Wetland is one of the most important ecosystems in the world. A healthy wetland ecosystem is important to the development of a regional and even global economy, and it is also beneficial to the human living conditions. In this paper, remote sensing (RS), landscape metrics were used to analyze the land use/land cover change (LUCC), landscape pattern change and the ecosystem services value (ESV) from 1987 to 2017 in Nansi Lake wetland of China. The results showed: 54.4% of the natural wetlands in Nansi Lake were replaced by constructed wetlands in the past 30 years, the ecosystem was degraded and the landscape structure was fragmented due to the severe drought in 2002 and the development of aquaculture and tourism in recent years. The ESV of Nansi Lake wetland fluctuated from 1987 to 2017, and the average annual ESV ($8134/hm2) was much lower than that of global and China’s wetlands, the LUCC driven by human production and economic development leads to the reduction of ESV, especially the rapid increase of constructed wetlands. Finally, the implications of wetland laws and policies, wetland monitoring, assessment and database construction, and wetland regional development strategies were discussed for wetland protection and management.
Urban heat islands (UHIs) constitute an important ecological problem in cities. Ecological space has a positive effect on UHI mitigation, which can be effectively organized in the form of ecological networks. In this study, the framework for structural UHI improvement based on ecological networks considering the source-corridor model is proposed to examine the spatial threshold of the thermal effect of ecological network factors. Additionally, the cooling mechanism of each constituent element in the ecological network context is further explored. The results demonstrate that (1) an obvious cold and heat island spatial aggregation distribution exists in the Xuzhou main urban area, and land of the same land use type exhibits the dual thermal environmental properties of cold and heat islands through its spatial distribution and characteristics. Ecological space is the main bearing area of cold islands. (2) The ecological network in the main urban area of Xuzhou city occurs at a moderately complex level, and the overall network efficiency is acceptable; the network connectivity is low, while the network loop distribution is uneven. (3) Ecological networks represent an effective spatial means to improve overall UHI patterns. The ecological source area cooling threshold is 300 m, and the optimal threshold is 100 m, while the ecological corridor width threshold is 500 m and 60 m, respectively. (4) Within the optimal threshold in the context of ecological networks, the temperature of ecological sources in category G land is influenced by NDBI and FVC; ecological corridors are mainly influenced by NDBI. The results can provide a quantitative basis for urban ecological network planning considering UHI improvement and a reference for urban thermal environment research within different ecological substrates and planning and control systems in other countries and regions worldwide.
8 July 2019 in Polish Journal of Environmental Studies
The exploitation and utilization of mineral resources bring changes of the regional material cycle and energy flow, resulting in degradation and negative evolution of the local ecosystem. Many countries are committed to researching ecological environment issues and have proposed a series of techniques and methods in recent years, but the comprehensive study of mining area ecosystems and restoration modes is not enough. To further clarify the mining area ecosystem and global restoration, this research analyzed the characteristics and functions of the ecosystem in mining areas, explored its evolution principles, types and processes, and put forward four typical ecological restoration modes. The mining area ecosystem features open, artificial and complex characteristics and special energy and material flows. Its functions mainly refer to the input and output of materials, energy, information and stream of people in the internal and external systems. The ecosystem evolution of mining areas consists of negative evolution and positive evolution in arid and semi-arid areas and humid and semi-humid areas. Overall, four typical restoration modes of mining area ecosystems are featured, including land engineering reclamation, soil improvement and vegetation restoration, secondary wetland construction and ecological self-restoration modes.