Ecological Restoration Strategies Research Articles

Temporal variations in reactive oxygen species in biofilms of submerged macrophytes: The key role of microbial metabolism mediated by oxygen fluctuations

Reactive oxygen species (ROS) play a crucial role in the biogeochemistry of aquatic environments, yet their occurrence and accumulation in the biofilm of submerged macrophytes have been poorly documented. Herein, we first investigated the light-dark cycling fluctuations of biofilm microenvironment and the temporal variations of a representative ROS (O2•−) during biofilm succession on the macrophyte leaves and subsequently quantified the photochemical processes in biofilms. The sustained production of O2•− exhibited a distinct rhythmic fluctuation from 32.49 ± 0.56 μmol/kg to 72.56 ± 0.92 μmol/kg FW, which simultaneously fluctuated with the dissolved oxygen, redox potential, and pH, all driven by the alternating oxic-anoxic conditions of biofilms. The intensities of O2•− and ROS firstly increased and then decreased throughout biofilm succession. The O2•− concentrations in biofilms from different waters followed the order of rural river water > landscape lake water > aquaculture pond water, and the leaf photosynthesis and microbial community played a key role. ROS production was significantly associated with Actinobacteria, Proteobacteria and Bacteroidetes, with contributions of 44.6%, 32.8%, and 15.2%, respectively. Partial least squares path modeling structural equation analysis showed that ROS production in leaf biofilms was mainly related to the microenvironment and microbial metabolism. These findings will facilitate the development of ecological restoration strategies in aquatic environments.

Ecological Restoration in the Loess Plateau, China Necessitates Targeted Management Strategy: Evidence from the Beiluo River Basin

Vegetation on the Loess Plateau, China, has continuously improved thanks to certain ecological restoration (ER) strategies, including the integrated soil conservation project that began in the late 1970s and the “Grain for Green” project that began in the 1990s. The experience of these strategies in different geomorphological regions is of great value to ER worldwide. In this study, the evolution of the land-use transition (LUT) pathway and ecosystem service value (ESV) in four geomorphological regions of the Beiluo River Basin was analyzed using geo-informatic Tupu and the equivalent factor method with data from 1975 to 2015. The results indicated that, from 1975 to 2015, the proportion of forestland in the Beiluo River basin increased by 18.27%, while the areas of shrub, grassland, cultivated land, and water decreased by 1.03%, 0.16%, 18.23%, and 0.26%, respectively. In the past 40 years, the overall ESV of the basin increased by USD 3.209 billion (54.16%). The landform, vegetation cover, LUT, and ESV analysis indicated that the main ecological functions of the loess hilly and gully (LHG), loess plateau gully (LPG), rocky mountain (RM), and terrace and plain (TP) regions are soil and water conservation (SWC), SWC and food production, regulation and food production, respectively. ER projects enhanced the main ecological function of individual regions. In detail, the transition of “cultivated land → grassland” enhanced SWC function in the LHG region, and the transition of “grassland (shrub) → forestland” enhanced the regulating services of the RM and LPG regions. Moreover, the transition of “cultivated land to grassland” did not seriously lower the food production services of the TP and LPG regions, owing to the increase in grain yield per unit area. However, there were alternating transitions between cultivated land and ecological land types, implying a game between the peasant households’ demands and the ER strategies. Conflicting demands between local households and the public necessitate precision ER strategies, including land planning, ecological compensation, training and employment for local residents, etc.

Soil erodibility for water and wind erosion and its relationship to vegetation and soil properties in China's drylands

Drylands with fragile socio-ecological systems are vulnerable to soil erosion. China's drylands face the dual threat of water (WAE) and wind erosion (WIE). To mitigate soil erosion in drylands, China has implemented numerous ecological restoration measures. However, whether vegetation and soil have different effects on soil erodibility for water erosion (soil erodibility, K) and wind erosion (soil erodible fraction, EF) in drylands is unclear, hindering decision makers to develop suitable ecological restoration strategies. Here, we conducted a large-scale belt transect survey to explore the spatial variation of K and EF in China's drylands, and examined the linear and nolinear effects of aridity (aridity index), vegetation (fractional vegetation cover and below-ground biomass), and soil properties (bulk density, total nitrogen, and total phosphorus) on K and EF. The results showed in China's drylands that the K ranges from 0.02 to 0.07, with high values recorded in the northern Loess Plateau and the eastern Inner Mongolia Plateau. The EF ranges from 0.26 to 0.98, and shows longitudinal zonation with higher values in the east and lower values in the west. Aridity has a negative linear effect on K and an inverse U-shaped nonlinear effect on EF. Aridity can affect K and EF by suppressing vegetation growth and disrupting soil properties. However, K and EF had different responses to some vegetation and soil variables. K and EF had opposite relationships with soil bulk density, and EF was significantly affected by fractional vegetation cover, while K was not. Overall, the effects of aridity and soil properties on soil erodibility were more pronounced than those from vegetation, whose effect on soil erodibility was limited. This study provides relevant information to support reducing soil water and wind erosion by highlighting the hotspot areas of soil erodibility, relevant for implementing vegetation restoration and soil conservation measures in drylands.

Ecological restoration strategies of rock-soluble stone desertification regions under the background of big data and the Internet of Things

As the focus and difficulty of global ecological governance, rock-soluble graphite ecological issues have been plagued by the research and exploration of ecologists for many years. This article studies the current development status of rock-soluble graphite. Features and laws targeted implementing the ecological restoration strategies of rock-soluble graphite regions under the background of big data and the Internet of Things. By establishing a mathematical analysis model of the total ecological assets, the theoretical research on the restoration process and means of ecology. In the past 20 years, the southwest region’s ecological improvement and governance situation has been summarized and analyzed, and the key aspects and main contents of ecological restoration are analyzed and demonstrated.

Risk analysis of rainfall erosion on upland adjacent to riparian zone of the Three Gorges Reservoir

The Three Gorges Reservoir (TGR) is an artificial riparian ecosystem and influenced on its soil erosion. However, the probability and magnitude of the erosion on upland adjacent to riparian zone and its impacts on the TGR are still unclear. In this research, we determined the relationship between minute-scale rainfall erosivity and soil erosion from three replicated upland bare plots (5 m × 20 m for each) in Zhong County, southwest of China, from 2017 to 2019 (short-term), and estimated the rainfall erosion based on the daily-scale rainfall erosivity from 1992 to 2015 (long-term). We performed generalized extreme value (GEV) modeling to quantify three risk elements (scenario, probability-magnitude relation, consequences) and predicted the erosion risks. The results indicated that, over the short-term, wet season increased the average runoff depth and soil loss by a factor of 1.6 (p < 0.01) and 1.4 (p < 0.01), respectively. Low and rare rainfall erosivity (5 years < return period ≤ 20 years) caused the erosion event with relative low occurrence probability (return period > 5 years) to dominantly contribute the total erosion (>65%) in dry season. Common and normal rainfall erosivity (return period ≤ 5 years) caused the common erosion events (return period ≤ 2 years) to contribute nearly 50% of the total erosion in wet season. Over the long-term, extreme rainfall erosivity (1621 MJ·mm·ha−1·h−1) in dry season was predicted to be more effective on upland erosion, but a uniform pattern of erosion contribution of incremental rainfall return periods was estimated in wet season. Our findings improve the understanding of the uncertainty of upland-surface hydrologic processes in the TGR, and could provide useful risk management or ecological restoration strategies for the soil and water conservationists.

Spatial and temporal variations of vegetation cover and its influencing factors in Shandong Province based on GEE.

Economic development has rapidly progressed since the implementation of reform and opening up policies, posing significant challenges to sustainable development, especially to vegetation, which plays a crucial role in maintaining ecosystem service functions and promoting green low-carbon transformations. In this study, we estimated the fractional vegetation cover (FVC) in Shandong Province from 2000 to 2020 using the Google Earth Engine (GEE) platform. The spatial and temporal changes in FVC were analyzed using gravity center migration analysis, trend analysis, and geographic detector, and the vegetation changes of different land use types were analyzed to reveal the internal driving mechanism of FVC changes. Our results indicate that vegetation cover in Shandong Province was in good condition during the period 2000 to 2020. The high vegetation cover classes dominated, and overall changes were relatively small, with the center of gravity of vegetation cover generally shifting towards the southwest. Land use type, soil type, population density, and GDP factors had the most significant impact on vegetation cover change in Shandong Province. The interaction of these factors enhanced the effect on vegetation cover change, with land use type and soil type having the highest degree of influence. The observational results of this study can provide data support for the policy makers to formulate new ecological restoration strategies, and the findings would help facilitate the sustainability management of regional ecosystem and natural resource planning.

Ecological network-based food web dynamic model provides an aquatic population restoration strategy

Aquatic ecosystem restoration is a crucial aspect of ecological management. However, current research tends to concentrate on single factors, such as water quality or biodiversity, rather than ecological restoration strategies based on the characteristics of an ecological network system. Due to the large number of parameters to be considered, the latter approach presents still full of challenges in practical implementation. This study introduces a food web dynamic model that can guide and facilitate aquatic ecological network restoration. The model calculates the network-based interaction relationships of species in the food web, predicting the changes in ecosystem structure and function. We test our food web model by conducting a case study. The food web considered 9 kinds of species nodes, 12 links, and 1 uncertain predator–prey interaction. Our model simulations presented a strong correlation with the measured data (R2 = 0.837). We performed sensitivity analysis on 12 parameters and also conducted link prediction analysis, which revealed that there was no predator–prey relationship between species A and N (A + N = 0). By comparing population dynamics under 3 conditions, we determined that the mass reproduction of nonnative species and the population decline of native species were both related to indirect food web interactions. Finally, we comprised 27 scenarios, including fishing and stock enhancement approaches, to predict the potential restoration effects. The results showed that the fishing approach was more effective in removing alien species when the fishing frequency was shorter. It was also found that selecting catches and releasing native or endangered species back into the environment (F4, F5, F6, and F12) was necessary. On the other hand, the stock enhancement approach was concluded to be effective in increasing the number of native species as long as the frequency of enhancement was high (per 1 year, S1, S2, and S3). However, it was found to be challenging to rely on this approach to reduce the population of nonnative species. This research will enhance the previous studies in terms of (a) including whole species interactions in the ecological network; (b) considering the influence of abiotic factors, such as water quality, terrigenous carrying capacity, shoreline substrate, and hydrological connection in our model; and (c) coupling significant parameters in ecological restoration practices. This research will provide a valuable tool for managing aquatic ecological networks and decision-making suggestions for determining restoration schemes in complex aquatic food webs.

Land use/cover changes and subsequent water budget imbalance exacerbate soil aridification in the farming-pastoral ecotone of northern China

Understanding the impact of human activities on changes in surface dryness/wetness is crucial for the sustainable development of terrestrial ecosystems. The farming-pastoral ecotone of northern China (FPENC) is experiencing obvious soil aridification under ongoing climate change. The impacts of human activities on cropland and grassland vary. However, how human activities affect soil aridification in terms of cropland and grassland remains unclear. To fill this knowledge gap, this impact mechanism based on the remote sensing retrieval of aridification index and the construction of water budget mismatch index(WMI) is quantified in this study. The results demonstrate a strong spatial consistency between the WMI and the trend of soil aridification. In particular, the trend of soil aridification in the west-central and northeastern areas remained unmitigated where the WMI was less than one. This was due to a more dramatic increase in evapotranspiration (ET) (+64.7 mm) compared to precipitation after subtracting runoff (Pi) (+53.9 mm) in the decade between 2001 and 2019. Under the same climatic conditions, croplands had higher crop evapotranspiration and lower soil water storage capacities (WSC) than grasslands, resulting in the aridification intensity of croplands being 1.3 times greater than that of grasslands. Moreover, irrigation exacerbated the depletion of regional groundwater and intensified soil aridification in adjacent drylands and grasslands within a radius of at least 2000 m. These findings provide a scientific foundation for comprehending the mechanism of aridification, developing ecological restoration strategies, and promoting regional sustainable development in the FPENC.

Practice of ecological remediation and restoration in plain river network -- a Case Study of Gehu Lake in Changzhou, China

This study provides a design diagram which involves a series of pragmatic strategies for ecological remediation and restoration of plain river networks in the Yangtze River Delta. The design diagram is composed of two stages: the first concerns the reduction of pollutants, including those from non-point sources, point sources, and river sediments; the second, the restoration of the biological habitat, including the riparian zone and aquatic habitat. A case study of Gehu Lake was used as an example for the implementation of the suggested design diagram, and further suggestions were provided for the improvement of remediation work in plain river network areas. This research provides valuable insights into the methods of ecological restoration, and demonstrates the potential for multidisciplinary collaboration to help improve the environmental health of plain river networks.

Tree islands enhance biodiversity and functioning in oil palm landscapes

In the United Nations Decade on Ecosystem Restoration1, large knowledge gaps persist on how to increase biodiversity and ecosystem functioning in cash crop-dominated tropical landscapes2. Here, we present findings from a large-scale, 5-year ecosystem restoration experiment in an oil palm landscape enriched with 52 tree islands, encompassing assessments of ten indicators of biodiversity and 19 indicators of ecosystem functioning. Overall, indicators of biodiversity and ecosystem functioning, as well as multidiversity and ecosystem multifunctionality, were higher in tree islands compared to conventionally managed oil palm. Larger tree islands led to larger gains in multidiversity through changes in vegetation structure. Furthermore, tree enrichment did not decrease landscape-scale oil palm yield. Our results demonstrate that enriching oil palm-dominated landscapes with tree islands is a promising ecological restoration strategy, yet should not replace the protection of remaining forests.

Coastal Wetland Restoration Strategies Based on Ecosystem Service Changes: A Case Study of the South Bank of Hangzhou Bay

A unique variety of wetlands known as coastal wetlands that connect terrestrial and marine ecosystems is crucial to reducing and adapting to climate change as well as the advancement of human culture. However, the coastal wetland ecosystem is currently in danger as a result of the increasing intensity of human activity, and wetland restoration and reconstruction have garnered a lot of interest. The differentiated ecological restoration strategies based on ecosystem service change analysis can provide a reference for the effective management and sustainability of coastal wetland ecosystems. The InVEST model and ArcGIS were used to analyze the spatiotemporal changes in ecosystem services before and after the implementation of coastal wetland restoration policies based on remote sensing image data, meteorological and soil data, etc. The ecological restoration pattern of coastal wetlands was divided, and the corresponding ecological restoration strategies were proposed in this study. The following are the results: (1) there are still many wetlands that have been converted to non-wetlands following the implementation of the wetland restoration policy, and the ecosystem services as a whole exhibit a rising and then falling trend, with a rise from 2005 to 2015, a fall in 2015 due to the creation of Hangzhou Bay New District, and a slight improvement to 2020. Among them, the water yield increased continuously, the carbon storage fluctuated, and the habitat quality did not improve significantly. (2) The hot spots of ecosystem services were concentrated in the south and southeast of the study area, with no obvious cold spots. (3) By comprehensively analyzing the changes and spatial patterns of ecosystem services, the coastal wetlands on the south bank of Hangzhou Bay were divided into an ecological conservation zone, a green development zone, and an ecological restoration zone at the township level, and corresponding optimization strategies were proposed. The results can provide a reference for the fine-grained and differentiated management of regional ecosystem services.

Water and wind erosion response to ecological restoration measures in China's drylands

Soil erosion is the most severe form of land degradation threatening terrestrial ecosystems globally. Drylands with fragile ecosystems are particularly sensitive to soil erosion. China's drylands face the threat of soil erosion by wind and water. Currently, more studies need to be focused on wind and water erosion response to ecological restoration measures at monthly resolution in these areas. This is key to understanding ecological restoration measures' effectiveness under changing environments. Here, we assessed the monthly water and wind erosion in China's drylands from 2001 to 2020 using the G2 model and revised wind erosion equation (RWEQ). The Sequential linear regression slopes (SeRGS) explored water and wind erosion intensities. We also discuss the mitigation benefits of two ecological restoration measures, afforestation and grassland restoration. The results showed that water and wind erosion in China's drylands is mild (47.35%) and slight (58.76%). Water erosion increased between 2001 and 2020, while wind erosion decreased. At the monthly level, a higher water and wind erosion rate occurred from April to June and February to March, respectively. Water erosion dominated 50.64% of the China's drylands, while wind erosion was the most critical form of erosion in 47.88%. Nevertheless, the erosion pattern in China's drylands is changing. The average mitigation benefits of afforestation on water and wind erosion were −61.12% and −57.05%, respectively, and the average mitigation benefits of grassland restoration on water and wind erosion were −57.05% and 7.95%, respectively. This study can help managers identify the best ecological restoration strategies to mitigate land degradation in drylands.

Characteristics of Soil Microbial Community in Different Habitats in the Process of Ecological Restoration of Haifeng Wetland in Guangdong

Soil microorganisms can respond to changes in wetland ecosystem quality and functional evolution sensitively. To explore the changes and response mechanisms of soil microorganisms under ecological restoration measures, the characteristics of the soil microbial community and their influencing factors were analyzed using high-throughput sequencing technology in four different habitats (revegetation area, native vegetation area, tidal creek, and tidal flat) during the ecological restoration process in Haifeng wetland in Guangdong. The results showed that:soil physicochemical properties of the four different habitats were significantly different; the contents of TC, TN, TOC, and TK in the tidal creek were significantly higher than those in the other habitats; and the contents of TC, TN, and TP in the revegetation restoration area were significantly higher than those in the tidal flat. The EC values in the tidal creeks and tidal flat were significantly higher than those in the revegetation area and the native vegetation area. The diversity index and abundance of soil bacteria in the tidal creek were the highest, and those in the vegetation restoration area were significantly higher than those in the bare flat. The archaea in the tidal creek were significantly more complex than those in the other three habitats, and the fungal community diversity index and abundance in the native vegetation area were significantly higher than those in the other areas, which had the most complex community structure. TN and TC were the main factors affecting the bacterial community, whereas TN and EC were the main factors affecting the archaea community, and pH, TN, and TP were the key factors affecting the fungal community. In conclusion, the planting of vegetation on the tidal flat increased the diversity and richness of the soil microbial community during the process of ecological restoration, indicating that it has resulted in positive feedback on ecological restoration so far. The results of this study can provide a theoretical basis for the selection of ecological restoration strategies for the tidal flat.

Diagnosis of Key Ecological Restoration Areas in Territorial Space under the Guidance of Resilience: A Case Study of the Chengdu–Chongqing Region

Territorial space ecological restoration is a significant way to map the development of “ecological priority, green, and low-carbon” and realize the goal of reducing carbon emissions. Based on the evaluation of the degree of urban ecological resilience restriction, this study aimed to diagnose the key areas of surface–line–point ecological restoration under the guidance of the resilience target by constructing a patch–corridor–matrix ecological network; then, the corresponding repair strategy was proposed. The results showed that (1) there was an obvious core–periphery structure in the resilience restriction intensity of the Chengdu–Chongqing region, showing a gradual decreasing trend from Chengdu and Chongqing to the surrounding cities; (2) the regional ecological network, including 17 ecological source patches and 33 potential ecological corridors, was identified; and (3) the diagnosed key areas of ecological restoration were composed of surface–line–point multiscale spatial morphology, including 7793.81 km2 of key areas of ecological source restoration, 380.39 km of key areas of ecological corridor restoration, and 29 key areas of ecological pinch point restoration. The construction of ecological restoration strategies with carbon neutralization as the core idea at different scales was realized. The research can provide a reference for scientifically identifying key areas of ecological restoration in territorial space, coordinating and planning major projects of ecological restoration, and optimizing the allocation of natural resources.

Ecological Risk Evaluation and Ecological Restoration Model of Mining in the Source Area of the Yellow River Basin

Finding out about the ecosystem damaged by mining development and carrying out ecological risk diagnoses are important prerequisites for formulating mine ecological restoration strategies. This study established an integrated approach to quantitatively analyze mining ecological risks by combining water conservation and biodiversity conservation ecosystem service functions with natural ecological conditions, and based on these, proposes appropriate mine ecological restoration strategies. Results show that: (1) A total of 14,874.80 hm2 of ecosystems were damaged in the Qinghai section of the Yellow River Basin, caused by mining excavation, crushing and hollow collapse, and of which 52.10% were located in national important ecological function areas and National Nature Reserves, which caused a decrease of the important ecosystem service functions of water conservation and biodiversity conservation in the area, and aggravated the ecological risks of the river source area; (2) The areas of high ecological risk and comparatively high ecological risk in the research area are 1,093,800 hm2 and 902,100 hm2, which accounted for 7.27% and 6.00% of the land area, respectively. Ecological risk hotspot areas are mainly distributed in the Qilian Mountains, Hehuang Valley, Sanjiangyuan and other key water systems and water sources; (3) According to the principle of “one mine, one policy”, we propose five mine ecological restoration models: ecological reconstruction, artificial assistance and protection and conservation, artificial assistance, protection and conservation and natural restoration. This study provides a reliable basis for exploring the status of mining ecological risk at the source of the Yellow River and scientifically carrying out ecological restoration and risk management.

An integral approach to environmental restoration in the face of climate change, cultural identity, and archaeological heritage: the case of Tzintzuntzan, Michoacán, México

[Introduction]: Conservation and restoration of the ecological and cultural heritage is a necessity given the current environmental crisis, in particular when considering the effects of climate change. This can be achieved through interdisciplinary research that allows the creation of strategies for restoring complex biocultural landscapes. [Objective]: To propose strategies for ecocentric, biocultural and productive ecological restoration in Tzintzuntzan (place of hummningbirds) a landscape dominated by precolumbian archaeological remains in the riverbanks of lake Paztcuaro, México, considering the expected effects of climate change. [Metodology]: A GIS was created with information about gthe socioenvironmental conditions of the study site, a climate change model was also elaborated for year 2050 and the loss of water lake water level was estimated. [Resultados]: From the present conditions of the vegetation, climatic modelling and the presence of archaeological remains we obtained that for the year 2050 most of the area (89%) of forests dominated by oaks and pines will have a climate appropriate for dry tropical vegetation. Considering the distribution of archaeological remains and the urban area we propose ecocentric, biocultural and production restoration strategies. [Conclusions]: A biocultural approach to restoration is desirable because it allows the recovery of ecological and cultural elements of the socioecosystem, with a emphasis in adaptation to climate change and the recovery of hummingbird habitat, being the hummingbirds the most important link between nature and culture in the region.

Monitoring ecological restoration of riparian forest: Is the applied nucleation effective ten years after implementation in the Pampa?

Ecological restoration is a process that helps restore a degraded, damaged, or destroyed ecosystem. Applied nucleation is considered a strategy that facilitates the development of vegetation, attracts dispersers, and, over time, tends to expand, coalescing into continuous forests. However, simply implementing restorative techniques is not enough, it is also necessary to monitor the process. Monitoring requires good ecological indicators, which is a challenge for ecological restoration. The present study aims to evaluate, through ecological indicators, the effectiveness of the applied nucleation for restoration of riparian forest. The study was carried out in the Serra do Sudeste, Pampa region, southern Brazil. Ecological indicators were analyzed in two areas of restoration: passive and active restoration. In the area under active restoration, paired plots were evaluated: intra-nuclei (inside the nuclei) and inter-nuclei (outside the nuclei). To assess natural regeneration, all regenerant shrubby and arboreal individuals taller than 30 cm were counted and taxonomically identified. The species were classified according to the dispersal syndrome. Shannon diversity indices and Pielou evenness were calculated. The canopy cover of nuclei and trees planted crown cover were evaluated. Ecological indicators were compared using Tukey’s test (p < 0.05). The results showed a significant difference between passive, intra-nuclei, and inter-nuclei restorations for the evaluated indicators, with higher averages for intra-nuclei, followed by inter-nuclei and passive restorations. It is concluded that the intra-nuclei plots showed an increase in richness, abundance, biotic dispersal syndrome, canopy cover, and soil cover by plant litter and arboreal species. The applied nucleation is an effective strategy for ecological restoration in the study region.

Differences between total amount of heavy metals and their occurrence form contents in the wastelands of a molybdenum mine area

In a single sample plot, the total amount of heavy metals in the soil could not necessarily reflect the contents of their effective states. This must be considered when attempting to determine the degree of soil heavy-metal pollution in an area. In the present study, the soil around the molybdenum mining area in Huludao, China, was surveyed and sampled to evaluate soil heavy-metal pollution using the Nemerow multifactor pollution index method. The Tessier continuous extraction method was used to analyze the distribution of heavy-metal forms’ and their content changes in the soil of this area. Thus, the bioactivity of heavy metals in the soil, the absorption of heavy metals by plants, and the distribution of heavy metals in plants were explored to provide data supporting the use of phytoremediation technology to treat the heavy-metal pollution in the molybdenum mining area and develop ecological restoration strategies for the area’s wastelands. The pollution index results indicate that heavy-metal pollution in the soil around the tailings pond is severe, mainly due to Pb and Zn heavy metals. Heavy-metal pollution in the surrounding land is mainly due to Cd and Zn. Content analysis of the heavy-metal forms/states in soils shows that exchangeable forms, which are most effective and toxic to plants, of the following metals are highest in the following areas: Cd, Cu, and Zn in the mountains around the stope; Zn, Mo, and Cu in the cultivated land around the dump; and Cd, Zn, and Mo in the cultivated land around the tailings pond. The pollution index analysis provides a basic overview of soil heavy-metal pollution across the entire mining area. However, content analysis of heavy-metal forms/states better reflects the relationship between the availability of heavy metals in the soil and the effectiveness of plants. Thus, the latter analysis can help ensure that phytoremediation strategies are adequately targeted, science-based, and effective.

Zoning for Spatial Conservation and Restoration Based on Ecosystem Services in Highly Urbanized Region: A Case Study in Beijing-Tianjin-Hebei, China

Ecosystem services are highly affected by human activities, especially in the fast-urbanizing regions. It is important that the regional development or urbanization strategy be implemented by maintaining or protecting the long-term provision ability of multiple ecosystem services. The spatial pattern of ecosystem services and zoning for spatial conservation and restoration are the preconditions of sustainable development. With the Beijing-Tianjin-Hebei (BTH) region as the research area, an approach for spatial zoning was proposed on the basis of the modeling results of key ecosystem services (water retention, soil retention, heat mitigation, and carbon storage). Our results show that the hot spots of ecosystem services are mainly in the north and the west at high altitudes and with large vegetation coverage, while the cold spots are mainly in the plain area of the southeast in the BTH region. In addition, the whole region is divided into five ecological zones: the ecological restoration zone, ecological transition zone, coastal ecological protection zone, soil and water retention zone, and ecological security shelter. Each zone has applied different strategies for ecological restoration and conservation. The results represent the spatial heterogeneity and major functions in different zones, and they can provide planning guidance for supporting the coordinated development of the BTH region.

Variation of soil physicochemical properties of different vegetation restoration types on subtropical karst area in southern China.

To carry out differentiated ecological restoration activities and formulate appropriate environmental conservation strategies for karst regions, it is essential to investigate the impact of ecological restoration and forest management strategy differences on soil properties. The karst region in Xiangxi, Hunan province, China was selected as the study site. Here, we determined soil physical and chemical differences in soil profiles of karst areas with ecological restoration activities. The results showed that (1) the soil properties showed a significant difference between the restoration vegetation and uncultivated land, especially in soil physical properties. The soil moisture conversion coefficient (83.0%) and soil bulk density (1.37g/cm3) of Liriodendron chinense (Hemsl.) Sarg reached the highest value among 12 vegetations. 2) The topsoil was more sensitive to ecological restoration. Soil physical properties in the topsoil samples from the forest management areas were significantly higher than uncultivated lands (P < 0.05). (3) Redundancy analysis showed that the soil chemical content differed significantly among the types of forest vegetation restoration and different soil layers. Among the nutrients analysis, Mg, Zn and K were the main factors affecting soil properties in the rocky desertification areas. Therefore, our results recommend planting the broadleaved deciduous forest as the preferred forest among three different forest types to enhance soil fertility and water conservation functions, especially in subtropical karst areas ecosystems, which provided for making scientific forest restoration management in the karst region.