Micro-agents' perception of landscape services and their multi-level driving influences in the headwater area of the Qiantang River, China.

Landscape services are an important basis for maintaining regional ecological security patterns, environmental health, and sustainable socio-economic development. As an important link between regional ecosystems and socio-economic development, micro-agents' production and life as well as their cognition and perception of landscape services notably impact the maintenance of multi-functional landscape development. This paper examines 9 rural communities in different areas and different development types in the headwater area of the Qiantang River in China, China's national key ecological functional area, in a typical case study. Based on farmer interviews and household surveys, this paper explores the changes of micro-agents' diversification perception of landscape services from 2010 to 2020. A multiple linear regression method is used to construct an index model of agents' perception of diversification of landscape services and to analyze the driving factors influencing changes. The results showed that (1) from 2010 to 2020, the micro-agent perception index of the diversity of farmland, forest, garden, and grassland landscape services increased by 0.46, 0.43, 0.67, and 0.51, respectively. Among them, the micro-agents' diversified perception of forest, farmland, garden, and grassland landscape services decreased in sequence. (2) From 2010 to 2020, in regard to the importance and vulnerability of landscape services, the difference between the perception levels of farmland landscape support services and grassland landscape regulation services in the agricultural production core area was the largest. In management and rationality perception of landscape services, the difference in the perception between grassland landscape service ecological and economic development areas was the largest. (3) Individual and family characteristics are important factors affecting the diversification perception of landscape services, while the natural environment and resource endowment impose negligible influences. Environmental policies only affect the diversification of grassland perception. The research results can provide a reference for maintaining regional landscape services, improving the well-being of micro-agents, and promoting the enhancement in ecological services and regional collaborative development.

Multi-functional identification of social-ecological landscape in ecologically fragile areas under the background of regional transformation development.

To realize the coordinated development of regional economy, society, and ecosystem is the ultimate goal of economic development and ecological protection in ecologically fragile areas. The multi-functional identification of socio-ecological landscape in ecologically fragile areas is helpful to alleviate the practical contradictions and conflicts faced by the region, and to better realize the optimal allocation of regional resources and the formulation of rational regional land management and planning strategies. This study takes Mizhi County, the most prominent and representative area of the ecologically fragile areas of the Loess Plateau, as the research area. The three dimensions of the ecosystem, social system, and production system were used to construct a landscape multi-functionality identification and evaluation model. A comprehensive identification method for the landscape multi-functionality evaluation, dominant-secondary function recognition, and dominant-secondary obstacle function recognition were carried out to realize the recognition of the landscape multi-functionality. The results were the following: (1) The identification of the landscape multi-functionality through multi-objective optimal decision making with limited scheme for the determination of regional functions should follow the optimal decision rule. (2) The multi-function comprehensive identification method for the landscape could be used to scientifically identify the landscape multi-functions in the ecologically fragile areas. (3) The multi-functions of the social-ecological landscape were obvious. An area with an extreme value was prominent and presented a state of aggregation. The spatial difference between the dominant and secondary functions (obstacle functions) was strong, and the degree of interdependence between functions was high. This study provides a scientific reference for landscape optimization management in the ecologically fragile areas of the Loess Plateau.

[Distribution Characteristics, Ecological Risks, and Source Identification of Heavy Metals in Cultivated Land Under Non-grain Production].

The purpose of this study was to explore the distribution characteristics and potential ecological risks of soil heavy metal pollution of cultivated land under non-grain production. Taking a typical area around Hangzhou Bay as an example, 254 topsoil samples (0-20 cm) of cultivated land were collected, and the content of eight soil heavy metals in four different cultivated land use types, including grain, seedlings, vegetables, and fruits, was analyzed. The ecological risk was assessed by the Nemerow pollution index and the potential ecological risk index, and the PMF model was used to identify the source of soil heavy metals in the study area. The results showed that the average contents of As, Cr, Cd, Cu, Hg, Ni, and Zn were all higher than the soil background value, except for Pb, but were lower than the national risk control standard for soil contamination of agricultural land. Non-grain production had a significant impact on the accumulation of heavy metals in soil. The content of heavy metals in nurseries and orchards was relatively high, followed by vegetable fields, and the lowest in grain fields. The Nemerow index showed that the cultivated land in the study area was in a light pollution level as a whole, and the single-factor pollution risks of Hg, Cd, and As were relatively high. The potential ecological risk levels of heavy metals in different cultivated land use types were:nurseries>orchards>vegetable fields>grain fields. The PMF results showed that the main sources of soil heavy metals in the study area were mixed sources of industrial emissions (36.8%), natural parent material sources (28.4%), atmospheric deposition sources (21.4%), and agricultural activity sources (13.4%). In conclusion, the increase in the application of chemical fertilizers and pesticides was the direct reason for the increase in soil heavy metal content caused by non-grain production of the cultivated land, whereas the industrial and mining emissions and atmospheric deposition accelerated the increase in soil heavy metal content in the study area.

Trade-offs between economic benefits and environmental impacts of vegetable greenhouses expansion in East China.

Greenhouse vegetable cultivation (GVC) has become a global issue in agricultural land use in recent years. While the use of GVC brings considerable economic profits, it has significant environmental impacts, with a risk of threat to sustainability. To make sound development and management strategies, it is necessary to characterize the trade-offs between the benefits and costs of GVC expansion. This study focuses on the expansion of GVC in East China, taking Xiaoshan County as a case study. Remote sensing techniques are used to detect the spatial patterns of GVC expansion from 2005 to 2015; then, field surveys and empirical models are employed to assess the environmental impacts of greenhouse gas (GHG) emissions and plastic waste. Lastly, monetary analysis is used to evaluate the trade-offs between the environmental costs and economic gains caused by GVC expansion. The results show that GVC has expanded rapidly from 2005 to 2015 in Xiaoshan County. The GVC expansion has significantly increased GHG emissions and plastic waste from cultivated land. Both the economic benefits and environmental costs of GVC expansion show an increasing tendency throughout the study period. It denotes that economic benefits can compensate for environmental costs of GHG emissions and plastic waste brought by GVC, but the long-term damage to the quality and environmental conditions of cultivated land is still underestimated. We finally propose four major policy implications to achieve a win-win scenario between economic profitability and cultivated land protection associated with GVC.

Integrated analysis of urbanization-triggered land use change trajectory and implications for ecological land management: A case study in Fuyang, China.

Land use change under rapid urbanization can drastically change terrestrial ecological conditions. This study presents an integrated analysis of land use dynamics and the resultant ecological impacts on sustainable development over the past 25 years (1990-2015) in response to urban development. Remote sensing and geographic information system techniques were employed to examine the spatiotemporal trajectory of land use changes. Based on the analysis of the equivalent factor table for land use types and ecosystem services value (ESV), the value of ecosystem services was calculated in the case study of Fuyang, China. Correlations were identified between ESV and a family of landscape fragmentation metrics. The results showed that the area affected by land use changes represented 33.35% of the total study area and caused a 31.74 million US$·a-1 decrease in ESV from 1990 to 2015. The ESV was spatially imbalanced and generally low in urban areas. Ecological plans for cropland reforestation and urban green projects were effective in slowing ESV losses while urban areas rapidly developed. In addition, total ESV was negatively correlated with edge density (ED), patch density (PD), landscape shape index (LSI), and Shannon's diversity index (SHDI) but positively correlated with aggregation index (AI), suggesting that landscape fragmentation had an adverse impact on the overall ESV in Fuyang. Therefore, sustainable land use planning must be integrated with landscape patterns to provide useful guidance regarding the spatial regulation of a given area to protect and improve ecosystem services.

Spatiotemporal Variability of Soil Nitrogen in Relation to Environmental Factors in a Low Hilly Region of Southeastern China.

Soil total nitrogen (TN) plays a major role in agriculture, geochemical cycles and terrestrial ecosystem functions. Knowledge regarding the TN distribution is crucial for the sustainable use of soil resources. This paper therefore aims to characterize the spatiotemporal distribution of soil TN and improve the current understanding of how various factors influence changes in TN. Natural characteristics and remote sensing (RS) variables were used in conjunction with the random forest (RF) model to map the TN distribution in a low hilly region of southeastern China in 1979, 2004 and 2014. The means and changes of TN in different geographic regions and farmland protection regions were also analyzed. The results showed that: (1) the TN showed an increasing trend in the early periods and exhibited a decreasing trend from 2004 to 2014; (2) the geographic and RS variables played more important roles in predicting TN distribution than did the other variables; and (3) changes in the fertilization and crop planting structure caused by soil testing and formulated fertilization techniques (STFFT-Soil Testing and Formulated Fertilization Techniques) as well as farmland protection policies influenced the spatiotemporal variability of TN. Evidently, more attention should be focused on improving the quality and soil fertility in the surrounding low mountainous areas.

A Comparative Assessment of the Influences of Human Impacts on Soil Cd Concentrations Based on Stepwise Linear Regression, Classification and Regression Tree, and Random Forest Models.

Soil cadmium (Cd) contamination has attracted a great deal of attention because of its detrimental effects on animals and humans. This study aimed to develop and compare the performances of stepwise linear regression (SLR), classification and regression tree (CART) and random forest (RF) models in the prediction and mapping of the spatial distribution of soil Cd and to identify likely sources of Cd accumulation in Fuyang County, eastern China. Soil Cd data from 276 topsoil (0-20 cm) samples were collected and randomly divided into calibration (222 samples) and validation datasets (54 samples). Auxiliary data, including detailed land use information, soil organic matter, soil pH, and topographic data, were incorporated into the models to simulate the soil Cd concentrations and further identify the main factors influencing soil Cd variation. The predictive models for soil Cd concentration exhibited acceptable overall accuracies (72.22% for SLR, 70.37% for CART, and 75.93% for RF). The SLR model exhibited the largest predicted deviation, with a mean error (ME) of 0.074 mg/kg, a mean absolute error (MAE) of 0.160 mg/kg, and a root mean squared error (RMSE) of 0.274 mg/kg, and the RF model produced the results closest to the observed values, with an ME of 0.002 mg/kg, an MAE of 0.132 mg/kg, and an RMSE of 0.198 mg/kg. The RF model also exhibited the greatest R2 value (0.772). The CART model predictions closely followed, with ME, MAE, RMSE, and R2 values of 0.013 mg/kg, 0.154 mg/kg, 0.230 mg/kg and 0.644, respectively. The three prediction maps generally exhibited similar and realistic spatial patterns of soil Cd contamination. The heavily Cd-affected areas were primarily located in the alluvial valley plain of the Fuchun River and its tributaries because of the dramatic industrialization and urbanization processes that have occurred there. The most important variable for explaining high levels of soil Cd accumulation was the presence of metal smelting industries. The good performance of the RF model was attributable to its ability to handle the non-linear and hierarchical relationships between soil Cd and environmental variables. These results confirm that the RF approach is promising for the prediction and spatial distribution mapping of soil Cd at the regional scale.