Landscape change patterns at three stages of the construction and operation of the TGP

AbstractAnalyses of landscape change patterns that are based on elevation and slope can not only provide reasonable interpretations of landscape patterns but can also help to reveal evolutionary laws. However, landscape change patterns and their model in different landforms of the typical watershed in the Three Gorges Reservoir Area (TGRA) has not been quantified and assessed effectively. As a complex geographical unit, the ecological environment in the middle reach of the Yangtze River has experienced great changes due to the construction of the Three Gorges Project (TGP) and its associated human activities. Here, based mainly on a digital elevation model (DEM) and remotely sensed images from 1986, 2000, 2010, and 2017 and by using GIS technology, speeds/ trends of landscape change, the index of landscape type change intensity, landscape pattern indices, and landscape ecological security index, the spatial and temporal evolution characteristics of different elevations, slopes, and buffer landscape types were analyzed in typical watersheds, as well as an evolutionary model of the landscape pattern. The results indicated that (1) the landscape types along with the land classification and buffer zone that were influenced by the TGR construction have undergone a phased change, with the period 2000–2010 being the most dramatic period of landscape evolution during the impoundment period; (2) landscape type shifts from human-dominated farmland to nature-driven forestland and shrub-land as elevations, slopes and buffer distances increased. The landscape has shifted from diversity to relative homogeneity; (3) land types and buffer zones played essential roles in the landscape pattern index, which is reflected in the differences in landscape type indices for spatial extension and temporal characteristics. The results of this paper illustrate the spatial–temporal characteristics of various landscape types at three distinct stages in the construction of the TGR. These findings indicate that the landscape ecological security of the watershed is improving year by year. The follow-up development of the TGRA needs to consider the landscape change patterns of different landforms.

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Characteristics of Landscape Change Patterns at Three Distinct Stages of the Construction and Operation of the Three Gorges Reservoir From 1986 to 2017

10.21203/rs.3.rs-112382/v1 ◽

2020 ◽

Author(s):

Ruikang Li ◽

Yangbing Li ◽

Bo Li

Keyword(s):

Landscape Pattern ◽

Landscape Change ◽

Three Gorges Reservoir ◽

Landscape Patterns ◽

Land Resource ◽

Three Gorges ◽

Study Region ◽

Landscape Type ◽

The Three Gorges Reservoir ◽

The Three Gorges

Abstract Analyses of landscape change patterns that are based on elevation and slope can not only provide reasonable interpretations of landscape patterns but can also help to reveal evolutionary laws. As a complex geographical unit, the ecosystem environment in the middle reach of the Yangtze River has experienced great changes due to the construction of the Three Gorges Reservoir (TGR) and its associated human activities. Here, based mainly on a digital elevation model (DEM) and remotely sensed images from 1986, 2000, 2010, and 2017 and by using GIS technology, buffer analysis, landscape element change and landscape pattern indices, the spatial and temporal evolution characteristics of different elevations, slopes, and buffer landscape types were analyzed in a typical watershed, as well as an evolutionary model of the landscape pattern. The results indicated that (1) the landscape elements along the land classification and buffer zone that were influenced by the TGR construction have undergone a phased change, with the period 2000-2010 being the most dramatic period of landscape evolution during the impoundment period; (2) landscape type shifts from human-dominated farmland to nature-driven forestland and shrub-land as elevations, slopes and buffer distances increased. The landscape has shifted from diversity to relative homogeneity. (3) land types and buffer zones have exhibited a significant effect on the landscape pattern index, which is reflected in the differences in landscape type indices for spatial extension and temporal characteristics. The results of this study illustrate the pronounced effect of the TGR on landscape patterns, and these findings will elucidate the scientific basis and provide a reference for sustainable land resource management in the study region.

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Effects of Landscape Positions and Landscape Types on Soil Properties and Chlorophyll Content of Citrus in a Sloping Orchard in the Three Gorges Reservoir Area, China

Sustainability ◽

10.3390/su13084288 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4288

Author(s):

Siyue Sun ◽

Guolin Zhang ◽

Tieguang He ◽

Shufang Song ◽

Xingbiao Chu

Keyword(s):

Soil Properties ◽

Chlorophyll Content ◽

Three Gorges Reservoir ◽

Slope Position ◽

Three Gorges Reservoir Area ◽

Three Gorges ◽

Reservoir Area ◽

The Three Gorges Reservoir ◽

The Three Gorges ◽

Landscape Types

In recent years, soil degradation and decreasing orchard productivity in the sloping orchards of the Three Gorges Reservoir Area of China have received considerable attention both inside and outside the country. More studies pay attention to the effects of topography on soil property changes, but less research is conducted from the landscape. Therefore, understanding the effects of landscape positions and landscape types on soil properties and chlorophyll content of citrus in a sloping orchard is of great significance in this area. Our results showed that landscape positions and types had a significant effect on the soil properties and chlorophyll content of citrus. The lowest soil nutrient content was detected in the upper slope position and sloping land, while the highest exists at the footslope and terraces. The chlorophyll content of citrus in the middle and upper landscape position was significantly higher than the footslope. The redundancy analysis showed that the first two ordination axes together accounted for 81.32% of the total variation, which could be explained by the changes of soil total nitrogen, total phosphorus, total potassium, available nitrogen, available potassium, organic matter, pH, and chlorophyll content of the citrus. Overall, this study indicates the significant influence of landscape positions and types on soil properties and chlorophyll content of citrus. Further, this study provides a reference for the determination of targeted land management measures and orchard landscape design so that the soil quality and orchard yield can be improved, and finally, the sustainable development of agriculture and ecology can be realized.

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