Coarse woody debris (CWD) consists mainly of log, snag, large branch, stump and coarse root. CWD is widely distributed on the forest floor and especially valuable in most of forest ecosystems because it is vital to the global carbon cycling and biodiversity conservation. In particular, increasingly extreme climatic events, such as persistent high temperature, prolonged drought, and tropical cyclones are greatly affecting forest ecosystem function and stability by accelerating tree death, changing the sources of CWD inputs and decomposition processes. Thus, research about CWD decomposition has becoming an ecological hotspot. More and more ecologists have contributed greatly in disentangling the mechanisms on how factors control decomposition process and how CWD nurses biodiversity, which have greatly stimulated the development of CWD ecology. In this review, firstly, we summarized the dominant methodology used in the CWD decomposition study. Then we introduced the scenarios which could be applied for each method. Secondly, we described the morphological, physical and chemical properties of CWD during decomposition, respectively. Thirdly, we overviewed previous studies disentangling factors affecting decomposition dynamics. Briefly, substrate quality, decomposer community and environmental conditions are the main control factors of CWD decomposition. Substrate quality and decomposer community dominate the CWD decomposition process at site scale, with substrate quality regulating the decomposer community with bottom-up effects, while environmental conditions functioning at regional or broad scales. Fourthly, huge amount and diverse types of organisms use decaying CWD as a habitat, many of which are endangered species. It is fundamental to maintain the biodiversity in the CWD ecosystem. Epixylic plants (especially for bryophytes), bacteria, fungi and invertebrates are the common species living on/in the CWD. Invertebrates can utilize CWD in different ways, such as habitat, nourishment and foraging sites, which are species specific. The community composition changed along with decomposition process. The succession of epixylic plants is correlated with the duration of decomposition, while the succession of other types of organisms is mainly driven by the changing substrate quality of decaying CWD. Additionally, we summarized the decomposition dynamics of different structural components (bark vs. xylem) and the interaction between bark and xylem during CWD decomposition which have been overlooked. Finally, as the long decomposition time and the limitation of methodology impeded the progress of revealing the mechanism of CWD decomposition, we made an outlook of future research in the area of decomposition mechanism and biodiversity conservation, and provided methodology that could be of help in stimulating the further development in CWD ecology.

Aims This study primarily aims to investigate the spatiotemporal evolution patterns of fractional vegetation cover (FVC) in the grasslands of Xinjiang section of Tianshan Mountains over the period 2001 to 2020. It seeks to elucidate the determinants of these patterns, emphasizing the influence of vegetation types, livestock farming practices, precipitation levels, and mean annual air temperature. Ultimately, the goal is to contribute important insights that will inform decisions concerning the sustainable management and ecological conservation of these grasslands.

Methods The investigation into the spatiotemporal evolution patterns of vegetation in Xinjiang section of Tianshan Mountains and the factors influencing these patterns leveraged MODIS NDVI remote sensing data spanning two decades. A suite of analytical techniques, including Senʼs Slope Estimator + Mann-Kendall trend analysis, coefficients of variation, and land-use dynamics assessments, were employed to analyze the spatiotemporal variations in grassland FVC.

Important findings The study revealed a general stability in FVC, with the multi-year average varying between 0.33 and 0.42. Notable FVC increases were observed in the northeastern and southwestern low-altitude areas of the range, comprising 3.14% of the analysis area. In contrast, significant FVC declines were predominantly in the Ili River Basin, representing 15.81% of the area studied. The dynamics of grassland FVC were primarily driven by vegetation types and the total value of livestock farming output, each influencing over 29.85% of the variation. When considering the interaction with precipitation and mean annual air temperature, the influence of these factors on FVC increased to above 48.70%. Furthermore, a positive association between FVC and both annual precipitation and average annual temperature was noted, with areas displaying a correlation to precipitation covering 80.84% of the total area, largely encircling the basins flanking Tianshan Mountains range. Meanwhile, a correlation with mean annual air temperature spanned 71.69% of the area, predominantly at higher elevations. These findings offer valuable reference data to support strategic planning for the sustainable use and protection of grassland ecosystems in the Tianshan Mountainous region.

Aims The Leymus chinensis community is one of the most precious natural wealth in China’s grassland resources. However, its productivity is constrained by a variety of global change factors. Although, the invasion of Cenchrus spinifex (hereafter as “invasion”) and drought are two of most important global change factors that significantly affected the productivity of L. chinensis community in the northeast Songnen grassland area, the relevant mechanisms have still not received sufficient attention.

Methods Through the microcosmic control experiments and a complete interaction design with two factors, we explored the mechanism of invasion and drought on the productivity of the L. chinensis community. Factor one was the invasion treatment (invasion vs control), factor two was the water treatment (drought vs normal water), and a total of 10 replications were set up under each treatment, with a total of 40 pots in the experiment.

Important findings The results showed that invasion and drought significantly reduced the aboveground biomass of the L. chinensis community and the dominant species L. chinensis. Soil available nitrogen content and soil arthropod richness significantly decreased under drought treatment, while soil bacterial abundance and arbuscular mycorrhiza fungi (AMF) of the family Glomeraceae increased significantly. The effect of invasion on the effective number of species of soil fungi is moderated by drought, showed that invasion did not affect the effective number of species of soil fungi under normal water conditions, but significantly increased the effective number of species of soil fungi under drought conditions. The results of the structural equation modeling indicated that invasion and drought directly suppressed the L. chinensis community productivity. Drought has indirectly mitigate negative effect on native community productivity by increasing the abundance of dominant soil fungi. In addition, the interaction of invasion and drought suppressed native community productivity by increasing soil fungal community diversity. This study provides a theoretical basis for better protection of grassland productivity and conservation of high-quality forage in the future.

Aims Water and nitrogen (N) availability are two of crucial factors affecting the growth of desert plants, and are sensitive to global climate change. With increasing N deposition and precipitation, the understanding of the responses of leaf N and phosphorus (P) stoichiometry of dominant species in sandy semi-shrub community could provide insights into the adaptive strategies of sand-fixing plants in the Mau Us Sandy Land.

Methods An experiment of N and water addition was conducted in an Artemisia ordosica community in the southern edge of the Mau Us Sandy Land. Soil available N and P concentrations, soil available N:P, leaf N and P concentrations, leaf N:P, and the corresponding homeostasis index of dominant species A. ordosica and Leymus secalinus were measured.

Important findings (1) Soil N and P availability and species identity jointly influenced the response of leaf N concentration, leaf P concentration, and leaf N:P in A. ordosica and L. secalinus to N and water addition, and the leaf N concentration of A. ordosica and L. secalinus showed different responses to treatments. (2) Both A. ordosica and L. secalinus showed higher stoichiometric homoeostasis indices for leaf P than for leaf N, which was closely related to the fact that the growth of A. ordosica and L. secalinuswere both N-limited. (3) The stoichiometric homoeostasis indices of leaf N concentration, leaf P concentration, and N:P in A. ordosica were relatively higher than those of L. secalinus, and A. ordosica adopted more conservative nutrient utilization strategies, while L. secalinus adopted more flexible nutrient utilization strategies. Therefore, A. ordosica was more competitive than L. secalinus in growth in arid and infertile environments. Under the scenarios of increasing N deposition and precipitation, the species composition of the A. ordosica community may change due to the contrasting competitiveness and nutrient utilization strategies between A. ordosica and L. secalinus.

Aims Functional traits can individually or jointly reflect the response of plants to environmental changes and their adaptation strategies and are closely linked to ecosystem functioning. Exploring the functional traits and trait space characteristics of wetland plants is of importance for understanding the mechanisms underlying the ecological adaptability of wetland plants in river floodplains.

Methods We measured 10 functional traits of 30 common herbaceous plants in 5 river floodplains around Wuhan in middle reaches of Yangtze River. We then analyzed the relationships among traits, the quality of trait space, the importance of traits, and the distribution of species in trait space.

Important findings The results showed that variations in functional traits were large among wetland plant species and that trait-trait relationships were generally weak. The quality of trait space increased rapidly when the dimension of space increased from one to four, with the six-dimensional space being of the highest quality. Considering a tradeoff between dimension reduction and space quality, we chose the four-dimensional space for subsequent analyses. In the four-dimensional space, life span, rhizome, plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen content and leaf carbon content were significantly correlated with the axes of the trait space, indicating that they played an important role in shaping the trait space of wetland plants. Sixteen species were located at the vertices of the convex hull, of which ten had high frequencies of occurrence, indicating that these species hold unique trait values and might be more important in shaping the trait space than other species.

Aims Fine roots are important organs for absorbing and transporting nutrients during plant growth and development. Investigating the variation and trade-offs among functional traits of seedling fine roots of different mycorrhizal types is conducive to a more comprehensive understanding of their early survival strategies.

Methods In this study, we analyzed the variation and trade-offs across different mycorrhizal types, root orders and root functional modules. In particular, we measured three morphological traits (specific root length (SRL), root tissue density (RTD), and root diameter (D)), and four chemical traits (total phosphorus (P) content, total carbon (C) content, total nitrogen (N) content, carbon nitrogen ratio (C:N)), in three arbuscular mycorrhiza (AM) and three ectomycorrhiza (EM) tree species seedlings in mixed broadleaf-Korean pine (Pinus koraiensis) forest in the Liangshui National Nature Reserve, Heilongjiang Province.

Important findings The results showed that EM seedling fine roots exhibited higher RTD compared with AM seedlings, potentially due to the colonization patterns of AM fungi which increased root volumes and increased the absorptive capacity of limiting nutrients. Other traits did not differ significantly between the two types of mycorrhiza, with AM seedling roots aligning with a more resource-acquired strategy, in contrast to EM seedlings. As the root order increased, RTD and D of both mycorrhiza-association seedling roots increased significantly, while SRL decreased, indicating a functional shift from absorption to transportation. Concurrently, C content and C:N of roots increased, while the N content of roots decreased with increasing root order. A notable trade-off was observed between morphological and chemical traits of fine roots, suggesting that changes in root functional modules with root order are accompanied by corresponding shifts in root traits. These findings support the root economics spectrum (RES), highlighting the complex interplay between root morphology, chemistry and ecological strategy.

Aims The response of herbaceous and woody plants to environmental stress is an important mechanism for the evolution of ecosystem structure and function in hydro-fluctuation belt of Three Gorges Reservoir. However, the pertinent response characteristics and whether there are group differences in these stress responses are still unclear.

Methods Here, we undertook a meta-analysis of the effects of typical environmental stresses (flooding and drought stress) on the physiological and ecological characteristics of suitable herbaceous and woody plants in the Three Gorges hydro-fluctuation belt, with an aim to reveal the response of suitable plant groups to flooding and drought stress from the perspective of species and life forms.

Important findings The results showed that: (1) Herbaceous plants and woody plants showed obvious growth and development inhibition and adaptive response in physiological and biochemical strategies under environmental stress, mainly manifested in the decrease of biomass and photosynthetic rate of each tissue and organ, the increase of malondialdehyde and proline content, and the initiation of antioxidant enzyme system (superoxide dismutase, peroxidase, catalase). (2) Flooding stress had the strongest negative effect on herbaceous plant biomass, followed by drought stress. Flooding stress had the greatest negative effect on total chlorophyll content and photosynthetic rate of woody plants, followed by drought stress, showing the life-form effect of environmental stress. However, the total chlorophyll content of herbaceous and woody plants was most sensitive to flooding stress, while woody plants showed a certain homeostasis to drought stress. The physiological and biochemical responses of woody plants to flooding stress were more significant than those of herbaceous plants, and the responses were mainly different from those of herbaceous plants in stomatal conductance, malondialdehyde and proline content, and peroxidase activity. The herbaceous plants showed stronger response to drought stress than did woody plants, and the response of total chlorophyll content, water use efficiency and antioxidant enzyme (superoxide dismutase, peroxidase, catalase) activity was different from that of woody plants. (3) The morphological responses of herbaceous and woody plants to different environmental stresses have tissue-specific differences. Herbaceous plants mainly adapt to flooding and drought stress by morphological changes of roots, stems and leaves, while woody plants mainly adapt via morphological changes of roots. In summary, this study presents an integrated view of the morphological and physiological characteristics of herbaceous and woody plants in response to environmental stress in the hydro-fluctuation belt of the Three Gorges Reservoir, which provided a scientific basis for evaluating the potential of different life-form vegetation in the ecological structure and functional restoration in this ecologically-important region.

Aims Schoenoplectiella triangulata is an emergent plant species widely used in wetland vegetation restoration. It is important to study the germination and dormancy characteristics of S. triangulata seeds from different populations for germplasm collection and scientific utilization.

Methods In this study, differences in the morphological characteristics and germination characteristics of S. triangulata seeds were investigated, and the mechanisms of seed dormancy were explored.

Important findings (1) The seeds of S. triangulata showed physiological dormancy (PD), and there were significant differences in morphology, PD, 1 000-grain mass and water absorption characteristics among populations. (2) Light and variable temperature were conducive to seed germination of S. triangulata.(3) Sand storage at low temperatures, water storage at low temperatures and sand storage at normal temperatures helped to break the dormancy of S. triangulata seeds. Both fluridone and gibberellin treatments also helped to break the dormancy of S. triangulata seeds, but these effects varied among different populations. (4) Among different populations of S. triangulata, seed morphological characteristics, germination characteristics and dormancy characteristics were correlated with environmental conditions of the collection site. These results indicate that provenance should be considered when S. triangulata seeds were applied in wetland ecological restoration and that proper seed treatments before sowing could improve seed germination and the effectiveness of ecological restoration.

Aims Invasive Sphagneticola trilobataseriously endangers the stability of local plant communities and ecosystems. Recently, chemical control is still the most important method for controlling it. Arbuscular mycorrhizal fungi (AMF) play an important role in the growth of host plants and their resistance to environmental stresses. Therefore, this study tested whether AMF played an important role in herbicide resistance of S. trilobata.

Methods In this study, a greenhouse experiment was conducted, in which the stems of S. trilobata were subject to the following four treatments: control (CK), only inoculation of AMF, only application of herbicides (HC), and herbicide plus AMF (AMF + HC).

Important findings The results showed that under the stress of glyphosate ammonium salt, the colonization rate, vesicle number and ratio of colonization abundance class increased significantly. Compared with herbicide application, AMF inoculation significantly increased the leaf area, above-ground biomass and root shoot ratio of S. trilobata, and significantly reduced the flavonol relative content and the damaged leaf number. This study found that the herbicide stress on invasive S. trilobata was alleviated because of the symbiosis with AMF. Therefore, AMF may greatly improve the resistance to chemical herbicides in this invasive forb. The results of this study may provide a new insight into the effective control of invasive weeds.

Aims Arbuscular mycorrhizal fungi (AMF) are widely distributed in grassland ecosystems. They make great contribution to the productivity and stability of grassland ecosystems. Our purpose was to explore the AMF community distribution characteristics and driving mechanism in grassland ecosystems.

Methods This study was conducted in 18 different grassland types. We demonstrate the AMF community characteristics and driving factors by investigating plant community characteristics, analyzing soil physicochemical properties and AMF communities.

Important findings In different grassland types, the dominant genera of AMF community were Claroideoglomus, Septoglomus, Diversispora, Rhizophagus, Acaulospora, Glomus and Ambispora. In addition, there exist significant differences in speicies composition and diversity of AMF communities, and the AMF diversity and rare operational taxonomic unites (OTUs) in Stipa purpurea grassland was relatively higher than those of other grassland types. Results from the structural equation model showed that AMF community diversity was significantly influenced by plant community diversity and soil pH, and AMF community composition was significantly influenced by temperature, soil moisture content and plant community composition. To sum up, abundant AMF resources were contained within Chinese natural grassland, and the AMF community characteristics in different grassland types are significantly different. Meanwhile, plant communities have remarkable driving effect on AMF communities in grassland ecosystems. So protecting grassland plant diversity is of great importance for maintaining soil microbial community stability.