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1.
Likangala River catchment in Zomba District of Southern Malawi is important for water resources, agriculture and provides many ecosystem services. Provisioning ecosystem services accrued by the populations within the catchment include water, fish, medicinal plants and timber among others. In spite of its importance, the River catchment is under threat from anthropogenic activities and land use change. This paper studies land uses and land cover change in the catchment and how the changes have impacted on the ecosystem services. Landsat 5 and 8 images (1984, 1994, 2005 and 2013) were used to map land cover change and subsequent inventorying of provisioning ecosystem services. Participatory Geographic Information Systems and Focus group discussions were conducted to identify provisioning ecosystems services that communities benefit from the catchment and indicate these on the map.Post classification comparisons indicate that since 1984, there has been a decline in woodlands from 135.3 km2 in 1984 to 15.5 km2 in 2013 while urban areas increased from 9.8 km2 to 23.8 km2 in 2013. Communities indicated that provisioning ecosystems services such as forest products, wild animals and fruits and medicinal plants have been declining over the years. In addition, evidence of catchment degradation through waste disposal, illegal sand mining, deforestation and farming on marginal lands were observed. Population growth, urbanization and demand for agricultural lands have contributed to this land use and land cover change. The study suggests addressing catchment degradation through integrated method where an ecosystems approach is used. Thus, both the proximate and underlying driving factors of land-use and land cover change need to be addressed in order to sustainably reduce ecosystem degradation.  相似文献   

2.
Artificial surfaces, characterized with intensive land-use changes and complex landscape structures, are important indicators of human impacts on terrestrial ecosystems. Without high-resolution land-cover data at continental scale, it is hard to evaluate the impacts of urbanization on regional climate, ecosystem processes and global environment. This study constructed a hierarchical classification system for artificial surfaces, promoted a remote sensing method to retrieve subpixel components of artificial surfaces from 30-m resolution satellite imageries(Globe Land30) and developed a series of data products of high-precision urban built-up areas including impervious surface and vegetation cover in Asia in 2010. Our assessment, based on multisource data and expert knowledge, showed that the overall accuracy of classification was 90.79%. The mean relative error for the impervious surface components of cities was 0.87. The local error of the extracted information was closely related to the heterogeneity of urban buildings and vegetation in different climate zones. According to our results, the urban built-up area was 18.18×104 km2, accounting for 0.59% of the total land surface areas in Asia; urban impervious surfaces were 11.65×104 km2, accounting for 64.09% of the total urban built-up area in Asia. Vegetation and bare soils accounted for 34.56% of the urban built-up areas. There were three gradients: a concentrated distribution, a scattered distribution and an indeterminate distribution from east to west in terms of spatial pattern of urban impervious surfaces. China, India and Japan ranked as the top three countries with the largest impervious surface areas, which respectively accounted for 32.77%, 16.10% and 11.93% of the urban impervious surface area of Asia. We found the proportions of impervious surface and vegetation cover within urban built-up areas were closely related to the economic development degree of the country and regional climate environment. Built-up areas in developed countries had relatively low impervious surface and high public green vegetation cover, with 50–60% urban impervious surfaces in Japan, South Korea and Singapore. In comparison, the proportion of urban impervious surfaces in developing countries is approaching or exceeding 80% in Asia. In general, the composition and spatial patterns of built-up areas reflected population aggregation and economic development level as well as their impacts on the health of the environment in the sub-watershed.  相似文献   

3.
刘正文  苏雅玲  杨柳 《湖泊科学》2020,32(5):1244-1253
湖沼学是研究内陆水体的多学科交叉综合性科学,自从Forel F.A.于1892年首次对湖沼学做出定义以来已有近130年历史.湖沼学的主要分支学科包括地质湖沼学(包括古湖沼学)、物理湖沼学、化学(生物地球化学)湖沼学和生物湖沼学.湖沼学的关键自然属性是通过跨学科的整合,从水生态系统水平综合分析相关过程与机理,并对生态系统变化进行预测.因此,湖泊学也是支撑水资源与生态系统保护、管理与修复的核心科学.然而,目前我国湖沼学发展面临分支学科发展不平衡、研究碎片化等问题,而人类活动加剧和气候变化对内陆水体生态系统的影响及管理对策是湖沼学研究面临的挑战与机遇.我国湖沼学研究亟需围绕人类活动、气候变化的影响,重点开展以下几个方面的工作:1)水动力与水文地貌特征变化及其环境生态效应; 2)营养盐和有机质生物地球化学循环及其环境生态效应; 3)食物网结构与功能; 4)外来入侵物种的影响与控制对策; 5)与水环境有关的传染病防治; 6)地表水生态评价; 7)生态系统演变机理与退化生态系统修复等.  相似文献   

4.
Terrestrial ecosystems are both a carbon source and sink, therefore play an important role in the global carbon cycle that act as a link of interactions between human activities and climate changes[1,2]. Climate change impacts ecosystem carbon cycle through af- fecting biological processes, e.g. plant photosynthesis, respiration, and soil carbon decomposition. Land-use change directly modifies the distribution and structure of terrestrial ecosystems and hence the carbon storage and fluxes. Usi…  相似文献   

5.
A new method to simulate urban land-use dynamics is proposed based on multi-agent systems (MAS). The model consists of a series of environmental layers and multi-agent layers, which can interact with each other. It attempts to explore the interactions between different players or agents, such as residents, property developers, and governments, and between these players and the envi- ronment. These interactions can give rise to urban macro-spatial patterns. This model is used to simulate the land-use dynamics of the Haizhu district of Guangzhou City in 1995―2004. Cellular automata (CA) were also used for the simulation of land use changes as a comparison. The study indicates that MAS has better performance for simulating complex cities than CA.  相似文献   

6.
林芷欣  许有鹏  代晓颖  王强  袁甲 《湖泊科学》2018,30(6):1722-1731
针对城市化对平原河网水系结构的影响所引起的洪涝灾害频发等一系列水文问题,以我国典型平原河网地区苏州市为例,根据不同城市化程度分为主城区、市辖区、其他市县区,基于1991、2001和2015年三期遥感影像与1960s、1980s和2010s三个时期的水系数据,应用RS/GIS等技术,构建水系结构参数指标,重点探讨了城市化对河网水系结构及功能的影响.结果表明：城镇用地迅速增长,主要以牺牲水田、水域等土地利用方式为代价,到2015年全区城镇用地面积所占比重已达到41.35%,土地利用类型的变化规律与城市化进程的差异性保持一致;水系结构变化主要受城市化影响,且基本与城市化进程呈现同步性.近50年来,全区的水面率、河网密度、支流发育系数、主干河流面积长度比、河网复杂度和河网结构稳定度分别减少了19.63%、6.91%、7.34%、1.06%、5.49%和7.87%,城市化水平与各指数均呈负相关关系;人类活动不仅直接影响河流功能,也间接地通过改变平原河网的水系结构导致其功能发生改变,如河网调蓄能力下降、河流生态功能受损等.该研究为城市化地区河流水系保护及防洪减灾提供参考与理论支撑.  相似文献   

7.
Urban ecology is experiencing the third paradigm shift. To understand the interactions between the social system and the natural system in the city across time and space, and to provide theories and solutions to sustainable urban development are essential tasks for urban ecology in the next decade. Big data can play a crucial role in future urban ecology studies due to the interdisciplinary nature of urban ecology, the fact that cities are factories of big data, and the new insights gained by using big data in studies. Nevertheless, to translate big data from a concept to research results that can guide planning, policymaking, and management of cities, we need to overcome multiple challenges existing in the theoretical framework, data acquisition, and analytic methods. Urban ecologists should enhance the collaboration with the data scientists to increase the application of big data in studies of urban biodiversity, urban ecosystem services and human wellbeing, and processes of urban ecosystems.  相似文献   

8.
徐敏  董旭辉  羊向东 《湖泊科学》2014,26(3):331-339
当今在气候变化和人类活动等多重压力影响下,作为地表过程重要组成部分的湖泊生态系统正遭受着巨大威胁,其服务功能急剧退化.如何客观地评价湖泊生态系统服务的现状,并科学地预测其发展趋势,是当前亟待解决的问题.开展长期生态系统服务变化过程与机理的分析,有助于未来生态系统服务变化趋势的预测.然而,现有的观测数据往往时间较短(通常小于50年).连续的湖泊沉积记录为研究生态系统服务变化的长期过程提供了可能.本文结合前人研究成果,列举了可反映湖泊生态系统服务变化的一些古湖沼学指标,依据这些指标相对明确的生态和环境指示意义,将其与各项服务关联起来.最后,结合巢湖实例分析来说明这些指标在评估湖泊生态系统服务方面的具体应用,研究表明当今巢湖生态系统服务供应能力的持续增加是以调节服务的丧失为代价的.尽管目前的研究尚处于起步阶段,但古湖沼学手段无疑为今后湖泊生态系统服务历史状况的评估提供了途径,为古湖沼学的应用提供了一种新的思路,并为今后生态系统的保护和可持续利用提供重要的决策依据.  相似文献   

9.
Introductions of non-indigenous species (NIS) are mostly discussed through their impact on biodiversity. However, NIS can also act as ecosystem engineers, influencing the habitat itself, positively or negatively, directly or indirectly, which should be included when making risk assessments. Special concern should be given to changes in ecological services provided by the ecosystem. Physically, NIS may affect the substrate itself, or alter habitat architecture, indirectly influencing water movements, sediment accumulation, and light conditions. Chemical changes brought upon by NIS occur both on small and large scales, some having positive effects on ecosystem services, others can perturb epibionts. Furthermore, NIS may negatively affect natural resources, aquaculture or create fouling communities, all resulting in a negative impact on economics. However, if removed, already established NIS can be used as bioremediators, having a positive effect on different ecosystems. Using NIS for habitat management may be economically profitable, but could affect the habitat adversely.  相似文献   

10.
Waterlogging is one of the major water issues in most cities of China and directly restricts their urbanization processes. The construction of Sponge City is an effective approach to solving the urban water issues, particularly for the waterlogging. In this study, both the urban issues emerged at the stage of rapid urbanization in China and the demands as well as problems of Sponge City construction related with the water issues were investigated, and the opportunities and challenges for the Sponge City construction in the future were also proposed. It was found that the current stormwater management focused on the construction of gray infrastructures (e.g., drainage network and water tank) based on the fast discharge idea, which was costly and hard to catch up with the rapid expansion of city and its impervious surface, while green infrastructures (e.g., river, lake and wetland) were ignored. Moreover, the current construction of Sponge City was still limited to low impacted development (LID) approach which was concentrated on source control measures without consideration of the critical functions of surrounding landscapes (i.e., mountain, river, wetland, forest, farmland and lake), while application of the integrated urban water system approach and its supported technologies including municipal engineering, urban hydrology, environmental science, social science and ecoscape were relatively weak and needed to be improved. Besides, the lack of special Sponge City plan and demonstration area was also a considerable problem. In this paper, some perspectives on Good Sponge City Construction were proposed such as the point that idea of urban plan and construction should conform to the integral and systematic view of sustainable urban development. Therefore, both the basic theoretical research and the basic infrastructure construction such as monitoring system, drainage facility and demonstration area should be strengthened, meanwhile, the reformation and innovation in the urban water management system and the education system should also be urgently performed. The study was expected to provide a deeper thinking for the current Sponge City construction in China and to give some of suggestions for the future directions to urban plan and construction, as well as urban hydrology discipline.  相似文献   

11.
水生态系统是人类赖以生存的基础,近年来气候变化和水资源开发、水体污染、过度捕捞等人类活动导致水生态系统严重受损,水生态系统的保护和修复已成为全球面临的重大挑战。科学合理的水生态评价方法是实现水生态系统稳定、健康和可持续管理的基本保障,也是目前我国各相关管理部门高度重视的关键问题,多个部门围绕水生态评价展开了积极探索与实践。本文系统回顾了水生态评价方法的发展历程并阐释了水生态评价的内涵,梳理了常用的水生态评价方法,明晰了各方法的基本理念和应用场景,分析了各方法的优点和不足,提出了基于生态完整性的水生态健康评价方法,最后对目前我国水生态评价需进一步完善的工作进行了展望。本文以期与相关领域研究者和管理者在水生态评价理论和方法方面进行探讨,为我国水生态考核工作提供理论支持。  相似文献   

12.
This paper surveys approaches to the economic valuation of ecosystems and the determination of their optimal utilisation. The components of the value of ecosystems are defined and methods of measurement are presented. Also discussed is a simple model of the economic use of a dynamic ecological system. Economically optimal trajectories are shown and scenarios are presented in which it is economically optimal to destroy the ecosystem. Particular problems arise if the ecosystem is a common-property resource as is often the case with marine ecosystems. This issue is also addressed. Moreover, the paper presents some extensions of the model that add complexity and uncertainty.  相似文献   

13.
Understanding the multiscale impacts and drivers of urban agglomeration landscape patterns for ecosystem services (ESs), especially water-related ecosystem services (WESs), is essential for the development of regional ecological management. However, the multiscale impacts and driving mechanisms of urban agglomeration landscape patterns for ESs have not been adequately explained. In this study, multivariate data were employed, and the InVEST model, trend test method, coupled GeoDetector and geographically and temporally weighted regression (GTWR) method were utilized to comprehensively explore the spatial and temporal changes in landscape patterns and WESs in the Pearl River Delta urban agglomeration (PRDUA) at various grid and administrative scales from 1990 to 2020 and to determine the driving mechanisms affecting WESs. The results indicated that the variation characteristics of landscape patterns and WESs in the PRDUA were consistent, forming a binary spatial structure of core and peripheral areas in an inverted “U” shape around the estuary of the Pearl River. The relationship between landscape patterns and WESs weakened with the increase of scale, and the correlation coefficient decreased by approximately 0.10 from 5 km to 10 km grid scale. Additionally, precipitation (PRE) was the main factor controlling WESs changes in the PRDUA, explaining more than 50% of the changes in WESs, and the regression coefficients ranged from 0.0825 to 0.1584. Changes in WESs were the result of the combined effects of natural factors, including PRE, landscape pattern, elevation, slope, and socioeconomic factors, such as population and gross domestic product (GDP). Overall, these findings could contribute to optimizing regional landscape patterns and fostering sustainable development of the ecological environment in urban agglomerations.  相似文献   

14.
The biosphere of the Earth is the material founda-tion of human survival and development.With the increasing problems of the resources,the environment and population,most countries in the world have paid special attention to the measurement and evaluation of ecological capital,which refers to the sum of the direct natural resources value and the indirect ecosystem services value.Ecological capital depends on not only the quality of the national ecological environment,butalso the social recogni…  相似文献   

15.
The net ecosystem services value in mainland China   总被引：1，自引：0，他引：1  
Protection of the ecological environment is an effective strategy for maintaining ecosystem health,improving provision of ecosystem services,and increasing human well-being.However,traditional calculations of the value of ecosystem services(VES)provide weak guidance because they ignore the costs of these services,leading to economically inefficient strategies.To understand the difference between VES and the net ecosystem services value(NES,after subtracting costs from VES)and to improve evaluations of ecosystem services,we estimated NES for mainland China(including farmland,grassland,forest,and wetland).NES totaled 10.0×10~3RMB ha~(-1)yr~(-1)in 2014,which is only 35.1%of the corresponding VES.Grassland NES was–0.7×10~3RMB ha~(-1)yr~(-1),in contrast with a positive grassland VES.NES of farmland,grassland,forest,and wetland in2014 totaled 7.2×10~(12)RMB,accounting for 27.0%of China’s GNP.Recent Chinese planning based on VES emphasizes forest conservation and ignores the conservation of other important ecosystems,such as grassland,leading to a continuing loss of China’s natural capital.Due to regional differences in economic conditions,resource endowments,and geographical characteristics,VES and NES differ among regions.To maximize the ecological benefits from conservation,it is necessary to account for these differences by comparing strategies based on NES,thereby choosing projects that maximize both economic and ecological benefits.To maintain the ecological balance,ecological restoration and socioeconomic activities should account for the costs of providing ecosystem services.This is essential to minimize the costs and maximize the benefits of projects.  相似文献   

16.
It is well established that anthropogenic nutrient inputs harm estuarine seagrasses, but the influence of nutrients in rocky intertidal ecosystems is less clear. In this study, we investigated the effect of anthropogenic nutrient loading on Phyllospadix spp., a rocky intertidal seagrass, at local and regional scales. At sites along California, Washington, and Oregon, we demonstrated a significant, negative correlation of urban development and Phyllospadix bed thickness. These results were echoed locally along an urban gradient on the central California coast, where Phyllospadix shoot δ15N was negatively associated with Phyllospadix bed thickness, and experimentally, where nutrient additions in mesocosms reduced Phyllospadix shoot formation and increased epiphytic cover on Phyllospadix shoots. These findings provide evidence that coastal development can threaten rocky intertidal seagrasses through increased epiphytism. Considering that seagrasses provide vital ecosystem services, mitigating eutrophication and other factors associated with development in the rocky intertidal coastal zone should be a management priority.  相似文献   

17.
燕乃玲  虞孝感 《湖泊科学》2004,16(Z1):143-152
生态功能区划是我国正在开展的一项关于资源与环境管理的重大基础性工作.生态功能区划的理论和方法是当前生态学、环境科学、地理学等学科面临的一项新的热点课题.本文首先讨论了生态功能区划的概念,从认识区划看,生态功能区划属于生态系统区域划分的范畴,从实践的角度,则强调人文活动对生态系统可持续能力产生的影响,指出自然生态区不是生态功能区,生态功能区须反映人类的利用和价值判断.生态功能区划,不单是以自然要素或自然系统的"地带性分异"为基础,更是以生态系统的等级结构和尺度原则为基础,用生态系统完整性的评价测量人类活动对生态系统的影响,将生态功能区划的科学基础落在"基于生态系统的管理"平台上.文章提出了基于流域的我国生态功能区划的初步思想,讨论了区划的原则和方法,建立了生态系统完整性评价和功能区划分的指标体系.其基本内容是,认识并按照生态系统的自然边界划分生态系统单元;进行生态系统完整性评价;在此基础上划分不同的生态功能区,确定主导生态功能.  相似文献   

18.
Information entropy is introduced to describe the interactions between diverse agents in urban ecosystems. Basing on maximum information entropy method, a holistic structural parameter and its dynamic equation are derived to reflect urban ecosystem health (UEH). In this way, a new UEH assessment model has been proposed. We then apply the model to assess the UEH of Beijing, Dalian, Shanghai, Wuhan, Xiamen and Guangzhou in China. It is shown that the holistic structural parameter, the radar chart, and the associated correlations from the model can reveal the health features of different cities. According to the calculated ranges of the holistic structural parameter, a new UEH assessment grade standard is suggested and applied to the UEH assessment of some typical cities in China. It is demonstrated that the new model and the new assessment grade standard are precise and readily operational, which can be widely used in other urban ecosystems.  相似文献   

19.
精细的居民地数据对地震灾害风险分析具有重要意义。 为得到具有较高时效性与精细度的居民地数据, 充分发挥其对人口、 建筑物空间展布的指示作用, 本文综合利用多源遥感影像的优势, 基于分层分类思想开展城镇居民地识别与再分类研究。 以甘肃天水秦州区的主城区为例, 采用具有较高时效性的Landsat-8 OLI影像, 建立决策树分类模型识别出居民地轮廓; 在居民地轮廓内部, 进一步采用资源三号卫星(ZY3)高分影像, 利用面向对象方法进行居民地内部的建筑群再分类, 最后得到了具有不同精细程度的居民地数据。 实验结果中Landsat-8土地覆盖分类总体精度为92%(其中居民地识别率达86%), 城镇居民地再分类的总体精度为81%, 说明了本文研究方案的可行性。  相似文献   

20.
基于GIS的城市地质环境敏感性评价--以兰州市为例   总被引：3，自引：3，他引：3  
城市地质环境敏感性评价是城市可持续发展所要求的科学规划的基础．本文以兰州市为例，利用地理信息系统建立城市地质环境基础数据库．系统选取评价指标体系，采用专家赋值和层次分析法构建评价模型．结果表明基于GIS的评价模型可高效准确地进行城市地质环境敏感性评价．  相似文献   

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