Research area
The Yellow River–Yangtze River basin runs through eastern and western China, and abundant water energy resources provide convenient natural conditions for the generation and dissemination of intangible cultural heritage. "The Yellow River–Yangtze Civilization Corridor" is an academic concept proposed by Chinese scholar Cheng Jincheng [45]. It is believed that the river civilization corridor is mainly composed of two corridors, the Yellow River Basin Corridor and the Yangtze River Basin Corridor, and is a self-contained and complete geographical region [38]. This study accepts the division of the Yellow River Basin and the Yangtze River Basin determined by Liu Zhicai as standard [46], as this interpretation is currently widely recognized [47–49]. The River Civilization Corridor in this study covers 18 provinces and cities, including 9 in the Yellow River basin, comprising Shandong, Henan, Shanxi, Inner Mongolia, Shaanxi, Ningxia, Sichuan, Gansu and Qinghai, and 11 in the Yangtze River basin, including Shanghai, Jiangsu, Anhui, Jiangxi, Hubei, Hunan, Chongqing, Sichuan, Yunnan, Qinghai and Tibet. Among these locations, Qinghai and Sichuan are overlapping areas of the two watersheds, so the study scope is combined (Fig. 1).
Data source
This study adopts a broad definition of music, which includes vocal music, dance, drama, and quyi [24]. According to the 10 classification standards of China's intangible cultural heritage, we divide ICHMs into four categories: traditional music, traditional dance, traditional drama and quyi. The national ICHMs data from the "Yellow River–Yangtze River Civilization Corridor" are from the China Intangible Cultural Heritage Network (http://www.ihchina.cn). The provincial ICHM data are from provincial intangible cultural heritage centres. As of December 31, 2022, there were a total of 3,277 ICHMs, including 872 national-level ICHMs and 2,405 provincial-level ICHMs. The coordinate picking tool from Baidu was used to locate the spatial location of each intangible cultural heritage point. The base map was made by using the standard map downloaded from the national basic geographic information system database. For period divisions, based on the research achievements of Tian Xiaobo, Yue Ju and others [50, 51], the historical period of ICHMs is divided into the prehistoric period, pre-Qin period, Qin and Han Dynasties, Wei, Jin, Southern and Northern Dynasties, Sui, Tang and Five Dynasties, Song and Yuan Dynasties, Ming and Qing Dynasties, and modern times. In terms of influencing factors, elevation and slope data were mainly derived from the Geospatial Data Cloud website (https://www.gscloud.cn/). The indices of rainfall and average temperature were derived from the website of Resources and Environmental Sciences and Data Center of Chinese Academy of Sciences (https://www.resdc.cn/). River and transportation data are sourced from the latest vector data provided by Open Street Map and Bigemap. Regional population, GDP, urbanization, etc., are mainly sourced from the China Statistical Yearbook (2022) and the Regional Economic Statistical Yearbook (2022).
Research methods
The nearest neighbour index
The nearest neighbour index is an index used to judge the degree of proximity of ICHM elements in the "Yellow River–Yangtze River Civilization Corridor". The nearest neighbour index is obtained by comparing the ratio of the average nearest distance between ICHMs points to the average distance under a theoretical random distribution. The calculation formula is as follows [52]:
where R is the nearest neighbour distance index and r is the average actual nearest neighbour distance between ICHM points. r1 is the theoretical nearest neighbour distance between ICHM points. n is the number of ICHM points, and s is the area of the area. When R < 1, ICHM points are aggregation-random. When R = 1, the ICHM points are randomly distributed. When R > 1, the ICHM points are uniformly distributed.
Kernel density estimation
Nuclear density analysis is commonly used to calculate the density of point-like elements in the surrounding neighbourhood of a point [53], which can clearly reflect the dispersion and aggregation of ICHM elements. The higher the nuclear density value f (x), the denser the point-like elements. The calculation formula is as follows [54]:
\({ f}_{n}\left(x\right)=\frac{1}{nh}\sum _{i=1}^{n}k\left(\frac{x-{X}_{i}}{h}\right)\) (2)In the formula, k (x) is the kernel function, h > 0 is the search radius, and x-Xi represents the distance from the estimate point x to the sample point Xi.
Standard deviation ellipse
The standard deviation ellipse analysis takes the standard deviation and average centre of the x-axis and y-axis as the basic parameters. It is a quantitative method for analysis of the central trend and transformation direction of geographic feature space. The calculation formula is as follows [55]:
\(\text{x}=\frac{\sum _{i=1}^{n}{x}_{i}}{\text{n}}\) \(\text{Y}=\frac{\sum _{i=1}^{n}{y}_{i}}{\text{n}}\) (3)
In the formula, xi and yi represent the coordinates of the distribution of ICHM points, and n is the total number of ICHM points in a certain period.
Geographical detector
Geographic detectors are a new statistical method to detect spatial differentiation and reveal the driving factors behind it [56, 57].
(1)Factor detection. Factor detection is the detection of the extent to which Factor X explains the spatial variation of the variable Y. The q value is used to indicate its degree. The calculation formula is as follows [58]:
$$q=\left(N{{\sigma }}^{2}-\sum _{h=1}^{L}{N}_{h}{{\sigma }}_{h}^{2}\right)/N{{\sigma }}^{2}$$
4
In the formula, N and σ2 are the sample size and variance, respectively. Nh and \({{\sigma }}_{\text{h}}^{2}\) are the sample size and variance of class h influencing factors. L is the classified number of the influencing factors of class h. The value of q is [0,1], and the larger the value, the stronger the explanatory power of the index to the spatial distribution of ICHMs [59].
(2)Interaction detection. Interaction detection is used to detect whether the influence from Factors X1 and X2 will increase or decrease the density of geographical features after their interaction. There are five main types of results: nonlinear weakening, unilinear weakening, bilinear enhancement, mutual independence, and nonlinear enhancement (Table 1) [56].
Table 1 Interaction probe types
Basis of judgment
|
Interaction detection
|
q( X1∩X2 ) < Min( q( X1 ) ,q( X2 ) )
|
Nonlinear weakening
|
Min( q( X1 ) ,q( X2 ) ) < q( X1∩X2 ) < Max( q( X1 ) ,q( X2 ) )
|
Unilinear weakening
|
q( X1∩X2 ) > Max( q( X1 ) ,q( X2 ) )
|
Bilinear enhancement
|
q( X1∩X2 ) = q( X1 ) + q( X2 )
|
Mutual independence
|
q( X1∩X2 ) > q( X1 ) + q( X2 )
|
Nonlinear enhancement
|
Spatial and temporal distribution pattern of ICHMs in the "Yellow River–Yangtze River Civilization Corridor"
Scale of ICHMs
According to the division standard of China's national geographical regions, the "Yellow River–Yangtze River Civilization Corridor" is divided into three different geographical regions: The east, the middle and the west. The statistics of the number of ICHM projects in the three regions of the corridor are shown in Table 2. On a regional scale, the central region (Henan, Shanxi, Inner Mongolia, Hubei, Hunan, Jiangxi, Anhui) has the largest number of ICHMs, with a total of 1462 items, accounting for 44.61% of the total in the corridor. The western region (Tibet, Qinghai, Gansu, Ningxia, Shaanxi, Sichuan, Yunnan, Chongqing) takes second place, with a total of 1371 items, accounting for 41.84% of total ICHMs in the corridor. The eastern region (Shandong, Jiangsu, and Shanghai) has the smallest number of ICHMs, with only 444 items, accounting for 13.55% of the total in the corridor. In terms of watershed zone, the Yellow River Basin has a large number of ICHMs, with a total of 1777 items, accounting for 54.23%. The number of ICHMs in the Yangtze River Basin ranks second, with a total of 1500 items, accounting for 45.77%. At the provincial level, Henan has the highest number of ICHMs (326 items), accounting for 9.95%, and Sichuan, Shandong, and Shanxi have a large number of ICHMs, accounting for 8.54%, 8.33%, and 7.75%, respectively. Yunnan, Chongqing, Jiangxi, Hubei, and Shaanxi take second place, accounting for 6.71%, 6.62%, 6.59%, 6.59%, and 6.19%, respectively. Ningxia (21) and Shanghai (41) have the fewest ICHMs, accounting for 0.64% and 1.25%, respectively.
Table 2
Types and proportion of ICHM in the “Yellow River—Yangtze River Civilization Corridor”
region
|
Provinces and municipalities (autonomous regions)
|
Traditional music
|
Traditional dance
|
Traditional drama
|
Quyi
|
Total
|
Proportion
|
West
|
Qinghai
|
32
|
30
|
13
|
9
|
84
|
2.56
|
Gansu
|
56
|
59
|
40
|
26
|
181
|
5.52
|
Ningxia
|
7
|
7
|
5
|
2
|
21
|
0.64
|
Shaanxi
|
55
|
74
|
44
|
30
|
203
|
6.19
|
Tibet
|
31
|
112
|
13
|
9
|
165
|
5.04
|
Yunnan
|
89
|
94
|
25
|
12
|
220
|
6.71
|
Sichuan
|
135
|
86
|
33
|
26
|
280
|
8.54
|
Chongqing
|
105
|
58
|
31
|
23
|
217
|
6.62
|
Middle
|
Inner Mongolia
|
90
|
31
|
19
|
15
|
155
|
4.73
|
Shanxi
|
64
|
78
|
73
|
39
|
254
|
7.75
|
Henan
|
64
|
105
|
111
|
46
|
326
|
9.95
|
Anhui
|
38
|
52
|
32
|
29
|
151
|
4.61
|
Hubei
|
70
|
51
|
52
|
43
|
216
|
6.59
|
Hunan
|
38
|
37
|
50
|
19
|
144
|
4.39
|
Jiangxi
|
48
|
92
|
54
|
22
|
216
|
6.59
|
East
|
Shandong
|
62
|
82
|
75
|
54
|
273
|
8.33
|
Jiangsu
|
33
|
30
|
44
|
23
|
130
|
3.97
|
Shanghai
|
15
|
10
|
10
|
6
|
41
|
1.25
|
Type structure of ICHMs
We further calculate statistics on the number of ICHMs in the "Yellow River–Yangtze River Civilization Corridor" from the perspective of type. Overall, traditional dance and music are abundant (with quantities of 1088 and 1032, accounting for 33.20% and 31.49%, respectively). Traditional dramas are relatively few (with a quantity of 724, accounting for 22.09%). Quyi is the least varied (with a quantity of 433, accounting for 13.21%). In terms of region, traditional dance is the most common ICHM in the western and central regions, with 520 and 446, respectively, accounting for 37.93% and 30.51%. Traditional drama (129 items) is the most common ICHM in the eastern region, accounting for 29.05%. Quyi is still the least common ICHM in the three regions, accounting for 9.99%, 14.57%, and 18.69%, respectively. In terms of watershed zone, traditional music is the most abundant type of ICHM in the Yellow River Basin, with a total of 565 items, accounting for 31.80%. The Yangtze River Basin has the highest number of traditional dances, with a total of 536 items, accounting for 35.73%. Quyi remains the least abundant ICHM in the two watersheds, accounting for 13.9% and 12.40%, respectively. At the provincial level, traditional music (135 items) is the most varied in Sichuan, accounting for 13.08%. Traditional dance has the greatest variation in Tibet, with 112 items, accounting for 10.29%. Henan has the highest number of traditional dramas (111 items), accounting for 15.33%. Quyi has the highest number in Shandong, with 54 items, accounting for 12.47%.
Spatial Distribution Pattern of ICHMs
Spatial distribution type characteristics
To better illustrate the spatial agglomeration characteristics of ICHMs in the "Yellow River–Yangtze River Civilization Corridor", the nearest neighbour index (Table 3) is obtained by calculating and processing all ICHMs and their various types in the corridor using the average nearest neighbour in the ArcGIS spatial statistics tool according to the calculation for the nearest neighbour index. The results show that the nearest neighbour index of ICHMs in the corridor is 0.17, and the P value is 0, indicating that the distribution of ICHMs in the basin is strongly agglomerated. The nearest neighbour index of different types of intangible musical heritage ranges from 0.35 to 0.46, and the spatial distribution pattern shows the characteristics of agglomeration.
Table 3
Nearest neighbor index of ICHM in the “Yellow River—Yangtze River Civilization Corridor”
Types
|
Total
|
Traditional music
|
Traditional dance
|
Traditional drama
|
Quyi
|
R
|
0.17
|
0.37
|
0.35
|
0.43
|
0.46
|
P
|
0.000
|
0.000
|
0.000
|
0.000
|
0.000
|
Distribution types
|
agglomeration
|
agglomeration
|
agglomeration
|
agglomeration
|
agglomeration
|
Spatial density distribution characteristics
In this study, the nuclear density analysis tool in ArcGIS is used to estimate the spatial distribution density of ICHMs in the "Yellow River–Yangtze River Civilization Corridor". We further explain the intensity of different intangible musical heritage types in different regions of the corridor. At the same time, the density distribution of ICHM nuclei in the corridor was visualized. The results are shown in Fig. 2 and Fig. 3.
Overall distribution characteristics
From the overall nuclear density map, ICHMs are more abundant in the middle east and less abundant in the west in the corridor, and continuous distribution. A pattern of "one area with multiple points" has been formed. The "one zone" refers to the high-density core area of ICHMs located in the central and eastern regions of the Yellow River Basin, consisting of west Shandong, north Henan, south Shanxi and central Shaanxi. The "four points" refer to the provinces of Jiangsu, Jiangxi, Hubei and Chongqing along the Yangtze River from east to west. In addition, three core areas with lesser density have been formed, from east to west, namely, central Sichuan, eastern Qinghai and southern Tibet. The central and eastern regions are mostly plains with superior natural conditions, which are conducive to the spread and integration of culture and makes it easy for people to gather. The western region is located on the plateau in a desert area and has poor natural conditions, a low level of social and economic development, and a relatively sparse population, which are not conducive to the spread of ICHMs. In addition, as Shaanxi, Shanxi, Henan, Shandong and other provinces are located in the hinterland, they are important birthplaces of Chinese history and culture. The profound cultural heritage and similar cultural background have promoted the exchange and dissemination of ICHMs, thus forming an integrated core area.
Distribution characteristics of different types
According to the density map of different types of nuclei, each type has varying degrees of aggregation. Traditional music heritage is dense in the central and eastern regions and sparse in the western regions, forming a distribution structure of "two cores and two belts" (Fig. 3a). There are two high-density core areas at the border between northwest Henan and southeast Shanxi, as well as in Chongqing and southwest Hubei. The two belts include the weak east‒west belt in the Yellow River Basin formed by the five provinces of Shandong-Henan-Shanxi-Shaanxi-Gansu and the weak east‒west belt in the Yangtze River basin formed by the eight provinces and cities of Shanghai-Jiangsu-Anhui-Hubei -Chongqing-Sichuan-Yunnan. Traditional music is the ICHM that is best at expressing human emotions. Due to the highly developed river transportation system in Henan, Shanxi, Sichuan Chongqing, Hubei and other regions, a large amount of labour music has been produced, such as Yellow River chants, Weifeng gongs and drums, Chuanjiang chants, Longgupo lifting chants, and Yangtze River Xiajiang chants. These are the songs produced and disseminated by the working people in long-term shipbuilding work. In addition, the core areas of ICHMs are located in mountainous areas. High-pitched and bright folk songs have become an important vehicle of emotional expression for people who work in the mountains and for young men and women, resulting in a large number of folk songs, such as Xiling folk songs, Xingshan folk songs, Mashan folk songs, and Mudong folk songs.
Traditional dance shows the characteristic of multicore spatial distribution. It has formed three high-density core areas: west Shandong-north Henan-south Shanxi, central Jiangxi, and Chongqing-southwest Hubei, and two core areas with lesser density: the junction of east Anhui - southwest Jiangsu and north Tibet (Fig. 3b). The main functions of traditional Chinese dance are sacrifice and entertainment. Many traditional dances are distributed in the cradle of Chinese civilization (Shaanxi, Shanxi, Henan, Shandong). Due to the needs of historical rulers, royal sacrificial activities were often held in these areas, which promoted the production and spread of traditional dances. The dense areas of traditional dance that formed in Jiangxi, Hubei, Chongqing, Sichuan, and Tibet may be related to the needs of ethnic minorities to worship gods and their ability to sing and dance.
Traditional drama is the most concentrated ICHM type in the corridor, forming a continuous high-density core area in western Shandong - northern Henan - southern Shanxi - central Shaanxi (Fig. 3c), while other regions have not yet formed high-density areas. Chinese traditional drama developed during the pre-Qin to Tang dynasties and flourished in the Ming and Qing dynasties. During the Ming and Qing dynasties, with the development of the commodity economy, the civil class gradually grew. With the emergence of a large number of consumer groups, art has gradually become popular. Thus, came into being Henan drama, Qu drama, Yue Tune (Henan), Lv drama, Shandong Clapper drama (Shandong), Pu drama, Jin drama, North Road Clapper drama (Shanxi) and Shaanxi Guanzhong Daoqing, Ankang music and other operas. These types of opera continue to grow and influence each other, resulting in a high-density core area of traditional opera.
Quyi has the lowest quantity and a relatively concentrated distribution, with more in the central and eastern regions and fewer in the western regions. It is dispersed in a distribution of "three points in one area" (Fig. 3d). The first district refers to the core area of the Jiangsu-Shandong-Anhui-Henan-Hubei-Shanxi-Shaanxi contiguous area, and the three points include southwestern Hubei, southwestern Chongqing, and central Sichuan. Other areas have not yet formed dense regions. In addition, many cities do not have quyi. Quyi came into being late, but the performance conditions are not highly demanding, and the content is rich and colourful, which is welcomed by the general public. Therefore, although the quantity is limited, it is easier to spread and form dense distribution areas.
Time series pattern of ICHMs
Scale and type structure
"Yellow River – Yangtze River Civilization Corridor" ICHMs have a huge time span. From ancient times to the present day, these traditions cover approximately 3 million years of history. From the perspective of quantitative change, the distribution of ICHMs along the corridor in various historical periods is uneven and fluctuates greatly (Table 4). Overall, the ICHMs are distributed with a characteristic of "two peaks and three valleys", reaching one peak during the pre-Qin to Qin and Han dynasties, and another during the Song, Yuan, and Ming and Qing dynasties. Especially during the peak period of the Ming and Qing dynasties, the number of ICHMs accounted for 57.83% of the total. The lowest points for quantity of ICHMs were in the prehistoric period, the Wei, Jin, Northern and Southern dynasties, and in modern times. The overall quantity gradually increased after two fluctuations of first increasing and then decreasing. The number of ICHMs is greatly influenced by social productivity and people's spiritual and cultural needs. With the continuous improvement of social development and living conditions and people's increasing spiritual needs, the closer to today that the period under examination is in history, the more ICHMs there are.
Table 4
Number of "Yellow River-Yangtze River civilization Corridor" ICHM in different historical periods
ICHM
|
Prehistoric(item /%)
|
Pre-qin(item /%)
|
Qin and Han(item /%)
|
Wei, Jin, Southern and Northern(item /%)
|
Sui, Tang and Five(item /%)
|
Song and Yuan(item /%)
|
Ming and Qing(item /%)
|
modern times(item /%)
|
Traditional music
|
35/41.67
|
91/67.41
|
63/37.95
|
35/72.92
|
117/36
|
148/37
|
352/20.87
|
23/31.94
|
Traditional dance
|
43/51.19
|
25/18.52
|
69/41.57
|
11/22.92
|
123/37.85
|
150/37.5
|
518/30.71
|
19/26.39
|
Traditional drama
|
4/4.76
|
7/5.19
|
31/18.67
|
2/4.17
|
46/14.15
|
43/10.75
|
540/32.01
|
17/23.61
|
Quyi
|
2/2.38
|
12/8.89
|
3/1.81
|
0/0
|
39/12
|
59/14.75
|
277/16.42
|
13/18.06
|
The prehistoric period is the longest time span among the eight historical periods. There were 84 ICHMs in this period, accounting for 2.88% of the total. Traditional dance (43 items) was the most common, followed by traditional music (35 items), and traditional drama (4 items) and quyi (2 items) were the least common. From an examination of spatial distribution, the overall trend shows that there are more traditions in the central part and fewer in the eastern and western parts (Fig. 4a). ICHMs are mainly concentrated in two core areas. One is the border of Chongqing, Hubei and Hunan provinces, and the other is central Sichuan. In addition, a lower density core area has been formed in central Shaanxi. In prehistoric times, due to the poor natural conditions and extremely low productivity, the ancestors were influenced by the thought of nature worship and often worshipped the gods through traditional dances to seek shelter. Therefore, the prehistoric period had the largest number of traditional dances. Since ancient times, Chongqing, Hubei, Hunan and Sichuan have had fertile land and abundant rainfall, which are suitable for planting and conducive to the production and life of the ancestors, so it is easy to form a dense distribution area of ICHMs.
There were 135 ICHMs in the pre-Qin period, accounting for 4.63% of the total. Among them, traditional music accounted for the absolute majority, with 91 items accounting for 67.4%, traditional dance accounted for 25 items, quyi accounted for 12 items, and traditional drama accounted for 7 items. From the perspective of its spatial distribution, ICHMs of this period are mainly concentrated in the three provinces of central Shaanxi, central eastern Shanxi, and north Henan, and the junction of central Hubei and northern Hunan. In addition, two lower density core areas were formed in south Chongqing and northwest Jiangsu (Fig. 4b). In the pre-Qin period, a hundred schools of thought contended. The "Shi" nationality among the nobility began to receive education in the "six arts" (etiquette, music, archery, driving, calligraphy, arithmetic); Confucianism, Taoism, Legalism, Mohism and other schools began to attach importance to the elaboration of musical aesthetics, thus producing a large amount of n traditional music creation. During this period, the core areas of ICHMs were located in the five powerful vassal states of China, namely, Qin (now Shaanxi), Jin (now Shanxi), Chu (now Hubei, Hunan), Wei, and South Korea (now Henan).
During the Qin and Han dynasties, there were 166 ICHMs, accounting for 5.69% of the total. The main ICHMs are traditional dance (69 items) and traditional music (63 items), followed by traditional drama (31 items), and the least common is quyi (3 items). In this period, ICHMs formed a large-scale continuous core area composed of Henan, Shanxi, Gansu, Sichuan and Chongqing and then spread outwards, reflecting the characteristics of the core-edge diffusion pattern of early civilization (Fig. 4c). Qin destroyed the six states and unified China, establishing a unified central country. The state has established the Yuefu system, in which specialized institutions are responsible for collecting, sorting out, creating and performing Folk music and dance. This system has promoted the development of traditional dance and music.
During the Wei, Jin, Northern and Southern dynasties, there were only 48 ICHMs, accounting for 1.64% of the total. Among them, traditional music accounts for the absolute majority, accounting for 72.92% of the total for that time, followed by traditional dance (11 items), and the least varied is traditional drama (2 items), with no quyi. From the perspective of spatial distribution, multiple high-density core areas formed in Jiangsu, Hubei-Hunan-Chongqing, Central Shaanxi-Shanxi-Inner Mongolia-north Henan, Central Sichuan, central Gansu (Lanzhou), northwest Gansu, and central Tibet (Lhasa) (Fig. 4d). During this period, the situation was turbulent, wars were frequent, and the inheritance of some ICHMs was interrupted, resulting in a great reduction in the number of ICHMs compared with the previous period. However, there was a great integration of ethnic groups during this period. Buddhism and Taoism flourished, resulting in the generation and inheritance of numerous religious songs, thus forming multiple distribution points.
During the Sui, Tang, and Five Dynasties periods, the number of ICHMs rapidly increased, totalling 325 items, accounting for 11.14% of the total. Among them, traditional dance had the most items (123 items), traditional music had many items (117 items), and traditional drama and quyi had fewer items (46 items and 39 items). From the perspective of their spatial distribution, ICHMs are concentrated in northern Henan - southern Shanxi - southern Shaanxi - most of Chongqing - northeast corner of Sichuan - northwest Hubei and the northern corner of Hunan, forming a belt core area. In addition, there are two secondary core regions with one on the border between south Anhui and northwest Jiangxi and another in central Tibet (Lhasa). As a whole, it presents a spatial pattern of continuous distribution with more traditions condensed in the middle regions and fewer in the east and west (Fig. 4e). In the Sui and Tang dynasties, the country enjoyed a long period of peace and stability; the rulers were open to the outside world. People from the north moved to the south, social and economic activities were active, and culture and entertainment were abundant. This led to a new peak in the number and distribution of traditional dance and ICHMs, reflecting the general pattern for distribution in ICHMs during the peak of feudal society.
In the Song and Yuan Dynasties, there were 400 ICHMs, accounting for 13.71% of the total. Among them, traditional dance and traditional music have the largest number of ICHMs, 150 and 148, respectively. Compared with the previous era, the number of quyi increased significantly, and the number of traditional dramas is the smallest, accounting for only 10.75 percent of the total. From the perspective of spatial distribution, ICHMs formed four high-density core areas, which were distributed at the border between northwest Shandong and northeast Henan, Jiangxi, southeast Sichuan and northwest Chongqing, and the border between central and western Gansu and eastern Qinghai (Fig. 4f). In the Song and Yuan Dynasties, the art of Song Ci and Yuan Qu (song) reached its peak. There are countless connections between the art of Song Ci and Yuan Qu (song) and quyi, which influence and promote each other. Therefore, the number of quyi types increased during this period. During this period, multiple national regimes were established, and regional political and cultural centres were dispersed. ICHMs formed multiple densely distributed areas and shifted to the southeast.
The number of ICHMs during the Ming and Qing dynasties reached its second peak, with 1687 items, accounting for 57.83% of the total. Traditional drama and traditional dance accounted for 540 and 518, respectively, 32.01% and 30.71% of the total of the era, followed by traditional music (352), and quyi was the least common. In this period, ICHMs formed a continuous distribution in the core area, namely, northwest Jiangsu-north Anhui-west Shandong-northeast Henan-southwest Jin. In addition, the distribution is relatively dense in central Jiangxi and northwest Chongqing. The overall spatial pattern is more focused in the east and distributed less densely in the west (Fig. 4g). During the Ming and Qing dynasties, culture flourished, and entertainment activities were rich and diverse. The five major Chinese drama genres, including Yue drama, Huangmei drama, Pingju, and Yu drama, reached their peak. Traditional dance underwent unprecedented development and became a higher spiritual pursuit in people's daily lives.
In modern times, the number of ICHMs has sharply decreased to only 72, accounting for only 2.47% of the total. The number of ICHMs is relatively evenly distributed across the four categories of musical traditions, and the number of traditional music practices is the largest (23), followed by the number of traditional dance schools (19), traditional drama types (17), and the number of quyi types (13). In this period, the distribution of ICHMs was very concentrated, and a large contiguous core area was formed in Jiangsu-Shandong-Henan-Anhui-Jiangxi-Hubei-Shanxi-Shaanxi-Gansu-Ningxia, showing the characteristics of agglomeration as a whole (Fig. 4h). In modern times, due to the political divisions created by warlords and frequent wars, the protection and inheritance of ICHMs have been adversely affected, so the number has been reduced.
Changes to the centre of gravity
Through the standard deviation ellipse analysis, in general, the "Yellow River – Yangtze River Civilization Corridor" ICHMs over 8 historial periods present a northeast‒southwest - northwest - south - northeast - southeast - south "turning to southeast" trend(Fig. 5). The centre of gravity of the standard deviation ellipse of ICHMs is located in Yunyang District, Shiyan City, Hubei Province (32.815° N, 110.614° E), 911.89 km east of the geometric centre of gravity of the geography of China (36.03° N, 103.40° E). From the point of view of different periods, the centroid of ICHMs in the prehistoric period was in Dianjiang County, Chongqing (30.315°N, 107.571°E); in the pre-Qin period, it moved northeast to Yunyang District, Shiyan City, Hubei Province (32.607°N, 110.305°E). In the Qin and Han Dynasties, it was transferred to Zhuxi County, Shiyan City, Hubei Province (32.326°N, 32.326°N, 32.30°N). 109.517°E). In the Wei, Jin and Southern and Northern Dynasties, the centroid moved northwest to Zhouzhi County, Xi 'an City, Shaanxi Province (33.86°N, 107.737°E). In the Sui, Tang and Five Dynasties period, the centroid moved south to Wanyuan City, Dazhou City, Sichuan Province (32.04°N, 107.889°E). In the Song and Yuan dynasties, it moved northeast to Shangzhou District, Shangluo City, Shaanxi Province (33.677°N, 109.802°E). In the Ming and Qing Dynasties, it continued to move southeast to Neixiang County, Nanyang City, Henan Province (32.933°N, 111.652°E). In modern times, it moved south to Dengzhou City, Nanyang City, Henan Province (32.559°N, 111.805°E). The centre of gravity shifted 554.17 km over the eight periods. Overall, after the Sui and Tang dynasties, the centroid of the ICHMs of the "Yellow River-Yangtze River Civilization Corridor" gradually shifted to the southeast. This may be related to the fact that southern China's economy, culture, politics, military and other aspects began to gradually surpass those of the north. The economic centre of gravity gradually shifted to the south. This result is also similar to the evolution of Qin Shu ICH and China's material cultural heritage historically [26, 50].
As shown in Fig. 5, in general, the standard deviation ellipse rotation angle of ICHMs in the "Yellow River – Yangtze River Civilization Corridor" is 68.357°, showing a narrow distribution in the northeast and southwest directions. The ellipse includes ICHMs in Shandong, Henan, Shanxi, Shaanxi, Inner Mongolia, Ningxia, Gansu (Yellow River Basin), as well as Jiangsu, Anhui, Jiangxi, Hubei, Hunan, Chongqing, Sichuan (Yangtze River Basin) and other provinces. From the perspective of different periods, the ICHM space in prehistoric times presents an east‒west pattern, with an elliptical rotation angle of 87.013°. From the pre-Qin period to the Qin and Han dynasties, the rotation angle changed to the southeast and northwest pattern, and the rotation angle first weakened and then strengthened, rising from 62.63° to 69.677°. From the Wei, Jin, Southern and Northern Dynasties to the Sui, Tang and Five Dynasties, the rotation angle returned to the east‒west pattern, which first strengthened and then weakened, from 84.794° to 82.594°. After the Song and Yuan dynasties, it changed to the southeast and northwest pattern again, and the rotation angle first weakened and then strengthened, rising from 57.037° to 65.994°. Across this historical period from the Sui, Tang, and Five Dynasties period to the Song and Yuan dynasties, the rotation angle of the standard deviation ellipse changed the most, reaching 25.557°. The standard deviation ellipse direction for all 8 periods ranged from 57.037° to 87.013°. The trend of changes in the long and short axes of the ellipse is consistent. They all went through a successive process of "growth–decline–growth" before the Qin and Han dynasties, during the Song and Yuan dynasties, and after the Ming and Qing dynasties. It shows that the spatial distribution of ICHMs in the "Yellow River–Yangtze River Civilization Corridor" evolves consistently along the pattern of agglomeration–dispersion–agglomeration.
The influencing factors of ICHM spatial distribution in the "Yellow River–Yangtze River Civilization Corridor"
There is a comprehensive impact from multiple factors, such as the natural environment and socioeconomic factors, on the protection and inheritance of intangible cultural heritage resources [24, 26]. Therefore, this study summarizes the spatial distribution and influencing factors of intangible cultural heritage both domestically and internationally and combines the actual situation of the Yellow River and Yangtze River basins. By using the geographic detector method, 9 factors, including elevation, slope, rainfall, accumulated temperature, river, traffic, population, GDP and urbanization, were selected to analyse the influencing factors of the spatial distribution of ICHMs in the "Yellow River - Yangtze River Civilization Corridor". Geographic detectors perform better in calculating category data than continuous data, so SPSS software was used to perform two-step clustering on the values of the ICHM continuous detection factors of the "Yellow River – Yangtze River Civilization Corridor", which are divided into six or seven categories.
Analysis of influencing factors
Using geographical detector factor detection, we calculated the q value reflecting the influence of each detection factor on the distribution of ICHMs in the corridor (Table 5). Different dimensions and factors have different influences on the spatial distribution of ICHMs in the corridor. The results show that the core factors that dominate the spatial distribution of ICHMs in the corridor are population (0.4747), accumulated temperature ≥ 10℃ (0.4543), GDP (0.4006), elevation (0.3343) and annual rainfall (0.3281). Among dimensions, the natural environment index accounted for 3, and the social economy index accounted for 2, indicating that the distribution of ICHMs in the corridor is the result of the interaction of the natural environment and human activities. People are the direct creators of and participants in culture, and a dense population provides relatively more feasibility for the generation and development of ICHMs in the region. A developed economy can provide better support and conditions for the generation and dissemination of ICHMs. Sufficient heat and abundant precipitation make it more suitable for human life with abundant resources and high material abundance, which is more conducive to the generation and dissemination of ICHMs. In addition, the flat and open terrain of the area is conducive to human interaction and communication and can effectively promote cultural exchange and dissemination. Relatively steep and closed spaces will block the flow and communication of the population.
Table 5
Influencing factors and its determinant values
Dimensionality
|
Evaluation Indicators
|
Value range
|
Data sources
|
q
|
P
|
Natural environment factors
|
Elevation
|
According to DEM elevation, topographic relief is divided into 6 levels
|
ArcGIS
|
0.3343
|
0.000
|
Slope
|
Divide the slope into 7 levels based on the degree of steepness of surface units
|
ArcGIS
|
0.0025
|
0.000
|
Rainfall
|
The annual average precipitation in China is automatically divided into seven levels according to the natural discontinuity point
|
ArcGIS
|
0.3281
|
0.000
|
≥ 10℃ accumulated temperature
|
China ≥ 10℃ accumulated temperature is automatically divided into 7 levels according to the natural discontinuity point
|
ArcGIS
|
0.4543
|
0.000
|
River
|
Automatically divide the total length of the water system (above level 3) into 6 levels based on natural breakpoints
|
Official statistics
|
0.24
|
0.000
|
Socioeconomic factors
|
Traffic
|
The total mileage of railways, highways and inland waterways will be automatically divided into six levels according to natural discontinuity points
|
Official statistics
|
0.1103
|
0.000
|
Population
|
The permanent population is automatically divided into 6 levels according to natural discontinuity points
|
Official statistics
|
0.4747
|
0.000
|
GDP
|
The total GDP is automatically divided into 6 levels according to the natural break point
|
Official statistics
|
0.4006
|
0.000
|
Urbanization
|
The urbanization rate is automatically divided into 6 levels according to the natural break point
|
Official statistics
|
0.1203
|
0.000
|
Detection and analysis of natural environmental factors. The natural environment is closely related to the formation and development of ICHMs. As seen from the results of Table 5, accumulated temperature ≥ 10℃ (0.4543), elevation (0.3343) and annual rainfall (0.3281) are the natural environmental factors with the highest degree of influence on ICHMs of the "Yellow River – Yangtze River Civilization Corridor". The second most influential factor is the river (0.24), and the degree of influence is also relatively high; Slope (0.0025) has the lowest effect.
Detection and analysis of socioeconomic factors was conducted next. Since ICHMs are a product that is created, protected and inherited in the long term by human beings, social and economic behaviours have a great impact on ICHMs. The influence of socioeconomic factors on the spatial distribution of ICHMs in the corridor is in the following order: population > GDP > urbanization > transportation. Of these, population and GDP have the strongest influence on the spatial distribution of ICHMs, with q values of 0.4747 and 0.4006, respectively. The influence of urbanization and transportation is moderate, with q values of 0.1203 and 0.1103, respectively.
Interaction analysis of influencing factors
In reality, the spatial distribution of ICHMs in the "Yellow River – Yangtze River Civilization Corridor" cannot be determined by a single factor or a single dimension. In this study, the interaction of different factors on the spatial distribution of ICHMs in the "Yellow River-Yangtze Civilization Corridor" was detected by the interaction of geographical detectors (Table 6). The results showed that the five natural environmental factors and the four socioeconomic factors all enhanced each other after pairwise interaction; the influence type was mainly two-factor enhancement, followed by nonlinear enhancement, and there were no independent factors.
Table 6
Results of interaction between different influencing factors
Dimensionality
|
Evaluation Indicators
|
Elevation
|
Slope
|
Rainfall
|
≥ 10℃ accumulated temperature
|
River
|
Traffic
|
Population
|
GDP
|
Urbanization
|
Natural environment factors
|
Elevation
|
0.3343
|
|
|
|
|
|
|
|
|
Slope
|
0.4016**
|
0.0025
|
|
|
|
|
|
|
|
Rainfall
|
0.5302
|
0.3840**
|
0.3281
|
|
|
|
|
|
|
≥ 10℃ accumulated temperature
|
0.5164
|
0.5125**
|
0.6115
|
0.4543
|
|
|
|
|
|
River
|
0.51
|
0.249**
|
0.5676
|
0.5475
|
0.24
|
|
|
|
|
Socioeconomic factors
|
Traffic
|
0.4887**
|
0.1604**
|
0.4755**
|
0.5438
|
0.3239
|
0.1103
|
|
|
|
Population
|
0.5414
|
0.5066**
|
0.6284
|
0.5781
|
0.5881
|
0.5657
|
0.4747
|
|
|
GDP
|
0.5017
|
0.4301**
|
0.5978
|
0.5627
|
0.5433
|
0.5105
|
0.5035
|
0.4006
|
|
Urbanization
|
0.4798**
|
0.1318**
|
0.5581**
|
0.5372
|
0.4258**
|
0.3943**
|
0.5353
|
0.5048
|
0.1203
|
Note: ** indicates a nonlinear enhancement relationship, underscores indicate a bilinear enhancement relationship
|
Specifically, for the sets 1) elevation and slope, traffic, and urbanization, 2) slope and annual rainfall, accumulated temperature ≥ 10°C, river, traffic, population, GDP, and urbanization, 3) annual rainfall and traffic, urbanization, 4) river and urbanization, 5) traffic and urbanization, the relationships are nonlinear and mutually enhancing, and the explanatory power after the intersection of these variables is greater than the sum of their individual effects.
Among the natural environmental factors, the interaction between accumulated temperature ≥ 10℃ and annual rainfall is the strongest. This indicates that a relatively temperate climate will be more conducive to the generation and dissemination of ICHMs in abundant areas. Among the social and economic factors, the synergistic effect between population and traffic is the strongest. This indicates that the more densely populated and highly developed, high-traffic areas easily form ICHM agglomerations. In the interaction between natural factors and social factors, the synergistic effect between annual rainfall and population is more significant than other factors. This indicates that the spatial distribution of intangible heritage is denser in regions with more abundant rainfall and a denser population.
Overall, when natural environmental factors and socioeconomic factors play separate roles, the driving force is not as strong as the interaction between the two. Therefore, policymakers guiding the protection and inheritance of ICHMs in the "Yellow River–Yangtze River Civilization Corridor" need to comprehensively consider the role of all impact factors on the spatial distribution of ICHMs in the corridor.