Spatial evolution of traditional waterside settlements south of the Yangtze River and the distribution of settlement heritage: evidence from the Nanxi River Basin
Introduction
Research background
Traditional Chinese villages, particularly the Jiangnan water settlements, have received increased attention in recent years because of the global awareness of cultural heritage protection1. These settlements not only represent the basic essence of Chinese culture but also serve as a model of the complex interactions between humans and the natural environment throughout history2. In traditional Chinese culture, the Jiangnan water settlements are known for their unique natural geographical environment and rich historical heritage; they show the deep interweaving of people, water systems, terrain, and culture3. However, rapid urbanization and modern development pose a serious threat to the survival and continuation of these traditional settlements, and many villages are facing the risk of disappearing due to population loss, industrial changes, and cultural heritage interruption4.
Globally, policies and practices for protecting river basin settlement heritage have gradually developed that cover a variety of aspects, such as laws and regulations, technological innovation, community participation, and sustainable development. In 1972, the United Nations Educational, Scientific, and Cultural Organization (UNESCO) adopted the World Cultural and Natural Heritage Convention, which proposed a protection framework that combines cultural heritage with natural heritage5. In 2003, UNESCO adopted the Convention for the Safeguarding of the Intangible Cultural Heritage, which emphasizes the importance of intangible heritage in the protection of human civilization6. In 2012, China released the first list of traditional national villages, aiming to protect villages with historical and cultural values and emphasizing the holistic protection of settlements7. By the end of 2019, the Jiangnan region was home to many of the 6819 villages recognized as traditional national villages8, which underscores the region’s significance in China’s traditional cultural heritage.
Literature review
Research on river basin settlement heritage
In recent years, the research on river basin settlement heritage has focused on the long-term interactions between natural landscapes, especially water bodies and human settlements9. These settlement heritages are often closely connected to the surrounding water systems and are an important part of the cultural landscape that reflect historical, social, and ecological processes10. The literature increasingly emphasizes the need to protect and study river basin settlement heritage because of its vulnerability to natural changes and human interference11.
The research on river basin settlement heritage has investigated the following five aspects. First, an interactive relationship exists between settlements and the hydrological environment. Between 2002 and 2010, Chinese scholar Ling Xie examined land use data from oasis settlements in the upper reaches of rivers in Xinjiang’s dry region. He then used the CA-MAS and PLUS models to estimate how settlement land use change would affect river basin settlements in 2018 using cellular automata (CA)12. Similarly, Chinese scholar Han Zhou (2022) conducted a buffer zone analysis on the relationship between settlements and rivers in Hankou Town, Wuhan from 1635 to 1949 and quantitatively analyzed the spatiotemporal evolution relationship between water systems and historical settlement sites13. The second research focus involves examining the spatial structure and morphology of the settlement heritage. Researchers from China, led by Yan Zhao (2022), used geographic information systems (GIS)-sDNA and other tools to determine how the functional zoning of settlements in the Tianjin section of the Grand Canal was related to how different sections of the Grand Canal were classified14. Third, these researchers conducted an analysis of the basin’s ecological environment. Scholar Charles J. Vörösmarty (2018) noted that studying basin settlement protection is not just about safeguarding tangible and intangible heritage; it also concerns the overall environment, ecology, health, and sustainable human settlement space of the basin. Furthermore, basin settlement protection involves improving water resource management, building infrastructure along the water and highlighting how ecology and culture work together15. The fourth research focus is an increasing concern at the social and cultural level about the inheritance of intangible cultural heritage. A study in 2022 by Habtamu Mekonnen of the North Shoa District in Ethiopia’s Amhara region assessed how rituals, beliefs, and traditional knowledge affect religious heritage and historical culture16. Scholar Holly, Georgia (2022) further demonstrated through four case studies that the regional protection of river basin cultural heritage can effectively promote the development of East African coastal systems17. Fifth, the research focuses on river basin governance policies and strategies for heritage protection. Scholar Narendra Budi Hadi (2021) took Indonesia’s river basin management as an example and proposed a multiparty participation model for cultural heritage protection and ecological and community development18. In his study of Ethiopian river basin management practices, Fekadu Mengistu (2020) clarified the relationships among community perceptions, participation, adoption, and livelihood and considered strategies to alleviate river basin deterioration19.
In recent years, several scholars have revealed the fundamental role of the natural environment in the formation of waterside settlements through GIS analysis and noted the influence of cultural factors on the distribution of settlements. However, although these studies provide important insights, there is still a lack of in-depth analysis of the interaction between nature and culture, especially the special role of a closed environment in settlement protection and cultural inheritance.
Methods for analyzing river basin settlement heritage
The methods used to analyze river basin settlement heritage cover multiple disciplines and research tools. This study divides these methods into the following five categories: historical and archaeological analysis, GIS and remote sensing technology, ecological and environmental analysis, network ethnography and sociological analysis, and spatial morphological analysis (Table 1). Historical and archaeological methods reveal the historical evolution of settlements through excavation and historical document research, with a focus on the temporal depth of material remains20. Large-scale river basin land research typically employs GIS and remote sensing technology to provide detailed dynamics of settlement spatial layout and water system relationships through precise spatial data analysis21,22. Ecological and environmental analysis highlights the role of settlement ecological sustainability and traditional management systems in river basin environmental ecology research23,24. Researchers in social and human geography often employ network ethnography and sociological analysis to enhance their comprehension of social and cultural interactions within settlements, particularly the transmission of intangible cultural heritage25,26. Spatial morphology, a quantitative tool in the study of spatial structure types and evolution, analyzes the spatial functional structure of watershed settlements to reveal the relationships between water bodies and settlement layouts27,28.
Accordingly, although the research on river basin settlement heritage covers multiple disciplines, such as history, archaeology, GIS technology, the ecological environment, and social culture, there are still problems such as insufficient interdisciplinary integration, an overreliance on technology, relatively weak attention to intangible cultural heritage, insufficient dynamic adaptability research, and poor implementation of policies and protection practices. Current research has focused mostly on a single discipline or technical framework and lacks a comprehensive understanding of the cultural, ecological, and social dimensions and dynamic adaptation analysis. Future research needs to break through disciplinary boundaries by combining multidisciplinary methods such as history, geography, ecology, and sociology and by integrating quantitative and qualitative analyses. More attention should be given to how natural geographical conditions (such as water systems and topography), cultural factors (such as passing on intangible cultural heritage), and socioeconomic changes (such as population mobility and tourism growth) affect the formation and growth of settlements. This is especially true for a study that examines how Jiangnan water town settlements and heritage are spread out over space. This study conducts in-depth interdisciplinary research combined with GIS spatial analysis technology, field surveys and the dynamic tracking of the interactive relationships between settlements and both nature and culture. Through this approach, a comprehensive interpretation of the typical Jiangnan water town settlement heritage in the Nanxi River Basin and the formulation of sustainable protection strategies can be achieved.
Definition and mechanism analysis of intangible cultural heritage
As a cultural resource, intangible cultural heritage not only involves historical memory but also plays an irreplaceable role in the social, economic and cultural life of a settlement29. Scholar Siow-Kian Tan asserted that intangible cultural heritage (for example, traditional skills, folk activities, clan culture, etc.) is an important factor in maintaining the social structure and cultural identity of a settlement30. Studies have noted that intangible cultural heritage not only shapes the cultural atmosphere of a settlement at the historical level but also profoundly affects the spatial evolution of the settlement31. Chinese scholar Chen Kim Lim conducted a qualitative study on the attire of residents of different ethnic groups in Weld Quay, Penang, Malaysia, and verified that the residents’ clothing is a means of preserving intangible cultural heritage and a driving force for the local realization of the spirit of the place32. Similarly, scholar Khava Sh. Zaburaeva identified the cultural heritage of Northeast Caucasus ethnic groups as the core driving force for the sustainable development of settlements and cultural ecotourism33. Chinese scholar Bohua Li et al. summarized the operating mechanism of intangible cultural heritage and settlement space. Intangible heritage coexists in settlements as the recessive gene of settlement material space and expresses its cultural nature through a certain regular spatial language. Intangible heritage has a complex logical space that restores the order and structure of the physical space34. Accordingly, the literature focuses on the static description of intangible cultural heritage and lacks a systematic analysis of how it is dynamically integrated into the formation and evolution of settlements.
Problem statement and objectives
As a typical representative of waterside settlements in the Jiangnan region, the Nanxi River Basin has rich natural and cultural resources. Historically, its unique water system and topographic conditions have nurtured diverse settlement forms. Both natural factors (such as rivers and topography) and human factors (such as clan culture and traditional water conservancy management) influenced the spatial distribution and pattern evolution of the rural settlements in the Nanxi River Basin from the Neolithic Age (c. 10,000 B.C. to c. 2000 B.C.) to the Qing Dynasty (A.D. 1644–1911) in various periods. The unique spatial form and cultural landscape of the Jiangnan waterside settlements are a result of the intertwining of these natural and human factors. However, rapid urbanization and tourism development due to modernization have brought great challenges to the heritage protection of these ancient settlements. Frequent tourism development has threatened the spatial pattern of traditional settlements and the continuity of cultural heritage. To strike a balance between modern economic development and cultural heritage protection, it is crucial to understand the spatial evolution laws and inheritance of ancient settlements.
Traditional waterside settlements in the Jiangnan region have important cultural and historical value because of the interaction between their unique natural environment and social structure. As a typical region, the Nanxi River Basin has experienced the evolution of settlement patterns driven by geographical, cultural and economic factors in different historical periods. In recent years, research on waterside settlements has focused mainly on the impact of natural and cultural factors on settlement morphology35, but the discussion of the interaction between the two factors is still relatively limited. Some studies have proposed that settlement evolution is because of the joint shaping of the natural environment and human cultural activities36. However, the research generally ignores the special impact of the closed nature of the environment on cultural heritage inheritance. Compared with open basins, relatively closed environments, such as the Nanxi River Basin, provide different ways of interaction under natural conditions and in the cultural atmosphere, thus affecting the spatial distribution and cultural inheritance of settlements. The research on this environment is currently lacking, especially in the field of cultural heritage protection.
Therefore, this study uses the research framework of spatial evolution and cultural heritage distribution, draws on the application of technical methods such as GIS in heritage protection, and provides innovative suggestions on this basis. First, the study proposes a new concept of “relatively closed environments”, which is different from traditional open watershed analysis. A comparison of the settlement distribution and cultural heritage characteristics of other types of watersheds reveals the unique driving role of this environment in cultural heritage protection. Compared with other more open watershed environments, the relatively closed environment of the Nanxi River Basin provides a unique perspective from which to explore in depth how cultural heritage can be inherited and protected in a relatively closed natural background. Second, this study gives more attention to the deep-seated impact of intangible cultural heritage on spatial evolution and fills the gap in the existing research concerning this factor. Solving this problem is important for understanding the dynamic relationships among human activities, the environmental background and heritage protection. Therefore, the purposes of this study follow.
(1) The research team used GIS analysis methods to quantitatively analyze the distribution and evolution of settlements in different historical periods. As a typical traditional water town case south of the Yangtze River, the distribution patterns and spatial pattern evolution of rural settlements in the ancient (Neolithic-Qing Dynasty) Nanxi River Basin were analyzed in the “Neolithic Era” (c. 10,000 B.C.–2000 B.C.), “Eastern Han Dynasty” (25–220 A.D.), “Tang Dynasty – Five Dynasties” (618–960 A.D.), “Song Dynasty – Yuan Dynasty” (960–1368 A.D.), “Ming Dynasty” (1368–1644 A.D.) and “Qing Dynasty” (1644–1912 A.D.).
(2) The characteristics that affect the distribution of ancient settlements were examined, such as natural factors, human factors, and spatial characteristics, which are the result of the superposition of nature and humans.
(3) The role of intangible cultural heritage was explored as a driving force for the dynamic changes in settlements, and practical guidance and a reference are provided for heritage protection and regional sustainable development.
Research methods and data sources
Research location and typicality
Location analysis
This study focuses on the Nanxi River Basin in Yongjia County, Wenzhou City (Fig. 1a), Zhejiang Province, which is on the southeast coast of China, with geographical coordinates of 120°38′ to 121°15′ east longitude and 27°24′ to 28°04′ north latitude (Fig. 1b). It borders Yueqing and Huangyan to the east, Qingtian and Jinyun to the west, Xianju to the north, and faces Wenzhou across the river to the south. The Nanxi River is an important tributary of the Ou River, with a total length of approximately 141 km and a drainage area of approximately 2490 km2. Hills and mountains dominate the region’s topography. The terrain features of the high northwest and low southeast regions and the developed river network system together shape the typical distribution pattern of the Jiangnan water town settlements (Fig. 1c). The rich natural resources, especially the water system, have had a profound impact on the site selection, development, and layout of the settlements. The Nanxi River Basin is in a subtropical monsoon climate zone, with an average annual precipitation of approximately 1500 mm, a humid and mild climate, and a well-developed water system. These natural conditions provide basic support for the agricultural production and water transportation of the settlements. Buildings along the water, concentrated in river valleys and flat terraces, characterize the settlement distribution. The unique natural environment and long cultural heritage of the basin provide rich empirical evidence and research value for studying not only the spatial and temporal evolution of Jiangnan water settlements from the Neolithic Age to the Qing Dynasty but also the distribution of settlement heritage.
(Source: Drawn by the author).
Typicality analysis
The Nanxi River Basin has been the site of human activities since the Neolithic Age, and there are still Neolithic cultural relics, ancient towers, bridges, road pavilions, archways, and ancient battlefields from the Tang Dynasty (618–907 A.D.), Song Dynasty (960–1279 A.D.), Yuan Dynasty (1260–1368 A.D.), Ming Dynasty (1368–1644 A.D.), and Qing Dynasty (1644–1912 A.D.). Simultaneously, the Nanxi River Basin boasts ancient villages adorned with the “Seven Stars and Eight Dippers”, “Four Treasures of the Study”, and the concept of Yin-Yang Feng Shui. Additionally, numerous complete genealogies and family trees belong to the Hundred Family Names. These precious historical and cultural relics can help us understand the outline of the “farming and reading society” and “clan society” in ancient China. The time span from the Neolithic Age to the Qing Dynasty covers the entire settlement process from the initial formation to the mature development of the settlements in this area and provides a unique historical background for studying the spatial and temporal evolution of the settlements. The State Council of China approved this area as a national key scenic spot in 1988 and subsequently included it in the World Heritage Tentative List. Many historical villages are in the basin, such as Yantou Town and Furong Town. The layout of these settlements, which are built along the river, is highly consistent with the natural environment. In addition to its tangible cultural heritage (such as ancient buildings, bridges, and traditional water conservancy facilities), the Nanxi River Basin also retains a large amount of intangible cultural heritage, including traditional village feng shui positioning, clan culture, and opera art. These cultural elements continue the lifestyle of the historical settlements and reflect the spatial organization model of the harmonious coexistence between humans and nature.
The geographical characteristics of the Nanxi River Basin are relatively “closed”. The natural environment and social and economic activities in the basin are largely independent, which makes the settlement space evolution and cultural heritage in the area have distinct local characteristics. Particularly during the Ming and Qing Dynasties, the settlement form and inheritance of intangible cultural heritage in the Nanxi River Basin revealed unique multicenter characteristics, which sharply contrasts with the single-center settlements commonly found in open basins. The relatively closed environments of the Nanxi River Basin have promoted the in-depth inheritance and protection of local culture, especially in terms of intangible cultural heritage. The traditional skills, festivals, clan culture, etc., in the region have been inherited independently in this closed environment, which provides a unique perspective for the study of traditional waterside settlements. Therefore, the Nanxi River Basin is not only a research object as a geographical area but also an important typical case in the study of cultural heritage protection.
The Nanxi River Basin is different from other basins as a research object. Other basins, such as the Yangtze River Basin and the Yellow River Basin, have a loose distribution of settlements due to their open water systems and large basins, and the inheritance of cultural heritage in these areas is subject to a wider range of external influences. In contrast, the Nanxi River system and the surrounding mountainous areas form a relatively closed natural environment, which limits the penetration of external culture, thereby promoting the continuation and strengthening of local culture. Although other typical Jiangnan water towns (such as Suzhou and Hangzhou) also have high cultural heritage value, because of their relatively open geographical environment and more frequent cultural exchanges, the inheritance of cultural heritage in these areas is different from that in the Nanxi River Basin. In these areas, the inheritance of intangible cultural heritage is often strongly affected by external factors (such as foreign culture and the modernization process), while the cultural heritage of the Nanxi River Basin is more “self-enclosed”, which provides a special research object for studying the role of intangible cultural heritage in settlement evolution.
In addition, this study explored the role of intangible cultural heritage in the settlements of the Nanxi River Basin and the spatial and temporal relationships of settlement formation (Fig. 2), revealing the important contributions of intangible cultural heritage in shaping cultural identity, promoting the local economy, and enhancing community cohesion. We also examined the unique status of intangible cultural heritage in cultural heritage protection and proposed its sustainability and innovative functions as a “living heritage” in the development of contemporary settlements.
(Source: Drawn by the author).
Research methods and processes
This study explores the spatiotemporal distribution of ancient rural settlements in the Nanxi River Basin and its influencing factors by using a variety of methods, such as historical documents, spatial analysis, and field surveys (Fig. 3). First, map drawing and settlement annotation are performed. The researchers sorted the cultural heritage tables from the Neolithic Age (c. 10,000 B.C.–2000 B.C.) to the Qing Dynasty (1644–1912 A.D.) and annotated the settlements in which the cultural relics appeared. The researchers subsequently mapped the coordinates of the first appearance of rural settlements in six periods, namely, the Neolithic Era (c. 10,000 B.C.–2000 B.C.), Eastern Han Dynasty (25–220 A.D.), Tang Dynasty–Five Dynasties (618–960 A.D.), Song Dynasty–Yuan Dynasty (960–1368 A.D.), Ming Dynasty (1368–1644 A.D.), and Qing Dynasty (1644–1912 A.D.) in GIS and constructed a database of settlement heritage distribution points. Then, the researchers sorted the development trends of the settlements into different historical periods through an analysis of the natural geographical characteristics and the cultural environment. This study employed various spatial analysis methods, including kernel density analysis, the ellipse method, and spatial autocorrelation analysis, to uncover the aggregation pattern and center of gravity migration of settlements. Additionally, the influence of natural factors, such as distance, elevation, landform, slope, and slope aspect, on the settlement distribution was quantified through buffer zone analyses. Moreover, this study incorporated intangible cultural heritage into the analysis to explore its relationship with the spatial layout of settlements, especially the impact of traditional water management and religious rituals on settlement patterns. The research results provide a complete picture of how settlements in the Nanxi River Basin have changed over time and space and the factors that have shaped their growth. This gives us a way to think about protecting heritage and promoting sustainable development in similar areas.
(Source: Drawn by the author).
Kernel density estimation analysis
Kernel density analysis is a spatial statistical method used to calculate the distribution density of events or point data in a specific area37. This method helps reveal the spatial distribution characteristics of rural settlements in different historical periods and analyze their concentration and dispersion trends. It is an important tool for studying the spatiotemporal evolution of traditional waterside settlements south of the Yangtze River30. The formula is as follows:
where (fleft(xright)) represents the estimated value of the settlement density at spatial location (x), which indicates the density of the settlements near this point. (n) denotes the total number of settlements in the study area. ({x}_{i}) identifies a specific settlement location. The bandwidth parameter, (h), controls the degree of smoothing in the kernel density analysis.
Standard deviational ellipse analysis
Standard deviational ellipse (SDE) is a statistical method used to analyze the directionality and extent of spatial data38,39. By calculating the average center position and standard deviation of the point set, this method quantifies the main direction and extension range of the spatial distribution40. This study uses SDE to analyze the settlement distribution characteristics of the Nanxi River Basin in different historical periods (i.e., the Neolithic, Tang and Song, Ming and Qing, etc.), and calculates the standard deviation ellipse parameters through ArcGIS. This study sets the analysis to the standard deviation level that includes 68% of rural settlement patches41. The main calculation formula is as follows:
where ({SDE}x) and ({SDE}y) represent the centers of different rural settlement ellipses; (x)i and (y)i identify the spatial position coordinates of each rural settlement patch; (x)i and (y)i are the coordinates of patch (i); (bar{X}) and (bar{Y}) denote the average center of the patches; (n) is the number of all patches; (tan theta) represents the direction angle of the ellipse; ({sigma }_{x}) and ({sigma }_{y}) indicate the standard deviations of the X- and Y-axes, respectively; the X-axis in the north‒south direction is taken as the reference, as north is 0 degrees and rotates in a clockwise direction; and ({widetilde{x}}_{i}) and ({widetilde{y}}_{i}) signify the deviations of the average center and the XY coordinate axis, respectively. Then, the lengths of the major and minor semi-axes of the ellipse are determined.
Spatial autocorrelation analysis
Spatial autocorrelation analysis is used to quantify the similarities or differences between adjacent points in spatial data42. This method reveals the clustering or dispersion patterns of settlement data, identifies “hot spots” and “cold spots”, and thus analyzes the overall and local spatial distribution characteristics43. This study uses the global Moran’s I to identify the aggregation and dispersion of settlements in different historical periods. The Moran’s I index primarily quantifies spatial autocorrelation by measuring the degree of correlation of spatial phenomena and determining the degree of spatial aggregation or discreteness44. The formula is as follows:
The total number of settlement points is represented by (n). ({x}_{i}) and ({x}_{j}) are the observations at positions (i) and (j), respectively. (bar{x}) is the average of all data points. Spatial weight ({w}_{{ij}}) indicates the adjacency relationship between position (i) and position (j). ({S}_{0}={sum }_{i=1}^{n}{sum }_{j=1}^{n}{w}_{{ij}}) is the sum of the spatial weights. In the resulting analysis, (I ,>, 0) indicates positive spatial autocorrelation, that is, adjacent settlement points show similar properties (settlement concentration); (I=0) indicates that there is no obvious autocorrelation in space and that the settlements are randomly distributed; and (I ,<, 0) indicates negative spatial autocorrelation, that is, adjacent settlement points show dissimilar properties (settlement dispersion). In spatial autocorrelation analysis, variable x refers to the settlement coordinate data points of different eras.
Buffer zone analysis
When studying spatial data, buffer analysis is a commonly used spatial analysis tool to measure the spatial relationship between a specific point, line, or surface and the surrounding geographic features. Buffer zone analysis calculates the distance between a feature and other objects by generating a fixed distance area around a specified feature, thereby analyzing its spatial distribution and its impact on environmental elements. This study employed buffer zone analysis to measure the spatial correlation between settlements and both natural and cultural elements, including rivers, elevations, and intangible cultural heritage, in the Nanxi River Basin. We can evaluate the impact of both the natural environment and intangible cultural heritage on the location and layout of settlements by generating buffer zones at different distances. The formula is as follows:
where (d) is the distance between the target object and the environmental element, that is, the radius of the buffer zone. The coordinates of the settlement point are represented by (({x}_{1},,{y}_{1})), while the coordinates of the environmental and cultural elements are represented by (({x}_{2},,{y}_{2})). This study divides the buffering influencing factors into the four elements of elevation, slope, water system distance, and intangible cultural heritage sites. It sets buffer zones of different radii. This study refers to the buffer zone settings of the influencing factors of water system distance and intangible cultural heritage dissemination radius at the conventional county and city scales45,46 and then adjusts the matching interval value through sensitivity testing to obtain the division content in Table 2.
Data sources
The data sources used in this study include the following four types.
(1) Data collection from heritage protection sites and settlement sites. The researchers used the “Seventh Batch of County-level Cultural Relics Protection Units in Yongjia County” (https://data.wenzhou.gov.cn/jdop_front/detail/data.do?iid=12269&searchString=%E6%B0%B8%E5%98%89%E5%8E%BF) provided by the Yongjia County Natural Resources and Planning Bureau and the list of key villages and general villages for the protection and utilization of historical and cultural villages in Zhejiang Province in the Nanxi River Basin (the first to the eleventh batch). This list was requested by the Zhejiang Provincial Department of Agriculture to further organize six types of information as follows: ancient sites, ancient buildings, ancient tombs, grottoes and stone carvings, ancient cultural sites, and ancient villages. The researchers identified the earliest heritage of each settlement as its original spatial location.
(2) Onsite survey and confirmation. Based on settlement merging, clustering, and identification, the researchers identified a total of 262 ancient settlements. The researchers further verified the historical construction period of each settlement through continuous rural surveys, observed local chronicles and village chronicles in local ancestral halls and genealogies, and accurately determined the specific period to which each settlement belongs.
(3) Intangible cultural heritage site data. Based on the list of representative inheritors of intangible cultural heritage projects, intangible cultural heritage inheritance bases, and county-level intangible cultural heritage workshops in Yongjia County provided by the County Culture, Radio, Television, Tourism, and Sports Bureau of Yongjia County People’s Government (https://www.yj.gov.cn/art/2024/6/25/art_1229248200_4242789.html), the researchers merged the intangible materialized heritage projects into major categories (the merging standards are shown in Table 3) and established a database of intangible cultural heritage sites in the Nanxi River Basin.
(4) Nanxi River natural environment data. The digital elevation model (DEM) data come from the DEM data collected by the phased array L-band synthetic aperture radar (PALSAR) sensor of the Japanese ALOS Earth observation satellite, with a spatial resolution of 12.5 m (https://search.asf.alaska.edu/). We constructed watershed data based on the “Nanxi River Basin Water Conservancy Planning Revision Report” from the Yongjia County Water Conservancy Bureau. The Wenzhou City Data Open Platform (https://data.wenzhou.gov.cn/jdop_front/index.do), the Yongjia County Natural Resources and Planning Bureau, and the Yongjia County Statistical Yearbook provide the remaining natural environment data.
Results
Evolution of the spatiotemporal distribution of ancient settlement heritage
Distribution of ancient settlement heritage
The kernel density analysis of settlements in each dynasty reveals the spatiotemporal evolution of settlement hotspots. The distribution and development of ancient settlements in the Nanxi River Basin expand. Figure 4 shows that (1) from the Neolithic Era (c. 10,000 BC–2000 BC) to the Qing Dynasty (AD 1644–AD 1912), the spatial pattern development shifted from single-point concentration to multipoint diffusion, and the spatial location changed from the downstream estuary location. The development trend along the middle and upper reaches of the river basin has led to a shift in the settlement structure from scattered villages to an aggregation model of concentrated villages. (2) In terms of distribution trends, the distribution of ancient settlement heritage in the Nanxi River Basin has undergone significant evolution in both time and space, reflecting socioeconomic changes and the adaptability of the natural environment in various historical periods. The settlements gradually expanded from early concentration in the southern basin to the entire basin and reached their peak number and spatial distribution during the Qing Dynasty. (3) According to changes in the development period, the Neolithic and Eastern Han Dynasties were the initial periods of settlement heritage development. The Tang-Five Dynasties and the Song, Yuan, and Ming Dynasties were the periods of rapid settlement growth. The upper and middle reaches of the Nanxi River served as the concentration points for settlement construction. By the time of the Qing Dynasty, settlement development was at its peak. Many settlements were concentrated in the middle reaches of the Nanxi River and were distributed in a divergent shape, establishing the overall spatial pattern of traditional rural settlements in the Nanxi River.
(Source: Drawn by the author).
A total of 204 traditional settlements appeared in the Nanxi River Basin from the Neolithic Age to the Qing Dynasty, and the development speed of the ancient settlements in each period differed (Table 4). Specifically, (1) during the Neolithic Era (c. 10,000 B.C.–2000 B.C.), eight settlements emerged, which were primarily scattered villages. These settlements were concentrated on Nancheng Street and Sanjiang Street in the lower reaches (southern part) of the Nanxi River, indicating the emergence of a spatial human settlement pattern. (2) During the Eastern Han Dynasty (25–220 A.D.), four settlements appeared, which were mainly distributed in the Sanjiang Street area (Nanxi River estuary), with a focus on the development of downstream fishing and animal husbandry activities. (3) During the Tang Dynasty–Five Dynasties (618–960 A.D.), 16 settlements appeared, and the overall distribution began to develop toward the middle and was concentrated in Fenglin Town (middle), on Nancheng Street and on Sanjiang Street (downstream) for two blocks. The settlement heritage began to show an early complete settlement system and fortress defense system. (4) During the Song Dynasty–Yuan Dynasty (960–1368 A.D.), 30 settlements appeared, which were concentrated in the middle reaches of the Nanxi River, and developed toward Yantan Town, Sihaishan, and Hesheng Town in the upper reaches. The distribution pattern began to shift from scattered villages to collective villages, with strong clan clusters for mutual protection, marriage exchanges, and the development of the settlement scale and structure. (5) During the Ming Dynasty (1368–1644 A.D.), 25 settlements appeared, and settlement construction declined. The focus was on the development of the middle and lower reaches of the settlement space, especially the relationship between the estuary of Huangtian Street and the trade liaison of Yongjia County. (6) During the Qing Dynasty (1644–1912 A.D.), 121 settlements appeared, which represented the peak of the development of the Nanxi River Basin. During this period, a multicenter diffusion distribution was observed. The settlements were concentrated mainly in Fenglin Town, Yantou Town, and Daruoyan Town. The settlement village layout was strengthened again. The main basin of the Nanxi River was home to many settlements. The settlements engaged in extensive social, economic, and cultural exchanges. The settlements utilized the three functions of farming, academies, and clan studies to spread culture. Settlement security and resistance to war and turmoil were carried out in the form of group enclosures. In addition to the middle reaches of the Nanxi River, scattered settlements began to appear in other tributaries along the river basin.
Spatiotemporal evolution of settlement heritage
The researchers analyzed the spatiotemporal migration route of the center of gravity of ancient settlements in the Nanxi River Basin and the distribution characteristics of the center of gravity during different periods. The researchers obtained the following results based on the position of the center of gravity, its spatial expansion range, and the analysis of elliptical variance data in each period. (1) The settlement distribution in the Nanxi River Basin has experienced significant evolution over time and space. (2) The migration route of the center of gravity indicates that, as history progressed, the spatial distribution of settlements gradually expanded from the south to the north and east, and only reverted to the south during the Ming and Qing dynasties. On the basis of Fig. 5’s gravity center migration route, in the Neolithic Age, the settlement center of gravity was concentrated in the southern part of the basin (28.15°N, 120.69°E), indicating that early human activities primarily took place in low-elevation areas near water sources. Afterwards, the center of gravity of the settlement gradually shifted northward. During the Eastern Han and Tang Dynasties, the center of gravity changed less and remained in the central area of the basin (28.15°N, 120.68°E, and 28.35°N, 120.73°E), which suggests that the settlement distribution during this period was relatively concentrated. By the time of the Song and Yuan Dynasties, the center of gravity had shifted significantly to the north and east (28.51°N, 120.77°E) and showed a significant expansion of the settlement distribution area. During the Ming and Qing dynasties, the center of gravity shifted slightly southward, signifying that the settlements in the basin returned to the southern and central areas during these periods. (3) The standard deviation distance (StdDist) and direction of expansion in each time period (Table 5) reveals that during the Neolithic Age and Eastern Han Dynasty, the settlements were closer together (7.59 km and 14.15 km, respectively). This means that the settlement distribution range was more concentrated during these times. From the Tang to the Song and Yuan Dynasties, the standard deviation distance increased rapidly to 25.51 km and 26.73 km, which shows that the settlement distribution in the basin expanded significantly during this period, especially during the Song and Yuan Dynasties when settlements developed to the north and east. However, during the Ming and Qing Dynasties, there was a slight decrease in the standard deviation distance of the settlement distribution (18.61 km and 17.82 km), indicating a tendency for the settlement distribution to become more concentrated. During the Qing Dynasty, despite a significant increase in the number of settlements, their spatial distribution focused primarily on specific areas. (4) The expansion direction of the settlement distribution changes during different periods. During the Neolithic Age and Eastern Han Dynasty, the expansion directions remained relatively fixed at 173.80° and 173.15°, respectively, suggesting that early settlements primarily expanded along the north‒south axis. Since the Tang Dynasty, the direction of expansion has gradually shifted (for example, 193.14° during the Tang Dynasty and 167.02° during the Song and Yuan Dynasties); this reflects the gradual expansion of human activities to the east, and this trend returned to the north‒south direction again during the Qing Dynasty (177.82°).
(Source: Drawn by the author).
Clustering judgment: spatial distribution characteristics of ancient settlement heritage
According to the analysis results of global Moran’s I (Table 6), the distribution of ancient settlement heritage in the Nanxi River Basin shows significant spatial agglomeration. The global Moran’s I value of 0.331962 signifies positive spatial autocorrelation in the spatial distribution of settlements, suggesting nonrandom clustering of settlements in specific areas. This index is significantly higher than the expected value of −0.032258, which further supports the spatial agglomeration characteristics of the settlements. The z value is 3.130158, which is significantly higher than the critical value (1.96). The corresponding p value is 0.001747, which is less than 0.01, which means that at the 99% confidence level, the possibility of the settlement distribution being a random phenomenon can be ruled out. Combined with the spatial distribution type of Moran’s I (Fig. 6), the ancient settlements in the Nanxi River Basin show an obvious “agglomeration pattern”. This indicates that the settlements are mainly concentrated in a few specific areas rather than being dispersed or randomly distributed. The natural geographical environment of the basin is closely related to this agglomeration phenomenon. The distribution of settlements often occurs along the water system and in proximity to low-altitude areas. These areas have abundant water resources and fertile land, which are suitable for long-term human settlement and agricultural production.
(Source: Drawn by the author).
Accordingly, the ancient settlement heritage in the Nanxi River Basin shows significant spatial agglomeration and reflects the profound impact of natural geographical conditions and socioeconomic factors on the formation and distribution of settlements. The results of this analysis provide a solid quantitative basis for further exploration of the environmental, historical, and cultural heritage dynamics of settlement evolution.
Factors that influence the distribution of ancient settlement heritage
Natural distribution factors
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(1)
Elevation
Ancient settlements in the Nanxi River Basin primarily cluster in low-altitude areas, particularly within the range of 0–200 m above sea level (Fig. 7). In all historical periods, low-altitude regions have always been the main distribution areas of settlements. During the Qing Dynasty, the number of settlements distributed in this elevation range reached its highest level (71) and significantly exceeded that of other periods, indicating that the development level of low-altitude areas in the basin greatly increased during this period. The Song and Yuan Dynasties also had a high number of settlements (13), which shows the active development and utilization of the basin during this period. In the area between 200 and 500 m above sea level, the number of settlements is significantly smaller, and the settlement distribution appears only in a few periods. At high altitudes between 500 and 1000 m and above 1000 m, settlements are extremely rare or nonexistent. Accordingly, the suitability of the natural environment directly influences the elevation distribution of the settlements. An analysis of the distribution of settlements across various historical periods clearly reveals that the Nanxi River Basin settlements have consistently depended on natural resources in low-altitude areas (Table 7). During the early Neolithic Age and Eastern Han Dynasty, the majority of settlements (8 and 4 settlements, respectively) were located in areas with altitudes of 0–200 m. Over time, settlements gradually expanded to medium- and high-altitude areas of 200–500 m. During the Tang Dynasty and the Song and Yuan Dynasties, a small number of settlements began to appear in this range, indicating a moderate expansion of areas of human activity. However, the main distribution of settlements remained concentrated in low-altitude areas until the Qing Dynasty, suggesting that human activities still prioritized the resources in this terrain area.
Fig. 7: Elevation distribution of the settlements in different periods. 
(Source: Drawn by the author).
Table 7 Analysis of the differences in the elevation distributions of the settlements in different eras -
(2)
Slope
The main distribution characteristics of the ancient settlements in the Nanxi River Basin are in areas with relatively gentle slopes, especially in the slope range of 0–6° (Fig. 8). In all historical periods, the number of settlements in this range has been dominant. Among them, 42 settlements during the Qing Dynasty were located within this slope range, indicating that human settlement activities tended to choose flat or gentle slope areas, which are suitable for agricultural farming and daily life. This feature has persisted throughout various historical periods and reflects the strong attraction of gentle terrain to settlement site selection. Although the number of settlements decreases in the slope interval of 6–15°, many diverse distributions still exist. However, as the slope increases, the number of settlements decreases significantly, especially in slope areas of 25–35° and above 35°, where the number of settlements is minimal or nonexistent. The evolution of different periods reveals a relatively consistent trend in the slope distribution of settlements, which are primarily concentrated in areas with smaller slopes (Table 8). Early production methods and a high dependence on flat land led to the almost complete distribution of settlements from the Neolithic to the Eastern Han Dynasty within the slope range of 0–6° and 6–15°. Over time, settlements during the Song, Yuan, and Qing Dynasties had larger slope areas, especially areas with slopes ranging from 15–25°. This finding indicates that with technological progress and population growth, human activities gradually moved to areas with steeper slopes. However, the settlements remained concentrated in flat areas even during these periods of expansion, indicating that the terrain slope has always been a significant natural factor that influences settlement location. High-slope areas struggle to attract many settlement activities because of inconvenient transportation and insufficient cultivated land.
Fig. 8: Slope distribution of settlements in different periods. 
(Source: Drawn by the author).
Table 8 Analysis of the differences in the slope distributions of settlements in different eras -
(3)
Water system
The distance from the water system significantly influences the spatial distribution of ancient settlements in the Nanxi River Basin. The spatial layout of the ancient settlements depends on water resources, especially in agricultural societies, where water systems provide basic guarantees for survival and production. Specifically, during most historical periods, the settlements fall within the range of 0–400 m and 400–800 m from the water system (Fig. 9). Specifically, during the Qing Dynasty, 41 settlements were distributed within the 0–400 m range, demonstrating a strong reliance on the water system. There were also 14 settlements in the Song and Yuan Dynasties located within this distance range, which further indicates that settlements close to water sources have strong adaptability and sustainability. There are relatively few settlements within the range of 800–1200 m (Table 9). This shows that although settlement activities have expanded to areas farther from water sources, the land near the water system is still the most suitable area for human habitation and agricultural production. In areas farther from the water system, specifically, between 1200 and 1600 m and above 1600 m, settlements are very sparse or nonexistent.
Fig. 9: Distribution of the distances between settlements and river basins in different periods. 
(Source: Drawn by the author).
Table 9 Analysis of the differences in the distance between settlements and watersheds in different eras -
(4)
Comparison of the spatial distribution levels of traditional and nontraditional villages
We collected geographic data from 204 traditional and nontraditional villages in the Nanxi River Basin, including natural environmental data such as altitude, slope, and distance from the river. The results show that traditional villages are usually located in areas at lower altitudes, with gentler slopes, and close to water systems, which is closely related to their traditional water conservancy irrigation systems and economic activity patterns. Nontraditional villages are more common in areas with higher altitudes and steeper slopes. The natural conditions in these areas are relatively harsh and are often affected by factors such as modern development and road traffic. Through spatial density analysis, we found that the distribution of traditional villages is more concentrated around rivers, while nontraditional villages are more dispersed, reflecting changes in the development pattern of modern settlements. These differences indicate that natural environmental factors, especially topography and water systems, play important roles in the formation of traditional villages. Traditional villages often rely on the resource advantages of rivers and low-slope areas, whereas nontraditional villages are more affected by modernization, which results in their distribution in areas with poor environmental adaptability.
Social and cultural factors—the impact of intangible cultural heritage on settlements
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(1)
Spatial relationship between settlements and intangible cultural heritage
The spatial distribution of intangible cultural heritage closely correlates with the ancient settlements in the Nanxi River Basin. An analysis of the relationship between settlements and the dissemination radius of intangible cultural heritage in different historical periods can reveal the impact of the spatial layout of the settlements on cultural dissemination and inheritance. Figure 10 shows the spatial hierarchy of the distance between settlements and intangible cultural heritage across different periods. The concentration of most settlements occurs within a range of 1000–3000 m from intangible cultural heritage. During the Qing Dynasty in particular, the distribution of 51 settlements in this distance range demonstrated the strongest connection between settlements and intangible cultural heritage. There were also 13 settlements distributed in this interval during the Song and Yuan Dynasties, further supporting the significant connection between settlements and cultural heritage within this distance range. Although the number of settlements has decreased in areas 3000–5000 m away from intangible cultural heritage, a specific distribution still exists. Particularly in the Qing Dynasty, there were 12 settlements in this distance range. Compared with farther distances (such as more than 5000 m), this range can still maintain strong cultural communication and interaction. Notably, within the range of 0–1000 m from intangible cultural heritage, the number of settlements is small, but there is still a certain distribution, especially in the Neolithic Age and in the Song and Yuan Dynasties, where there were 4 and 5 settlements, respectively. This suggests that early settlements tended to be closer to cultural centers, and as history developed, communities gradually expanded outward.
Fig. 10: The relationship between settlements in different periods and the dissemination radius of intangible cultural heritage. 
(Source: Drawn by the author).
From a temporal perspective, the spatial relationship between settlements and intangible cultural heritage in the Nanxi River Basin shows a significant evolution trend. During the early Neolithic Age and Eastern Han Dynasty, a close range (0–3000 m) of intangible cultural heritage was the primary concentration of settlements. This close spatial connection reflects the high dependence between early settlements and cultural centers. Cultural heritage spread narrowly, and its scope of influence was confined to the periphery of the settlement. With the advent of the Tang, Song, and Yuan Dynasties, the number of settlements increased, and the spatial distribution began to expand farther. Especially during the Song, Yuan, and Qing Dynasties, the connection range between settlements and intangible cultural heritage expanded to areas of 3000–5000 m or even further, indicating the expansion of the cultural transmission radius and the enhancement of the settlement’s adaptability to cultural heritage (Table 10). However, despite the expansion of settlement distribution, the interaction between settlements and intangible cultural heritage remains relatively close, particularly with settlements within the range of 1000–3000 m, which still account for a significant proportion of settlements. Therefore, cultural communication and settlement development have formed a mutually dependent relationship. This relationship reflects not only the cultural radiation capacity of the cultural center to the surrounding settlements but also the settlements’ demand of and adaptability to intangible cultural heritage. The existence of cultural heritage enhances the settlements’ cultural identity and cohesion, while the settlements’ spatial layout also affects the dissemination path and scope of intangible cultural heritage.
Table 10 Differences in the intangible cultural heritage dissemination radius of settlements in different eras -
(2)
Analysis of the correlation between settlement space and intangible cultural heritage types
In addition, the researchers analyzed the correlation between settlements in multiple towns in the Nanxi River Basin and the distribution of intangible cultural heritage to uncover the impact of the spatial distribution of cultural heritage on the formation and development of traditional settlements. Table 11 shows a significant spatial correlation between the distribution of intangible cultural heritage in various towns and the number of settlements. In high-intensity related areas such as Xixia Township, Biaoshan Township, and Lingtou Township, the number of intangible cultural heritage sites and settlement sites is relatively high. There are 7 intangible cultural heritage sites and 24 settlement sites in Xixia Township, 6 intangible cultural heritage sites and 27 settlement sites in Biaoshan Township, and 5 intangible cultural heritage sites and 29 settlement sites in Lingtou Township. This demonstrates that there is a high degree of interaction between intangible cultural heritage sites and settlements in these areas. The concentrated distribution of cultural heritage provides these settlements with rich cultural resources and social cohesion. Moreover, the stability of settlements and cultural activities also promote the protection and inheritance of intangible cultural heritage. The results of the correlation characteristics between township culture and settlements indicate that different types of intangible cultural heritage play different roles in the distribution of settlements in various townships. Using Biaoshan Township as an example, the area is home to six intangible cultural heritage sites, primarily associated with traditional opera (such as Yongjia Kunqu Opera) and folk culture. The concentration of these cultural heritage sites promotes the agglomeration effect of settlements and forms a settlement structure with cultural activities at the core. In Luodong Township and Lingtou Township, although there are relatively few intangible cultural heritage sites (5 and 6, respectively), their settlement points still maintain a certain density (6 and 9, respectively). This finding indicates that the existence of intangible cultural heritage sites enhances the cultural identity of these settlements and that the inheritance of cultural heritage promotes the stability of the community and the maintenance of settlement space.
Table 11 Distribution of intangible cultural heritage sites and number of settlements in different townships and towns In addition, there is a differentiated distribution of cultural heritage types and settlement space; the distribution of different intangible cultural heritage types has different effects on the spatial layout of settlements (Fig. 11). Southern towns such as Nancheng Street and Biaoshan Township are characterized primarily by traditional opera (red) and folk culture (yellow). The spatial distribution of these heritage sites overlaps with the settlements and forms a cultural settlement network with opera and folk activities at the core. In northern towns such as Xixia Township and Lumen Township, the intangible cultural heritage of traditional medicine (blue) and traditional skills (green) occupies an important position, indicating that these settlements are highly dependent on this specific cultural heritage. This difference in cultural heritage types and settlement distributions reflects the different roles of different cultural forms in the social life of settlements. Opera and folk activities are often public cultural activities that provide a common cultural space for multiple settlements, while traditional skills and medicine are more concentrated in specific families or communities that form a settlement distribution pattern with specific skills at the core.
Fig. 11: Spatial classification of intangible cultural heritage in the Nanxi River Basin. 
(Source: Drawn by the author).
The spatial layout of intangible cultural heritage not only is a surface feature of settlement formation but also has a deeper impact on the cultural heritage, social structure and spatial development of a settlement. Particularly within the framework of a relatively closed environment, we observed that the interaction between settlements and cultural heritage in the Nanxi River Basin presents characteristics that differ from those of other open basins. Because of the closed nature of the geographical environment, the cultural heritage and social structure of the Nanxi River Basin are more introverted, and local culture has been relatively independently and persistently inherited. The closed nature of this environment limits the influence of external culture and promotes the cohesion and strengthening of the social structure within the settlement. In this closed environment, the inheritance of intangible cultural heritage, such as traditional skills, sacrificial clan activities and local festivals, has become the core element of a settlement’s cultural identity. The spatial concentration of cultural heritage has strengthened the social structure and cultural identity of settlements, thus affecting their spatial distribution. Specifically, settlements often form around water systems, and cultural heritage sites become part of the central area of a settlement to create a multicentered settlement structure. Furthermore, the relatively closed environment affects the spatial pattern and development of the settlement by affecting the inward spread of culture, the compactness of the social structure and the cultural identity of settlement members. This process shows how cultural heritage, as a driving force, not only affects the spatial layout of settlements but also shapes the social structure and cultural characteristics of settlements at a deeper level. Therefore, this study contends that the relatively closed environment plays a decisive role in the relationship between settlements and cultural heritage in the Nanxi River Basin and promotes the unique development trajectory of the settlements.
Figure 11 divides the area into high-intensity correlation areas (red) and strong correlation areas (yellow) to identify the spatial connection strength between intangible cultural heritage and traditional settlements. In Biaoshan Township and Lingtou Township, these areas show significantly high-intensity cultural heritage correlations, indicating that villages in these areas have strong symbiotic relationship with intangible cultural heritage. These high-intensity correlation areas demonstrate the strong preservation and inheritance of traditional village cultural functions. In addition, although Xixia Township is a strongly correlated area, it also shows intensive correlation in the distribution of traditional villages and intangible cultural heritage, which demonstrates that the influence of cultural heritage in this area is still large, although its correlation strength may be relatively low. From the perspective of overall spatial layout, the distributions of settlements and intangible cultural heritage are highly consistent, especially in high-intensity related areas, where settlements often become the center of cultural heritage activities. Therefore, the types and distribution of intangible cultural heritage reflect the diversity and inheritance of the lifestyles of local residents.
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(3)
Cultural heritage and regional characteristics of the settlements
There is a close interactive relationship between settlement formation and intangible cultural heritage in the Nanxi River Basin. Cultural heritage is an important part of local social life and profoundly affects the spatial layout and development trajectory of the settlements. The following are the four main findings. (1) There is a symbiotic relationship between settlement formation and cultural heritage. The Nanxi River Basin has a rich variety of intangible cultural heritage, including traditional opera, folk culture, traditional sports, cooking skills, and traditional medicine. A specific region has continuously inherited and developed these cultural forms (see Supplementary Table S1). Furthermore, the researchers found that the distribution of settlements and these different types of cultural heritage showed a high degree of consistency. This indicates that the residents of the settlements upheld a robust sense of cultural identity through their participation in opera activities. Cultural heritage provides not only a rich cultural life for residents but also an important means to maintain the social structure and cultural traditions of the settlement. Various types of intangible cultural heritage, especially folk culture and traditional opera, have formed deep connections with specific settlements. For example, Yongjia Kunqu Opera, as a national intangible cultural heritage, has a dissemination radius that mainly covers the surrounding traditional villages. Cultural inheritance strongly influences the formation and development of settlements, in addition to geographical location and resource conditions. These cultural activities play an important role in fostering social cohesion in the settlement space, gathering the social lives of residents, and enhancing community identity. (2) The cultural inheritance of settlements is influenced by their regional characteristics. The regional characteristics of settlements, such as the distribution of natural resources, water system conditions, and topography, have important impacts on the inheritance of intangible cultural heritage. For example, opera activities such as Yongjia Daoqing and Nanxi Gaoqiang are mostly concentrated around the water system of the Nanxi River. These areas have abundant natural resources, and they promote the flow and exchange of culture due to the convenience of the water system. Additionally, there is a significant spatial relationship between settlements, cooking skills, and traditional medicine. For example, settlements rich in agricultural resources predominantly spread traditional cooking skills, such as Yongjia wheat cakes, while the lifestyles of settlement residents and their respect for nature strongly influence traditional medicine. Resource dependence is closely related. The regional characteristics of the settlement intertwine with the inheritance of their cultural heritage and further deepens the uniqueness of the settlement. For example, the inheritance of Yongjia Kunqu Opera relies on the family inheritance mechanism within the village and continues and develops through cultural exchanges between settlements. This symbiotic relationship between culture and the settlement reflects the cultural embeddedness of settlement formation in the Nanxi River Basin (see Table S2). (3) The distribution of intangible cultural heritage is closely related to the regional characteristics of the settlements. High-intensity correlation areas, such as the villages of the Yongjia Kunqu Opera and Nanxi Gaoqiang, concentrate settlements in specific core cultural areas, which identifies their significant contribution to the formation and inheritance of cultural heritage. This strong connection between cultural heritage and settlement space not only reflects the formation mechanism of settlements but also illustrates the key role of cultural heritage in maintaining the spatial structure of settlements. (4) The relationship between settlement space and intangible cultural heritage is obviously hierarchical. The core distribution areas of cultural heritage are usually settlements with convenient transportation and abundant resources. These settlements are both the main places for cultural activities and key nodes for the intergenerational inheritance of cultural heritage. Using Yongjia Kunqu Opera as an example, the majority of its main settlements and cultural activity areas are situated in low-altitude regions with favorable water system conditions, which provide spatial support for cultural dissemination.
Discussion
Influencing mechanism of the spatiotemporal evolution of ancient settlements
The spatiotemporal evolution of settlements in the Nanxi River Basin is the result of the interaction between the natural environment and cultural heritage. The adaptive adjustment mechanism maintains both the spatial evolution of settlements and the continuity of cultural inheritance (Fig. 12). Similar to previous studies, natural conditions, such as altitude, slope, and distance to water systems, have a fundamental impact on the formation of settlements47,48. These natural environmental factors provided suitable agricultural production conditions and living resources for early settlements, resulting in settlements primarily concentrated in areas with low altitudes, gentle slopes, and near-water systems. This observation aligns with the views of most scholars who study the human settlement environment in the basin49,50. Furthermore, this study revealed that as society developed, settlements gradually spread to higher altitudes and areas farther from water sources, with natural conditions still playing a crucial role in determining the spatial distribution of settlements.
(Source: Drawn by the author).
The finding that intangible cultural heritage plays a key role in promoting the evolution of settlement space is consistent with previous related research51. On this basis, this study revealed that cultural heritage, such as opera, folk culture, traditional skills, and medicine, plays an important role in cultural identity and social cohesion and promotes the spatial agglomeration of settlements through their dissemination and inheritance. The distribution of cultural heritage often determines the interaction pattern between settlements, forming a symbiotic relationship between cultural dissemination and settlement development. This phenomenon was particularly significant during the Qing Dynasty in the Nanxi River Basin, which indicates that cultural factors had a long-term impact on the spatial pattern of the settlements. In addition, this study collected historical development data for the Nanxi River Basin through online local records and found that uncontrollable social factors, such as war (settlement fighting and dynasty change) and policies (examination reform), had sudden impacts on the spatial and temporal distributions of settlements. This led to the migration, diffusion, or disappearance of settlements in certain periods. However, the stability and durability of cultural heritage have enhanced the resilience of settlements to a certain extent. Through adaptive adjustment mechanisms, settlements can cope with environmental and social changes and maintain the continuity of their spatial structure. These findings explored more the social background and unexpected factors based on the relationship between most settlements and intangible cultural heritage52,53.
Cultural heritage inheritance of settlements in the Nanxi River Basin
Settlements in the Nanxi River Basin exhibit rich cultural connotations and strong regional characteristics through the dual inheritance of material cultural heritage (landscape) and intangible cultural heritage (humanities). The material cultural heritage of the settlements, such as traditional buildings, ancestral halls, and folk houses, has historical memory and social functions and further strengthens the cultural identity and cohesion of the community through the inheritance of intangible cultural heritage, such as operas, festivals, and handicrafts. Generation after generation has passed down the clan ritual system to contribute to the development and innovation of the settlements. The ancestral hall has become the core of clan activities and rituals, which maintains the social structure and cultural order within the settlements and allows the family culture to continue. Additionally, master-apprentice inheritance and family teachings have preserved traditional handicrafts; this highlights the ability of settlements to uphold traditional skills and production methods despite modernization challenges. The ecological environment also reflects this cultural inheritance, which extends beyond the preservation of social structure and skills. The settlements have achieved harmonious coexistence between humans and nature by respecting nature and using traditional farming methods to form a cultural ecological system in which culture and the environment continue together. The cultural heritage of the settlements in the Nanxi River Basin embodies a unique model of cultural heritage protection and continuation through the multidimensional inheritance of material, cultural, and ecological aspects.
Under the theoretical framework of intangible cultural heritage, studies have focused mainly on its static cultural value and have ignored its dynamic role in the formation and development of settlements54. This study proposes that intangible cultural heritage not only is a carrier of traditional culture but also plays a positive role in spatial evolution, social interaction, and economic exchange. By comparing and analyzing the settlement evolution process in the Nanxi River Basin and other basins, we found that the morphological evolution of intangible cultural heritage and settlements is highly interactive: they interact with each other and jointly shape a unique settlement landscape.
This study further explores the temporal relationship between intangible cultural heritage and settlement formation through a comparative analysis of the timeline. The formation of settlements in the Nanxi River Basin and the inheritance of intangible cultural heritage are highly synchronized. For example, clan culture and traditional skills in the basin began to be systematically inherited in the Ming and Qing Dynasties and became the core elements of settlement formation and development. In contrast, although the settlements in the Yangtze River Basin have a long history, because of its relatively open social environment, the inheritance of intangible cultural heritage is more influenced by foreign cultures, and the formation time is not completely synchronized with the evolution of settlements.
Ancient river basin settlements and spatial heritage in relatively closed environments
Unlike previous studies on regional river basin settlements, which focused on open river basins, plain river basins, and medium- and high-altitude river basins55,56,57,58,59, the Nanxi River Basin has received less attention as a closed river basin settlement. Therefore, the long-term synergy between the closeness to landscapes and cultural heritage became an unexpected discovery of this study. The Nanxi River Basin has an independent system (Fig. 13a). Its unique geographical closure provides important support for the protection of the space and cultural heritage of ancient settlements. Surrounded by mountains on three sides and facing water on one side, these geographical barriers effectively isolate against external intrusions such as war, cultural invasion, settlement migration, and ethnic colonization. The economic and trade exchanges in the lower reaches of the Nanxi River are prosperous, but the poor traffic conditions caused by the mountainous terrain in the middle reaches have delayed the urbanization process of the entire region, allowing the spatial pattern of the settlement to remain stable for a long period of time (Fig. 13b–d). This closed environment not only helps to preserve the spatial heritage of the settlement but also provides a protection mechanism for the inheritance of cultural heritage. Intangible cultural heritage, such as traditional opera, folk activities, and traditional skills, can be inherited and continued in a relatively independent environment while avoiding the impact of foreign culture, maintaining the purity and local characteristics of the culture, and thus forming independent cultural and dialectical circles.
(Source: Map a is sourced from the “Geographical Maps of Wenzhou Prefecture, Zhejiang” (Shunzhi period, early Qing Dynasty, AD 1661–1664), Map b is sourced from the “Yongjia County Gazetteer” (30th year of the Qianlong period, AD 1765), Map c is sourced from the “Yongjia County Gazetteer – Various Maps” (8th year of the Guangxu period, AD 1882), and Map d is sourced from the “Wenzhou Prefecture Road Map of Zhejiang” (date unknown)).
In addition, the closed environment prompted the settlement to form a self-sufficient “handicraft-agriculture” socioeconomic system. The residents of the settlement rely on internal resources and cultural heritage to form a stable community structure and cultural identity. This endogenous cultural development model enhances the resilience of the culture and allows the settlement to maintain relatively independent and continuous cultural and spatial characteristics in the face of external social changes. In general, the closed nature of the Nanxi River Basin protects the material spatial form of the settlement, ensures the long-term continuation and stability of the cultural heritage through the cultural self-regulatory mechanism and provides a valuable case for studying the protection of the cultural and spatial heritage of the Jiangnan waterside settlements.
The relatively closed environment of the Nanxi River Basin refers to both geographical isolation and a unique mode of cultural communication. In the Nanxi River Basin, the closed nature of the geographical environment promotes the self-enclosed characteristics of culture that allows intangible cultural heritage (for example, traditional skills, festivals, clan culture, etc.) to be continuously inherited in a relatively independent social structure. This closed environment has strengthened the cultural identity within the settlement, and the enhanced cultural identity has, in turn, affected the social structure and spatial distribution of the settlement. Cultural inheritance also plays a role in this relatively closed environment. Because of the relatively small infiltration of foreign culture, local culture can be preserved and passed down from generation to generation in a closed environment. This inheritance method further promotes social cohesion within the settlement so that the settlement has strong cultural commonality and social structure consistency.
In addition, the closed nature of the environment makes the spatial evolution of the settlement present a multicentered feature. Due to the strengthening of cultural identity, settlements often form multiple small centers around cultural heritage sites, which are interdependent and jointly promote the spatial distribution and social development of settlements. This unique spatial pattern and social structure demonstrate the profound impact of intangible cultural heritage on the spatial evolution of settlements.
Suggestions for the future protection of ancient villages
To better protect the cultural heritage of ancient villages in the Nanxi River Basin, future protection strategies need to comprehensively consider multiple dimensions, such as material heritage, intangible cultural heritage, the ecological environment, and community participation, to ensure the comprehensiveness and sustainability of cultural heritage. The following are specific protection suggestions.
(1) A hierarchical protection plan for ancient villages should be formulated. A hierarchical protection system should be established based on the historical and cultural value and preservation status of the village. Important historical villages, building complexes, and cultural heritage at the national, provincial, and local levels should be managed, and different protection plans should be formulated. The most stringent protection measures for villages with high historical and cultural value and relatively intact preservation, such as those with national cultural heritage, should be implemented, and large-scale reconstruction or demolition (which can choose to replace housing in neighboring villages) should be prohibited. For minor heritage sites with lower protection requirements, moderate repair and utilization can be carried out according to modernization needs.
(2) Digital protection and community participation should be combined. An effective cultural heritage protection strategy should not only protect physical heritage and sites but also promote the inheritance of intangible cultural heritage. Combining digital protection with community participation is a successful model for cultural heritage protection that can ensure the inheritance and sustainable development of cultural heritage in modern society. The specific implementation content is as follows. The first step is to establish a digital protection platform that is easily accessible to the public. By digitally recording and archiving traditional skills, historical documents, local festivals, clan sacrifices and other cultural heritage, a digital library with long-term storage and public access can be established. This helps ensure that cultural heritage is not easily affected by time and physical conditions and is preserved for a long period of time. The second step is content creation and data collection with community participation. Organizing local community members to conduct oral history and record local festivals and handicraft production processes ensures that the voice of the community occupies an important position in cultural heritage protection. This also helps the community identify with cultural heritage and increases their enthusiasm for cultural heritage protection. The third step is training and skills development. Local residents and craftsmen should be provided with training on the use of digital tools for heritage preservation so that they can directly participate in digital protection work, thereby enhancing the sense of participation and responsibility of community members in cultural heritage protection. Successful international heritage protection cases have provided many valuable references. For example, the protection of cultural heritage in Tuscany, Italy has achieved a balance between the inheritance of intangible cultural heritage and tourism development through cooperation between the community and local government. In this region, the protection of cultural heritage includes the restoration of buildings and the protection of local folklore and traditional handicrafts, and it combines the concept of the sustainable development of cultural tourism.
(3) Cultural tourism routes should be designed, and overcommercialization should be prevented. Cultural tourism not only is an effective means of protecting cultural heritage but also provides a new area of growth for the local economy. However, overcommercialization must be avoided to prevent the uniqueness of cultural heritage from being destroyed. The specific implementation steps are as follows. (a) Sustainable tourism routes should be designed. Tourism routes should be planned based on the value and fragility of cultural heritage to avoid the overdevelopment of sensitive areas. By limiting the number of tourists and adjusting the number of visits during peak tourist seasons, the flow of tourists can be kept within a certain range to avoid damage to heritage sites. At present, there is room for the development of the settlements in the upper reaches of the Nanxi River and the western area of the middle reaches of the river basin, but during development, the protection standards for the settlement heritage and the degree of development of different nature reserves should be reconsidered. (b) Local residents can design and promote cultural experience projects with local characteristics, such as the traditional dyeing and weaving handicraft production in Cangpo Village and folk art exhibitions in Yantou Village and Fenglin Ancient Town, so that tourists are both observers of and participants in cultural heritage. The successful balance between cultural tourism and heritage protection achieved in Cinque Terre National Park in Italy serves as a valuable reference. By limiting the number of tourists and emphasizing environmental protection and cultural respect, the Cinque Terre has avoided overcommercialization and preserved its unique fishing village culture. (c) The third step is to regulate commercial development. Commercial enterprises related to cultural tourism should be regulated to prevent large-scale commercial development from eroding the core values of cultural heritage. Particularly hotels, restaurants and souvenir shops must follow the regulations on cultural heritage protection and avoid overdevelopment and low-quality commercial activities.
(4) The village environment and ecological protection should be improved. The ancient villages in the Nanxi River Basin are closely connected to the natural environment. Therefore, when safeguarding these villages, we must prioritize the preservation of the surrounding ecological environment. Strictly controlling construction development around villages is necessary to prevent the destruction of the traditional landscape. Moreover, we should strengthen the protection of the water systems, vegetation, and farmland and give special attention to the management of water resources to maintain the symbiotic relationship between the village and the water system. By developing organic agriculture and ecological cultivation, we can maintain the village’s traditional farming culture and prevent modern agriculture from harming the ecological environment and traditional landscape.
(5) A landscape gene map and digital management should be established. We constructed a landscape gene map of the Nanxi River Basin through field investigations and the collection of spatial and cultural data from 204 settlements, with the aim of preserving the settlement features, architectural space, and regional cultural customs. Drones, 3D scanning, GIS, and other technical tools enabled us to accurately record and monitor village buildings and spatial layouts and establish digital archives of ancient villages for long-term maintenance and management. Simultaneously, we can utilize virtual reality (VR) technology to create digital display content, which would enable a wider audience to comprehend and engage with the cultural heritage of ancient villages via digital platforms, thereby fostering cultural dissemination and raising awareness of preservation.
Conclusion
The researchers in this study closely examined how the ancient settlement heritage in the Nanxi River Basin changed over time and space. They found that the changes in the spatial patterns of the Jiangnan waterside settlements during different historical periods were affected by both natural and cultural factors. The main findings of this study are as follows. (1) The spatiotemporal evolution of the settlements reflects the unique development model of the Nanxi River Basin in the interaction between humans and nature. During the Ming and Qing Dynasties, clans, culture, and the economy drove the expansion of early settlements, which relied on water systems and flat terrain to form a multicenter distribution. During the Neolithic Age to the Qing Dynasty, the distribution of settlements in the Nanxi River Basin transitioned from a single-point distribution to multipoint aggregation and divergence, reaching their peak development during this period. The overall center of gravity shift trend of settlements shifted from south to north and east, with the fastest movement occurring during the Tang-Five Dynasties and the Song and Yuan Dynasties. During the Ming Dynasty, the settlements started moving south again. In general, the distribution of ancient settlements exhibited clustering. (2) The natural environment and intangible cultural heritage factors jointly influenced the spatiotemporal evolution of the settlements. The analysis of the impact of the natural environment reveals that the settlements primarily cluster in low-altitude and flat areas, which highlights the significance of water sources and terrain in their formation. Areas close to water sources are more likely to become the first choice for settlement site selection, while settlements are less likely to appear in areas with larger slopes. Over time, the settlements gradually expanded to areas with higher slopes farther away from water sources, but the decisive role of water systems in settlement site selection remains unchanged. The spatial relationship between the settlements and intangible cultural heritage shows that the existence of cultural heritage not only affects the social structure and cultural heritage of settlements but also promotes the cohesion and adaptability of settlement space. In particular, intangible cultural heritage, such as opera and folk culture, has a significant effect on the formation and stability of settlements, and the core areas of cultural communication highly overlap with the spatial distribution of settlements. (3) This study, through an in-depth analysis of the spatial relationship between settlements and intangible cultural heritage in the Nanxi River Basin, reveals the unique role of a relatively closed environment in cultural heritage protection. Cultural heritage affects the spatial layout of settlements and profoundly impacts the cultural identity, social structure and cultural inheritance of settlements. This study provides a new theoretical perspective for understanding the role of intangible cultural heritage in settlement evolution and provides valuable experience and a theoretical basis for heritage protection and spatial planning in similar areas in the future.
However, this study also has shortcomings. For example, (1) there are limitations of ancient settlement data acquisition, for example, historical data on some settlements are relatively scarce, and there is especially a lack of comprehensive literature and field survey data on early settlements, resulting in an inadequate analysis of the formation and evolution of settlements in some periods. This may affect the comprehensive understanding of the distribution of settlement heritage sites and the laws of spatiotemporal evolution in the entire Nanxi River Basin. (2) The research on intangible cultural heritage lacks depth. Although this article highlights the importance of intangible cultural heritage in settlement formation, the study of its specific inheritance mechanism and spatial impact is relatively superficial, and it fails to explore the complex interactive relationship between cultural inheritance and settlement spatial layout from an objective and quantitative perspective. (3) The spatial data analysis has certain limitations. This study uses a GIS analysis to reveal the basic laws of settlement distribution, but the spatial analysis method lacks explanatory power to detail socioeconomic interactions and cultural inheritance paths between specific settlements, and it does not account for multidimensional factors such as settlement dynamic development and cultural adaptability. Future research is likely to explore this further.
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