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The anticancer potential of quassinoids has attracted a great deal of attention for decades, and scientific data revealing their possible applications in cancer management are continuously increasing in the literature. Aside from the potent cytotoxic and antitumor properties of these degraded triterpenes, several quassinoids have exhibited synergistic effects with anticancer drugs. This article provides an overview of the potential anticancer properties of quassinoids, including their cytotoxic and antitumor activities, mechanisms of action, safety evaluation, and potential benefits in combination with anticancer drugs.

We report a general flash arc synthesis (FAS) method to batch fabricate alloy micro/nanocrystals of up to eight components on a wafer-scale. Combined with experiments and first-principle calculations, we show that the shape and size distribution of prepared micro/nanocrystals is determined by both the adhesion energy and diffusion coefficient of metal atoms on the highly oriented pyrolytic graphite (HOPG) substrate. Moreover, we show that surface atomic steps in the HOPG substrate can induce self-assembly and anchoring of metal micro/nanocrystals. The proposed method can essentially prepare alloy micro/nanocrystals with any number of components due to the high cooling rate of micro/nanocrystals, which could lead to the quick development of new materials by directly alloying on the nanoscale and facilitate the applications of alloy micro/nanocrystals.

Abstract As a knowledge representation method, knowledge graph is widely used in intelligent question answering systems and recommendation systems. At present, the research on knowledge graph mainly focuses on information query and retrieval based on knowledge graph. In some domain knowledge graphs, specific subgraph structures (patterns) have specific physical meanings. Aiming at this problem, this paper proposes a method and framework of knowledge graph pattern mining based on gat. Firstly, the patterns with specific physical meaning were transformed into subgraph structures containing topological structures and entity attributes. Secondly, the subgraph structure of the pattern is regarded as the query graph, and the knowledge graph is regarded as the data graph, so that the problem is transformed into an approximate subgraph matching problem. Then, the improved relational graph attention network is used to fuse the adaptive edge deletion mechanism to realize the approximate subgraph matching of subgraph structure and attribute, so as to obtain the best matching subgraph. The proposed method is trained in an end-to-end manner. The approximate subgraph matching is realized on the existing data set, and the research work of key pattern mining of complex geological structure knowledge graph is carried out.

Scaly-sided Merganser is an endangered species confined to eastern Asia, primarily breeding in southeast Russia and northeast China. Its breeding range is quite large, with limited information on population dynamics. The Kievka River catchment in far east Russia is one of the most densely populated breeding grounds, providing the only extensive, long-term monitoring on breeding Scaly-sided Merganser. This study assessed the current status of Scaly-sided Merganser and investigated the environmental factors influencing the population. From 2014–2021, the population size at each river reach fluctuated with no directional trends, while the density of Scaly-sided Merganser increased. The result suggested a higher concentration of breeding Scaly-sided Merganser in Kievka River catchment in recent years, particularly preferring downstream area. The species also demonstrated an affinity to less riparian vegetation and higher flow rates. Notably, river flow rate emerges as a potential key issue for designing environmental flows of the breeding habitat for Scaly-sided Merganser, presenting a challenge for researchers and managers.

Abstract The uncertainty of structural interpretation complicates the practical production and application of data-driven complex geological structure modeling technology. Intelligent structural modeling excavates and extracts structural knowledge from structural interpretation through human–machine collaboration and combines structural interpretation to form a new model of complex structural modeling guided by knowledge. Specifically, we focus on utilizing knowledge rule reasoning technology to extract topological semantic knowledge from interpretive data and employ knowledge inference to derive structural constraint information from complex geological structure models, thus effectively constraining the 3D geological structure modeling process. To achieve this, we develop a rule-based knowledge inference system that derives theoretical models consistent with expert cognition from interpretive data and prior knowledge. Additionally, we represent the extracted knowledge as a topological semantic knowledge graph, which facilitates computer recognition and allows estimation of intersection lines during 3D geological modeling, resulting in the creation of accurate models. The applicability of our proposed method to various complex geological structures is validated through application tests using real-world data. Furthermore, our method effectively supports the realization of intelligent structure modeling in real working area.

Ecological restoration projects aim to recover ecosystems that have been degraded, damaged, or destroyed. The effective assessment of these projects is crucial for ensuring that restoration goals are met and for guiding future efforts. The Poplar Ecological Restoration Project (PERP), focused on removing floodplain poplar plantations, is a key environmental initiative in China to preserve the ecological functions and services of the Dongting Lake freshwater wetland complex. Understanding the dynamic changes in ecosystem services and their trade-offs/synergies before and after the project is crucial for ensuring that ecosystem services are maintained and enhanced. This study selected three key ecosystem services, water conservation, carbon storage, and habitat quality, as indicators to assess the PERP. Using the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model and geostatistical methods, including the Spearman correlation analysis and spatial autocorrelation analysis, we explored the ecological outcomes of the project. The results indicated that since its implementation in 2014, the PERP has significantly altered the land use and land cover (LULC) in the lake. Most of the former plantations have been converted into reedbeds (17,404 ha), followed by sedgelands (3841 ha), mudflats (443 ha), shallow waters (382 ha), and deep waters (301 ha). During this period, water conservation and habitat quality initially decreased and then increased, while carbon storage continuously declined. Overall, all assessed services showed an increasing trend except for carbon storage, resulting in a slight decrease in the integrated ecosystem services. Moreover, there were strong bivariate associations among the three investigated ecosystem services, and the synergies were strengthened during the project. Importantly, these synergies became positive after the PERP, meaning that the improvement of one service enhanced others, potentially leading to a more sustainable and resilient ecosystem.

Walkaway vertical seismic profiling (WVSP) is known for its high level of credibility in obtaining the relationship between first-arrival traveltime and detector depth through first-arrival picking. This relationship can be utilized for seismic velocity model inversion to improve velocity model accuracy and rationality. Here, we present a WVSP first-arrival velocity model with velocity structure constraints, by utilizing layer and fault data interpreted by ground seismic structure technique. We constructed a geological structure and layer sequence models based on sedimentary patterns to obtain complex velocity structures. Furthermore, we introduced a smooth regularization term based on the velocity structure into the inversion model to enhance its consistency with geological laws and compensate for the reduced inversion accuracy owing to the regularization term based on flat structures. This approach addressed the limitations of the regularization term based on flat structures, resulting in more accurate and reliable inversion results. Through simulation analysis, the proposed method realized the WVSP first-arrival velocity inversion, with results being closer to those of the real velocity model.

Vertical seismic profiling has garnered widespread attention in the industry as a supplement to seismic exploration due to its higher data quality compared to surface seismic data. However, its unique observation system in which geophones are only distributed within observation wells results in uneven coverage of subsurface structures. This can lead to significant noise when directly applying conventional reverse-time migration techniques used in surface seismic imaging. This study addresses the issue of noise suppression in reverse-time migration imaging associated with walk-away vertical seismic profiling and presents two main innovations. First, a common-receiver reverse-time migration imaging method is proposed, which uses the observation signals as excitation signals for the corresponding shots after reverse-time processing. Second, an excitation-time-constrained cross-correlation imaging condition is introduced to eliminate non-contributing portions of the wavefield, thereby modifying the traditional cross-correlation imaging condition to include an excitation time constraint. The combination of these methods enhances imaging quality by effectively suppressing noise, as demonstrated through theoretical analysis and numerical simulations with synthetic models.

Abstract To provide a basis for further optimization of the polio sequential immunization schedule, this study evaluated the effectiveness of booster immunization with one dose of bivalent oral poliovirus vaccine (bOPV) at 48 months of age after different primary polio immunization schedules. At 48 months of age, one dose of bOPV was administered, and their poliovirus types 1–3 (PV1, PV2, and PV3, respectively)-specific neutralizing antibody levels were determined. Participants found to be negative for any type of PV-specific neutralizing antibody at 24, 36, or 48 months of age were re-vaccinated with inactivated polio vaccine (IPV). The 439 subjects who received a bOPV booster immunization at the age of 48 months had lower PV2-specific antibody levels compared with those who received IPV. One dose of IPV during basic polio immunization induced the lowest PV2-specific antibody levels. On the basis of our findings, to ensure that no less than 70% of the vaccinated have protection efficiency, we recommend the following: if basic immunization was conducted with 1IPV + 2bOPV (especially Sabin strain-based IPV), a booster immunization with IPV is recommended at 36 months of age, whereas if basic immunization was conducted with 2IPV + 1bOPV, a booster immunization with IPV is recommended at 48 months of age. A sequential immunization schedule of 2IPV + 1bOPV + 1IPV can not only maintain high levels of antibody against PV1 and PV3 but also increases immunity to PV2 and induces early intestinal mucosal immunity, with relatively good safety. Thus, this may be the best sequential immunization schedule for polio in countries or regions at high risk for polio.

Abstract Homeostasis for phosphorus (HP) in submerged macrophytes may influence the susceptibility of lakes to regime shifts; however, the mechanisms linking submerged macrophyte HP to regime shifts remain unclear. We conducted an in situ mesocosm experiment to compare the dynamic responses of a high-HP species, Potamogeton maackianus, and a low-HP species, Hydrilla verticillata, to different phosphorus (P) level gradients, as well as their effects on phytoplankton inhibition. The biomass of P. maackianus under mesotrophic P (MP; P concentration 0.05 mg L−1) and eutrophic P (EP; P concentration 0.10 mg L−1) conditions was either non-significantly different from, or lower than that under oligotrophic P conditions (OP; P concentration under detection limit of 0.01 mg L−1). Conversely, H. verticillata biomass under EP was significantly higher than that under MP on day 90, whereas it died under OP. This variable response of submerged macrophyte species to P level gradients increased the relative growth advantage of H. verticillata compared to P. maackianus during eutrophication. The inhibition ratio of phytoplankton (IRP) for P. maackianus was ~15 times higher than that for H. verticillata under EP. Our study demonstrated a trend that submerged macrophyte assemblage IRP increased along with its assemblage HP. Thus, the changes in submerged macrophyte assemblages from high-HP species-dominance to low-HP species-dominance would erode its phytoplankton inhibition capacity, and further promote the regime shift from a clear-water state to a turbid state. Our results advance the regime shift theory from an ecological stoichiometry perspective and highlight the importance of high-HP submerged macrophyte species in the restoration of eutrophic lakes.

Seismic velocity inversion is one of the most critical issues in the field of seismic exploration and has long been the focus of numerous experts and scholars. In recent years, the advancement of machine learning technologies has infused new vitality into the research of seismic velocity inversion and yielded a wealth of research outcomes. Typically, seismic velocity inversion based on machine learning lacks control over physical processes and interpretability. Starting from wave theory and the physical processes of seismic data acquisition, this paper proposes a method for seismic velocity model inversion based on Physical Embedding Recurrent Neural Networks. Firstly, the wave equation is a mathematical representation of the physical process of acoustic waves propagating through a medium, and the finite difference method is an effective approach to solving the wave equation. With this in mind, we introduce the architecture of recurrent neural networks to describe the finite difference solution of the wave equation, realizing the embedding of physical processes into machine learning. Secondly, in seismic data acquisition, the propagation of acoustic waves from multiple sources through the medium represents a high-dimensional causal time series (wavefield snapshots), where the influential variable is the velocity model, and the received signals are the observations of the wavefield. This forms a forward modeling process as the forward simulation of the wavefield equation, and the use of error back-propagation between observations and calculations as the velocity inversion process. Through time-lapse inversion and by incorporating the causal information of wavefield propagation, the non-uniqueness issue in velocity inversion is mitigated. Through mathematical derivations and theoretical model analyses, the effectiveness and rationality of the method are demonstrated. In conjunction with simulation results for complex models, the method proposed in this paper can achieve velocity inversion in complex geological structures.

Throughout evolutionary history, animals are finely tuned to adjust their behaviors corresponding to environmental variations. Behavioral flexibility represents an important component of a species' adaptive capacity in the face of rapid anthropogenetic environmental change, and knowledge of animal behaviors is increasingly recognized in conservation biology. In aquatic ecosystem, variation of water depth is a key factor affecting the availability of food; thus, the foraging behaviors of many waterbirds, especially piscivores. In this study, we compared the foraging behaviors of the Scaly-sided Merganser (Mergus squamatus), an endangered migratory diving duck endemic to East Asia, in habitats with different water depths (Shallow waters: 0–40 ​cm; Deep waters: 40–300 ​cm), using video camera records obtained from the known wintering sites during three winters from 2018 to 2020. Further, the energy expenditure of foraging behavior profile and energy intake based on fish sizes were calculated to study the foraging energetics. In total, 200 effective video footages that contained 1086 ​min with 17,995 behaviors and 163 events of catching fish were recorded. Results showed that: 1) time length for fishing (including eye-submerging, head-dipping, diving and food handling) of M. squamatus in shallow waters was significantly more than in deep waters; 2) M. squamatuss spent significantly more time for preparing (including vigilance, preening and swimming) in deep waters than in shallow waters; 3) the mean catch rate was 0.28 fish/min in shallow waters, which is significantly higher than the value of 0.13 fish/min in deep waters; 4) despite the distinct foraging behavior profiles and energy intakes, M. squamatus showed similar energetics in shallow and deep waters. We concluded that M. squamatus is a good example of behavioral flexibility that aligns with expectations of optimal foraging theory, in that it behaves in accordance to resource availability in different environments, resulting in high foraging efficiency.

Nordmann's Greenshank (Tringa guttifer) is a globally endangered species that has received little research attention. It is threatened by rapid habitat loss, an incomplete network of protected sites, and lack of long-term data on population dynamics. Citizen science data can be combined with survey data to support population estimation and conservation gap analysis. From 2020 to 2021, Nordmann's Greenshank was surveyed in Tiaozini, Xiaoyangkou, and Dongling on the southern coast of Jiangsu Province, China, and the global population of the species was re-evaluated using the data obtained. We integrated citizen science data from eBird and the China Bird Report from 2000 to 2020 with the survey results to identify important habitats harboring over 1% of its total population, and compared this data with existing protected areas to identify gaps in its global conservation. Our survey found that Tiaozini supported at least 1194 individuals. Consequently, its global population was re-estimated to be 1500-2000. Moreover, 45 important habitats were identified based on citizen data and survey results. Although 44.4% and 50.0% of the priority sites in the world and China, respectively, are located outside protected areas, the Conservation Effectiveness Index (C) is 68.4% and 71.1%, respectively, showing that the current coverage of protected areas for this part of its range is reasonable. This study presents the most complete and recent population data to date. Tiaozini is the most important migration stopover site for Nordmann's Greenshanks. The species is under threat in terms of breeding, wintering, and stopover sites. Therefore, we suggest improving monitoring, establishing new protected sites to complete the habitat protection network, and improving the effectiveness of existing habitat protection strategies, including further developing high tide roosting sites.

Abstract The Lesser White‐fronted Goose (Anser erythropus), smallest of the “gray” geese, is listed as Vulnerable on the IUCN Red List and protected in all range states. There are three populations, with the least studied being the Eastern population, shared between Russia and China. The extreme remoteness of breeding enclaves makes them largely inaccessible to researchers. As a substitute for visitation, remotely tracking birds from wintering grounds allows exploration of their summer range. Over a period of three years, and using highly accurate GPS tracking devices, eleven individuals of A. erythropus were tracked from the key wintering site of China, to summering, and staging sites in northeastern Russia. Data obtained from that tracking, bolstered by ground survey and literature records, were used to model the summer distribution of A. erythropus. Although earlier literature describes a patchy summer range, the model suggests a contiguous summer habitat range is possible, although observations to date cannot confirm A. erythropus is present throughout the modeled range. The most suitable habitats are located along the coasts of the Laptev Sea, primarily the Lena Delta, in the Yana‐Kolyma Lowland, and smaller lowlands of Chukotka with narrow riparian extensions upstream along major rivers such as the Lena, Indigirka, and Kolyma. The probability of A. erythropus presence is related to areas with altitude less than 500 m with abundant wetlands, especially riparian habitat, and a climate with precipitation of the warmest quarter around 55 mm and mean temperature around 14°C during June‐August. Human disturbance also affects site suitability, with a gradual decrease in species presence starting around 160 km from human settlements. Remote tracking of animal species can bridge the knowledge gap required for robust estimation of species distribution patterns in remote areas. Better knowledge of species' distribution is important in understanding the large‐scale ecological consequences of rapid global change and establishing conservation management strategies.

Floodplain wetlands are among the most dynamic ecosystems on Earth, featuring high biodiversity and productivity. They are also sensitive to anthropogenic disturbances and are globally threatened. Understanding how flow regime drives the spatiotemporal dynamics of wetland habitats is fundamental to effective conservation practices. In this study, using Landsat imagery and the random forest (RF) machine learning algorithm, we mapped the winter distribution of four wetland habitats (i.e., Carex meadow, reedbed, mudflat, and shallow water) in East Dongting Lake, a Ramsar wetland in the middle to lower Yangtze Basin of China, for 34 years (1988–2021). The dynamics of wetland habitats were explored through pixel-by-pixel comparisons. Further, the response of wetland habitats to flow regime variations was investigated using generalized additive mixed models (GAMM). Our results demonstrated the constant expansion of reedbeds and shrinkage of mudflats, and that there were three processes contributing to the reduction in mudflat: (1) permanent replacement by reedbed; (2) irreversible loss to water; and (3) transitional swapping with Carex meadow. These changes in the relative extent of wetland habitats may degrade the conservation function of the Ramsar wetland. Moreover, the duration of the dry season and the date of water level withdrawal were identified as the key flow regime parameters shaping the size of wetland habitats. However, different wetland vegetation showed distinct responses to variations in flow regime: while Carex meadow increased with earlier water withdrawal and a longer dry season, reedbed continuously expanded independent of the flow regime corresponding to the increase in winter rainfall. Our findings suggested that flow regime acts in concert with other factors, such as climate change and sand mining in river channels, driving wetland habitat transition in a floodplain landscape. Therefore, effective conservation can only be achieved through diverse restoration strategies addressing all drivers.

Abstract Studying social‐behavior and species associations in ecological communities is challenging because it is difficult to observe the interactions in the field. Animal behavior is especially difficult to observe when selection of habitat and activities are linked to energy costs of long‐distance movement. Migrating communities tend to be resource specific and prefer environments that offer more suitability for coexisting in a shared space and time. Given the recent advances in digital technologies, digital video recording systems are gaining popularity in wildlife research and management. We used digital video recording cameras to study social interactions and species–habitat linkages for wintering waterbirds communities in shared habitats. Examining over 8,640 hr of video footages, we built tetrapartite social‐behavioral association network of wintering waterbirds over habitat (n = 5) selection events in sites with distinct management regimes. We analyzed these networks to identify hub species and species role in activity persistence, and to explore the effects of hydrological regime on these network characteristics. Although the differences in network attributes were not significant at treatment level (p = .297) in terms of network composition and keystone species composition, our results indicated that network attributes were significantly different (p = .000, r2 = .278) at habitat level. There were evidences suggesting that the habitat quality was better at the managed sites, where the formed networks had more species, more network nodes and edges, higher edge density, and stronger intra‐ and inter‐species interactions. In addition, we also calculated the species interaction preference scores (SIPS) and behavioral interaction preference scores (BIPS) of each network. The results showed that species synchronize activities in shared space for temporal niche partitioning in order to avoid or minimize any potential competition for shared space. Our social network analysis (SNA) approach is likely to provide a practical use for ecosystem management and biodiversity conservation.

Pancreatic cancer remains one of the cancers with the poorest prognosis bearing an overall 5-year survival rate of about 5%. Efficient new chemotherapic drugs are still highly desired. Here, bruceine A, a quassinoid identified from the dried fruits of Brucea javanica (L.) Merr., displayed the most potent anti-proliferation activity against pancreatic cancer in vitro and in vivo. Phosphoproteomic analysis revealed p38α MAPK phosphorylation was involved in bruceine A’s action in MIA PaCa-2 cells. Utilizing fortebio octet system and microscale thermophoresis, we found p38α MAPK had high affinity for bruceine A. Molecular docking and molecular dynamic simulations showed that bruceine A widely bound to residues (Leu171, Ala172, Met179, Thr180, Val183) in P-loop of p38α MAPK. Key determinants of bruceine A binding with P-loop of p38α MAPK were 19-CO, 22-CH3, 32-CH3, and 34-CH3. Taken together, our findings demonstrate that bruceine A binds directly to p38α MAPK, which can be used to probe the role of p38α MAPK phosphorylation in pancreatic cancer progression, and as a novel lead compound for pancreatic cancer therapy.

By combining satellite tracking, land-cover extracted from Landsite 8 images, and the traditional stable isotope analysis, we studied the habitat selection and food preference of a vulnerable migratory waterbird, the White-naped Crane (Grus vipio), in one of its key stagging sites, the Shandian River Basin in the semi-arid northern China, to provide knowledge that is critical for its conservation in the Anthropocene. Our results showed that the White-naped Cranes used both uplands and natural wetlands in the stopover site. While the cranes used farmland and natural land cover equally as night-time roosting grounds, they spent most daytime foraging at farmlands. Despite the extensive usage of croplands as their foraging ground, the Bayesian mixing models based on stable isotopic analysis revealed that crop residues after harvesting, such as Maize (Zea mays) and Naked Oat (Avena chinensis), were only a small fraction of the White-naped Cranes’ diet (∼19%), and their diet composited mainly natural plants, such as Allium ledebourianum, Potentilla anserina, and P. tanacetifoli. Moreover, more than 20% of the total wetlands in the region were modelled as home range of the cranes. On contrast, less than 10% of croplands and about 1% of the unused uplands were identified as home range. In addition, the entire core habitats were located in natural wetlands. Our findings demonstrated the importance of natural wetlands for the survival of the threatened crane. However, the satellite-derived land cover data showed that croplands increased rapidly in the last decade in this area, at the expense of natural wetlands. With the sharp decrease of White-naped Crane population in China, the conservation of stopover sites becomes imperative. Based on our analysis, we recommend the following management actions: conserving adequate natural wetland area, regulating anthropogenic pressures such as the use of herbicides, expanding the duration and extent of current conservation regulations, establishing a comprehensive monitoring program, and initiating basin-scale ecological restoration, for effective conservation of this threatened species. These integrated conservation strategies for migratory waterbirds are necessary, considering the rapid land-cover changes and agricultural expansion that have been occurring in East Asian-Australasian Flyway, especially in the semi-arid temperate zone.

This study investigated the anti-hepatoma molecular mechanism of Alisol G, which is an effective component of the Chinese medicine Alisma orientalis, in the presence of metal ions Cu2+ and Fe3+ based on c-myc DNA. Here, a combination of Alisol G and metal ions (Cu2+, Fe3+) to augment anti-hepatoma efficiencies of Alisol G has been identified by methyl thiazolyl tetrazolium (MTT) assay. Network pharmacology revealed that c-myc DNA was the potential target of Alisol G with respect to its anti-hepatoma effects. By performing multi-spectroscopic analyses, we showed that the interaction of Alisol G with c-myc DNA was a process of static quenching. The binding constants and thermodynamic constants indicated that a 1:1 complex was formed between Alisol G and c-myc DNA. Moreover, metal ions strengthened the interaction between Alisol G and c-myc DNA. Molecular docking and molecular dynamics simulation further unveiled that the higher binding affinity between Alisol G-Fe3+ complex and c-myc DNA as compared to Alisol G-Cu2+ complex. This probably resulted from the polarization of metal ions and the structural flexion of Alisol G. The C22-O31-H76 and C18-O32-H77 of Alisol G were key groups in the interaction with c-myc DNA. Addition of metal ion, had greatly changed the c-myc DNA-binding domain of Alisol G while didn’t affect the kinetic stability of the interaction, thus facilitating the insertion of Alisol G into c-myc DNA A-T base pair. Importantly, the DG113 of c-myc DNA was important for its binding to metal ions. Together, our findings suggested that Alisol G in combination with metal ions may be an efficient and promising option for the treatment of liver cancer.

Climate change has become an important cause of the loss of bird habitat and changes in bird migration and reproduction. The lesser white-fronted goose (Anser erythropus) has a wide range of migratory habits and is listed as vulnerable on the IUCN (International Union for Conservation of Nature) Red List. In this study, the distribution of suitable breeding grounds for the lesser white-fronted goose was assessed in Siberia, Russia, using a combination of satellite tracking and climate change data. The characteristics of the distribution of suitable breeding sites under different climate scenarios in the future were predicted using the Maxent model, and protection gaps were assessed. The analysis showed that under the background of future climate change, temperature and precipitation will be the main climatic factors affecting the distribution of breeding grounds, and the area associated with suitable breeding habitats will present a decreasing trend. Areas listed as an optimal habitat only accounted for 3.22% of the protected distribution; however, 1,029,386.341 km2 of optimal habitat was observed outside the protected area. Obtaining species distribution data is important for developing habitat protection in remote areas. The results presented here can provide a basis for developing species-specific habitat management strategies and indicate that additional attention should be focused on protecting open spaces.

Anthropogenic disturbance to natural hydrological connectivity, both longitudinal, lateral, and vertical, is threatening the ecological integrity of the freshwater realm. River-floodplain system is particularly adversely affected by the reduction in lateral hydrological connectivity (LHC), representing one of major biodiversity hotspots under increasingly pressure. Many studies have demonstrated that LHC has great influence on the spatial variations of flora and fauna communities (i.e. spatial β diversity) through facilitating dispersal. However, to fully understand the impact of anthropogenic disturbances on biodiversity, we must also understand how ecological communities change over time (i.e. temporal β diversity, TBI) and the underlying processes. To evaluate the processes structuring ecological communities, we examined the macroinvertebrate TBI in habitats along the gradient of LHC for an entire hydrological cycle in West Dongting Lake, a Ramsar-listed floodplain wetland at the middle reach of Yangtze River. Our results showed that the total spatial β diversity fluctuated with water level and peaked at high-water phase, and LHC was the driving forcing affecting both species richness and abundance in all hydrological periods. In particular, species richness and abundance were highest in habitats with medium LHC levels for water-rising and high-water periods reflecting the intermediate disturbance hypothesis except for water-recessing, during which there was no clear pattern. While replacement determined β diversity in most sites at water-rising and high-water phases, the contribution of nestedness were high during water-withdrawing phase. From water-rising to high-water, macroinvertebrates from other habitats spread to the modified mudflats, which had the lowest LHC, along with the floods. During water-withdrawing period, β diversity and its turnover component of all habitats were low compared with other hydrological phases. Temporal β diversity analysis illustrated that the species dispersal was the main mechanism underlying the temporal and spatial variations in the observed community patterns. These findings demonstrated that hydrological connectivity was critical to maintaining the ecological integrity of river-floodplain ecosystems.

The middle and lower reaches of the Yangtze River are the most important areas for geese to overwinter in the East Asian–Australasian Flyway, where about 180,000 geese fly to overwinter each year. Over the past 20 years, the region has experienced extensive and rapid land cover changes that may have exceeded the adaptability of geese, and have led to suitable goose habitat area loss, thereby, reducing the stability of the geese population. In order to identify the suitable goose habitat areas in this region, based on ensemble modeling and satellite tracking data, in this study, we simulated the spatial distribution changes in the suitable goose habitat areas over the past 20 years. The results showed that the suitable goose habitat areas had suffered varying degrees of loss, among which, the lesser white-fronted goose had the greatest suitable goose habitat area loss of over 50%. Moreover, we found that wetlands, lakes, and floodplains were the key components of suitable goose habitat areas, and the categories (land use) showed significant differences in different periods (p < 0.01). This may be one of the main reasons for the decrease in suitable goose habitat areas. The results of this study provide an important reference for the adaptive management and protection of geese in the middle and lower reaches of the Yangtze River.

• The decline of submerged macrophytes in shallow lakes and wetlands has cascade effects on regional and global biodiversity. In the last two decades, the rapid disappear of macrophyte beds in the floodplain lakes of the middle lower Yangtze River has become a great concern for the ecological security of the region.• This study aims to quantify the effects of water depth on biomass production and clonal (i.e. stolons and winter buds) and sexual reproduction (i.e. fruits) of Vallisneria natans, a cosmopolitan, perennial submergent species.• Results of the research clearly demonstrated the unimodal relationship between biomass production and water depth, and there was an optimal range of 35–50 cm, beyond which total biomass decreased. Also, both clonal and sexual reproductive outputs decreased with water depth. Furthermore, for the first time, the study revealed the distinct reproduction patterns of the individuals originated from seeds and clonal propagules. While seed-generated plants produced significantly more fruits (and no winter buds), plants developed from clonal propagules produced more stolons and winter buds.• There findings plead further researches on V. natans seedling establishment and reproductive ecology because of the importance of winter buds as food for wintering waterbirds in the middle Yangtze floodplains.

In the last 15 years, the west population of white-naped crane (Antigone vipio) decreased dramatically despite the enhanced conservation actions in both breeding and wintering areas. Recent studies highlighted the importance of protecting the integrity of movement connectivity for migratory birds. Widespread and rapid landcover changes may exceed the adaptive capacity of migrants, leading to the collapse of migratory networks. In this study, using satellite tracking data, we modeled and characterized the migration routes of the white-naped crane at three spatial levels (core area, migratory corridor, and migratory path) based on the utilization distribution for two eras (1990s and 2010s) spanning 20 years. Our analysis demonstrated that the white-naped crane shifted its migratory route, which is supported by other lines of evidences. The widespread loss of wetlands, especially within the stopover sites, might have caused this behavioral adaptation. Moreover, our analysis indicated that the long-term sustainability of the new route is untested and likely to be questionable. Therefore, directing conservation effects to the new route might be insufficient for the long-term wellbeing of this threatened crane and large-scale wetland restorations in Bohai Bay, a critical stopover site in the East Asian-Australasian flyway, are of the utmost importance to the conservation of this species.

Large river floodplain systems (LRFS) are among the most diverse and dynamic ecosystems. Accurately monitoring the dynamics of LRFS over long time series is fundamental and essential for their sustainable development. However, challenges remain because the spatial distribution of LRFS is never static due to inter- and intra-annual changes in environmental conditions. In this study, we developed and tested a methodological framework to re-construct the long-term wetland dynamics in Dongting Lake, China, utilizing an unsupervised machine-learning algorithm (UMLA) on the basis of MODIS (Moderate Resolution Imaging Spectroradiometer) EVI (Enhanced Vegetation Index) time series. Our results showed that the UMLA achieved comparable performance to the time-consuming satellite image segmentation method with a Kappa coefficient of agreement greater than 0.75 and an overall accuracy over 85%. With the re-constructed annual wetland distribution maps, we found that 31.35% of wet meadows, one of most important ecological assets in the region, disappeared at an average rate of c.a. 1660 ha year−1 during the past two decades, which suggests that the Dongting Lake is losing its ecological function of providing wintering ground for migratory water birds, and remediation management actions are urgently required. We concluded that UMLA offers a fast and cost-efficient alternative to monitor ecological responses in a rapidly changing environment.

Maillard reaction products (MRPs) could offer flavor and aroma for food, and also render functional characteristics. In this work, three squid skin Maillard reaction products with glucose (GSS), fructose (FSS) and lactose (LSS) were prepared, whose volatile compounds were analyzed by gas chromatography-mass spectrometer. And the antibacterial activities of three Maillard reaction products against Escherichia coli, methicillin-resistant Staphylococcus aureus and Vibrio harveyi were investigated. The results showed that the volatile compounds of squid skin MRPs mainly contained alcohol, acid, phenol, ester, aldehyde, alkane, alkene, amide and ester, among which alcohol was the predominant component in the GSS and LSS, accounting for 53.87±6.02 % and 83.67±3.64%, respectively, however, acid was predominant component in the FSS, accounting for 54.19±3.38 %. Surprisingly, 2, 6-di-tert-butyl-4-methylphenol (BHT), as a synthetic antioxidant, was firstly identified in these three MRPs, which directly indicated squid skin MRPs have antioxidant activities. It is demonstrated that the antibacterial abilities of LSS and GSS were superior to that of FSS, and Escherichia coli was the most sensitive to the three MRPs among the three tested bacteria. This study demonstrates squid skin MRPs possess antioxidant and antibacterial abilities, which shows promising and far-ranging prospect in the fields of food additives.

This paper demonstrates the impact of an endemic fossorial animal, plateau pika (Ochotona curzoniae), on soil properties and N2O flux at the Zoige Wetland. Pika burrow and control sites without disturbance by pika were selected to measure the soil water content, bulk density, soil organic matter (SOM), NH4-N content and NO3-N content in August 2012. N2O fluxes were measured with static opaque chambers at these sites in June and August 2012. Pika burrowing altered soil aeration by transferring deeper soil to the surface and by constructing underground burrows, which significantly increased bulk density, and reduced soil water content, SOM and NH4-N content at 0-10 cm and 10-20 cm soil depth. N2O flux had a significant correlation with bulk density, SOM and NH4-N content. Pika burrowing significantly influenced N2O flux by increasing N2O flux at the control site from near zero to 0.063±0.011 mg m-2 h-1. Our findings described how pika burrowing influences the soil traits and significantly increases the principal greenhouse gas N2O emission. As plateau pika was commonly considered as a pest, our findings give a novel clue to effectively manage populations of plateau pika on the Qinghai-Tibet Plateau from the perspective of greenhouse gas emission.

Floodplain wetlands are valuable ecosystems for maintaining biodiversity, but are vulnerable to hydrological modification and climatic extremes. The floodplain wetlands in the middle Yangtze region are biodiversity hotspots, particularly important for wintering migratory waterbirds. In recent years, extremely low winter water level events frequently occurred in the middle Yangtze River. The hydrological droughts greatly impacted the development and distribution of the wet meadows, one of the most important ecological components in the floodplains, which is vital for the survival of many migratory waterbirds wintering in the Yangtze region. To effectively manage the wet meadows, it is critical to pinpoint the drivers for their deterioration. In this study, we assessed the effects of hydrological connectivity on the ecological stability of wet meadow in Poyang Lake for the period of 2000 to 2016. We used the time series of MODIS EVI (Enhanced Vegetation Index) as a proxy for productivity to infer the ecological stability of wet meadows in terms of resistance and resilience. Our results showed that (1) the wet meadows developed in freely connected lakes had significantly higher resilience; (2) wet meadows colonizing controlled lakes had higher resistance to water level anomalies; (3) there was no difference in the resistance to rainfall anomaly between the two types of lakes; (4) the wet meadow in freely connected lakes might approach a tipping point and a regime shift might be imminent. Our findings suggest that adaptive management at regional- (i.e., operation of Three Gorges Dam) and site-scale (e.g., regulating sand mining) are needed to safeguard the long-term ecological stability of the system, which in term has strong implications for local, regional and global biodiversity conservation.

Peatlands contain large amount of carbon stock that is vulnerable to release into the atmosphere. Mostly because of human impact, the peatlands at Zoige Wetlands face severe degradation, and the groundwater table is now lower than before, which has increased the population of the plateau zokor, a burrowing rodent. However, the impact of these changes on ecosystem carbon flows has not been studied. To investigate how the plateau zokor and the groundwater level alter the ecosystem respiration of the Zoige peatlands, we sampled the CO2 flux of hummocks shaped by the zokors and compared it with the CO2 flux of undisturbed sites with different groundwater table levels. The soil organic carbon (SOC), soil water content (SWC) and soil temperature at 5 cm (T5) were measured. SOC showed no significant difference among the four sampling sites and did not correlate with the CO2 flux, while SWC was found to partly determine the CO2 flux. A linear equation could adequately describe the relationship between the natural logarithm of the ecosystem respiration and the soil temperature. It is demonstrated that descending groundwater table might accelerate ecosystem respiration and the CO2 flux from hummocks was higher than the CO2 flux from the control site in the non-growing season. With rising temperature, the CO2 flux from the control site accelerated faster than that from the hummocks. Our results show that ecosystem respiration was significantly lower from hummocks than at the control site in the growing season. The results on the impact of zokors on greenhouse gas emissions presented in this paper provide a useful reference to help properly manage not only this, but other litter-burrowing mammals at peatland sites.

Wetlands, and especially their littoral zones, are considered to be CH4 emissions hotspots. The recent creation of reservoirs has caused a rapid increase in the area of the world's littoral zones. To investigate the effects of water depth and water level fluctuation on CH4 fluxes, and how these are coupled with vegetation and nutrients, we used static closed chamber and gas chromatography techniques to measure CH4 fluxes in the littoral zone of a large reservoir near Beijing, China, from November 2011 to October 2012. We found that CH4 flux decreased significantly along a transect from open water to dry land, from 3.1 mg m(-2) h(-1) at the deep water site to approximately 1.3 mg m(-2) h(-1) at the shallow water site, and less than 0.01 mg m(-2) h(-1) in the non-flooded area. Water level influenced CH4 flux by affecting soil properties including soil redox potential, soil carbon and nitrogen, and bulk density. The largest emission of all was from the seasonally flooded site after a flooding event (up to 21.1 mg m(-2) h(-1)), which may have been caused by vegetation decomposition. Submerged sites had greater emissions, while the driest site had lower emissions. Immediately after the monthly measurements had been made, we removed the aboveground vegetation to enable an assessment of the gas transportation per unit of biomass. Removal of biomass decreased emissions by up to 53%. These results indicated the dominant effect of water depth on CH4 flux through effects of soil conditions, plant species composition and distribution. This study suggests that temporally flooded wetlands, including littoral zones, contribute significantly to the global CH4 burden. However, the current challenge is to capture their spatial extent and temporal variation in the fluxes.