Drivers of subtropical forest dynamics: The role of functional traits, forest structure and soil variables

Abstract

Question How do biotic forest conditions, in terms of plant functional traits and tree basal area, and soil variables influence old‐growth forest dynamics? Location A subtropical old‐growth forest in Southern Brazil. Methods Forest inventories were conducted in 1999 and 2017, in 24 permanent plots of 500 m2. All trees with a circumference at breast height of ≥ 30 cm were measured, identified to the species level, and tagged. We fitted linear models to evaluate the effect of the biotic variables of initial forest communities (tree basal area, trait community‐weighted mean [CWM] and both species and functional diversity metrics) and of soil variables on forest dynamics. These models included biomass dynamics (annual rate of biomass increment and mortality) and demographic rates (recruitment and mortality rates). Furthermore, linear models were used to evaluate the effect of tree survival, recruitment and mortality and biomass increment on the net biomass change. Results We observed a positive effect of species diversity and a negative effect of CWM leaf phosphorus content on the biomass increment. Biomass loss was positively related to basal area and negatively related to the CWM of leaf nitrogen content. Overall, net biomass change was negatively influenced by biomass loss due to mortality. Recruitment rates were negatively affected by soil potassium content and were positively affected by soil pH and functional evenness of the community. Mortality rates were positively predicted by soil clay content and negatively predicted by species diversity. Conclusions Community functional traits, basal area and soil variables predicted growth, mortality and recruitment dynamics of this subtropical old‐growth forest. This work provides important information about the biomass and demographic dynamics of subtropical forests, showing that initial community characteristics influence the gain and loss of biomass and individuals over a period of almost two decades.

Biomass stock and growth are modulated by anthropogenic pressures, canopy structure and tree biodiversity in fragmented Atlantic Rainforest

“…And whilst our data provide some evidence for pioneer species driving biomass gain, the explanatory power was very limited. This suggests the need for more complex hypotheses, looking to incorporate additional environmental predictors including topography (Rodrigues et al 2019), soil (Bordin & Müller 2019), landscape configuration (Hernández-Stefanoniet al 2011), and disturbance presence (Coelho et al2020) and history (Pflugmacher et al 2014). 'Distance to forest edge', as a measure of anthropogenic pressure, is an important component in determining both AGB stocks and AGB change and we have previously explored the direct and indirect pathways driving this edge effect (da Silva et al 2020).…”

Climate factors affect forest biomass allocation by altering soil nutrient availability and leaf traits

“…Soil pH plays a critical role in regulating nutrient storage and availability, thereby influencing the productivity of terrestrial ecosystems (Slessarev et al, 2016; Meng et al, 2019). Furthermore, soil pH influences the composition and function of soil microbial communities, which in turn affect plant physiological processes (Bordin and Müller, 2019; Song and Zhou, 2021; Zheng and Song, 2022), water and nutrient absorption capabilities (Malik et al, 2018; Hu et al, 2022), and ecological adaptability (Hong et al, 2018). As a result, soil pH exerts a strong influence on BGBP (Meng et al, 2019).…”

Canopy Leaf Traits, Basal Area, and Age Predict Functional Patterns of Regenerating Communities in Secondary Subtropical Forests

“…The similarity was greater both in terms of leaf traits and reproductive plus wood density traits, indicating a secondary forest trajectory toward the expected target in terms of the functional composition and, consequently, ecosystem functionality. The functional composition of forest communities is often associated with ecosystem processes and temporal dynamics, representing the effect of the attributes of the most abundant species (mass-ratio theory), instead of the variability of traits (niche complementarity hypothesis), on ecosystem functions (Garnier et al, 2004;Van der Sande et al, 2018;Bordin and Müller, 2019;Rosenfield and Müller, 2020b). Greater similarity with respect to functional composition in these secondary forests may indicate that important ecosystem functions associated with these traits, and encompassing different compartments of the system (e.g., nutrient cycling, trophic interactions), may be recovering as well (Rosenfield and Müller, 2020a).…”