Terrain Gradient Research Articles

柑橘园扩张对生态系统服务和景观格局的影响——以江西省信丰县为例

PDF HTML阅读 XML下载 导出引用 引用提醒 柑橘园扩张对生态系统服务和景观格局的影响——以江西省信丰县为例 DOI: 10.5846/stxb202108152249 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（71873053）；国家社会科学基金重大项目（18ZDA054） Effects of citrus orchard expansion on ecosystem services and landscape pattern: A case study of Xinfeng County, Jiangxi Province, China Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:柑橘园扩张是我国柑橘主产区较典型的土地利用/覆盖变化过程之一。但柑橘园扩张对区域生态系统服务和景观格局的影响尚不清楚，探明柑橘园种植的生态效应对柑橘主产区实现生态-经济协同发展具有重要的理论和现实意义。以江西省信丰县为研究区，基于第二次、第三次全国国土调查数据，借助InVEST模型、景观格局指数、图谱分析等方法，结合地形梯度和相关性分析，对柑橘园扩张所致的生态系统服务和景观格局变化及其权衡与关联进行分析。结果表明：①2010-2019年，柑橘园扩张方向以占用林地和耕地为主，柑橘园面积从9961.29 hm2增至12633.84 hm2，其中新增柑橘园7504.72 hm2，退出柑橘园4832.16 hm2，区域内柑橘园转换频繁。②柑橘园扩张导致信丰县景观格局总体呈现破碎化趋势，景观连通性降低，并对土壤保持服务和碳储量服务产生负向影响，对柑橘供给服务产生正向影响，对产水服务几乎无影响。③不同类型柑橘园在不同地形梯度上的扩张对生态系统服务的影响方向和程度存在差异。④在权衡与协同分析中，供给服务与支持服务呈权衡关系，碳储量-产水、碳储量-土壤保持等支持服务之间呈协同关系；景观破碎化与生态系统服务显著关联。研究结果可为经济作物大规模种植区的园地合理开发利用和生境保护提供科学依据。 Abstract:The conversion of natural forest and cultivated land to citrus orchard has become one of the typical land use/cover change processes in major citrus producing areas in China. Enlarging citrus cultivation can bring promising profitability to smallholders. However, the ecological consequences of enlarging citrus cultivation on ecosystem services (ES) and landscape patterns remain unclear. It is of great significance to explore the ecological effects of citrus orchard scale planting on the eco-economic synergistic development of major citrus producing areas. This paper focuses on analyzing the changes of ESs and landscape pattern, their correlation and the tradeoff/synergy of ESs change caused by citrus orchard expansion, using a case of Xinfeng County, Jiangxi Province. First, we used TUPU analysis methods to characterize the spatial and temporal variation of citrus orchard expansion from 2010 to 2019, based on the data of the secondly and thirdly national land survey. Second, InVEST model was employed to evaluate critical ES dynamics caused by citrus orchard expansion, and then we analyzed its differences in different terrain gradients. Third, we applied correlation analysis to examine the tradeoffs between ESs and the relationships between ESs and landscape patterns. The results showed that:(1) from 2010 to 2019, the expansion direction of citrus orchards was mainly converted from forest land and cultivated land, and the area of citrus orchards increased from 9961.29 hm2 to 12633.84 hm2, with 7504.72 hm2 newly transferred in and 4832.16 hm2 transferred out. The contradiction among forest land, cultivated land and citrus orchard is prominent in Xinfeng County. (2) The expansion of citrus orchards has boosted the supply of citrus supply services, whereas it had a negative impact on soil conservation services and carbon storage services. Soil conservation and carbon storage services decreased by 67.19% and 35.98%, respectively, from 2010 to 2019 throughout the region as a whole. Surprisingly, its impact on water yield services was not significant, with only a 5% reduction over the research period. Moreover, citrus orchard expansion has also resulted in a decrease in landscape connectivity and a trend of fragmentation in Xinfeng County. (3) The expansion of different citrus orchards on different terrain gradients had different effects on ESs. (4) In the tradeoff and synergy analysis, there was a tradeoff relationship between supply services and support services, and there was a synergy relationship between carbon storage-water yield and carbon storage-soil conservation. It is found that landscape fragmentation is significantly correlated with ESs. These results can provide scientific evidence for the rational development and utilization of gardens and habitat protection in large-scale cash crop planting areas. 参考文献 相似文献 引证文献

Spatiotemporal differentiation of village ecosystem service bundles in the loess hilly and gully region and terrain gradient analysis

Spatiotemporal differentiation of village ecosystem service bundles in the loess hilly and gully region and terrain gradient analysis

Airborne Acoustic Transmission and Terrain Topography at SAINTGITS Amphitheatre: An Analysis of Outdoor Auditory Perception and Comparison of Contour Plots

The arrangement of natural and physical features on the earth’s surface are a few among the countless items that govern the airborne acoustic transmission at boundary layers. In particular, if the acoustic waves are attributes of live concerts at open-air theatres, without losing the sheen and quality, the audience should certainly receive the unbroken depth of the performance. Hence, at all times, it is advisable to analyse the auditory receptiveness, particularly in all intended recreational spaces. The current pandemic circumstances and the mandated COVID-19 prevention protocols encourage gatherings in naturally ventilated outdoor regions than confined indoors. This work predicts and quantifies the acoustic experience at the naturally carved amphitheatre at SAINTGITS, an autonomous institution at the down South-West of the Indian Subcontinent. The entire recreational space at SAINTGITS AMPHI was separately modelled as a Base case and Advanced case, and were analysed using the acoustic modelling module of EASE Focus, a renowned simulation freeware, which is in strict adherence with the International standards. The variation in loudness received at the nearest and farthest ends of the amphitheatre was between 67 to 80 dB. Though the Zero frequency SPL (Z-weighting) exhibited the loudness in the range of 81 to 85 dB and could maintain a safer auditory level for any human ear, it was confined to a hemispherical region near the sound source. A vertical beam angle of −4.0° was found to be effective throughout. The procedures and analyses will certainly help the future organizers and stakeholders to effectively plan the resources to reap rich acoustic experience at terrain-centric locales. The surface topography and contours were plotted with another set of freeware, the CADMAPPER and the QUIKGRID, to compare terrain gradient with the known data. Furthermore, this interdisciplinary research exhibits the extensive simulation capability of both EASE Focus and QUIKGRID and demonstrates the modelling versatility and deliverable potential of these freeware to benefit the budding architects and researchers.

Coupling responses of landscape pattern to human activity and their drivers in the hinterland of Three Gorges Reservoir Area

Human activities and landscape patterns are important representations of two major elements in the human-land system. Therefore, analyzing coupling characteristics of human activity intensity and landscape patterns is of great significance to reveal the evolution of regional human-land relationships. To fill the hole on the coupling response of human activity intensity and landscape pattern, the mountainous human activity intensity and landscape pattern coupling model was constructed, and the comprehensive dominant-recessive human activity intensity index (CHAI) was proposed. Moreover, based on the AHP and cumulative index method, we quantitatively evaluated the human activities intensity of Fengjie County in the hinterland of Three Gorges Reservoir Area (TGRA) from 2000–2020, and analyzed spatial coupling patterns between CHAI and landscape pattern through the local spatial autocorrelation model. Finally, factors influencing the type of coupled change in CHAI and landscape pattern were explored by a binary logistic regression model. The results show: (1) There are no obvious changes in CHAI of Fengjie County, but the spatial change shows the characteristics closely related to the terrain gradient and the level of economic development of Fengjie County with an overall contraction while local enhancement. (2) The spatial coupling between CHAI and landscape pattern in Fengjie County shows four types: Coordination type, antagonism type, gradually coordinated type, gradually antagonistic type. (3) The important impact factors of the coupling between CHAI and landscape pattern are distance to county administrative center, distance to the town government, and landform, etc., which reflects socio-economic factors were the main factors in the evolution of the regional social ecosystem. (4) There are diverse and special coupling responses between human activity intensity and landscape patterns in the hinterland of TGRA. In general, the hinterland of TGRA has achieved a win-win situation for the ecology and economy through partial disharmony in exchange for overall coordination. Moreover, the research results reveal the uniqueness of China's mountainous landscape pattern in response to human activities in recent years.

Flood Hazard Modelling in Upper Mandakini Basin of Uttarakhand

Floods in Himalayan region raise serious concerns regarding ongoing path of development as recent manifestations of catastrophic events establish link between climate changes and risk to anthropogenic activities in mountainous regions. Scientists predict frequent occurrence of such disasters wherein rapid glacial melting; incidents of glacial lake outburst and weather extremes may trigger floods in the Himalayan mountains. This paper examined flood risk in Upper Mandakini basin through GIS based flood simulationto highlight flood potential and risk associated with such hazard in the study area.It is observed that floods in study area display hazardous interplay of natural terrain gradient, high kinetic energy of streams, and intense rainfall. The upper sections of basin that includes Kali Ganga, Mandani Ganga, Madhyamaheshwar and Mandakini rivers shows high flood susceptibility with greatest risk in the latter. Such hazardousness is likely to be intensified by ongoing anthropogenic activities in the basin.

Spatial Variation and Terrain Gradient Effect of Ecosystem Services in Heihe River Basin over the Past 20 Years

With the advent of large-scale development, extreme imbalance in the ecology of the Heihe River Basin (HRB) has caused a series of ecological problems. In order to explore the spatiotemporal variation of ecosystem services (ESs) and to assess the characteristics of ESs under the terrain gradient effect (TGE), the three key ESs were quantified based on the InVEST model using five series of land-use data obtained from remote sensing images from 2000 to 2020 in this study. The terrain index was used to analyze the influence of terrain on ESs. The results show that most of the ESs were in high numbers in the south and low numbers in the north, as well as high numbers in the middle and upper reaches and low numbers at downstream locations. It was found that high-quality habitats degrade to general-quality habitats, and poor-quality habitats evolve into general-quality habitats. It was also found that the water production volume continues to decline and soil conservation becomes relatively stable with little change. This study illustrates different ESs showing obvious TGE with changes in elevation and slope. These results indicate that the effect of land-use change is remarkable and TGE is highly important to ESs in inland watersheds. This research study can provide a scientific basis for the optimization of regional ecosystem patterns. The results are of great significance in terms of rational planning land use, constructing ecological civilizations, and maintaining the physical conditions of land cover at inland river basins.

Identification of the trade-offs/synergies between rural landscape services in a spatially explicit way for sustainable rural development

Rural problems are becoming increasingly prominent in sustainable development in China. Landscape services (LSs) are an emerging concept associated with ecosystem services and play an important role in promoting sustainable development. However, a comprehensive framework of rural LS and empirical research are still lacking. Here, we proposed a rural LSs system based on its multiple functions of “ecological maintenance, agricultural production and human living”, including 9 LS types. Combined with the impact of landscape pattern on LSs, we optimized the assessment method of LS, and the LS capabilities were assessed at the village scale in Hangzhou city. Furthermore, we identified the spatial differentiation of rural LSs capabilities and trade-offs/synergies along urban-rural and terrain gradients. The results showed that the LSs capabilities of the rural landscape were greatly affected by the urban radiation and terrain, and we found that the turning point of LSs capabilities was 35 km from the urban fringe and the terrain gradient T5. The LSs in most villages (77%) revealed trade-offs, and the villages with LS synergies largely occurred in the middle and eastern regions of the study area. This study could improve our current understanding of LSs in regard to sustainable rural development, and identifying the trade-offs/synergies of LSs in a spatially explicit way can provide suggestions for the differentiated management of rural landscape sustainability.

Evolution of Habitat Quality and Its Topographic Gradient Effect in Northwest Hubei Province from 2000 to 2020 Based on the InVEST Model

Regional land use change and ecological security are important fields and have been popular issues in global change research in recent years. Regional habitat quality is also an important embodiment of the service function and health of ecosystems. Taking Shiyan City of Hubei Province as an example, the spatiotemporal differences in habitat quality in Shiyan City were evaluated using the habitat quality module of the InVEST model and GIS spatial analysis method based on DEM and land use data from 2000, 2005, 2010, 2015, and 2020. According to the habitat quality index values, the habitats were divided into four levels indicating habitat quality: I (very bad), II (bad), III (good), and IV (excellent), and the topographic gradient effect of habitat quality was studied using the topographic position index. The results show the following. (1) The habitat quality of Shiyan City showed relatively high and obvious spatial heterogeneity overall and, more specifically, was high in the northwest and southwest, moderate in the center, and low in the northeast. The higher quality habitats (levels III, IV) were mainly distributed in mountain and hill areas and water areas, while those with lower quality habitats (levels I, II) were mainly distributed in agricultural urban areas. (2) From 2000 to 2020, the overall average habitat quality of Shiyan City first increased, then decreased, and then increased again. Additionally, the habitat area increased with an improvement in the level. There was a trend in habitat transformation moving from low to high quality level, showing a spatial pattern of “rising in the southwest and falling in the northeast”. (3) The habitat quality in the water area and woodland area was the highest, followed by grassland, and that of cultivated land was the lowest. From 2000 to 2020, the habitat quality of cultivated land, woodland, and grassland decreased slightly, while the habitat quality of water increased significantly. (4) The higher the level of the topographic position index, the smaller the change range of land use types with time. The terrain gradient effect of habitat quality was significant. With the increase in terrain level, the average habitat quality correspondingly improved, but the increasing range became smaller and smaller. These results are helpful in revealing the spatiotemporal evolution of habitat quality caused by land use changes in Shiyan City and can provide a scientific basis for the optimization of regional ecosystem patterns and land use planning and management, and they are of great significance for planning the rational and sustainable use of land resources and the construction of an ecological civilization.

Landscape ecological risk assessment of farming-pastoral ecotone in China based on terrain gradients

Farming-pastoral Ecotones in China (FPEC) is one of the most fragile ecological area in China. Landscape ecological risk assessment of FPEC based on terrain gradients has important strategic significance for ensuring national ecological security and the sustainable development of social economy. Based on the 30 × 30 m land use data and DEM data of FPEC in 1980, 1990, 2000, 2010 and 2020, this paper constructs a landscape ecological risk assessment model, and uses the methods of spatial autocorrelation analysis and terrain distribution index to appraise the dynamic change law and influential factors of FPEC landscape ecological risk on various terrain gradients. The results showed that: (1) In recent 40 years, land use/land cover changes (LUCC) has significantly changed, and the farmland area has increased continuously, mainly transferred from grassland, forest and bare land, particularly the bare land converted into grassland in recent 10 years, which leads to substantial increase in grassland area. (2) The overall ecological risk of the study area showed an upward trend, and the area of highest risk regions has increased more than twice during the study period, mainly distributed in the regions of "interference of human activities in low terrain" and "change of natural high terrain environment," these regions showed a high spatial concentration. (3) Ecological risk along with terrain gradient distribution is mainly limited by climate and terrain factors, the interference of human activities and natural environment change are the main influential factors of ecological risk increase in low and high terrain, respectively. Therefore, it is necessary to adapt to local conditions, and low terrain should rationally develop and utilize natural resources to reduce the interference of unreasonable production and human activities. In order to promote the sustainable and healthy development of FPEC, the policy of closing hillsides to facilitate afforestation should be adopted in the high terrain to reduce the impact of natural environment changes.

Spatial and temporal variations of vegetation coverage in the middle section of Yellow River Basin based on terrain gradient:Taking Yan'an City as an example.

Vegetation restoration is an important requirement for ecological protection and high-quality development in the Yellow River Basin. In-depth understanding the temporal and spatial differentiation of vegetation has important practical significance. With the four Landsat TM/OLI remote sensing images as the data source, the pixel binary model was used to estimate vegetation coverage. The transfer matrix, geological information map, and the center of gravity migration model were used to analyze the temporal and spatial variations of vegetation coverage in Yan'an City in the middle of the Yellow River Basin from 1988 to 2018. The spatial variation of vegetation cover to elevation and slope was explored using terrain distribution index combined with terrain data. The results showed that vegetation coverage in Yan'an was low in the north region and high in the south region. The vegetation coverage increased significantly due to policy changes. From 1988 to 2018, the vegetation change pattern in Yan'an was dominated by continuous improvement and stability. Vegetation coverage increased in about 50% of the area. 83% of the study area with high vegetation coverage remained stable. At each elevation and slope level, the advantage of high vegetation cove-rage increased with time. At each slope level, vegetation cover increased with slope. The transition direction of vegetation cover of different levels in Yan'an was basically consistent with the overall spatial change trend of vegetation cover, with the overall shift being from north to west. The vegetation construction in Yan'an has achieved remarkable results, though the vegetation coverage in the north still needs to be improved. Optimizing vegetation types and structures is an important direction for future vegetation construction.

How to visualize the Urban Heat Island in Gridded Datasets?

Abstract. The Urban Heat Island (UHI) describes the increase of near surface temperatures within an urban area compared to its rural surrounding. While the concept of the UHI is in itself quite simple, it is more complex to apply it to gridded datasets. The main complication lies in the rural baseline definition. Therefore, we propose three approaches to calculate the spatial UHI representation for gridded datasets from (i) a single point baseline, (ii) an area averaged baseline, and (iii) a nearest neighbor-based baseline field. Based on these approaches, seven methods are tested as an example for a case study utilizing model simulations for three metropolitan areas in Central and Western Europe (Berlin, Paris and Rhine-Ruhr Metropolitan Area). The results show that all methods perform reasonable in absence of complex terrain, biases and large scale temperature gradients. However, with at least one of these features present, the UHI visualization is less prominent or nonexistent, except for the nearest-neighbor approach which consistently shows reasonable spatial characteristics of the UHI across all scenarios.

Spatiotemporal Variation in Ecosystem Services and Their Drivers among Different Landscape Heterogeneity Units and Terrain Gradients in the Southern Hill and Mountain Belt, China

Understanding the spatiotemporal heterogeneity of ecosystem services (ESs) and their drivers in mountainous areas is important for sustainable ecosystem management. However, the effective construction of landscape heterogeneous units (LHUs) to reflect the spatial characteristics of ESs remains to be studied. The southern hill and mountain belt (SHMB) is a typical mountainous region in China, with undulating terrain and obvious spatial heterogeneity of ESs, and was selected as the study area. In this study, we used the fuzzy k-means (FKM) algorithm to establish LHUs. Three major ESs (water yield, net primary productivity (NPP), and soil conservation) in 2000 and 2015 were quantified using the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) model and Carnegie Ames-Stanford approach (CASA) model. Then, we explored the spatial variation in ESs along terrain gradients and LHUs. Correlation analysis was used to analyze the driving factors of ESs in each terrain region and LHU. The results showed that altitude and terrain niche increased along LHUs. Water yield and soil conservation increased from 696.86 mm and 3920.19 t/km2 to 1061.12 mm and 5117.90 t/km2, respectively, while NPP decreased from 666.95 gC/m2 to 648.86 gC/m2. The ESs in different LHUs differed greatly. ESs increased first and then decreased along LHUs in 2000. In 2015, water yield decreased along LHUs, while NPP and soil conservation showed a fluctuating trend. Water yield was mainly affected by precipitation, temperature and NDVI were the main drivers of NPP, and soil conservation was greatly affected by precipitation and slope. The driving factors of the same ES were different in different terrain areas and LHUs. The variation and driving factors of ESs in LHUs were similar to some terrain gradients. To some extent, LHUs can represent multiple terrain features. This study can provide important support for mountain ecosystem zoning management and decision-making.

Relationship between Residential Area Distribution and Terrain Factors

Taking residential area as the research object, combined with variable dimension fractal theory, the influence degree of different terrain gradient of elevation, slope and aspect on the number distribution of residential area is studied. The results show that: there are three order cumulative and variable dimension fractal distribution characteristics between the number of residential area distribution and elevation, and the second-order cumulative and variable dimensional fractal distribution between the number of residential area distribution and slope aspect and slope. The influence degree of each topographical factor on the number distribution of residential areas from high to low is slope aspect > slope > elevation.

Study on the Arctic Underwater Terrain-Aided Navigation Based on Fuzzy-Particle Filter

The ultra-low resolution underwater terrain maps of the Arctic region reduce the localization and navigation accuracy of the underwater vehicle relying on terrain-aided navigation. In this paper, we study the navigation ability of Autonomous Underwater Vehicles (AUVs) under the ultralow-resolution terrain map. Firstly, the low-resolution map is transformed into a continuous map by bilinear interpolation. Then, a Terrain-Aided Navigation (TAN) system based on the Particle Filter (PF) is constructed to estimate the state of AUV position by particles. Particles of a random distribution of fixed variance can effectively track targets. However, a fixed variance distribution is not well adapted to many different situations. To improve navigation accuracy and robustness, fuzzy logic is used to estimate the distribution variance of particles under the current terrain gradient dynamically. The simulation results show that our proposed Fuzzy-PF TAN system is robust under various current disturbance situations. The position error of our system is within a map resolution unit of 500 m.

High‐resolution flood precipitation and streamflow relationships in two US river basins

AbstractRelationships between rainfall and river discharge are important for governing flood characteristics and predicting flood impacts. Previous studies have examined these relationships, but they lacked the high‐resolution precipitation data necessary to analyse rainfall–streamflow correlations for individual flood episodes. The present study addresses this limitation by examining rainfall–streamflow relationships in two topographically and climatically different river basins: the Wabash River basin in Indiana and the Willamette River basin in Oregon, using high‐resolution, sub‐basin precipitation and discharge data. Results show that flood rainfall–streamflow relationships are highly spatially variable on a sub‐basin scale. In the Wabash basin, strong positive correlations exist between rainfall and streamflow near urban areas and slight terrain gradients during flash floods, while weaker correlations between rainfall and streamflow are observed in other areas of the basin and for slow‐rise floods. In the Willamette basin, strong positive slow‐rise flood rainfall–streamflow relationships occur in referenced gauges in the eastern, mountainous part of the basin, while strong negative correlations occur in non‐referenced gauges near reservoirs along the main rivers. Results suggest that in addition to high‐resolution rainfall variability, the influence of urbanization, topography and water management on flood rainfall–streamflow relationships needs to be considered in order to forecast local flood impacts better.

Terrain‐referenced navigation using a steerable‐laser measurement sensor

The benefits of GNSS have created dependencies on navigation in modern day aviation systems. Many of these systems operate with no backup navigation source. This makes the capabilities supported by precise navigation vulnerable. This paper investigates a contemporary approach to terrain-referenced navigation (TRN), used to preserve an aircraft’s navigation solution during periods of GNSS denial. Traditionally, TRN has been accomplished using a single measurement sensor pointed nadir to an aircraft. Although shown to be effective, this approach limits the achievable navigation accuracy by restricting the measurable terrain gradients to those below an aircraft. This paper explores an alternative approach to TRN that maximizes navigation information through optimal steering of a gimbaled laser. A Cramer-Rao lower bound analysis as well as a high-fidelity simulation establishes the utility of optimal steering while employing TRN. This original approach to TRN shows the order of magnitude improvements in navigation performance over existing methods.

基于地形梯度的南方丘陵山地带生态系统服务价值对城市化的空间响应——以粤北地区为例

南方丘陵山地带是我国华南和西南地区重要的生态安全屏障带，具有重大的生态保护意义，而在当今快速城市化的进程下，保障该地区的生态资源与生态稳定对于我国实现可持续发展具有十分重要的战略意义。以丘陵山地带的典型区域粤北为例，依据地形位指数将研究区划分为5个地形梯度，并基于1990—2015年6期的土地利用遥感数据和社会经济的统计数据，利用地理信息技术和空间统计的方法，评估了粤北地区不同时期随地形梯度变化的各区域生态系统服务价值（Ecosystem service value，ESV）与城市化水平（Urbanization level，UL），之后探究了生态系统服务价值与城市化的空间相关性。研究结果表明：（1）1990—2015年期间，粤北地区城市化水平上升，且地形位指数为0.003—0.368的梯度1区域城市化水平最高。（2）研究期间粤北地区的生态系统服务价值呈轻微下降趋势，随着时间推移，ESV在低坡度、低海拔的地形梯度1区域下降率最高，而各个年份的ESV均随着地形梯度的升高而增加。（3）研究区自2000年后的土地利用类型转移的活跃程度加剧，其中主要是地形梯度1区域及周围的耕地、林地与建筑用地间发生转移。（4）空间相关性分析表明，粤北地区生态系统服务价值与城市化水平具有较强的负相关关系，且在研究期间负相关性明显增强；同时两者具有较显著的空间聚集效应，其中低ESV-高UL型集中分布于地形梯度1的韶关市与清远市区以及南雄市，高ESV-低UL型则分布在梯度相对较高、人口相对分散的少数民族自治县。研究探讨了粤北地区生态系统服务与城市化的时空关系并了解了各区域的发展模式，有助于进一步认识生态系统对于社会经济发展的支持作用，保持生态保护建设与经济发展的协调与平衡，从而保障和维护南方丘陵山地带的生态价值。;The southern hilly and mountainous region is an important ecological barrier in south and southwest China, which is of great significance for ecological protection. With the rapid development of urbanization, it is of great strategic significance to ensure the ecological resources and ecological stability in this region for the sustainable development of China. In this study, the north region of Guangdong was taken as the study area and divided into 5 terrain gradients according to the terrain index. Then we used data of land use and social economy from 1990 to 2015 and evaluated urbanization level and ecosystem service value (ESV) in the study area on the basis of the terrain gradient by using spatial statistical methods. In addition, we analyzed the spatial correlation between the ESV and urbanization level (UL) on the terrain gradient. The results showed that (1) during 1990—2015, the urbanization level in the study area showed an uptrend, and the level of urbanization was the highest in the gradient 1 region with the terrain index between 0.003 and 0.368. (2) During the study period, the ecosystem service value the study area showed a slight downward trend. As time went on, the decline rate of ESV was the highest in the terrain gradient 1 region. The ESV increased with the increase of the terrain gradient in each year. (3) After 2000, there was the highest active transfer of land use types in gradient 1 and its surrounding regions, among which the transfer was mainly between farmland, forestland and build-up land. (4) The spatial correlation analysis showed that there was a significantly negative correlation between urbanization level and ecosystem service value in the study area, and the negative correlation was significantly increased during the study period. At the same time, they had a significant spatial aggregation effect, in which the low ESV-high UL type was concentrated in Shaoguan urban districts, Qingyuan urban districts and Nanxiong City of terrain gradient 1, and the high ESV-low UL type was mainly distributed in the minority autonomous regions with a relatively dispersed population and higher terrain gradient. This research discussed the spatio-temporal relationship between ecosystem services and urbanization innorthern Guangdong and understood the development patterns of each region, which is helpful to further understand the supporting role of ecosystem in social and economic development. The purpose is to maintain the coordination and balance between ecological protection construction and urban development, so as to safeguard and maintain the ecological value of southern hilly and mountainous region.

Terrain gradient variations in ecosystem services of different vegetation types in mountainous regions: Vegetation resource conservation and sustainable development

Natural vegetation plays a vital role in ecosystem services, while anthropogenic land-use change causes extensive damage to natural vegetation, decreasing ecosystem services, and impacting human well-being. Therefore, it is of great significance to establish protected areas and implement vegetation protection measures. Ecosystem services depend on the vegetation type and terrain, but this topic has not been considered in detail in policy implementations. In this study, the Integrated Valuation of Ecosystem Services and Trade-offs (InVEST) model was used to evaluate water yield, carbon storage, soil conservation, and water purification in the Chuan-Dian ecological shelter. Statistical methods were applied to analyze the differences in ecosystem services of different vegetation types and determine spatial variations in ecosystem services along terrain (altitude, slope, landform relief, and terrain niche) gradients. The results showed that ecosystem services differed for different vegetation types, and natural forests provided higher ecosystem services than other vegetation types, except for water yield. The rational allocation of forests, shrubs, and grasses and the implementation of organic agriculture and agroforestry systems are important measures to ensure sustainable economic and ecological development. We used the ordered weighted average method to select priority conservation areas based on ecosystem services. The priority conservation areas can play an important role in vegetation management in mountainous regions. This study provides new perspectives for vegetation protection and sustainable development in large-scale mountain areas.

Comparison and Validation of Satellite-Derived Digital Surface/Elevation Models over India

India presents among the world’s most topographically complex geomorphologies, with land elevations ranging from –2 m to + 8586 m and terrain gradients sometimes exceeding 45°. Here, we present an evaluation of four freely available digital surface models (DSMs) on a model-to-model basis, as well as a validation using independent ground-truth data from levelled benchmarks in India. The DSMs tested comprise SRTM1″, SRTM3″, ASTER1″ and Cartodem1″ [an India-only model]. Along with these four DSMs, the MERIT3″ digital elevation model (DEM) is also tested with the ground-truth data. Our results for India indicate some mismatch of these DEMs/DSMs from their claimed accuracies/precisions. All DSMs/DEMs (except for ASTER) have > 90% of pixels satisfying ± 16 m at the one-sigma level, but only in the low-lying (< 500 m) parts of India, i.e. the Gangetic plains and the Thar desert.

Maximising the benefits of regulatory ecosystem services via spatial optimisation

Natural ecosystems provide essential regulatory services for local residents and provide benefits to human populations living outside a particular region through various transmission pathways. Accordingly, a spatially explicit conservation network is needed to protect key features from human disturbance. However, existing ecosystem protection surrogates have traditionally focused on biodiversity components or local ecosystem services (ESs). Additionally, conservation plans that protect the delivery value of an ES for regional, social and ecological security are lacking. Herein, we use a multi-objective optimisation method to design a conservation network that maximises the benefits of two regulatory ecosystem services (RESs) in a key eco-region, the Qinling Mountains of China. We identify a set of alternative conservation networks under different land restriction scenarios for both delivery and non-delivery RESs. Our planning results reveal clear spatial distinction between ES delivery and non-delivery values. Moreover, planning focusing on ES non-delivery values tends to ignore several areas that transmit important regulatory functions to downstream conurbations . Based on comparison of ES distribution, biodiversity richness, and existing nature reserves, we suggest that ES delivery values, especially those flowing along a terrain gradient, should be selected as a key protection proxy to complement nature conservation decisions associated solely with biodiversity indicators .