Harnessing Traditional Ecological Knowledge for Ecological Security Optimization in Karst Border Regions: A Case Study of Guangxi–Vietnam

Abstract

This study focuses on the ecological security of the Guangxi–Vietnam karst border region, introducing an innovative framework that integrates traditional ecological knowledge (TEK) with modern GIS-based ecological modeling to promote sustainable development. Using remote sensing, geographic information systems (GIS), and ecological sensitivity assessments, this research identifies key ecological sources, corridors, pinch points, and barriers. Unlike conventional approaches that rely solely on biophysical indicators, this study incorporates TEK-derived ecological practices into ecological network optimization, ensuring that conservation strategies align with local knowledge and cultural sustainability. Ecological sensitivity was evaluated through indicators such as soil erosion, rocky desertification, and geological disaster risks to guide the optimization of ecological networks. TEK practices, including afforestation, rotational farming, and biodiversity conservation, were systematically integrated into the construction of an innovative “three axes, two belts, and six zones” ecological security pattern. The results revealed 55 ecological corridors, 80 ecological pinch points, and 14 ecological barriers, primarily located in areas with high human activity intensity. This study advances ecological security planning by demonstrating a replicable model for TEK-based conservation in transboundary karst landscapes. By integrating traditional knowledge with modern ecological methodologies, it enhances biodiversity conservation, ecosystem connectivity, and resilience. The proposed framework provides actionable insights for sustainable urban–rural coordination and ecological restoration in karst landscapes, contributing to the long-term sustainability of ecologically vulnerable and culturally diverse regions.

1. Introduction

The policy framework worldwide is increasingly concerned about ensuring a balance between ecological protection and environmental sustainability. International treaties, such as the 2030 Agenda for Sustainable Development and the Convention on Biological Diversity, emphasize the significance of protecting and restoring at least 30% of key ecosystems, and the Paris Agreement highlights the urgency of addressing climate change [1]. Despite global policy efforts, ecological degradation remains critical. Urbanization, overexploitation of resources, and climate change have intensified the imbalance between the supply and demand of ecosystem services worldwide [2,3,4,5]. In this real-life context, the ecological security pattern (ESP) is an important strategy for balancing development and protection as an effective planning tool [6,7,8]. The application of ESP can not only mitigate environmental pressure in ecologically sensitive areas, but also serve as a scientific foundation for global sustainable development, thereby ensuring the long-term protection of ecological responses [9,10].

ESP originated from landscape ecology, aiming to maintain ecosystem stability and functionality through scientific planning of regional ecological structures [11]. The core concept of ESP is to ensure the effective flow of matter, energy, and biological information within ecosystems. This is achieved through the identification of ecological sources, the establishment of corridors, and the optimization of key ecological nodes, which collectively support biodiversity and ecosystem functionality [12]. Over time, ESP has evolved into a key tool for addressing global environmental and development challenges, particularly in response to climate change, urban expansion, and resource overexploitation [13,14]. It employs various research approaches, including the Minimum Cumulative Resistance (MCR) model, Circuit Theory, and the Pressure–State–Response model, widely applied in ecologically sensitive areas [14,15,16]. With its increasing adoption, ESP research has expanded across multiple spatial scales, ranging from national and regional studies to urban agglomerations, watersheds, and localized ecological corridor design [5,17]. At the application level, ESP has shifted from a single biodiversity conservation focus to a multi-objective framework incorporating ecosystem services [10,18]. The core of this multi-objective planning is to balance provisioning, regulating, and cultural ecosystem services, ensuring that local livelihood needs are met while sustaining ecosystem health and functionality over the long term. Given the intensifying impacts of climate change, ESP must enhance ecosystem resilience and adaptability to future environmental shifts [3].

China has played an active role in ESP research and practice, benefiting from its extensive biodiversity. It has made significant progress in promoting the development of an ecological security system. The ecological security policy established by China recently emphasizes the development of an ecological security barrier system, comprehensively improving the ecosystem service systems, enhancing the stability and resilience of the ecosystem, and building an optimum degree of ecological network to achieve the goal of “equal emphasis on quantity and quality” of the ecosystem, and coexistence between man and nature [19]. China’s ESP research combines theory with practice, not only drawing on international experience in theoretical approaches, but also combining China’s geographical environment and ecosystem responses. For example, for China’s complex mountain, wetland, grassland, and farmland landscapes, researchers have developed an ESP model adapted to China’s national conditions through multi-scale analysis [20,21,22]. Especially in areas where urbanization is rapidly advancing, the application of ESP can effectively slow down ecological degradation and improve regional ecosystem service functions [10,23]. At the same time, China is also culturally diverse, with various ethnic groups having accumulated extensive traditional ecological knowledge (TEK) through long-term interaction with their environments. This knowledge plays a crucial role in reinforcing the country’s ecological security strategies, with the core concept of harmonious coexistence between natural and anthropogenic activities. The study of ecological security patterns has gradually shifted from focusing on the ecosystem itself to emphasizing the close connection between ecology and the social and economic systems [24,25]. Behind this concept lies a re-examination of the interaction between humans and natural aspects, emphasizing the improvement of the service functions of natural ecosystems via ecological protection and restoration, thereby providing a healthier and safer ecological environment for human society.

Guangxi, located along the coast and river along the China–Vietnam border, has the most spectacular karst landforms in the world. Its ecological environment quality continues to rank among the best in the country, and it bears the major responsibility of maintaining ecological security in southern China. It has attracted much attention for its unique karst landforms and complex ecosystems [26] and is highly biodiverse with ecologically sensitive regions. The intensification of industrialization and urbanization has led to growing constraints on ecological resources, making biodiversity conservation and ecological security increasingly urgent challenges [26,27,28]. Although existing research has made some progress in biodiversity conservation and ecological restoration [29,30], overall, current research is focused on a single city or local area, lacking a holistic study of the Guangxi section of the China–Vietnam border, and often identifying ecological factors and corridors from the perspective of landscape ecology before proposing suggestions for optimizing ecosystem connectivity, which lacks integration with actual local conditions [22,31].

This limitation has led to insufficient regional coordinated management and regional adaptability, and has left existing research unable to fully respond to the complexity of ecological and socioeconomic requirements. Traditional ecological knowledge (TEK) encompasses the practices and beliefs pertaining to interdependent interactions between biodiversity and its spatial context. In the course of thousands of years, they have accumulated experience through continuous trial and error, lived in harmony with the ecological environment, and formed a variety of cultures. At the same time, they have also accumulated a large amount of undiscovered local ecological knowledge (LEK) and TEK. Although they are not directly involved in the optimization process of the modern ecological security system, they provide valuable guidance and suggestions for ecological management. Especially in areas where ecological challenges are prominent and which modern science and technology find difficult to cover, TEK provides important references for species habitat identification and early warning of environmental changes [32,33]. At the same time, different concepts in protecting and restoring ecological factors and maintaining a harmonious relationship between man and the climate are highly forward-looking and effective. Therefore, in response to the ecological challenges in China’s Guangxi–Vietnam border area, future research is required to break through the existing limitations, adopt a holistic ecological security system development method, and pay more attraction to the application of TEK. By integrating TEK with modern ecological protection technologies, the adaptability and resilience of the ecosystem can be improved, thereby promoting the long-term effectiveness of ecological protection.

To address this challenge, this study delves into how TEK can be systematically integrated into modern ecological security frameworks to enhance ecological resilience in karst border regions. It focuses on three key scientific questions: 1. What role does TEK play in optimizing ecological security patterns, and how can it be effectively incorporated into ecological network design? 2. How do ecological sources, corridors, and pinch points function within the ecological security network, and what spatial patterns emerge from their distribution? 3. How do factors such as soil erosion, rocky desertification, and geological disaster risks influence ecological sensitivity and network connectivity, and how can TEK-based strategies improve resilience?

To answer these questions, the present study selected eight counties and cities in China’s Guangxi–Vietnam border area as the research objectives, and systematically constructed the ecological security system in view of the complex karst landforms and ecological sensitivity in the region. By applying remote sensing, GIS, and ecological sources, corridors and key ecological nodes are identified based on the importance of ecosystem and environmental sensitivity, and the connectivity and stability of the ecosystem are comprehensively evaluated. At the same time, an attempt is made to integrate TEK with modern technology, and an optimization method for the ecological security system that is more in line with the regional ecological and cultural background is proposed. This novel research framework not only improves the adaptability and resilience of the ecosystem but also contributes to enhancing ecosystem resilience and sustainability, facilitating the coordinated governance of urban and rural areas under the guidance of ecological wisdom. Furthermore, this method provides a more targeted and sustainable strategy for the long-term protection of the ecosystem and offers a new theoretical basis and practical reference for the development of regional ecological security systems and ecological protection strategies.

2. Materials and Methods

2.1. Study Area

The study area is located on the Sino-Vietnamese border of Guangxi Zhuang Autonomous Region, China, including Napo County, Jingxi City, Daxin County, Longzhou County, Pingxiang City, Ningming County, Fangcheng District, and Dongxing City (Figure 1). These cities border Cao Bang, Ha Giang, Quang Ninh, and Liangshan provinces in northern Vietnam, forming an ecological and economic community of great strategic significance. The terrain in the region is dominated by typical karst landforms, with a broken surface and connected mountains and rivers, forming an overall geographical unit of the karst plateau in southwest China and northern Vietnam. The region has a subtropical monsoon climate with a humid climate, sufficient annual rainfall, and a distinct dry and wet season distribution, forming rich biodiversity and unique geological landscapes, which provide important support for regional ecosystem responses. However, the soil of karst landforms is poor and easily eroded, making the regional ecosystem vulnerable to external interference and degradation. Due to the effect of human activities, i.e., agricultural development and mineral mining, the region faces severe challenges of land degradation, ecological fragmentation, and biodiversity reduction [34]. As a border region, this area is not only an ecologically fragile karst landscape, but also a critical ecological security barrier between China and Vietnam. Its ecological integrity directly impacts cross-border environmental stability, biodiversity conservation, and national security. The unique geographical location makes it a vital ecological buffer and a key component in shaping the regional ecological security landscape [28].

2.2. Data Sources

The basic data incorporated in this experiment include land use data [35] along with environmental and human activity information presented in

Table 1. Detailed description of environmental and human activities.

Data		Spatial Resolution	Sources
Land use data	China land cover dataset (CLCD)	30 m	https://zenodo.org/records/ (accessed on 15 April 2024)
Environmental data	Net primary productivity (NPP)	500 m	https://earthengine.google.com/ (accessed on 15 April 2024)
	Digital elevation model (DEM)	30 m	https://www.nesdc.org.cn/ (accessed on 15 April 2024)
	Precipitation (Pre)	1 km	https://data.tpdc.ac.cn/ (accessed on 15 April 2024)
	Evapotranspiration (Eva)	1 km	https://www.geodata.cn/ (accessed on 15 April 2024)
	Soil information	1 km	https://www.fao.org/ (accessed on 15 April 2024)
	Normalized difference vegetation index (NDVI)	30 m	https://www.nesdc.org.cn/ (accessed on 15 April 2024)
Human activity data	Human footprint index (HFP)	100 m	https://www.earthdata.nasa.gov/ (accessed on 15 April 2024)
	Human density (HD)	90 m	https://landscan.ornl.gov/ (accessed on 15 April 2024)

. All data primarily use 2022 datasets, and for variables where 2022 data was unavailable, the nearest available year’s dataset was used to minimize errors. All data were obtained from authoritative and publicly available sources, ensuring their authenticity, reliability, and scientific credibility. All data are in the unified coordinate system of WGS1984 with a spatial resolution of 30 m × 30 m (Figure 2).

2.3. Methods

Referring to relevant demonstrations, this study selected ecosystem service responses like balance of biodiversity, water utilization, soil conservation, and carbon sequestration to assess ecological source areas, combined with the sensitivity of soil erosion, desertification, and geological disaster. The environmental vulnerability of the region was evaluated, and the minimum cumulative resistance model and circuit theory were applied to identify ecological corridors, ecological study points and challenges, and to identify the ecological security pattern of the study area. On this basis, TEK was integrated into the optimization process of the ecological security system and a more resilient and sustainable ecological protection plan was proposed in combination with local TEK, such as desertification response measures, water bird habitat protection, agricultural biodiversity protection, and plant diversity protection and utilization. The research paradigm is elucidated in Figure 3.

2.3.1. Source Identification

Ecological sources are the sources where species are maintained and developed, and play a major role in maintaining ecosystem stability and upgrading the sustainable development of ecosystems [23]. Quantitative analysis of the importance of ecosystem services is a scientific application for assessing ecological sources [36]. This paper quantitatively analyzes the biodiversity, water, soil conservation, and carbon fixation functions, normalizes them, performs equal weight superposition, extracts high-value patches, and aggregates to obtain ecological resources in the study region.

(1)

Biodiversity service function assessment

Biodiversity service function is an indicator for assessing the ability of a region to maintain biodiversity. Its calculation equation as follows [22].

$$Sbio={NPP}_{mean}\times F_{pre}\times F_{tem}\times \left(1-F_{alt}\right)$$

(1)

where ${NPP}_{mean}$ is the average of net primary productivity, $F_{pre}$ refers to the average rainfall, $F_{tem}$ is the temperature, and $F_{alt}$ is the altitude. All data are normalized.

(2)

Water retention function

In ecosystems such as forests and grasslands, the interaction with water is facilitated through the intrinsic mechanisms of interception, infiltration, and storage of precipitation, as well as the regulation of water flow and circulation via evapotranspiration processes [37]. The water retention in this article is based on the water yield utilization of the InVEST 3.14.1 model, and calculated and corrected using the terrain index, soil saturated hydraulic conductivity, and flow velocity coefficient [38].

$$WR=min (1,{\displaystyle \frac{249}{Velocity}})\times min (1,{\displaystyle \frac{0.9\times TI}{3}})\times min (1,{\displaystyle \frac{K_{sat}}{300}})\times Y$$

(2)

$$TI=\mathit{ln}( {\displaystyle \frac{\alpha }{\mathit{tan} \beta }})$$

(3)

$$K_{sat}=114.8\times {10}^{-0.6+1.26\times 0.01\times C2-6.4\times 0.001\times C1}$$

(4)

where $WR$ is water conservation capacity (mm); $Velocity$ is the velocity coefficient, observed in a dimensionless manner by consulting the literature and integrating the actual situation of the experimental region; TI is the terrain index, dimensionless; $\alpha$ is the unit area runoff, obtained by hydrological analysis of DEM data in ArcGIS 10.2; $\beta$ is calculated from slope data in ArcGIS; $K_{sat}$ is the saturated hydraulic conductivity of soil (mm/d); $C1$ and $C2$ are the % content of clay and sand soil; and $Y$ is water yield (mm), observed by the yield water module of the InVEST 3.14.1 model.

(3)

Soil and water conservation service function

The soil and water conservation service system is important for assessing the significance of ecosystem services in karst landform regions. It is mainly based on the soil, topography, and vegetation [22]. Its calculation equation as stated:

$$SR=R\times K\times L\times S\times (1-C)$$

(5)

where $SR$ is the soil and water conservation service function, $R$ is the rainfall erosivity factor, $K$ is the soil erodibility factor, $L$ is the slope length factor, $S$ is the slope factor, and $C$ is vegetation cover factors.

(4)

Carbon sequestration service function

Carbon sequestration response is a major component of climate regulation. Its calculation equation is as follows [39]:

$$CF=C_{above}+C_{below}+C_{soil}+C_{dead}$$

(6)

$CF$ represents carbon fixation capacity, $C_{above}$ aboveground carbon storage, $C_{below}$ underground carbon storage, $C_{soil}$ soil organic matter content, and $C_{dead}$ organic carbon storage of dead organisms. The units are all t(hm)⁻². The corresponding data of each land use type are presented in

Table 2. Characteristics assignment for the evaluation of carbon fixation capacity of various types of land use.

Type of Land Use	Cabove	Cbelow	Csoil	Cdead
Cropland	11.62	2.32	14.92	1
Forest	50.16	12.54	16.98	3.5
Shrubbery	32.92	8.23	9.7	2.47
Grassland	2.59	11.64	13.77	1
Water	0.18	0	0	0
Barren	1.81	0	9.77	0
Impervious	1.03	0.8	10.74	0

.

2.3.2. Resistance Surface Construction

The ecological resistance surface refers to the spatial distribution of resistance to ecological responses, i.e., plant variety migration and flow of energy in different regions of the landscape. It usually reflects the effects of landscape heterogeneity on ecological flow by integrating factors such as land use type and ecological sensitivity [39,40]. This study uses the inverse data value of habitat quality and population distribution density, and weighted superposition by the Delphi method [22].

The calculation equation is as follows:

$${ER}_i={\displaystyle \frac{1}{{HQ}_i}}\times W_{HQ}+{HD}_i\times W_{HD}$$

(7)

where ${ER}_i$ is the basic resistance coefficient of grid $i$, ${HQ}_i$ is the habitat quality of grid $i$, $W_{HQ}$ is the habitat quality weight and its value is 0.5, ${HD}_i$ is the population density of grid $i$, and $W_{HD}$ is population density weight, and its value is 0.5.

In the process of habitat quality evaluation, the parameter values for different land use types and threat sources were determined based on studies conducted in similar regions and landforms [22,28] (

Table 3. The optimum distance over each category affects habitat quality and weight.

Threat	Optimum Distance	Weight	Decay
Cropland	2 km	0.5	linear
Impervious	10 km	1	exponential
Railway	5 km	0.6	exponential
Road	2 km	0.6	exponential

). Similarly, the sensitivity values of various land use types were also derived from relevant research on comparable ecological settings (

Table 4. Sensitivity of habitat types to threat factors.

Habitat Types	Habitat Value	Cropland	Impervious	Railway	Road
Cropland	0.6	0.4	0.6	0.5	0.6
Forest	1	0.7	0.9	0.9	0.9
Shrubbery land	1	0.6	0.5	0.5	0.5
Grass	0.7	0.7	0.75	0.4	0.75
Water	0.9	0.7	0.9	0.85	0.9
Bare ground	0	0	0.4	0.9	0.9
Impervious	0.2	0.2	0	0.2	0.1

). The China–Vietnam border region is mostly karst landforms, and its soil erosion, desertification, and susceptibility to geological disasters also have an important impact on biological migration. At the same time, its soil and water conservation capacity and ability to maintain biodiversity will also affect regional ecological processes. Therefore, the ecological sensitivity and significance of ecosystem services are selected to modify the resistance coefficient of each grid and construct the minimum cumulative resistance surface.

Ecosystem vulnerability and responsiveness are characterized by their inherent susceptibility to variations in the natural environment and perturbations caused by human activities [41]. Highly sensitive areas are more likely to experience ecological imbalance and environmental hinderance when disturbed by external factors [7]. Ecological sensitivity is usually evaluated through multiple indicators, such as freeze–thaw erosion, soil erosion, land desertification, and landslide disasters [42]. By comprehensively evaluating these indicators, ecologically sensitive areas can be effectively identified and managed, and the scientific quality and accuracy of ecological protection and management can be improved [43]. Based on the karst landforms in the experimental region, this study selected three evaluation indicators, soil erosion, rocky desertification, and geological disaster sensitivity. After normalization, the comprehensive assessment of ecological sensitivity was generated by equal weight superposition, which was divided into high sensitivity, relatively high sensitivity, moderate sensitivity, relatively low sensitivity, and low sensitivity. The evaluation indicator classification is shown in

Table 5. Evaluation index and quantitative classification of ecosystem environmental sensitivity.

Evaluation Index	Minimum Sensitivity	Lower Sensitivity	Medium Sensitivity	Higher Sensitivity	Maximum Sensitivity
	1	3	5	7	9
Rainfall erosivity	<6963	<9878	<12792	<15149	>15149
Soil erodibility	0–0.2	0.2–0.54	0.54–0.69	0.69–0.82	0.82–1
Topographic relief	<67	67–124	124–178	178–245	245–686
FVC	0	0–0.68	0.68–0.85	0.85–0.93	0.93–1
D (%)	0–3	3–6	6–9	9–12	12–15
Slope	0–8	8–17	17–26	26–37	37–78
NDVI	0–0.38	0.38–0.62	0.62–0.78	0.78–0.86	0.86–1
HPF	1.72–10.63	10.63–16.49	16.49–23.31	23.31–33.34	33.34–50

.

(1)

Soil erosion sensitivity

Soil erosion sensitivity is calculated using rainfall erosivity, soil erodibility, terrain relief, and vegetation cover factors. The calculation equation is as follows:

$${SE}_{SS}=\sqrt[4]{R\times K\times LS\times C}$$

(8)

where ${SE}_{SS}$ is the soil erosion sensitivity, and $R, K, LS,$ and $C$ are the sensitivity grades of rainfall erosivity factor, soil erodibility factor, terrain relief factor, and vegetation factor, respectively.

(2)

Desertification sensitivity

The desertification sensitivity is calculated by using the carbonate rock outcrop area ratio, slope, and NDVI. The calculation formula is as follows:

$${RDE}_{SS}=\sqrt[3]{D\times P\times C}$$

(9)

where ${RDE}_{SS}$ is the calculated desertification sensitivity, and $D, P,$ and $C$ are the sensitivity classification values corresponding to the proportion of carbonate rock outcropping area, slope, and NDVI, respectively.

(3)

Geological hazard sensitivity

The geological hazard sensitivity calculated using slope, terrain factors, and vegetation coverage. The calculation equation is as follows:

$${GH}_{SS}=P\times W_P+LS\times W_{LS}+\complement \times W_C+H\times W_H$$

(10)

where $P, LS, C$ and H are the sensitivity classification values of slope, terrain factors, vegetation coverage, and human activity intensity, respectively. $W_P$, $W_{LS}$, $W_C$, and $W_H$ are the weights corresponding to the above four indicators, which are determined to be 0.3, 0.3, 0.15, and 0.25, respectively, through tomography analysis.

Finally, the resistance coefficient of each grid is corrected according to the calculated ecological sensitivity assessment results to obtain the corrected resistance surface. The correction equation is as follows:

$${ERf}_i=({\displaystyle \frac{{ES}_i}{{ES}_a}}+{\displaystyle \frac{1}{ESF}})\times {ER}_i$$

(11)

where ${ERf}_i$ is the modified resistance coefficient of grid $i$, ${ES}_i$ is the ecological sensitivity of grid $i$, ${ES}_a$ is the average ecological sensitivity of grid $i$ corresponding to land use type $a$, $ESF$ is the importance of ecosystem services of grid $i$, and ${ER}_i$ is the basic resistance coefficient of grid $i$.

2.4. Development of Ecological Security System

2.4.1. Extraction of Ecological Corridors

The development of ecological corridors is essential for enhancing biodiversity conservation and maintaining ecosystem services by connecting ecological sources into a well-structured ecological network [18]. This study uses the Linkage Pathways-Build Network and Map Linkages tool (Version 2.0) in the Linkage Mapper toolbox (Version 2.0) to calculate the cumulative resistance value of the resistance surface needed for plant varieties to migrate from one ecological source to another based on the minimum cost path method [23]. The cost-weighted distance is set to 400 km, and the resulting minimum cost path represents the ecological corridor.

2.4.2. Evaluation of Ecological Pinch Points and Barrier Points

Ecological pinch points are key channels for the flow of species, energy, and materials in ecological networks. Ecological pinch points are not only the link between different ecological sources, but also an important link in maintaining the connectivity of the complete ecological network [44]. Therefore, any external interference will have a significant negative effect on the overall function of the ecosystem. Through the Circuitscape and Pinchpoint Mapper tools (Version 2.0), the ecological flow path is simulated and the areas with optimum current density are assessed. These areas are designated as ecological pinch points, indicating important channels for species migration [31].

Ecological barrier points refer to key areas in ecological networks or ecological corridors that hinder the flow of species, energy, and materials due to natural or human factors [45]. Use the BarrierMapper tool (Version 2.0) to set a specific search radius and search for ecological barrier points through the moving window method. Set a radius range of 100–600 m and a radius step of 100 m for iterative calculations. By calculating the difference in the low-cost distance before and after removing the obstacle point, the impact of the obstacle point is quantitatively evaluated to identify and manage these key areas.

2.5. Ethnoecological Survey Method

The ethnoecological survey approach is a method that combines anthropology and ecology. It aims to explore how local communities interact with the natural environment and manage natural resources through daily practices through field research [46,47]. This study first adopted a literature research method to initially understand the basic conditions of the survey area, such as natural geographical conditions, farming methods, plant resource protection, animal protection, and traditional folk culture. Then, ethnoecological research approaches, i.e., participatory observation, semi-structured interviews, and key person interviews, were used to understand in detail the knowledge and experience accumulated by local residents in long-term ecological management.

3. Results

3.1. Significance of Ecosystem Functions

Overlay the four ecosystem service functions and classify them into five levels based on natural breaks. Levels 1–5 represent the lowest to the optimum level of significance. All ecosystem service responses showed spatial heterogeneity (Figure 4). The results showed that the ecologically major area of China’s Guangxi–Vietnam border zones is 870.25 km², accounting for 4.18% of the total area of the experimental area. The optimum value areas of ecosystem service importance are concentrated mainly in the central and northern parts of Dongxing City. The area of the ecologically more important areas is 2251.18 km², accounting for 10.87% of the total area. They are scattered in a circle along the extremely important areas of ecological service values and concentrated in Fangcheng District. The area of the ecologically important area is 6666.47 km², accounting for 32.19%, mainly distributed in the central and southern parts of Ningming County, the southern part of Napo County, the northeastern and northwest of Daxin County, and the northern part of Longzhou County. The areas of the ecologically less important and unimportant areas are 6719.18 and 4205.29 km², respectively, accounting for 32.45 and 20.31% of the total area, respectively. They are distributed in all counties in the study area, and are more obvious in the central part of Longzhou County and the central part of Ningming County to the north. In particular, they are focused in the southern part of Dongxing City, forming a fault contrast with the high-value service importance areas in the north of Dongxing City.

3.2. Ecological Sensitivity Assessment

By superimposing and analyzing various ecological sensitivity evaluation indicators, the natural breakpoint procedure was applied to divide the comprehensive assessment indicators of ecological sensitivity in the study area into five categories: low sensitivity, relatively low sensitivity, medium sensitivity, relatively high sensitivity, and high sensitivity (Figure 5). Overall, the ecological sensitivity of the study area is mainly moderately sensitive, with an area of 6834.43 km², accounting for 32.99%, followed by a high-sensitivity area, with an area of 5223.45 km², accounting for 25.21%. It is mainly distributed in the northern part of the study area, and the central part is obviously separated by the low-sensitivity area. The main land type is forest type, the degree of human activity interference is relatively low, and the ecological comprehensive sensitivity is relatively low. The area of the low-sensitivity zones is 2384.08 km², accounting for 11.51%, mainly distributed in the central part of Ningming County and Longzhou County and the eastern part of Fangcheng District. The land use type is mainly agricultural-based land. Although the degree of human interference is strong, its soil retention capacity, desertification degree, and geological disaster risk are relatively low. The area of the highly sensitive zone is 1539.27 km², accounting for 7.43%. It is mainly distributed in scattered and strip forms. The scattered distribution is mainly in Napo County and the southwest of Daxin County, and the strip distribution is mainly on the northern edge of Fangcheng District. The land use types are mainly forest and farmland. Although the degree of human interference is low, the terrain inside the region undulates, the risk of geological disasters is extremely high, and there is extremely strong sensitivity.

3.3. Source Identification

After superimposing the weights of biodiversity maintenance, water conservation, soil and water conservation, and carbon fixation service function layers, the comprehensive assessment results of ecosystem services are monitored. The experimental region is categorized as important, relatively important, generally important, less important, and unimportant, corresponding to levels one to five. The relatively important and important areas of ecosystem services are selected, and the scattered and relatively low ecological service value patches are eliminated. After screening, they are selected as ecological sources (Figure 5). According to statistics, the area of ecological sources in China’s Guangxi–Vietnam border zones are 1536.3 km², accounting for 7.4% of the experimental region.

From a spatial perspective, these ecological sources are mainly distributed in the north of Dongxing City, the middle and west of Fangcheng District, and the southeast of Ningming County. They are scattered in Daxin County, Jingxi City, and Napo County. They are mainly distributed in the southern region with low altitudes and gentle terrain fluctuations. The habitat quality is high and the ecosystem service function is good. There is no distribution in Longzhou County and Pingxiang City. Although these two areas are at low altitudes, the terrain fluctuations are large.

From the perspective of landscape distribution, forest and cropland are the main land types in ecological sources, accounting for 95.80 and 3.89% of the ecological source area in the study area, respectively, followed by impermeable surfaces, mainly including buildings, roads, parking lots and other hardened surfaces, shrubs, and water areas, accounting for 0.13, 0.12, and 0.05%, respectively. However, some impermeable surfaces are adjacent to nature reserves and geological parks, and they play a specific buffering role in ecological reserves and can provide service functions in soil and water loss prevention and control, and urban drainage and flood control, thus becoming part of the source, reflecting the contradiction and conflict between ecological protection and restoration on the one hand and urban construction and development on the other.

From the perspective of regional characteristics, Fangcheng District has a large ecological source area, accounting for 73.52% of the total ecological source area, followed by Dongxing City and Ningming County, accounting for 14.29 and 9.29%, respectively, followed by Daxin County, Jingxi City, and Napo County, accounting for about 1% each, while Longzhou County and Pingxiang City have no ecological source area, indicating that their ecological needs are urgent and that there is a contradiction between ecological protection and restoration, and economic development. Forest land occupies an absolute advantage in the composition of ecological sources. Forests in Fangcheng District account for 96.78% of the total ecological source area in the district, and in Ningming County, they account for 97.49%. It is worth noting that, in Dongxing City, which ranks third in the proportion of ecological sources, the proportion of cropland is much higher than in other regions (9.91%).

3.4. Construction and Modification of Resistance Surface

The habitat quality of the experimental region is obtained through the Habitat Quality module in the InVEST model, and the inverse of the habitat quality and the population distribution density are further weighted and superimposed according to the Delphi method to obtain the basic resistance surface of the region. Based on the findings of ecological sensitivity identification, the resistance coefficient of each grid was corrected to obtain the corrected resistance surface (Figure 6). The spatial distribution of resistance values in the study area varies greatly. The optimum resistance values are mainly concentrated in the eastern part of Jingxi City, the eastern part of Daxin County, the northwestern part of Ningming County, the western and northern parts of Pingxiang City, the southwestern part of Dongxing City, and the eastern part of Fangcheng District. The land use types in the above areas are mainly construction land, with optimum levels of economic development and dense population, which has resistance to the migration of species in the surrounding areas. The medium ecological resistance value area is widely distributed north of the boundary, with the central part of Ningming County as the boundary. The land use type in this area is a staggered distribution of farmland and forest, and the degree of human interference is relatively high, which has some negative effects on the diffusion behavior of species. The low-value area is distributed in Fangcheng District and Dongxing City south of the boundary. The land use type in the low-value area is mainly forest, with limited intensity of human activities, and low average altitude, but higher terrain undulation. The habitat quality is good and conducive to the diffusion of species.

3.5. Evaluation of Ecological Corridors, Study, and Obstacle Points

3.5.1. Corridor Identification

Based on the minimum cost path approach, the Linkage Mapper was applied to observe the ecological corridors in the experimental region. A total of 55 ecological corridors were screened (Figure 7), which were basically distributed in a network with a total length of 2273.51 km. Due to the dispersion of ecological sources, seven ecological corridors were more than 100 km long, mainly connecting the ecological sources between Ningming County and Jingxi County and Daxin County. Among them, the longest ecological corridor was 267.97 km, integrating the ecological sources in the southeast of Napo County and the west of Ningming County. There were 22 ecological corridors with a length of less than 10 km, mainly connecting the ecological sources in Fangcheng District and Ningming County. The ecological sources in this area are densely distributed, with a large area but patchy distribution. Ecological corridors can maintain the connectivity and stability of ecosystems over a large range, especially in the complex and diverse terrain environment in the study area. The existence of long-distance corridors not only assists connection of ecological sources, but also upgrades the migration of cultivars between different ecological intervals and reduces the isolation effect. The dense distribution of short-distance corridors enhances the resilience of local ecological networks within the region, especially in areas with high ecological value but patchy distribution. The existence of these corridors ensures the mobility of species and genes, and maintains the functionality of the ecosystem.

3.5.2. Ecological Pinch Points

The Pinchpoint Mapper tool (Version 2.0) in the Linkage Mapper toolbox was used in combination with the Circuitscape software (4.0.5) to identify important plant variety migration channels in the experimental region. Since these channels are usually narrow and short in space, their surface areas were extracted into points, and a total of 80 ecological pinch points were assessed (Figure 7). From the perspective of spatial distribution, these ecological pinch points are mainly long-distance ecological corridors between Ningming County, Daxin County, and Longzhou County. Although the long-distance corridors in these areas play a major role in connecting various ecological sources, species will encounter various forms of obstacles during migration due to the long length of the ecological corridors. It makes these pinch points particularly important in the ecological network. In contrast, no ecological pinch points were identified in the short and densely distributed ecological corridors in Fangcheng District, probably because these corridors have good connectivity in the local area and less interference. In long-distance ecological corridors, ecological pinch points play a major role in maintaining species dispersal and gene flow. However, these areas are more vulnerable and affected by natural factors, i.e., topographic changes and climate conditions, and anthropogenic factors, like use of land and infrastructure construction. Therefore, maintaining the mobility of these ecological pinch points is not only to maintain the ecological balance of the local area, but also a key measure to ensure the stability of the entire ecological network.

3.5.3. Ecological Barrier Points

By using the Barrierspoint tool (Version 2.0) in Linkage Mapper, a total of 14 ecological barrier points were identified in this experiment (Figure 7). These barrier points are widely distributed. Except for Fangcheng District and Dongxing City, they are distributed in other counties in the experimental region. Most of these ecological barrier points are concentrated in key locations of ecological corridors, which have a negative impact on the continuity of ecosystem functions. Especially in the long-distance corridors of Ningming County, Daxin County, and Longzhou County, the existence of barrier points poses a potential threat to species migration and ecosystem connectivity. Among the 14 barrier points, 6 coincide with ecological pinch points, indicating that these points are the most vulnerable links in the key channels of species migration. At the same time, these overlapping barrier points are often crossed by roads. The existence of roads exacerbates the isolation effect of these areas and further restricts the free flow of species. The existence of ecological barrier points will have direct adverse effects on the health and connectivity of regional ecosystems.

The distribution of human activities, such as roads and urban construction, near these barrier points will also greatly increase the risk of ecosystem fragmentation. This fragmentation not only limits the natural migration and gene exchange of species, but may also lead to the local extinction of some sensitive species. In addition, the existence of barrier points may also destroy the overall connectivity of the ecological corridor, making it impossible for the corridor to play its due ecological function. For overlapping ecological nodes and barrier points, more stringent protection measures should be taken to limit or prohibit further development activities. Through the effective management of these barrier points, the connectivity of the ecological network in the region can be improved, and the stability and resilience of the ecosystem can be upregulated.

3.6. Survey on Traditional Ecological Knowledge

This study conducted an ethnoecological survey in the Guangxi–Vietnam border area from June 2023 to June 2024. Through literature review and field participatory observation, the local residents’ understanding and practices of the natural environment were elucidated (Figure 8). Based on these contents, 21 main questions were designed to conduct interviews (

Table A1. Questions emerging in the questionnaire.

Theme	Question List
Desertification control	What plants are usually grown and why?
	What planting techniques or patterns have been explored?
	In addition to their ecological role, does planting these plants have other uses in personal life?
	Do institutions and beliefs play a role in desertification control?
	What do you think of the effectiveness of desertification control?
Agriculture biodiversity	How can we make efficient use of limited land resources?
	What farm varieties are there?
	What are their advantages and disadvantages?
	What is green ecological agriculture?
	What are some good experiences and methods?
	Is traditional farming culture conducive to the protection of the ecological environment?
	What are the specific benefits?
	Is it still being continued? Is it necessary to continue?
Mangroves biodiversity	What are the specific measures for the protection of water birds?
	Which plants are suitable for water birds to inhabit?
	What is the relationship between mangrove plants and production and life?
	Why should we protect mangroves?
Plant diversity	What are the specific measures for protecting ancient trees?
	Why are these trees protected?
	What are the ways in which we can utilize wild plant resources?
	What is the relationship between plants, folk customs, and festivals?
TEK recognition	Where did the traditional usage come from?
	Are these practices being taught to children and other younger generations?
	Is this knowledge, ways, or methods still important today?
	How can we protect this traditional knowledge?

).

A total of 326 participants were involved, including farmers (108), government officials (50), businesspeople (68), individuals (66), and students (34). Their ages ranged from 17 to 94 years old, with the majority being between 47 and 75 years old (44%). There were fewer males (157) than females (169) (Figure 9). A total of 19 TEK aspects and 75 specific items in five categories related to desertification response, agricultural production, plant resource utilization, and mangrove biodiversity protection were achieved (

Table A2. Survey and catalog of traditional ecological knowledge.

Category	TEK	Introduction to TEK	Representative Biological Sources or Items
			Local Name	Botanical Name	Specific Use/Functions
Rocky desertification response	Multi-level planting	Involving a variety of life forms, it has formed a Dashishan forest ecosystem dominated by deciduous broad-leaved tree species and with obvious structural levels. These plants are all needed for daily life.	Rendou Tree	Zenia insignis	Tree layer: building materials
			Xiangchun Tree	Toona sinensis
			Caidou Tree	Radermachera sinica
			Kujian Tree	Melia azedarach	Arbor layer: using leaves to treat common diseases
			Xishu	Camptotheca acuminata	Arbor layer: fruits are edible
			Gou Tree	Broussonetia papyrifera	Arbor layer: leaves used as fodder
			Huanglu	Cotinus coggygria var. cinereus	Shrub layer: treat jaundice
			Zhuyehuajiao	Zanthoxylum armatum	Shrub layer: fruit can be made into seasoning
			Jiahuangpi	Clausena excavata	Shrub layer: fruits and leaves are edible and can be used as seasoning
			Diaosizhu	Dendrocalamus minor	Bamboo: bamboo weaving
			Datoudianzhu	Bambusa beecheyana var. pubescens	Bamboo: bamboo weaving
			Citou	Cephalaria alpina	Bamboo: edible
			Fendanzhu	Bambusa chungii	Bamboo: bamboo weaving; bamboo leaves
			Jinyinhua	Lonicera japonica	Fujimoto: tea substitute
			Mubiezi	Momordica cochinchinensis	Fujimoto: food coloring
			Wujiemang	Miscanthu floridulus	Herbaceous layer: the stems and flowers of Miscanthus quinquefolius are used to make brooms
			Hongsixian	Lycianthes biflora	Herb layer: used as medicine to clear away heat and detoxify
			Jianma	Agave sisalana	Herbaceous layer: leaves are used to make ropes
	Tree God Worship	Locals will deliberately protect a Feng Shui forest, as they believe that if it is cut down, it will inevitably bring disaster, maintaining Feng-Shui forests and protecting specific tree species	Cuibai	Calocedrus macrolepis	The locals regard it as an ancestral tree and prohibit cutting it down.
			Chongyangmu	Bischofia polycarpa	When the branches are cut, red juice oozes out, giving it supreme divinity. It is believed to be a sacred object that protects life and the village, and no one is allowed to get too close or destroy it.
	Planting native tree species	According to the characteristics of the local rocky mountain ecosystem, we selected native varieties with strong adaptability, easy growth, and high survival rate.	Rendou Tree	Zenia insignis	Commonly known as the “beheaded tree”, it has strong vitality and its roots can penetrate deep into the cracks of the rocks.
			Jinyinhua	Lonicera japonica	One Jinyihua plant can cover several or even dozens of square meters of large rocks, which can effectively reduce soil erosion and increase the ecological environment of the rocky mountain.
	Optimizing planting techniques	By exploring the properties and characteristics of plants, we explore water conservation planting techniques and reduce soil erosion.	Kujian Tree	Melia azedarach	Plant Kujian trees on rainy days; dig holes for planting, pay special attention to compacting the soil around the seedlings, and look for weeds around to cover them, avoid direct sunlight, and increase the survival rate
			Rendou Tree	Zenia insignis	The planting of Rendou trees should be carried out after the spring rain. When planting, the trees should be buried deep and compacted. It is best to cover them with grass. The planting density should not be too dense. Appropriate interplanting of low-growing crops can be used to promote the growth of Rendou trees.
			Diaosi bamboo	Dendrocalamus minor	Dig a hole for planting, find a stone piece about 20 cm long and 10 cm wide to cover it to prevent direct sunlight from shining on the tree. At the same time, some steam can be condensed at night to provide the bamboo with water for its initial survival.
	Village rules and regulations	(1) The public should actively participate in afforestation and set a planting quantity; (2) The public should strengthen the management of the forests and not cut down trees indiscriminately. If anyone is found cutting trees illegally, he will be fined three trees for every one he cuts down; (3) Restrict people from other villages from cutting grass and cutting firewood: if they are caught for the first time, they will be educated; if they are caught for the second time, they will not be allowed to bring back firewood and will be fined; (4) Daughters who marry into other villages are not allowed to return to the village to claim the forests.	Feiniu Tree	Cephalomappa sinensis	Institutional guarantee for desertification control
	Forest resource management strategy	(1) Regarding the planning of the mountains and forests, no one is allowed to enter the mountains and forests near the villages without permission, and mowing, collecting firewood, and grazing are strictly prohibited. (2) The mountains and forests near the cultivated areas are only allowed to be entered for mowing and cutting vines, and young trees are not allowed to be cut. (3) The remote mountains and forests bordering other villages are closed in rotation and opened regularly to solve the difficulties of the masses in mowing and collecting firewood. (4) While implementing the mountain closure, the masses are mobilized to plant trees and bamboo every winter and spring, digging holes in the cracks of the rocks to plant trees and bamboo	Xianmu	Excentrodendron tonkinense
	Mulberry and silkworm farming	Mulberry trees are suitable for growing in rocky desertification areas. Mulberry leaves are used to feed silkworms. Then, during the growth of mulberry trees, they are cut down twice a year in spring and autumn. The cut mulberry stalks can meet the current needs of people for firewood and cooking.	Sang tree	Morus alba	Solve the economic source of the rocky mountain area, reduce dependence on the mountains and forests, and alleviate the pressure on the rocky mountain ecosystem.
Mangrove biodiversity conservation	Waterbird habitat protection	Based on their long-term interactions with water birds, the public consciously creates habitats based on the needs and habits of different water birds.	Mumahuang	Casuarina equisetifolia	Shore protection plants to prevent habitat degradation
			Luoyushan	Taxodium distichum
			Kujian	Melia azedarach
			Baigurang	Avicennia marina	Bank protection plants
			Tonghua Tree	Aegiceras corniculatum
			Qiuqie Tree	Kandelia obovata
			Mulan	Bruguiera gymnorhiza
	Farming and waterfowl foraging	The aquaculture area on the tidal flats and the foraging areas for water birds are highly overlapped. European breams often follow fishing boats in groups. After the fishermen catch the fish, they go to the deck to forage for food. Fishermen will also deliberately leave the seafood of poor quality for the water birds. In addition to the water bird habitats within the wetland red line, artificial wetlands such as fish ponds, salt pans, and shrimp ponds in the village also provide important supplements for water bird habitats.	Honzuiou	Larus ridibundus	Agriculturally beneficial birds, controlling pest populations
			Heizuiou	Larus saundersi	Their call patterns predict changes in weather
			Qingjiaoyu	Tringa nebularia	Control insect populations and maintain ecological balance
	Waterfowl breeding	Understand the breeding habits of waterfowl and consciously protect the habitats of waterfowl	Baixiongkue Bird	Amaurornis phoenicurus	Prefers bushes near water
			Heishuiij	Gallinula chloropus	Prefers shallow waters, reed beds, etc.
			Heichihangjiaoyu	Himantopus himantopus	Prefers to be on a sunny beach or grassy area with a few plants
			Bailianheng	Sitta leucopsis	Likes to be on the beach
			Caiyu	Rostratula benghalensis	Prefers bushes near water
	Tourism and water bird conservation	Based on their long-term interactions with water birds, the public consciously creates habitats based on the needs and habits of different water birds.	Bailu	Egretta garzetta	Transforming ecological value into economic value
	Protection and utilization of mangroves	Mangroves are known as “undersea forests” and have a wide range of uses. The trees can be used as building materials, the fruits can be eaten or used to make wine, and the tannin extracted from the bark can be used as a dye.	Baigurang	Avicennia marina	The fruit boiled in water can be eaten directly as a dish
			Tonghua Tree	Aegiceras corniculatum	A nectar plant, whose quality is second only to litchi honey and which has a high yield
			Haiqi	Excoecaria agallocha
			Laoshule	Acanthus ilicifolius	Anti-cancer
			Shuihuangpi	Pongamia pinnata	The pongamia bark of the Shuihuangpi has anti-inflammatory, antibacterial, and antiviral medicinal values
			Houteng	Ipomoea pes-caprae	The intricately developed root system of mangroves can effectively retain the large amount of sediment that is transported from rivers to the ocean, thereby reducing the sand content in the coastal waters and effectively resisting the attacks of wind and waves.
			Mulan	Bruguiera gymnorhiza
			Honghailan	Rhizophora stylosa
Agricultural biodiversity conservation	Genetic resource diversity	The Sino-Vietnamese border region has a long history of agriculture and relatively rich local varieties. From the perspective of species and genes, not only are there many species of origin, but many high-quality gene types are unique to this country. The formation of these variety resource characteristics is closely related to the production and lifestyle of the local people and has rich traditional cultural knowledge.	Jingxi-Daxiang nuo	Oryza sativa	Jingxi-Daxiang nuo has few pests, high quality, and rich nutrition. According to the survey, there are at least six varieties of Jingxi Daxiang glutinous rice, and the genetic resources are very rich.
			Jingxi-Damaya	Tadorna ferruginea	Jingxi-Damaya is the largest local fine duck breed in Guangxi. This breed has the advantages of large size, tolerance to roughage, strong foraging ability, and fast early growth rate. The duck has less subcutaneous fat, high meat yield at slaughter, tender meat, and delicious taste.
			Jingxi-Daguoshanzha	Crataegus scabrifolia	The root system of the big-fruited hawthorn is well developed, which can effectively fix the soil and reduce soil erosion. At the same time, the fruit of the big-fruited hawthorn is rich in nutrients and medicinal value, and can be used as a source of food and medicine for local residents. At present, the cultivation of big-fruited hawthorn adopts traditional agricultural techniques and methods, such as crop rotation and intercropping, to effectively maintain soil fertility and water balance.
			Pingxiang-Baiyumi	Zea mays	Drought resistant, good taste
	Ecosystem diversity	The agricultural arable land area in the ChinaVietnam border area is barren. The ancestors here, in an environment with many mountains and little land, upgraded the production capacity and benefits from low efficiency to high efficiency and transformed from extensive to intensive, initially forming a green agricultural industry.	Sweet potato and rice rotation	Ipomoea batatas	Sweet potatoes are planted in October of the first year, and rice is planted after harvesting in May of the second year. In this way, one season of sweet potatoes and one season of rice can be harvested in a year, realizing the rotation of water and land. After harvesting sweet potatoes, the sweet potato vines are returned to the fields to conserve the land, which is both ecological and labor-saving, improves soil fertility, effectively eliminates farmland weeds and soil-borne pests and diseases, and promotes continuous increase in crop yields.
				Oryza sativa
			Tobacco–rice rotation	Nicotiana tabacum	Improve soil fertility, effectively eliminate farmland weeds and soil-borne pests and diseases, and promote sustained crop yield increases
				Ipomoea batatas
			Fish and duck farming in rice fields	none	Multiple uses of one field, multiple uses of one water, and multiple harvests in one season not only improve resource utilization efficiency and effectively save water and soil resources, but also improve soil permeability, increase soil fertility, and control rice diseases and insect pests.
			Terraced fields	none	It is the best agricultural production method for mountain people to make full use of local mountain resources to obtain agricultural products while conserving water and soil.
			Interplanting of Wogan and Peanut	Citrus reticulata	The waste from intercropping becomes organic matter for the growth of fruit trees after fermentation.
				Arachis hypogaea
			Macadamia and watermelon intercropping	Macadamia integrifolia
				Citrullus lanatus
	Diversity of agricultural culture	Traditional agricultural production depends on the natural environment, and the harvest after hard work is full of uncertainty. People pray to the gods for seeds and blessings through prayer ceremonies, which makes the uncertain agricultural production full of expectations. Therefore, many traditional cultures are preserved in the China–Vietnam border area, which promotes the protection of the local ecosystem.	Dabiandan	none	The Zhuang people’s Dabiandan activity originated from the labor of pounding rice. It developed from pounding rice to hitting the bench with a carrying pole. People beat the benches one after another in a staggered manner, demonstrating the Zhuang people’s transplanting, harvesting, threshing, and pounding rice. Local people of all ethnic groups pray to God for good weather, longevity, and good harvests through the “beating pole” activity.
			Niuhun Festival	none	On the eighth day of the fourth lunar month, farmers give their cows a day off. Each household repairs the cowshed and washes the cows. When the cows are bathing, they beat drums to cheer them up. The village elders comment on the cows in the village and warn each family to take good care of the oxen. Every family steams five-color glutinous rice and wraps it in loquat leaves to feed the cows. In some places, wine, meat, melons, and fruits are placed in the main hall as offerings. The head of the family leads an old cow around the offerings, singing as they walk, to praise and thank the cow for its merits. On this day, each household feeds the cow first, and then the whole family eats the festival meal. It shows the national ecological culture of an agricultural nation that cherishes oxen and protects productivity.
			Shuangjiang	none	Eating glutinous rice cakes during the Frost Descent season is an important custom of the Zhuang people. They use glutinous rice cakes as a high-quality sacrifice to thank nature, celebrate the harvest, express gratitude for the grace of nature, and pray for a good harvest.
Conservation and utilization of plant diversity	Protection and utilization of endemic plants	According to statistics in the literature, there are 3118 seed plants in the karst area of the China–Vietnam border in Guangxi, of which 294 are endemic to Guangxi. They are concentrated in the genera of Begonia, Aspidistra, Spirochaete, Primulina, and Staircase. Some of these endemic plants have the value of being edible, medicinal, ornamental, and building materials, and are widely recognized by the public and protected and used by local people.	Jingxi-nan	Phoebe jingxiensis	The wood is very hard and is used by local people to make furniture, house pillars, and beams. The root system is thick and strong, making it an excellent tree species for desertification control.
			Xianmu	Excentrodendron tonkinense	A plant endemic to tropical limestone, which can be used as various wood products, mostly in Longzhou
			Shiwanshanzhizhubaodan	Aspidistra shiwandashanensis	The leaves of the spider egg are often used to make rice dumplings. The steamed rice dumplings have a fragrant and pleasant aroma.
			Banliang-Yueju	Vaccinium bangliangense	Stone Mountain Greening
			Kuanyeyufenghua	Habenaria lindleyana	Plants in limestone areas
	Protection and utilization of ancient trees	In some streets and villages, many ancient trees have been preserved due to religious worship, and even a certain scale of “feng shui forest” dominated by a certain plant has been formed. For example, in Dongxing City, locals like five-color persimmon very much and call it hometown tree to ease homesickness. More importantly, in the past, food was scarce, and the fruit of this tree was mainly used to satisfy hunger. The oldest tree has now been preserved for about 500 years. According to the results of the second census of ancient trees and famous trees in Guangxi from 2016 to 2017, there are about 141,000 ancient trees and famous trees in the region.	Wuseshi	Diospyros kaki	Call it the hometown tree to ease homesickness
			Dayerong	Ficus altissima	Tolerant to drought and barrenness, strong winds, mostly in Jingxi
			Yuenanyoucha	Camellia oleifera	In Madong Village, Shangshi Town, Pingxiang City, there is a large ancient tea tree group that is rare in Guangxi and even in the country—736.5 acres and 8937 century-old tea trees.
Conservation and utilization of animal diversity	Habitat protection	Understand the food properties of white-headed langurs. The tender leaves, buds, flowers, and fruits of common trees such as paper mulberry, kapok, bamboo, peach, Trichosanthes kirilowii, dung beetle, and red sedge are the favorites of white-headed langurs. Therefore, they are deliberately planted in the buffer areas outside the nature reserve.	Baitouyehou	Trachypithecus leucocephalus	It is a species endemic to China. It is a first-class protected wild animal and a rare and endangered primate. It lives in the subtropical karst area with lush vegetation in southern Guangxi, China.
	Birdwatching economy	We have developed the bird-watching economy in a targeted manner, taking advantage of local conditions, and achieving the goals of increasing income, improving quality of life, and better protecting the ecology.	Nonggangsuimei	Stachyris nonggangensis	It is a typical karst bird, only distributed in the limestone areas of the karst mountains. In China, it is only distributed in the karst mountains in southwestern Guangxi.

), which shows that the residents of the China–Vietnam border area have relatively rich TEK, and local people have their own cognition and methods in environmental ecological management.

3.7. Optimization of Ecological Security System Combined with TEK

Based on the integrity and sustainability of the ecosystem, this study optimized the ecological security pattern of the China–Vietnam border region in Guangxi. TEK in this region is deeply rooted in the local communities’ adaptive strategies to karst landscapes, characterized by soil management techniques and biodiversity preservation methods that have been passed down for generations. Given the fragile karst ecosystem, local communities have developed customary ecological practices such as multi-layer agroforestry systems and sustainable grazing strategies, which contribute to maintaining ecological balance. Unlike conventional ecological security frameworks that rely solely on landscape ecology models, this study incorporates TEK-informed strategies to enhance the resilience and adaptability of ecological security patterns, ensuring alignment with both environmental characteristics and cultural sustainability. Therefore, based on the principle of “ecological restoration as the core, ecological protection as the basis, ecological corridors as the link, and TEK as the support”, the coordinated development of various natural elements is comprehensively considered. By integrating local TEK, such as afforestation, rotation and fallow, and biodiversity conservation, a multi-level and comprehensive “three axes, two belts, and six zones” ecological protection pattern is constructed (Figure 10).

The three axes refer to the “Napo South–Jing Southwest–Daxin–Longzhou–Ningming” ecological axis and the “Daxin–Longzhou–Ningming” east/west ecological axis. The three ecological axes pass through the patches with high resistance values in various counties and connect the ecological patches with long intervals, ensuring the circulation of species resources in the whole area, while ensuring the rational use of water resources, connecting the natural landscape and community development along the line, and upregulating the resilience and stability of the ecosystem.

The “two belts” are based on the “three axes” and supported by the “three axes”, connecting the two ends of the longitudinal ecological axis and the important ecological patches in the region. Three ecological axes and two ecological functional zones form regional ecological connectivity network, ensuring the upgrading of ecological responses and the integrity of the ecosystem. The six zones are divided into two types, such as protected areas and restoration areas. The protected areas are forest conservation areas, water conservation areas, karst ecological tourism areas, and species resource protection areas. The restoration areas include ecological function construction areas and cross-border ecological security restoration areas.

The forest conservation area is located in the western part of Napo County. Although the terrain is undulating, the vegetation coverage rate in this area is higher. The soil and water conservation capacity is strong, the habitat quality is good, and it has important ecological conservation functions. In fact, Napo County belongs to the Yunnan–Guizhou–Qianzhou rocky desertification area, and the rocky desertification is relatively serious. Local residents have been constantly trying to solve the industrial development problems in the border rocky desert and barren mountain areas. Through investigation, it was found that they have rich traditional knowledge in dealing with rocky desertification control. First of all, always respect nature and pay more attention to protecting the vegetation of “Houlong Mountain”, and then strengthen institutional guarantees by formulating village rules and folk agreements. Secondly, select native plants with strong adaptability, explore planting techniques based on plant characteristics, and enhance the plant survival rate efficiency. Finally, the combination of ecological and economic benefits, such as planting mulberry and raising silkworms, on the one hand, solve the economic source of the rocky mountain area, and at the same time, during the growth of mulberry trees, there are spring and autumn fellings every year. The mulberry stalks that are cut down can basically meet the current needs of the people for cooking with firewood, reducing dependence on mountains and forests. There is also a new model of managing rocky desertification by planting various types of bamboo on the hillside and developing industries, such as bamboo weaving and processing, which has broadened the channels for residents to increase their income.

The water conservation area is located in the middle and western parts of Fangcheng District, with a low altitude and high forest coverage. It has the world’s only national-level Camellia chrysantha Nature Reserve and the Beilun Estuary Reserve, the most contiguous and typical bay mangrove forest in the country. Coastal residents have a long history of protecting and utilizing mangroves and are very experienced in this. They know that protecting mangroves is also to protect the lives and property of fishermen. The intricate and developed root system of mangroves can effectively retain a large amount of silt input from rivers to the ocean, thereby reducing the sand content in the nearshore waters, effectively resisting attack by wind and waves, and protecting the lives and property of fishermen. Protecting mangroves is also to protect the production and lives of local residents. Mangroves have a wide range of uses. The fruit of Avicennia marina can be eaten directly as a dish after being boiled in water. Tung trees and lacquer are important resin-producing plants. The mangrove honey produced is light yellow, next only to litchi honey in quality and with a high yield. Moreover, the Beilun Estuary National Nature Reserve alone has recorded 250 bird species, of which 209 are migratory birds, accounting for 83.6% of the total number of birds. Based on their long-term interactions with water birds, the locals have consciously created habitats and breeding grounds according to the needs and habits of different water birds. Therefore, local residents are familiar with the characteristics of water birds and are the best bird-watching guides. Through tourism, their professional skills in identifying, guiding, and finding birds have been significantly improved. Most importantly, through the promotion of economic sources, their awareness of spontaneous bird protection has also increased, and mangroves have been protected as a result.

The species resource protection area is located in the middle and southern parts of Ningming County. In terms of the natural geographical environment, the Zuojiang River Basin is located in the semiarid monsoon climatic zone, which is characterized by a mild climate, abundant sunshine resources, and abundant precipitation, providing excellent growth conditions for subtropical plant communities. This ecological environment has nurtured lush vegetation and attracted many animal species to live and reproduce here, thus forming an ecosystem with rich biodiversity. There are many rare animal and plant species, such as white-headed langurs, broad-leaved jade flowers, and clam wood. At the same time, this natural environment provided food resources for early residents, including directly collected plant fruits and rhizomes, as well as wild animals for hunting. Therefore, local people have rich knowledge and wisdom about the protection and utilization of species resources. One example of this is clam wood: with excellent materials, long life, and strong adaptability to the karst limestone environment, many giant clam wood trees are completely preserved in Ningming County, of which there are four individual trees with a history of more than 1000 years. They are recognized as a group of the oldest ancient trees in Guangxi, and the oldest tree is regarded as more than 2300 years old.

The karst ecotourism area is located in Longzhou County, a major border trade town. There is the Guangxi Nonggang National Nature Reserve (hereinafter referred to as the Nonggang Reserve) at the junction with Ningming. Because the natural resources are relatively rich, but the land is relatively scarce, in fact, the residents’ intensity of natural resource utilization is very high. Therefore, in order to protect the environment while taking into account the development of the residential community, the government and residents have innovated a participatory management model to jointly build a nature reserve. The bird-watching economy has produced great economic and social benefits. Through bird-watching tourism, villagers can obtain considerable income, and the related plant resources related to the spread and reproduction of birds will also be protected, reducing dependence on forest nature. By the end of 2023, 1422 people from 344 households in 10 villages and towns around the reserve had participated in bird-watching and photography services or engaged in related services, more than 20 bird-watching homestays have been built, and more than 40 bird-watching guides have been produced, forming a unique bird-watching industry economic belt in the reserve, which is called a new model for the green revitalization of rural areas in Guangxi.

The cross-border ecological security restoration area is located in Pingxiang City and the northern part of Ningming County. The area is an important border trade town with high ecological resistance and low habitat quality. The frequent logistics activities of trade channels, such as Pingxiang Port and Youyiguan Port, have exerted great pressure on the local environment. A large number of anthropogenic activities, including infrastructure construction, farmland development, and industrial production, have led to the over-exploitation of land resources in the region, destroyed natural vegetation, and increased the burden on the ecosystem. With the further development of the border economy, the potential risk of ecological damage has also increased, making the ecological security risk high. Therefore, in the case of more mountains and less land, we should vigorously develop intercropping technology; intercrop watermelons, vegetables, and other short-term crops and Chinese medicinal materials between the main crop sugarcane fields and young nut orchards; and use the short to support the long. The waste from intercropped crops does not need to be recycled. After fermentation, it becomes organic matter for the growth of plantations. Therefore, this method is the best agricultural production method for mountain people to make full use of local mountain resources to obtain agricultural products while maintaining water and soil.

The ecological function developmental area is located in the middle part of Jingxi City. Jingxi is a gathering area for the Zhuang nationality. A total of 98% of the city’s population are of Zhuang nationality. The area has preserved a relatively complete Zhuang culture, so it is also one of the areas with the richest ecological farming culture. In fact, with the influence of industrialization, urbanization, climate and environmental changes, changes in agricultural production methods, and scientific and technological progress, the speed of variety renewal is accelerating. Many new varieties with high yields, good quality, and excellent comprehensive traits are constantly emerging, and many old varieties are on the verge of extinction. However, in Jingxi, excellent local varieties, such as Jingxi-Daxiangnuo and Jingxi-Damaya are still preserved. Jingxi-Daxiangnuo has a planting history of more than 800 years and has been a tribute for generations. According to the survey, there are at least six varieties in the local area, with relatively rich genetic resources, which provide valuable experimental materials for glutinous rice research. In addition, Jingxi-Damaya is an excellent poultry variety resource with unique economic traits, strong stress resistance, and roughage resistance that is adapted to the local environment. These old varieties have strong adaptability, good stress resistance, excellent quality, and carry a large number of excellent genes. They are an important foundation for supporting breeding innovation and industrial development, and have played a major role in upgrading agricultural production and meeting people’s needs. In addition, Jingxi’s agricultural ecosystem is also diverse, with rice fields that can be used for multiple purposes, such as raising fish and ducks, terraced fields with multifunctional ecological functions, and tobacco–rice rotation farming models that improve soil ecology. Therefore, the Jingxi region should rely on its rich natural landscape and cultural resources, give complete play to the value of ecological culture, improve the ecosystem service function, and upregulate the sustainable development of border areas.

4. Discussion

4.1. Role of TEK in Karst Landform Ecological Protection

Due to its unique geological characteristics, the karst landform in the China–Vietnam border region of Guangxi faces serious ecological vulnerability problems. For a long time, residents living in the area have accumulated rich experience and technology through TEK to help cope with these ecological challenges. These traditional ecological practices are not only an important part of local livelihoods, but also provide an important reference for the development of a modern ecological security system.

First, the traditional rotation and fallow system has a significant impact on the prevention and control of soil degradation. Since the soil in the karst area is shallow, rotation and fallow can avoid excessive land reclamation and promote the recovery of soil nutrients [48]. The integration of practices such as “tobacco–rice rotation” with modern ecological restoration technologies has shown promising results in improving soil productivity and reducing erosion, directly contributing to sustainable land management practices. Secondly, afforestation and vegetation restoration are important means of traditional ecological management in karst areas. Local residents have increased the stability of the ecosystem by choosing native drought-resistant vegetation, cash crops, and multi-layer bottom planting. These practices align with global goals of land restoration, such as the targets set in the United Nations Sustainable Development Goals (SDGs). In addition, terrace farming technology is widely used in karst areas. By building terraces, residents have effectively controlled the speed of water flow and reduced soil erosion in the mountains. This technology not only improves land use efficiency, but also provides more favorable conditions for the development of ecological corridors by transforming the terrain. Integrated with traditional terrace farming technology, the design and management of corridors can be further optimized to increase the connectivity and functional stability of the ecosystem. The principles of TEK-based ecological security patterns observed in the Guangxi–Vietnam border region can be extended to other karst landscapes with similar ecological challenges. In Southwest China, for example, local communities have implemented agroforestry systems and soil stabilization techniques to mitigate the effects of karst rocky desertification. Jiang et al. (2022) highlight how targeted vegetation restoration strategies, informed by traditional ecological knowledge [49], have significantly improved soil stability and enhanced ecosystem services in degraded karst regions.

4.2. TEK in Cross-Border Ecological Protection

In the Guangxi–Vietnam border region, ecological protection of karst landscapes requires not only integrated management but also collaborative efforts between the two countries. The region’s complex ecological environment, characterized by high biodiversity and ecological vulnerability, calls for joint actions to protect key species and maintain ecosystem connectivity and stability.

First, the protection of white-headed langurs (Trachypithecus leucocephalus) has become one of the focal points of cross-border ecological cooperation between China and Vietnam. The white-headed langur is an endangered species primarily distributed in the karst forests of Guangxi and northern Vietnam, playing a critical role in maintaining ecological balance in these habitats. Both countries have established nature reserves, restored habitats, and mitigated human disturbances to significantly improve the survival conditions of the species. Additionally, local communities have contributed to habitat protection by leveraging TEK, such as restricting hunting and preserving forest integrity. The integration of local practices with modern conservation measures not only facilitates the survival of the white-headed langur, but also provides an exemplary case for biodiversity conservation in cross-border contexts. These approaches align with our study’s findings, demonstrating that TEK-driven ecological management is not only effective in localized contexts, but can also serve as a model for broader ecological security planning in similarly vulnerable landscapes.

Second, communities on both sides of the border have long depended on forest and farmland resources, maintaining ecosystem balance through traditional forest management practices such as limited logging and fallow rotation. These methods ensure the sustainable functioning of forest and agricultural ecosystems while minimizing human-induced damage to ecological corridors. By integrating these traditional practices, the two countries can establish more connected and adaptive ecological corridors in the karst region, facilitating the cross-border migration of plant species and ensuring habitat sustainability.

The cultural consensus on cross-border ecological protection serves as a crucial foundation for the coordinated implementation of ecological protection policies in both countries. Through centuries of ecological adaptation, the border regions have developed shared ecological values and environmental ethics. For instance, the Zhuang people in Jingxi City, Guangxi, revere forests as “sacred groves”, attributing them with sanctity and inviolability. This tradition has fostered a strong sense of forest conservation, with local communities prohibiting tree felling and wildlife hunting, thereby preserving forest ecosystems. Similarly, ethnic minority communities in northern Vietnam view forests not only as sources of livelihood but also as habitats for ancestral spirits. Groups such as the Tai and Yao rely on their TEK to live harmoniously with nature, employing practices like selective logging to maintain ecological balance [50,51]. This profound respect for nature, coupled with long-standing conservation practices, provides a vital cultural basis for cross-border ecological cooperation in the border regions. In these border regions, economic development lags. Due to similar ecological environments, customs and traditions in both countries share many similarities. Urban planning should highly value applying traditional ecological knowledge. This not only greatly aids ecological conservation but also promotes cross-border community integration by respecting and learning from local cultures. Eventually, it will boost the sustainable development of the China–Vietnam border areas and strengthen friendly relations. The shared ecology and cultural affinities form a solid basis for closer cooperation in ecological protection and regional development.

4.3. Limitations and Development of TEK in Ecological Applications

While traditional ecological knowledge has demonstrated significant potential in ecological protection and management [52,53], its application in constructing ecological security patterns and other large-scale ecological studies faces several challenges and limitations.

The intergenerational transmission of traditional ecological knowledge is under significant threat as rapid urbanization, cultural shifts, and economic development distance younger generations from traditional practices, weakening its continuity. Among 326 respondents, only 10 individuals aged 15–25 were familiar with TEK related to their lives, accounting for just 3.6% of all respondents and 31.3% of their age group. TEK awareness increases with age, highlighting the fragility of its intergenerational transmission and the younger generation’s declining engagement with traditional culture. This decline challenges the integration of TEK into modern ecological frameworks, as the loss of experiential knowledge reduces its applicability in ecological management and governance. It also undermines local communities’ cultural identity and capacity for self-managed ecological protection. In karst region conservation, the urgent priority is to combine modern education and technology to protect and revitalize TEK, bridging the gap between traditional and modern ecological practices and ensuring TEK’s effective transmission across generations. Urban environments pose unique challenges for preserving traditional ecological knowledge Rapid development, industrialization, and shifting livelihoods often leave little room for traditional practices. Unlike rural communities, where TEK is woven into daily life, urban settings offer fewer chances for hands-on engagement with ecological traditions. To address this, strategies could include introducing TEK concepts into school curricula, incorporating traditional practices into urban green spaces, and creating platforms for indigenous voices in urban planning and sustainability initiatives. Additionally, government-led initiatives could provide funding for TEK-based ecological projects and offer incentives to encourage TEK practitioners to collaborate with urban planners, ensuring that traditional knowledge is incorporated into sustainable city planning. Beyond education, legislative measures can also play a key role in ensuring the long-term preservation of TEK. Strengthening environmental regulations that recognize TEK as a valuable resource for sustainable development can promote the integration of TEK into ecological management policies. For instance, policies could support community-driven conservation programs that reward TEK-based land use practices, ensuring that traditional knowledge contributes to sustainable economic activities while preventing environmental degradation.

Second, many aspects of TEK are inherently localized and specific to certain communities or ecosystems, making it difficult to incorporate them effectively into large-scale ecological studies or regional-level ecological security pattern construction. For instance, practices rooted in localized cultural or environmental contexts may not align with the standardized methodologies required for broader spatial analyses. This mismatch highlights the need for innovative methods to bridge the gap between localized knowledge systems and the requirements of large-scale ecological research. From a policy perspective, the integration of TEK into ecological security planning would benefit from improvements in legislation regulating economic activities in ecologically sensitive areas. Policies that incentivize TEK-based sustainable resource management, such as community-led forestry, water conservation, and agroecological farming, could help align economic development with ecological conservation. Introducing targeted subsidies, tax incentives, or certification programs for industries and communities that incorporate TEK practices could encourage broader adoption of traditional ecological strategies while promoting sustainable livelihoods. Moreover, stricter environmental regulations on land use and extractive industries in TEK-rich regions could prevent further ecological degradation and ensure the continued relevance of traditional ecological practices in modern governance frameworks.

Finally, although TEK offers practical insights and sustainability principles, its integration with modern ecological frameworks often requires adaptation. Balancing the qualitative and context-specific nature of TEK with the quantitative, generalizable demands of large-scale ecological studies remains a key challenge. However, advances in interdisciplinary research, participatory approaches, and the use of digital tools for documenting and mapping TEK present opportunities to overcome these barriers.

In the future, addressing these challenges will require collaborative efforts to preserve and revitalize TEK while finding ways to adapt it for broader ecological applications. Strengthening community engagement, investing in TEK documentation, and fostering cross-disciplinary collaborations are essential steps to fully unlock TEK’s potential in ecological security pattern construction and sustainable development. Integrating TEK into legislative frameworks and formal educational programs will further enhance its role in shaping ecological policies, ensuring that traditional knowledge continues to contribute to global sustainability efforts.

5. Conclusions

The ecological security pattern of the Guangxi–Vietnam border region was developed by integrating ecosystem service functions and environmental sensitivity assessments. The study identified key ecological elements, including 55 ecological corridors (totaling 2273.51 km), 80 ecological pinch points, and 14 ecological barrier points, which are primarily concentrated in human-disturbed areas and require targeted conservation efforts. The results highlight the limited ecological source area (7.4% of the region) and the importance of enhancing connectivity to improve ecosystem stability and species migration channels.

By integrating traditional ecological knowledge, the study established an optimized ecological security framework (“three axes, two belts, and six zones”), enhancing ecosystem connectivity and offering innovative insights for sustainable ecological management. This study demonstrates that integrating TEK into ecological security planning enhances regional conservation strategies and supports sustainable land use management. Policymakers can apply TEK-based approaches to biodiversity conservation and ecological restoration, strengthening ecological resilience. Beyond the Guangxi–Vietnam border, this model provides a reference for similar karst and transboundary ecosystems facing ecological degradation. Future research should focus on scalable frameworks that integrate TEK with modern ecological management to ensure long-term sustainability.