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Abstract The global wastewater surge demands constructed wetlands (CWs) to achieve the UN’s Sustainable Development Goals (SDG); yet the pollutant removal interactions and global sustainability of small CWs are unclear. This study synthesizes small CW data from 364 sites worldwide. The removal efficiency of organic matter and nutrient pollutants of small CWs had a 75th percentile of 68.8–84.0%. Bivariate analysis found consistent synergies between pollutant removals, lasting 3–12 years. The optimal thresholds for maintaining the synergistic effects were as follows: area size—17587 m2, hydraulic loading rate—0.45 m/d, hydraulic retention time—8.2 days, and temperature—20.2 °C. When considering the co-benefits and sustainability of small CWs for multi-pollutants control, promoting small-scale CWs could be an effective and sustainable solution for managing diverse wastewater pollutants while simultaneously minimizing land requirements. This solution holds the potential to address the challenges posed by global water scarcity resulting from wastewater discharge and water pollution.

Abstract Planting has been widely adopted to battle the loss of salt marshes and to establish living shorelines. However, the drivers of success in salt marsh planting and their ecological effects are poorly understood at the global scale. Here, we assemble a global database, encompassing 22,074 observations reported in 210 studies, to examine the drivers and impacts of salt marsh planting. We show that, on average, 53% of plantings survived globally, and plant survival and growth can be enhanced by careful design of sites, species selection, and novel planted technologies. Planting enhances shoreline protection, primary productivity, soil carbon storage, biodiversity conservation and fishery production (effect sizes = 0.61, 1.55, 0.21, 0.10 and 1.01, respectively), compared with degraded wetlands. However, the ecosystem services of planted marshes, except for shoreline protection, have not yet fully recovered compared with natural wetlands (effect size = −0.25, 95% CI −0.29, −0.22). Fortunately, the levels of most ecological functions related to climate change mitigation and biodiversity increase with plantation age when compared with natural wetlands, and achieve equivalence to natural wetlands after 5–25 years. Overall, our results suggest that salt marsh planting could be used as a strategy to enhance shoreline protection, biodiversity conservation and carbon sequestration.

As part of mangrove restoration initiatives eco-friendly fence has been implemented in eroded coastal areas in recent years. These fences provide the capacity to mitigate incoming wave energy and facilitate sediment deposition, thereby promoting the establishment and maintenance of mangrove habitats. Nevertheless, it is crucial to investigate the influence of the infill porosity on the wave dissipation performance of these fences, as the infill porosity can vary considerably across different restoration projects. The aim of this research is to explore the relationship between the infill porosity and wave dissipation effectiveness to identify more efficient designs for these eco-friendly restoration measures. The experiments involving wave interactions with fence models were conducted in a wave flume measuring 0.8 m in width and 25 m in length. Four wooden fences with distinct infill porosities ranging from 0.60 to 0.90 were strategically positioned to assess wave transmission, reflection, and dissipation phenomena under 18 distinct wave conditions. Additionally, the simulating waves till shore (SWASH)model was employed to calibrate critical bulk drag coefficient parameters and simulate the flow velocity distribution surrounding the fences under the experimental wave conditions. The findings indicated that a fence with a reduced infill porosity exhibits a higher wave transmission coefficient. However, this is accompanied by a higher reflection coefficient and lower wave energy dissipation within the fence. Both the infill porosity and incident wave conditions influence the flow velocity distribution characteristics in the vicinity of the fences. The area where the interaction between waves and fences is the most prominent is concentrated in the upper water layer immediately adjacent to the frontal section of the fences. Understanding the velocity distribution and hydrodynamic characteristics of the fence area aids in better determining the suitable porosity of fill materials for engineering applications.

The ecological quality of river basins is significantly influenced by the complex network of river structures and their connectivity. This study measured the temporal and spatial variability of ecological quality, as reflected by remote sensing ecological indices (RSEI), and examined their responses to river network connectivity (RNC). In total, 8 RNC indices, including river structure of river density (Dr), water surface ratio (Wr), edge-node ratio (β), and network connectivity (γ), and node importance indices of betweenness centrality (BC), PageRank (PG_R), out_degree centrality (Out_D), and in_closeness centrality (In_C), were generated at the subbasin scale. Our results highlighted the significance of RNC in influencing both the values and variability of RSEI, and the extent of this influence varied across different time periods. Specifically, three distinct clusters can be extracted from the temporal variability of RSEI, representing wet, near-normal, and dry years. The river structure index of γ significantly influenced the spatial patterns of subbasin RSEIs, particularly in wet years (R2 = 0.554), whereas β displayed a pronounced U-shape correlation with subbasin RSEIs in dry years (R2 = 0.512). Although node importance indices did not correlate directly with subbasin RSEI levels, as the river structure indices did, they significantly positively affected temporal variability of subbasin RSEIs (EI_SD_t). Higher values of PG_R, Out_D, and In_C were associated with increased subbasin RSEI variability. Based on these correlations, we developed RNC-based RSEI and EI_SD_t models with high adjusted coefficients of determination to facilitate the assessment of ecosystem quality. This study provides essential insights into ecosystem dynamics related to river connectivity within a basin and offers valuable guidance for effective watershed management and conservation efforts aimed at enhancing ecological resilience and sustainability.

ABSTRACT The objective of this study was to identify differentially expressed genes (DEG) between females and males in early bovine embryos. Superovulated cattle (n = 4) in the age span of 16–18 months were artificially inseminated with semen from the same bull that has been proven to be fertile. Blastocysts were collected by routine non-surgical uterine flushing on day 7 after insemination. This study determines the sex of embryos using a micro-injection pipette to collect a few blastomeres through the Zona pellucida. The remaining blastomeres were used for single-cell RNA sequencing (scRNA-seq) analysis on the Illumina platform, followed by differential expression analysis, Gene Ontology (GO) function analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. The criteria for identifying DEG will be set at |log2(Fold change)| ≥ 1 and P

Phytoplankton community spatial scales vary in typical coastal bay-river systems under natural and anthropogenic effects. However, their relative importance in shaping phytoplankton spatial heterogeneity has been largely uncharacterized in the literature. In this study, we performed comprehensive analyses using field monitoring, meteorological, and remote sensing datasets from a coastal bay-river system in South China (the Guangdong-Hong Kong-Macao Greater Bay-Pearl River tributaries) to examine phytoplankton spatial heterogeneity and main effects. We showed that water quality in the four water bodies of the typical coastal bay-river system in South China were relatively poor. Phytoplankton community abundance, taxonomic grouping, dominant species, and species similarity varied significantly in response to environmental gradients. We showed that Cyanophyta, Bacillatiophyta, and Chlorophyta were dominant phyla, and we observed regional variations in taxonomic groups and dominant species. Phytoplankton abundance was significantly higher in Dongjiang River and water bodies in branched bays when compared with other regions due to nutrient input from extensive agricultural and urban development, where the dominant phylum was Cyanophyta. Cyclotella (Bacillariophyta) had relatively high abundance and was widely distributed throughout the coastal bay-river system, except in the Dongjiang River. Melosira (Bacillariophyta) had relatively high abundance in Dongjiang and Xijiang Rivers, Merismopedia (Cyanophyta) dominated in the Dongjiang River and highly urbanized branched bay areas, while Microcystis (Cyanophyta) only dominated in Beijiang and Xijiang Rivers. Dominant species distributions showed apparent spatial heterogeneity in phytoplankton community composition. Species similarities between different water bodies were generally low, but phytoplankton species similarities between the Dongjiang River and water bodies in the branched bay area were relatively high, which indicated that water exchange associated with freshwater and nutrient inputs may have profoundly influenced species dispersal and dominant phytoplankton species. Redundancy analyses (RDA) demonstrated that pH, elevation, photosynthetically active radiation (PAR), dissolved active phosphorus (SRP), total dissolved phosphorus (TP), total nitrogen (TN), and nitrate nitrogen (NO3−-N) values - associated with nutrient and climate indicators were the main factors explaining structured phytoplankton spatial distributions. Variance partitioning analyses (VPA) showed that phytoplankton community variations were explained by anthropogenic factors (eutrophication) in summer. Our study improves our understanding of the natural and anthropogenic effects on phytoplankton spatial heterogeneity and provides basic study data for long-term phytoplankton evolution from river to bay areas.

The Pearl River basin (PRB) is an important producing area and the gene pool of wild resources of Four Major Chinese carps (FMCC). However human activities and climate changes causes the area shrink of the river network in PRB, the pollution aggregation, the serious habitat destroy of aquatic organisms, and the threat of biological resources and their living environment. Based on the accurate location and distribution data of FMCC from the literature and the field survey report of 2015–2016, this study used the MaxEnt model to predict the hot spot distribution area of FMCC in PRB. The simulation results show that the distribution of FMCC in the PRB gradually increases from the upper reaches to the middle and lower reaches. According to the MaxEnt model, the hot spots of FMCC in the PRB are mainly distributed in the south reaches and the lower reaches of the southeast. The model simulation also demonstrates that the hottest spots for the distribution of FMCC species in the PRB are the Yujiang basin, the Qianjiang basin and the lower reaches of the Xijiang basin. This study can provide the scientific guidance for the protection and the restoration of FMCC species in the PRB.

The spin Hall effect (SHE), typically emerging in non-magnetic metals with strong spin-orbit couplings, has attracted significant attention for its ability to convert a charge current into a spin current, a key feature in power-efficient spintronic devices. Recently, an enhanced SHE has been detected in the magnetic alloys, where the spin Hall conductivity is strongly modified by the dynamical and thermal spin fluctuations. We find that the spin Hall angle ( ${\theta _{{\text{SH}}}}$ ) in Pt _100− _x Co _x alloys dramatically changes at the Curie temperature, which is positive in the paramagnetic phase akin to Pt, while negative in the ferromagnetic phase. Such intriguing behavior of ${\theta _{{\text{SH}}}}$ stemming from individual and collective fluctuations in the magnetic moments is further substantiated with the full-fledged Monte Carlo simulations. Our work broadens insights into the SHE and highlights the importance of spin fluctuations for the spin-current generation near the ferromagnetic instability point of magnetic alloys.

Soil heavy metal(loid)s contamination caused by rapid urbanization and industrialization seriously affects human health and hinders the global sustainable development goals (SDGs). Currently, there is a lack of comprehensive human health risk assessment (HHRA) studies for multiple land use types at the regional scale. We propose a practical risk assessment framework that integrates empirical Bayesian kriging (EBK), pollution level analyses, and modified HHRA modeling. The concentrations of copper industry-related metals (Cu, Ni, Cd, As, and Hg) in 332 topsoil samples from the south bank of the Yangtze River in Tongling were investigated. Obvious enrichment of Cu, Cd, As, and Hg was detected, and the average concentration of Cu was 5.24 times higher than the background values. The distribution of heavy metal(loid) pollution was typically high in the south and east, and low in the north and west. The mean errors of interpolation for Cu, Ni, and Hg were 0.84, 1.29, and 0, respectively, and the root mean square errors of interpolation for Cd and As were 1.29 and 0.86, respectively. Non-carcinogenic risks of soil heavy metal(loid)s were assessed as acceptable throughout the studied area. The hazard index decreased in the order As (0.448) > Ni (0.0729) > Cd (0.0136) > Hg (9.04 ×10−4) > Cu (6.41 ×10−4). Nevertheless, the carcinogenic risks of Ni, Cd, and As in 70–80% of the administrative units (AUs) were between 10−6 to 10−4, considered an unacceptable level. Exposure through the oral ingestion route accounted for 88.0–99.2% of the total three exposure routes. It is worth noting that four AUs were considered to be the priority control units, and Ni and As were identified as the priority control soil heavy metal(loid)s. This case demonstrates the feasibility and scientific validity of the new EBK-HHRA framework, which confirms that EBK can effectively predict the spatial distribution patterns of soil heavy metal(loid)s and that modified HHRA models are conducive to risk integration at the regional scale. The EBK-HHRA approach is generic and provides substantial support for risk source identification and risk management of soil heavy metal(loid)s contamination at the regional scale.

Deltas are in a dynamic balance due to the impact of fluvial and coastal flooding, and hydrological connectivity plays an important role. In recent decades, the dynamic equilibrium has been influenced by upstream and local human activities, including sea reclamation activities. However, in most instances, the influence of human activities has not been explicitly distinguished and quantified in detail. In this paper, the influence of sea reclamation activities on hydrological connectivity in the Yellow River Delta was quantified by parameterizing the resistance surfaces (a spatial layer that assigns a value to each landscape feature, indicating the degree to which that variable impedes or promotes movement) that includes sea reclamation activities. By optimizing a functional relationship between landscape features and hydrological connectivity (water flow movement patterns), the values in the resistance surfaces could be assigned. We first calculated hydrological distances among bifurcations from 1985 to 2020 with a 5-year interval representing the hydrological connectivity of each tidal creek. The sea reclamation activities in the YRD were classified into four: reclaimed land, sea enclosure activity, freshwater resource facilities, and engineering in the oil field to create resistance surfaces. We identified that the periods of 1990–1995 and 2000–2005 were under the most severe influence of sea reclamation activities. Sea enclosure activity, freshwater resource facilities, and engineering in oil fields played major roles in composing resistance surfaces. Mariculture (quantified relative resistance value, 1.00), reservoir (0.92), agriculture (0.91), and river (0.97) were the features with the highest resistance values in the initial and mature development stages. The formation of resistance (costs to movement) was due to human activities and natural factors, for example, the evolution of tidal creeks. To develop the resource in tidal flats sustainably, systematic monitoring and sufficient conservation awareness were required. This study contributed to coastal management and planning by providing a quantified assessment of different types of sea reclamation activities.

By offering natural protection along offshore wetlands, mangroves play a crucial role in providing great ecological and economic benefits to local communities. However, mangroves are currently facing an increasing threat of decline worldwide due to widespread human activities and climate change. Recently, eco-friendly wooden fences have been deployed along eroded coasts for mangrove restoration projects, and these fences have the capability to attenuate incoming waves and strengthen sediment deposition in new habitats for mangrove colonization and persistence. However, the design and performance of the fences used can differ substantially among different projects; therefore, it is necessary to study the major factors affecting the wave dissipation performance of these fences and find out a more effective structural design. Thus, we focus on two distinct types of fences with and without porous infill to study the function of infill porosity and frame density, and physical experiments of waves transmission through the fences were carried out in a wave flume, in which nine wooden fences with varied infill porosities (0.60–0.90) and frame densities (0.40 and 0.70) were predetermined to measure the wave transmission, reflection, and wave dissipation. In total, 180 experimental runs were conducted under 18 wave conditions with different wave steepness. The results showed that the fence with a lower infill porosity appears to increase wave transmission coefficient that comes at a cost of a higher reflection coefficient and less wave-energy dissipation inside the fence, and the fence with the highest porosity infills (90%) is nearly equivalent to the fence without any infills but a dense frame in terms of wave damping performance. Moreover, the wave transmission through both fences with and without infill can be remarkably affected by incoming wave steepness. The outcome of the research is not only indicating the importance of the appropriate infill porosity in attenuating incoming waves but also guiding the design of mangrove restoration project in offshore wetlands.

Spin–orbit torques (SOTs) provide an efficient way to electrically manipulate the magnetic order in spintronic devices. Compared with conventional ferromagnetic materials, ferrimagnetic materials have the advantages of antiferromagnetically coupled sublattices and induced ultrafast spin dynamics. In this paper, we study the current-induced magnetization switching in the ferrimagnetic Ta/GdFeCo/MgO system. Robust SOT-induced magnetization switching can be achieved at the magnetic compensation temperature point of around 70 K, where the magnetization is nearly zero and the coercivity can reach almost 3 T. The temperature dependence of the SOT efficiency is quantified by the second harmonic method, and the enhanced SOT efficiency near the magnetic compensation temperature is attributed to the negative exchange coupling between the two sublattices of CoFe and Gd. This work demonstrates the SOT switching of the nearly compensated ferrimagnet, with great potential for future magnetic interaction-free and ultrafast ferrimagnetic applications.

IntroductionRecently, accelerated sea-level rise (SLR) has raised major concerns on estuarine management and restoration because it modifies estuarine hydrodynamics, such as tidal inundation extent and amplitude, tidal current asymmetry, flood frequency, etc. Understanding underlying processes which regulate estuarine tidal dynamics is critical for mitigating potential impacts on the coastal population and development.MethodsWe selected the Pearl River Estuary (PRE), an estuary with a higher regional SLR compared to the global SLR as the study area. To identify the effects of regional SLR on tidal dynamics, we analyzed long-term records of four tidal variables from 19 gauge stations between 1952 and 2020, including annual highest tidal levels (AHTLs), annual lowest tidal levels (ALTLs), annual mean tidal ranges (AMTRs), and annual mean tidal levels (AMTLs).ResultsResults suggested that variability in tidal variables was site-specific. The AMTRs decreased gradually from offshore regions to the upper reaches of rivers with a maximum at the mouth of the estuary. In contrast, the magnitudes of the AHTLs, AMTLs, and ALTLs decreased when approaching the coastline. Distance to the coastline had the highest correlations with the AHTLs, ALTLs, and AMTLs, followed by river width and river depth. The local SLR was responsible for the temporal variability in AHTLs, ALTLs, and AMTLs at the estuarine mouth with correlation coefficients from 0.43 to 0.85 (P < 0.001) but showed low correlations with these three tidal variables at the upper reaches of rivers (P > 0.001). Instead, the tidal variables were highly correlated with river discharge at the upper reaches of rivers, especially for the AHTLs (correlation coefficient = 0.83, P < 0.0001).ConclusionsOur study demonstrated that the tidal dynamics demonstrate significant spatial-temporal variability. Geomorphology, river discharge, and sea levels have jointly affected estuarine hydrodynamics.

High-strength alterations in the water level due to extreme climate change and increased anthropogenic activities have implications for methane (CH4) and carbon dioxide (CO2) emission variations in shallow lakes. However, the consistency of the carbon emission flux in response to water-level fluctuations and temperature is still unclear. Here, we evaluated the water depth (WD) on the magnitude and variation sensitivity of CH4, CO2, and GHG, and then the temperature dependence of carbon emissions was estimated at different water levels. The water depth threshold indicated a maximum CH4 (97.5 cm) and CO2 (10 cm), resulting in a water depth threshold of GHG at 54.6 cm. Inside the whole WD, the effect of rising water depth on CH4, CO2 and GHG sensitivity shifted from a positive effect to a negative effect at a WD of 97.5 cm. And CH4, CO2 and GHG in 10 cm

We explored the potential for functional processes maintenance principles to be applied in coastal restoration. Greater bay areas are located in the transition zone between land and sea. Coastal wetlands play a key role in the ecological environment construction of greater bay areas. Due to the dual effects of high-intensity human activities and climate change, coastal wetlands in greater bay areas have suffered varying degrees of damage, including reduced area, habitat degradation, and impaired ecological functions. However, the research progress and development trend of restoration of damaged coastal wetland ecosystems has not yet been revealed, and the application theory of functional processes in coastal restoration is still unclear. Based on extensive literature research, our study reviewed the mechanisms and types of coastal wetland ecosystem restoration in greater bay areas. Coastal wetland ecosystem restoration technologies and methods are mainly based on the biological, hydrological, and chemical processes in greater bay areas. The current research progress and existing deficiencies of coastal wetland ecosystem restoration in greater bay areas are clarified. Combining years of research background in the coastal wetland field, focusing on the importance and criticality of coastal wetland functional processes to maintaining ecosystem functions, the main future research trends are proposed, which will solve the principal theory facing the restoration of coastal wetland ecosystems in greater bay areas. Our study will promote the application of new concepts and new techniques of coastal wetland restoration nationwide, and improve the overall level of ecological restoration in coastal wetland.

Crabs are the most dominant groups in mangrove ecosystem and play a vital role in building and sustaining the structure and function of the mangrove ecosystems. However, a systematic evaluation of global research status of mangrove crabs is still lacking. Here, a bibliometric analysis based on the Science Citation Index Expanded (SCI-E) was carried out to provide insights into research activities, tendencies, and challenges of the mangrove crabs from 1980 to 2016. The results showed that the average annual output of the publications was low. Brazil took a leading position out of the 63 countries/territories with the largest number of publications, followed by USA, Australia, China, and Germany. Journal of Experimental Marine Biology and Ecology was the most popular journal. The reproductive ecology (e.g., reproduction), population ecology (e.g., population structure), and their relationship were the mainstream. The estuarine ecosystem and the method of stable isotope received ecologists’ favor. Behavioral ecology (e.g., bioturbation), ecosystem function (e.g., carbon), and the ecological effect among them were the main issues in this field. Biodiversity was a new hot topic. Brazil, Australia, USA, China, and Kenya were the top five hot regions among the 53 hot countries on a global scale. Different regions have different hot topics. The breeding ecology was the most popular theme in the Americas region, the ecological effects of crabs were the most hotstops in the Africa-East Asia region and the East and South Asia-Oceania region. The challenges of the development were not comprehensive and uneven on a global scale. There was a certain number of countries with mangrove distributions were still outside this field, such as most of the western and northeastern countries of Africa (e.g., Angola), some Central American countries (e.g., Guatemala), and some western and southeast Asian countries (e.g., Cambodia). Furthermore, we found that some topics were ignored or lagged in each territory. Our results highlight that the global research status of mangrove crab is still at a relatively backward stage, and regional development is extremely unbalanced.

The water discharge and sediment load have been increasingly altered by climate change and human activities in recent decades. For the Pearl River, however, long-term variations in the sediment regime, especially in the last decade, remain poorly known. Here we updated knowledge of the temporal trends in the sediment regime of the Pearl River at annual, seasonal and monthly time scales from the 1950s to 2020. Results show that the annual sediment load and suspended sediment concentration (SSC) exhibited drastically decreased, regardless of water discharge. Compared with previous studies, we also found that sediment load and SSC reached a conspicuous peak in the 1980s, and showed a significant decline starting in the 2000s and 1990s, respectively. In the last decade, however, water discharge and sediment load showed slightly increasing trends. At the seasonal scale, the wet-season water discharge displays a decreasing trend, while the dry-season water discharge is increasing. At the monthly scale, the flood seasons in the North and East Rivers typically occur one month earlier than that in the West River due to the different precipitation regimes. Precipitation was responsible for the long-term change of discharge, while human activities (e.g. dam construction and land use change) exerted different effects on the variations in sediment load among different periods. Changes in the sediment regime have exerted substantial influences on downstream channel morphology and saltwater intrusion in the Greater Bay Area. Our study proposes a watershed-based solution, and provides scientific guidelines for the sustainable development of the Greater Bay Area.

Human activities have profoundly affected coastal wetlands. Apart from direct occupation, indirect influences are usually caused by modifications to environmental conditions, which are various and complex. Saltmarsh bare patches might be related to these artificial modifications. They have little or no vegetation cover and lose some important functions. Hence, the mechanisms underlying saltmarsh bare patches and the effects of artificial modifications should be studied. We took the Yellow River Delta as our research object and explored the characteristics of saltmarsh bare patches in the Yellow River Estuary Natural Reserve. Our results show that artificial modifications limit some key plant life stages and thus hinder the natural regeneration process. Once suffering from fatal events, such as long-term inundation or artificial damage, this limitation will lead to the formation of persistent bare patches in saltmarshes. First, a shortage of local seed sources will be induced by the death of local plants when they are affected by a fatal event. Second, the replenishment of external seeds is often constrained by dikes and dams. Third, construction activities and the prolonged high-water inundation events can lead to soil compaction and the lack of microtopographic heterogeneity, which will hinder the retention and anchorage of seeds. Overall, it is essential to realize the underlying mechanisms of persistent bare patches and their potential to be included in cost-effective restoration or management plans.

Burrowing crabs are widely distributed and have large populations in estuarine wetlands. Crab excavation can have potentially significant bioturbation effects on the vertical structure of sediments, and the processes of nutrients deposition and mineralization. However, the effects of crab micro activities on the geochemical cycling processes of the whole estuarine ecosystems are not clear, specifically the contributions of burrowing crabs to sediment and nutrients turnover in coastal ecosystems. Due to the lack of knowledge on crab burrowing behavior and borrow morphology, it is difficult to accurately estimate the excavation and turnover volumes of crabs. Therefore, this study examined the bioturbation activity of the crab Helice tientsinensis in western Pacific estuary ecosystems by analyzing their burrow morphology and local sediment properties. The common burrow shapes of Helice tientsinensis were J- and Y-shaped burrows. Burrow morphological characteristics such as total burrow depth, curve burrow length, burrow volume, and opening diameter significantly differed among tidal zones. Crab carapace size, water depth, soil hardness, and bulk density were the main factors driving burrow morphology. Sediment excavation by crabs was ~50 times greater than the deposition of sediment into crab burrows. The net transported amounts of sediment (31.66–33.18 g·d-1·m-2) and nutrients (total nitrogen: 0.075–0.090 g·d-1·m-2, total carbon: 3.96–4.55 g·d-1·m-2, and organic matter: 0.44–0.77 g·d-1·m-2) were mainly from the belowground sediment to the surface. These results highlighted the important role of crabs in sediment and nutrients cycling within coastal estuary ecosystems.

Coastal wetlands serve as sources and sinks of carbon, nitrogen, phosphorus, and sulfur, and their ecological stoichiometry intuitively indicates the biogeochemical cycle process of the region. This study investigated the changing trend of the contents of soil organic carbon (i.e., SOC), total nitrogen (i.e., TN), total phosphorus (i.e., TP), and total sulfur (i.e., TS) and their ecological stoichiometric ratios in 2019-2021 in the Yellow River Delta (including north and south banks) under the Internationally Important Wetland Biodiversity Conservation Project by conducting field surveys and experiments. The results showed that SOC, TN, and TP showed the highest content in the North Unrestoration, while the TS content appeared highest in the North Restoration. In addition, ecological restoration improved the biogenic element stability in both banks and improved the stability of ecological stoichiometry on the north bank while decreasing the ecological stoichiometry stability on the south bank. Notably, the changing trend of soil C/S in the North Unrestoration exhibited a considerably different profile similarity from the North Restoration, which indicates that the ecological restoration changed the wetland ecosystem from the perspective of soil C/S. Furthermore, the high content of soil biogenic elements SOC and high ratio of soil ecological stoichiometry C/N and C/S in the Yellow River Delta induce that they are more sensitive to environmental change. Over the three years, the contributions of soil moisture content, soil salinity, and pH to soil biogenic element contents and their stoichiometric ratios were 32.20%, 49.30%, and 18.50% on the north bank, respectively, and 85.70%, 8.50%, and 5.80% on the south bank, respectively. This study implies that ecological restoration generally has a positive effect on the soil biogenic element contents and their ecological stoichiometry in the Yellow River Delta and provides a reference for delta restoration.

As an aggressive invasive salt marsh plant, Spartina alterniflora has been found to invade along tidal channel networks and threaten native salt marsh ecosystems. Previous studies have established patterning correlations between S. alterniflora invasion and tidal channel functions (drainage efficiency). However, a systematic analysis of S. alterniflora invasion in relation to functional and geometric features of tidal channel networks is still lacking. In this study, we extracted tidal channel networks from remote sensing images of the Yellow River Delta, China, and performed numerical experiments to examine S. alterniflora invasion patterns with tidal channel networks with varying drainage efficiency and geometric nuances. An existing vegetation dynamics model was adapted to incorporate hydrochorous seed dispersal and salinity buffer zone as the primary mechanisms of tidal channels to facilitate vegetation colonization and was further coupled with Delft3D. We analyzed the correlation of the simulated S. alterniflora area with a comprehensive set of tidal channel functional and geometric metrics across different spatial scales. Our results confirmed that watersheds with higher drainage efficiency (larger tidal channel density (TCD) and geometric efficiency (GE), smaller overmarsh path length (OPL)) attained larger S. alterniflora area. Given a similar drainage efficiency, tidal channel networks with greater geometric mean bifurcation ratio enhanced S. alterniflora invasion. On a local scale, channel order dictated local drainage efficiency (spatially-varying TCDo) and further influenced S. alterniflora area. The observed patterns were further verified in principle by two real cases in the Yellow River Delta. Finally, in viewing the efficacy of all metrics tested and further considering their computational costs, we proposed a holistic metric framework consisting of global metrics including TCD and geometric mean bifurcation ratio and local metric including spatially-varying TCDo, to assess how tidal channel network mediates S. alterniflora invasion in particular and salt marsh vegetation expansion in general in marsh-channel systems.

Black-necked crane (Grus nigricollis, BNC), facing serious threats from human activities and habitat variations, is an endangered species classified as vulnerable under the revised IUCN Red List. In this article, we investigated and analyzed the population and nesting microhabitat of BNCs in the Longbao National Nature Reserve (NNR) from 1978 to 2016, and found the number of BNCs increased from 24 in 1978 to 216 in 2016. This establishment of the Longbao NNR represented the activities of protecting endangered animal species are effective. However, the land cover classification results of Landsat images showed that the marsh wetland, which was the BNC’s primary habitat, decreased during 1978–2016, while artificial buildings increased, which affected the habitat of BNCs. The increase in average temperature over the past 40 years has also had an impact on the number of BNCs. BNCs preferred to nest in marsh wetlands or on islands with open water or star-like distributions through observation. The results of the principal component analysis showed that the nearest distance between nests and habitat type were the primary factors influencing nesting site selection. To protect BNC, we suggest decreasing wetland fragmentation, reducing habitat degradation and providing an undisturbed habitat.

River deltas are formed by the interaction of connecting water and sediment, and they are among the most economically and ecologically valuable ecosystems on Earth. Because of their special locations, together with direct and indirect human interference, river deltas are expected to be more vulnerable and fragmented. The increasing fragmentation of deltas is largely due to longitudinal hydrological connectivity disruption caused by human activities. However, the dynamics of longitudinal connectivity are unknown, especially in the Yellow River Delta (YRD), which has been subjected to heavy reclamation in recent years. In this study, we divided the whole YRD into three subregions, the erosion zone, the oilfield zone and the deposition zone, and then we used indicators to explore the spatiotemporal variation in hydrological connectivity on the whole scale and on the zonal scale of the delta during 1984-2018 in the YRD. We found that the variation in longitudinal hydrological connectivity was closely related to the geometry of the tidal channel networks, and that the changes in longitudinal hydrological connectivity varied with research scales. A weak increasing trend of connectivity was found on the whole scale of the delta during the past three decades. A decreasing trend of connectivity was found in both the erosion zone and the oilfield zone. In the deposition zone, however, the connectivity degree was enhanced. Furthermore, we also identified the key impaired area and relatively stable area of hydrological connectivity in the YRD and implied that the key impaired area may be a priority restoration zone of the impaired hydrological connectivity zone. Our study provides useful scientific guidance for the subsequent restoration of damaged wetlands.

Owing to climate warming and human activities (irrigation and reservoirs), sea level rise and runoff reduction have been threatening the coastal ecosystem by increasing the soil salinity. However, short-term sparse in situ observations limit the study on the response of coastal soil salinity to external stressors and thus its effect on coastal ecosystem. In this study, based on hydrological connectivity metric and random forest algorithm (RF), we develop a coastal soil salinity inversion model with in situ observations and satellite-based datasets. Using Landsat images and ancillary as input variables, we produce a 30-m monthly grid dataset of surface soil salinity over the Yellow River Delta. Based on the cross-validation result with in situ observations, the proposed RF model performs higher accuracy and stability with determination coefficient of 0.89, root mean square error of 1.48 g·kg-1, and mean absolute error of 1.05 g·kg-1. The proposed RF model can gain the accuracy improvements of about 11–43% over previous models at different conditions. The spatial distribution and seasonal variabilities of soil salinity is sensitive to the changing signals of runoff, tide, and local precipitation. Combining spatiotemporal collaborative information with the hydrological connectivity metric, we found that the proposed RF model can accurately estimate surface soil salinity, especially in natural reserved regions. The modeling results of surface soil salinity can be significant for exploring the effect of seawater intrusion and runoff reduction to the evolution of coastal salt marsh ecosystems.

Thermokarst lakes are forming from permafrost thaw and are severely affected by accelerating climate change. Sediment and water in these lakes are distinct habitats but closely connected. However, our understanding of the differences and linkages between sediment and water in thermokarst lakes remains largely unknown, especially from the perspective of community assembly mechanisms. Here, we examined bacterial communities in sediment and water in thermokarst lakes in the Yellow River Source area, Qinghai-Tibet Plateau. Bacterial taxa were divided into abundant and rare according to their relative abundance, and the Sorensen dissimilarity (βsor) was partitioned into turnover (βturn) and nestedness (βnest). The whole bacterial communities and the abundant and rare subcommunities differed substantially between sediment and water in taxonomical composition, α-diversity, and β-diversity. Sediment had significantly lower α-diversity indexes but higher β-diversity than water. In general, bacterial communities are predominantly governed by strong turnover processes (βturn/βsor ratio of 0.925). Bacterial communities in sediment had a significantly higher βturn/βsor ratio than in water. Abundant subcommunities were significantly lower in the βturn/βsor ratio compared with rare subcommunities. The results suggest that the bacterial communities of thermokarst lakes, especially rare subcommunities or particularly in sediment, might be strongly structured by heterogeneity in the source material, environmental filtering, and geographical isolation, leading to compositionally distinct communities. This integral study increased our current knowledge of thermokarst lakes, enhancing our understanding of the community assembly rules and ecosystem structures and processes of these rapidly changing and vulnerable ecosystems.

While nutrient enrichment and herbivory have been well recognized as the main driving factors of seagrass meadow fragmentation and degradation, there is limited understanding of how their relative importance shifts across large spatial scales where environmental factors such as turbidity can vary. In this study, a field control experiment was conducted in two Zostera japonica meadows distributed on the two banks of the Yellow River Estuary with different turbidity, to investigate the combined effects of nutrient enrichment and herbivory on seagrass and macroalgae. Our results showed that turbidity had the mediating force of shifting the relative importance of nutrient enrichment and herbivory to seagrass and macroalgae. While herbivory played a vital role in maintaining the balance between the two primary producers in a turbid environment, nutrient enrichment tended to offset herbivory-induced biomass loss by promoting seagrass growth in a less turbid system. Additionally, two potential mechanisms that might regulate the responses of seagrasses and macroalgae to nutrient enrichment and herbivory under different turbidity are proposed. On the one hand, turbidity might mediate the feeding preference of herbivores. On the other hand, nutrient enrichment favors the growth of opportunistic macroalgae over seagrass in turbid systems. Our study emphasizes the mediating force of turbidity on seagrass ecosystems, and provides references for the protection and restoration of seagrass meadows under multiple environmental stressors, and prompts further studies on the feedback between sediment dynamics and seagrass meadows in the context of ecogeomorphology.

The responses of plant populations and communities to environmental factors play a key role in the ecological protection and restoration of lakes. However, little is known about how interspecific relationships respond to environmental gradients, especially for relationships between different growth forms such as submerged and emergent aquatic plants in shallow lakes, which can further affect species composition as community dynamics. We carried out a mesocosm experiment to investigate the responses of two focal aquatic plants (Ceratophyllum demersum and Phragmites australis) at two density levels and six levels of total nitrogen (TN) levels. Our results suggested that interspecific competition exist between C. demersum and P. australis, especially at high nitrogen levels. The competition relationship was mainly influenced by variations of relative growth rates of C. demersum and population density of P. australis along the nitrogen gradient. The interspecific neighbor effect on C. demersum shifted from facilitation to competition as TN increased, whereas on P. australis showed no significant facilitation effect along the TN gradient. Ceratophyllum demersum and P. australis adopted stress-tolerance and competition strategies for nitrogen, respectively, in co-culture. As a result, the dominant species in the plant community is likely to shift from the submerged macrophyte (C. demersum) to the emergent macrophyte (P. australis) as TN increases. Moderate TN (2.5 mg/L) can potentially support high biodiversity in macrophyte-dominated shallow lakes in our study. This finding has implications for different community composition at different nitrogen levels. Furthermore, it has important implications for protecting biodiversity and guiding vegetation restoration in shallow lakes.

The establishment of protected areas (PAs) is an effective and prevailing tool for conserving wetlands globally, however, strong evidence indicates that not all PAs can deliver adequate conservation to wetland ecosystems due to the impacts of natural and anthropogenic factors. Many studies have used multiple indices to assess the conservation effectiveness of PAs, but those complicated indices are usually difficult to be employed at large-scale. Therefore, this study aims to develop a rapid assessment methodology for conservation effectiveness of wetland PAs across the Chinese mainland. We combined the area and pattern-based landscape indices (i.e., Landuse Dynamic Index and Fragmentation Dynamic Index) to measure wetland landscape changes between 1990 and 2008, based on which we constructed the Area-Pattern Quadrant Analysis (APQA) system to facilitate the conservation assessment of wetland national nature reserves. Four typical modes of landscape changes were generalized to reveal and compare the conservation effectiveness associated with their cause-effect drivers among 92 wetland national nature reserves within ten major river basins across the Chinese mainland. In addition, 210 subcatchments containing the reserves were also used as baselines to assess and discriminate the natural and human-induced effects on the performance of those reserves. The areal percentages among the four modes indicated that the wetland landscape changes were dominated by spatially heterogeneous drivers, and reserves showed relatively low conservation effectiveness, particularly in those densely populated and socioeconomically developed regions such as the Yangtze River Basin, the Yellow River Basin and the Pearl River Basin. Only 16 reserves were excellently rated in conservation effectiveness, in comparison with 31 reserves poorly rated due to greater anthropogenic encroachment. Our research demonstrated that APQA-based landscape assessment can be used as an easily-used early warning indicator to capture wetland landscape changes in relation to their underlying natural and anthropogenic drivers, and to provide knowledge-based management guidance by using standardized and rapid assessment techniques.

Freshwater wetlands play an important role in preserving global biodiversity and substantial ecosystem services, but they are exposed to higher pressures and threats and have received less attention in conservation planning in comparison to terrestrial ecosystems. Although a number of freshwater protected areas have been established in China, considerable freshwater conservation gaps still exist where ecologically valuable freshwater wetlands are vulnerable to anthropogenic threats, our study therefore explored systematic conservation planning specifically suited to freshwater ecosystems for the large river basins in China. A scheme of Climatic-geomorphological Classification of Freshwater Ecosystems (CGCFEs) was developed and employed as broad-scale surrogates based on their unique ecohydrological processes and biodiversity assemblages. A freshwater conservation assessment was conducted for each river basin using a complementarity-based planning framework (i.e., systematic conservation planning) and the prioritization software Marxan in consideration of the conservation targets of CGCFEs. Our research also demonstrated the need to introduce the concept of incidental gaps (IGs) in freshwater conservation planning, where the focal species and ecosystems have unintentionally been incorporated into a nature reserve with different conservation targets and thus created “conservation gaps” due to incidental and unfocused conservation efforts. The identified complete gaps (CGs) and IGs accounted for 10.56% and 8.66% of the total freshwater area respectively, implicating the need to enhance freshwater conservation efficacy by realigning existing conservation patterns to address these gaps. Our research provides a spatially explicit freshwater conservation strategy at the river basin and national scales and thus enables the central government and wetland resource managers to set ecologically meaningful spatial conservation priorities for freshwater ecosystems within those major large river basins. In addition, the methodology of using CGCFEs can be replicated for large-scale freshwater conservation planning elsewhere and promote freshwater conservation efficiency by capturing irreplaceable freshwater habitats.

Thermokarst lakes are a ubiquitous and important landscape feature in cold regions and are changing tremendously due to the accelerated climate change. In thermokarst lakes, sediment and water are two distinct but highly interconnected habitats, harboring different bacterial communities in terms of taxonomic composition. However, the co-occurrence networks of these bacterial communities remain unclear. Here, we investigate the co-occurrence ecological networks of sediment and water bacterial communities for thermokarst lakes in the Yellow River Source Area on the Qinghai-Tibet Plateau. The results show that the bacterial communities construct distinct co-occurrence networks in sediment and water. The metacommunity network was parsed into four major modules formed by the operational taxonomic units (OTUs) enriched in sediment or water independently, and water-enriched OTUs exhibited much closer interconnections than sediment-enriched OTUs. When considering the sediment and water bacterial networks separately, different topological properties and modular patterns present: the sediment bacterial network was more clustered while the modules less responded to the environmental variables. On the contrary, the water bacterial network was more complex with the OTUs more interconnected and its modules more responded to the environmental variables. Moreover, the results of the structural equation model suggest that, by the influence of environmental variations on individual modules, the water bacterial communities would be more vulnerable under the fact of accelerating climate change. This study provides insights beyond a conventional taxonomic perspective, adding our knowledge of the potential mechanisms structuring bacterial community assembly and improving our prediction of the responses of this fast-changing ecosystem to future climate change.

Saltmarsh is a coastal ecosystem providing crucial ecosystem services, and its continued degradation and fragmentation has drawn increasing attention. However, how to effectively restore the connectivity between fragmented saltmarsh patches remains an open challenge. In this study, we developed a metric and modelling framework that prioritised saltmarsh patches for restoration. To demonstrate our approach, we simulated spatially explicit restoration schedules for Suaeda salsa patches at the Yellow River Delta National Nature Reserve, China, using three strategies: increasing-patch-area, increasing-number-of-patches and a benchmark unrestrictive prioritization strategy. We prioritised patches for restoration based on a number of widely used graph-theoretic landscape connectivity and metapopulation capacity metrics. Our simulation results suggested the rank connectivity-importance of extant patches was correlated within the group of graph-theoretic connectivity metrics or metapopulation capacity metrics, but unrelated across group. The unrestrictive prioritization strategy clearly outperformed the strategies of increasing-patch-area and increasing-number-of-patches which returned comparable connectivity restoration outcomes. For the more effective unrestrictive prioritization strategy, there were substantial differences in the simulated priority patches between metrics that considered stepping stone effects and those did not. While the former resulted in corridor-building priority patches that led to a more connected landscape throughout the region, the latter led to local clustering. We recommend use of the total probability of connectivity (PC) among the metrics we tested due to similarity of results to other metrics and its simulation efficiency. The proposed framework is readily applicable to prioritise areas for connectivity conservation and restoration in any monospecific ecosystem at the regional scale.

We report a current-induced four-state magnetization reversal under zero magnetic field in a wedged Ta/MgO/CoFeB/MgO heterostructure with a perpendicular magnetic anisotropy. Anomalous Hall effect and magneto-optical Kerr effect microscopy measurements were performed to demonstrate that the field-free multi-level reversal is jointly determined by the spin–orbit torque effective field that originates from the lack of the lateral inversion symmetry in the wedged stacking structure and the current-induced Oersted field. Moreover, the creation of robust intermediate Hall resistance states in the multi-state switching strongly depends on the current-induced Joule heating. Our results provide a route for the field-free multi-level state reversal, which is significant for fabricating the non-volatile and energy-efficient multi-level memories or artificial neuron devices.

The spin–orbit torques (SOTs) in the heavy metal (HM)/ferromagnetic metal (FM) structure hold promise for next-generation low-power and high-density spintronic memory and logic applications. For the SOT switching of a perpendicular magnetization, an external magnetic field is inevitable for breaking the mirror symmetry, which is not practical for high-density nanoelectronics applications. In this work, we study the current-induced field-free SOT switching and SOT perpendicular effective field (Hzeff) in a variety of laterally asymmetric multilayers, where the asymmetry is introduced by growing the FM layer in a wedge shape. We show that the design of structural asymmetry by wedging the FM layer is a universal scheme for realizing field-free SOT switching. Moreover, by comparing the FM layer thickness dependence of (Hzeff) in different samples, we show that the efficiency (β =Hzeff/J, J is the current density) is sensitive to the HM/FM interface and the FM layer thickness. The sign of β for thin FM thicknesses is related to the spin Hall angle (θSH) of the HM layer attached to the FM layer. β changes its sign with the thickness of the FM layer increasing, which may be caused by the thickness dependence of the work function of FM. These results show the possibility of engineering the deterministic field-free switching by combining the symmetry breaking and the materials design of the HM/FM interface.

Estimating the biomass of Phragmites australis (Cav.) Trin. ex Steud., i.e., a common wetland macrophyte, and the associated carbon sequestration capacity has attracted increasing attention. Hanshiqiao Wetland Nature Reserve (HWNR) is a large P. australis wetland in Beijing, China, and provides an ideal case study site for such purpose in an urban setting. In this study, an existing P. australis growth dynamics model was adapted to estimate the plant biomass, which was in turn converted to the associated carbon sequestration capacity in the HWNR throughout a typical year. To account for local differences, the modeling parameters were calibrated against the above-ground biomass (AGB) of P. australis retrieved from hyperspectral images of the study site. We also analyzed the sensitivity of the modeling parameters and the influence of environmental factors, particularly the nutrient availability, on the growth dynamics and carbon sequestration capacity of P. australis. Our results show that the maximum AGB and below-ground biomass (BGB) of P. australis in the HWNR are 2.93 × 103 and 2.49 × 103 g m−2, respectively, which are higher than the reported level from nearby sites with similar latitudes, presumably due to the relatively high nutrient availability and more suitable inundation conditions in the HWNR. The annual carbon sequestration capacity of P. australis in the HWNR was estimated to be 2040.73 gC m−2 yr−1, which was also found to be highly dependent on nutrient availability, with a 50% increase (decrease) in the constant of the nutrient availability KNP, resulting in a 12% increase (23% decrease) in the annual carbon sequestration capacity. This implies that a comprehensive management of urban wetlands that often encounter eutrophication problems to synergize the effects of nutrient control and carbon sequestration is worth considering in future practices.

Sea level rise (SLR) has a significant impact on the ecosystem services in coastal wetlands. Taking the Liaohe Delta as an example, the SLAMM (Sea Level Rise Affecting Marsh Model) was used to simulate the medium-term (2010–2050) and the long-term (2010–2100) of the spatiotemporal changes of land use in the four scenarios (0.5, 1, 1.5, and 2 m) of sea level rise by 2100 and then based on the InVEST (Integrated Valuation of Ecosystem Services and Tradeoffs Model) to assess and compare the impact of SLR on ecosystem services. The results are as follows. (1) The difference in SLR height greatly influences the transformation of the coastal wetland pattern. In 2100, the core construction land would be affected on a large scale for landward salt marsh migration for 1.5 and 2 m SLR scenarios. (2) Due to inundation, erosion, and vegetation succession, the mean total carbon storage for the four scenarios will decrease by about 0.58 × 106 t. The habitat quality is relatively stable, and its value is about 0.7. The nitrogen and phosphorus loads will be reduced by 26.27% and 28.22%, respectively. The region spatial distribution of freshwater marshes will shrink, while the transformation of salt marshes is inconsistent. The large-scale formation of regularly flooded marshes can also provide high levels of ecosystem services as salt marshes. In conclusion, the coastal wetlands show two evolution patterns under the four sea level rise scenarios, the two low ones show a slow change, and the two high ones are large. Quantitative assessment of the effects, scope and intensity of the impact of SLR on the function of ecosystem services in the coastal wetlands can provide reference and indicative significance for wetland development, construction, ecological conservation, and restoration in similar coastal areas under the impact of climate change.

Building inland waterways affects the natural structure, formation, and extent of the riverbed and riparian zone. It alters the hydrology and sediment deposition conditions and hence damages the aquatic ecosystem. To address the effects of the construction of inland waterways on the riverine biome, benthic macroinvertebrate communities were compared at different building stages of inland waterways along a gradient of shipping traffic density at two montane rivers in China. The Shannon–Wiener diversity index of the benthic macroinvertebrate communities ranged from 0.4 to 1.6; the lowest value was recorded in the completed inland waterway, while the highest value was recorded in the unaffected stretch. Principal component analysis and canonical correlation analysis showed the communities in the inland waterways to be distinct from those in the natural riparian habitats. Our results suggest that benthic macroinvertebrate communities can reflect the damage done by the hydromorphological modifications caused by building inland waterways. Benthic macroinvertebrate diversity and abundance should therefore be included when assessing the impact of building and operating inland waterways.

Photocatalysis has attracted wide attention due to its outstanding advantages in dealing with sewage. And compounds of metal oxides and g-C3N4 that possess Z-type heterojunctions have become the star photocatalysts in degrading pollutants. In this paper, a novel one-step method for the preparation of highly efficient photocatalyst of Fe2O3/g-C3N4, using Fe (NO3)3 and urea as raw materials, is described. Under the optimized condition, the one-step synthesized photocatalyst of FeGCN-0.10 showed higher photocatalytic performance compared with the multi-step prepared photocatalyst, and the rate of removing basic fuchsin was 92% (210 min), which was 19.5% higher than that of the latter. Furthermore, different methods were also applied for characterizing Fe2O3/g-C3N4. Structural characterization results confirmed the composites of Fe2O3/g-C3N4. Morphological characterization results showed that spindle-like Fe2O3 particles were distributed more evenly on the layered g-C3N4 compared with the impregnation method. Optical characterization results demonstrated the high intensity of the separated photo-generated electron-hole pairs and of Fe2O3/g-C3N4, which uncovered the removing mechanism of basic fuchsin.

Introduction:Understanding the trophic interactions between plants and herbivorous insects is essential for managing the ecosystem health and sustainability in the context of climate change and anthropogenic disturbance. The Tamarix chinensis is a foundation plant species of salt marshes in northern China, which provides a variety of ecological functions and services in coastal ecosystems such as withstanding storm tide, conserving biodiversity, and preventing shoreline erosion. Outcomes: However, through long-term field observations, for the first time, we found that the health of this population has been suffering from the potential outbreak of a novel wood-borer insect (Zeuzera leuconotum Butler) under multiple stresses, contributing substantially to the degradation of the coastal salt marshes. Discussion and Conclusion: Therefore, there is urgent need and great significance to investigate the potential impact of this herbivorous wood-borer insects on health and sustainability of plant community in coastal ecosystems for in-depth understanding its degradation mechanisms.

Abstract The influence of C insertion on Dzyaloshinskii–Moriya interaction (DMI) as well as current-induced domain wall (DW) motion (CIDWM) and tilting in Pt/Co/Ta racetracks is investigated via a magneto-optical Kerr microscope. The similar DMI strength for Pt/Co/Ta and Pt/Co/C/Ta samples reveals that DMI mainly comes from the Pt/Co interface. Fast DW velocity around tens of m/s with current density around several MA/cm2 is observed in Pt/Co/Ta. However, it needs double times larger current density to reach the same magnitude in Pt/Co/C/Ta, indicating DW velocity is related to the spin-orbit torque efficiency and pinning potential barrier. Moreover, in CIDWM, DW velocity is around 103 times larger than that in field-induced DW motion (FIDWM) with current-generated effective field keeping the same magnitude as applied magnetic field, revealing that the current-generated Joule heating has an influence on DW motion. Interestingly, current-induced DW tilting phenomenon is observed, while this phenomenon is absent in FIDWM, demonstrating that the current-generated Oersted field may also play an essential role in DW tilting. These findings could provide some designing prospects to drive DW motion in SOT-based racetrack memories.

Previous studies mostly focus on an individual delta, or deltas at a global scale, to explore dam effects on deltaic hydrological alteration and morphological evolution, while comparative studies on selected similar deltas remain scarce. In this study, we compare the alteration of river discharge and sediment load, as well as the associated deltaic area and shoreline, of two deltas, namely, the Volta River Delta in Ghana and the Yellow River Delta in China, which are subject to similar forcings and mainstem dam influences. The results show that the sediment loads of the Volta River Delta and Yellow River Delta have decreased abruptly and gradually, respectively, to ~10% of the pre-dam level, presumably due to differences in reservoir capacity and upstream dam location. Sediment decline has led to a decrease of the fluvial dominance ratio, which has also been affected by the river mouth location and shoreline orientation. As a consequence, the area of the Volta River Delta has shifted to a new quasi-equilibrium, whereas the Yellow River Delta has kept prograding. This comparative study provides references for understanding the future evolution of similar deltas around the world.

Electrical spin-orbit torque (SOT) in magnetic insulators (MI) has been intensively studied due to its advantages in spin-orbitronic devices with ultralow energy consumption. However, the magnon torque in the MIs, which has the potential to further lower the energy consumption, still remains elusive. In this work, we demonstrate the efficient magnon torque transferred into an MI through an antiferromagnetic insulator. By fabricating a Pt/NiO/Tm3Fe5O12 heterostructure with different NiO thicknesses, we have systematically investigated the evolution of the transferred magnon torque. We show that the magnon torque efficiency transferred through the NiO into the MI can retain a high value (∼50%), which is comparable to the previous report for the magnon torque transferred into the metallic magnet. Our study manifests the feasibility of realizing the pure magnon-based spin-orbitronic devices with ultralow energy consumption and high efficiency.

Various surface water bodies, such as rivers, lakes and reservoirs, provide water and essential services to human society. However, the long-term spatiotemporal dynamics of different types of surface water bodies and their possible driving factors over large areas remain very limited. Here, we used unprecedented surface water data layers derived from all available Landsat images and further developed two databases on China’s lakes and reservoirs larger than 1 km2 to document and understand the characteristics of changes in different water body types during 2000 to 2019 in China. Our results show that China is dominated by permanent water bodies. The areas of permanent and seasonal water bodies in China increased by 16,631.02 km2 (16.72%) and 16,994.95 km2 (25.14%), respectively, between 2000 and 2019, with permanent and seasonal water bodies exhibiting divergent spatial variations. Lakes and artificial reservoirs larger than 1 km2, which collectively represent a significant proportion of the permanent water bodies in China, displayed net increases of 6884.52 km2 (10.71%) and 4075.13 km2 (36.10%), respectively, from 2000 to 2019; these increases accounted for 41.40% and 24.50%, respectively, of the total permanent water body increment. The expanding lakes were mainly distributed on the Tibetan Plateau, whereas the rapidly growing reservoirs were mainly located on the Northeast Plain and Eastern Plain. Statistical analyses indicated that artificial reservoirs were an important factor controlling both permanent and seasonal water body changes in most of provinces. Climate factors, such as precipitation and temperature, were the main influencing factors affecting the changes in different water bodies in the sparsely populated Tibetan Plateau.

Abstract The extent by which human activities create an inroad for the invasion of exotic plant species and the mechanisms that drive a disturbed ecosystem's resistance to exotic invasion is largely unknown. We investigated the mechanisms by which salt marsh resists cordgrass (Spartina alterniflora) invasion by two key factors: anthropogenic disturbance by ditching and herbivory by the native crab Helice tientsinensis. In northern China, although abiotic resistance (i.e., hyper‐stresses) inhibited the landward invasion of cordgrass to high marshes, our transplant experiments showed that anthropogenic ditching created windows of opportunity for cordgrass invasion to high marshes by enhancing propagule pressure and providing favorable (i.e., low‐salinity and high‐inundation) microhabitats for colonization. Furthermore, a native herbivore exclusion experiment showed that crab grazing strongly suppressed seedling establishment and growth of cordgrass in ditched high marshes, which gradually created native biotic resistance to cordgrass invasion. We conclude that grazing by native herbivores can enhance the resistance of high marshes to cordgrass invasion triggered by anthropogenic ditching disturbance in northern China. These findings highlight that it is critical to investigate ecosystem resistance associated with anthropogenic disturbance to better understand the multiple mechanisms of exotic plant invasion, and we call for integration of these findings into invasion control strategies.

The eastern coast of China provides a network of Important Bird Areas (IBAs) as feeding and breeding habitats, as well as migratory corridors for a large variety of waterbirds. However, long-term coastal reclamation has greatly encroached on coastal wetlands and undermined their functions as waterbird habitats. To identify the impacts of coastal reclamation on waterbird habitats in 2014, we analyzed coastal wetland modifications that have been caused by various reclamation types in 38 IBAs along China's coastline by using remotely sensed data. The distribution data of major waterbird families in 15 IBAs were collected to explore their population responses to habitat modification. The densities of their population were calculated to compare the habitat preferences to the natural and modified habitats. In addition, the index of Reclamation Intensity was used to evaluate the comprehensive impacts of coastal reclamation on waterbirds. The results show that more than half of the wetland areas in the 38 IBAs have undergone modification from various types of land use. The different habitat preferences indicate that the original habitat suitability for waterbirds has been perturbed considerably by the coastal reclamation. Our findings revealed that there are still notable conservation gaps for waterbirds along China's coastline and the opportunity exists for trading off waterbird conservation versus socioeconomic benefits by wise use of artificial wetlands as alternative and provisional habitats for waterbirds. Keywords: Habitat modification, Coastal reclamation, Waterbird distribution, Habitat preference, Important bird area

Rapid invasion of Spartina alterniflora in coastal wetlands throughout the world has attracted much attention. Some field and imagery evidence has shown that the landward invasion of S. alterniflora follows the tidal channel networks as the main pathway. However, the specific patterns and processes of its invasion in salt marshes in relation to tidal channel networks are still unclear. Based on yearly satellite images from 2010 to 2018, we studied the patterning relationship between tidal channel networks and the invasion of S. alterniflora at the south bank of the Yellow River Estuary (SBYRE). At the landscape (watershed and cross-watershed) scale, we analyzed the correlation between proxies of tidal channel network drainage efficiency (unchanneled flow lengths (UFL), overmarsh path length (OPL), and tidal channels density (TCD)) and spatial distribution of S. alterniflora. At the local (channel) scale, we examined the area and number of patches of S. alterniflora in different distance buffer zones outward from the tidal channels. Our results showed that, overall, the invasion of S. alterniflora had a strong association with tidal channel networks. Watershed with higher drainage efficiency (smaller OPL) attained larger S. alterniflora area, and higher-order (third-order and above) channels tended to be the main pathway of S. alterniflora invasion. At the local scale, the total area of S. alterniflora in each distance buffer zones increased with distance within 15 m from the tidal channels, whereas the number of patches decreased with distance as expansion stabilized. Overall, the S. alterniflora area within 30 m from the tidal channels remained approximately 14% of its entire distribution throughout the invasion. The results implicated that early control of S. alterniflora invasion should pay close attention to higher-order tidal channels as the main pathway

Biological invasions have become the focus of considerable concern and ecological research, yet the relative importance of abiotic and biotic factors in controlling the invasibility of habitats to exotic species is not well understood. Spartina species are highly invasive plants in coastal wetlands; however, studies on the factors that control the success or failure of Spartina invasions across multiple habitat types are rare and inconclusive.We examined the roles of physical stress and plant interactions in mediating the establishment of the smooth cordgrass, Spartina alterniflora, in a variety of coastal habitats in northern China. Field transplant experiments showed that cordgrass can invade mudflats and low estuarine marshes with low salinity and frequent flooding, but cannot survive in salt marshes and high estuarine marshes with hypersaline soils and infrequent flooding. The dominant native plant Suaeda salsa had neither competitive nor facilitative effects on cordgrass. A common garden experiment revealed that cordgrass performed significantly better when flooded every other day than when flooded weekly. These results suggest that physical stress rather than plant interactions limits cordgrass invasions in northern China.We conclude that Spartina invasions are likely to be constrained to tidal flats and low estuarine marshes in the Yellow River Delta. Due to harsh physical conditions, salt marshes and high estuarine marshes are unlikely to be invaded. These findings have implications for understanding Spartina invasions in northern China and on other coasts with similar biotic and abiotic environments.

Macrophyte decomposition is important for carbon and nutrient cycling in lake ecosystems. Currently, little is known about how this process responds to detritus quality and water nutrient conditions in eutrophic shallow lakes in which incomplete decomposition of detritus accelerates the lake terrestrialization process. In this study, we investigated the effects of detritus quality and water nutrient concentrations on macrophyte decomposition in Lake Baiyangdian, China, by analyzing the decomposition of three major aquatic plants at three sites with different pollution intensities (low, medium, and high pollution sites). Detritus quality refers to detritus nutrient contents as well as C:N, C:P, and N:P mass ratios in this study. Effects of detritus mixtures were tested by combining pairs of representative macrophytes at ratios of 75:25, 50:50 and 25:75 (mass basis). The results indicate that the influence of species types on decomposition was stronger than that of site conditions. Correlation analysis showed that mass losses at the end of the experimental period were significantly controlled by initial detritus chemistry, especially by the initial phosphorus (P) content, carbon to nitrogen (C:N), and carbon to phosphorus (C:P) mass ratios in the detritus. The decomposition processes were also influenced by water chemistry. The NO(3)-N and NH(4)-N concentrations in the lake water retarded detritus mass loss at the low and high pollution sites, respectively. Net P mineralization in detritus was observed at all sites and detritus P release at the high pollution site was slower than at the other two sites. Nonadditive effects of mixtures tended to be species specific due to the different nutrient contents in each species. Results suggest that the nonadditive effects varied significantly among different sites, indicating that interactions between the detritus quality in species mixtures and site water chemistry may be another driver controlling decomposition in eutrophic shallow lakes.

Managing and identifying the sources of anthropogenic stress in coastal wetlands requires an in-depth understanding of relationships between species diversity and human activities. Empirical and experimental studies provide clear evidence that coastal reclamation can have profound impacts on marine organisms, but the focus of such studies is generally on comparative or laboratory research. We developed a compound intensity index (reclamation intensity index, RI) on hybrid coastal reclamation, to quantify the impacts of reclamation on coastal ecosystems. We also made use of mean annual absolute changes to a number of biotic variables (biodiversity, species richness, biomass of total macrozoobenthos, and species richness and biomass of Polychaeta, Mollusca, Crustacea, and Echinodermata) to determine Hedges’ d index, which is a measure of the potential effects of coastal reclamation. Our results showed that there was significant difference of coastal reclamation intensity between Yellow Sea, East China Sea and South China Sea, the biological changes in effect sizes of the three regions differed greatly over time. Our modelling analyses showed that hybrid coastal reclamation generally had significant negative impacts on species diversity and biomass of macrozoobenthos. These relationships varied among different taxonomic groups and included both linear and nonlinear relationships. The results indicated that a high-intensity of coastal reclamation contributed to a pronounced decline in species diversity and biomass, while lower-intensity reclamation, or reclamation within certain thresholds, resulted in a small increase in species diversity and biomass. These results have important implications for biodiversity conservation and the ecological restoration of coastal wetlands in face of the intensive reclamation activities.