144,000 trees, 2050 forest plots and 59 forest sites. The sites span the complete latitudinal and climatic gradients in the lowland Neotropics, with rainfall ranging from 750 to 4350 mm year−1. Relationships were analysed within forest sites at scales of 0.1 and 1 ha and across forest sites along large‐scale environmental gradients. We used a structural equation model to test the hypothesis that species richness, forest structural attributes and environmental drivers have independent, positive effects on AGB. Results Across sites, AGB was most strongly driven by rainfall, followed by average tree stem diameter and rarefied species richness, which all had positive effects on AGB. Our indicator of soil fertility (cation exchange capacity) had a negligible effect on AGB, perhaps because we used a global soil database. Taxonomic forest attributes (i.e. species richness, rarefied richness and Shannon diversity) had the strongest relationships with AGB at small spatial scales, where an additional species can still make a difference in terms of niche complementarity, while structural forest attributes (i.e. tree density and tree size) had strong relationships with AGB at all spatial scales. Main conclusions Biodiversity has an independent, positive effect on AGB and ecosystem functioning, not only in relatively simple temperate systems but also in structurally complex hyperdiverse tropical forests. Biodiversity conservation should therefore be a key component of the UN Reducing Emissions from Deforestation and Degradation strategy.

Aboveground Biomass and Carbon in a South African Mistbelt Forest and the Relationships with Tree Species Diversity and Forest Structures

“…More specifically, it was found that species richness was significantly and positively correlated with AGC. Indeed, it is a well-known pattern, especially at the global scale, that carbon stocks increase with increasing diversity [27,29,65]. The positive relationships between tree species diversity and carbon stocks in this study supports the idea that diversity-carbon patterns are also identifiable even at smaller spatial scales.…”

“…Multispecies allometric equations have extensively been studied and offer possibilities to accurately estimate forest biomass at smaller scales, and to elucidate the relationships of forest biomass with stand variables. Recent studies have shed light on the influence of forest stand variables and tree species diversity on the forest biomass and carbon stocks [25][26][27], and how these relationships can serve not only to suggest appropriate management strategies to increase carbon storage [20], but also to test niche complementarity and selection effect hypotheses [28,29]. The niche complementary hypothesis suggests that higher diversity in forest ecosystems would allow a greater variety of functional traits and provide opportunities for efficient resource utilisation, thereby increasing ecosystem functions (for example, carbon storage).…”

Drought can favour the growth of small in relation to tall trees in mature stands of Norway spruce and European beech

“…Many current silvicultural guidelines strive for more heterogeneous stands (Utschig et al 2011;Pretzsch and Zenner 2017) as they may provide many ecosystem goods and services Poorter et al 2015;Mensah et al 2016;Dieler et al 2017) better than monocultures. The finding that small trees benefit in relation to tall trees from dry years and on dry sites (see also Pretzsch and Biber 2010) means that structural heterogeneity, as aimed at by many modern silvicultural guidelines, is easier to maintain on poor dry sites.…”

Análise Fitossociológica e Valor de Importância em Carbono para uma Floresta Estacional Semidecidual

“…Além disso, atributos florísticos e fitossociológicos contribuem diretamente para determinação da biomassa e carbono em florestas tropicais (Poorter et al, 2015). A contribuição de cada espécie para o estoque de biomassa e carbono depende da sua abundância e também das propriedades funcionais de seus indivíduos, como seu tamanho e densidade da madeira (Fauset et al, 2015).…”