Phylogenetic diversity correlated with above‐ground biomass production during forest succession: Evidence from tropical forests in Southeast Asia

Abstract

1. Enhancing knowledge on the role of evolutionary history during forest succession and its relationship with ecosystem function is particularly relevant in the context of forest landscape restoration for climate change mitigation and adaptation.2. We used fine resolution vegetation and environmental data (soil, elevation and slope) from two large-scale surveys (320 × 1000 m 2 plots in two 10 km × 10 km blocks) in the Upper Mekong to quantify (1) the role of abiotic and biotic (species interactions) factors in community assembly processes and (2) the effect of biodiversity, environmental factors and forest succession on above-ground biomass (AGB).3. We found strong correlation between soil fertility and community structure in the early successional seres, while species interactions played an increasingly important role in older seres, presumably due to species complementary. 4. We detected a significant relationship between AGB and phylogenetic diversity, elevation and soil fertility across successional gradients. Within successional stages, soil fertility was not significantly associated with AGB, while elevation was significantly associated with AGB only in forest <100 years old. Phylogenetic diversity was positively correlated with AGB in the young secondary forest (< 15 years old) but not significantly associated with AGB in older seres. Synthesis.Our results support the hypothesis that abiotic filtering influences species assembly in the initial stages of forest succession, while biotic interactions dominate community assembly processes in older seres. We found that phylogenetic diversity, soil fertility and elevation gradients were strongly predictive of AGB in a secondary tropical montane forest in Southeast Asia. However, elevation may reflect other underlying abiotic gradients, such as water availability.Phylogenetic diversity was significantly associated with AGB only in youngest 1420 | Journal of Ecology SATDICHANH eT Al.itively superior species. Nevertheless, plant AGB tends to increase rapidly early in forest succession (Li et al., 2017) but the rate of AGB accumulation may decrease as stand age increases, and AGB may seres (<15 years old). Considering phylogenetic diversity in restoration plantings and the management of forests younger than 15 years old could enhance forest biomass and the climate mitigation function forest landscape restoration. K E Y W O R D Sabiotic and biotic factors, above-ground biomass, biodiversity, community assembly, ecosystem function, phylogenetic diversity, succession, tropical forest | 1421Journal of Ecology SATDICHANH eT Al.

Evolutionary diversity is associated with wood productivity in Amazonian forests

“…Both taxonomic and evolutionary diversity had no effect on aboveground biomass in intact forests in Amazonia. These results are supported by a previous pan-tropical study that used an overlapping dataset to investigate the role of taxonomic diversity on biomass 26 , and a recent study that investigated the role of evolutionary diversity on biomass during forest succession and found that despite a positive effect of phylogenetic diversity on biomass in early successional forests, there is no effect at later stages of forest succession 45 . Not surprisingly, but contrary to the positive effect of taxonomic and evolutionary diversity on productivity, biomass was strongly determined by functional characteristics (Figure 3; Supplementary Table 5), with variation in wood density being the most important variable in controlling patterns of biomass in these forests 15,26,46 .…”

A remote sensing derived data set of 100 million individual tree crowns for the National Ecological Observatory Network

“…For example, previous work has found that functional and species diversity at local scales promotes biomass and tree growth ( Barrufol et al, 2013 ; Liang et al, 2016 ). Similar findings have been reported for phylogenetic diversity at local scales ( Satdichanh et al, 2019 ). Especially when combining with species data, using the crown data to investigate the scale and strength of these effects will inform the mechanisms of community assembly, ecological stability, and forest productivity.…”

Individual Tree-Crown Detection in RGB Imagery Using Semi-Supervised Deep Learning Neural Networks

“…For example, previous work has found that functional and species diversity at local scales promotes biomass and tree growth (Barrufol et al, 2013; Liang et al, 2016). Similar findings have been reported for phylogenetic diversity at local scales (Satdichanh et al, 2019). Especially when combining with species data, using the crown data to investigate the scale and strength of these effects will inform the mechanisms of community assembly, ecological stability and forest productivity.…”