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• Established conservation key areas identification methodology. • Conducted conservation Gap analysis combining global data with local characteristics. • Delineated six conservation priority levels for the blank areas of nature reserves. The global system of nature reserves is facing adjustment and restructuring towards the goal of harmonizing ecological conservation with regional development. We use multiple ecoregion data at both global and national scales as ecological indicators to explore the gap areas of China's nature reserves, which can help to build a global network of nature reserve systems and lay a spatial foundation for global biodiversity conservation. This paper comprehensively resorts to the ideas and modeling approaches involved in gap analysis, conservation prioritization analysis and eco-region planning. After identifying in both global and national scales the potential areas with gaps in national nature reserves in China, it proposes conservation priority areas and optimization strategies. The study finds that in a global extent, the areas with the gaps in China cover a large area and are distributed widely, mostly on the both sides of the Tengchong-Heihe Line. The conservation priority areas are concentrated in mid-subtropical humid areas, plateau subtropical sub-humid areas and semi-arid areas, and plateau temperate humid/sub-humid areas. These areas are usually not sufficiently protected due to their diversified landforms, complex ecosystems and lack of protection measures. The results have verified and identified the areas with gaps in the building of Chinese national nature reserve system. They may make a unique and important contribution to global ecological conservation efforts in terms of protected area system optimization and conservation network building. This paper analyses the conservation gaps in China's national nature reserves and proposes conservation priority areas for optimising the layout of the nature reserve network. [ABSTRACT FROM AUTHOR]

• Endangered plants in Sanjiangyuan mainly locate in the east and the south. • Distribution of endangered plants will expand to the west and north in the future. • Habitats in the northeast are at the highest ecosystem risk. • Most of the highest risk areas are not strictly protected. Sanjiangyuan, called the "Water tower of Asia", is critically important in the ecological services of water provision and regulation and in biodiversity conservation. To strengthen protection in this eco-region, The Chinese government established the Sanjiangyuan National Nature Reserve (SNNR) in 2001 and Sanjiangyuan National Park (SNP) in 2014. To assess the effectiveness of these two conservation practices, on the endangered plant species, we used an integrated method to identify the priority areas of the endangered plant species in the Sanjiangyuan Area which showed if some areas need more conservation efforts. After identifying the potential habitats of high-valued species in Sanjiangyuan with MaxENT, a model that combined the hotspots of endangered plant species richness (H), vegetation condition (V), soil condition (S), human disturbance (D) and climate change impact (C) was used to calculate ecosystem risk (ER) associated with each habitat. Projections of climate modeling show that the distribution of endangered plants in Sangjiangyuan will expand to the west and north with the warmer and wetter climate in the future. In both current and future scenarios, the habitats in the northeast of the SNNR are at the highest ecosystem risk and need to be protected strictly. However, most of the high ecosystem risk/conservation priority regions we identified - either current or predicted future status (in 2070 under RCP 2.6) were not protected by SNNR or SNP. Identified conservation gaps call for the well-targeted planning and delineated scientific interventions for protecting the key habitats of these endangered plant species. Conservation priority should be given to eastern Xinghai County and northeastern Tongde County in the east of SNNR, where the habitats are at high ecosystem risk and have high conservation priority. [ABSTRACT FROM AUTHOR]

Brominated flame retardants (BFRs) such as tetrabromobisphenol A (TBBPA) and hexabromocyclododecanes (HBCDs) are of ecological concern due to their ubiquitous presence and adverse effects. There is a paucity of data on environmental fate of such compounds in mangrove wetlands, which are unique ecosystems in coastal intertidal areas and act as natural sinks for many pollutants. In this study, mangrove plants and sediments were collected from an urban nature reserve in South China to investigate bioaccumulation and translocation of TBBPA and HBCDs. The mean (range) concentrations of TBBPA and ΣHBCD in roots, stems and leaves were 67 (

[Display omitted] • The combinatorial optimization to select the suitable scales for multi-scale habitat selection modeling (HSM). • This approach achieved high accuracy in a case study of the red-crowned crane. • The percentage cover of Scirpus mariqueter at 500 m scale is the most important environmental covariate. Multi-scale habitat selection modeling (HSM) has garnered attention due to its ability to incorporate scale dependence of species. The key of multi-scale HSM is to select the appropriate combination of scales for different resources or environmental conditions, and then construct a set of multi-scale environmental covariates as the features of HSM. However, the existing scale selection methods do not determine the combination of scales under a unified model. In this study, a combinatorial optimization approach is proposed. We regard the combination of different scales as a search space, and use a heuristic optimization algorithm to search for the best-fitting model to determine the optimal scales for each resource or environmental condition. In a case study conducted in Yancheng National Nature Reserve, the proposed approach is applied to model the habitat selection of the endangered red-crowned crane. We compare the proposed method with single-scale, random-scale and other multi-scale approaches. The results show that the combination of scales selected based on the proposed method obtained the best accuracy in the spatial prediction of habitat suitability with a test AUC of 0.865 for the daytime scenario and 0.932 for the nighttime scenario. Moreover, the selected scales are utilized to generate response curves, providing suggestions for habitat restoration and management of the red-crowned crane population in the nature reserve. [ABSTRACT FROM AUTHOR]

Carbohydrates, which form a large pool of carbon in plant litter, are a major driver of litter dynamics and benthic food webs in Spartina -invaded mangrove ecosystems. However, there are large gaps in knowledge regarding the effects of exotic leaf litter carbohydrates on benthic carbon assimilation. In this study, the dynamics of carbohydrates, including cellulose, lignin and monosaccharides (glucose, mannose, galactose, xylose and arabinose), during the leaf litter decomposition of the exotic Spartina alterniflora (SA) and the native mangrove plant Kandelia obovata (KO) were analyzed and compared. Meanwhile, the differences in the δ13C values of cellulose and lignin were used to analyze the utilization of leaf litter carbohydrates by polychaetes after Spartina invasion. Our results showed that the decomposition rate of exotic SA leaf litter was lower than that of KO leaf litter. The contents of cellulose, glucose and galactose in SA leaf litter were higher than those in KO leaf litter (P < 0.05). The decomposition rates of cellulose and monosaccharides (arabinose, xylose, mannose and galactose) in KO leaf litter were faster than those in SA leaf litter (P < 0.05). However, there was no significant difference in the decomposition rates of lignin in the leaf litter between exotic SA leaf litter and native KO leaf litter (P > 0.05). In the native KO plot, the carbohydrates of KO leaf litter contributed to >55% (cellulose, 26.91–28.02%; lignin, 28.05–28.64%) of the organic carbon sources of polychaetes. However, in the exotic SA plot, the carbohydrates of exotic SA leaf litter contributed to >65% (cellulose, 36.83–38.30%; lignin, 28.47–30.52%) of the organic carbon sources of polychaetes. The obtained results suggested that Spartina invasion increased the assimilation of cellulose by polychaetes. The high content and low decomposition rate of cellulose in the carbohydrates of exotic SA leaf litter might be important mechanisms for the carbon assimilation changes in the benthos of Spartina- invaded mangrove ecosystems. Given that Spartina has colonized in the Zhangjiang Estuary Mangrove Reserve, this study provides a theoretical basis for the recovery of benthos after ecological restoration. Furthermore, the mechanisms of carbohydrate assimilation by different benthos of different ecosystems should be comprehensively considered in the future. [Display omitted] • Spartina invasion reduced the litter decomposition rate in mangrove wetlands. • Cellulose and monosaccharides in native mangroves decomposed faster than those in exotic Spartina. • Benthic polychaetes assimilated more cellulose from exotic litter after Spartina invasion. • The high content and low decomposition rate of cellulose are major drivers of nutrient cycles and benthic food webs in Spartina -invaded mangroves. [ABSTRACT FROM AUTHOR]

• Annual average NDVI demonstrate significant increasing trend in the three subregions. • NDVI values more than 0.8 mainly concentration on the 1049–2349 m, 947–2547 m, 617–2817 m in the three subregions. • The combination of extreme climate indices can better explain the NDVI change on the month and year scale in the three subregions. Southwest China (SWC) is a critical hotspot of biodiversity and highly sensitive to climate change. To better protect biodiversity, many National Nature Reserves have been established to maintain viable populations of species and minimize their habitat loss. However, the response of the normalized difference vegetation index (NDVI) in National Nature Reserves to extreme climate events has not been described. We analyzed NDVI changes and made several key observations: (1) from 1998 to 2019, annual average NDVI trends of 0.00421 yr−1, 0.00514 yr−1, and 0.00529 yr−1 were significantly increasing and NDVI values more than 0.8 were mainly concentrated at 1049–2349 m, 947–2547 m, 617–2817 m, in the National Nature Reserves of Hengduan Mountain (NNRHDM), Sichuan basin (NNRSCB), and Yunnan-Guizhou Plateau (NNRYGP), respectively. The change trends in different altitude bins were more significant in the NNRYGP; (2) extreme cold (warm) indices significantly decreased (increased) in the NNRHDM, NNRSCB and NNRYGP, extreme precipitation indices increased in the NNRHDM, and decreased in the NNRSCB and NNRYGP; (3) the combination of extreme temperature indices can better explain NDVI change in the NNRSCB and NNRYGP, and the combination of extreme temperature and precipitation indices can better explain the NDVI change in the NNRHDM on the monthly scale. Overall, the NDVI green trend is more obvious in the NNRYGP than in the NNRHDM and NNRSCB, and is more sensitive to extreme climate change, especially extreme temperature. Our findings showed that although the National Nature Reserves have achieved remarkable results in conservation, future work should focus on the development of adaptation and alleviation strategies to prevent extreme climate events (especially extreme temperature events) that could promote vegetation degradation in these sensitive areas. [ABSTRACT FROM AUTHOR]

• The spatiotemporal dynamics of land use and ESV in China National Nature Reserve—Shennongjia Forest Region are assessed from the perspective of "past-present-future" • Vulnerability analysis of ecosystem services was carried out. • ESV and vulnerability under the ecological protection scenario are improved, compared with the natural development scenario. • The ecological protection policy of Shennongjia Forest Region was proposed. Accurate assessment of the ecosystem service value (ESV) of China National Nature Reserves is of great significance to the protection of regional ecological environment. In this paper, taking Shennongjia Forest Region as an example, based on the land use data of three phases in 2000, 2010 and 2020, we quantitatively evaluate the spatiotemporal evolution characteristics of the regional ESV, and use the FLUS model to simulate the land use layouts and the spatial distribution characteristics of the ESV under the two scenarios in 2035, and carry out the vulnerability analysis of the regional ecosystem services.. The conclusions are as follows: (1) From 2000 to 2020, the overall ESV in Shennongjia Forest Region decreased by 15.48 million yuan, and support services and regulation services always played a decisive role in the overall ESV. (2) The area of cultivated land and grassland continued to shrink from 2000 to 2020, resulting in the reduction of ESV by 2.6 million yuan and 3.67 million yuan respectively. The contribution of woodland to the ESV was the largest, accounting for more than 95% in the three periods. (3) Under the natural development scenario, cultivated land, woodland and grassland continue to decline. Under the ecological protection scenario, the area of cultivated land decreases even more, but the area of woodland and grassland increases, and the layouts of construction land are more compact. The potential impact (PI) indexes of the region in 2000–2010 and 2010–2020 were negative, while that in 2020-2035Q1 is −2.01, which further worsens the vulnerability of ecosystem services. However, the PI index in 2020-2035Q2 turns positive, which is 2.29, indicating that the goal of the regional government to protect the ecological space under this scenario is basically realized. The research results can provide some reference for Shennongjia Forest Region and other National Nature Reserves to give consideration to both ecological environment protection and high-quality development. [ABSTRACT FROM AUTHOR]

• An ABM for socio-ecological simulation in small-scale coupled human-nature systems. • A microeconomic basis for heterogeneous agents with partial rationality. • A rich set of mechanisms of two-way human-nature interactions. • Low data demand, and broad implementability in developing countries. • A case study in Wolong, China showing the validity of the model. The tension between economic development and ecological conservation has always been a hotly debated topic, especially in critical ecologically sensitive areas such as nature reserves in the developing world. Complexity modeling methods, such as Agent-based Models (ABM), are a feasible way to study such Coupled Human and Nature Systems (CHANS). This paper presents an ABM named Socio-Econ-Ecosystem Multipurpose Simulator (SEEMS) for small-scale CHANS, with particular focus on biological conservation hotspots areas under developmental pressures. The model highlights a microeconomic basis tailored for research objects of the kind featuring heterogeneous agents with partial rationality, and integration of various mechanisms of two-way human-nature interaction such as ecological succession, and farmland fallowing. These features, together with merits in low data and computational requirements and convenient extendibility, make SEEMS an easy-to-apply approach in CHANS modeling. A case study in China's Wolong National Reserve for Giant Pandas not only validates the model's capacity of accurately simulate the real-world demographic, social, economic, and ecological situations, but also demonstrates nonlinear outcomes that might not otherwise emerge in statistical models. Subsequent studies may benefit from these features of SEEMS to investigate theoretical problems in the human-nature relationship in biological conservation hotspots, or practical ones regarding conservative policy-making in such areas. [ABSTRACT FROM AUTHOR]

• GF-1 and GF-6 remote sensing data have potential for wetland change detection. • Spatial-temporal attention method can identify information changes in cultivated land to wetland areas. • Sanjiang National Nature Reserve has large wetland restoration areas located near water sources. • The results of the study have important implications for the restoration and sustainable development of wetlands. Wetlands are important ecosystems, and detecting changes in wetlands plays a very important role in the management of wetland resources. Therefore, we selected Sanjiang National Nature Reserve as the study area and proposed a method in which bi-temporal GaoFen (GF) remote sensing data was combined with a spatial–temporal attention neural network (STANet) model, coupled with the selection of spectral variables. We used the bi-temporal images from GF-1 and GF-6 and compared three band selection methods, Relief F, principal component analysis, and RGB combination, and two STANet-based change detection methods (BAM: basic spatial–temporal attention module and PAM: pyramid spatial–temporal attention module) to improve the change detection of the wetland restoration. The results show that the accuracy of wetland change detection is related to different combinations of spectral variable selection and STANet models. The combination of Relief F feature selection and the BAM model led to the highest accuracy of the wetland change detection, 71.72 % for F1-Score and 76.92 % for MIou. The vector results of the change detection statistics show that the area of the Sanjiang National Nature Reserve cultivated lands converted to wetlands is 46.05 km2. This study implies that the STANet method has the capacity of detecting complex wetland restoration. Red, Bule, NIR and Red Edge1 bands of GaoFen data can provide effective information in the detection of changes in wetlands. The results of the study can be used as a reference for rational planning of wetland restoration, seeking a balance between cultivated lands and wetlands, which is important for the sustainable development of wetland. [ABSTRACT FROM AUTHOR]

• A frame of conservation effectiveness evaluation for mangrove nature reserves was proposed. • Results indicate most NMNRs was effective for conserving mangroves in China during 1987–2019. • The improvement to the conservation effectiveness was largely attributed to the implementation of protection activities. • Remote sensing-based method provides efficient evaluation of conservation effectiveness for NMNRs. Mangroves are high-productive ecosystems and globally protected. Establishing nature reserves aimed at counteracting the negative effects of anthropogenic activities is one of the most pivotal approaches to conserve mangrove ecosystems. Evaluation of the conservation effectiveness for mangrove nature reserves is thus indispensable for making knowledge-based conservation policies and funding-decisions by government and managers. In this study, using composited Landsat images by the Google Earth Engine cloud platform and object-oriented deep learning classification method, the land cover maps of national mangrove nature reserves (NMNRs) in China were obtained from 1987 to 2019. The systematic evaluation of conservation effectiveness for each NMNR was conducted by landscape metrics and an entropy weight model. Combined with the dynamics in mangrove distribution, human interference intensity, and natural environment change, the driving force factors affecting the conservation effectiveness for NMNRs were investigated. The results show that the total mangrove area in all NMNRs increased 968.6 ha during the study period, a 21.8 % rate of increase. Except for one NMNR with a slight decline, the conservation of remaining NMNRs was considered effective with increase varied from 14.8 % to 87.5 % in the level of protective efficacy. The conservation effectiveness of NMNRs was affected by both anthropogenic and natural factors, while the improvement to the conservation effectiveness was largely attributed to the implementation of protection policies, such as reforestation engineering. Further direct or indirect challenges in mangrove conservation effectiveness, e.g., pollution, natural disasters, and exotic species invasion, still require close attention. This study provides an effective and efficient approach to quantify the conservation effectiveness of mangrove nature reserves, which would facilitate mangrove conservation and management in the future. [ABSTRACT FROM AUTHOR]

• Exploring the protection effect of national nature reserve based on ESFs analysis. • Comparisons include type and location differences in conservation effectiveness. • The establishment of nature reserve caused the spillover of human activities inside. • Policy changes have dynamic effects on regional ecosystem service trade-offs. The analysis of the protection effect from the perspective of ecosystem service function (ESF) is an important basis for proposing optimal management strategies in nature reserves. Aiming at the internal, external, and different types of nature reserves of the National Nature Reserve in the Qinghai-Tibetan Plateau from 1992 to 2015, this study used the InVEST model to analyze the dynamic changes in four key ESFs, including carbon storage, water conservation, soil retention, and habitat quality. Based on this, the protective effect of nature reserves was evaluated. The main conclusions were as follows: (1) From 1992 to 2015, the spatial distribution pattern of carbon storage, water conservation, soil retention, and habitat quality inside and outside National Nature Reserve in Qinghai-Tibetan Plateau is "high in the east and decreasing to low in the west". On the time scale, the stability inside the reserve was higher than that outside. (2) Among all types of nature reserves, the ESF of forest ecosystem nature reserves always ranked highest, and the ESF of desert ecosystem nature reserves ranked lowest. (3) During the 23-year period, the protection effect of ecosystem services inside National Nature Reserve was between 1.0821 and 1.0870, which was always higher than that of the outside areas. (4) The protection effect of the comprehensive ESF in forest ecosystem nature reserves ranked highest with a value of 1.3169. Although the protection effect of desert ecosystems is relatively weak, it has continuously increased from 0.8836 to 0.8955 over the 23-year period. Based on the changes in the ecological processes of nature reserves, exploring their protection effectiveness will help strengthen the comprehensive understanding of ecosystems in conservation research. The development of effective policies and management measures has had a positive effect on the adaptive adjustment of ecosystem service trade-offs. [ABSTRACT FROM AUTHOR]

• In over half of nature reserves, anthropogenic pressure has been eased. • Fractional vegetation cover increased in 3 out of 4 nature reserves. • The vegetation aggregation index showed a downward trend. • Habitat quality was negatively correlated with anthropogenic pressure. The increasing human impact on the global environment has led to biodiversity decline and species extinction. The establishment of nature reserves is recognized as the most effective way to minimize human disruption and curb continuing threats to the Earth's life support system. Many areas in the world are currently witnessing depopulation trends. How does anthropogenic pressure change within nature reserves in these areas? How will this change affect the quality of their habitats? As a typical depopulating area and a main distribution area of China's nature reserves, Northeast China is an ideal region for exploring these scientific issues. In this research, we mapped anthropogenic pressure and habitat quality within 93 nature reserves in Northeast China from 2000 to 2018 and explored their correlation. We found that in Northeast China—a typical depopulating area—the anthropogenic pressure within nature reserves has been greatly eased and the habitat quality has improved. Along with depopulation, the anthropogenic pressure in more than half of the protected area in Northeast China declined between 2000 and 2018. Net primary production increased in almost all nature reserves, and fractional vegetation cover improved in three quarters of nature reserves. However, the vegetation aggregation index showed a downward trend. The overall performance of the national nature reserves surpasses that of the local nature reserves. Pearson's correlation coefficient showed a statistically significant negative correlation between habitat quality indices and anthropogenic pressure categories. The highest negative correlation was observed between the vegetation aggregation index and land use intensity. Based on the propensity score matching approach, we classified nature reserves in Northeast China according to their conservation effectiveness relative to matched unprotected control sites. Finally, recommendations such as transferring governmental protection investment, broadening funding sources, and joining in international evaluation networks are proposed. [ABSTRACT FROM AUTHOR]

[Display omitted] • Interactions of 3 pheasants were studied using a new model based on long-term data. • And considered habitat filtering and indirect species interactions together. • Both positive and negative interactions existed among 3 pheasants. • Species interactions varied with habitat heterogeneity and stress levels in 11 years. As the lack of a general understanding of how interspecific interactions change along varying environmental gradients exists, predicting the response of ecological communities to habitat and climate change becomes an arduous task. Researchers generally assess interspecific interactions by investigating species co-occurrence patterns. However, habitat filtering and indirect interspecific interactions can interfere with interspecific interaction signals in co-occurrence data, and these two factors have rarely been considered jointly in previous studies. By using the Markov random fields model which can control the indirect interaction, based on the 11-year co-occurrence data, we analyzed the effects of environmental factors on the interaction of three sympatric pheasant species (Chinese Bamboo Partridge Bambusicola thoracicus , Sichuan Hill Partridge Arborophila rufipectu , Temminck's Tragopan Tragopan temminckii) in Laojunshan National Nature Reserve, China. To eliminate the interference of habitat filtering, we took the environmental change during the 11-year period as the environmental variable instead of the environmental spatial gradient commonly used in previous studies. We found that the positive interaction increased with the increase of temperature, and decreased with the increase of precipitation, and with the increase of EVI heterogeneity, the positive interaction increased and the negative interaction decreased. The results are consistent with the predictions of habitat heterogeneity hypothesis and stress gradient hypothesis. Our study provides an idea for the follow-up studies of how to eliminate the interference of habitat filtering and indirect interaction in interspecific interaction analysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biomass of mature Sonneratia apetala plantations increased largely with forest age. • However, their SOC sequestration was at a much lower rate comparing with biomass. • A literature review confirmed that biomass and SOC stock increased with forest age. • SOC stock was linearly correlated with biomass. Non-native Sonneratia apetala plantations have been widely recommended as part of China's mangrove reforestation and afforestation plans, partly due to their rapid carbon accumulation in biomass and sediments. Nonetheless, reviews of the available data estimating carbon dynamics in the S. apetala plantations reveal a lack of monitoring data concerning carbon dynamics for the mature planted mangroves. This study sought to quantify how biomass and SOC stocks of the mature S. apetala plantations varied with mangrove growth between 2012 (aged 19 years old) and 2019 (aged 26 years old) using a continuous monitoring method. The results show that total biomass, as well as tree height and stem diameter at breast height (DBH), increased significantly between 2012 and 2019, while tree densities of both mangrove canopy and understory layers decreased. However, there was no significant difference in SOC content/stocks between 2012 and 2019. This result about SOC change may be partly attributable to the relatively shorter monitoring time span and the slower accumulation rate of SOC in comparison with biomass. In addition, fine root biomass was positively correlated with SOC content and regulated the vertical distribution of SOC content. Regression analysis for China's S. apetala plantations found that biomass, tree height and DBH, and SOC stocks all increased with forest age. Moreover, SOC stocks were significantly positively correlated with biomass. This suggests that mangrove afforestation and reforestation can offer carbon-sink potential, but this should be confirmed by longer-term monitoring to further evaluate the SOC accumulation of S. apetala plantations over time. [ABSTRACT FROM AUTHOR]

[Display omitted] • A multi-dimensional perspective study about ecological security evaluation. • Improving the DPSIR model based on different dimensional characteristics. • Defining the driving force of affecting ecological security under interaction. • Identification of key factors affecting ecological security. Evaluating the ecological security status of National Nature Reserve (NNR) has become a critical issue because NNR plays important roles in environmental protection and socio-economic sustainable development. This study employed the Baishuijiang National Nature Reserve (BNNR) as an example to construct the evaluation index system of ecological security, which was improved by adding society, economy and environment characteristics into driving force, pressure, state, impact and response modules, developing a modified DPSIR model. In addition, a Geo-detector was used to identify the key factors and the driving mechanisms that affect ecological security status of the BNNR. The results showed that ecological security status of the BNNR was classified into the safe area and unsafe area, with 46.95 % and 53.05% of the total area of the BNNR, respectively. The safe area was mainly distributed in the central areas of the reserve, where the ecological security index was from 0.329 to 0.370, whereas the unsafe area was mainly distributed in margins of the reserve, where the ecological security index was under 0.329. A Geo-detector identified that the per capita natural forest protection compensation funds, Engel's coefficient, domestic waste treatment, adult illiteracy rate, annual household income, and poverty incidence rate were key factors, and further showed that interactions between the social factors and economic factors were the primary external driving force for ecological security in the BNNR. These results suggest that the modified DPSIR model from multi-dimensional perspective can be used to evaluate ecological security and reveal ecological security driving mechanism, which presents a possible pattern of evaluate the ecological security status of NNR. [ABSTRACT FROM AUTHOR]

Seed priming is a well-established method for promoting seed germination and seedling growth. For Carex schmidtii , as a critical target plant species for restoration of degraded tussock wetlands in Momoge National Nature Reserve (MNNR) in northeast China, improving seed germination is critical to its large-scale population restoration. We conducted laboratory experiments to assess the effects of priming reagents, their concentrations and their interactions on seed germination and seedling growth to explore the most effective reagent and its optimum concentration. Priming significantly promoted C. schmidtii seed germination and seedling growth but significantly differed under varying priming treatments. Priming with GA 3 (0.2 g·L−1) significantly enhanced seed germination rate, speed, potential, index, vigor index and shoot growth of C. schmidtii compared to control conditions. KNO 3 treatments significantly promoted root biomass, total biomass (0.1%) and root length (0.2%). Additionally, shoot diameter of each priming treatment was significantly from the control. In conclusion, priming with 0.2 g·L−1 GA 3 and 0.1–0.2% KNO 3 significantly stimulated seed germination and promoted C. schmidtii seedling growth. These findings advance our understanding of the effect of priming on C. schmidtii germination and seedling growth and provide technical support for tussock wetland restoration in MNNR. • Priming treatments significantly promoted the seed germination and seedling growth. • Priming with GA 3 (0.2 g·L−1) motivate germination activity, shoot length and biomass. • KNO 3 priming (0.1–0.2%) promoted the root length and dry matter production. [ABSTRACT FROM AUTHOR]

[Display omitted] • A management layer was integrated into a traditional pressure-state-response model. • The ecological environment improved and the ecological vulnerability index rose. • Severely and moderately vulnerable areas were located in western and central regions. • The correlation coefficient of attribute vectors was used for causal analysis. The Qinghai-Tibet Plateau is facing a crisis of ecological degradation against a background of global warming and the intensification of human activities. With the aim of evaluating the spatial and temporal distribution of ecological vulnerability, this study established a new comprehensive pressure-state-response-management (PSRM) model based on the differences in the relative importance of indicators in a vulnerability evaluation system in different regions. The factors influencing ecological vulnerability were determined by calculating the correlation coefficient between the ecological vulnerability index (EVI) and the potential impact factors. The results showed that the spatial distribution of EVI in the Tibet Autonomous Region varied significantly, gradually decreasing from southeast to northwest. The regional ecological environment gradually improved from 2000 to 2015 and the EVI score increased. Following the establishment of national nature reserves in 2005, the areas that were extremely vulnerable in 2000 (accounting for 53% of the total area) were transformed into severely vulnerable or moderately vulnerable areas. The proportion of non-vulnerable areas also increased from 3% in 2010 to 6% in 2015 as cities expanded. The correlation analysis among vectors showed that GDP, population density, the proportion of tertiary industry, education level and policy support were strongly correlated with the EVI. Human activity had a greater impact on the EVI in urban areas. Our study provides suggestions for more sustainable development pathways to reduce environmental pressure and protect the fragile ecological environment. The approach used here can provide technical support and references for the ecological assessment and restoration of other high-altitude zones in China or elsewhere in the world. [ABSTRACT FROM AUTHOR]

• A prioritization framework developed for fragmented saltmarsh patch restoration. • Patch connectivity-importance rank correlated within connectivity metrics group. • Unrestrictive prioritization strategy gave best connectivity restoration outcome. • Metrics considering stepping stone effects resulted in more connected landscape. • Total probability of connectivity is most recommended among all metrics tested. 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. [ABSTRACT FROM AUTHOR]

The West China Rain Zone (WCRZ; 25,000 km2) is a broad mountainous ecotone between the urbanized Sichuan Basin (SCB) and the rural Qinghai-Tibetan Plateau (QTP). The WCRZ is rich in biodiversity and may be influenced by the air pollutants transported from the SCB towards the QTP. As air pollution can cause adverse effects on ecosystem health, this study investigated the fluxes, ecological risks, and sources of sulfur and nitrogen deposition by using a source-oriented community multiscale air quality (CMAQ) model for the entire WCRZ and its constituent national nature reserves in 2015. Results indicate that for sulfur (75%) and nitrogen (70%), the majority of the WCRZ area had annual total deposition fluxes higher than their critical loads. In addition, the annual volume-weighted mean (VWM) total inorganic nitrogen (TIN) wet deposition concentrations in almost the entire WCRZ exceeded the standard for total nitrogen of surface water in protected areas (0.2 mg N L−1). This exceedance is detrimental for the headwater watersheds that have precipitation as their sole water source. In each of the national nature reserves (NNRs), the average annual total deposition fluxes ranged between ~12–38 (sulfur) and ~ 15–38 kg S(N) ha−1 a−1 (nitrogen). About 40–100% (sulfur) and 5–85% (nitrogen) of the areas have annual total fluxes higher than the corresponding critical loads. Furthermore, the average VWM TIN concentration of wet deposition in each WCRZ NNR is higher than 0.2 mg N L−1. Therefore, sulfur and nitrogen deposition likely pose severe risks to some important natural ecosystems in the WCRZ. Based on the source apportionment results, to reduce sulfur and nitrogen deposition in the WCRZ, both SCB and non-SCB emissions should be controlled. In addition, the agricultural NH 3 emissions and the industrial and power plant SO 2 and NO x emissions should be reduced by larger extents than that of other sectors. This study provides a basis for future atmospheric and ecological observations in the WCRZ. [Display omitted] • Average annual deposition flux of sulfur (S) was 29.6 kg S ha−1 a−1 in the WCRZ. • Average annual deposition flux of nitrogen (N) was 33.0 kg N ha−1 a−1 in the WCRZ. • S and N deposition fluxes exceeded the critical loads in >70% of the WCRZ area. • S and N deposition likely pose severe risks to the WCRZ national nature reserves. • Both SCB and non-SCB emissions should be controled to reduce S and N depositon. [ABSTRACT FROM AUTHOR]

• The LULC change features were the increase of forest and decrease of cultivated land. • Landscape ecological risk increased during 1986–2008 and declined during 2008–2015. • Human management intensities deeply affected landscape ecological risk in reserves. It is necessary to improve the ecological environment and keep ecological balance of nature reserves that have particularly important function on precious and endangered wildlife species conservation. Human activities give rise to the remarkable changes in land use/land cover (LULC) and further have an effect on the landscape and eco-environment in nature reserves. This study evaluated the landscape ecological risk based on LULC changes in Baishuijiang National Nature Reserve according to different management zones from 1986 to 2015. Results showed that the significant change characteristics of LULC were the increase of forest and the decrease of cultivated land from 1986 to 2015. The major LULC changes took place in the experimental zone, and there was 85.61 km2 cultivated land transferred to the forest. Generally, the ecological risk level was low, and the area percentages of the lowest and lower risk regions to the total area were all higher than 97% from 1986 to 2015. Moreover, the values of ecological risk were discrepant in different time, the order of that being 1986 < 2015 < 1995 < 2008. Combining the components of different ecological risk levels in every management zone, the ecological risk from low to high was the core zone, buffer zone, and experimental zone. The ecological risk tended to be aggregated in space during 1986–2008, and it was enhanced slightly from 2008 to 2015. This study focuses on Baishuijiang National Nature Reserve to provide assessment for environmental protection and ecological management in hope that the method can be applied to other national nature reserves in China. [ABSTRACT FROM AUTHOR]

Polybrominated diphenyl ethers (PBDEs) are the ubiquitous contaminants in the coastal wetlands, with high persistence and toxicity. Environmental behaviors of PBDEs in sediment-plant system is a hot research area, where much uncertainties still occurred in field environment. In this study, the sediments and Suaeda heteroptera were synchronously collected to investigate the bioaccumulation and translocation of PBDEs in Liaohe coastal wetland. Mean concentrations of PBDEs in sediments, roots, stems and leaves were 8.37, 6.64, 2.42 and 1.40 ng/g d.w., respectively. Tissue-specific accumulation of PBDEs were detected in Suaeda heteroptera , with predominant accumulation in roots. Congener patterns of PBDEs were similar between sediments and roots, demonstrating root uptake as the key pathway of PBDE bioaccumulation. The proportions of lower brominated congeners increased from roots to leaves, implying the congener-specific translocation. Meanwhile, the lower brominated congeners exhibited higher sediment-tissue bioaccumulation (AFs) and translocation factors (TFs) compared to higher brominated congeners in Suaeda heteroptera , further verifying their preferential translocation. AFs and TFs of PBDEs were both not correlated with their log K ow , which was inconsistent with those of laboratory studies, reflecting the complicated behaviors of PBDEs in field environment. This is the first comprehensive report on bioaccumulation and translocation of PBDEs within Suaeda heteroptera in Liaohe coastal wetland. Image 1 • PBDEs were first reported in Suaeda heteropteran from Liaohe coastal wetland. • Tissue-specific accumulation of PBDEs were detected in Suaeda heteropteran. • Root uptake was the key pathway for PBDE bioaccumulation in Suaeda heteropteran. • The lower brominated congeners preferentially translocated from roots to leaves. • PBDE bioaccumulation and translocation were not just depended on K ow in field study. [ABSTRACT FROM AUTHOR]

• Improve the accuracy of the model by using the fractional derivatives method. • Extract bands of the hyperspectral images for the soil salt content estimation. • Classify the samples into training set and testing set by the cluster analysis. • Eliminate non-soil pixels by the Multiple Endmember Spectral Mixture Analysis. Soil salinity is a common global environmental problem that severely restricts industrial, agricultural and human development. In Northwest China, soil salinity is a problem affecting the Lake Ebinur area and needs to be monitored and addressed. The use of optical remote sensing technology to for timely and accurate soil salinity monitoring has great potentials and can be crucial for industrial and agricultural development. Optical remote sensing technology is an important data source for monitoring of soil salinization because of its rich spectral information and high-resolution. Based on the HJ-1/HSI data of fractional derivative transformation, this paper calculated the parameters, such as the difference index (DI), normalized difference index (NDI), ratio index (RI) and salt index (SI), that can invert the spatial distribution of salinization and then calculates a particle swarm optimization support vector machine (PSO-SVM). These index parameters were used to invert the spatial distribution information of salinized soil to explore the influence of fractional derivatives on the estimation accuracy of the spatial distribution of salinized soil. The results showed the following: (1) The optimal model based on different fractional derivatives and exponential transformations was the DI transformation under the fractional derivative of 1.2-order. R2, RMSE and RPD were 0.66, 13.81 g/kg and 2.59, respectively. These data show that the model had a good prediction effect. (2) The application of fractional derivatives in the processing of hyperspectral images could highlight the spectral details of the images and enrich their pretreatment methods, which is of great significance for the inversion of the distribution of salinized soil by hyperspectral images. (3) In the lakeside area of Lake Ebinur, the soil is mainly saline to severely saline. In the northern mountainous region of Lake Ebinur, the soil is mainly non-saline soil to mildly saline soil. Finally, in the Kuitun riverbank area in the southeast of Lake Ebinur, the soils are mainly non-saline soils to mildly saline soils. The results of this study demonstrate the potential of spectral index optimization and prediction models to monitor soil salinization based on fractional derivatives. This technique highlights the spectral detail information and enriches the preprocessing methods of hyperspectral imagery, resulting in the mapping of the spatial distribution of the degree of soil salinization. This has practical importance for the prevention and control of soil salinization and its spatial extent in arid and semi-arid regions. [ABSTRACT FROM AUTHOR]

• A convenient scheme to determine diagnostic indicators is presented. • Improved object-based analysis has broad application prospects. • Homogenous vegetation response unit (HVRU)-based AGB inversion is developed. • Variable types, regression algorithms and research scales are discussed in modeling. • AGB inversion researches are extended on short vegetation species at fine scales. Quantification of aboveground biomass (AGB) from local and regional to global scales is significant for sustainable ecosystem management, and object-based analysis technique is attractive in AGB studies. This study extended the AGB inversion researches on short vegetation species at a relatively fine scale using a homogenous vegetation response unit (HVRU)-oriented analysis approach, and explored a convenient scheme to determine diagnostic indicators. In the meantime, spectral, structural and geographic indicators related to AGB were derived from multisource data to generate HVRUs using multiresolution segmentation technology; the utilities of different variable types, regression algorithms and research scales were further evaluated in HVRU-based AGB modeling to determine the diagnostic indicators. Results showed that, inversion accuracies based on mean variables were much higher than those based on texture variables. Partial least squares regression (PLSR) and support vector regression (SVR) provided similar accuracies, in general, SVR performed better in digesting texture variables and time consumption, while PLSR was more suitable for mean variables. Compared to spectral indicators alone, the introduction of non-spectral indicators weakened accuracies at the scale of 50; at the scale of 100, 150 and 200, integrating spectral and structural indicators significantly improved accuracies on the whole; additional geographic indicators showed adverse impacts in most cases. The optimal inversion accuracy with R 2 cv of 0.83, RMSE cv of 0.20, RPD of 2.34 was realized based on the mean variables of spectral and structural indicators at the scale of 150 using PLSR, furthermore, FVC, OSAVI and (1/R 742nm)'' contributed much more than other indicators in modeling. Effective indicators excavated in this study could be directly applied for AGB survey in Yancheng National Nature Reserve and similar areas in China's coastal mudflat. The HVRU-based analysis approach fusing the advantages of multisource data and multiresolution segmentation technology has broad application prospects especially for research objects which are hard to quantify. [ABSTRACT FROM AUTHOR]

• Calculated Ecological Environment Quality Index by principal component analysis. • Analyzed the spatial auto-correlation of Ecological Environment Quality Index. • Explored the relation of Ecological Environment Quality Index and four indicators (greenness, wetness, heat, and dryness). Remote sensing technology can objectively and quantitatively evaluate spatial-temporal change of ecological environmental quality. This paper uses images from Landsat5 Thematic Mapper (TM) in 2007 and Landsat8 operational land imager (OLI) in 2013 and 2016 to extract indicators such as greenness, wetness, heat, and dryness that reflect the ecological environment quality of arid area. The principal component analysis (PCA) used the evaluating ecological environment quality of the Ebinur Lake Wetland National Nature Reserve to explore the characteristics of spatial differentiation for ecological quality in environment as indicated in the remote sensing ecological index (RSEI). The results showed that the greenness and wetness have positive effects on the ecological environment while the heat and dryness have negative effects. Wetness has a greater impact on the ecological environment than the other three indicators. The proportion of RSEI of degeneration, invariability, and improvement were 20.57%, 42.98%, 36.44%. Thus, the ecological environment had improved. The improved area in 2016 was once located in bad level in 2007. The ecological environment had degraded in the southern part of the lake. The value of Moran's I showed an increased trend first and then decreased. The value of Moran's I increased in 2013, in comparison with 2007, indicating a strong positive correlation and certain internal connection between the ecological environment qualities in the study area. The spatial distribution was clustered rather than random. In comparison with 2013, the auto-correlation in 2016 was relatively weak, an indication that the spatial distribution was random and disperse. The area of High-High (HH) mostly reached to the significant level of 0.05 in 2007 and then to 0.01 in 2013 and 2016. This study offered important results and information for ecological environment protection and region planning. [ABSTRACT FROM AUTHOR]