64 research outputs found
Soil fauna promote litter mixture effects on nitrogen release but not carbon or phosphorus during decomposition in a subtropical forest
No full textUnderstanding how litter diversity drives decomposition is critical for linking plant diversity to ecosystem functioning. We conducted a 460-day field decomposition experiment using litter mixtures (1–4 species) placed in both fauna-accessible and excluded litterbags in a subtropical forest. Both additive partitioning and trait-based approaches were used to investigate the effects of litter mixing on mass loss and the release of carbon (C), nitrogen (N), and phosphorus (P). Overall, the litter mixtures exhibited limited non-additive effects on litter mass loss and C release, with significant negative selection effects that offsetting the weak complementarity effects. In contrast, N release showed strong positive net diversity effects in fauna-accessible mixtures, driven by significant complementarity and selection effects. Soil fauna amplified the diversity effect on N release but had no effect on P, which displaying primarily additive dynamics. Functional identity (community-weighted mean of leaf toughness and thickness) predominantly predicted litter mass loss and C release, while functional diversity (Rao’s quadratic entropy of litter N concentration) and identity jointly governed litter N release in the presence of fauna. Our findings demonstrate decoupled mechanisms for C and nutrient cycling, where physical traits constrain mass loss and C release while synergistic litter diversity-soil fauna interactions enhance N mineralization, highlighting context-dependent diversity effects and underscoring the importance of integrating multi-element perspectives and faunal interactions to predict biodiversity-ecosystem functioning relationships in detrital systems
Spatial variation in community structure of a subtropical evergreen broad-leaved forest: Implications for sampling design
No full textWith the full survey data for a 24-ha subtropical evergreen broad-leaved forest dynamics plot, we evaluated spatial variation in forest structure characteristics (basal area and aboveground biomass), and calculated the minimal sample size and total sampling area necessary to estimate the forest structure characteristics within 20% (+/- 10%) of the observed values with 95% probability for particular quadrat sizes by using a computer program that is designed to simulate the sampling process by allowing different sized quadrats to be randomly located within the sampling region. We found that (1) based on the 600 20 mx20 m subplots, basal area and aboveground biomass displayed a high degree of variation, with respective coefficients of variation of 27% and 31%; (2) based on the computer simulation analysis, the variability of basal area and aboveground biomass decreased with increasing quadrat size. The number of quadrats required to achieve the specified degree of precision dropped sharply with the increase of quadrat size. However, the total sampling area increased with increasing quadrat size, suggesting that using several small quadrats across the sampling area is more efficient than using fewer larger quadrats. Results of this study are valuable for evaluating the reliability of previous research and may assist researchers in designing effective sampling strategies for future field surveys, particularly in subtropical evergreen broad-leaved forests in China
Spatial variation in community structure of a subtropical evergreen broad-leaved forest: Implications for sampling design
No full textData from: Relationships between rhizosphere microbial communities, soil abiotic properties and root trait variation within a pine species
No full text<p>Rhizosphere microbes play important roles in plant performance and ecosystem functioning. It is becoming increasingly clear that rhizosphere communities vary with soil properties and variation in root traits among plant species. However, less is known about whether and how variation in root traits within plant species influences the rhizosphere microbial communities.</p>
<p>We evaluated the intraspecific root traits variation and explored their associations with bacterial and fungal communities in rhizosphere by focusing on an ectomycorrhizal tree<em> </em>species, i.e., <em>Pinus massoniana</em>, in 22 sites in subtropical China.</p>
<p>The first dimension of the principal component analysis on root traits revealed evidence for the 'conservation' gradient of the root economics space. Overall, root traits explained more variation in fungal communities than in bacterial communities in the rhizosphere. Functional composition of rhizosphere microbial communities changed significantly along the 'conservation' gradient, with fast-growing copiotrophic bacteria and symbiotic ectomycorrhizal fungi were significantly enriched on the 'acquisition' side, while slow-growing oligotrophic bacteria were significantly enriched on the 'conservation' side of the gradient.</p>
<p><strong><em>Synthesis</em></strong>: Our study demonstrates that intraspecific variation in plant roots significantly influence rhizosphere microbial communities, which in turn can influence plant nutrition and therefore plant performance within the community.</p><p>Funding provided by: Chongqing Technology Innovation and Application Demonstration Major Theme Special Project*<br>Crossref Funder Registry ID: <br>Award Number: cstc2018jszx-zdyfxmX0007</p>
Earthworms exert long lasting afterlife effects on soil microbial communities
No full textEarthworms dominate the invertebrate biomass in soils. Although the effects of living earthworms on soil functioning have been extensively studied, the ecological impacts of earthworm cadavers on soil microbiota remain unclear. In a 10-weeks laboratory incubation experiment, we monitored the influence of decomposing earthworm cadavers on the diversity and composition of soil bacterial, fungal and protistan communities. We found that the decomposition of earthworm cadavers decreased alpha diversity and changed the composition of microbial communities in comparison to control soil and soil with living earthworms. Although the functional composition of bacterial communities was not significantly influenced by the presence of dead earthworms, both fungal and protistan communities significantly shifted toward r-selected copiotrophic strategists; fungal communities were significantly enriched in molds and yeasts while protistan communities were enriched in saprotrophs. Our results suggest that dead earthworms play a distinct role in influencing soil microbial communities and associated functioning compared to their living counterparts. They further highlight that there is an increasing need to consider the afterlife effects of soil biota to better predict soil biogeochemical cycling in terrestrial ecosystems
Topographic variation in aboveground biomass in a subtropical evergreen broad-leaved forest in China.
No full textThe subtropical forest biome occupies about 25% of China, with species diversity only next to tropical forests. Despite the recognized importance of subtropical forest in regional carbon storage and cycling, uncertainties remain regarding the carbon storage of subtropical forests, and few studies have quantified within-site variation of biomass, making it difficult to evaluate the role of these forests in the global and regional carbon cycles. Using data for a 24-ha census plot in east China, we quantify aboveground biomass, characterize its spatial variation among different habitats, and analyse species relative contribution to the total aboveground biomass of different habitats. The average aboveground biomass was 223.0 Mg ha(-1) (bootstrapped 95% confidence intervals [217.6, 228.5]) and varied substantially among four topographically defined habitats, from 180.6 Mg ha(-1) (bootstrapped 95% CI [167.1, 195.0]) in the upper ridge to 245.9 Mg ha(-1) (bootstrapped 95% CI [238.3, 253.8]) in the lower ridge, with upper and lower valley intermediate. In consistent with our expectation, individual species contributed differently to the total aboveground biomass of different habitats, reflecting significant species habitat associations. Different species show differently in habitat preference in terms of biomass contribution. These patterns may be the consequences of ecological strategies difference among different species. Results from this study enhance our ability to evaluate the role of subtropical forests in the regional carbon cycle and provide valuable information to guide the protection and management of subtropical broad-leaved forest for carbon sequestration and carbon storage
Correction: Topographic Variation in Aboveground Biomass in a Subtropical Evergreen Broad-Leaved Forest in China.
No full textThe relationship between estimation bias and tree density and mean DBH over 50×50-m subplots in Gutianshan 24-ha plot.
No full text<p>The estimation bias is the percentage overestimate of the NLR coarse root biomass model, compared to the LR model estimate.</p
An illustration of NLR (black line) and LR (red line) to fit power-law allometric relationship of diameter-root biomass on both arithmetic (A,C,E.G) and logarithmic scales (B,D,F,H) for three species and mixed species (A,B for <i>Castanopsis eyrei</i>, C and D for <i>Schima superba</i>, E and F for <i>Pinus massoniana</i>, G and H for mixed species).
No full text<p>An illustration of NLR (black line) and LR (red line) to fit power-law allometric relationship of diameter-root biomass on both arithmetic (A,C,E.G) and logarithmic scales (B,D,F,H) for three species and mixed species (A,B for <i>Castanopsis eyrei</i>, C and D for <i>Schima superba</i>, E and F for <i>Pinus massoniana</i>, G and H for mixed species).</p
Multivariate relationship between tree diversity and aboveground biomass across tree strata in a subtropical evergreen broad-leaved forest
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