Green Infrastructure Offset the Negative Ecological Effects of Urbanization and Storing Water in the Three Gorges Reservoir Area, China

Abstract

Land use planning usually increases the uncertainties of the ecosystem structures and functions because various human demands usually bring both positive and negative ecological effects. It is critical for estimating various land use changes and their ecological effects, but the previous studies have failed to decouple the respective and the combined effects of different land use changes on ecosystem services. Net primary productivity (NPP) could be used to indicate many ecosystem services such as carbon sequestration and storage. Here, we employed a light use efficiency model to estimate the spatial and temporal dynamics of NPP in the Three Gorges Reservoir (TGR) area from 2000 to 2015, and designed four scenarios to analyze the relative roles of afforestation, urbanization and storing water on NPP dynamics. Our results documented that terrestrial NPP of the TGR area increased from 547.40 gC•m−2 to 629.96 gC•m−2, and carbon sequestration capacities were 31.66 TgC (1Tg = 1012g) and 36.79 TgC in 2000 and 2015, respectively. Climate change and land use change both could contribute to carbon sequestration with 4.08 TgC and 1.05 TgC. Among these land use changes, only afforestation could sequester carbon with 2.04 TgC, while urbanization-induced and impoundment-induced emissions were 0.12 TgC and 0.32 TgC, respectively, and other land use changes also could release 0.55 TgC of carbon. This finding suggested that although positive and negative environmental effects happened simultaneously over the past decades, green infrastructure could effectively offset the carbon emissions from urbanization and storing water in the TGR area, which provides some fundamental supports for further ecological restoration and contributes to empowering land use policies towards carbon sequestration and storage at the regional scale.

Landscape Dynamics Improved Recreation Service of the Three Gorges Reservoir Area, China

“…Correspondence analysis is a data analysis model that attempts to consider the distance between study objects by combining classification methods with graphical modeling [31,41,42]. This method was employed to identify the relationship between the landscape changes and the recreation services changes.…”

“…The TGRA has both unique natural landscape resources and high-grade human landscape resources, which contributes to a region of high-quality tourism resources. But the high-intensity vegetation destruction in the past decades and the barren hills on both sides of the Yangtze River have seriously affected the scenery of the reservoir area [31]. If effective measures are not taken in time, it will not only cause the waste of tourism resources but will also be detrimental to economic development.…”

“…Tourism infrastructure (e.g., road network density and grade) and hospitality facilities (e.g., hotels) are lagging. Therefore, it is necessary to vigorously advocate ecological tourism in the reservoir area and strengthen infrastructure construction to improve the utilization rate of natural and humanistic tourism resources and promote the economic development of the TGRA [31]. However, with the impoundment of the Three Gorges Dam and the increase in water level in the reservoir area, some humanistic landscapes, such as Zhang Fei Temple, have been submerged.…”

The Impact of Urban Development Intensity on Ecological Carrying Capacity: A Case Study of Ecologically Fragile Areas

“…The Three Gorges Reservoir Area (Chongqing section) is mainly located at the end of the upper reaches of the Yangtze River [ 40 , 48 ]. Geographical coordinates range from 28°28′–31°44′ N and 105′N°49′–110°12′ E. It involves 22 districts and counties in Chongqing, starting from Jiangjin District in the west, Wushan County in the East, Wulong District in the south, Wuxi County, and Kaizhou District in the north, as shown in Figure 1 .…”

“…The Three Gorges Reservoir Area (Chongqing section) [ 38 , 39 ] is located in the upper reaches of the Yangtze River, accounting for more than 85% of the whole Three Gorges Reservoir area. As an ecotone of the karst landscape ecosystem and the karst forest ecosystem in Southwest China, the Three Gorges Reservoir Area (Chongqing Section) is a typical ecologically fragile area [ 6 , 40 ]. Due to the complex geological conditions, the area is easily affected by various natural disasters, e.g., landslides, bank collapses, debris flows, etc.…”