Regional Ecological Risk Assessment Research Articles

Disease risk of the foliar endophyte Colletotrichum from invasive Ageratina adenophora to native plants and crops

The disease risk driven by foliar fungi asymptomatically infecting invasive plants has rarely been determined. In this study, we selected 44 foliar Colletotrichum endophytes isolated from the invasive plant Ageratina adenophora that are phylogenetically closely related to the C. gloeosporioides complex, C. boninense complex, C. orchidearum complex, and C. acutatum complex and evaluated their potential virulence and ability to transmit spores to native plants and cash crops both in vitro and in vivo. We verified that some foliar endophyte Colletotrichum strains adversely affect the leaf and seed germination of native plants and cash crops. Some strains reduce the growth and yield of tomato (SL) (Solanum lycopersicum) and pepper (CA) (Capsicum annuum) plants and even cause the death of strawberry (FA) plants (Fragaria ananassa). Moreover, we confirmed that A. adenophora leaves could horizontally transmit Colletotrichum to surrounding crop plants in vivo. Therefore, a high abundance of Colletotrichum asymptomatically associated with A. adenophora leaves might increase disease risk in surrounding native plants and cash crops. Our results provide a new perspective for regional ecological risk assessment of invasive plants and prevention of economic plant diseases in the invaded range.

Potential ecological risk assessment based on loss of ecosystem services due to land use and land cover change: A case study of Beijing-Tianjin-Hebei region

Ecosystem services (ESs) bridge the gap between human wellbeing and ecosystem processes. Land use and land cover change (LUCC) affect ecosystem services by altering the structure and function of ecosystems. Beijing-Tianjin-Hebei (BTH), one of the most developed urban agglomerations in China, is subject to intense LUCC that affects ESs while increasing the regional ecological risk (ER). Therefore, to achieve the coordinated development of socioeconomic and ecological quality, there is an urgent need to establish a regional ecological risk assessment (ERA). ESs were introduced into the ERA to clarify their ecological significance and to compensate for the deficiencies of the traditional ERA. In this study, the ERA utilizes key ESs as endpoints to assess potential ER through a new framework by multiplying the probability of LUCC by the resultant loss of key ESs. We found that cultivated land was the most dominant outflow type and built-up land was the predominant inflow type. From 2020 to 2030, there is a greater possibility of changes in cultivated land, forest, grassland, and built-up land as well as in relatively stable water bodies and unused land. Overall, ESs show a positive trend. The overall potential ER was relatively minimal, with a significant northwestern spatially concentrated characteristic of high values. This study helps understand the potential development process of ERs and provides a scientific basis for risk management.

Regional ecological risk assessment through the application of production-living-ecology land use function indicators: a case study of the eco-economic zone of Yellow River Delta.

To date, land use structure information has been employed extensively for ecological risk assessment (ERA) purpose in regional/landscape scales; in contrast, land use function (LUF) information-based ERA research is still scarce. Therefore, it is necessary to carry out more ERA case studies in macroscale with the help of pertinent LUF indicators. As an important way to construct production-living-ecology LUF indexes, this study employs the weighted stacking method and related economic statistical data for regional ecological risk assessment (RERA) purpose within Yellow River Delta High-efficiency Eco-economic Zone (YRDHEZ), China. This YRDHEZ-RERA research pointed out that (1) it was rational to use a series of economic statistical data to more comprehensively and precisely characterize regional production and living function grades in YRDHEZ. (2) The Yellow River Delta had lower agriculture and non-agriculture production functions, whereas the rest of the zone had higher production functions. (3) Most people lived in the south part, whereas north coastal zone had very low population density; the east part had higher per capita disposable income of urban/rural households than that of west. (4) The south part of the zone had higher production/living functions and integrated ecological risk source intensity than those of north coastal zone, whereas the coastal zone had higher ecology function, eco-environmental vulnerability, and final integrated ecological risk than those of inland region. As for regional ecological risk management, establishing nature reserve with strict spatial governance for coastal/estuarine wetlands and coordinating production/ecology functions of coastal salterns/breeding ponds are relevant feasible measures.

Regional ecological risk assessment of the Yellow River Delta High-efficiency Eco-economic Zone, China, with respect to human production–living disturbance

Regional ecological risk assessment of the Yellow River Delta High-efficiency Eco-economic Zone, China, with respect to human production–living disturbance

Regional ecological risk assessment based on multi-scenario simulation of land use changes and ecosystem service values in Inner Mongolia, China

Regional ecological risk assessment (ERA) is an important means towards sustainable regional development. Yet, existing ERA approaches often fall short of characterizing ecological processes as dynamic processes involving uncertainty. Using Inner Mongolia, a high ecological risk area in China, this study employed a framework for regional ERA that considers ecosystem service value (ESV) and four scenarios of future land use patterns to understand its regional ecological risk. The spatially explicit risk assessment method was implemented by a model combining multi-criteria evaluation (MCE), cellular automata (CA), and Markov chain to predict future land use/cover of 2030, an adjustment-based equivalence factor method to assess the ESV in each scenario, and Sharpe Index to assess regional ecological risk. The results show the following. First, the overall ESV increases from 2020 to 2030 under all but the socio-economic development (SED) scenarios considered in this study. Second, the overall regional ecological risk of Inner Mongolia is high in the central region and low in the east, north, and west regions. The low ecological risk areas account for the largest areal proportion in the ecosystem services protection (ESP) and natural development (ND) scenarios, while the medium ecological risk areas are the largest under SED. However, some low ecological risk areas are converted into medium ecological risk in ecological and socioeconomic balance scenario (ESB) scenario. Third, NDVI is the driving factor with the strongest explanatory power for the regional ecological risk in Inner Mongolia, followed by mean annual precipitation and temperature. The present study applied a framework for regional ERA that explicitly considers spatial heterogeneity and uncertainty, which can be useful for guiding decision-making for ecological risk control and the planning of the land use of ecosystems.

Identifying the spatio-temporal dynamics of regional ecological risk based on Google Earth Engine: A case study from Loess Plateau, China

Located in the middle reaches of the Yellow River Basin, the Loess Plateau is one of the typical eco-fragile regions in China, which has complex and diverse ecological problems and is in urgent need of comprehensive ecological governance and restoration. Ecological risk assessment as a method to quantify complex ecological risks can provide decision-makers with quantification and visualization of risk scenarios, which can serve the ecological protection and restoration of the Loess Plateau. Pre-processed and acquired through GEE, the multi-source and long-term remote sensing data are introduced to facilitate the efficiency of risk monitoring. There are few studies about GEE-based spatio-temporal ecological risk monitoring in the Loess Plateau. Therefore, a regional ecological risk assessment system from the perspective of risk sources, risk receptors, and exposure responses has been established to visualize and quantify the spatial heterogeneity of regional multi-perspective ecological problems at a 1 km-grid scale from 2001 to 2020. Meanwhile, multi-aspects spatial statistics and trend analysis are taken to identify the spatial and temporal characteristics. The results demonstrated that the comprehensive ecological risk of the Loess Plateau presented a decreasing trend from 2001 to 2020, which is mainly due to the improvement of vegetation conditions. Spatially, the low-risk pixels are primarily in the east and west, while the high-risk pixels mainly locate in the north central and northwest. From 2001 to 2020, the high-risk pixels in the central region decrease, and the high-risk pixels are concentrated in the northwest. In general, the ecological risks is significantly spatially heterogeneous, varying according to latitude and longitude, land cover, topography. Identifying grid-based dominant risks and trends provides decision-makers with accurate risk control and helps propose appropriate countermeasures.

Regional ecological risk assessment of chemical industry stress under China's coastal development strategy

Governments and scholars are taking a closer look at risk assessment of areas developing chemical industries because of the repeated occurrence of chemical explosion accidents along coastal regions. The paper constructs an indicator system for Jiangsu Province based on three dimensions: risk source strength, receptor vulnerability, and risk prevention capability. It comprehensively evaluates the risks under stress from the chemical industry since the implementation of the coastland development strategy. The results show that a first rise in and then a decline in comprehensive risk along the coast of Jiangsu Province could be observed from 2007 to 2017. As a whole, the risk of contamination was dispersed, while locally, it accumulated and gradually shifted to areas along the river and adjacent coastal areas. High-risk areas are mainly distributed in chemical industry clusters. Risk sources continue to intensify with the increase in heavy chemical industry clusters. Generally, receptor vulnerability was high in the west, low in the east, high in the north and south, and low in the middle. The Tongyu River, Sheyang River, coastal wetlands, and canals in Nantong are among the most vulnerable areas. There is still a weak overall situation, with a pattern of ‘high-low-high’ staggered distribution from south to north, even though the risk prevention capacity is growing steadily.

Multi-Scenario Landscape Ecological Risk Simulation for Sustainable Development Goals: A Case Study on the Central Mountainous Area of Hainan Island.

The sustainable development goals (SDGs) of the United Nations are focused on regional development and ecological security. Based on these SDGs, quantitative regional landscape ecological risk assessment is significant to realize regional sustainable development. This study took the central mountainous area (CMA) of Hainan Island as the research area, and combined SDGs and a patch-generating land-use simulation (PLUS) model to analyze multi-scenario land-use change and landscape ecological risk simulation. The study results show that the low ecological risk areas are located in the central hinterland of the CMA, and the high ecological risk areas are located on the northern and southern edges, with strong disturbances from human activities. The construction land in the CMA expanded drastically from 2010 to 2018, mainly invading forestland and grassland, leading to landscape fragmentation, which was the main cause of the increased ecological risk in the CMA landscape. The future multi-scenario simulations for SDGs show that under the scenario of natural development and economic development, the construction land and water area will significantly expand and the forest land will be dramatically reduced. Under the ecological protection scenario, the expansion of construction land will be restrained, and the area of forest land will increase. The results showed that the landscape ecological risks in the three simulated scenarios would be higher than in 2018, but the increase in the landscape ecological risks under the ecological protection scenario would be relatively slight. Forest land plays an essential role in maintaining the ecological security of the CMA. The expanding construction land in the CMA has led to landscape fragmentation and increased ecological risk. Therefore, it is necessary to protect the forest land in the CMA. In addition, construction and development should be limited in high-risk areas. Although the adoption of the ecological conservation scenario favors regional sustainability, it is still necessary to improve ecological protection policies such as ecological compensation to ensure the realization of other SDGs.

Analytical methods used in regional ecological risk assessment of potentially toxic elements (PTEs) in wetlands

Sulak alan ekosistemleri çok sayıda fauna ve flora türüne yaşam ortamı sunan, aynı zamanda insanların faydalandığı önemli doğal kaynak değerleridir. Son yıllarda artan antropojenik etkiler sulak alanlarda PTE kaynaklı ekolojik bozulmaya ve buralardan çeşitli yollarla faydalanan insanlar üzerinde sağlık risklerine neden olmaktadır. Bu nedenle, sulak alanlarda ekolojik bozulma ve sağlık riski analizleri yapmak için analitik metotlar geliştirilmiştir. Zenginleşme faktörü (Enrichment factor-EF), Kontaminasyon faktörü (Contamination factor-CF), Modifiye kontaminasyon derecesi (Modified contamination degree-mCd), Jeoakümülasyon indeksi (Geoaccumulation index-Igeo) ile elementlerin doğal ve antropojenik kaynakları tespit edilmektedir. Modifiye ekolojik risk indeksi (Modified ecological risk-mER) Modifiye potansiyel ekolojik risk indeksi (Modified potential ecological risk-mPER), Kirlilik yük indeksi (Pollution load index-PLI), Toksik risk indeksi (Toxic risk index-TRI), Modifiye edilmiş risk oranı (Modified hazard quotient-mHQ), Ekolojik kontaminasyon indeksi (Ecological contamination index-ECI) ve Kontaminasyon ağırlık indeksiyle (Contamination severity index-CSI) ekolojik risk değerlendirmesi yapılmaktadır. Kanserojen olmayan sağlık risklerinin tespiti için Tehlike indeksi (Hazard index- HI) ve Tehlike oranı (Hazard quotient-HQ), kanser riski tespiti için Yaşam boyu toplam kanser riski indeksi (Lifetime cancer risk index-LCR) hesaplanmaktadır. PTE’lerin ortak kaynaklarını tanımlamak ve taşınma süreçlerini tespit etmek için çok değişkenli istatistiksel analizler ve Coğrafi Bilgi Sistemleri’ne dayalı mekânsal analizler kullanılmaktadır. Bu çalışmada, yukarıda belirtilen metotların kapsamlı bir değerlendirmesi yapılmıştır.

Regional Scale Risk to the Ecological Sustainability and Ecosystem Services of an African Floodplain System.

The Phongolo floodplain is one of southern Africa's most important systems. In this study, we carried out a regional scale ecological risk assessment to evaluate the risk of multiple stressors associated with the use of the aquatic resources in the floodplain to selected social and ecological endpoints representing its sustainability. The floodplain has undergone significant changes as a result of the impacts of multiple stressors. This includes high risk of impact and threatened sustainability between the Pongolapoort Dam and the Ndumo Game Reserve (NGR). This compares to relatively low risk to the maintenance of the endpoints within the NGR. The reserve provides a protection and refuge function for regional biodiversity maintenance and ecosystem sustainability processes. In the study a range of scenarios were considered and demonstrate that the system will respond to protection measures and or increased resource use options. Should flood reductions or water quality pollution drivers continue on increasing trajectories, the condition of the Phongolo River and floodplain will probably deteriorate into an unacceptable, unsustainable state. Removal of the protection services of the NGR would result in an unsustainable ecosystem and loss of ecosystem services for regional vulnerable African communities. Additional evidence should be obtained from monitoring and research to refine, validate, and update the assessment in an adaptive management context. The risk assessment framework approach implemented in the Phongolo floodplain can contribute to the management of other floodplains ecosystems and the sustainability management of social and ecological attributes and processes of these important ecosystems.

Regional ecological risk assessment of multi-ecosystems under the disturbance of regional pole-axis system: a case study of the Tongjiang-Fuyuan region, China.

In this study, the regional pole-axis system (urban/town areas and multi-level roads) where human production and living activities are concentrated was recognized as the main regional ecological risk source space; in contrast, multi-type ecosystems, such as wetland/waterbody and forestland and cropland with significant ecosystem service provisioning function, were identified as the main regional ecological risk receptor spaces. Based on this regional ecological risk source/receptor space division scheme, related ecological risk source/receptor indicators were chosen to characterize the spatial heterogeneities of human activities and ecological capital distribution within the study area. Among them, the Defense Meteorological Program Operational Line-Scan System (DMSP/OLS) nighttime light intensity and normalized density of multi-level roads data were employed as regional ecological risk source indicators, whereas the ecosystem service value of multi-ecosystems was employed as a regional ecological risk receptor indicator. Then, combined with regional eco-environmental vulnerability indexes, a regional ecological risk assessment framework was established and practiced in the Tongjiang-Fuyuan region, a wetland-concentrated area of the Sanjiang Plain. The results showed that (1) the DMSP/OLS nighttime light intensity data matched the distribution of regional urban/town areas and farms well, and it was reasonable to employ this dataset to represent the scope of regional production-living land space; (2) regional ecological space, such as wetlands and forestlands, had a higher ecological risk grade; (3) because of their higher human disturbance severity and ecological vulnerability level, regional settlement points (county seats and farms) had the highest ecological risk, whereas agricultural land space, occupying the largest area of the region, had the lowest ecological risk level; and finally, (4) in terms of proportion, the low, medium, high, and very high risk grades accounted for 71.66%, 17.13%, 8.43%, and 2.78% of the study area, respectively. Based on the results, a series of approaches, which can be adopted to promote regional sustainable development of the Tongjiang-Fuyuan region, were discussed, such as spatial governance of wetlands by establishing nature reserves, coordination of economic exploitation activities within forestlands, setup of a spatial expansion boundary of urban/town/farm areas, and tradeoffs between production and ecology functions of croplands.

Regional assessment of human-caused ecological risk in the Poyang Lake Eco-economic Zone using production-living-ecology analysis.

In this study, based on the regional land-use risk space division (regional ecological risk source/receptor space identification) using production–living–ecology analysis, three spatial function indexes, i.e., production, living, and ecology function indexes, were proposed for regional ecological risk assessment (RERA) with respect to human disturbance. The first two indexes can be regarded as regional ecological risk source indexes, whereas the final index can be regarded as a regional ecological risk receptor index. Using an artificial assignment method based on the land-use types and Defense Meteorological Program Operational Line-Scan System (DMSP/OLS) nighttime light intensity data, these three spatial function indexes were effectively manifested. By incorporating these indexes with eco-environmental vulnerability proxies, an RERA framework was established and applied in the Poyang Lake Eco-economic Zone (PLEZ), which is an ecological-protection and economic-development coordination-oriented region in China. The results suggest that (1) the DMSP/OLS nighttime light intensity data correlated well with the spatial distribution of regional urban/town areas; consequently, it was reasonable to use this dataset for representing regional production-living function space (urban/town area). (2) Overall, the forestlands and winter waterbodies of Poyang Lake were in the high-risk grade, and so did the Nanchang City construction land area; in contrast, the final risk levels of winter wetlands and croplands were relatively low. (3) Owing to the highest human disturbance (including both production and consumption human activities) and eco-environmental vulnerability level, urban/town areas such as Nanchang City had the highest final risk grade. (4) The low, medium, high, and very high-risk grades accounted for 21.22%, 39.53%, 36.31%, and 2.94% of the region, respectively. I believe that the proposed land use function indexes will be helpful in conducting human-caused RERA research in the future. Furthermore, the assessment results can provide a scientific basis for regional ecological risk management within the PLEZ.

Risk Assessment of Water Quantity and Quality Stressors to Balance the Use and Protection of Vulnerable Water Resources.

In developing regions of the world, valuable and vulnerable water resources are being used excessively. Through water resource development, multiple water quality, flow, and other stressors threaten the sustainable use and protection of these resources. Few attempts have been made to evaluate the synergistic effects of multiple water quality and flow stressors to socioecological attributes of systems that we care about in integrated water resource management. Regional scale ecological risk assessments evaluate the probable negative effects of multiple stressors, affecting dynamic ecosystems on multiple spatial scales. The present study demonstrates how multiple water quality, flow, and other stressors that cumulatively affect the sustainability of the lower Thukela River, South Africa, can be evaluated using the relative risk model, Bayesian network (RRM-BN) approach. This risk assessment facilitated the establishment of minimum water quality and flow requirements to maintain the sustainability of this system and make water resource use and protection trade-off decisions. In this case study, the risk of 10 water resources use and protection scenarios were evaluated in a regional scale ecological risk assessment of the socioecological attributes of the lower Thukela River. In addition we evaluated the consequences associated with these scenarios based on risk pathways of multiple sources, stressors, and receptors to endpoints that represent the sustainable vision of multiple stakeholders of the system. The outcomes of the present study have contributed to new evidence to improve the water resource use efficiency and protect important resources of the lower Thukela River, to ensure sustainability. Integr Environ Assess Manag 2021;17:110-130. © 2020 SETAC.

Regional Ecological Risk Assessment with Respect to Human Disturbance in the Poyang Lake Region (PYLR) Using Production–Living–Ecology Analysis

In the regional ecological risk assessment (RERA) research with respect to human disturbance, risk source–receptor identification and corresponding indicators selection are of great importance. In this study, three regional function indexes, i.e., production function index, living function index, and ecology function index, were produced and incorporated into the human-caused RERA research. Among them, the former two indexes can be considered as human disturbance indexes, namely risk source indexes, whereas the last one can be deemed as ecological risk receptor index. Based on related economic statistics and land-use data, which are commonly used approaches for data acquisition, these three spatial function indicators were calculated separately. Incorporated with eco-environmental vulnerability proxies, this RERA framework was realized finally. With the Poyang Lake Region as a case study, the proposed RERA model was practiced to examine its effectiveness in expressing and revealing spatial heterogeneities of regional ecological risk source, risk receptor, eco-environmental vulnerability, and final integrated risk level. The results showed that: (1) the main winter waterbody of Poyang Lake was mainly in the grade of medium risk (grade 2), whereas the north connection part between the lake and the Yangtze River, and the south semi-closed sub-lakes, such as the Junshan Lake, were in high-risk group (grade 3); (2) the west part of the region had a higher human-caused risk level on the whole than that of the east, especially those in Jiujiang and Nanchang cities, in accordance with higher production and living human-disturbance level there; (3) owing to near to the downtown of cities, the wetlands and forestlands within the scope of Nanchang and Jiujiang cities, such as Nanjishan Wetland National Nature Reserve in Nanchang City and Lushan Mountain Forest in Jiujiang City, all had high final risk level (grade 3); (4) in terms of proportion, the low-, medium-, high-, and very-high-risk grades accounted for 47.27%, 33.01%, 13.56%, and 6.16% of the region, respectively. The three regional function indexes adopted in this study, characterizing spatial heterogeneity of regional ecological risk with respect to human activities, will be helpful for related research in the future. Besides, the assessment results could provide scientific basis for regional ecological risk management and then sustainable development of the study area.

Study on application of regional ecological risk assessment during the development and utilization of Chu Island

Taking natural disaster risk problems in the uninhabited island ecosystem as the main research object and combined with the features of uninhabited island ecosystem, regional ecological risk assessment was carried out with the relative risk model (RRM) taking an exemple of Chu island. According to ‘Weihai Chu island protection and utilization planning (2011~2020)’, the study area was divided into three risk areas, which are key protected area, basic facility area and ecological tourism area. Birds, sea cucumbers and their habitat as the receptors for Chu island ecological risk assessment was selected, and combined with the regional sources of risk occurrence probability, the range and intensity, storm surge, drought and cold wave were the main risk sources in the region. The exposure response relationship of “risk source—stress—habitat—ecological end point” in each risk area was analyzed. We pointed out: (1) in the development and utilization process of Chu island, storm surge is the most influential source of risk in the region, and its influence is far higher than drought and cold wave; (2) the island land resources, especially the vegetation, affected by the risk source is the largest, followed by water and the tidal flat; (3) As the two main functional areas in the development and utilization process of Chu island, the relative risk value of basic facility area and ecological tourism area, which is 1.05 and 0.97 respectively, is larger than key protection area, and its relative risk value is 0.5.

Integrating ecosystem services value and uncertainty into regional ecological risk assessment: A case study of Hubei Province, Central China

In the context of rapid urbanization, ecosystem services (ES) losses pose serious threats to sustainability. How to assess ecological risk based on ES value (ESV) has become an urgent problem for sustainable urbanization. However, existing regional ecological risk assessment frameworks ignore important elements, such as the assessment endpoint and uncertainty, weakening their reliability and practicability. In this study, a regional ecological risk assessment framework integrating ESV and uncertainty was proposed by introducing a classical financial indicator, the Sharpe Ratio. We take Hubei Province, Central China as a case and implemented the spatially explicit risk assessment approach based on the methods of the Markov–logistic–CA model, adjusted-based equivalent factor evaluation model, and geographic information system. The results showed that the distribution of expected ecological returns and corresponding uncertainties at county level had a remarkable spatial heterogeneity, and the assessed ecological risk index in Eastern and Western Hubei was higher than that in Central Hubei, indicating that counties in Central Hubei are the priority areas for ecological risk control. Moreover, the expansion of built-up land had the most significant effect on regional ecological risk. This regional ecological risk framework can well integrate the assessment endpoint and dynamic processes of ecological risk. Our assessment framework has potential practical value for ecological risk control and land use planning on ecosystems.

Regional Ecological Risk Assessment of Wetlands in the Sanjiang Plain with Respect to Human Disturbance

Characterization of the intensity of regional human disturbances on wetlands is an important scientific issue. In this study, the pole-axis system (involving multi-level central places and roads) was recognized as a proxy of direct risk to wetlands stemming from human activities at the regional or watershed scale. In this respect, the pole-axis system and central place theory were adopted to analyze the spatial agglomeration characteristics of regional human activities. Soil erosion and non-point source (NPS) pollution, indicating the indirect effect of human activities on wetlands, were also considered. Based on these human disturbance proxies, which are considered regional risk sources to wetlands, incorporated with another two indicators of regional environment, i.e., vulnerability and ecological capital indexes, the regional ecological risk assessment (RERA) framework of wetlands was finally established. Using this wetland RERA framework, the spatial heterogeneity of risk grades within the Naoli River Basin, a typical concentrated wetland region in the Sanjiang Plain, was analyzed. The results showed that (1) high- and very high-risk source intensity areas displayed a ring-shape distribution pattern, which reflected the influence of the regional pole-axis system; (2) owing to their high ecological capital value per unit area and vulnerability level, the wetlands had the highest risk grade, as did central places (i.e., those areas where county seats and administration bureaus of farms were located). In terms of proportion, the low-, medium-, high-, and very high-risk areas accounted for 72.0%, 16.8%, 10.1%, and 1.1% of the study area, respectively. The identification and classification of risk sources to wetlands that are related to human activity at the watershed scale could provide clear perspectives in order to reduce severe risk sources to these areas, especially those Ramsor Convention-appointed sites of international importance. Moreover, the assessment framework used in this paper will provide a helpful reference for related research in the future. Finally, the new management guidelines proposed in this paper will be beneficial for lowering the ecological risk level of wetlands at the watershed or regional scale for the Sanjiang Plain or other wetland-concentrated regions.

Effects of rapid urbanization on ecological functional vulnerability of the land system in Wuhan, China: A flow and stock perspective

Exploring how rapid urbanization affects ecological functional vulnerability is a key issue in regional ecological risk assessment. This paper proposes a complex network approach to explore the response of ecological functional vulnerability to different urbanization scenarios from the perspective of stock and flow for the case study area of the Wuhan City in China. The paper aims to (1) establish a theoretical framework to explain how the urbanization process degrades ecological functions of the land system from a flow and stock perspective, (2) evaluate stock and flow changes of ecosystem service value triggered by land use change, and (3) explore the impact of different urbanization scenarios and different management costs on ecological functional vulnerability by combining two indicators, i.e., ecosystem service value change and ecological load entropy. Our results for Wuhan reveal that (1) non-ecological flows or degraded ecological flows are responsible for the increase in ecological functional vulnerability, (2) the total ecosystem service stock of the land system had slightly increased during 1990–2015, contributing to an enhanced ecological flow, (3) the critical points for maintaining the proper functioning of the land system are 80% or higher for cropland and 40% or higher for lake. These findings can provide critical references for the sustainable management of urban land system in Wuhan and other major cities in China. This study also suggest that the combination of ecosystem service value change and ecological load entropy can be used to comprehensively assess ecological functional vulnerability.

Regional distribution characteristics and ecological risk assessment of heavy metal pollution of different land use in an antimony mining area – Xikuangshan, China

Mining activities have introduced various heavy metals and metalloids to surrounding soil environments, causing adverse impacts to the ecological environment system. The extremely high concentration of various heavy metals and metalloids make the Xikuangshan (Hunan, China) an excellent model to assess their ecological risk. In this study, the soil samples from 26 locations of different land use methods in four areas (smelting area, road nearby ore, mining area, and ore tailing area) in Xikuangshan with different levels of various heavy metals and metalloids (Sb, As, Pb, and Cd) were analyzed; in addition, the index of geo-accumulation and the potential ecological risk index were used to evaluate ecological risk. The results showed that the average contents of Sb, As, Pb, and Cd in all soil samples were 4368.222 mg·kg−1, 40.722 mg·kg−1, 248.013 mg·kg−1, and 40.941 mg·kg−1, respectively, implying serious contamination of compound pollution of heavy metals in soil. The concentration of heavy metals in soil among smelting area, road nearby ore, mining area, and ore tailing area showed significant distribution characteristics of region because different mining activities such as smelting, mining, transportation, and stacking caused different pollution intensity. Moreover, the contents of Sb in soil samples decreased successively in residue field, wasteland, forestland, sediment, grassland, and vegetable field, and the contents of Sb in vegetable-field and ecological restoration grassland were relatively low, which indicate that the method of grassland ecological restoration is an effective method to control antimony pollution in soil. The results of ecological risk assessment showed that the antimony mining area was seriously polluted by Sb, As, Pb, and Cd, and had strong ecological risk, and Sb and Cd were the most important pollution factors, which indicated that the pollution of Sb and Cd should be a major concern of relevant departments of environment and health.

Ecological risk assessment of cities on the Tibetan Plateau based on land use/land cover changes – Case study of Delingha City

Land use/land cover and its change is a certain reflection of the interaction of natural factors and human activity in regional ecological environment, and the change of land use/land cover also affects the regional ecological process. Among regional ecological assessments, the landscape ecological risk assessment by land use/land cover changes is a regional ecological risk assessment method that is based on spatial pattern perspectives. The research on typical ecological fragile areas that respond strongly to global change focuses on coastal zones, wetlands and transition zones between cropping areas and nomadic areas; however, there are no related studies on the Tibetan Plateau. This study proposed an ecological risk assessment on Delingha City on the Tibetan plateau by using RS (remote sensing) and GIS (geographic information system) methods Based on land use/land cover variations in Delingha City during the periods 1986–2000 and 2000–2015, regional ecological risk changes were analysed to provide scientific bases for the ecological protection of cities on the Tibetan Plateau. The results indicated that: 1) From 1986 to 2000, major land use/land cover changes took place in the south of the city; in general, grassland was converted into farmland. From 2000 to 2015, the spatial distribution of land use changes was chaotic; however, the land use changes in the south were more concentrated and significant. 2) More than half of Delingha City fall under low ecological risk zones, which are mainly located in high-altitude mountainous area in north Delingha. High ecological risk areas are mainly located in the low-lying and flat landscapes in the south. 3) During the research period, the significant decrease of highest- and high-risk zones and considerable increase of low-risk zone indicate an improvement of the overall ecological environment in Delingha City through 1986–2015.