Mapping the spatiotemporal evolution and driving mechanisms of intangible cultural heritage in Southeast Coastal China

Abstract

Southeast Coastal China boasts abundant marine Intangible Cultural Heritage (ICH), yet quantitative assessments of its long-term driving mechanisms remain insufficient. This study analyzed 2372 ICH items(refined from 2384 records) via spatial models and Geodetector. Results indicate: (1) Spatiotemporally, provincial ICH centers of gravity show a fluctuating southward migration trend, with an average distance of 218 km. (2) Spatially, all categories of ICH displayed significant clustering (Nearest Neighbor Index: 0.29–0.68), presented to diverse dual-, triple-, and multi-core agglomeration patterns. (3) Mechanistically, human factors (q = 0.34) slightly outweigh natural factors (q = 0.32). Furthermore, interaction results exhibit bivariate or nonlinear enhancement, with the combined effect of the factors water system and GDP being the strongest. (q = 0.90). Theoretically, these findings reveal the underlying evolutionary patterns and multi-dimensional driving mechanisms of marine ICH. Practically, they provide a robust scientific basis for cross-regional collaborative governance and conservation strategies.

Introduction

ICH refers to various practices, performances, expressions, knowledge, and skills that are recognized by communities as part of their cultural heritage, along with the associated instruments, objects, artifacts, and cultural spaces^1,2,3_. ICH is a crucial manifestation of national identity and cultural continuity⁴, and its spatiotemporal evolution is a classic research topic in the field of cultural geography. It encompasses diverse cultural expressions, from traditional handicrafts and Folk customs to Traditional arts, and is a concentrated embodiment of human living heritage^5,6. However, under the dual pressures of globalization and rapid modernization, as well as profound social transformations, ICH is facing increasingly severe risks of intergenerational discontinuity and cultural homogenization^7,8. As a typical marine cultural-geographical unit with rich maritime ICH, the southeastern coastal area of China (covering Guangdong, Guangxi, and Fujian provinces) is a core area for the implementation of national cultural strategies such as the “21st-Century Maritime Silk Road” cultural corridor and the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) cultural development plan^9,10. Against this backdrop, clarifying the spatiotemporal evolution patterns and multi-dimensional driving mechanisms of ICH in this region is of great significance. It not only has important practical guiding significance for cross-regional collaborative protection of marine ICH, but also fills the gap in the research on the spatial differentiation patterns of ICH in typical marine cultural regions.

Research on ICH has evolved through three stages: traditional qualitative studies, mathematical modelling, and interdisciplinary studies. In early research, scholars have explored the connotations, value systems, and theoretical frameworks of ICH from disciplinary perspectives, including anthropology, folklore studies, and the arts^11,12. With the evolution of ICH research, scholars began to adopt quantitative methods and models, such as statistical analysis, correlation and regression techniques, and cluster analysis, to examine ICH data more systematically^13,14,15,16. With the introduction of digital technologies^17,18,19,20 and spatial analysis, ICH research has increasingly transcended single-discipline boundaries^19,20,21. This interdisciplinary approach enables scholars to investigate the spatial distribution patterns, evolutionary trajectories, and underlying driving factors of ICH across expanded geographical scales and longer temporal dimensions.

However, extant studies on ICH have predominantly been conducted at either national or single-province or city scales, leaving a notable gap in region-specific, cross-administrative investigations^22,23,24,25. Furthermore, in terms of research content, existing studies primarily focus on the classification system, inheritance and development paths, and protective strategies of ICH^26,27. The systematic research on the long-term spatiotemporal evolution and spatial patterns of ICH is still insufficient. There is also relatively scant research that systematically unravels the driving mechanisms behind its spatiotemporal distribution through the lens of multi-factor interactions.

Research on ICH methods spans two main strands: spatial evolution and spatial differentiation mechanisms. The research methods of ICH primarily include spatial analysis and the examination of spatial differentiation mechanisms. For spatial analysis, existing studies frequently use methods such as Standard Deviational Ellipse (SDE) ^28,29, imbalance index, and geographic concentration index to characterize the spatial clustering and dispersion patterns of ICH resources^30,31,32. For spatial differentiation mechanisms, commonly used methods include spatial Durbin models, Geographically Weighted Regression(GWR), or Structural Equation Modeling(SEM)^33,34,35,36. These methods can quantitatively identify the correlation between the distribution of ICH and natural, social, and economic factors, and capture the characteristics of local spatial heterogeneity. However, these models are often based on linear assumptions, which fail to adequately reflect nonlinear relationships and interaction effects between variables. They are also susceptible to factors such as spatial autocorrelation, which limits their causal explanatory power and constrains their ability to reveal the interactive mechanisms among multiple factors. To address these limitations, this study introduces the Geodetector. This model does not rely on linear assumptions and can simultaneously identify the explanatory power of both single-factor and multi-factor interactions on spatial differentiation, thus effectively overcoming many limitations of traditional models. Geodetector has recently been applied to ICH research in several regions, including the Jiang-Zhe-Hu area³⁷, the Yangtze River Delta³⁸, Shanxi Province³⁹, and at the national scale for both tangible and intangible heritage⁴⁰. These studies consistently find that Geodetector can reveal the driving factors and synergistic effects behind cultural heritage. However, few studies have applied Geodetector to the systematic analysis of ICH in marine cultural regions, while the complex interactions between water systems, ethnic diversity, and coastal trade in these regions require this nonlinear, interaction-sensitive approach. Based on this framework, this study analyzes the influence of natural and human factors on the spatial distribution of ICH in southeastern coastal China, with particular attention to the enhancing or weakening effects of multi-factor interactions.

In terms of regional selection for ICH research, existing studies still exhibit notable limitations in the geographic location and scale of their study areas. Some studies use the national scale as the primary unit of analysis^40,41,42, which can only reveal the overall distribution patterns of ICH. However, these studies suffer from low spatial resolution and are limited in capturing intra-regional cultural differences and the finer details of spatiotemporal evolution. Although studies conducted at the provincial or municipal scale offer higher spatial resolution^23,39,43, they are often constrained by administrative boundaries, ignoring historical continuity, leading to the artificial fragmentation of cultural landscapes. Some studies selected a single inland or coastal region as the study area^10,37,44, which lacks comparative perspectives across diverse geographical environments. This limitation constrains the in-depth examination of the synergistic effects between natural and human factors. To address these deficiencies, this study selects a distinctive region—the three southeastern coastal provinces of Fujian, Guangdong, and Guangxi—as the research area, thereby compensating for the limitations of existing studies. This region has an optimal meso-scale. It captures the overall spatiotemporal patterns of ICH in southern coastal China, while also revealing internal regional differences and local clustering phenomena. From a physiological point of view, the region contains diverse landform types—including mountains, plains, and coastal areas—and features a rich vertical ecological gradient, making it an ideal area for analyzing the influence of physical factors on the distribution of ICH⁴⁵. From a socio-cultural perspective, the three provinces have long-standing connections in language, ethnicity, and trade⁴⁶. Repeated southward population migrations and sustained maritime exchange have shaped a complex dialect landscape⁴⁷. Consequently, the region hosts comprehensive ICH categories with strong inter-provincial linkages. together with clear maritime cultural characteristics⁴⁸. Overall, the region provides a typical and advantageous case area for examining the spatiotemporal distribution and driving mechanisms of ICH in coastal areas.

In light of these research gaps, this study systematically examines the spatiotemporal distribution patterns and multidimensional driving mechanisms of ICH in southeastern coastal China. The main contributions and innovations of this study are as follows:

• 1. Establishes an integrated cross-provincial framework for Guangdong, Guangxi, and Fujian, addressing the lack of holistic research in this region.

• 2. Identifies historical development stages and characterizes the spatiotemporal evolution of ICH using standard deviational ellipses and nearest-neighbor indices. Classifies core distribution patterns and analyzes the macro-spatial patterns of different ICH categories.

• 3. Applies the geographical detector to construct a multidimensional factor system—including linguistic zones, transportation, water systems, and climate—and quantifies the dominant factors and their interactions driving the spatial patterns of ICH, ultimately proposing differentiated strategies for ICH conservation.

Methods

Study area

This study selects Guangdong, Guangxi, and Fujian in Southeast Coastal China as the study area(Fig. 1), situated between 20 °13′–28 °31′ N and 104 °27′–120 °43′ E. Covering a total area of approximately 537,000 km². The area exhibits significant physical geographical heterogeneity, with an elevation difference of nearly 3000 meters. Spanning from subtropical to tropical climate zones, the region is characterized by an average annual temperature ranging from 15 to 23 °C and annual precipitation between 1200 and 2000 mm. With a coastline exceeding 5900 km⁴⁹, accounting for 40% of China’s total, the area exhibits significant environmental gradients, providing a favorable environment for the development of ICH. Since the Qin and Han dynasties, sustained southward migration and maritime exchange have produced a complex dialect mosaic and diverse ethnocultural groups⁵⁰. Against this backdrop, the region’s rich ICH portfolio offers a representative case for analyzing spatiotemporal patterns and their driving mechanisms.

Fig. 1: Study area. The background color gradient represents the Digital Elevation Model (DEM), indicating elevation values ranging from -162 to 2155.

Different categories of Intangible Cultural Heritage (ICH) are represented by distinct colored shapes: green triangles for Traditional medicine, teal pentagons for Traditional drama, red circles for Traditional handicraft, blue squares for Traditional art, purple hexagons for Traditional dance, grey circles with a central dot for Traditional music, light yellow circles for Traditional sports, recreation and acrobatics, yellow circles for Quyi, pink circles for Folk custom, and light blue circles for Folk literature. This map is based on the standard map with approval number GS(2022)1873.

Data source and preprocessing

The data on ICH originates from the official website of the Intangible Cultural Heritage Protection Center for Fujian, Guangdong, and Guangxi Provinces (Table 1). It encompasses five batches of national and seven batches of provincial ICH items (with Guangdong and Guangxi also including an eighth batch), totaling 2384 items. This includes 380 national ICH items, with 145 from Fujian Province, 165 from Guangdong Province, and 70 from Guangxi Province. Additionally, there are 2004 provincial ICH items, comprising 769 from Fujian Province, 740 from Guangdong Province, and 876 from Guangxi. After preprocessing, the data totals 2372 items. The principles of data preprocessing are as follows: (1) For certain ICH items of varying levels, the highest level is used for calculation. (2) The same ICH distributed in different regions or in different protection units is divided according to the protection unit. (3) According to the National ICH Representative List, the types of ICH are divided into “ten categories” of folk literature, folk custom, traditional music, traditional dance, traditional drama, Quyi, traditional sports, recreation and acrobatics, traditional art, and traditional handicraft.

Table 1 Research data sources

Research framework

To systematically reveal the spatiotemporal dynamics and driving mechanisms of ICH in Southeast Coastal China, and to propose sustainable protection strategies, this study constructs a comprehensive analytical framework (Fig. 2). First, regarding temporal evolution, we divided ICH development into seven historical periods to identify its developmental stages. Utilizing the Standard Deviation Ellipse and the gravity model, we visualized the directional migration trajectory of ICH at both the holistic regional and provincial scales. Subsequently, regarding spatial distribution characteristics, we employed the Nearest Neighbor Index and Kernel Density Estimation to quantify the aggregation degree of different ICH categories and identified three core spatial patterns of ICH distribution. Finally, regarding driving mechanisms, we applied the Geodetector to quantify the explanatory power of individual factors and uncover the complex non-linear relationships between them.

Fig. 2: Research framework.

The framework is divided into three main analytical modules. The top module (green) illustrates the temporal distribution characteristics of ICH across seven historical periods, using Standard Deviational Ellipse (SDE) analysis to track the center of gravity and movement paths at both holistic and provincial levels. The middle module (blue) evaluates the spatial distribution characteristics, employing Nearest Neighbor Index (NNI) and Kernel Density Estimation (KDE) to assess aggregation degrees and density cores. The bottom module (red) establishes the system of driving factors for ICH distribution, utilizing Geodetector for single-factor detection and interactive detection of both natural and human factors. In the natural factors, DEM refers to the Digital Elevation Model, and NDVI refers to the Normalized Difference Vegetation Index.

Standard deviation ellipse

The SDE²⁸ is a global, pattern-level statistic that summarizes a spatial point set’s dominant orientation, dispersion, and anisotropy. It was widely used to quantify the principal directional trends of geographic features and track their spatiotemporal shifts. The calculation formula is expressed as follows:

$${SD}{E}_{x}=\sqrt{\frac{{\sum }_{i=1}^{n}{\left({x}_{i}-\bar{X}\right)}^{2}}{n}},{SD}{E}_{y}=\sqrt{\frac{{\sum }_{i=1}^{n}{\left({y}_{i}-\bar{Y}\right)}^{2}}{n}}$$

(1)

Where, $({x}_{i},{y}_{i})$ are the spatial coordinates of feature $i$, $\bar{X}$ and $\bar{Y}$ represent the arithmetic mean center of feature $i$, and $n$ is the total number of features^28,51.

This study applies Scott’s (1992) two-dimensional rule of thumb to estimate the theoretically optimal bandwidth for each ICH category, represented as follows.

$$h=\sqrt{\left\{{\sigma }_{x}^{2}+{\sigma }_{y}^{2}\right\}}\cdot {n}^{-\frac{1}{6}}$$

(2)

where h is the optimal bandwidth, σx and σy are the standard deviations of the point coordinates in the east–west and north–south directions, respectively, n is the sample size⁵².

The gravity model

The gravity model is a method for quantifying the spatial change patterns of factors⁵³. It investigates the spatiotemporal evolution patterns of factors by studying the geometric center-of-gravity position of the standard deviation ellipse of each factor within a research area and its trajectory over time. The formula for calculating the center of gravity is:

$$\bar{x}=\frac{{\sum }_{i}^{n}{m}_{i}{x}_{i}}{{\sum }_{i}^{n}{m}_{i}},\bar{y}=\frac{{\sum }_{i}^{n}{m}_{i}{y}_{i}}{{\sum }_{i}^{n}{m}_{i}}$$

(3)

Where ($\bar{x},\bar{y}$) represents the coordinates of the centroid of the region, $({x}_{i},{y}_{i})$ is the spatial coordinate of the $i$-th element, and ${m}_{i}$ is the weight of the $i$-th element⁵³.

Nearest Neighbor Index

The Nearest Neighbor Index (NNI) is a statistical metric that assesses the clustering or dispersion of spatial point patterns⁵⁴. Its basic idea is to compare the average nearest neighbor distance of the observed samples with the theoretical expected distance under a Complete Spatial Randomness (CSR) to determine whether the points are clustered, random, or uniformly distributed in space. Generally, ${NNI}$ ≤ 0.8 is considered an aggregated distribution, 0.8 < ${NNI}$ < 1.2 is considered a random distribution, and 1.2 ≤ ${NNI}$ is considered a uniform distribution. The formula for calculating the nearest neighbor is:

$${NNI}=\frac{{\sum }_{i=1}^{N}\frac{{\min (d}_{{ij}})}{N}}{0.5\sqrt{\left(\frac{A}{N}\right)}}$$

(4)

Where ${\min (d}_{{ij}})$ represents the distance from the $i$-th sample point to its nearest neighbor sample point, $N$ represents the total number of sample points, and $A$ represents the total area of the study area⁵⁴.

Kernel density estimation

Kernel Density Estimation (KDE) is a nonparametric statistical method used to estimate the density distribution characteristics of spatial point features^55,56. Its core principle is to reveal spatial clustering characteristics by calculating the local density changes of sample points within the study area, and to visually display the hot spots and cold spots in the spatial distribution.

$${\hat{f}}_{h}\left(x\right)=\frac{1}{{nh}}\mathop{\sum }\limits_{i=1}^{n}K\left(\frac{x-{x}_{i}}{h}\right)$$

(5)

Where ${\hat{f}}_{h}\left(x\right)$ is the estimated probability density function at $x$, $n$ is the sample size, $K(x)$ is the kernel function, and $h$ is the bandwidth^55,56.

Geodetector

Geodetector is a statistical method for analyzing spatial stratified heterogeneity and its underlying driving factors. Its core idea is that if an independent variable has a significant impact on the dependent variable, then their spatial distributions should exhibit similarity. This study employs the factor detector and interaction detector^57,58.

Factor detector: detects the spatial heterogeneity of the dependent variable $Y$ and quantifies the explanatory power of the independent variable $X$ on $Y$, expressed as a $q$ value.

$$q=1-\frac{{\sum }_{h=1}^{L}{N}_{h}{\sigma }_{h}^{2}}{{N\sigma }^{2}}=1-\frac{{SSW}}{{SST}}$$

(6)

$${SSW}={\sum }_{h=1}^{L}{N}_{h}{\sigma }_{h}^{2},{STT}={N\sigma }^{2}$$

(7)

Where ${SSW}$ is the sum of variances within a stratum, and ${SST}$ is the total variance of the entire region. $L$ represents the stratification of the dependent variable or factor, ${N}_{h}$ and $N$ are the number of units in stratum $h$ and the entire region, respectively, and ${\sigma }_{h}^{2}$ and ${\sigma }^{2}$ are the variances of the dependent variable $Y$ values in stratum $h$ and the entire region, respectively. $q$ takes values of [0,1]. The larger the $q$, the more obvious the spatial heterogeneity, and the stronger the explanatory power of the influencing factor on the spatial distribution of ICH^57,59.

Interaction detector: Evaluates whether the combined effect of two variables ${x}_{i}$ and ${x}_{j}$ on $Y$ is enhanced or weakened. Interaction types include^58,60 :

Nonlinear Enhancement:

$$q\left({x}_{i}\cap {x}_{j}\right) > q\left({x}_{i}\right)+q\left({x}_{j}\right)$$

(8)

Two-factor enhancement:

$$q\left({x}_{i}\cap {x}_{j}\right) > {\rm{Max}}\left(q\left({x}_{i}\right),q\left({x}_{j}\right)\right)$$

(9)

Single-factor nonlinearity attenuation

$${\rm{Max}}\left(q\left({x}_{i}\right),q\left({x}_{j}\right)\right) > q\left({x}_{i}\cap {x}_{j}\right) > {\rm{Min}}\left(q\left({x}_{i}\right),q\left({x}_{j}\right)\right)$$

(10)

The selection of Geodetector in this study is primarily driven by its significant advantages in addressing the spatial complexity and nonlinear characteristics of driving factors behind cultural heritage distribution. Compared to Geographically Weighted Regression (GWR), Geodetector provides a more robust analytical framework that effectively captures nonlinear relationships without the constraints of linear assumptions or the risks of multicollinearity. Unlike Structural Equation Modeling (SEM), Geodetector is a strictly data-driven approach that quantifies driving forces through the q-statistic without depending on predefined causal pathways or structural assumptions. These attributes enable Geodetector to more objectively evaluate the influence of individual factors and precisely identify the synergistic interaction effects between them.

Results

The temporal evolution trend of ICH across dynasties

The profound historical continuity from the Pre-Qin period onward has underpinned the accumulation of a rich and diverse spectrum of ICH in Fujian, Guangdong, and Guangxi. Using dynastic succession as the temporal framework, this study traces the evolutionary trajectory of ICH across seven historical periods(Table 2): Pre and Qin, Han and Jin, Sui and Tang, Song and Yuan, Ming, Qing, and the Modern era. By synthesizing the characteristic features of each period, the timeline is consolidated into three developmental stages: Origin and Development (Pre-Qin to Han and Jin), Prosperity (Sui and Tang to Song and Yuan), and Maturity (Ming and Qing to the Modern era). Within this periodization framework, dates of origin were explicitly identified for 2,372 ICH items in the study area.

Table 2 Temporal distribution characteristics

The Pre-Qin and Han-Jin periods mark the origin and early development of ICH. During this stage, Traditional Craftsmanship and Folklore were the predominant categories. The ICH transmission was constrained by the monopoly of handicrafts by social classes and families. The flourishing of agriculture and handicrafts during the Qin Dynasty spurred the comprehensive development of textiles, bronze ware, lacquerware, ceramics, jade ware, and other handicraft categories. The establishment of specialized institutions and hierarchical management during the Western Han Dynasty further promoted the continuation of handicrafts and folk culture. However, it was still limited by the strict feudal hierarchy and closed family transmission models; for example, jade ware was exclusively for the royal family, and family medical skills were not passed on to outsiders. Early ICH struggled to gain widespread popularity among the general public, and due to its long history, some ICH items gradually disappeared or were lost.

The prosperity stage encompasses the Sui and Tang Dynasty and Song and Yuan Dynasty periods, with the Sui and Tang Dynasty era marking the first peak in the developmental trajectory of ICH. This stage witnessed a significant expansion in the number of ICH items, reaching a total of 982, thereby demonstrating comprehensive development across cultural, artistic, and technical domains. Specifically, the Sui and Tang period accounted for 424 items, with Traditional handicraft (142 items) and Folk customs (94 items) being the most prevalent categories, reflecting the flourishing state of handicraft industries and folk traditions during this era. Subsequently, the total number of ICH items in the Song and Yuan period further increased to 558, characterized by a notable proliferation of Folk customs. During this stage, thriving trade in the South China Sea, with Quanzhou emerging as a global maritime commercial center, significantly facilitated cultural exchange and productivity growth, thereby propelling the prosperity of Traditional handicrafts. Concurrently, massive population migration and the southward shift of the national economic center transformed the region comprising Guangdong, Guangxi, and Fujian into a vital repository of Chinese civilization, leading to the flourishing of Folk customs. Furthermore, advancements in papermaking and printing technologies, combined with economic affluence, stimulated the development of Folk literature, Traditional drama, and Traditional music. Collectively, the cultural vibrancy of this era bequeathed a rich legacy of ICH to subsequent generations.

The Maturity stage, spanning the Ming, Qing, and Modern eras, accounts for the origin of 565, 503 and 42 documented ICH items, respectively. Notably, the Ming Dynasty represents the second zenith in the evolution of ICH. During the Ming and Qing periods, sustained political consolidation fostered prosperity in agriculture and handicraft production. This growth was further reinforced by the extensive cultivation of cotton and the introduction of high-yield crops, which together substantially elevated overall productivity. This economic foundation propelled the advancement of porcelain manufacturing and textile weaving, resulting in the emergence of a large number of items classified as Traditional handicrafts. Culturally and ideologically, this era exhibited a trend toward diversification, characterized by intensified ethnic exchange and integration. The rise of the School of Mind (Xin Xue) and the artistic advocacy of ‘expressing one’s genuine feelings’ catalyzed an unprecedented flourishing of vernacular literature, including novels and dramas. This cultural climate gave rise to performing arts heritage such as Min Opera and Yue Opera, categorized under Traditional drama, while simultaneously accelerating the diversification of Traditional Music and Traditional dance. In stark contrast, the Modern era was marked by frequent warfare and social turbulence, leading to a precipitous decline in the number of newly originated ICH items, with Fujian and the Guangdong and Guangxi region bearing the brunt of these disruptions.”

Overall, the temporal evolution process of the quantity of ICH originating in China’s southeastern coastal regions presents a trend of fluctuating ascent followed by a decline. The Pre-Qin to Jin periods were the period of origin and development, where ICH categories were limited and mainly concentrated in Traditional handicrafts and Folk customs. The Sui-Tang to Song-Yuan periods were the prosperity stage, marking the first peak of ICH origination. The Ming and Qing periods entered the maturity period, reaching the second peak of ICH origination. However, in the modern era, internal troubles and foreign aggression led to a sharp decrease in the quantity of ICH origination and hindered transmission. The evolution of ICH is closely connected with economic development, population migration, cultural exchange, and social stability, presenting obvious phasic characteristics and regional differences. Under long-term historical and cultural accumulation, ICH culture has been continuously accumulated and developed, presenting characteristics of vast quantity and diverse types.

Temporal evolution trend of the overall region

The SDE parameters (Table 3) and the spatial shifts of the gravity center (Fig. 3a) were analyzed for ICH in three southern coastal provinces across multiple scales. A holistic analysis reveals that the variation characteristic of the spatial distribution of ICH in the three southern provinces exhibits a northeast-southwest directional fluctuation in its center of gravity, and its spatial distribution generally shifts eastward.

Fig. 3: Diagram of the ICH center of gravity and ellipse distribution across different historical periods.

a Overall elliptical positions and centers of gravity in different periods. The grey dots represent individual ICH points. The colored triangles represent the center of gravity, and the colored outlines represent the standard deviational ellipses. Different colors correspond to specific historical periods: red for Pre-Qin, salmon for Han and Jin, yellow for Sui and Tang, green for Song and Yuan, blue for Ming, pink for Qing, and purple for Modern times. b An enlarged view of (a) detailing the movement path of the ICH centers of gravity, indicated by the corresponding colored triangles connected by black arrows. c An enlarged view of the eastern section of a detailing the distribution range and shifts of the ellipses across different periods.

Table 3 ICH Ellipse Data at different times

As civilization expanded toward the coast, the center of gravity of ICH showed a pronounced eastward shift from the Pre‑Qin through the Sui and Tang periods (Fig. 3b). Specifically, during the Pre-Qin period, the distribution centroid was situated in Huaiji County in northwestern Guangdong, the westernmost position across the entire historical timeline. At this stage, ICH development was predominantly concentrated in inland regions, with Guangxi containing the largest number of documented items (91), compared to 32 in Guangdong and 36 in Fujian. Subsequently, during the Han, Jin, Sui, and Tang periods, the centroid continued to shift eastward, marking a new phase in regional cultural development. By the Sui and Tang period, the centroid had reached Lianping County in Guangdong, the easternmost locus among the seven historical centroids. This shift was driven by the sustained southward migration of Han people from the Central Plains and intensified overseas trade and cultural exchange, which significantly boosted ICH proliferation in eastern Guangdong and Fujian, particularly along coastal zones. Notably, Fujian originated 189 ICH items during the Sui and Tang period, marking the historical peak of ICH formation for the province.

In the second phase of centroid migration (Song-Yuan to Qing dynasties), a pivotal inflection point occurred, with the trajectory turning distinctly toward the southwest. During the Song and Yuan periods, the southward migration of the national economic center, coupled with the flourishing Maritime Silk Road, established Guangdong as a critical gateway for foreign trade. Consequently, the proliferation of ICH items in the Pearl River Basin fundamentally altered the direction of the centroid’s movement. Subsequently, during the Ming and Qing dynasties, an increase in ICH originating from inland areas induced a slight westward shift in the distribution centroid.

In the Modern era, the reopening of coastal ports and the resumption of foreign cultural exchanges facilitated the global dissemination of artistic forms such as Quanzhou Paper Cutting and Puppet Head Carving. Consequently, the distribution center of ICH shifted eastward once again.

Significant variation exists in the spatial distribution of ICH across different eras, with the directional orientation predominantly exhibiting a Northeast-Southwest trend. From the Pre-Qin to the Han and Jin periods, the distribution range showed a pattern of contraction accompanied by an eastward shift (Fig. 3c). Specifically, the SDE for the Pre-Qin period was characterized by a rotation angle of approximately 80 ° and an area of roughly 370,000 km². In comparison, the SDE area for the Han and Jin period decreased by about 70,000 km², suggesting that societal turmoil during this time exerted a detrimental impact on ICH development. During the Sui and Tang periods, a substantial number of ICH items emerged in Guangxi and Fujian; consequently, the SDE exhibited high ellipticity, reaching 0.73. From the Song-Yuan period through the Qing dynasty, the spatial extent of ICH expanded significantly, with SDE areas consistently exceeding the 350,000 km² threshold. Concurrently, the ellipticity of the distribution ellipses continued to decline, reaching its lowest value (0.709) in the Ming Dynasty before increasing again in the Qing Dynasty. In the Modern era, the scarcity and dispersed distribution of newly originated ICH items led to a contraction in the SDE area and an increase in ellipticity.

Overall, the spatial distribution of ICH across the three provinces exhibits a fluctuating eastward migration, closely correlated with social transitions. The trajectory of the center of gravity displays distinct phasic characteristics: moving eastward from the Pre-Qin period to the Sui and Tang Dynasties, shifting southwest from the Song and Yuan to the Qing Dynasties, and rebounding eastward in the modern era, driven by external exchanges. In terms of spatial morphology, the ICH distribution has maintained a consistent Northeast-Southwest orientation, following a pattern of first contraction, then expansion, and then contraction again. Specifically, in the early stage, the distribution ellipse was small in range with high ellipticity, indicating a concentrated distribution that reached its peak during the Sui and Tang Dynasties. From the Song and Yuan to the Qing Dynasties, the range was most extensive while ellipticity decreased, suggesting a trend toward spatial equilibrium. In the modern era, the ellipticity of the ellipse increased, presenting a dispersed distribution of ICH. Consequently, it is concluded that civilizational expansion and social upheaval exert a significant influence on the spatiotemporal patterns of ICH.

Temporal evolution trend of inter-provincial differences of ICH

A provincial-scale analysis reveals a consistent southward migration in the centers of gravity and spatial extents of ICH across the examined provinces (Fig. 4). Guangxi exhibits minimal displacement, albeit with a subtle southward trajectory. The pattern in Guangdong is characterized by predominant east-west oscillations superimposed on a net southward shift. Conversely, Fujian displays a clear north-south oscillatory movement, culminating in an overall southward displacement.

Fig. 4: Diagram of differences in the temporal evolution of ICH across provinces.

a–c represent Guangxi Province, d–f represent Guangdong Province, and g–i represent Fujian Province. The colored triangles represent the centers of gravity, and the colored outlines represent the standard deviational ellipses. Different colors correspond to specific historical periods: red for Pre-Qin, salmon for Han and Jin, yellow for Sui and Tang, green for Song and Yuan, blue for Ming, pink for Qing, and purple for Modern times. b, e, h show the overall elliptical positions and centers of gravity for each respective province, with grey rectangular boxes indicating the enlarged areas. a, d, g provide enlarged views detailing the shifts of the ellipses. c, f, i provide enlarged views detailing the movement paths of the ICH centers of gravity, connected by black arrows. Movement paths of the ICH centers of gravity, connected by black arrows.

Guangxi is situated in the western part of the study area. Across the seven historical periods, the spatial displacement of its center of gravity was relatively minor, with all centroids falling within Laibin City, exhibiting a continuous trend of migration toward the southeast (Fig. 4a–c). Temporally, the shift was most pronounced between the Pre-Qin and the Han and Jin periods, reflecting substantial cultural exchange or population migration during this phase. Regarding spatial morphology (Table 4), the SDE of ICH in Guangxi predominantly covered the central region across all periods. Before the Modern era remained relatively stable between 110,000 and 135,000 km², peaking during the Qing Dynasty (approximately 132,244 km²). This peak indicates that ICH diffusion reached its maximum extent, with the strongest cultural radiation effects occurring during this period. In Guangxi, mountains and hills account for more than 70% of the terrain. In particular, the complex terrain in the north and west (such as the Shiwan Mountains and Daming Mountains) restricts the spatial clustering of ICH, resulting in a strong randomness in its types and distribution, with local clustering characteristics only appearing in the southeastern basin.

Table 4 Gravity center of Guangxi

The centroid trajectory of ICH in Guangdong follows a discernible east-west oscillation, superimposed on a gradual southward displacement over the study period (Fig. 4d–f). Over the seven historical periods, the centroid accumulated a total displacement of approximately 253.51 km (Fig. 5). Notably, the centroids for the Han and Jin and Sui and Tang periods exhibited more pronounced fluctuations than those of other eras, characterized initially by a sharp eastward and northward shift, followed by a southward turn. This trajectory reflects a structural transformation from an inland agrarian society to a maritime commercial culture, embodying the transition from interior development to oceanic trade. Regarding spatial extent (Table 5), the SDE area fluctuated between approximately 68,000 and 103,000 km². The period of maximum spatial extent was the Sui and Tang, peaking at 103,870 km², which corresponds to a phase of heightened cultural activity. In contrast, the Ming Dynasty saw the distribution area contract to approximately 77,956 km², indicating a corresponding shift toward a more spatially concentrated pattern. This contraction was primarily driven by the maritime prohibition policy in the early Ming period, which restricted the scope of cultural exchange and limited foreign cultural input. From the middle of the Ming Dynasty onward, Guangdong’s demographic and economic center increasingly gravitated toward the Pearl River Delta and coastal ports, fostering a high-density cultural sphere centered on Cantonese culture. The intense aggregation of ICH items in these regions resulted in a reduced SDE area but a marked increase in distribution density.

Fig. 5: ICH center of gravity shift distance across different provinces.

The stacked horizontal bar chart illustrates the shift distances (in kilometers) for Guangxi, Guangdong, and Fujian provinces. Different colors represent the shift distances during specific historical periods: red for Pre-Qin, salmon for Han and Jin, yellow for Sui and Tang, green for Song and Yuan, light blue for Ming, pink for Qing, and purple for the Modern period. The numbers within each colored segment indicate the shift distance for that specific period, and the grey numbers at the end of the bars represent the total shift distance for each province.

Table 5 The gravity center of Guangdong

The gravity center of ICH in Fujian exhibits a ‘North-South oscillatory pattern with an overall southward displacement’ (Fig. 4g–i). Specifically, the centroid has shifted about 70 km to the southwest, with a cumulative displacement of approximately 230.06 km (Fig. 5). The southward shifts were most pronounced during the Han and Jin and Modern periods, spanning roughly 55 km and 60 km, respectively. Conversely, slight northward movements occurred during the Sui, Tang, Song, and Yuan periods. During the Han and Jin, Song, and Yuan periods, the center of gravity gravitated toward the interior, largely under the influence of regime transitions and social turbulence; consequently, ICH items originating in these eras were predominantly located in inland mountainous and hilly areas. Regarding spatial distribution (Table 6), the area of the Standard Deviational Ellipse (SDE) fluctuated between approximately 44,800 and 64,600 km², reaching a maximum in the Ming Dynasty (about 64,685 km²) and a minimum in the Modern era (about 44,859 km²). Notably, in the Pre-Qin, Sui and Tang, Qing, and Modern periods, the SDEs exhibited high ellipticity, with their major axes aligned parallel to the coastline. This orientation indicates that coastal regions experienced stronger developmental momentum than inland areas during these periods, underscoring the intrinsic link between the evolution of maritime culture and the formation and development of ICH.

Table 6 Gravity Center of Fujian

At the provincial scale, ICH in Fujian, Guangdong, and Guangxi exhibits a shared tendency toward overall southward migration. However, distinct physical geographies and historical trajectories give rise to divergent evolutionary paths. In Guangxi, the center of gravity remains relatively stable with only a minor southeastward drift, reflecting the constraining effect of mountainous terrain on the distribution of ICH. Guangdong is characterized by ‘east and west fluctuations accompanied by a slight southward shift,’ a migration pattern intrinsically linked to population inflows from the Central Plains and the expansion of maritime trade. Fujian, by contrast, displays a ‘north and south oscillatory pattern with an overall southward displacement,’ underscoring the strong influence of coastal culture. Overall, the prosperity of coastal trade, population migration, and topographic conditions are key determinants driving the evolutionary trajectory of ICH centers of gravity across the three provinces.

Our multiscale spatiotemporal analysis indicates an evolutionary trajectory for ICH in the study area characterized by a southward-moving centroid and coastal concentration. This pattern was fundamentally shaped by repeated, large-scale southward population migrations. Historical crises, including the Turmoil of the Eight Princes in the Western Jin, the An-Shi Rebellion in the Tang, and the Southern Song relocation, prompted sustained inflows of people from the north, thereby continuously introducing northern cultural elements and reinforcing the observed spatial trends. Migration flows since the Han and Jin period not only provided an abundant labor force but also introduced advanced production technologies and cultural traditions, thereby propelling the prosperity of agriculture, handicrafts, and commerce. By the Ming and Qing Dynasties, oceanic trade and foreign exchanges reached a zenith, further reinforcing the economic and cultural dominance of the coastal zones. Consequently, this region gradually evolved into a pivotal economic and cultural center.

Spatial aggregation characteristics

The ICH of the three southeastern provinces exhibits a clustered spatial pattern. For all ICH categories, NNI is below 1, indicating significant spatial agglomeration. However, the intensity of clustering varies across categories. Traditional handicrafts (NNI = 0.290) and Folk customs (NNI = 0.307) are among the most strongly clustered of the ten categories reported in Table 7 and can be regarded as representative types characterized by pronounced spatial concentration.

Table 7 Results of nearest neighbor analysis of ICH in the southeastern coastal areas of China

Traditional handicrafts, with an NNI of 0.29, display the strongest spatial clustering among all ICH categories, highlighting a pattern deeply rooted in localized resource dependence and pronounced regional identity. Many Traditional crafts emerged from and remain dependent on localized mineral resources. A prime example is Dehua ceramics in Fujian, which developed along a kaolin-rich belt and, since the Song dynasty, has operated under a “one kiln, multiple workshops” model—a single kiln supporting numerous specialized pottery workshops. Regional social structures further constrain the diffusion of these crafts. Familial rules that restrict the transmission of specialized architectural knowledge to direct heirs severely limit the pool of practitioners and the geographical spread of the craft, thereby heightening its risk of disappearance. Owing to such resource dependence, localized cultural frameworks, and inherently limited capacity for wider dissemination, Traditional handicrafts constitute a vulnerable category of ICH that requires sustained and focused protection.

Folk customs and Traditional music exhibit high spatial clustering, with NNI values of 0.307 and 0.473, respectively. Unlike Traditional handicrafts, the diffusion of these categories is constrained primarily by barriers to cultural exchange. Our analysis shows that both are closely aligned with the linguistic landscape of the study area, with the most pronounced clustering occurring in the Min and Yue dialect regions. In the case of Folk customs, the “Sending Off the King Boat” ritual in the Southern Min (Minnan) cultural area is performed entirely in the Quanzhou variety of the ancient Minnan dialect, whose prayers preserve numerous phonological elements dating back to the Tang and Song dynasties. This creates a linguistic barrier that limits the ritual’s spread, resulting in its dense concentration along the Quanzhou coast. Traditional music is even more tightly embedded in dialect systems. Dialects serve not only as the medium through which these musical traditions take shape and evolve but also as the cultural boundary that constrains their transmission. The widespread adoption of Mandarin has coincided with a marked decline in dialect vitality. ICH forms embedded within dialect-based cultures are particularly vulnerable, often being the first to experience disruptions in their intergenerational transmission. This vulnerability places them at an elevated risk of extinction, thereby constituting a distinct category of ICH that necessitates targeted and enhanced conservation efforts.

Quyi (NNI = 0.682) represents an ICH category characterized by weak spatial clustering and high inherent mobility. This dispersed distribution pattern stems from the capacity of such cultural elements to transcend geographical barriers and adapt to varied socio-environmental contexts. A representative case is the Red Boat Opera troupes of the late Qing and early Republican periods, which travelled along the Xijiang River and staged around 150 Cantonese opera performances annually, thereby widely disseminating performing arts culture. These low-clustering ICH categories provide empirical support for a positive relationship between the mobility of cultural elements and the degree of spatial dispersion in their spatial patterns.

Overall, the clustering patterns of ICH in the southeastern provinces reveal a key dichotomy rooted in cultural resilience and adaptability. Strongly clustered types are largely shaped and confined by place-specific factors, such as local resources, artisanal techniques, and customary practices. Weakly clustered types, however, operate with greater mobility. Their historical development is marked by the ongoing incorporation of external influences and endogenous renewal, processes that build wider cultural resonance and facilitate spatial expansion.

Spatial density distribution patterns

We calculated the theoretical optimal bandwidth for ten categories of intangible cultural heritage using two-dimensional empirical rules. The results show that the average theoretical optimal bandwidth for these ten categories of intangible cultural heritage is 100.0 km. Therefore, we selected 100 km as the kernel density bandwidth for this study.

The results of the KDE analysis show that the distribution of ICH exhibits a clear regional clustering. Across the ten ICH categories, their spatial density patterns can be classified into three distinct structural patterns: dual-core, triple-core, and multi-core structures.

The dual-core pattern is identified in the region stretching from the Pearl River Estuary to eastern Fujian. It is predominantly associated with four ICH categories: Traditional dance, Traditional arts, Quyi, and Traditional sports, recreation, and acrobatics (Fig. 6a–d). The southern core is situated at the Pearl River Estuary (within the 200 km radiation radius of the Pearl River Delta), covering the Cantonese cultural zone centered on Guangzhou and Foshan. With a high river network density of 0.8 km/km², the convenient inland waterway system formed by the Xijiang and Beijiang rivers has not only nurtured traditional arts such as the Lion Dance and Puppetry, but also leveraged the intersection of river and sea to serve as a pivotal hub for the global dissemination of Cantonese culture, facilitating a high degree of ICH clustering. Specifically, Traditional Dance exhibits the most extensive distribution, with its core proximal to the estuary. This pattern is driven by two factors: the vast water bodies provide a natural stage for Dragon Boat Parades, and historically, as a vital commercial gateway, the Pearl River Estuary integrated Traditional Dance into Qing Dynasty trade fairs as fixed performances, further reinforcing its spatial concentration in port areas. The northern core spans the southeastern coast of Fujian and eastern Guangdong, covering key nodes such as Fuzhou, Xiamen, and Shantou. Distinct internal spatial differentiation is evident among the ICH categories in this region: high-density clusters of Traditional Dance and Traditional Arts are concentrated primarily near the estuaries of the Hanjiang and Rongjiang rivers (around Shantou); conversely, Qu Yi and Traditional Sports, Recreation, and Acrobatics extend northward into the Minjiang River basin (around Fuzhou), forming a continuous agglomeration belt along the Fuzhou-Xiamen coast.

Fig. 6: Diagram of the spatial distribution pattern of ICH.

The maps illustrate the density distributions categorized into three main spatial patterns: a–d represent the dual-core distribution, e–g represent the triple-core distribution, and h–j represent the multi-core distribution across various ICH categories. The background color gradient indicates the spatial density levels: pale yellow for sparse areas, light green for relatively sparse areas, light blue for relatively dense areas, and dark blue for dense areas.

The triple-core distribution pattern spans a corridor linking Nanning, the Pearl River Delta, and the southern coast of Fujian, primarily comprising three ICH categories: Folk Literature, Traditional Medicine, and Folk Customs. The Nanning core area is centered on the Nanning Basin (Fig. 6e–g), where Folk literature demonstrates the highest degree of spatial agglomeration. Nanning hosts 18 Folk literature items, accounting for 29% of the total in Guangxi. The city lies at the confluence of the Zuojiang and Youjiang rivers, forming a distinctive V-shaped cultural corridor. The surrounding mountains have facilitated the transmission of Zhuang folk songs and similar traditions while also providing a degree of isolation that has aided in preserving local forms like Folk Literature. The Pearl River Estuary core contains a high concentration of Folk custom items, supported by the dense river network of the Pearl River Delta, which creates a natural setting for water-based folk activities such as the Foshan Dragon Boat Races and the Guangzhou Boluo Dan Festival. The coastal core in southern Fujian lies furthest to the north, with Xiamen forming the principal concentration of Folk literature and Folk custom ICH. This reflects Xiamen’s position at the mouth of the Jiulong River and its historical role as a key node on the Maritime Silk Road Serving as a long-standing window for cultural exchange between China and foreign nations, the city has nurtured a rich abundance of Folk literature and Folk custom and a long-standing gateway for Sino-foreign cultural exchange, which has nurtured a rich body of literary and folk ICH. Traditional medicine ICH is most densely distributed around Fuzhou, where local climate and topography strongly influenced its development. Located in the lower Min River basin, backed by the Wuyi Mountains and facing the East China Sea, Fuzhou has a subtropical maritime monsoon climate that provides ideal conditions for the growth of medicinal plants, fostering the concentration of traditional medical practices. Notably, within this triple-core pattern, each of the three ICH categories forms a core area in every province of the study region, and these areas largely coincide with zones of high population density, underscoring the close connection between this heritage and local daily life.

The multi-core distribution pattern is primarily composed of three ICH categories, namely traditional drama, Traditional handicrafts, and Traditional music, and its core areas are spatially diverse (Fig. 6h–j). While most cores coincide with known regional hotspots such as southern Fujian, the Pearl River Estuary, and Nanning, some exhibit distinct spatial configurations. Traditional drama forms around five high-density clusters. Notably, it includes the northernmost cluster among all ICH categories, located in Pingnan County, Fujian (27 °N). Situated in the mountainous interior of eastern Fujian, Pingnan’s relative inaccessibility has historically insulated local theatrical traditions from external influences, fostering the preservation of diverse genres such as Siping, Pingjiang, and Luantan operas. Conversely, Traditional Drama is the only category that shows no significant clustering within the economically advanced Pearl River Delta. This absence may be attributed to the region’s fast-paced urban lifestyle and potentially weaker contemporary social impetus for sustaining such time-intensive performing traditions. Traditional handicrafts cores are largely concentrated along the southeastern coast, which has long shorelines and abundant marine resources. These coastal zones historically hosted active trade ports, and industries such as fishing and salt production encouraged the development of associated crafts, including shipbuilding, fishing net weaving, and sea salt processing. In contrast, the mountainous terrain and historically constrained transportation networks in Guangxi have limited the agglomeration of such production-oriented crafts. Traditional Music shows a broader distribution than Crafts, with additional clusters in Guangxi’s multi-ethnic zones. For instance, Zhongshan County, home to 21 ethnic groups, demonstrates how cultural confluence fosters ICH density. The interaction between Han, Yao, Zhuang, and other communities has synthesized unique musical forms such as the Butterfly Song, directly contributing to the region’s high ICH tally.

Overall distribution patterns and regional differentiation

Based on the integrated analysis of the NNI and KDE, the ICH in Guangdong, Guangxi, and Fujian demonstrates pronounced spatial agglomeration, manifesting in diverse multi-core distribution patterns (Fig. 7).

Fig. 7: Diagram of the density distribution relationship of ICH.

The figure illustrates the correlation between Nearest Neighbor Index (NNI) analysis on the left and Kernel Density Estimation (KDE) analysis on the right for various ICH categories. In the NNI analysis section, ICH types are classified into three density levels indicated by yellow-toned boxes: dark yellow for High-density, yellow for Mid-density, and light yellow for Low-density, alongside their corresponding numerical values. In the KDE analysis section, the spatial distribution patterns are classified into three core types indicated by blue-toned boxes: dark blue for Multi-core, medium blue for Triple-core, and light blue for Dual-core, accompanied by their respective miniature spatial density maps.

Statistical analysis further reveals significant variation in both the intensity of spatial clustering and the number of core areas across different ICH categories. A notable positive correlation exists between these two metrics for certain types. Traditional handicrafts and Folk customs show the lowest NNI values, reflecting the strongest clustering, and their KDE results are predominantly multi-core, suggesting a pattern of regional connectivity and multi-nodal diffusion. In contrast, Traditional arts and Quyi display the weakest clustering, with few core areas and relatively scattered distributions. Traditional music, dance, and drama often show dual-core or triple-core arrangements, which point to relatively high regional concentration but limited inter-regional dissemination. Overall, a greater number of core areas is associated with stronger spatial clustering. This points to a coupled relationship between the spatial intensity of cultural practice and its geographic spread. These findings illuminate the polycentric structure of cultural development in China’s southeastern coastal region and underscore the expansive dynamics of its underlying socio-cultural networks.

From an inter-provincial perspective, categories such as Traditional dance, Traditional fine arts, Traditional handicraft, Traditional sports, recreation and acrobatics, and Quyi exhibit a low degree of agglomeration in Guangxi. In Guangdong, all ICH categories demonstrate clustering characteristics, except for Traditional drama, which is relatively dispersed. In contrast, most ICH categories in Fujian are densely distributed along the coastal belt, whereas Traditional dance has not formed significant clustering.

Constrained by geographical conditions, the distribution of most ICH items in Guangxi is dispersed. Dominated by mountains and hills with complex topography and limited accessibility, this geographically insular environment has, to some extent, preserved the diversity of ethnic minority cultures but has also led to a fragmented cultural landscape. Simultaneously, long-term isolated development has resulted in numerous linguistic enclaves within the province, further increasing the difficulty of cultural exchange. Consequently, ICH items are often concentrated in specific villages or restricted areas, making it difficult to form large-scale agglomerations and posing challenges to their transmission and identification.

In contrast, Guangdong presents an almost opposite pattern. As one of China’s earliest gateways to the outside world, the province contains ICH that spans nearly all major categories, a pattern that is closely tied to its long-standing openness. Serving as a confluence of Central Plains and maritime cultures since the Qin and Han dynasties, Guangdong’s role intensified during the Ming and Qing eras. Guangzhou, in particular, emerged as a pivotal hub for foreign trade, channeling a continuous flow of external cultural influences into the region.

The notable absence of a significant cluster of Traditional dance in Fujian is closely linked to the province’s socio-religious context and historical economic drivers. Along the coast, ICH is dominated by Traditional handicrafts, Folk customs, and Traditional drama, categories that are strongly tied to maritime trade and local belief systems. Traditional dance does exist, but is mostly embedded within ritual activities rather than practiced as an independent performing art. Historically, the coastal economy relied heavily on fishing and commerce, which produced high levels of population mobility and relatively loose community structures. This environment provided neither a stable participant base nor consistent settings for transmission, preventing Traditional Dance from evolving into a widely practiced or geographically concentrated ICH form.

Index system for influencing the evaluation of the ICH distribution

The spatial distribution of ICH, a vital manifestation of cultural diversity and human creativity, is shaped by an interplay of physical and human geography elements. Focusing on Fujian, Guangdong, and Guangxi provinces, this study establishes a framework of 16 influencing factors (Table 8). These factors include physical geography elements (elevation, NDVI, landform, climatic regionalization, annual mean temperature and precipitation, water system, and coastline) and human geography elements (traffic, resident population, urbanization rate, GDP, number of museums, nationally famous historical and cultural towns and villages, and education level). To identify the dominant factors underlying the spatial distribution of ICH, we employed the factor detector module of the Geodetector. The explanatory power of each factor was quantified by its q-value, enabling the identification of key drivers of ICH distribution at the municipal scale.

Table 8 Index system of influencing factors of the spatial pattern of ICH

Detection of single-factor driving forces

Factor detection results indicate that both physical and human geography factors were statistically significant (p < 0.05) in explaining ICH distribution. The average q-values for human and physical factors are 0.34 and 0.32, respectively, with human geography factors having a stronger explanatory power. The factors ranked by their q-values are: water System (0.609), resident population (0.504), annual mean precipitation (0.491), followed by traffic, annual mean temperature, elevation, language partition, coastline, urbanization rate, national famous historical and cultural towns and villages, education level, GDP, landform, number of museums, NDVI, and climatic regionalization. The three factors with the highest q-values, water system, resident population, and annual mean precipitation, are therefore established as the dominant drivers (Fig. 8).

Fig. 8: Results of ICH factor detection.

The horizontal bar chart displays the q-values for various driving factor variables (labeled X1 through X16). The light green bars highlight the top three variables with the highest q-values (X7, X10, and X6), indicating the most significant influence, while the remaining variables are represented by light grey bars. The specific numerical q-value for each factor is indicated at the end of its respective bar.

Among the physical geography factors, water system, annual mean precipitation, and temperature are the three dominant factors influencing the spatial distribution of ICH. Elevation, coastline, and landform type serve as secondary importance factors, while NDVI and climatic regionalization are weakly influencing factors. The density of river networks in the whole study area is significantly positively correlated with the distribution of ICH. The spatial distribution of ICH in these provinces is primarily shaped by the river systems and high precipitation levels in the humid climate, which have fostered numerous ICH clusters along major river basins such as the Min and Pearl Rivers. The river networks not only provide the material basis for livelihoods but also facilitate cultural exchange through riverine trade and transport. The development of Traditional handicrafts, such as Fuzhou Bodiless Lacquerware, has benefited from the material flow facilitated by the Min River navigation, while the prosperity of dragon boat racing culture in Foshan and Guangzhou is deeply rooted in the rich cultural space provided by the river network in the Pearl River Delta. Driven by abundant Annual mean precipitation and favorable temperatures, the three southeastern provinces of China have developed a humid subtropical monsoon climate. Favorable hydrothermal conditions facilitated the development of paddy agriculture in southern China, giving rise to distinctive ICH such as terrace construction techniques, and culminating in a unique ICH landscape. Elevation, coastline, and landform also play a secondary yet distinct role in influencing ICH distribution. Topographically, the east is characterized by plains and hills, in contrast to the high mountains and basins of the west. Flatter landscapes tend to support more intensive cultural activities, whereas the relative isolation of mountainous basins has conversely aided in preserving indigenous ICH.

The human geography factors exert a significant shaping influence on the spatial distribution of ICH. Among them, the explanatory power of resident population, traffic, and language partition all exceed 0.3, constituting the core driving forces for ICH agglomeration. Densely populated areas typically possess richer cultural resources and higher vitality in cultural heritage transmission. In such regions, cultural activities are more frequent, the economy is more developed, and government efforts for the exploration and preservation of ICH receive greater emphasis. Well-developed transportation networks facilitate the dissemination and exchange of ICH, attract visitors and cultural practitioners, and promote cultural tourism, thereby providing economic support for ICH protection and transmission. Language serves as a vital carrier of culture, and cultural traditions, and ICH exhibits significant differences across different language zones. Our research reveals that dialect zoning constructs potential boundaries for ICH transmission. Specifically, the dissemination range of Cantonese Opera overlaps highly with the Guangfu dialect area, while the Minnan dialect zone frames the core distribution areas of Nanyin and Gaojia Opera, resulting in the formation of unique cultural ecologies within different linguistic regions.

Multi-factor interactive driving mechanisms

The spatial distribution of ICH is influenced by the complex interaction of multiple natural and human factors. To quantitatively analyze these relationships, this study utilized the interaction detector of the Geodetector model. This approach allows us to measure the interactive effects between paired factors, revealing whether their combined influence on the dependent variable demonstrates synergistic enhancement or weakening. Specifically, we assessed both the individual explanatory power and the bivariate interactive effects of 16 pre-selected driving factors (X1-X16) to identify statistically significant interactions among them.

The interaction matrix depicts the pairwise interaction detector results among the 16 drivers. The value in each cell represents the interaction q-value between the two variables. This q-value quantifies their combined ability to explain the dependent variable. A higher value indicates stronger interaction (Fig. 9).

Fig. 9: Results of interactive detection of ICH influencing factors.

The matrix displays the interaction between various driving factors (labeled X1 through X16). The upper right section of matrix shows the numeric interaction q-values, where the background color gradient represents the magnitude: orange indicates lower values (approaching 0), while dark green indicates higher values (approaching 1). The lower left section shows the interaction types using symbols: green double upward arrows denote Nonlinear Enhancement, yellow single upward arrows denote Bivariate Enhancement, and orange downward arrows denote Nonlinear weakening. The areas marked by the red dashed lines highlight the results of interactions specifically between natural and human factors. NDVI stands for Normalized Difference Vegetation Index, and GDP stands for Gross Domestic Product.

The spatial differentiation of ICH is not driven by the independent action of a single factor but is the result of the complex coupling of multiple factors. Analysis results from the interaction detector indicate a widespread and significant mutual reinforcement effect among the driving factors of ICH in the southeastern coastal region of China, with pairwise interaction results primarily manifesting as nonlinear enhancement and bivariate enhancement. Notably, the interaction between the Water System and GDP yields the highest explanatory power, reaching 0.90. Developed water networks provide the material basis and transportation channels, while a dynamic regional economy facilitates the circulation and exchange of resources; the synergistic effect of these two is the key factor determining the high agglomeration of ICH in this region.

The study reveals a significant synergistic effect between the natural environment and socio-humanistic factors, as interactions between these two categories of factors are prone to exhibiting nonlinear enhancement. Specifically, the interactions between Language Zoning and five natural factors (elevation, NDVI, landform, climate, and annual mean temperature) all demonstrated significant nonlinear enhancement. This finding indicates that the spatial distribution of ICH is the result of a deep coupling between cultural elements and the natural and human environments. Specifically, the interaction q-value is highest for annual mean temperature (q = 0.78), followed by elevation (q = 0.77) and geomorphology (q = 0.58). The driving mechanisms behind this phenomenon are twofold. First, topography constrains cultural exchange. In western regions characterized by high altitude and complex geomorphology, rugged terrain limits population mobility. This fosters highly fragmented and diverse dialect zones, creating an enclosed environment that preserves a wide variety of ICH types, resulting in a scattered spatial distribution. Second, climatic conditions determine the environment for cultural continuity. Favorable temperature conditions imply higher ecological carrying capacity and agricultural potential. This not only increases the frequency of dialect usage but also provides a stable material and social foundation for the living transmission of ICH and the organization of cultural activities.

Differences in dominant factors across ICH categories

The Geodetector was employed to quantify the explanatory power of factors influencing ten types of ICH across the three provinces (Fig. 10). The factor q-values from each quantification were ranked. The three most influential factors in each ranking (selected from a total of 16 factors) were designated as dominant factors (Table 9). The analysis revealed that the water system factor emerged as a dominant factor in eight out of the ten quantifications, demonstrating significant explanatory power for the distribution of eight ICH categories. It suggests that the distribution of water systems exerts a universally positive effect on the emergence and development of diverse ICH forms, establishing it as the predominant factor shaping ICH spatial distribution in the study area. The paramount importance of the water system can be attributed to its multifaceted roles in providing essential natural resources, facilitating transportation, and fostering cultural exchange.

Fig. 10: Results of detection of ten types of ICH factors.

The multi-panel figure consists of ten horizontal bar charts, each representing a specific ICH category (Traditional handicraft, Folk custom, Traditional drama, Traditional music, Traditional Art, Traditional dance, Traditional sports, recreation and acrobatics, Traditional medicine, Folk literature, and Quyi). Each chart displays the interaction q-values (horizontal axis) for various influencing factor variables (labeled X1 through X16 on the vertical axis). Within each chart, the dark green bar highlights the variable with the highest q-value, indicating the most dominant driving factor for that specific ICH type, while the remaining variables are represented by light grey bars. The specific numerical q-value is indicated at the end of each bar.

Table 9 Frequency of dominant factors for ICH Types

The resident population and traffic were also identified as critical factors, each appearing as a dominant factor in five analyses. This suggests that cultural activities tend to be more active in densely populated areas, and that accessibility facilitated by transport networks promotes cultural dissemination. NDVI and annual mean precipitation ranked among the top three factors in four and three analyses, respectively, indicating that natural environmental conditions and climate also affect the distribution of certain ICH types. Conversely, the number of museums, GDP, coastline, education level, and annual mean temperature each emerged as a dominant factor only once, corresponding to Traditional dance, Traditional art, Traditional sports, Medicine, and Traditional art, respectively. This indicates that these factors influence the distribution of only specific ICH types and lack universality. For instance, the high q-values associated with the coastline (X8) were observed exclusively during the analysis of the Traditional sports, recreation, and acrobatics category, suggesting that the unique geographical environment of maritime regions holds particular significance for these practices. Overall, these findings demonstrate that the water system, resident population, and Traffic are universal drivers significantly influencing ICH distribution across all categories. While natural environment and climatic conditions also exert influence, other factors generally have a minor overall impact. These conclusions provide a scientific basis for the preservation and transmission of ICH, aiding in the improved understanding and protection of this valuable cultural heritage.

Discussion

History carries collective memory and cultural heritage, while culture sustains social identity and the transmission of values. As a living carrier of national culture, ICH encapsulates profound cultural imprints. The ICH in China has undergone a development process over thousands of years. This long-term accumulation has resulted in the patterns of regional differentiation. Approaching from a geographical perspective, this study integrates GIS spatial analysis techniques and historical interpretation to comprehensively analyze the spatiotemporal evolution and distribution patterns of 2372 ICH items across seven historical periods in Southeast Coastal China. Furthermore, the study explores the underlying mechanisms driving this spatial distribution.

In terms of the study area, this study focuses on the regional characteristics of ICH evolution and selects three south-eastern coastal provinces of China as the study area. This region possesses significant geographical representativeness and clear research advantages. First, the study area offers a balanced perspective, combining macro-scale representativeness with local-level exactness. This avoids both the problem of low precision in national-scale studies and the problem of cultural regional fragmentation in provincial-scale studies⁴⁰. Secondly, the region has a dense network of waterways, diverse terrain, and complex and varied cultural types. It preserves the legacy of the southward migration of Central Plain culture, while also demonstrating an integration of maritime culture and localized Lingnan traditions. Consequently, the diverse cultural integration in this region makes it an ideal area for exploring marine ICH.

In terms of spatiotemporal evolution, consistent with existing studies⁶¹, our research demonstrates that the evolution of ICH is closely associated with the southward migration of population, shifts of economic center, and the development of maritime trade. This study found that, in the long-term macro-evolution, the center of gravity of ICH in the study area has shown a fluctuating eastward migration pattern. The independent centers of gravity of the three provinces all show a migration pattern of southward shift. Previous studies in the literature have mostly focused on static spatial analysis⁶² and have given less consideration to the dynamic characteristics of ICH distribution.

Regarding spatial agglomeration characteristics and distribution patterns, this study finds that ICH resources exhibit significant spatial clustering overall (NNI < 1), with coastal port cities serving as high-density zones for cultural heritage. This finding is highly consistent with previous research^10,63. Furthermore, by synthesizing the results of the NNI and KDE, we observed that ICH has formed continuous agglomeration belts centered around key cities such as Guangzhou, Fuzhou, and Quanzhou. Over the lengthy historical process, the spatial distribution of various ICH categories has evolved across provincial boundaries into structured agglomeration patterns characterized by dual-, triple-, and multi-core configurations. This structural evolution is profoundly correlated with the distinct cultural attributes and geographical adaptability inherent to different ICH types. The study also uncovered a critical underlying pattern: a positive correlation exists between the number of high-density core areas of a specific ICH category and its overall spatial agglomeration intensity. For instance, traditional handicrafts (NNI = 0.29) display a quintessential multi-core distribution, emerging as a contiguous multi-core corridor that links the Nanning Basin, the Pearl River Delta, and the Minnan Coast. The trans-provincial multi-center pattern revealed in our study significantly diverges from research constrained by single administrative divisions^22,23,25, which tends to conclude that ICH forms highly concentrated single-core clusters exclusively around individual political or economic centers. We argue that the transmission and diffusion of ICH rely extensively on crisscrossing inland water systems, such as the Xijiang and Minjiang rivers, coupled with expansive coastal port networks. These geographical features forge interconnected cultural transmission corridors that effectively overcome the spatial barriers imposed by administrative boundaries, thereby shaping the contemporary multi-core cultural landscape.

At the level of single-factor detection concerning driving mechanisms, the results reveal significant heterogeneity among the core driving factors across different ICH categories. From an overarching perspective, the collective explanatory power of human factors, such as resident population and transportation networks (average q = 0.34), slightly outweighs that of natural factors (average q = 0.32). Through the individual detection of the ten ICH categories, we identified water systems and resident population as universal factors influencing the distribution of all categories, a finding consistent with previous research^64,65. However, a highly innovative finding of this study is that certain environmental and human factors exhibit a pronounced “anchoring effect.” Specifically, these factors demonstrate exceptionally high explanatory power exclusively for specific ICH categories while exerting negligible influence on others. For instance, the analysis demonstrates that “coastline length” exhibits exceptionally high explanatory power (indicated by its high q-value) uniquely in the distribution of traditional sports, recreational activities, and acrobatics, whereas the “number of museums” exerts a category-specific impact on traditional dance. This finding fundamentally overcomes the profound limitations of prior literature^30,66, which often conceptually treated ICH as a homogeneous entity and resorted to macroscopic causal attribution. By revealing the asymmetrical dependence of diverse ICH types on socio-environmental factors, this study establishes a robust quantitative foundation for formulating precise, category-specific conservation policies.

Another significant contribution of this study lies in elucidating the profound impact of multi-factor interactions on the spatial distribution of marine ICH within the study area. We posit that the formation of ICH spatial patterns is the consequence of the long-term coupling of diverse natural and human elements; thus, no single variable can adequately account for its complex genesis. By employing the interaction detector, our analysis reveals that interactions between any two factors predominantly manifest as bivariate or nonlinear enhancement. The combined explanatory power of these mutually interacting variables consistently supersedes the impact of any individual factor. Notably, when the “water systems” factor interacts with “GDP,” “linguistic zoning,” and “population distribution,” it generates exceptionally strong synergistic enhancement effects (q > 0.8). This leads to the conclusion that coupling natural and human dimensions significantly amplifies the capacity to explain ICH spatial distribution. This finding fundamentally diverges from previous research relying on traditional linear regression models that focus predominantly on the independent impacts of isolated variables^34,36. Such prior studies have frequently treated GDP, topography, or specific environmental metrics as singular dominant determinants of cultural distribution. Contextualized within the marine cultural region of Southeast Coastal China, the formation, preservation, and spatial diffusion of ICH are evidently not dictated by isolated economic advantages or geographical constraints. Rather, they are profoundly shaped by a composite cultural transmission network intricately woven by dense river systems, historical maritime trade, population agglomeration, dialectal diversity, and robust economic levels.

In conclusion, marine ICH in Southeast Coastal China demonstrates distinct spatiotemporal characteristics defined by the fluctuating southward migration of its gravity center and a multi-core agglomeration pattern. Crucially, this spatially heterogeneous landscape is predominantly driven by the synergistic interactions between natural environmental and socioeconomic factors. By transcending the conventional limitations of focusing on single ICH categories or isolated administrative divisions, this study elucidates the profound impacts of material dependence, dialectal barriers, and multidimensional interactive networks on the driving mechanisms of ICH from a trans-regional perspective. Ultimately, these findings establish a robust scientific foundation for optimizing ICH governance and fostering sustainable cultural development within the region. Furthermore, they offer a methodological blueprint for analogous global studies and provide vital theoretical insights for the broader scientific investigation of marine ICH.

Based on the aforementioned empirical findings, this study offers profound practical implications for the spatial governance and conservation planning of ICH in Southeast Coastal China. Currently, ICH protection practices in China are predominantly governed by isolated administrative jurisdictions, such as provinces or municipalities⁴. This administratively driven management paradigm artificially fragments the spatial integrity and historical continuity of the foundational cultural ecosystems that sustain ICH. Consequently, we advocate for a strategic paradigm shift in ICH conservation toward a framework rooted in cultural basins and land-sea coordination. Specifically, by leveraging core nodes such as Guangzhou, Fuzhou, and Quanzhou, policymakers could construct a trans-provincial Maritime Silk Road ICH Corridor encompassing Fujian, Guangdong, and Guangxi. Furthermore, in response to the synergistic enhancement effect generated by the profound spatial congruence of water networks and dialect zones, cross-regional dialect culture demonstration zones must be established to safeguard the underlying regional cultural ecosystems vital for the continuous transmission of ICH.

Although this study systematically elucidates the spatiotemporal evolutionary patterns and underlying driving mechanisms of marine ICH in Southeast Coastal China, thereby providing novel theoretical insights and a quantitative basis for regional ICH research and conservation practices, it still presents four primary limitations.

First, by relying primarily on national and provincial ICH inventory data, this research does not encompass municipal and county-level ICH items. Such data constraints may inadvertently omit ICH elements of substantial latent value, consequently precluding a fully exhaustive representation of the overall spatial distribution pattern of ICH in Southeast Coastal China.

Second, regarding the Geodetector analysis, although this study constructs an indicator system comprising sixteen variables, certain cultural and historical factors were excluded due to profound difficulties in data acquisition. Crucial elements such as religious influences, historical demographic migration trajectories, and ethnic minority settlements currently lack the continuous, high-resolution spatial data requisite for robust quantitative spatial modeling. Specifically, concerning religious impacts, there is a distinct absence of quantified data regarding the spatial networks of temples in Fujian Province and the distribution of Mazu worship to adequately measure their influence on ICH. Regarding historical migration trajectories, epochal events such as the southward demographic shifts during the Tang and Song dynasties, alongside Hakka migrations, lack detailed and continuous spatial documentation. Similarly, precise data delineating the settlement boundaries of ethnic minority groups, such as the She, Hui, and Zhuang populations, remain unavailable. Future research must leverage multi-source data to meticulously quantify these historical and cultural variables, thereby refining the spatial driving factor system for ICH.

Third, concerning interaction detection, this study solely executed analyses on bivariate factor interactions; subsequent research should advance to investigate higher-order multifactorial effects.

Finally, given the regional heterogeneity inherent in ICH, future studies ought to expand the spatial scope to comparatively analyze the divergent ICH systems between northern and southern China. Such comparative endeavors will provide a more profoundly solid theoretical foundation for establishing a highly precise ICH conservation and transmission framework.