Maintenance of constant functional diversity during secondary succession of a subtropical forest in China

Abstract

Questions: Does the importance of biotic interactions between tree species increase during secondary forest succession? Do functional trait values become increasingly divergent from early towards late successional stages and how is functional diversity affected by trait identity, species identity and species richness effects?Location: Gutianshan National Nature Reserve, Zhejiang Province, southeast China.Methods: Based on 26 leaf and wood traits for 120 woody species, we calculated functional diversity, using Rao's formula for quadratic entropy, trait dissimilarity, defined as half the mean trait-based distance of all species in the community, and functional evenness, defined as the degree to which functional diversity is maximized. We employed randomization techniques to disentangle the effects of trait identity, species identity and species richness on these three components of functional diversity.Results: Against expectations, functional diversity did not show any successional trend because the communities compensated for a loss in trait dissimilarity by distributing the trait values more evenly among the resident species, thus increasing functional evenness. Randomization tests showed that functional diversity was not affected by trait identity, by species identity or by species richness, which indicates that functional diversity was neither determined by particular single traits or by single species with outstanding trait values. Conclusions:The constant functional diversity suggests constant functionality in this subtropical forest, which might temporally maintain stable immigration conditions during the course of succession, and thus provides an explanation why these subtropical forests become more species-rich with time.

Functional Diversity and Its Attribute Factors in the Yunmeng Mountain National Forest Park in Beijing, China

“…This result is consistent with the general conclusion that soil depth and soil type are significant for forest distribution and development in the Beijing Mountains (ZHANG et al, 2014). Soil depth is related to root system volume and nutrient availability (PERRONNE et al, 2014), and hence, influences functional diversity (BOEHNKE et al, 2014). Functional evenness was correlated with litter thickness.…”

“…2008). The reason for this difference is that the elevational gradient from 750 m to 1,414 m is relatively short in the Yunmeng Mountain Forest Park (BOEHNKE, et al 2014). Some other studies on low or middle mountains gave the similar results (PERRONNE, et al 2014;ZHANG, et al 2014;TARDELLA, et al 2016 ).…”

“…These indices were all based on the functional distances between species in functional trait space; they reflect certain theoretical differences (SONG and ZHANG 2013;CASANOVES et al 2011). MFAD combined species with the same trait values into a functional unit; FDp and FDc were based on the sum of the lengths of the dendrogram branches; FEve emphasized the evenness of species traits and abundance; FDiv was related to the abundance distribution within the functional volume; and FDis measured the distance of species from the functional centroid (CASANOVES et al 2011;BOEHNKE et al 2014;ZHANG et al 2015b). The similar results found for these indices in the current study's analysis of functional diversity reflected that they were correlated with each other; as also argued elsewhere, it is preferable to use only a few selected indices in the same study (AUSTRHEIM 2002;ZHANG et al 2013c).…”

Leaf traits in dominant species from different secondary successional stages of deciduous forest on the Loess Plateau of northern China

“…Succession, the sequential replacement of species following a disturbance, is of relevance to changes in the structure and functioning of ecosystems (Prach & Walker 2011). Succession is governed by changes in community assembly processes that can be tracked through species traits (Raevel et al 2012;B€ ohnke et al 2013). Using plant functional traits instead of those of the species might aid in prediction and interpretation of disturbance responses, including in novel ecosystems and successional trajectories that are now appearing (Kahmen & Poschlod 2004).…”

Stochastic assembly in a subtropical forest chronosequence: evidence from contrasting changes of species, phylogenetic and functional dissimilarity over succession

“…Therefore, it is likely that both initial community composition and random immigration may play important roles in community assembly. The mechanisms underlying random immigration may be resulted from weak trait-environment relationship in GNNR3031. Letten et al 32.…”