Soil Conservation Function Research Articles

Evolution characteristics and meteorological impacts of ecosystem regulation service functions in Jiangxi Province, China from 2000 to 2022.

Jiangxi Province is one of the first ecological civilization demonstration provinces in China. Understan-ding the impacts of meteorological conditions on ecosystem regulatory services is beneficial for conducting ecological protection and restoration work. Based on MODIS data, net primary productivity data, and monthly meteorological data from 2000 to 2022, we used models such as water balance equation and soil loss equation to measure the four regulatory service functions of ecosystem in Jiangxi Province, including carbon sequestration, oxygen release, water conservation and soil conservation. We used trend analysis and partial correlation analysis methods to analyze the spatio-temporal patterns and meteorological influencing factors of those four regulation service functions. The results showed that from 2000 to 2022, the annual average values of carbon sequestration and oxygen release in Jiangxi Province were 178.8 and 130.0 g·m-2, respectively, with annual increases of 0.4 and 0.3 g·m-2. The spatial distribution of both services was consistent, and the average annual carbon sequestration and oxygen release showed an upward trend in 77.3% regions of Jiangxi Province. The average water conservation and soil retention in Jiangxi Province were 591.8 mm and 723.8 t·hm-2, respectively, with similar spatial distributions. The annual increases were 5.6 mm and 3.7 t·hm-2. The soil conservation and water conservation functions of 73.3% and 69.3% regions in Jiangxi Province were steadily improved. Vegetation carbon sequestration and oxygen release was significantly correlated with temperature at monthly scale and seasonal scale. The partial correlation coefficient of those two factors was higher than other factors, which was an important meteorological factor affecting the carbon sequestration and oxygen release function of ecosystem. Precipitation, which was the most important meteorological factor, had a significant positive correlation with water conservation and soil conservation at monthly, seasonal and annual scales. Our results revealed the impacts of climate change on ecosystem regulatory service functions in Jiangxi Province from 2000 to 2022, which could provide scientific and technological support for effectively guaranteeing ecosystem protection and restoration in Jiangxi Province and improving the quality and efficiency of ecological civilization construction.

Assessment of vegetation restoration impacts on soil erosion control services based on a biogeochemical model and RUSLE

Study regionLoess Plateau, China Study focusThe potential soil erosion has commonly been estimated using the revised universal soil loss equation (RUSLE) under bare land conditions. In few studies, biogeochemical models have been employed to simulate natural vegetation dynamics and assess the effects of regional vegetation restoration on soil loss control. In this study, a biogeochemical Biome-BGC (BBGC) model was developed to simulate the potential vegetation dynamics. The soil erosion rate and erosion control indices under both the current land use/cover (A, ERI) and the potential vegetation conditions (A’, ERI’) were estimated using the RUSLE model and an index-based ecosystem service approach, respectively. The effects of vegetation restoration on erosion control services were ultimately evaluated. New hydrologic insights for the regionThe BBGC model performed well in simulating the potential vegetation dynamics. The average annual soil retention increased by 84% after vegetation restoration since 1999. The increased erosion control services accounted for 62% of the Loess Plateau. Erosion control services increased to a high degree (ERI-ERI’ >0.4) in the southeast. Our results demonstrated that vegetation restoration effectively improved the erosion control services on the Loess Plateau. The results could provide a guidance in quantifying the regional effects of vegetation restoration on ecohydrological services and protecting the soil conservation function of watershed ecosystems.

Identifying the effects of landscape pattern on soil conservation services on the Qinghai-Tibet Plateau

Land use patterns affect soil erosion processes and soil conservation services. Identifying key landscape pattern affecting soil conservation services is critical for improving soil conservation services and optimizing land use patterns. In this study, the Qinghai-Tibet Plateau (QTP), where ecosystem services are important, was selected as research area. Based on land use, meteorological, soil and vegetation data, the RUSLE model was used to estimate soil conservation quantitatively from 2000 to 2020. The temporal changes in landscape metrics were analyzed using Fragstats, and the response of soil conservation services to landscape metrics was analyzed by correlation analysis. The landscape pattern showed an obvious temporal change trend. In general, the overall landscape of the QTP became more diversified and fragmented, and the landscape shape tended to become more complicated. Patch density (PD), edge density (ED), landscape shape index (LSI), splitting index (SPLIT), Shannon's diversity index (SHDI), and Shannon's evenness index (SHEI) showed increasing trends, while largest patch index (LPI), mean patch area (AREA_MN), aggregation index (AI), and contagion index (CONTAG) showed decreasing trends. At the class level, the variations of landscape pattern metrics of different land use types were big difference. In the 20-year period, soil conservation services were generally on the rise. The spatial heterogeneity of soil conservation services decreased from the south-east to the north-west. PD and ED were positively correlated with soil conservation function, while AREA_MN and AI had a negative correlation with soil conservation function. The effect of landscape pattern metric variation on soil conservation capacity significantly differed among different land use types. Results of the research offer reasonable evidence for landscape management, water and soil retention function improvement and regional ecological protection on the QTP.

Evaluación de las prácticas de conservación de suelo en la Subcuenca Presa Jalpan, Querétaro, México

This paper's main objective is to evaluate water erosion, and its effect on soil management and conservation practices in the subbasin Jalpan Dam, located at The Sierra Gorda Biosphere Reserve in the State of Queretaro in northern Mexico. This paper was elaborated in four stages: 1) Analysis of soil conservation practices at the study area, with information collected through semi-structured interviews and field verification; 2) Measurement of the effect in soil’s conservation practices on soil’s erodibility, by taking soil samples and in situ measurements on paired plots; 3) Estimation of water erosion and identification of priority areas for its management, by applying the USLE model of Wischmeier and Smith (1978) and the use of GIS (Geographic Information Systems); 4) Estimation of sediment contribution to the Jalpan dam, using the methodology of Aveldaño et al. (1994). As a result, 40 polygons with soil’s conservation practices were located within the Jalpan Dam sub-basin, distributed mainly in the high functional zone. 22 of the 40 polygons were visited, in which 6 types of practices were spotted: reforestations with pine-cedar, maguey lines, agricultural terraces, stone barriers, stone dams and brushwood check dams. The results show deterioration on the structures, more than 30% of them require maintenance and 20% are clogged. Vegetative practices have had little success, reflected in low plant densities and low survival. As a result of the conservation practices evaluations in soil’s erodibility, it was found that in 8 of the 9 sites evaluated, the practices decreased the susceptibility of the soil to erode. It is important to establish systematic supervising mechanisms to ensure proper evaluation of every soil conservation practice condition and function.

Study on the trade-off/synergy between ecosystem services and human well-being based on land use in Weinan City, China.

Change of land use have important impacts on ecosystem services (ESs) and human well-being (HWB), yet the trade-off/synergy among land use, ESs, and HWB has still not received sufficient attention at city regional scales level. Weinan City in the southern of the Loess Plateau of China was taken as the study area. Based on ArcGIS, InVEST model, and RUSLE model, the characteristics of spatial and temporal variations of land use and ESs from 2000 to 2020 were analyzed, and the trade-off/synergy relationship between land use, ESs, and HWB was quantified using correlation analysis. The results indicated that the area of cultivated land decreased significantly and the area of built-up land increased significantly from 2000 to 2020 in Weinan City. The grain production, soil conservation, and water yield functions showed an increasing trend, which was a synergistic relationship with HWB. Carbon storage and habitat quality functions showed a decreasing trend, which was a trade-off relationship with HWB. The index value of HWB has increased significantly, mainly in the added value of agricultural and rural per capita income. Land use intensity has a trade-off relationship with GP, WY functions, and HWB. There are many factors that affect this trade-off/synergy relationship, such as land use patterns, economic development, and population growth. The study can provide a theoretical basis for the sustainable development of regional economy and nature.

Research on Ecological Restoration Evaluation Index System for Construction Projects in Qinghai Tibet Plateau

In the “Ecological Protection Law of the People’s Republic of China on the Qinghai Tibet Plateau” released in April 2023, it is stipulated that “the state strengthens the ecological protection and restoration of the Qinghai Tibet Plateau, adheres to the integrated protection and restoration of mountains, rivers, forests, fields, lakes, grasses, sands, and ice, and implements a systematic governance that focuses on natural restoration and combines natural restoration with artificial restoration.” Currently, there is relatively little research on the ecological restoration evaluation index system in high-altitude areas represented by the Qinghai Tibet Plateau in China. This article studies the climate and soil characteristics of the Qinghai Tibet Plateau region and selects ecological restoration evaluation index systems suitable for high-altitude areas, including biological and community evaluation, soil and water conservation function evaluation, soil and water physical and chemical property evaluation, and landscape pattern evaluation.

Disparities in soil and water conservation functions among different forest types and implications for afforestation on the Loess Plateau

Afforestation is widely acknowledged as an effective approach for enhancing ecological conditions. Considering the challenging ecological environment on the Loess Plateau, prioritizing soil and water conservation functions in stands is crucial. The study aimed to ascertain the future development direction of forestry on the Loess Plateau by examining two representative forest types: planted forest (Robinia pseudoacacia pure forest and Pinus tabulaeformis pure forest), and natural secondary forest (a mixed forest of Quercus liaotungensis and Populus davidiana). The assessment centered on the soil and water conservation functions of the two forest types, encompassing the water conservation function (rainfall distribution and changes in multi-year soil moisture storage (0–200 cm)), soil conservation function (soil physicochemical properties), and understory plant diversity and stability. The results indicated that natural secondary forests outperformed planted forests in terms of water conservation function by effectively converting more precipitation into soil moisture, reducing runoff, and maintaining higher soil moisture storage. Additionally, natural secondary forests exhibited superior soil conservation functions compared to planted forests, characterized by higher soil porosity and nutrient properties. The variation in community structure between the shrub and herbaceous layers was more significant among different forests than within each forest (P < 0.05). Natural secondary forests exhibited higher understory shrub and herb biodiversity and interspecific repeatability compared to planted forests. Therefore, natural secondary forests are a more suitable forest type considering the natural conditions and silvicultural objectives of the Loess Plateau. To enhance the quality of afforestation, it is recommended to adopt near-natural planting patterns that replicate the environmental conditions of natural forests. For instance, actively creating mixed forests that emulate the tree species composition of natural forests and gradually reducing dependence on a single dominant tree species. Furthermore, the arborous and litter layers had a more direct and substantial influence on soil and water conservation functions compared to the shrub and herb layers. Foresters should prioritize regulating stand structure, such as increasing canopy variability, to enhance the water conservation function of stands. Additionally, they should actively protect the understory litter to fulfill its role in enhancing soil quality. This study provides a theoretical foundation and practical guidance for the implementation of vegetation restoration in ecologically vulnerable areas, such as the Loess Plateau.

Multifunctional trade-off and compensation mechanism of arable land under the background of rural revitalization: a case study in the West Mountain Regions of Hubei Province.

Exploring the spatial relationship and ecological compensation mechanism of each function of arable land in poor mountainous areas is important to promote rural revitalization and enhance arable land protection. Taking the mountainous region of Western Hubei (MRWH) as an example, this study quantified the "three living" functions of arable land and its secondary functions. Using the root mean square deviation method to calculate the trade-off index, a quantitative method can more scientifically reflect the trade-off relationship between arable land functions and measure the overall ecological compensation. Studies have shown that (1) the value of the production function exhibits a growing and subsequently a falling trend, whereas the value of living function and ecological function exhibits an increasing trend over time, with an average functional value of 5310, 220 and 6496 million yuan, respectively. The spatial pattern of the "three living" functional values decreases from west to east. Among them, water conservation and soil conservation function values show a high distribution in the south and low in the north, gas purification and agricultural pollution functional values show a scattered spatial pattern, and the value of other functions shows an increasing trend from southeast to northwest; (2) among the primary functions, the trade-off between production and ecological functions is the strongest, decreasing, and then increasing over time, with an average trade-off index of 0.89. Among the secondary functions, there is the most obvious trade-off between the food supply function and the five ecological functions, which requires coordination; (3) overall, the total amount of ecological compensation has shown an upward trend, with priority areas for level I ecological compensation increasing year by year. Optimized compensation zones and potential compensation zones are concentrated in the northwest, ecological balance zones are located in the central part, and optimized development compensation zones and key development compensation zones are located in the southeast. According to the research, MRWH is oriented to ecological function, followed by the production function, supplemented by the living function. Green agriculture should be vigorously developed and ecological function space should be compressed by strictly limiting the excessive expansion of production activities. Promoting the improvement ofproduction function through ecological function, while exploring the potential value of living function. Ecological compensation in strict accordance with the priority of ecological compensation, zoning. Realizing cross-regional cooperation, low compensation areas drive high compensation areas to achieve sustainable development of arable land.

Optimization of China's ecological tax system based on GEP development strategy

To reduce ecological environmental pollution and economic loss, and improve national environmental awareness, this paper puts forward the optimization of China's ecological tax system based on the GEP development strategy. Firstly, the analysis shows that GDP focuses on economic operation, while GEP focuses on ecosystem operation. Then, GEP is used to calculate the data of water conservation, soil conservation function, flood regulation and storage, air and water purification, carbon fixation and oxygen release, climate regulation, biological community, and other indicators to obtain the corresponding value. We will use fiscal principles to adjust the sensitivity of economic changes, the principle of fairness to narrow income disparities, and the principle of efficiency to adjust market collection and management, simplify the tax system, and improve national treatment. Finally, the maximization of tax benefits is realized with the minimum tax cost under the tax system. Through experiments, it is proved that this method can effectively explore the development of an ecological tax system, to optimize the overall optimization of tax collection and management up to 0.77.

Pursue the coordinated development of port-city economic construction and ecological environment: A case of the eight major ports in China

As the node of traffic and the center of regional social and economic development, port cities have the dual attributes of ports and cities. To analyze the sustainable development condition of port cities, this paper selected eight representative ports located in the Yangtze River Delta, Pearl River Delta and Bohai Rim in China, considered the geographical distance, measured the accessibility between ports and hinterland cities through an improved gravity model. Using the In-VEST model, the ecological service levels of port cities were evaluated based on four indicators: water supply, climate regulation, biodiversity, and soil conservation, then conducted a comprehensive study on the interrelationship between port-hinterland accessibility and ecological service level. The results showed that the port-hinterland accessibility index was consistent with port influence and urban economic strength. The ecological service levels of the eight port hinterland cities were significantly different, and the four ecological functions showed a synergistic relationship. However, most hinterland cities had relatively poor soil conservation functions and low coordination of ecological service indicators. Among the eight regions, only Ningbo, Zhoushan and Shenzhen had a highly sustainable development capacity, while the remaining six regions failed to achieve the synergistic development of economic construction and ecological environment. Port production level, city economic strength and ecological service level jointly influence the development of the port city system. While improving the accessibility of port cities, it is necessary to focus on the protection of the ecological environment in order to enhance sustainable development.

PERSEPSI MASYARAKAT TERHADAP PENGELOLAAN AGROSILVOPASTURA DI HUTAN RAKYAT DESA KARYASARI

Forest management by the people independently has been promoted by the government since the 1980s. As a result, people are now starting to understand the importance of forest management on privately owned land. The function of private forests, apart from increasing people's income, is also for soil and water conservation. The impact of the function of soil and water conservation is widely felt by the community, not only by land owners. The community's sustainable forest management model is managed by combining timber plants with agricultural crops, to obtain benefits more quickly. This method is better known as agroforestry. Agroforestry management develops by combining three commodities, namely timber, agricultural crops and livestock crops, which is called agrosilvopastura. The management of agrosilvopastura is still not widely known by the community, therefore in this stud, we want to know the level of public understanding or perception of the community about the management of agorsilvopastura. The research was conducted in Karyasari Village, Leuwiliang District, Bogor Regency. It was carried out in Leuwiliang District because the potential for community forest is quite large for the Bogor Regency area. Methods of data collection by distributing closed questionnaires and processing with a Likert scale. The results of this study indicate that the people of Karyasari Village have a good perception of 4.328 on the Likert scale. This shows that the people of Karyasari Village have a good understanding of the implementation of agrosilvopastura. Agrosilvopastura activities in Karyasari Village have been well integrated so that they can provide a high contribution to community income, namely 53% from the forestry sector, 24.8% from the agricultural sector and 9.1% from the livestock sector.

Analysis of trade-offs/synergies in land use function changes in Bin County, China

Land use function has become an important part in land change science. More attention should be given to multifunctional land to achieve land structure optimization and sustainable land use. This study takes Bin County in Heilongjiang province of China as the research area and investigates the spatiotemporal pattern and trade-off synergistic relationship of land functions from 2000 to 2020. Land functions were quantitatively measured by the spatiotemporal method of statistical data, INVEST model, CASA, RUSLE, and other models. The results showed that 1) during 2000–2020, the production function showed an overall trend of enhancement. Living function remained enhanced except in the southeast and north. The water conservation function was weakened in most areas, while the carbon fixation function was strengthened in the southeast and weakened in the central and northern parts. Soil conservation function decreased first and then increased significantly in the southwest. 2) There was a synergistic relationship between production and living functions and trade-off relationships between ecology and production functions and ecology and living functions from 2000 to 2020. 3) The production and living functions are mainly coordinated in space, and the collaborative agglomeration types are mainly distributed in Tangfang town, Manjing town, and other areas. The spatial distribution of trade-offs and synergies between ecological and productive functions and ecological and living functions was similar. The trade-off and agglomeration types were scattered, and the synergies were distributed in Binxi town and Juren town.

Impact of Land Use Change on the Spatial and Temporal Evolution of Ecosystem Service Values in South China Karst Areas

Resource depletion, land-use change, and population growth triggered by the industrial revolution represent serious issues shared globally that have altered the structure, processes, and functions of ecosystems and had significant impacts on human well-being and survival security. This paper assesses changes in ecosystem service values (ESVs) in karst areas based on the perspective of land-use change. Guizhou province, which is typical of the South China Karst (SCK) ecologically fragile areas, was taken as a research subject. The past, current, and future spatial-temporal evolution of karst ESVs were assessed, using equivalence factors and CA-Markov modelling methods. The results show that: (1) from 1980 to 2040, arable land, woodland, and grassland occupy the main land types in the study area; at the same time, the water and built-up areas show a steady growth trend, with dramatic land use shifts occurring in the western, middle, and northern parts. (2) The overall ESVs increased by US$ 31.12 million during the study period, showing a temporal change trend of first decreasing and then increasing; forest land, grassland, and arable land area shift are the main factors of ESVs change; soil conservation, biodiversity conservation, and gas regulation functions are enhanced and play a vital role in the single ESVs increase; ESVs show a basin-type spatial distribution pattern. (3) The sensitivity index is &lt;1, the ESV is inelastic to the VC factor adjustment, and the results are true and valid. This paper found that using quantitative methods to predict land use change of the South China Karst can provide accurate assessment of the differences in supply and demand for natural and social ecosystem services (ES) in a region, clarifying the trade-offs and synergies of ecosystem service functions, contributing to the achievement of sustainable development, and providing a practical reference for global land landscape optimization and land resource planners.

Analysis of Eco-Environmental Geological Problems and Their Driving Forces in the Henan Section of the Yellow River Basin, China

(1) Background: The Henan section of the Yellow River Basin plays an important role in the economic zone of the middle reaches of the Yellow River. However, ecological environmental geological problems such as soil erosion have seriously affected the lives of residents and economic development, resulting in increasingly prominent conflicts between humans and the environment. Therefore, this paper made use of remote sensing images and other reference data, integrated image classification, remote sensing inversion and statistical analysis methods to explore the ecological environmental geological problems and their causes in the Henan section of the Yellow River Basin. (2) Results: the main eco-environmental geological problems in the Sanmenxia–Zhengzhou section are serious soil erosion, degradation of water conservation function and being prone to geological disasters. The main eco-environmental geological problems in the Zhengzhou–Puyang section are poor water and soil conservation function, degradation of water conservation function and poor biodiversity maintenance function. In the last 19 years, the eco-environmental geological problems in the Henan section of the Yellow River Basin have shown a significant improvement trend as a whole. Along the main stream of the Yellow River in Sanmenxia, Luoyang, Jiyuan, Jiaozuo, Zhengzhou and other areas, the eco-environmental geological problems are still prominent; altitude, vegetation and rainfall are the key driving factors of eco-environmental geological problems in the Sanmenxia–Zhengzhou section and rainfall, vegetation and land-use type are the key driving factors in the Zhengzhou–Puyang section. (3) Conclusions: This study comprehensively considered the three aspects of ecology, environment and geology in a total of five research topics. The temporal and spatial distribution characteristics and driving factors of ecological environmental geological problems in the Yellow River Basin were analyzed, which could provide technical support for ecological environmental protection and high-quality development in the Yellow River Basin.

Evaluation of the Protection Effectiveness of Natural Protected Areas on the Qinghai-Tibet Plateau Based on Ecosystem Services.

Evaluating the protection effectiveness of natural protected areas is an important step in successful management. Adopting 330 natural protected areas on the Qinghai-Tibet Plateau as research subjects, the regional dominant ecosystem service function was selected, and various temporal and spatial analysis methods were employed to analyze the evolution characteristics and influencing factors of ecosystem service patterns from 2000 to 2020. Our results indicated that (1) the water conservation function stabilized after fluctuation and decline, the soil conservation function fluctuated upward, and the windbreak and sand fixation function exhibited an increase after a decreasing fluctuation. (2) The protection effectiveness of25 protected areas significantly improved, that of 151 protected areas improved, that of 84 protected areas stabilized, that of 56 protected areas worsened, and that of 14 protected areas significantly worsened. (3) The top three influencing factors in descending order were precipitation change > altitude > mining area density. (4) Remarkable protection results were achieved in national protected areas, established management institutions, earlier established areas (before 2000), and areas exhibiting alow built-up area density (<0.75%) and low mining density (<1%). Our study provides technical support for the construction and management of protected areas and improvement in ecosystem service functions on the Qinghai-Tibet Plateau.

Response of Erosive Precipitation to Vegetation Restoration and Its Effect on Soil and Water Conservation Over China's Loess Plateau

AbstractLarge‐scale vegetation restoration profoundly affects ecohydrological and hydrometeorological processes with consequent effects on soil and water conservation. However, it is still unclear how revegetation affects the joint relationship between streamflow and sediment yield from the land‐atmosphere interactions perspective. In this study, we combine in situ hydro‐meteorological observations, satellite observed land surface characteristics, and coupled land‐atmosphere model simulations to address this knowledge gap through a case study focusing on the Loess Plateau, where a megaproject of revegetation has been implemented since 2000. We find that historical annual streamflow and sediment yield have decreased over the Loess Plateau and 12 main revegetated basins, mainly due to enhanced canopy transpiration and soil conservation functions of revegetation. However, the magnitude of sediment yield reduction is much higher than that of streamflow for both mainstream and tributaries of the Yellow River. Specifically, the mean decreasing rate of sediment yield is 2.91 times of streamflow in the mainstream Yellow River, while for tributaries, the mean decline rate of sediment yield is 1.71 times of streamflow. Despite increases in total precipitation amount, erosive precipitation exhibits a clear downward trend over the Loess Plateau after the large‐scale revegetation (2000–2015). This is mainly driven by enhanced local moisture recycling caused by revegetation‐induced redistribution of water and energy budgets. Decreases in erosive precipitation frequency coupled with increased precipitation amount enhance streamflow availability and simultaneously mitigate soil erosion. Our findings highlight the importance of factoring in the two‐way feedbacks between revegetation and erosive precipitation when planning soil and water conservation.

Study on Chinese Farmland Ecosystem Service Value Transfer Based on Meta Analysis.

An analytic database was built based on meta-regression analysis (MRA) method, mainly including ecosystem service type, farmland division, cultivated land type, value assessment method, and farmland characteristics. The feasible weighted least square (FWLS) method was adopted to comprehensively investigate the seventy observations from empirical studies. The results indicate that: (1) except the negative impact of farmland area on farmland value, such factors as paddy field, good soil conservation function, mainly providing agricultural products, and using market value method for assessment all produce positive effect on the promotion of farmland value. (2) In meta-regression analysis, the average transfer error is 36.74%, and the median transfer error is 14.59%. (3) Under the A1B, A2, B1, and B2 scenarios of IPCC SRES, it is discovered from calculation that the value changes under different scenarios have some differences, in which, the total value rises significantly under A2 scenario and will reach to 15,220 billion yuan until the year of 2100; while the total value loss is the greatest under B1 scenario and will fall to 6320 billion yuan until the year of 2100. Finally, this paper gives some suggestions for scholars to deeply study the service value of farmland ecosystem as well as for the government to formulate differentiation policies.

Study on the relationship between topological characteristics of ecological spatial network and soil conservation function in southeastern Tibet, China

Many regions on the globe are at risk of soil erosion, especially in the ecologically fragile areas of the Qinghai-Tibet Plateau. Enhancing the soil conservation capacity of regional vegetation is one of the main ways to address soil erosion. However, most studies ignore the relationship between the spatial distribution structure of vegetation and soil conservation capacity, and the construction of ecological spatial networks is an effective means to study the spatial distribution structure of vegetation. In this study, we extracted the ecological spatial network of Southeast Tibet by the minimum resistance model (MCR) and combined the ecological network with complex network theory to calculate the topological indices of the ecological spatial network and ecological nodes. Subsequently, the soil conservation capacity of ecological nodes is calculated based on the USLE model, and the relationship between it and topological indices is analyzed. It was shown that the degree, closeness centrality, betweenness centrality and eigenvector centrality of forest nodes showed a positive linear correlation with their soil conservation capacity, and the clustering coefficient of grassland nodes showed a positive linear correlation with their soil conservation capacity. This study calculates habitat quality based on the Invest model. We propose a Integrated Soil Conservation and Habitat Quality Evaluation (ISHE) Model to determine the direction of network optimization and propose an optimization strategy. We analyze the network robustness and soil conservation capacity and find that the optimized network robustness and soil conservation capacity are significantly improved. This study provides strategies and methods to protect ecologically vulnerable areas, optimize the spatial distribution of vegetation, and enhance soil conservation capacity. In addition, this can provide a theoretical reference for planning national ecological projects. We use the ISHE model to filter out three types of nodes that need to be focused on optimization and propose different optimization strategies.

Evaluation of soil and water conservation function in the Wugong mountain meadow based on the comprehensive index method

Wugong Mountain meadow landscape is well-known both at home and abroad because of its ornamental value. Our study aimed to comprehensively evaluate the function of soil and water conservation at different altitudes of Wugong Mountain meadow soil. The hydro-physical characteristics, including the soil bulk density, porosity, water content, water holding capacity, and permeability of meadow soil at 1600 m–1900 m altitudes, were analyzed. The results showed that the mountain meadow soil's hydro-physiological characteristics and water conservation function significantly differed with altitude. However, the trend of each index did not follow the same law with altitude change. There was a decrease in bulk density of the soil from 1700 m to 1900 m, but a significant increase in porosity and water-holding capacity. Despite the higher porosity and water holding capacity found at 1600 m than at 1700 m and 1800 m, a similar bulk density was found at 1600 m as 1700 m. In addition, the bulk density in the 0–20 cm layer was lower than that in the 20–40 cm layer, while the porosity and water-holding capacity were higher. A higher sequence of soil water conservation capacity was found in soil layers 0–20 cm depth at 1900, 1600, 1800, and 1700 m; in soil layers 20–40 cm depth, it was at 1900, 1800, 1700, and 1600 m. The study found that the sequence of the comprehensive performance of soil water conservation function was at 1900, 1600, 1800, and 1700 m altitudes in the Wugong mountain meadow area. Our comprehensive study of soil water conservation capacity provides a theoretical basis for the rational use of mountain meadow resources in subtropical regions.

Quantitative assessment of biocrust distribution patterns using landscape indices benefits the study of their soil conservation functions

Biological soil crusts (biocrusts) are widely distributed covers and show obvious differences in coverage, composition, and distribution patterns under field conditions. To date, it is still difficult to assess the ecological function of biocrusts in different distribution patterns due to challenges in quantitatively assessing their patterns. Landscape ecology inspired us to characterize and describe landscape distribution patterns through a series of indices. Accordingly, this study developed a method to quantitatively characterize the distribution pattern of biocrusts at the plot scale. Our results demonstrated that optimum grain size selection is important. The first inflection point determines the optimum grain size of 5 mm. Based on this grain size, four landscape indices were selected out of fifteen, including the percentage of the landscape (PLAND), edge density (ED), patch cohesion index (COHESION), and splitting index (SPLIT), which represented 91.6 % of the total distribution characteristic information of biocrusts within 58 squares of 1.5 × 1.5 m. The four landscape indices were validated for applicability by describing biocrust characteristics for various patterns, scales, and coverage levels both in the laboratory and field plots. This method for quantitatively assessing the distribution characteristics of biocrusts lays a foundation for the study of the relationship between the distribution pattern of biocrusts and ecological functions and processes.