Integrating Ecosystem Function and Structure to Assess Landscape Ecological Risk in Traditional Village Clustering Areas
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sustainability Article Integrating Ecosystem Function and Structure to Assess Landscape Ecological Risk in Traditional Village Clustering Areas Sheng Liu 1,2,* , Ming Bai 3 and Min Yao 3 1 Department of Environment Design, Zhejiang University City College, Hangzhou 310011, China 2 College of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, China 3 Urban-Rural Planning & Design Institute, Zhejiang University, Hangzhou 310030, China; [email protected] (M.B.); [email protected] (M.Y.) * Correspondence: [email protected] Abstract: Land use in traditional village clustering areas often exhibits slight dynamic changes; however, significant hidden ecological hazards may be present in local settlements. There is still a lack of dynamic ecological risk assessments for the corresponding classification-based prevention strategies and landscape ecosystem attributes’ enhancement. Based on the land-use changes, this study integrated the ecosystem structure and function to explore the characteristics of the landscape ecological risk in traditional village clustering areas. The clustering area of 24 national traditional villages in Songyang County of Lishui City in Zhejiang Province, China, served as the study region to evaluate and analyze the changes in the landscape ecological risk from 2010 to 2019. The results showed that the land-use transitions were subtle but dominated by changes from forest cultivated land, posing high risk and medium—high risk increased slowly in size. Additionally, significantly Citation: Liu, S.; Bai, M.; Yao, M. increased risks were located mainly in the boundary area of the five villages. Moreover, 22 settlements Integrating Ecosystem Function and were found in the sensitive area with increased risks less than 600 m away. This assessment will Structure to Assess Landscape provide a basis for traditional villages’ risk prevention and ecosystem protection. Ecological Risk in Traditional Village Clustering Areas. Sustainability 2021, Keywords: ecological risk; ecosystem function; ecosystem structure; traditional village 13, 4860. https://doi.org/10.3390/ su13094860 Academic Editor: Carmela Cucuzzella 1. Introduction 1.1. Background Received: 1 March 2021 Traditional villages are usually villages with cultural heritages that take both material Accepted: 22 April 2021 and non-material forms; these villages offer non-renewable historical, cultural, architec- Published: 26 April 2021 tural, and research value [1]. In 2012, China started protecting single traditional villages, and in 2019, the protected objects expanded from single villages to village clusters, fo- Publisher’s Note: MDPI stays neutral cusing on the sustainable and healthy development of contiguous villages. Traditional with regard to jurisdictional claims in village cluster areas (TVCA) are delineated by Chinese local governments, according to published maps and institutional affil- the protection boundary of the contiguous villages with high protection values [2]. They iations. are not administrative units but are of management significance for centralized protection and revitalization. The term landscape emerged around the sixteenth century, referring to the natural scenery in paintings [3]. From an ecological aspect, landscapes are spatially heterogeneous Copyright: © 2021 by the authors. geographical areas characterized by diverse interacting ecosystems, ranging from relatively Licensee MDPI, Basel, Switzerland. natural terrestrial to human-dominated environments [4,5]. In TVCA, the landscape This article is an open access article connects and protects each settlement’s living systems, and its sustainability is of great distributed under the terms and significance in ensuring a contiguous inheritance [6]. conditions of the Creative Commons However, due to different land policies in China, land use in TVCA is changing at Attribution (CC BY) license (https:// the microlevel. In some cases, due to the balance of arable land systems (BALSs) and the creativecommons.org/licenses/by/ Low-Yield Forest Reconstruction Project, some forest land has been turned into cultivated 4.0/). Sustainability 2021, 13, 4860. https://doi.org/10.3390/su13094860 https://www.mdpi.com/journal/sustainability Sustainability 2021, 13, 4860 2 of 16 land [7]. Other areas have benefited from the Grain-for-Green Project, leading to change from grassland to forest land [8]. These changes are usually subtle and not easy to perceive at the regional level; however, local dotted changes can easily cause major disasters for settlements, threatening the sustainable survival of traditional villages. For example, in the Su village in Lishui City of Zhejiang Province, China, satellite images starting in 2000 showed a reduction in the dotted mountain forest land at the edge of the village and the expansion of a rock exposure every year. However, the government had no scientific method of predicting ecological risk, so risk was continuously not addressed, and forest land was continuously reduced. As a result, in 2016, a geological disaster occurred, damaging the traditional environment, causing 27 deaths, and damaging 20 houses [9]. Given this background, this study addressed a core problem. Land use in TVCA exhibits slight dynamic changes, easily hiding major ecological risks in local settlements. There is a lack of scientific research on the features of this ecological risk in TVCA for prioritizing risk avoidance. An appropriate dynamic risk assessment is needed to effectively avoid damage to its ecosystems and prevent the occurrence of other derivative disasters. 1.2. Literature Review An ecosystem is a community of living organisms in conjunction with the nonliving components of their environment, interacting as a system [10]. It has many derivative concepts. For instance, a business ecosystem centers on a firm and its environment [11]; a soil ecosystem focuses on interaction among biomass, nutrient, and water [12]. A landscape ecosystem refers to the ecosystem at the landscape scale and is a hierarchical level of the ecosystem [13]. It is defined as the community developed through the interaction between the spatial and temporal patterns and the ecological processes [14]. Landscape ecological risk (LER) refers to the possible negative impact of the interac- tion between landscape pattern and ecological processes [15,16], while ecological risk is defined as the probability of occurrence of an undesired ecological impact [17]. The main difference between ecological risk, which frequently assumes that systems are spatially homogeneous, and landscape ecological risk is that the latter considers the spatial patterns and heterogeneity [18]. Past studies on landscapes in traditional villages have mostly focused on tourism development and forest management [19–21]. They have not fully addressed ecological risk in TVCA. Additionally, existing LER models have mainly focused on the cities, rivers, and roads [22–24], or areas delineated as a world cultural heritage area with a high protection value [25]. As the characteristics of these risks differ from those found in traditional villages, there is still a gap in this special LER assessment. The index method is the common method for conducting an LER assessment [24,26]. It is based on land use analysis and is constructed through the degree of landscape dis- turbance and fragility, using the paradigm of “multiplicative multiplication of loss and probability” to depict the spatial–temporal heterogeneity of risks. However, this method only uses the proportion of different land-use areas as the weight, leading to a lack of representation of ecological factors in risk probabilities [27]. Meanwhile, some studies have applied a “source-sink” method to evaluate specific risk sources, such as population growth and heavy metal contamination [28,29]. However, as this method is difficult to characterize the risk status of multisource stress, it reflects the comprehensive characteristics of LER in a relatively weak manner. Given the challenges associated with existing methods, the need for more feasible quantitative evaluation methods is highlighted. In summary, this study has addressed the following knowledge gaps: (1) Identifying the characteristics of the LER in TVCA; and (2) developing a comprehensive risk assess- ment method that can reflect both the multisource stress and the internal changes in the traditional villages’ landscape ecosystems. Solving these gaps could lead to the develop- ment of a scientific basis for prioritizing management practices that prevent and control ecological risks in TVCA. Sustainability 2021, 13, 4860 3 of 16 2. Methods 2.1. Study Area There are 6819 national-level traditional villages in China. Most are located in moun- tainous areas, with abundant forest and grassland resources, and are densely distributed in Guizhou, Yunnan, Hunan, and Zhejiang [30]. The middle area of Songyang County, Lishui City, Zhejiang Province in China was selected as the study area, and 24 national-level traditional village clustering areas in 6 townships were selected as the evaluation area, covering 114.39 km2 (Figure1). According to the hierarchical framework of ecological units [31], this size of landscape belongs to the subregion scale, referring to the county level. Figure 1. Study area. Zhejiang has a high level of economic development in China and has experienced significant changes in its land use. Lishui City is the area where the forest hand has decreased the most in Zhejiang Province [7]. Songyang County is the first demonstration