Analyzing Transregional Vernacular Cultural Landscape Security Patterns with a Nature–Culture Lens: A Case Study of the Yangtze River Delta Demonstration Area, China

Abstract

Cultural landscape security is important to national spatial and cultural security. However, compared with the many achievements in the study of ecological security, transregional cultural landscape security research lacks enough attention to match its importance. In the context of advocacy of ‘connecting practices’ between nature and culture in the field of international heritage conservation, this paper developed an approach for constructing transregional vernacular cultural landscape security patterns and identifying the key protected areas. A method is put forward based on the case of the Yangtze River Delta Demonstration Area, one of the fastest urbanizing regions in China, and included the following three steps: (1) analyze the core values of the transregional vernacular cultural landscape from a long-time series and multi-scale perspective; (2) integrate ecological security assessment and value security evaluation by combining qualitative with quantitative methods; (3) build a comprehensive vernacular cultural landscape security pattern to identify key protected areas and develop a zoning and grading conservation strategy toolkit. The results proved that our new method could effectively build a cross-regional network of integrated spatial and functional relationships between the historical cultural and natural landscape and have great significance in improving the level of transregional territorial spatial governance.

1. Introduction

The ideas from Relph’s sense of place, Merleau-Ponty’s phenomenology and Henri Lefebvre’s importance of everyday life inspired J. B. Jackson and D. W. Meinig to focus on the common values of ordinary landscapes [1]. J. B. Jackson linked “Vernacular” with “landscape” in his book Discovering the Vernacular Landscape. Through the comparison of the political landscape and residential landscape, he gave a “vague” concept of vernacular landscape [2]. The vernacular landscape is the product of constant adaptation and conflict. It adapts to the novel and complex natural environment and coordinates the people who have different views on the environmental adaptation mode. It has the obvious characteristics of “grassroots”, “daily”, “mobility”, “temporality” and “adaptability”. The vernacular landscape includes the built environment, agricultural and natural landscapes and the inhabitants [3], and is essentially a cultural landscape [4]. These “every-day or degraded landscapes as well as those that might be considered outstanding” are all important parts of community identity and local culture [5], and are of great significance to local environmental management decision-making and sustainable development.

However, global climate warming and rapid urbanization seriously threaten the safety of the vernacular cultural landscape [6,7]. The key to threatening the safety of the cultural landscape can be understood as the fundamental decoupling of social culture and ecological subsystems in the cultural landscape [8]. The cultural landscape contains rich evidence of our society and history, and it is easy to make viewers associate it with the value of heritage. The heritage landscape includes not only tangible and material things, but also the spiritual inheritance of broader values and customs, which can inspire us to establish links with the “past” and social history, thus forming community values and social identities [9]. Many scholars have tried to conduct corresponding landscape security studies based on ecological theoretical approaches in terms of landscape security patterns [10], ecosystem services [11] and vulnerability assessment [12]. Compared with the booming studies on ecological security patterns [13,14,15], the rare concerns about cultural landscape security pattern research do not match their importance [16]. In recent years, a series of academic studies have been carried out in the field of international heritage around the interrelation of natural and cultural values [17,18]. The clarification of nature–culture keywords such as “biocultural”, “resilience” and “traditional knowledge” also provides a conceptual consensus for the development of a “connecting practice project” [19]. Based on the above concepts, this study attempts to establish a more holistic framework for the security pattern of the vernacular cultural landscape and explore the possibility of applying it in practice.

The area of the Yangtze River Delta is one of the fastest urbanized regions in China. In the context of China’s reform and innovation to explore regional integration, balanced and high-quality development, the Chinese government decided to establish the Yangtze River Delta Ecological and Green Integration Development Demonstration Area (hereinafter referred to as the demonstration area) in 2018. The demonstration area breaks the boundaries of administrative divisions. It takes the new demonstration of world-class quality of human settlements and the new benchmark of eco-green high-quality development as its development vision. There is a wide-area ecological water network connecting many scenic heritage resources and ordinary landscapes, such as the vernacular settlements, characteristic pastoral scenery and agricultural polders, which are steeped in intangible cultural practices such as local traditional scientific knowledge and practical wisdom of resource management [20,21].

However, the previous studies of territorial spatial resource protection always adopt the evaluation system of resources and environmental carrying capacity and spatial suitability, which mainly focus on the value assessment of natural resources and the ecological environment [22,23,24]. The planning practice mainly focuses on simple environmental governance, ecological protection and restoration, and takes it as an effective way to achieve the goal of high-quality ecological green development. Although this resource-oriented mathematical evaluation method guarantees the bottom line of ecological security, it separates culture from nature and ignores the two-way mutual construction, which is an inseparable relationship deeply embedded in the local landscape. Therefore, the correct evaluation of the safety of vernacular cultural resources related to nature is directly related to the ultimate protection efficiency, as well as the harmonious and healthy development of human settlements and ecological space in the region. In addition, under the influence of climate warming and urbanization, the vernacular cultural landscape in the demonstration area faces huge security challenges. This problem and situation is also internationally representative and typical.

Therefore, this study aims to embody the new concept of an ecological green focus and broaden the thinking of environmental resource protection from the perspective of the integrity of the natural cultural ecosystem. The study takes optimizing the safety of the local cultural landscape as an effective way to realize the high-quality development of an ecological green focus. We have established a methodology for the security pattern of the transregional vernacular cultural landscape for multi-dimensional value conservation. Additionally, we chose the demonstration area as the research area to explore the possibility of implementing this approach. The significance of this study is that the key protection areas can be identified by the security pattern classification. It also helps to determine the priority of the protection and management of cross-regional vernacular cultural landscapes. Furthermore, the corresponding requirements for the protection and utilization of land and resources should be formulated in a scientific and reasonable way as a whole.

2. Materials and Methodology

2.1. Study Area

The demonstration area comprises the Qingpu District of Shanghai, the Wujiang District of Suzhou City, Jiangsu Province and Jiashan County of Jiaxing City, Zhejiang Province (Figure 1), with a total area of about 2413 square kilometers.

2.2. Data Sources

The study summarized and collated the relevant data and information in the demonstration area and divided them into two aspects: nature and culture [25,26,27]. Additionally, we adopted GCS_WGS_1984 as a geographical coordinate system and carried out geographical visualization of these data in ArcGIS (

Table 1. Description of the datasets utilized in this study.

Category	Name	Usage	Year	Type	Source
Nature	DEM	Elevation analysis	2020	30 m Geo Tiff	Geospatial Data Cloud (http://www.gscloud.cn/search, accessed on 21 July 2022)
		Slope analysis
		Aspect analysis
		Hydrological analysis
	Soil data	Soil analysis	1995	30 m Geo Tiff	Resource and Environmental Science and Data Center, Chinese Academy of Sciences (https://www.resdc.cn/data.aspx?DATAID=145, accessed on 5 August 2022)
	NDVI	Vegetation cover analysis	2020	250 m Geo Tiff	NASA Earth Observation Data (https://ladsweb.modaps.eosdis.nasa.gov/, accessed on 28 July 2022)
	Master plans	Analysis of the distribution characteristics of important lakes and wetlands	2020	Document	Department of Natural Resources of Zhejiang Province (https://zrzyt.zj.gov.cn/art/2020/6/18/art_1289924_47444338.html, accessed on 25 August 2022)
Culture	Boundary data	Clarify the scope of regional administrative planning	2019	Shape file	National Catalogue Service For Geographic Information (http://www.webmap.cn/main.do?method=index, accessed on 21 July 2022)
	Land cover data	Land use analysis	2020	30 m Geo Tiff	GlobeLand30: Global Geo-information Public Product (http://www.globallandcover.com/, accessed on 21 July 2022)
	Spatial data	Distribution characteristics of natural villages	2015	1:20,000 Shape file	National Bureau of Statistics (http://www.stats.gov.cn/tjsj/tjbz/tjyqhdmhcxhfdm/2015/index.html, accessed on 12 August 2022)
		Distribution characteristics of cultural landscape sites	2021	Shape file	List of Immovable Cultural Heritage in Shanghai List of Cultural Heritage Protection Units at All Levels in Suzhou Classification List of Cultural Heritage Protection Units in Zhejiang Province
	Local chronicles	Historical and geographical changes	/	Historic text	Qingpu (Jiangsu) County Records 1592 Continued Records of Qingpu County, 1934 Jiaxing Prefecture (Zhejiang) Records, 1600, 1722, 1879 Jiaxing Mansion Map, 1597 Gusu County Records, 1506
	Archaeological map			Graphic	Map of Qingpu County, 1862 Military map of Qingpu County, 1909 Map of southern Jiangsu Seawall, 1753 Map of Jiaxing Prefecture, 1879 Map of Jiaxing city, 1917, 1929
	Historical aerial image			Graphic	Satellite images of Zhejiang and Jiangsu, 1960–2019 (http://xzgcl70.tianditu.gov.cn/, accessed on 12 August 2022) Satellite images of Shanghai, 1984–2022 (Google Earth Pro)

).

2.3. Methodology

The framework of constructing transregional vernacular cultural landscape security patterns was divided into three steps: cultural landscape value condensation, transregional cultural landscape security assessment and pattern construction (Figure 2).

2.3.1. Step 1: Concise Cultural Landscape Core Value System

First, based on the various types of natural substrate data of the demonstration area and the understanding of polder types, the whole natural landscape features in the area were refined.

Secondly, we sorted out the historical geographic changes in the transregional landscape by combing through local chronicles, historical maps and other relevant documents. Additionally, we then divided the periods of historical characteristics. After that, the core values of the local cultural landscape in the area were systematically revealed and we identified the value attribute elements. Additionally, according to the dominant attributes, the value attribute elements were divided into three categories [15]: landscape designed and created intentionally by people, organically evolving landscape and associative cultural landscape.

2.3.2. Step 2: Transregional Cultural Landscape Security Assessment

(1) Ecological security assessment

From the perspective of the landscape pattern, the study quantified the loss degree of natural attributes of the regional landscape pattern after being affected by external influences through the landscape disturbance and vulnerability index. It constructed the landscape ecological risk index (ERI) to determine the level of regional ecological security in reverse. The specific calculation formula is as follows:

$${\mathrm{E}\mathrm{R}\mathrm{I}}_{\mathrm{k}}={\sum }_{\mathrm{i}}^{\mathrm{n}}\frac{{\mathrm{A}}_{\mathrm{k}\mathrm{i}}}{{\mathrm{A}}_{\mathrm{k}}}\times {\mathrm{U}}_{\mathrm{i}}\times {\mathrm{V}}_{\mathrm{i}},$$

(1)

where ${\mathrm{E}\mathrm{R}\mathrm{I}}_{\mathrm{k}}$ is the ecological risk index of the kth risk unit; n is the number of landscape types; i is cropland, woodland, grassland and others of the six types of landscape; ${\mathrm{A}}_{\mathrm{k}\mathrm{i}}$ is the area of class i landscape in the kth risk unit (km²); ${\mathrm{A}}_{\mathrm{k}}$ is the total area of the kth risk unit (km²); ${\mathrm{U}}_{\mathrm{i}}$ is the landscape disturbance index of landscape type i; and ${\mathrm{V}}_{\mathrm{i}}$ is the landscape vulnerability index of landscape type i.

Among them, the landscape disturbance index (${\mathrm{U}}_{\mathrm{i}}$) selected the landscape fragmentation index (${\mathrm{C}}_{\mathrm{i}}$) [28,29], landscape separation index (${\mathrm{F}}_{\mathrm{i}}$) [30] and landscape dominance index (${\mathrm{D}}_{\mathrm{i}}$) [31,32], which are closely related to landscape disturbance. The specific expressions and related calculation formulas are shown in

Table 2. The related calculation formulas for landscape disturbance index.

Index	Symbol	Computation	Formula Interpretation
Landscape disturbance	${\mathrm{U}}_{\mathrm{i}}$	${\mathrm{U}}_{\mathrm{i}}=\mathrm{a}\times {\mathrm{C}}_{\mathrm{i}}+\mathrm{b}\times {\mathrm{F}}_{\mathrm{i}}+\mathrm{c}\times {\mathrm{D}}_{\mathrm{i}}$	${\mathrm{C}}_{\mathrm{i}}$ indicates landscape fragmentation index, ${\mathrm{F}}_{\mathrm{i}}$ indicates landscape separation index, ${\mathrm{D}}_{\mathrm{i}}$ indicates landscape dominance index; a, b and c are the weight index, which is assigned to 0.5, 0.3 and 0.2, respectively, according to the previous research [33,34] and the actual situation of the demonstration area.
Landscape fragmentation	${\mathrm{C}}_{\mathrm{i}}$	${\mathrm{C}}_{\mathrm{i}}=\frac{{\mathrm{N}}_{\mathrm{i}}}{{\mathrm{A}}_{\mathrm{i}}}$	${\mathrm{N}}_{\mathrm{i}}$ denotes the number of patches of landscape type i, and ${\mathrm{A}}_{\mathrm{i}}$ denotes the patch area of landscape type i.
Landscape separation	${\mathrm{F}}_{\mathrm{i}}$	${\mathrm{F}}_{\mathrm{i}}=\frac{\surd {\mathrm{S}}_{\mathrm{i}}}{2{\mathrm{P}}_{\mathrm{i}}}$	${\mathrm{S}}_{\mathrm{i}}$ denotes the distance index of landscape type (${\mathrm{S}}_{\mathrm{i}}={\mathrm{N}}_{\mathrm{i}}/\mathrm{A}$), and ${\mathrm{P}}_{\mathrm{i}}$ represents the relative coverage of landscape types (${\mathrm{P}}_{\mathrm{i}}={\mathrm{A}}_{\mathrm{i}}/\mathrm{A}$).
Landscape dominance	${\mathrm{D}}_{\mathrm{i}}$	${\mathrm{D}}_{\mathrm{i}}=\mathrm{d}\times {\mathrm{L}}_{\mathrm{i}}+\mathrm{e}\times {\mathrm{P}}_{\mathrm{i}}$	${\mathrm{L}}_{\mathrm{i}}$ represents the relative density of landscape types (${\mathrm{L}}_{\mathrm{i}}={\mathrm{N}}_{\mathrm{i}}/\mathrm{N}$), and ${\mathrm{P}}_{\mathrm{i}}$ represents the relative coverage of landscape types (${\mathrm{P}}_{\mathrm{i}}={\mathrm{A}}_{\mathrm{i}}/\mathrm{A}$); d and e are weight indices, which are assigned as 0.4 and 0.6 [32].

.

Concerning the relevant literature [35,36] and the region’s current situation, the demonstration area was classified into six types: cropland, woodland, grassland, water, urban land and unused land. Then, it was graded and normalized to produce a landscape vulnerability index ($V_i$). The vulnerability classification of each landscape type was as follows: unused land-6; water-5; cropland-4; grassland-3; woodland-2; urban land-1.

In order to ensure the integrity of the information and the accuracy of the values, the study integrated the foundation of previous studies [37,38] with the number and calculation workload of landscape patches and selected a 1 km × 1 km square grid for equally spaced sampling to obtain a total of 2677 ecological risk units (Figure 3). Furthermore, the results of the landscape ecological risk index were used as the results of the ecological risk calculation for the center points of each unit, and their ecological security levels were determined by spatial interpolation.

(2) Cultural value security assessment

First, the study referred to the relevant documents and literature on the cultural landscape value assessment [39,40,41] and used the Delphi method to clarify the indicator subdivisions under different value orientations regarding value importance and value quality. Considering the value focus of different cultural landscape types, the study applied the AHP method and Yaahp software to calculate each evaluation indicator’s weights and finally established the evaluation system for the cultural value security of the transregional cultural landscape.

Subsequently, based on the above assessment system, the value importance and quality of each value attribute element in the demonstration area were scored separately and then superimposed to determine its cultural landscape value security level, calculated by the following formula.

$${CSV}_i=\frac{100}{0.5({VI}_i+{VQ}_i),}$$

(2)

where ${CSV}_i$ is the cultural value security score of the value attribute element; ${VI}_i$ is the value importance score of the value attribute element; and ${VQ}_i$ is the value quality score of the value attribute element.

Finally, the security values of the value attribute elements (points) were assigned to their surrounding neighborhoods (surfaces) through the kernel density analysis tool in ArcGIS10.6 to visualize the results of the cultural value security assessment and the spatial aggregation of the demonstration area. The specific calculation formula is as follows:

$${KDV}_i=\frac{1}{h^2}{\sum }_{i=1}^n[\frac{3}{\pi }·{CSV}_i{(1-{\left(\frac{d_i}{h}\right)}^2)}^2],$$

(3)

where ${KDV}_i$ is the score estimation of value security in the neighborhood of the value attribute element; i = 1, …, n is the number of value attribute elements; h is the search radius; ${CSV}_i$ is the cultural value security score of the value attribute element; and $d_i$ is the straight line distance between value attribute element i and the center point of domain space.

2.3.3. Step 3: Identify Cultural Landscape Security Pattern and Key Protected Areas

Based on the cultural landscape’s definition of ‘Combined works of nature and humankind’ [42], the ecological security and value security evaluation results were superimposed equivalently through the raster calculator of ArcGIS10.6, and the demonstration area level of the cultural landscape security pattern was divided by an equal interval method. Finally, optimization strategies were developed according to the landscape characteristics of the different hierarchical security patterns.

3. Results

3.1. Condensation of Cultural Landscape Values and Identification of Value Attributes Based on Natural and Historical Geography Analysis

3.1.1. Natural Geography Analysis

Its topography is low in the north, high in the south and slightly inclined to Taihu Lake. Its relative height is less than 25 m (Figure 4a). The terrain fluctuates gently, and the slope change is below five (Figure 4b). Dianshan Lake and Yuandang are the ecological hearts of the demonstration area, and Jiangnan Canal and the Taipu River are vertical and horizontal green corridors. They all structure the water network pattern of the whole site (Figure 4c). The water system has various forms, and the water coverage rate is as high as 20.6% (Figure 4e,f). The soil composition is mainly in paddy and degleyed paddy soil (Figure 4d). Among the land use types, cropland accounts for the highest proportion, accounting for 48.7%, followed by urban land, accounting for 29.3%, and forest and grassland at a smaller scale (Figure 4g), accounting for only 1.4%. A series of human activities, such as building dikes, digging water and building fields, has created a complete cultural ecosystem of the polder system and formed four landscape geographical feature divisions: the Lougang Area, Hudang Area, River Network Area and Great Lakes Area (Figure 4h).

3.1.2. Historical Geography Analysis

The demonstration area has an excellent natural resources endowment, which has laid a good material foundation for developing its cultural resources. Through the crawling and examination of ancient documents and historical maps, we divided the evolution of the demonstration area’s vernacular cultural landscape into four periods: the sprouting period (Neolithic Age to Han Dynasty), the pioneering period (Three Kingdoms to Song Dynasties), the boom period (Yuan, Ming and Qing Dynasties) and the transition period (the Republic of China to the present).

The only type of cultural resource in the sprouting period is the ancient cultural site (Figure 5), which is focused on the higher terrain on the southeast side of the area (Figure 6a). The number of cultural resources in the pioneering period gradually increased, and historical and cultural towns, such as Tongli Town and Zhenze Town, took shape in this period (Figure 6b). During the boom period, cultural resources increased dramatically, distributed in clusters across the study area (Figure 6c). Their types were abundant, and the bridge is the most typical, totaling 68. These cultural resources have directly or indirectly contributed to the formation and development of the ten historical and cultural towns represented by Xitang Ancient Town. The important historical sites and buildings of the modern era were the primary value attribute elements in the transition period, forming a modern water town pattern with alternating old and new things (Figure 6d).

3.1.3. Core Value System and Classification of Value Attribute Elements

The vernacular cultural landscape conforms to the construction logic of the typical residential environment in the Taihu Lake Basin of China. The core value of the demonstration area is a world-class model of waterfront human dwelling civilization, which derived from the joint outcome of the harmonious blue–green spatial system, the charming district with Jiangnan water town culture and the eternal wisdom of water management and agriculture (

Table 3. Core values of the vernacular cultural landscape in the demonstration area.

Core Values of the Vernacular Cultural Landscape in The Demonstration Area	Specific Elaboration of Core Values
Harmonious Blue–Green Spatial System	The area is densely covered with farmland and woodland, with vertical and horizontal water networks, and blue, green and scenery are connected in a series to form a world-class vernacular space model of harmonious coexistence between humans and nature.
Charming District with Jiangnan Water Town Culture	The multi-regional cultures meet in the area, the traditional water towns and villages are densely distributed and the cultural heritage is profound, which embodies the unique historical and humanistic charm of Jiangnan water towns.
Eternal Wisdom of Water Management and Agriculture	After thousands of years of tempering, the hydraulic engineering of polder fields in the area still shows the strong vitality of the wisdom of water management and farming in the southern region of the Yangtze River.

).

Based on the above interpretation of values, the 284 value attribute elements that formed during the four stages of development were identified and classified into three categories: landscape designed and created intentionally by people (229), organically evolving landscape (52) and associative cultural landscape (3) (Figure 7).

3.2. Regional Cultural Landscape Security Assessment Results

3.2.1. Ecological Security Assessment Results

Through Fragstats4.2, the landscape pattern indexes for six land use types were calculated by combining the characteristics of landscape patches (

Table 4. Calculation results of ecological risk index in the demonstration area.

Landscape Type	${\mathbf{A}}_{\mathbf{i}}$	${\mathbf{N}}_{\mathbf{i}}$ (km2)	${\mathbf{C}}_{\mathbf{i}}$	${\mathbf{F}}_{\mathbf{i}}$	${\mathbf{D}}_{\mathbf{i}}$	${\mathbf{U}}_{\mathbf{i}}$	${\mathbf{V}}_{\mathbf{i}}$	${\mathbf{R}}_{\mathbf{i}}$
Cropland	117,665.91	234	0.0019	0.0319	0.4715	0.1048	0.1428	0.015
Woodland	1430.37	65	0.0454	1.3846	0.0115	0.4404	0.2382	0.1049
Grassland	1731.24	20	0.0115	0.6345	0.0207	0.2003	0.1905	0.0381
Unused	60.03	5	0.0833	9.1501	0.0009	2.7869	0.0476	0.1327
Water	49,727.16	581	0.0116	0.1191	0.2138	0.0843	0.0952	0.008
Urban land	70,752.78	1349	0.0191	0.1275	0.2816	0.1041	0.2857	0.0297

). After this, the transregional landscape ecological security assessment results were visualized using Ordinary Kriging in ArcGIS 10.6. The results of the landscape ecological assessment were divided into five levels by the Jenks method: high ecological security, moderate-high ecological security, moderate ecological security, moderate-low ecological security and low ecological security.

As shown in Figure 8, the total proportion of high ecological and moderate-high ecological security areas was 64.66%, and the ecological security situation in the demonstration area was excellent. From the perspective of spatial distribution, the ecological security level in the demonstration area conformed to the terrain change, and the ecological security value in the northwest and central low-lying areas was higher than that in the southeast.

Among them, the land use type of the high ecological security area was mainly water, and the ecological regulation and storage capacity was strong. Thus, the ecological risk index rate was low. The moderate-high ecological security area was uniformly distributed in a continuous pattern, with arable land and widely distributed rivers, and the relationship between water and fields was relatively balanced. Hence, the landscape ecological risk index was low. The moderate ecological security area was mainly evenly distributed irregularly hollow patches, with a tendency to expand and adhere between patches. There might be a risk of encroachment on the high ecological security area. Areas with moderate-low ecological security levels mainly involved Xianghuaqiao Street and Huaxin Town in Qingpu, Wujiang Economic and Technological Development Zone, Shengze Town in Wujiang and Weitang Street in Jiashan. They formed four low ecological security areas. In these areas, both the population and industrial construction activities were concentrated, which are tremendous pressures on ecological environmental protection. Low ecological security areas accounted for a tiny proportion of space, mainly distributed in the core construction areas of Qingpu and sporadically distributed in key development towns in Wujiang. Additionally, this area was significantly affected by human activities, with a high degree of fragmentation of landscape patches and a high degree of ecological risks.

3.2.2. Cultural Value Security Assessment Results

The cultural value security assessment results were divided into two parts. First was the formulation of the assessment indexes and their weighting. The second was the spatial visualization of the value security assessment results.

The assessment indexes of cultural landscape value importance were constructed from five aspects (history, science, art, society and culture) [43,44], four levels (target level, criterion level, domain level and factor level) and 31 evaluation indicators. The scale also complied with the value focus of different cultural landscape subtypes and derived the indicator weights for different subcategories (

Table 5. Assessment scale of cultural landscape value importance in the demonstration area.

Target Layer A	Criterion Layer B	Class B Weight	Domain Layer C	Class C Weight	Factor Layer D	Class D Weight
Value importance evaluation (A1)	Historical value (B1)	DL*-0.2308	Historical accumulation (C1)	DL-0.1667	Age of construction (D1)	DL-0.1667
						EL-0.1667
				EL-0.1667		AL-0.1667
					Protection level (D2)	DL-0.8333
				AL-0.1667		EL-0.8333
						AL-0.8333
		EL*-0.1111	Historical influence (C2)	DL-0.8333	Popularity of relevant historical figures (D3)	DL-0.1429
						EL-0.1429
						AL-0.1429
				EL-0.8333	Influence of relevant historical events (D4)	DL-0.1429
						EL-0.1429
						AL-0.1429
		AL*-0.1086		AL-0.8333	Importance of historical function (D5)	DL-0.7143
						EL-0.7143
						AL-0.7143
	Scientific value (B2)	DL-0.2308	Construction level (C3)	DL-0.1667	Uniqueness of construction skills (D6)	DL-0.3
						EL-0.3
						AL-0.3
					Exquisite degree of building components (D7)	DL-0.3
				EL-0.1667		EL-0.3
						AL-0.3
					Advanced construction skills (D8)	DL-0.3
		EL-0.1111				EL-0.3
				AL-0.1667		AL-0.3
					Scale of the building (group) (D9)	DL-0.1
						EL-0.1
						AL-0.1
			Wisdom of human settlement in the polder system (C4)	DL-0.8333	Typicality of application of local materials (D10)	DL-0.3333
						EL-0.3333
		AL-0.1086				AL-0.3333
				EL-0.8333	Suitability of functional layout conforming to regional space (D11)	DL-0.3333
						EL-0.3333
						AL-0.3333
				AL-0.8333	Building construction technology adapted to climate and environment (D12)	DL-0.3333
						EL-0.3333
						AL-0.3333
	Aesthetic value (B3)	DL-0.2308	External manifestation (C5)	DL-0.1667	Shape gracefulness (D13)	DL-0.125
						EL-0.125
						AL-0.125
					Color harmony (D14)	DL-0.125
				EL-0.1667		EL-0.125
						AL-0.125
					Material adaptability (D15)	DL-0.125
		EL-0.1111				EL-0.125
				AL-0.1667		AL-0.125
					Historical landscape quality (D16)	DL-0.625
						EL-0.625
						AL-0.625
			Artistic connotation (C6)	DL-0.8333	Landscape artistic conception (D17)	DL-0.6
						EL-0.4055
		AL-0.4057				AL-0.4055
				EL-0.8333	Artistic style (D18)	DL-0.2
						EL-0.115
						AL-0.115
				AL-0.8333	Aesthetic potential (D19)	DL-0.2
						EL-0.4796
						AL-0.4796
	Cultural value (B4)	DL-0.2308	Civilization connection (C7)	DL-0.5	Civilization witness (D20)	DL-0.8333
						EL-0.8333
				EL-0.125		AL-0.1667
					Relevance of spiritual belief (D21)	DL-0.1667
				AL-0.5		EL-0.1667
						AL-0.8333
		EL-0.1111	Characteristic inheritance (C8)	DL-0.5	Relevance of traditional folk customs (D22)	DL-0.2
EL-0.2
AL-0.6333
EL-0.875				Inheritance of regional folk culture (D23)	DL-0.2
					EL-0.2
		AL-0.2686			AL-0.2605
AL-0.5				Cultural diversity (D24)	DL-0.6
					EL-0.6
					AL-0.1062
Social value (B5)	DL-0.0769	Social identity (C9)	DL-0.8333	Public participation (D25)	DL-0.4545
					EL-0.4667
					AL-0.4899
			EL-0.1667	Public openness (D26)	DL-0.0909
					EL-0.4667
					AL-0.0594
			AL-0.5	Emotional cohesion (D27)	DL-0.4545
	EL-0.5556				EL-0.4667
					AL-0.4507
		Social security (C10)	DL-0.1667	Tourist attraction (D28)	DL-0.0892
					EL-0.0892
					AL-0.0892
				Industrial promotion (D29)	DL-0.4301
			EL-0.8333		EL-0.4301
	AL-0.1086				AL-0.4301
				Traffic accessibility (D30)	DL-0.0506
					EL-0.0506
			AL-0.5		AL-0.0506
				Educational significance (D31)	DL-0.4301
					EL-0.4301
					AL-0.4301

* DL is an abbreviation for landscapes designed and created intentionally by people, EL is an abbreviation for organically evolving landscapes, AL is an abbreviation for associative cultural landscapes.

).

According to the results of the field research, the application of indigenous knowledge, with the polder system at its core, shaped the vernacular habitat in the demonstration area. It highly integrated agricultural water conservancy, settlement construction, water space and traditional folklore, and transformed the lowland of the lake area with frequent floods into a livable landscape pattern on the polder fields. Therefore, the study followed the definition of authenticity and integrity [43] and established a value quality evaluation system based on the above landscape pattern characteristics. It was specifically concerned about the polder field system, the local built heritage, the water environment and the people involved. Meanwhile, we subdivided 22 sub-indicators from other internal and external factors such as form and design, materials and function, location and environment, scale and area, technology and management systems and cultural spirit and intangible heritage (

Table 6. Assessment scale of cultural landscape value quality in the demonstration area.

Carrier Layer A	Class A Weight	Index Factor Layer B	Class B Weight
Polder system (A1)	0.3125	Scale pattern and patch integration degree of polder system (B1)	0.3333
		Agricultural production organization and agricultural productivity in polder system (B2)	0.3333
		Ecological allocation ability of the polder field mainly based on flood control and drainage and lake water regulation and storage (B3)	0.3333
Local built heritage (A2)	0.0625	Historical features of single vernacular buildings or buildings (B4)	0.25
		Structural integrity of vernacular buildings or buildings (B5)	0.25
		Material authenticity of vernacular architecture monomer or building group (B6)	0.25
		Functional continuity of vernacular architecture monomer or building group (B7)	0.25
Water environment (A3)	0.3125	Openness of water system in surrounding lakes and lakes (B8)	0.1429
		Connectivity of surrounding linear water systems (B9)	0.1429
		Morphological diversity of surrounding water resources (B10)	0.1429
		Water quality of surrounding water resources (B11)	0.1429
		Quantity of surrounding water resources (B12)	0.1429
		Continuity of peripheral water network function (B13)	0.1429
		Perfection degree of peripheral related traditional water resources management system (B14)	0.1429
People involved (A4)	0.3125	Settlement and migration of residents (B15)	0.25
		Inheritance degree of paddy fields farming techniques such as river dredging, flood control and drainage and farmland irrigation (B16)	0.25
		Authenticity of the Wu dialect system used by local or surrounding residents (B17)	0.0833
		Integrity of relevant historical archives (B18)	0.0833
		Integrity of related architectural archives (B19)	0.0833
		Integrity of relevant technical files (B20)	0.0833
		Circulation of related literary works (B21)	0.0833
		Continuity of related folk skills (B22)	0.0833

).

Finally, the study evaluated the value security scores of 284 value attribute elements (Appendix A), which were visualized and classified into five categories: high value security area, moderate-high value security area, moderate value security area, moderate-low value security area and low value security area (Figure 9).

It can be seen from Figure 8 that the overall performance of value security in the demonstration area was excellent, with nearly 85% of the regional space at a high level of value security. Additionally, the southeast region mainly tended to be at a medium-high level of security, which was better than the northwest region.

Among them, the low value security area accounted for the smallest area. It had a scattered layout, involving Tongli Ancient Town, Zhenze Ancient Town, Lili Ancient Town, Xitang Ancient Town and surrounding areas. In this area, value attribute elements were highly clustered. Nevertheless, due to poor protection, there was a severe loss of authenticity and integrity, resulting in a low value security level. The moderate-low value security area was the expansion area of the low value security area, slightly larger in area than the low value security area, and involved two historic towns, Zhujiajiao and Ganyao, in addition to the three ancient towns mentioned above. Moderate value security areas showed the distribution trend of concentrated groups, mainly distributed in the region’s neighborhood space of famous historical and cultural towns and villages. Moderate-high value security areas were distributed contiguously, with a relatively even distribution of value attribute elements and good expression of cultural values. The natural value attribute of the high value security area was prominent, and the number of value attribute elements was small and scattered, which had a low influence on the expression of the demonstration area’s cultural value.

3.3. Identification of Security Patterns in Vernacular Cultural Landscapes and the Formulation of Optimization Strategies for Key Protected Areas

3.3.1. Comprehensive Assessment Results and Security Level Division

In total, there were five levels of vernacular cultural landscape security patterns in the demonstration area: high security area, relative security area, general security area, relative insecurity area and insecurity area (Figure 10).

From Figure 10, the vernacular cultural landscape security level in the demonstration area was generally high, with about 66.51% of the area at a high level of safety. However, there was still a small percentage of low-safety areas that urgently needed to be improved.

The insecurity area was highly correlated with various historical and cultural villages and towns. It overlapped with Zhenze Ancient Town, Xitang Ancient Town, Tongli Ancient Town and Zhujiajiao Ancient Town in space. The relative insecurity area was the buffer zone of the insecurity area, and together with the insecurity areas in the northeast, southeast, northwest and southwest, formed four low-value areas of cultural landscape security. These areas had high ecological and cultural risks. General security areas covered many key construction areas, such as Chonggu Town in Qingpu, Wujiang Economic and Technological Development Zone and Tianning Town in Jiashan. Due to the influence of human activities, there was certain protection pressure on the cultural landscape in the region. The relative security areas were mainly distributed in the outer ring of each general security area, showing continuous irregular patches. The close distance between patches showed an adhesion trend, and the regional connectivity was low. High security areas accounted for the most significant proportion, their related ecological and cultural resources were in good condition of management and protection and the security level of the cultural landscape was the highest.

3.3.2. Grading Strategy Guidance for Key Conservation Areas

Considering the transregional landscape geographical feature divisions (Figure 4h), the study attempted to propose various optimization strategies for the different security areas from the perspective of overall spatial conservation planning (

Table 7. Hierarchical optimization strategy of the different cultural landscape security zones in the demonstration area.

Security Area	Key Protected Areas	Policy Type	Guiding Principles
Insecurity Area	Zhujiajiao Ancient Town; Tongli Ancient Town; Zhenze Ancient Town; Xitang Ancient Town; Weitang Town	Spatial addition (Strengthening conservation measures in regional cultural landscapes)	Follow the original features of the river network or Hudang area; set up core protected areas with Zhujiajiao Ancient Town, Tongli Ancient Town, Zhenze Ancient Town, Xitang Ancient Town and Weitang Town as the core. Strictly control the integrity of the polder field system, and prohibit any development and construction in the area that may cause further degradation of the ecological environment. At the same time, taking advantage of the excellent location of each ancient town and the gathering of resources, efforts will be made to promote the local culture’s overall and large-scale development.
Relative Insecurity Area	Lili Ancient Town; Liantang Ancient Town; Jinze Ancient Town; Shengze Ancient Town; Ganyao Town; Xiayang Street; Huimin Street; Wujiang Economic Development Zone	Spatial addition (Improving the current state of security in regional cultural landscapes)	Follow the original landscape style of the river network or Hudang area. Take ecological protection as the priority principle, and strengthen the protection of waters, forests, grasslands and the polder space in Xia Yang Street, Liantang Ancient Town, Wujiang Economic Development Zone and Huimin Street to improve the quality of green space. Relying on the cultural radiation effect of the four key historical and cultural towns of Zhujiajiao, Tongli, Zhenze and Xitang, restore the physical environment and historical information of Liantang, Jinze, Lili, Shengze and Ganyao towns by removing illegal buildings and establishing cultural heritage archives, restoring their authenticity and integrity and enhancing the quality of regional values and the texture.
General Security Area	Huaxin Town; Xujing Town; Taoyuan Town; Pingwang Town; Yaozhuang Town; Tianning Town; Xianghuaqiao Street; Yingpu Street; Taihu Lake New Town; Zhanxing Village; Zhangma Village; Yegang Village; Yingdian Village; Nanshe Village	Spatial subtraction (Relieving existing conservation pressures on regional cultural landscapes)	Follow the original landscape features of the river network, Lougang and Hudang area. Continue the compound agricultural production mode based on the original polder field system in Huaxin Town, Xujing Town, Xianghuaqiao Street, Yingpu Street and Taihu Lake Area through the participation of various parties, including the government, experts and the community, and the implementation of conservation development and construction. Relying on the natural environment and cultural space around Taoyuan Town, Pingwang Town, Yao Zhuang Town and Tianning Town, the development of unique cultural tourism industries will be accelerated to integrate the natural and cultural resources of the region and build an ecological and cultural corridor, thereby strengthening the connectivity between the core nodes of the neighboring cultural landscape security pattern and alleviating the pressure on the protection of the regional cultural landscape.
Relative Security Area	Baihe Town; Chonggu Town; Zhaoxiang Town; Fenan Village; Cenb Village; Lianhu Village; Dianhu Village; Anzhuang Village; Dianfeng Village; Lianxiang Village	Spatial subtraction (Consolidating the current state of security of the regional cultural landscape)	Follow the general appearance of the four types of landscape character zoning. Stabilize the existing polder space, and ensure ecological security on the basis of appropriate low-level guided development and construction in Baihe Town, Chonggu Town and Zhaoxiang Town to promote the ecological environment and economic and industrial development of the villages and towns. Consolidate the original natural and humanistic environment of traditional villages such as Weinan Village, Zhangyan Village and Qinglong Village, further tap their historical and cultural resources, strengthen the inheritance of local culture and promote the construction of civilized villages.
High Security Area	Qidu Town; Dayun Town; Shuangxiang Village; Shagang Village; Qiansheng Village; Caihang Village; Longquanzui Village; Xigang Village	No increase or decrease (Maintaining the current state of security of the regional cultural landscape)	Follow the general appearance of the four types of landscape character zoning. Maintain the natural resources such as river and lake systems, polders and lakes in Qidu Town, Dayun Town and other relative villages. Regularly monitor the ontology of value attribute elements and the environment, and implement preventive protection.

).

4. Discussion

4.1. Importance of Natural–Cultural Methodology

In recent years, holistic and regional conservation has become the consensus in the practice of world heritage conservation [17,18]. However, in the process of the spiritual and aesthetic development of the western landscape, nature has spent most of its time wandering outside of human beings. In particular, after the 17th century, the flourishing of western rationalism, science and metrology promoted scientific knowledge to become the orthodox rational empirical tool, and widespread doubts about the validity of natural empirical perceptions arose [45]. The stereotypical thinking of rationalism is a deep-seated cause of the long-standing separation between world natural heritage and cultural heritage assessment.

In this study, the results figured that the overall ecological security in the demonstration area was excellent, with 41.77% and 22.89% of the moderate-high ecological and the high ecological security areas, respectively. The percentage of the low ecological security areas was very small, only 0.43%, dotted in Qingpu District and Wujiang District. The moderate-low ecological security areas accounted for 15.33%. Areas with moderate ecological security levels accounted for 19.58%, which was the expansion of the moderate-low ecological security areas.

On the other hand, the value security situation in the demonstration area was generally good. Among them, the low value security areas were slightly larger than the low ecological security areas (+1.59%). Spatially, it coalesced to form two high-density cores (Tongli Ancient Town and Zhenze Ancient Town) and two sub-density cores (Lili Ancient Town and Xitang Ancient Town), which did not overlap with the low ecological security areas. The high value security areas accounted for more than half of the region, at 55.76%, which was significantly larger than the high ecological security areas (+32.87%). Additionally, they basically covered the high ecological security areas in spatial terms. The moderate-high and moderate value security areas were both smaller than the ecological security assessment results at the same level, with a reduction of 15.29% and 7.68%, respectively. In summary, when a single natural or cultural method is applied to the identification of key protected areas of complex transregional vernacular cultural landscapes, the results are not the same whether it is the location of key areas or the area measurement.

After the spatial superposition calculation, the comprehensive results showed that insecurity areas accounted for 2.06%, which was an increase of 1.63% and 0.04% compared with the low ecological and low value security areas, respectively. Their spatial settlement was the sum of the low ecological and low value security areas, involving Tongli Ancient Town, Zhenze Ancient Town, Shengze Ancient Town, Lili Ancient Town, Xitang Ancient Town, Weitang Street, Zhujiajiao Ancient Town and Liantang Ancient Town. The proportion of the relative insecurity areas was slightly larger than the moderate-low value security areas (+0.53%) but smaller than the areas with moderate-low ecological security levels (−10.96%). The proportion of general security areas was greater than the moderate value security areas (+15.16%) and the moderate ecological security areas (+7.48%), which overlap spatially with the moderate-high ecological security areas to a high degree. The proportion of high security areas (43.83%) was in the middle of the high ecological and high value security areas.

The results also showed an obvious correlation between ecological security level and land use type. The higher the proportion of water and cropland, the higher the degree of ecological security, while the urban land was the opposite. Moreover, the distribution of low cultural security space in the demonstration area highly overlapped with that in densely populated urban land. All of the above verify the correlation between security levels, natural waters and human influence activity intensity.

The significance of this study is to prove that it is necessary to establish a more comprehensive and structured methodology for the security pattern of vernacular cultural landscapes. Additionally, the methodology should be based on a long-term, continuous temporal evolutionary restoration process and multi-dimensional value conservation. It can not only help broaden the resource and ecological protection idea but also enrich and improve the holistic conservation of international natural and cultural heritage theory. We combined the characteristics of the study area and the research results for further analysis.

4.2. Security Pattern Indicators for Integrated Conservation

It is important to identify the indicators for constructing a nature–culture integrated security pattern in this specific case study. The existing traditional ecological environment assessment mainly focuses on the ecological risk assessment with altitude, slope, soil type, surface coverage and land use distance as vital influencing factors [46,47,48] or the evaluation of specific risk sources such as flood risk and geological disaster [49,50]. This study tried to measure the ecological security level of the demonstration area in a holistic and reverse method through the disturbance and vulnerability index from a landscape pattern perspective.

The evaluation system of value importance and value quality was constructed using the five heritage values of history, science, aesthetics, culture and society as criteria, and the standards of authenticity and integrity as principles. It is particularly important to note that human beings have long been involved in the cycles of natural ecosystems through their production and living practices, and they formed an interdependent relationship with nature, giving rise to a range of traditional scientific knowledge, belief systems and practical wisdom in resource management [51]. This process has contributed to the formation of distinctive vernacular cultural landscapes, which have become an essential medium for expressing the natural and cultural diversity in different areas. Therefore, in assessing the value, we have taken into account the concrete embodiment of indigenous knowledge in the index which maintains the core value of human–water symbiosis.

The demonstration area is generally low-lying with a network of water. It is the area with the most serious threat of flooding and the most prominent water conflicts in the Taihu Lake basin in China. In response to this natural environment, local residents have transformed the silt into fertile soil by excavating rivers, building embankments and reclaiming fields, thus creating a unique polder landscape system. On the one hand, the polder system has a strong function of flood detention and drainage. It turned water damage into water conservation by flexibly deploying water resources through the construction of dykes, the dredging of rivers and the installation of sluices. This objectively preserves the local ecological environment. On the other hand, the polder system, as a self-sufficient and efficient mode of complex agricultural production, effectively guarantees the food supply and economic development. It provides the residents with a material basis for sustainable survival. Furthermore, the intangible cultural heritages derived from the polder system, such as the silk weaving technique and the fishing song technique, have also influenced the socio-humanitarian environment of the demonstration area profoundly and comprehensively. Thus, the whole vernacular landscape centered on the polder system, including the local built heritage, water environment and people involved, is the embodiment of the indigenous knowledge system in this region. The assessment of these indicators also reflects the degree of adaptation to the environment, the intensive practice of resource use and the cultural transmission of experiential knowledge by the residents, characterizing the value quality of the vernacular cultural landscape.

Indigenous knowledge is embedded in culture and has regional and social uniqueness [52]. That said, when this integrated assessment framework is applied to other global regions, the association of local knowledge with cultural landscape values should also be fully considered and reflected in the value assessment indicators.

4.3. Limitations and Future Research

Firstly, the degree of “mutual construction” in the local cultural landscape needs to be further explored. This study adopted the equal weight of nature and culture to conduct a quantitative evaluation. In future research, we will focus on the different contribution rates of nature and culture in shaping the vernacular cultural landscape. Secondly, due to limited time and a large number of evaluation objects, the cultural value scoring work involved in the study was all completed by the members of the research group after the field survey, which belongs to “external evaluation”. Although interviews were conducted with local communities, managers and other relevant stakeholders to obtain the “internal perspective” of local knowledge, due to the differences in “the way of seeing”, the opinions of local communities should be included in the value scoring link in further research. This multi-agent assessment is conducive to transforming local knowledge from the role of “background” and “providing data” to local knowledge participation in management and providing future solutions.

5. Conclusions

In this study, we emphasized that high-quality ecological and green development depends on integrating nature and culture. The study proposed a conceptual framework for constructing transregional vernacular cultural landscape security patterns. According to the scientific security pattern analysis results, more targeted environmental protection response measures can be formulated. The framework consists of three steps: value refining, security evaluation and pattern construction from the perspective of time sequence and measurement. In addition, security assessment includes the evaluation of landscape disturbance, landscape vulnerability and the landscape loss index, value importance and value quality, which can be evaluated consistently and logically in this framework. The study also proposes how to formulate the optimization strategy of different security zones according to local landscape characteristics of geographical space units. The case study shows that the overall performance of the security pattern in the demonstration area was excellent. However, there was still a low-security area of approximately 6.43% that urgently needed to be improved. Our conceptual framework, indicators and evaluation methods for vernacular cultural landscape security can be widely used for the identification, improvement and spatial planning of key protection areas at transregional scales and in related research.