Integrated watershed management:evolution,development and emerging trends

Watershed management is an ever-evolving practice involving the management of land, water, biota, and other resources in a defined area for ecological, social, and economic purposes. In this paper, we explore the following questions： How has watershed management evolved？ What new tools are available and how can they be integrated into sustainable watershed management？ To address these questions, we discuss the process of developing integrated watershed management strategies for sustainable manage- ment through the incorporation of adaptive management techniques and traditional ecological knowledge. We address the numerous benefits from integration acrossdisciplines and jurisdictional boundaries, as well as the incorporation of technological advancements, such as remote sensing, GIS, big data, and multi-level social-eco- logical systems analysis, into watershed management strategies. We use three case studies from China, Europe, and Canada to review the success and failure of integrated watershed management in addressing different ecological, social, and economic dilemmas in geographically diverse locations. Although progress has been made in watershed management strategies, there are still numerous issues impeding successful management outcomes; many of which can be remedied through holistic management approaches, incorporation of cutting-edge science and technology, and cross-jurisdictional coordination. We conclude by high- lighting that future watershed management will need to account for climate change impacts by employing techno- logical advancements and holistic, cross-disciplinary approaches to ensure watersheds continue to serve their ecological, social, and economic functions. We present three case studies in this paper as a valuable resource for scientists, resource managers, government agencies, and other stakeholders aiming to improve integrated watershed management strategies and more efficiently and successfully achieve ecological and socio-economic management objectives.

Extracting Lotus Fields Using the Spectral Characteristics of GF-1 Satellite Data

The lotus(Nelumbo nucifera Gaertn.)is an aquatic plant that grows in shallow water and has long been cultivated in South China.It can improve the incomes of farmers and plays an important role in alleviating poverty in rural China.However,a modern method is required to accurately estimate the area of lotus fields.Lotus has spectral characteristics similar to those of rice,grassland,and shrubs.The features surrounding areas where it is grown are complex,small,and fragmented.Few studies have examined the remote sensing extraction of lotus fields,and automatic extraction and mapping are still challenging methods.Here,we compared the spectral characteristics of lotus fields and other ground objects and devised a remote sensing method for the rapid extraction of lotus fields.Using this method,the extraction accuracy of lotus was 96.3%.The Kappa coefficient was 0.926,which is higher than those of the unsupervised K-means classification,Mahalanobis distance,and support vector machine supervised classification,and demonstrates the potential of this method for extracting and mapping lotus fields by remote sensing.

Carbon Emission Effect of Land Use in Nanchang City and Its Optimization Countermeasures

Land use/coverage change(LUCC)exerts a profound influence on global carbon emission through changing structure and functions of ecosystem.Taking Nanchang City as an example,this study determined organic carbon emission of land ecosystem by ecosystem type method.In 2005,total carbon emission of Nanchang City was 4.826 2 Tg.In 2010,it became 5.535 9 Tg,showing a growth trend of carbon emission from land use change.The carbon emission of cropland and grassland decreased in 2005-2010,that of garden land and construction land had increase,and carbon absorption function of water land and other unused land was weakened.Due to difference of land use structure,the carbon emission of Nanchang City is varied.In 2005-2010,the rank of carbon emission from high to low is as follows:Nanchang County,Xinjian County,Jinxian County and Qingshanhu District.In combination with land use change and development plan of Nanchang City,Nanchang City should take carbon emission reduction measures,including conceding the land to forestry,returning the land to water,limiting excessive expansion of construction land,optimizing distribution of urban land use,flexibly regulating land supply policies,and establishing carbon trading legal system,to reach the objective of combining land use plan with ecological construction.