Junxiang Ding

Introduction: Wetlands are among the most vital ecosystems on Earth, yet they also face severe degradation risks due to intensifying human activities and climate change. Clarifying the response of wetland plant communities to habitat degradation and its key drivers is therefore essential for the effective conservation, restoration, and management of wetland ecosystems. However, how plant community biomass responds to degradation and the underlying drivers remain poorly understood. Methods: Here, we measured plant community characteristics and soil physicochemical properties along a well-characterized degradation gradient of wetlands in the lower reaches of the Yellow River to determine the drivers of variation in plant community aboveground biomass. Results: The results showed that aboveground biomass, community coverage, density, and height of the wetland plant community decreased consistently with intensifying degradation, whereas species diversity showed no significant change. The variation in aboveground biomass was significantly associated with community structural metrics (e.g., coverage, density, height) but not with species diversity. Furthermore, changes in soil nutrient availability rather than water conditions were the dominant environmental factor driving the decline in aboveground biomass with wetland degradation. Discussion: Collectively, these findings underscore the critical role of soil nutrient availability in mediating wetland plant community structure and function under degradation scenarios. This insight is crucial for understanding wetland ecosystem degradation mechanisms and could inform restoration strategies for degraded wetlands.

Aims Clarifying the responses of plant functional traits to environmental changes is crucial for understanding plant adaptation strategies and ecosystem functions. However, most previous studies have mainly focused on aboveground traits, with less attention paid to belowground traits, especially regarding the covariation between leaf and fine-root traits in wetlands. Methods Selecting Phragmites australis, a typical wetland plant in the lower reaches of the Yellow River, as a focal species, we measured leaf traits (specific leaf area, leaf dry matter content, and nitrogen concentration) and fine-root traits (specific root length, root tissue density, and nitrogen concentration), and analyzed associated environmental factors to explore the variation patterns and driving factors of plant traits along a gradient of wetland degradation. Important findings With the intensification of wetland degradation, leaf and fine-root traits of P. australis exhibited a coordinated shift from resource-acquisition to resource-conservation strategies, as indicated by a significant decrease in specific leaf area, leaf nitrogen concentration and root nitrogen concentration, but a marked increase in leaf dry matter content and root tissue density. However, specific leaf area and specific root length were significantly and negatively correlated, with the latter increasing along the degradation gradient, indicating functional divergence in morphological strategies between aboveground and belowground tissues. Further analysis revealed that soil nutrient availability was the key environmental factor driving trait variations following wetland degradation. As nutrient availability decreased, both leaves and fine roots of P. australis shifted toward a resource-conservative strategy characterized by high tissue density and low nitrogen concentration. By integrating leaf and fine-root traits, this study reveals that P. australis adapts to nutrient limitation in degraded wetlands through the coordinated adjustments of aboveground and belowground traits. These findings advance our understanding of plant adaptive strategies under environmental change and provide a theoretical basis for the functional restoration of degraded wetland ecosystems.

Soil compaction often imposes stress on root development and plant survival. However, root anatomical responses that enable persistent root growth and functioning under soil compaction remain unclear. We grew 10 herbaceous species differing substantially in lateral root diameter, in soils with low (1.0 g cm⁻³) and high (1.4 g cm⁻³) bulk density, and assessed root traits including root biomass, anatomical structures, and respiration rates. Greater root thickening upon soil compaction was found in species with thicker first-order lateral roots, mainly due to larger cortical cell size. Both xylem vessel diameter and wall thickness increased more in compacted soils in these species. Despite these anatomical shifts, root respiration rate responded little to soil compaction across most species, likely due to the opposite investment in cortical cells and xylem vessels. Notably, root biomass, independent of root respiration rate and anatomical structures, determined whole-plant growth under soil compaction. Our study reveals two independent strategies of root response to soil compaction: anatomical remodeling for mechanical and metabolic maintenance, and root biomass investment for resource acquisition. These findings offer new insights for breeding and selecting species tolerant to soil compaction and highlight multidimensional strategies of plant adaptation to physical stress.

Plant–microbe interactions are fundamental to biodiversity maintenance and ecosystem functioning, and their assembly is shaped by a complex interplay of ecological and evolutionary processes. However, how these forces jointly influence ectomycorrhizal (EcM) fungal communities, especially those dominant in subalpine forests, remains poorly understood. To address this, we investigated EcM fungal communities associated with 11 species of Pinaceae (Abies, Picea and Pinus) across 195 monodominant stands in the subalpine forests of the Qinghai-Tibetan Plateau. We found that all pine species are consistently associated with a broad phylogenetic range of EcM fungal lineages, and that pine–EcM association networks exhibit low connectance, indicating low partner specificity. Variation in fungal community structure was significantly influenced by host identity, environmental factors and spatial distribution, but not by host phylogenetic relatedness. Notably, fungal taxa from three dominant lineages (Sebacina, Russula and Inocybe) were clustered phylogenetically with globally distributed Pinaceae-associated taxa, pointing to evolutionarily conserved symbiotic associations across biogeographic regions. Together, these results indicate that EcM fungal communities in subalpine Pinaceae forests are assembled through a combination of evolutionary conservatism and environmental filtering. The persistent association with key EcM fungi across Pinaceae species underscores their essential role in supporting tree physiology and forest ecosystem stability in subalpine environments.

The stability mechanisms of ecosystem functions have been a hot topic in ecology. However, in wetland ecosystems, the mechanisms by which biotic and abiotic factors interact to affect ecosystem stability in changing environments remain largely unclear. This study investigated the key factors and underlying mechanisms that regulate the spatial variability of wetland productivity by measuring community productivity, multiple components of biodiversity (i.e. species diversity, community functional composition and diversity) and environmental factors along a well-characterized gradient of wetland degradation in the lower reaches of the Yellow River. The results showed that the spatial variability of productivity in wetlands increased with intensified degradation. The spatial variability of wetland productivity was not related to species richness but was mainly affected by changes in community functional composition and diversity. Furthermore, degradation-induced changes in soil nutrients drove the spatial variability of productivity to increase with shifts in functional composition towards more conservative traits (i.e. higher leaf dry matter content and root tissue density), and to decrease with higher functional trait diversity. These findings reveal the driving mechanism of spatial variability in wetland productivity under degradation, and suggest that reduced nutrient availability, by altering plant resource strategies, can affect the spatial reliability of key ecosystem functions in wetlands.