Yuejun He

Forests are key components of global ecosystems, regulating nutrient cycling and energy flow. In karst landscapes, pronounced ground surface heterogeneity generates highly uneven resource distributions, thereby shaping forest community structure and biomass accumulation. Although multiple dimensions of biodiversity are known to influence aboveground biomass (AGB), how ground surface heterogeneity mediates biodiversity and AGB across fine spatial scales in fragmented forests remains unclear. In this study, we quantified ground surface heterogeneity using an entropy-based index across 212 subplots nested within 53 plots in a subtropical karst forest. By integrating multivariate biodiversity metrics and community-weighted traits, we evaluated the pathways through which ground surface heterogeneity regulates biodiversity and AGB. Our analyses revealed that structural diversity was the strongest predictor of AGB, whereas functional composition also contributed positively, suggesting that both selection and complementarity effects were involved. Moreover, at the plot scale, biodiversity and AGB exhibited unimodal responses to ground surface heterogeneity, indicating that AGB peaked at intermediate levels of heterogeneity, potentially reflecting enhanced structural differentiation and resource complementarity. Taken together, these findings demonstrate a clear hierarchical pathway that ground surface heterogeneity drives variations in biodiversity, which subsequently translates into enhanced stand structural diversity, ultimately maintaining higher AGB. This study underscores the central role of moderate ground surface heterogeneity in sustaining forest structural diversity and biomass accumulation, highlighting the importance of integrating habitat variability and structural metrics into forest management and restoration strategies in fragmented ecosystems.

Waxy sorghum ( Sorghum bicolor var. glutinosum) is the principal raw material for Jiang-flavor baijiu, and its grain characteristics can vary across production environments with contrasting soil and climatic conditions. These environmental differences may also influence rhizosphere microbial communities that contribute to plant nutrient acquisition and crop performance. Among these microorganisms, arbuscular mycorrhizal fungi (AMF) are widespread root symbionts with important roles in nutrient acquisition and soil ecological processes. However, although previous studies of liquor-making sorghum have mainly focused on grain composition and bacterial communities, the spatial variation and environmental associations of rhizosphere AMF across major production areas remain poorly understood. This study investigated rhizosphere AMF communities in three major waxy sorghum production bases in Guizhou, China, using high-throughput 18S rDNA sequencing. Soil properties, grain quality attributes, and climatic data were analyzed via canonical correspondence analysis, LEfSe, and partial least squares path modeling. AMF alpha diversity did not differ significantly among the three production bases, whereas community composition showed clear site-associated differentiation, with Paraglomus representing the predominant classified genus in most samples. CCA indicated that AMF community variation was associated with multivariate edaphic, climatic, and topographic gradients; because several environmental variables were strongly collinear, these relationships were interpreted collectively rather than as independent effects of individual factors. Exploratory PLS-PM further indicated that the largest path associations linked the core AMF community with soil properties and soil properties with grain-quality indicators. Given the observational design with one production base and one weather station sampled per region, these relationships represent site-specific associations rather than evidence of causal environmental or microbial effects or region-wide patterns. Overall, these findings provide a baseline for understanding AMF community variation and soil-microbe-crop relationships at the three sampled Jiang-flavor baijiu sorghum production bases.

Generally, a forest community can be viewed as functionally integrated assemblages composed of modular subcommunities representing different functional groups, such as evergreen and deciduous plants, which exhibit distinct trait strategies along the leaf economics spectrum. However, how plant size drives leaf trait differentiation between evergreen and deciduous subcommunities remains unclear. In this study, we surveyed 53 forest plots in a typical subtropical karst forest and measured leaf traits, including specific leaf area (SLA), leaf tissue density (LTD), leaf dry matter content (LDMC), and leaf carbon (LCC), nitrogen (LNC), and phosphorus (LPC) contents, as well as soil physicochemical properties. All woody species were classified into evergreen and deciduous subcommunities based on leaf habit. Relationships among plant size, leaf traits, and soil variables were analyzed using linear regression, principal component analysis, and multiple regression. The results showed that the deciduous subcommunity exhibited significantly greater tree DBH, height, SLA, LDMC, LNC, LPC, and leaf N/P ratio, but lower LCC, C/N, and C/P than the evergreen subcommunity, indicating clear differentiation in leaf trait strategies between the two subcommunities. Additionally, distinct trait responses to increasing plant size in both subcommunities, particularly for SLA, LNC, and C/N, suggest plant size‐dependent trait differentiation. Moreover, the relative effects indicated that evergreen leaf traits were mainly influenced by soil total phosphorus and habitat heterogeneity, whereas deciduous leaf traits were primarily driven by plant size. Overall, our findings demonstrate that modular subcommunities exhibit distinct leaf trait characteristics and resource‐use strategies, with an acquisitive strategy in the deciduous subcommunity and a conservative strategy in the evergreen subcommunity, both closely associated with plant size in degraded karst forests. These results provide new insights into trait‐based community assembly by highlighting size‐dependent differentiation in modular subcommunities, with implications for understanding vegetation functional evolution and informing ecological restoration of degraded karst forest ecosystems.

Severe anthropogenic disturbances have caused significant forest degradation, making the exploration of community assembly mechanisms crucial for developing effective restoration strategies. These mechanisms may vary across size classes due to ontogenetic niche shifts in plants; however, this process remains insufficiently explored. In this study, we surveyed woody plants across five size classes within degraded forests and measured habitat conditions and neighborhood effects, aiming to investigate the size-class dependence of environmental filtering and biotic competition. The results showed that: (1) Due to ontogenetic niche shifts, the assembly mechanisms for seedlings and large trees differed, shifting from varying primarily by environmental filtering to a combination of filtering and competition. (2) These mechanistic differences resulted in the β-diversity among smaller size classes being primarily driven by species turnover and balanced variation in abundance, whereas nestedness and abundance gradients became the main drivers of structural dissimilarity among larger size classes. (3) At the family level, dominant families achieved intraspecific and interspecific coexistence through ontogenetic niche shifts and differentiated size structures. Overall, the relative importance of environmental filtering and biotic competition shifts significantly across size classes. These findings emphasize that forest restoration practices must account for the differentiated requirements of plants at different developmental stages. Based on these findings, we propose targeted forest restoration strategies to provide guidance for forest recovery efforts.

The poor soil nutrients in the degraded karst region frequently restrict vegetation growth. Soil bacterial communities are essential drivers of biogeochemi

The CSR framework reflects the ecological strategies of competition (C), stress tolerance (S), and ruderal (R) that plants employ to adapt to disturbances. This framework provides a robust foundation for exploring community assembly and successional dynamics within degraded ecosystems such as karst. However, the influence of functional traits and species diversity on ecological strategic trade‐offs during vegetation succession remains unclear. The space‐for‐time substitution method was employed to examine the influence of functional traits and species diversity on ecological strategic trade‐offs during vegetation succession. Five successional stages were identified in the karst community: herb, herb‐shrub transition, shrubbery, shrub‐tree transition, and Tree forest. For each stage, five 100 m × 100 m plots were established, with each plot containing four 10 m × 10 m subplots, resulting in a total of 25 plots and 100 subplots. Plant leaf traits from 2503 individuals of 160 woody species were measured and quantified for CSR components at individual and community levels. The redundancy analysis (RDA), Mantel tests, and a random forest model were applied to explore associations in CSR strategies, diversity, and functional traits. Our results revealed a strategic trade‐off, with a shift from the dominance of the S strategy to increased contributions from C and R strategies at both individual and community levels as vegetation succession progressed. This transition was closely associated with woody species diversity and leaf macronutrient traits of carbon, nitrogen, and phosphorus. RDA and Mantel test results further indicated that Hill numbers ( q = 0, q = 1), leaf water content, and leaf carbon content were key determinants of ecological strategy shifts. Additionally, the random forest model identified soil pH as the strongest predictor of the C strategy, whereas Hill number ( q = 0) was the primary determinant of S and R strategies. In conclusion, the dominance of the S strategy in the early successional stages gradually shifted toward C and R strategies during succession progress. There were strategic trade‐offs of CSR associated with species diversity and leaf functional traits, embodied in S relative to C and R strategies.

Plant invasions severely threaten natural ecosystems, and invasive plants often outcompete native plants across various ecosystems. Arbuscular mycorrhizal (AM) fungi, serving as beneficial microorganisms for host plants, can greatly influence the competitive outcomes of invasive plants against native plants. However, it remains unclear how AM fungi alter the competitive balance between native and invasive species. A competitive experiment was conducted using an invasive Eupatorium adenophorum paired with a native congener Eupatorium lindleyanum. Specifically, both species were inoculated with (M⁺) or without (M⁻) the fungus Glomus etunicatum under intraspecific (Intra‐) and interspecific (Inter‐) competition. Plant traits were measured and analyzed regarding the growth and nutrition of both species. The results exhibited that the AM fungus significantly increased the height, diameter, biomass, C, N, and P acquisition of both the invasive E. adenophorum and the native E. lindleyanum. The root mycorrhizal colonization and the mycorrhizal dependency of native E. lindleyanum were greater than those of invasive E. adenophorum. Under M⁺, the Inter‐competition inhibited the growth and nutrition of invasive E. adenophorum compared to the Intra‐ competition. Further, native E. lindleyanum exhibited higher competitiveness than invasive E. adenophorum in growth and nutrition. Meanwhile, the AM fungus significantly improved the competitiveness of native E. lindleyanum over invasive E. adenophorum. In conclusion, AM fungus improved the competitive advantage of native E. lindleyanum over invasive E. adenophorum in growth and nutrition, potentially contributing to native species competitively resisting the invasion of exotic species. These findings emphasize the importance of AM fungi in helping native plants resist the invasion of exotic plants and further contribute to understanding plant invasion prevention mechanisms.