Browsing by Author "Liu, Yanxu"
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Item Open Access Applying ant colony algorithm to identify ecological security patterns in megacities(Elsevier, 2019-03-20) Peng, Jian; Zhao, Shiquan; Dong, Jianquan; Liu, Yanxu; Meersmans, Jeroen; Li, Huilei; Wu, JianshengEcological security patterns composed of ecological sources and corridors provide an effective approach to conserving natural ecosystems. Although the direction of ecological corridors has been identified in previous studies, the precise range remains unknown. To address this crucial gap, ant colony algorithm and kernel density estimation were applied to identify the range and restoration points of ecological corridors, which is important for natural conservation and ecological restoration. In this case study of Beijing City, ecological sources were identified based on habitat importance and landscape connectivity. The results showed that, in total 3119.65 km2 of ecological land had been extracted as ecological sources, which were mainly located in the northern, northwestern and northeastern mountainous areas. The identified key ecological corridor covered an area of 198.86 km2, with 567.30 km2 for potential ecological corridors, both connecting the ecological sources. 34 key points were also identified with priority in restoring ecological corridors.Item Open Access Linking ecosystem services and circuit theory to identify ecological security patterns(Elsevier, 2018-07-11) Peng, Jian; Yang, Yang; Liu, Yanxu; Hu, Yi'na; Du, Yueyue; Meersmans, Jeroen; Qiu, SijingThe rapid process of urbanization, accompanied by the sharp increase of urban population and expansion of artificial surface, has resulted in the loss of natural ecosystems and the degradation of ecosystem services. Identifying and protecting key places that have high importance for ecological sustainability are great challenges. Ecological security patterns are such an integrated approach to protecting regional ecological sustainability. In this study, taking Yunnan Province, China as a case study area, ecological sources were identified through ecosystem services, and circuit theory was used to model ecosystem processes in heterogeneous landscapes via calculating the ‘resistance’ or ‘current’, and thus to identify ecological corridors and key ecological nodes. The results showed that, ecological security patterns included 66 ecological sources, 186 ecological corridors, 24 pinch-points and 10 barriers. In details, the ecological sources were mainly distributed in the southwest and northwest of Yunnan Province, with the ecological corridors locating along the high mountains, and both ecological sources and corridors were mostly covered with forest land. Pinch-points covered by forest land and cultivated land, were distributed in the middle of Yunnan Province along the rivers. Approximately 75.9% nature reserves were located in the identified ecological sources, and the remainings were mainly distributed in eastern Yunnan Province with small area, showing the effectiveness in identifying ecological security patterns. Among 81 projects of low–slope hill development carried out in Yunnan Province, 46.9% showed potential human stress on regional ecological security. Based on ecosystem services and circuit theory, this study provides a new approach to identifying the spatial range of ecological corridors and the specific location of key nodes for effective ecological conservation and restoration.Item Open Access Multifunctional landscapes identification and associated development zoning in mountainous area(Elsevier, 2019-01-04) Peng, Jian; Hui, Xiaoxu; Qiu, Sijing; Hu, Yi'na; Meersmans, Jeroen; Liu, YanxuMultifunctional landscape has become a new discipline growth point in landscape ecology. Globally mountainous areas occupy about one fifth of Earth's surface. However, few studies focused on landscape multifunctionality in mountainous areas. Taking Dali Bai Autonomous Prefecture, China, as a case study area, five typical landscape functions (net primary productivity, soil retention, water yield, crop production, and residential support) were quantified and mapped. Hotspots of multiple landscape functions were identified using spatial overlap tools, interaction between each landscape function pair was discussed through Spearman's rank correlation analysis, and development zoning was conducted based on landscape function bundle. The results showed that, about 61% of the study area had at least one kind of landscape function hotspot, with only 2.7% covering three or more kinds of landscape function hotspots. Significant trade-offs or synergies existed between all pairs of landscape functions, except the pair of net primary productivity and residential support. With the application of Self-Organizing Feature Maps (SOFM) method, the study area was divided into four types of development zones (i.e. ecological shelter area, ecological transition area, suburban development area, and urban agglomeration area) which were all corresponding to different landscape function bundles. This study could provide spatial guidance for differentiated sustainable developing in mountainous areas according to local conditions of landscape multifunctionality.Item Open Access Simulating the impact of Grain-for-Green Programme on ecosystem services trade-offs in Northwestern Yunnan, China(Elsevier, 2019-09-01) Peng, Jian; Hu, Xiaoxu; Wang, Xiaoyu; Meersmans, Jeroen; Liu, Yanxu; Qiu, SijingPrefecture in 2000, land use/cover has undergone dramatic changes. This study used the CLUE-S model to simulate land use change in 2030, and explored the spatial pattern and relationship of different ecosystem services under the four scenarios of GFGP. The results show that, GFGP can help to improve indirect services of ecosystems, such as carbon storage and soil conservation. However, direct services of the ecosystem will decline, such as food production and water yield. Compared with 2010, the overall supply level of the four ecosystem services is the most balanced in the moderate GFGP scenario. In this scenario, total food production decreased by 179,000 tons and water yield decreased by 57 million cubic meters. Carbon storage and soil conservation continued to grow, increasing by 21.86 million tons and 17.87 million tons, respectively. The changes of ecosystem services in the strong GFGP scenario are extreme. The increases in carbon storage and soil conservation are at the expense of a significant reduction in food production and water yield. It can be concluded that GFGP may lead to intensifying ecosystem services trade-offs. Through comparing the changes of ecosystem services under different GFGP scenarios, it is found that the implementation intensity of GFGP should be deeply concerned in policy making.