Functional traits play a vital role in mediating the responses of ecosystem services to environmental changes and in predicting functioning of ecosystem. However, the connection between functional traits and ecosystem services has become increasingly intricate due to climate change and human activities for degraded ecosystems. To investigate this relationship, we selected 27 sampling sites in the Yanhe River Basin of the Chinese Loess Plateau, each containing two types of vegetation ecosystems: natural vegetation and artificial vegetation ecosystem. At each sampling site, we measured ecosystem services and calculated the composition index of community traits. We established a response-effect trait framework that included environmental factors such as climate, elevation, and human activities. Our results showed that leaf tissue density (LTD) was the overlapping response and effect trait when responding to climate change. LTD is positively correlated with mean annual temperature and negatively correlated with supporting services. Under the influence of human activities, leaf nitrogen content (LNC) and leaf dry matter content (LDMC) were carriers of environmental change. Comparing the two vegetation ecosystems, the relationship between functional traits and ecosystem services showed divergent patterns, indicating that human activities increased the uncertainty of the relationship between functional traits and ecosystem services. Trait-based ecology holds promise for enhancing predictions of ecosystem services responses to environmental changes. However, the predictive ability is influenced by the complexity of environmental changes. In conclusion, our study highlights the importance of understanding the complex connection between functional traits and ecosystem services in response to climate changes and human activities.

The protection and management of the wetland should consider the changes in hydrological connectivity caused by the structural modifications of the soil macropores. The main purpose of our work is to clarify and quantify the influence of the soil macropores volume on vertical soil hydrodynamic process mechanically and statistically by taking the form of a case-study in Yellow River Delta (YRD), and further reveal the vertical hydrological connectivity in this area. Based on X-ray computed tomography (CT) and constant head permeability test, the results showed a highly spatial heterogeneity of the soil structure in the YRD, hydraulic parameter (Ks) was negatively correlated with bulk density (BD) and positively with soil macropore volume, soil aeration (SA), and maximum water capacity (MWC). Using Hydrus 1-D software and the Green-Ampt model, we estimated the characteristics of hydrodynamic process in the soil without macropores, then evaluated the effect of the soil macropore on soil hydrological connectivity by comparing the experimental results with the simulation results. We found that increasing soil microporosity improved the convenience of water movement, which would enhance the hydrological connectivity of the region. The results will further help to reveal the eco-hydrological process at vertical scale in soil and provide a theoretical guide for wetland conservation and restoration.

Leaf trichomes are derived from epidermal cells and serve an important function in regulating leaf heat balance and gas exchange. Variation in leaf functional traits is critical for predicting how plants will react to global climate change. In this study, we aimed to investigate how leaf trichome densities vary along large geographic gradients and how they interact with with stomata in response to environmental change. We investigated the leaf trichome densities of 44 Quercus variabilis populations in Eastern Asia (24° to 51.8° N, 99° to 137° E) and their correlation with climatic factors and stomatal traits. In addition, 15 populations were grown in a common garden to study their adaptive variation and coordination with stomata. The mean value of trichome density in situ conditions was 459.78 trichome mm^-2 with a range of 325.79 to 552.38 trichome mm^-2. Trichome density increased with latitude and decreased with longitude. Both temperature and precipitation reduced the trichome density. Moreover, trichome density was positively correlated with stomatal density whether in situ or in the common garden, and both increased with drought. Our results suggested that leaf trichomes possess highly adaptive variation and are in close coordination with stomata in response to climate change. Our findings provide new insights toward elucidating the interactions between leaf traits and the adaptive strategies of plants under climate change.

Hemisphere photos are now widely applied to provide information about solar radiation dynamics, canopy structure and their contribution to biophysical processes, plant productivity and ecosystem properties. The present study aims to improve the original “edge detection” method for binary classification between sky and canopy, which works not well for closed canopies. We supposed such inaccuracy probably is due to the influence of sky pixels on their neighbor canopy pixels. Here we introduced a new term “neighbor distance”, defined as the distance between pixels participated in the calculation of contrast at the edges between classified canopy and sky, into the “edge detection” method. We showed that choosing a suitable neighbor distance for a photo with specific gap fraction can significantly improve the accuracy of the original “edge detection” method. Combining the modified “edge detection” method and an iterative selection method, with the aid of an empirical power function for the relationship between neighbor distance and manually verified gap fraction, we developed a ND-IS (Neighbor Distance-Iteration Selection) method that can automatically determine the threshold values of hemisphere photos with high accuracy and reproductivity. This procedure worked well throughout a broad range of gap fraction (0.019 to 0.945) with different canopy composition and structure, in five forest biomes along a broad gradient of latitude and longitude across Eastern China. Our results highlight the necessity of integrating neighbor distance into the original “edge detection” algorithm. The advantages and limitations of the method, and the application of the method in the field were also discussed.

Natural wetland areas in China have experienced a continuous decline over the past two decades, which is partly due to the lack of comprehensive wetland protection laws and regulations. Despite investing over 4.24 billion USD in wetland conservation and restoration since 2000, the deterioration of wetlands persists. This study reviews the development of global wetland protection laws and regulations, analyzes the progress of wetland legislation in China, and explores the impact of economic development levels on wetland protection legislation, while also providing an in-depth interpretation of the core elements of the "Wetland Protection Law of the People's Republic of China." The results indicate that since the late 1940s, wetland protection laws and regulations have begun to emerge, with most developed countries gradually implementing related policies between the 1980s and 1990s; about 71% of wetland protection laws are concentrated in 29 countries, while 69 countries still lack specific wetland protection laws. An analysis of 962 global documents reveals that wetland protection legislation mainly focuses on the protection of water resources, species, and ecosystems. China's wetland legislation started late, with the "Wetland Protection Law of the People's Republic of China" being officially implemented only in June 2022. Furthermore, the study points out that economic development plays a crucial role in wetland legislation worldwide. Lastly, the article summarizes the key features of the "Wetland Protection Law of the People's Republic of China," including the improvement of the environmental protection legislative system, increased penalties for illegal occupation of wetlands, clearer protection goals, and the assurance of the integrity and connectivity of wetland ecosystems through stringent policies.

The biomass of wetland plants is highly responsive to environmental factors and plays a crucial role in the dynamics of the soil organic carbon (SOC) pool. In this study, we collected and analyzed global data on wetland plant biomass from 1980 to 2021. By examining 1134 observations from 182 published papers on wetland ecosystems, we created a comprehensive database of wetland plant above-ground biomass (AGB) and below-ground biomass (BGB). Using this database, we analyzed the biomass characteristics of different climate zones, wetland types, and plant species globally. Based on this, we analyzed the differences between the biomass of different plant species and the linkage between AGB and BGB and organic carbon. Our study has revealed that wetland plant AGB is greater in equatorial regions but BGB is highest in polar areas, and lowest in arid and equatorial zones. For plant species, BGB of the Poales is higher than the AGB but Caryophyllales, Cyperales, and Lamiales have higher AGB. Moreover, our findings indicate that BGB plays a more significant role in contributing to the organic carbon pool compared to AGB. Notably, when BGB is less than 1 (t C ha^-1), even slight changes in biomass can have a significant impact on the organic carbon pool. And we observed that the SOC increases by 5.7 t C ha^-1 when the BGB content is low, indicating that the SOC is more sensitive to changes in biomass under such circumstances. Our study provides a basis for the global response of above- and below-ground biomass of wetland plants to organic carbon.

Grazing exerts a profound influence on both the plant diversity and productivity of grasslands, while simultaneously exerting a significant impact on regulating grassland soil carbon sequestration. Moreover, besides altering the taxonomic diversity of plant communities, grazing can also affect their diversity of functional traits. However, we still poorly understand how grazing modifies the relationship between plant functional diversity and soil carbon sequestration in grassland ecosystems. Here we conducted a grazing manipulation experiment to investigate the effects of different grazing regimes (no grazing; sheep grazing; cattle grazing) on the relationships between plant functional diversity and soil carbon sequestration in meadow and desert steppe. Our findings showed that different livestock species changed the relationships between plant functional diversity and soil organic carbon (SOC) in the meadow steppe. Sheep grazing decoupled the originally positive relationship between functional diversity and SOC, whereas cattle grazing changed the relationship from positive to negative. In desert steppe both sheep and cattle grazing strengthened the positive relationship between functional diversity and SOC. Our study illuminates the considerable impact of livestock species on the intricate mechanisms of soil carbon sequestration, primarily mediated through the modulation of various measures of functional trait diversity. In ungrazed meadows and grazed deserts, maintaining high plant functional diversity is conducive to soil carbon sequestration, whereas in grazed meadows and ungrazed deserts, this relationship may disappear or even reverse. By measuring the traits and controlling the grazing activities, we can accurately predict the carbon sequestration potential in grassland ecosystems.

Direct sewage discharge may enhance soil nitrous oxide (N₂O) emissions, worsening the greenhouse effect. However, the effects of sewage discharge into bogs on N₂O flux, drivers, and influencing mechanisms remain unclear. Additionally, investigating the impact of reclaimed water on N₂O flux is important for bog replenishment and water shortage alleviation. This study simulated sewage from different sources into a bog and analyzed N₂O fluxes, soil (organic carbon, total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, available phosphorus, pH, and electrical conductivity), plant (species richness and biomass), and microorganisms (ammonia-oxidizing archaea, napA, nirS, nirK, and nosZ genes). Results showed that the reclaimed water did not significantly change N₂O flux, while 50% tap water mixed with 50% domestic sewage and domestic sewage significantly increased the N₂O flux. Among soil factors, available nitrogen and pH were key in influencing N₂O flux. Among plant parameters, species richness was the primary factor affecting N₂O flux. Nitrogen transformation functional genes contributed the most to the increase in the N₂O fluxes, with an increase in domestic sewage input leading to a higher abundance of these genes and subsequent N₂O emissions. Therefore, domestic sewage should be considered, as it significantly increases N₂O emissions by affecting the soil, plants, and microorganisms, thereby increasing the global warming potential. This study's findings suggest that using treated reclaimed water for bog replenishment could be an environmentally friendly approach to wetland management.

Rubber plantations have increased significantly under unprecedented economic growth in tropical areas, which leads to soil degradation and thereby alters soil hydrological processes. However, our understanding of how forest conversion affects soil hydrological processes remains unclear. Here, we collected soil samples from secondary forests (SF) and rubber plantations (RP) to determine the soil hydrological characteristics. We found the topsoil (0-20 cm) water retention in SF was higher than that of RP but displayed the contrast pattern in a deeper soil layer (20-60 cm). Meanwhile, the soil infiltration rates among two vegetation types decreased significantly with infiltration time, with higher stable soil infiltration rates in SF than those in RP. Moreover, soil properties were also impacted by the forest conversion, such as the topsoil capillary porosity and total porosity in SF were higher than those of RP but contrasted in a deep soil layer. In comparison, the topsoil bulk density in SF was lower than that of RP, but contrasted in the deep soil layer and reached a significant level in the 0-10 cm and 40-50 cm (P<0.05). Overall, the soil water retention was mainly determined by the capillary porosity, which could explain 31.56% of total variance in soil water retention, followed by total porosity (26.57%) and soil bulk density (26.47%), whereas soil texture exerts a week effect on soil water retention. Therefore, we can conclude that the conversion of tropical rainforest into rubber plantations may accelerate soil erosion owing to its lower soil water retention and soil infiltration rates.

Allelopathy plays an important role in the interaction between invasive and resident plants. Atmospheric nitrogen deposition has become a global problem, but it is unclear whether nitrogen affects the interaction between invasive and resident plants by affecting their allelopathy. Thus, we performed a greenhouse experiment in which the resident plant community was grown under two levels of invasion by S. canadensis (invasion vs. no invasion) and fully crossed with two levels of allelopathy (with or without adding activated carbon) and two levels of nitrogen addition (with or without). The resident plant communities were constructed with eight herbaceous species that often co-occur with S. canadensis. The research results show that both allelopathy of S. canadensis and the resident plants had obvious positive effects on their own growth. Nitrogen addition had more obvious positive effects on the resident plants under invasion than those that were not invaded. Moreover, nitrogen addition also altered the allelopathy of resident plants. Specifically, nitrogen addition improved the allelopathy of resident plants when they were invaded but decreased the allelopathy of resident plants when they grew alone. Although nitrogen addition had no obvious effect on S. canadensis, it reduced the allelopathy of S. canadensis. These results show that nitrogen addition could improve the resistance of resident plants to invasion by improving the allelopathy of resident plants and reducing the allelopathy of S. canadensis. The results of this study provide a scientific basis to manage and control the S. canadensis invasion.

Although the effects of arbuscular mycorrhizal fungi (AMF) on host plants have been well documented, whether the effects of AMF on parental generations could affect offspring performance is not fully clear. We conducted a common garden experiment to determine whether AMF status of host plants (Medicago truncatula) affect phenotype and transcriptome expression of their offspring. Seeds from four type parental treatments (low- phosphorus (P) soil without AMF, low-P soil with AMF, high-P soil without AMF and high-P soil with AMF were grown under low-P (LPS) and normal-P soil (OHS) conditions. The flowering pattern of LP offspring was similar to their parents that plants with AMF flowered earlier than those without AMF under OHS condition but was opposite under LPS condition. The transcriptome differential analysis showed that some differential transcripts (45 for parental plants growing under low-P condition and 3 for parental plants growing under high-P condition) expression patterns between offspring were similar, and only affected by parental AMF status regardless of the P environment that offspring grew. Others (146 for parental plants growing under low-P condition and 2 for parental plants growing under high-P condition), however, were affected both by the parental AMF status and the offspring P environment. Meanwhile, the number of differential transcripts between offspring whose parental plants grew under high-P condition were far less than under low-P condition. These results indicate that AMF may not only affect the current generation of host plants but also affect the offspring especially when their parents have experienced a stressful environment.