1 Introduction
China's Xizang border area borders Nepal, Bhutan, India, Myanmar, and Kashmir. The borderline is more than 4000 km long, which is the most complicated area in China's border situation. There are 21 border counties, 163 townships, and 628 villages in Xizang, with a total land area of 380,800 km
2, accounting for 31.67% of the region's land area, and an average population of more than 15,000 people. Due to the long-term constraints of complex geopolitics, sensitive ecological environments, and weak economic foundations, although the construction of border settlements has achieved certain results, it still faces many challenges: the contemporary translation ability of traditional construction wisdom is still relatively weak (
He, 2022). Although the border population has shown an increasing trend, there is still a problem of sparse population to a certain extent (
Zhu and Zhang, 2022). Based on this, how to excavate and sort out the excellent construction experience in the historical space of the Xizang border area, combine it with modern technology, establish a scientific and reasonable technical method for the construction of human settlements in the border area, and realize the contemporary translation of its construction experience is an urgent problem to be solved. At present, the development of human settlements is a hot topic in the world. However, the related research on the content composition and inheritance mechanism of the settlement's living environment mainly focuses on the interaction mechanism between its spatial construction and natural system (
He and Wang, 2005;
Li et al., 2016;
Mitchell et al., 2024). The research on the impact of comprehensive security needs such as land, ecology, society and culture on the construction of human settlements has not yet been carried out, and the essence of its spatial material form has not been revealed. As a new theoretical technology in recent years, spatial gene has initially formed a set of theoretical methods. Spatial gene is defined as “some unique and relatively stable spatial combination patterns formed in the interaction between urban space and natural environment, history and culture.” It is based on the construction concept that is more conducive to local survival and development, encodes the spatial elements into a specific configuration relationship, stores, transmits, and expresses the settlement information containing the local construction concept at that time, and controls and affects the evolution and development of the settlement space form. Specifically, it includes three characteristics of material, hierarchy, and information: 1) Material aspect. Spatial genes present a specific spatial element configuration relationship in space; 2) Level. The spatial gene exists in various spatial levels such as settlements, neighborhoods, plots, and buildings; 3) Information. The space gene contains urban information adapted to local survival and development at that time (
Duan and Shao, 2019;
Jiang et al., 2025). This theory has also been initially introduced into settlement research. The existing research results have proved that the technical application of spatial gene theory can take into account the development needs of society, ecology, humanities, history, and so on in space construction, and has a wide range of application and promotion potential. However, how to combine spatial gene theory with human settlement science and introduce it into the study of border settlements in Xizang is still rare.
Based on this, considering that the border settlements in Xizang are an integrated system of ecology, human settlements, and social coordination, and have the characteristics of a small population, small scale, and sparse distribution. It is difficult to accurately explain the composition of construction experience and the dynamic mechanism of inheritance in its historical space if it is cut from a single perspective or from macro and meso scales. As a basic concept commonly used in modern science and technology systems, “unit” can clearly understand and control the functional elements of the system organization according to the established objectives. Therefore, based on the ontological characteristics of border settlements in Xizang, combined with the theory of human settlement environment, spatial gene, and the overall national security concept, the concept of “border settlement human settlement unit” is proposed, which is defined as: at the level of a land space system, it is a comprehensive system composed of ecological security space unit, human settlement security space unit, and social security space unit. Among them, the ecological security space unit specifically includes landscape space, climatic conditions, and farming space, and the human settlement security space unit specifically includes settlement space, road space, and architectural space; social security space includes production mode, social structure, and value cognition. The construction wisdom of this living unit is reflected in its spatial genes, and the inheritance of construction wisdom is realized through the coding, replication, and expression of spatial genes (Fig. 1). In this study, Kejia Village, Pulan County, Ali, Xizang was selected as an example. The spatial gene map identification method, spatial morphology analysis method, and element extraction method were combined to analyze the content composition of the settlement living unit that is beneficial to land security, green development, and cultural inheritance, and to reveal its inheritance mechanism, so as to provide a reference for the safety construction, ecological construction and green living construction practice of Xizang border settlements.
2 Literature review
2.1 Research on the content composition and inheritance mechanism of human settlements environment
After World War II, Greek architect C.A. Doxiadis put forward the theory of “human settlement” (EKISTIC), which aims to effectively promote the construction of human settlements. With the convening of the first UN
Habitat Conference (1976), Rio de Janeiro Environment and Development Conference (1992), Istanbul + 5 Habitat Special General Assembly (2001), and other conferences, the study of human settlement's development has become a proposition of concern to the world.
In China, the study of human settlements in the true strict sense began with the concept of human settlement's science, which is a science that focuses on human settlements (including villages, towns, cities, etc.) and focuses on the relationship between human and environment (
Wu, 2010). The research on the human settlement environment contains rich content, which is introduced from two aspects: content composition and inheritance mechanism.
2.1.1 Relevant research on the content composition of human settlement's environment
In the related research, the typical research scales include macro (country), meso scale (region and town), and microscale (urban water system, rural settlements, and buildings). Among them, there are many studies on meso-scale. Representative studies such as
He and Wang (2005) proposed the concept of a “basic human settlement ecological unit” by drawing on the research results of biology, landscape ecology, and other disciplines. The research on micro-scale is mainly aimed at rural settlements and buildings. Among them, the research on rural settlements includes
Zhang (2019a), based on extensive research, explained the four components of rural landscape: regional characteristics, place landscape, pastoral environment, and social humanities. Based on the theory of landscape genes, extracted the environmental, overall, and local characteristics of desert oasis settlements. The research on architecture includes:
Song et al. (2020) analyzed the green construction experience of traditional dwellings in Qinghai and other places from the perspective of building energy consumption.
Mitchell et al. (2024) based on a quantitative analysis of Phoenix, Arizona, explored the impact of the interaction between urban space and ecological nature on the physical and mental health of residents.
In summary, in the study of the content composition of the living environment, the overall focus is on the interaction mechanism between space construction and natural systems.
2.1.2 Relevant research on the inheritance mechanism of human settlements environment
Existing research mainly intervenes from the perspectives of geography and historical geography, ecology, and space. Among them, the research from the perspective of space is mostly. In the study of space, the main research objects are villages and communities. Among them,
Zhang (2019b) used remote sensing technology to explain the evolution mechanism of rural settlements in multi-ethnic areas.
Lei et al. (2022) used morphological indicators and spatial syntax to reveal the spatial characteristics and development mechanism of Miao traditional villages in Southeast Guizhou.
Gao et al. (2023) explained the spatial evolution mechanism of typical villages along the Yangtze River by combining spatial analysis and anthropological fieldwork research methods.
It can be seen that the research on the inheritance mechanism of human settlements from the perspective of space has become the current academic hotspot. Previous studies mainly used methods such as system theory, topological geometry, fractals, and space syntax to reveal the experience inheritance mechanism of creating a rural settlement living environment.
2.2 Study on the application of spatial gene map in a human settlement environment
As a new theoretical technology in recent years, spatial genes have initially formed a set of theoretical methods. The application of this theory in the field of human settlement environment is mainly introduced from two aspects: its theoretical application and technical practice.
2.2.1 The study of spatial gene theory
In 1942, American geographer
Griffith (1942) first introduced genes into the field of settlement research, explored its core landscape factors by comparing the spatial structure of settlements and created a new method of settlement research. British scholar
Conzen (1988) used the theory of botany to extract the common genes of morphology and structure in ancient town settlements and then studied the spatial form of towns through cultural genes. On this basis, scholars of urban morphology use the concept of spatial hierarchy to further describe the order of settlement patterns (
Marshall et al., 2018). It is the core issue of various urban morphological methods, especially historical geography (
Whithhand, 2001) and process typology (
Caniggia and Maffei, 2001), and is widely used to analyze the formation and transformation of settlement patterns. Based on the existing research results, Gauthiez further abstracted the configuration relationship of settlement space from the physical space form and tried to extract its morphological genes (
Gauthier, 2004).
Chinese scholars have carried out relevant explorations on this basis.
Liu (2003) first applied the theory of cultural genes to the study of spatial form, put forward the concept of “landscape gene”, and combined it with typological methods to study the cultural landscape flora of traditional settlements. Then, inspired by the cartographic graphic method,
Shen et al. (2006) applied the gene map theory to the study of traditional settlement landscape flora and summarized and integrated the graphic method of traditional settlement landscape structure. In recent years,
Duan and Shao (2019) put forward the theory of “spatial gene” from the perspective of urban spatial development theory, and emphasized that the theory can realize the interaction between spatial elements and natural environment, social needs, history, and culture, and further put forward the technical system of “identification-analysis-inheritance” spatial gene, and answered the question of how to identify, refine and present the characteristics of spatial structure (
Shao et al., 2020). The proposal of space gene borrows the concept and principle of “gene” in biology. Danish botanist Johanson coined the term “gene” to refer to the genetic information carrier that determines the traits of the organism, which stores all the information that guides the process of breeding, growth, and apoptosis of the organism (
Mukherjee, 2016). Accordingly, the spatial gene is the information carrier that controls the spatial form of the material and stores the key information that dominates the evolution and development of the spatial form of the settlement. The commonness between spatial genes and biological genes is that they are both regarded as information carriers to guide the survival and development of the ontology. The difference between the two is that the biological gene is an objective existence, and its basic unit is the nucleotide sequence; the spatial gene is an abstract pattern, and its basic unit is the spatial elements and their configuration relations. In addition, the genes extracted from any level of the organism are exactly the same, and the spatial genes extracted from different levels of the settlement are different due to the different relationships between their constituent elements and elements (Fig. 2).
Since then, the research content of spatial genes has been continuously discussed based on different disciplinary perspectives. One is to study. cultural landscape genes from the perspective of geography, focusing on the logic of gene identification, extraction, and inheritance behind cultural landscapes (
Li et al., 2024); the second is to study spatial morphological genes from the perspective of planning, and using morphological typology to measure specific genes to explore the factors that control spatial morphology (
Zhao et al., 2021); the third is to study the architectural culture gene from the perspective of architecture, express the architectural features around the single building by using descriptive indicators, and focus on the genetic inheritance characteristics under the regional construction system (
Wang et al., 2008). In the study of settlements,
Qin (2024) tried to study the whole process of description and classification-identification and extractionatlas expression-protection and inheritance of the spatial genes of Xizang traditional villages in Gannan.
2.2.2 Research on the practical application of space gene technology
At present, space gene technology, as a new technical means, is still in its infancy. Its technology is mainly used to guide the overall design of the city, as well as to coordinate regional development and cultural heritage (
Shao et al., 2020). Among them, in terms of coordinating regional development and cultural inheritance, the typical cases of practical application of this technology include urban design such as Xiamen, characteristic villages and towns in the middle and lower reaches of Minjiang River Basin, and historical and cultural blocks in Chengdu. The existing research results have proved that the technical application of spatial gene theory can realize the localization of urban construction design, take into account the development needs of society, ecology, humanities, and history in space construction, and have a wide range of application and promotion potential. However, there are still considerable vacancies in existing cases and practical experience.
2.3 Research review
In summary, the research on the content composition and inheritance mechanism of human settlements and the application of spatial gene theory in the field of human settlements have made important progress, but there are still some shortcomings.
In terms of research objects, although some of the previous studies have long involved traditional settlements in Xizang areas, such as traditional Xizang villages in Gansu (
Qin, 2024), there is insufficient attention to Xizang border settlements located in remote high-altitude areas with ecological, cultural and ethnic characteristics.
In terms of research content, first of all, previous studies have mainly focused on the perspective of the interaction mechanism between space construction and ecological nature, but the research on the impact of security needs, especially comprehensive land, ecology, society, culture, and other security needs on the construction of human settlements has not been carried out. Secondly, the existing research on the composition of human settlements mainly starts from the meso-scale, and the research on the micro-scale level still needs to be enriched.
In terms of research methods, first of all, previous studies mainly used methods such as system theory, topological geometry, fractals, and space syntax to analyze the spatial evolution mechanism of human settlements, but the nature of its spatial material form was insufficiently discussed. The spatial gene theory can realize the interaction between spatial elements and the natural environment, social needs, history, and culture, and has a wide range of technical applications and promotion potential. Therefore, considering the particularity and complexity of Xizang border towns, how to combine the science of human settlements and the theory of spatial gene map to introduce the research field of Xizang border towns is still lacking in experience and achievements. The above deficiencies are also the breakthrough of this study.
3 Research methods
3.1 Case study
The selection principles of research cases are as follows: First, in the study of Tibetan social anthropology, settlements on the main trade routes are often regarded as typical research objects, because they are often the epitome of regional economic structure and social stratification (
Aziz and Barbara, 1978;
Dargyay, 1982). Second, considering the deep embedding of religion in Tibetan social structure, cultural identity, and daily life, elements with monasteries are also the main focus of previous studies (
Samuel, 1993;
Schendel, 2002). Third, considering the historical stratification characteristics of traditional settlements, to systematically analyze the construction wisdom of Tibetan traditional settlements, it is necessary to keep the historical pattern intact as a necessary condition for research. In addition, according to the distribution of Xizang border villages (Fig. 3), the Ali border area is an important part of the Xizang border system. Although the distribution of settlements in the border area is sparse, it is the residence of 34 ethnic groups such as Tibetan, Han, and Mongolian. It is also the ecological core of international rivers such as the Yarlung Zangbo River, the Indus River, and the Ganges River. It is also a cross-civilization belief center. Therefore, the strategic position, national defense value, and development significance of its settlement construction play an irreplaceable role in China's borderland governance.
Based on the above principles and actual conditions, this study selected the Kejia Village in Pulan County, Ali as the research object. Kejia Village is not only a salt and grain border trade hub since ancient times, but also the seat of the temple Kejia Monastery of believers in China, India, and Nepal. The historical pattern of Kejia Village is relatively intact, and the architectural relics such as temples and dwellings are retained. In addition, Kejia Village is also a relatively concentrated area of population in the Ali border area of Xizang, a major planting area and an important border channel (Fig. 4). Therefore, Kejia Village has certain typicality, representativeness, and feasibility in the study of the construction wisdom and inheritance mechanism of settlement living units in the border areas of Xizang.
3.2 Data sources
The data of this study include spatial information data, meteorological data, interview data, historical data, image data, social and economic data, etc. In the spatial information data, the contemporary data comes from July 2–27, 2024. Using UAV aerial photography, on-site surveying and mapping, and CAD plane drawing, the village layout, internal roadway, surrounding roads building distribution, and other information are obtained, and the DEM digital elevation data with a spatial resolution of 30 m is downloaded in combination with the geospatial data cloud platform. The modern spatial information data are based on the keyhole satellite map of 1973 (resolution: 6 m, shooting date: 1973, satellite system: KH-9, location: Xizang, Kejia Village, single scene area: 160×270) as a reference, and based on the mapping of modern and modern residential buildings obtained by field investigation. In terms of spatial information data of early settlements, because there are no historical documents and historical images such as village records and family genealogy in Kejia Village, the spatial information of early settlements is pushed and depicted based on existing topographic maps based on the interview records of elderly villagers obtained during field visits. The meteorological data are derived from the typical meteorological year (TMY) data, and the data format is CSWD (Chinese Standard Weather Data). The enthalpy-humidity diagram is generated by reading the meteorological data of Ali, where the Kejia Village is located, through Climate Consultant software.
The interview data come from the research team, with the assistance of the Cultural Relics Bureau of the Xizang Autonomous Region and the Cultural Relics Bureau of Plan County, in the form of semi-structured interviews, following the procedure of “sample village → sample village committee → sample household → individual”. A total of 32 households from 15 households in Kejia Village were interviewed. The interview outline mainly focuses on the interviewees' selection of the characteristic space of Kejia Village, cognitive ranking, related life production, and belief legends. Other historical, interview, image data, and socioeconomic data are obtained through field investigation.
3.3 Research method
This study combines the literature research method, field investigation method, semi-structured interview method, spatial gene map identification method, spatial form analysis method, etc., with the help of the GIS platform to integrate the spatial data and attribute information of the residential units in Xizang border towns and follow the logic of “theoretical exploration-conceptual model-expression model-analysis model-conclusion interpretation” one by one, to explore the construction wisdom and inheritance mechanism of the residential units in Xizang border settlements in China.
Firstly, the spatial form data set of Kejia Village, a typical Xizang border settlement living unit, is created in the GIS system, and the attribute information such as production, society, and culture is collected to establish a spatial information database. Furthermore, the development and evolution of the typical border settlement unit Kejia Village are divided into stages. After that, the spatial form and structure of the settlement space of the early, modern, and modern Kejia Villages, as well as the maps of modern and modern residential buildings, are vectorized. Taking the historical maps of the above stages as parameters, the spatial pattern of Kejia Village, a typical border settlement living unit in different stages, is explained. According to the three subsystems of ecological security space, human settlement security pace, and social security space, the evolution path of its spatial pattern is explained. Then, using the combination of qualitative and quantitative analysis methods, through the four steps of combing the characteristic space-obtaining the public's characteristic cognition of the characteristic space-clustering and screening the spatial features-abstracting the configuration relationship of the spatial elements, the spatial gene elements and their index system are identified and extracted, and the spatial and temporal pedigree of the spatial gene is established. In order to identify the adaptive characteristics of spatial forms in different periods, analyze the evolution mode and influencing factors of spatial genes of typical border settlements, and reveal its inheritance mechanism (Fig. 5).
3.4 Research hypothesis
According to the above-mentioned combing characteristic space to obtain the public's cognition of the characteristics of the characteristic space-clustering and screening of spatial the configuration relationship of abstract spatial elements, this spatial gene recognition extraction and map construction ideas (Fig. 6), combined with previous research results (
Kostof, 1991;
Oldeld, 2009;
Zhou et al., 2024). In this study, a spatial gene recognition framework of “genome-gene-feature factor” was constructed. Five elements covering macro, meso, and micro landscape patterns, human pattern, settlement structure, road network structure, and architectural space were selected to form the genome, and 10 genes and 14 characteristic factor indicators were refined. Qualitative and quantitative methods were combined to jointly construct a spatial gene extraction index system (Table 1).
4 Analysis
4.1 Historical stages of spatial form evolution of human settlement unit
There is an objective historical stage in the construction and development of a human settlement unit in Kejia Village. By combining the change process and important events of the social, cultural, and economic system of Kejia Village, a multi-scale timeline was established at the two levels of Xizang border settlements and Kejia Village (Table 2). Through the qualitative evaluation of feedback between events and processes of different scales, the key factors of system changes and the key nodes of spatial form changes are identified (Fig. 7).
The construction of Kejia Village began with the construction of Kejia Monstery (AD 996). With the settlement of believers, the prototype of Kejia Village centered on Monstery appeared, which initially formed the settlement space form of Kejia Village and continued for a long time under the feudal serfdom social system (
Sun, 2020). After 1959, the redistribution of land resources and means of production drove the reconstruction of living space and production space in Kejia Village (
Cai, 2021). This change has made a major change in the spatial form of Kejia Village; after 2000, Kejia Village was included in the key area of Xizang's strategy of actively developing border trade towns. It is positioned as a culturally characteristic village. To expand the cultural influence of Kejia Monastery and the growing demand for external transportation, the spatial form of Kejia Village has once again changed.
4.2 The evolution characteristics of spatial form of human settlements unit of Kejia Village
From the three constituent systems of human settlements: ecological security, human settlement security, and social security, the evolution characteristics of the spatial form of human settlements are analyzed one by one. Among them, the ecological security space system includes three parts: landscape space, climatic conditions, and farming space. The human settlement's security space system includes three parts: settlement, road, and building space. The social security space system includes three parts: livelihood mode, social structure, and value cognition.
4.2.1 Evolution of ecological security spatial form
In terms of landscape space, Kejia Village is surrounded by the Gangdise Mountains the Himalayas, and the Peacock River are adjacent to the west side of the village. It not only has relatively fertile soil, grassland, and abundant water resources but also continues to face the ecological risks of flash floods and debris flows (
LCCCT, 2011).
In terms of climatic conditions, Plan County of Ali belongs to the arid climate zone of the plateau sub-frigid zone, dominated by cold and drought, which is in line with the cold and arid climate (Bwk) in the Köppen-Geiger climate classification, superimposed on the vertical variation of the highland climate (H), forming an extreme environment with low temperature, strong radiation, less rain, and more wind. From 1970 to 2020, the average temperature in Pulan County, where Kejia Village is located, showed a significant increase trend, with a warming rate of 0.04 ºC/year, and the total annual evaporation showed an increasing trend. The annual precipitation showed a decreasing trend, resulting in a continuous decrease in water resources.
In terms of farming space, in the traditional stage, the flat valley area of Kejia Village was used as a farming space. However, due to the long-term feudal serfdom society of political and religious integration, monks, and aristocracy, the development of productivity was slow, making the farming space relatively scattered. After 1959, the hierarchical land tenure system was abolished, and the farming space of Kejia villagers changed from farmland in the back mountain to farmland in the gentle slope of the foothills. After the 1970s, mechanical farming was introduced, and the distribution and volume of farming space were transformed through the construction of water diversion facilities.6 Cultivated land was gradually concentrated to the foothills and flat valleys (PYCC, 2017). In order to maximize the use of water resources, by 2016, the main cultivated land in Kejia Village had migrated to the east bank of the Peacock River (
Cai, 2021).
4.2.2 The evolution of human settlements security space form
In terms of settlements, roads, and architectural space, after the completion of the Kejia Monastery, some of the worshippers who came to worship chose to stay in the caves on the slopes around the Kejia Village Monastery. Only monks and nuns, officials, heads, and some wealthy families built houses next to the temple hall (
Wang et al., 2017). In addition, RinchinSambu, the presiding officer of the Kejia Monastery, was granted a fiefdom by the King of Pulan, and the three fiefdoms near Tsarwa was used as its “Xika” (manor), which is also the earliest record of a feudal lord's manor in Xizang to date. At this stage, the settlement road space system consists of three turning circles: the inner circle surrounds the Juekang Hall of the Kejia Monastery, the middle circle surrounds the temple, and the outer circle surrounds the residential area. The spatial form of residential buildings presents three forms: independent type, manor type, and cave type. In the transitional stage, as the residents moved to the gentle slope and the bottom of the mountain, a new group of residential space and a belt-shaped settlement structure were formed along the sunny slope, and a multi-story civil structure was newly built. After the 1970s, a large number of houses in Kejia Village were renovated, and the multi-storey blockhouse houses with stone and wood structures began to be updated from civil structures. In the modern stage, the residents around the temple began to move to the valley plain and along the street, and multi-story dwellings with concrete structures appeared (Fig. 8). Thus, a complex settlement space structure is formed: one is built according to the temple, close to the flat area of rivers and provincial roads; the second is built on the mountain, distributed on the gentle slope of the mountain.
4.2.3 The evolution of social security space form
In terms of livelihood model, social structure, and value cognition, in the traditional stage, all the means of production in Kejia Village were occupied by local governments, temples, and aristocratic heads, forming a serfdom economic system with regional characteristics (
Gug, 2014). At the beginning of the 17th century, the local government set up the Tangga market in the west of Kejia Village to support cross-border trade. The residents of Kejia Village took farming and animal husbandry + border trade as the basic livelihood mode of most families. Kejia Village is regarded as a necessary place for pilgrimage and a commercial hub for salt and grain trade. Until 1959, there were 82 households and 500 people in Kejia Village, and the residents showed a class hierarchy: 61% of the residents were Chaiba and 30% were Zhongqiong.
In the transitional stage, after 1959, Kejia Village carried out the reform movement of means of production, and all the villagers in Kejia Village took agriculture and animal husbandry as the main way of living. At the same time, it continued the border trade based on grain and salt and began to spawn an individual economy including individual blacksmiths, carpenters, sewing and cooked leather farmers. During this period, the formation of a “farming and animal husbandry + border trade + individual economy” business model, while continuing the settlement value of cultural hubs and border trade centers.
In the modern stage, since 2000, Pulan County, where Kejia Village is located, has been included in the key area of Xizang's border trade. The population of Kejia Village is 610. By 2020, the number of people engaged in agricultural and animal husbandry production in Kejia Village accounts for 28% of the total population, and 22% are engaged in non-agricultural and animal husbandry. After 2020, three cooperatives (Women's Cooperative, Perfume Factory, Construction Team) have been established in Kejia Village. The way of living in Kejia Village is mainly based on agriculture and animal husbandry, and at the same time, more diversified sources of income are derived, while the collective economy with family as a small unit and the village as a large unit still plays an important role. At the same time, it continues the settlement value of the cultural hub.
4.3 Spatial gene identification extraction and map construction of human settlement unit of Kejia Village
4.3.1 Spatial gene recognition and extraction
Based on the historical evolution process of the spatial form of human settlements, and the idea of spatial gene identification and extraction and map construction mentioned above, the spatial gene elements are identified and extracted from five aspects: landscape pattern, human pattern, settlement structure, road network structure, and architectural space.
4.3.1.1 Landscape pattern
The landscape pattern genome contains two sub-genes: natural order structure and distribution of farming space. The characteristic indicators include natural order structure and spatial distribution of farming space. Among them, the natural order structure refers to the combination sequence formed by mountains, water, fields, houses, temples, and canals. The spatial distribution of farming space reflects the utilization characteristics of ecological space by settlements. The main ecological utilization elements of Kejia Village are farmland and rivers, which are important resources for the survival of Kejia Village based on agriculture and animal husbandry. It can be seen from Fig. 9 that the sequence relationship between Kejia Village and mountains, water, and fields is significant: in the traditional stage, the flat land on both sides of the valley is used as a small area of farmland for farming, and ordinary residents live along the grottoes on the hillside. In the transitional stage, the farming space changed from the back mountain farmland to the gentle slope farmland at the foot of the mountain. In the modern stage, after the diversion of the Peacock River, the area of cultivated land was further expanded and migrated to the east bank of the Peacock River as residents moved (Fig. 9).
4.3.1.2 Humanistic pattern
The human pattern genome can show the internal spatial correlation characteristics of the settlement to a certain extent. This study uses space syntax to analyze the spatial topology of Kejia Village. Human pattern genes include two sub-genes: local association and spatial core, and their characteristic factor indicators include comprehensibility and topological core. In the modern stage and transition, the comprehensibility of settlement space is high (C = 0.9, C = 0.7), and the overall and local connections are close. The internal space organization is relatively regular, and the road network has strong integrity; in the transition stage, due to the large fluctuation of the terrain, the irregular road network, and the discontinuous space, the overall identification degree is not high, the connection of each part is small, and the intelligibility is 0.2. The spatial core of the settlement is small, but the core characteristics continue to be obvious. As a spatial carrier of residents' spiritual needs, Kejia Monastery has always been the core of the generation and development of village spatial structure, while Zan Temple is generated by secular needs, and its spatial binding force is relatively weakened with the evolution of the living mode in the process of village development (Fig. 9).
4.3.1.3 Settlement structure
The settlement morphology genome is an important factor to measure the specific spatial form of settlements at the meso level. The settlement structure gene covers two sub-genes of settlement shape and boundary shape, and the characteristic indexes include morphological index and fractal dimension value. The settlement pattern gradually evolved from a discrete shape to a strip shape, and then to a lump shape. The boundary form of the settlement is also from the traditional stage. The settlement building is on the ground with the mountain, and at the same time, it is close to the mountain and near the water to use the open valley to meet the needs of agriculture and animal husbandry, and presents a scattered distribution. In the transitional stage, the building gradually aggregates and presents a common boundary form. In the modern stage, on the basis of continuing the spatial structure of the existing settlements, the site selection of the new residential buildings has turned to the vicinity of the provincial roads with convenient transportation, and the complex boundary form is presented (Fig. 9).
4.3.1.4 Road network structure
The road network structure genome can reflect the road network composition and combination rules. Among them, the two sub-genes of road network ring and road network form are the internal characteristics of the overall road form order of the settlement. The characteristic factor indicators include the road network ring degree and the number of road network links, the connection value, and the number of external nodes. The overall road network connectivity of the settlement is gradually increasing. In the traditional stage, the degree of the road network forming a loop is low, and the main body of the road network is annular. The transition stage evolved into a medium-low ring road network, and its road network structure was dendritic; in the modern stage, the settlement road network evolved into a higher ring road network, and the road network form was composite. The connection value is low and inward is the main feature of the settlement connection form of Kejia Village in the traditional stage and the transitional stage, and the connection value is less than 25. Due to the scattered distribution of settlements and the limitation of water systems and terrain, it is easy to form an introverted road network with low density. The sparse population also leads to less connection between the main external roads and the entrances and exits of settlements (Fig. 9).
4.3.1.5 Architectural space
The architectural space genome contains two genetic projects of spatial functional composition and structural form, reflecting the construction experience in response to natural geography, climate, and regional culture. The characteristic factor indexes include functional composition, spatial order, spatial orientation, combined application of materials, and structural system. Figure 10 shows that most of the points in Ali Kejia Village fall on the left side of the comfort zone, that is, the air temperature is below the comfort temperature for most of the time, which means that the area is a cold area with an average annual temperature of 3.2 °C. The proportion of time required for humidification is only 1.0%, and the annual precipitation is less than 200 mm (Fig. 10). And the sunshine is sufficient, the average annual sunshine hours is 3219.2 h. It is windy all year round. The average annual wind speed is greater than 3 m/s, and the number of days with winds greater than eight in one year reaches 155 days (
Ding and Sai, 2017). Based on the above climatic conditions, a series of ecological construction experiences is used to deal with the unique climatic environment, which is embodied in the following aspects.
In terms of the functional composition of architectural space, including kitchens, bedrooms, Buddhist halls, storage rooms, etc., in the evolution of the living mode of “primitive mixed residence-summer and winter separation-functional composite”, there is always a dual-core of spiritual attributes and secular attributes. Among them, as the spiritual core of the living space, the mosque meets the needs of the residents' religious rituals. Because of the existence of a heat source, the room is warmer than other functional rooms, so it also becomes the core space for family members to meet the needs of cooking, heating, living, and other behaviors. Its manifestation is from the mud stove in the cave dwellings and the civil structure dwellings to the fire pond in the stone structure dwellings, until the living room with the stove as the center in the concrete structure dwellings, but it has always been the functional center of the residential space.
In terms of spatial orientation, the architectural space of Kejia Village is based on the mountain and takes advantage of the best orientation to avoid the wind and get sunshine. However, most of them do not adopt the north-south direction, but combine the dominant wind direction, religious beliefs, topography, and other factors to face the southeast.
In terms of spatial layout, the residential buildings are regular in shape, mostly square, and also have a square shape, and a small amount of “L” shape, etc., continuously showing an enclosed layout, which is conducive to reducing the windward area of the periphery of the building and avoiding the invasion of cold wind and dust. The layer height is generally lower (about 2.2 m), which is conducive to warmth. The internal space layout is compact to control heat loss. Through the winter and summer layered dislocation uses vertical space: the winter living room is located at the bottom of the building, and the area of contact with the outdoor enclosure structure is less, reducing the indoor heat loss, and close to the kitchen or merge with it, have a better indoor thermal environment. The summer bedroom is located on the top floor of the building. Compared with the bedroom on the first floor, the ventilation is smoother and the light is more sufficient. In addition, there are many small rooms without columns on the north side of the residential buildings, which are mostly used as storage rooms. Only small windows are opened for ventilation, which becomes a natural cold storage. At the same time, it can weaken the influence of winter cold current on the main rooms and play the role of a “climate buffer zone”. There are both horizontal and vertical conceptual axes.
In the horizontal direction, the “secular-sacred” dual spatial order is divided with the gang room as the axis: the shady side of the house is mainly used for secular life, placing food, fuel, sundries, and other spaces and toilets; on the sunny side is mainly sacred space, set up by the church, the Buddha Hall and neat room. In the vertical direction, the multistory residential buildings follow the Tibetan traditional space philosophy, and the spatial status increases with height: the bottom floor is used as a warehouse and a livestock ring, the second floor is used as a living area and a temple, and there are three floors.
In terms of the combination and application of materials, the natural resources in the Ali area where the village is located are scarce, the wood is relatively short, but the earth and rock resources are rich. Therefore, in the traditional and transitional stages, residents use raw soil and rubble as the main building materials. A small amount of wood is produced in Poland and Zhada, and most of them are exchanged from Nepal, Ladakh, and other places through barter exchange, forming two basic types of raw soil architecture and civil architecture. In terms of structural systems, in the traditional and transitional stages, the column, main beam, and secondary beam are all about 2 m. This is due to the fact that traditional transportation relies on manpower and livestock, so it is necessary to cut wood (TBSDI, 2011). In addition, because the conduction heat loss of the external envelope structure dominates the total heat loss of the building (
Shou et al., 2018), the external walls of the residential buildings are mostly adobe walls, which are made of adobe bricks and a small amount of straw, and a small amount of pebbles is mixed in the clay as aggregates. The thermal conductivity of adobe bricks is stronger than that of some commonly used wall blocks, but such walls are thick and heavy, and the thermal resistance is higher, which is conducive to thermal insulation. In the modern stage, the reinforced concrete structure is tried (Fig. 11).
4.4 Classification of spatial genes of Kejia Village
Based on the synchronic evolution analysis of the spatial form of human settlements in Kejia Village, its evolution shows both stability and development characteristics. Among them, the stability feature refers to the formation of a relatively stable and local consensus spatial combination model in the evolution of human settlement units. Variable characteristics are the opposite. Based on the spatial genes identified and extracted above, by comparing the spatial gene characterization and connotation of the three stages of the development of Kejia Village, the spatial genes are divided into two types: stable genes and variable genes.
4.4.1 Stability gene
The stable spatial gene involves three spatial genomes: landscape pattern, humanistic pattern, and architectural space, which are embodied in four spatial genes: natural order structure, local correlation and spatial core, and spatial composition, and are respectively manifested as: double core, mountain orientation, and order. First, the spatial organization of human settlement units continues to show the characteristics of the mountain, and the road system presents an organic form. The deep connotation of this spatial gene lies in the continuation of the mode of production based on agriculture and animal husbandry. As early as the Tubo period, the valley agriculture dominated by the lowlands of the Peacock River Valley had taken shape and formed a serfdom economic system with regional characteristics. The Kejia villagers living in the Peacock River Valley call themselves “Xinba”, referring to the group of “Valley agriculture and nomadic culture typical” with the background of valley settlement agriculture. After 1959, the way of villagers' access to resources and the way of production and operation changed. However, due to the relatively long distance from the central city of Xizang, the cost and risk of labor transfer are high, which does not conform to the local development law. Therefore, under the consideration of opportunity cost, no one in Kejia Village goes out to work but establishes a collective economy to provide jobs for the whole village. Agriculture and animal husbandry are still the most important way of living. The appellation of “Xinba” is still the symbol of the identity community of Kejia Village.
Secondly, the dual-core of spiritual attributes and secular attributes always exists in the settlement and architectural space of Kejia Village. The connotation of this spatial gene lies in the belief of local gods. In the Ali area, in addition to Tibetan Buddhism, each village also has its own local gods to bless the village. The space people radiated by the local gods should have the same value cognition, abide by a set of religious taboos together, and form a settlement community. As a typical traditional village in the Ali area, the local god of Kejia Village is the praise god to bless the village with a good harvest. Every year on the tenth day of February in the Tibetan calendar, the whole village burned incense to the Zan temple to predict the harvest and disaster of the year. Even though the spatial connection between the temple and the village has gradually weakened, the general belief based on the Kejia Monastery and the ideology represented by the local gods still plays an important role in the settlement community of the Kejia Village.
Thirdly, the layout of Tibetan residential buildings reflects the spatial order of traditional Tibetan culture. There are conceptual axes in both horizontal and vertical directions in Kejia villagers' houses. The connotation of this spatial gene is that the family is the most basic unit of the settlement in Kejia Village. In the traditional stage, the number and area of holes in cave dwellings are generally based on the family population. After the democratic reform, a family economic structure was formed, which organically combined agriculture and animal husbandry, the family handicraft industry, and the planting industry. The family income was proportional to the labor force, which stimulated the desire of farmers and herdsmen to expand the family size. After solving the problem of basic food and clothing, the main investment of the family gradually shifted to improving the housing, which promoted the construction of new houses in Kejia Village. By 2024, the concept of unified living is still the mainstream in Kejia Village: 39% of nuclear families, 39% of backbone families, 8% of backbone families plus siblings, 4% of nuclear families plus siblings, and 10% of special families. It can be seen that in the social organization, livelihood structure, and value cognition of Kejia Village, the traditional living concept and spatial order with family as the unit have been continued.
The settlement and residential space form a coupling relationship between the spatial organization of the living unit and the alpine climate through the dual-core, the mountain, and the axis division, and divide the God's space, human space and natural space at the spatial representation level. At the same time, relying on its connotation, the three types of space are integrated into a living unit that guarantees ecological, human, and cultural security. The spatial system not only presents the wisdom of mutual fitting between nature and humanity, sacred and secular but also forms a community of dual dimensions of space and identity.
4.4.2 Variable space genes
The variable genes of spatial form are mainly reflected in the four genomes of landscape pattern, settlement structure, road network structure, and architectural space, which are embodied in the spatial genes of the spatial distribution of cultivation, settlement form, boundary form, road network ring, road network form, and structural form. In terms of the spatial distribution of farming, it has undergone a process from scattered small-area farming to intensive mechanical planting. In terms of settlement and boundary form, it has undergone a process of spatial form change from discrete to strip and then to composite. In terms of road network form, the settlement connection in the traditional stage is mainly based on the narrow mountain road, and the branch of the mountain road leads to each cave. The main body of the road network form is circular. In the transitional stage, the road space form presents a dendritic shape with the formation of the new residential group, and at the same time connects the spiritual property of the holy monastery of Kejia and the secular property of the holy temple of Zan. The modern stage is complex.
In terms of building materials and structural systems, the cave dwellings are formed by digging holes in the earth's mountain, with a height of about 1.7–2.0 m. Indoor traffic is connected by aisle or underpass, with only doorways and ventilation and lighting outlets; with the gradual convenience of transportation, wood transportation has been improved, and residential buildings are generally a combination of earth-built walls and wooden beam frames. The civil structure houses are supported by beams, columns, and rafters, which are surrounded by rammed earth walls. The height of the layer is about 1.8–2.5 m, and the basic column network system of 2.0 m is formed. At the same time, the semi-circular single-wood ladder is used as the traffic space connecting the upper and lower layers; the stone-wood structure residential building is about 2.0 m high, which continues the semi-circular single-wood ladder, and sets up a solar room to strive for sunshine heating; the structural elements of new reinforced concrete dwellings change with the emergence of new materials. Such as the use of concrete blocks instead of rammed earth walls, asphalt felt membrane instead of traditional roof waterproofing, colored steel tile instead of a traditional roof, etc. Therefore, its floor height has also increased to 2.8 m, and the solar room has expanded from the past 1.2 × 1.2 m2 to 5.4 × 3.6 m2, and the single-wood ladder has evolved into a single-run staircase.
Therefore, it can be seen that the order of spatial gene changes in the living unit of Kejia Village is always in direct proportion to its symbolic significance: the more symbolic and sacred the place is, the more tradition is maintained, such as temples, chapels, Buddhist halls, shrines, divine seats, etc. The weaker the symbolic meaning and sacredness, the more practical the place is the first to change. For example, the farming space and road network structure conform to the production and living needs of the settlement, and the architectural space is also the most receptive to modern structural systems and materials.
4.5 Construction of spatial gene map of human settlements unit of Kejia Village
Based on the five genomes and their type characteristics of landscape pattern, human pattern, settlement structure, road network structure, and architectural space, the internal genes are encoded regularly and uniformly in a way similar to the human gene map. Each gene has 2 to 4 different expression forms, which are expressed in different colors of the same color system. The corresponding relationship between the color block and the gene is formed, and then the spatial gene map of the human settlement unit in Kejia Village is formed.
The human settlement unit of Kejia Village is based on the stable genes in the five spatial genomes, and realizes dynamic adaptation through the variable genes, so that the spatial organization and the alpine climate form a coupling relationship, and reflect the traditional Tibetan cultural and spatial views, which reflects the internal logic of ecology, human settlement and cultural interaction. The stratification process of its spatial gene pedigree has three characteristics: the dynamic adaptation of human settlements and ecological environment, the interactive evolution of spiritual space and secular space, and the integration of traditional and modern development. First of all, the dynamic adaptation characteristics of human settlements and ecological environment refer to the gradual shift of human settlements from natural attachment to technical intervention, such as the setting of winter and summer rooms, the continuation of solar rooms, and the application of modern building materials to balance the needs of alpine environment and comfort. Secondly, the interactive evolution of spiritual space and secular space means that the spiritual space (monasteries, temples, shrines, and rooms) of the living unit remains stable, while the secular space (roads, houses) is dynamically adjusted with demand. Furthermore, the characteristics of the integration of traditional and modern development, that is, the symbolic space (Buddhist halls, mosques) adheres to the tradition, and the spatial distribution of farming, settlement form, road network form, and the structural form of the building give priority to modern technology (Fig. 12).
4.6 The inheritance mechanism of spatial gene map of human settlements unit of Kejia Village
Based on the stratification context of the spatial gene map of the human settlement unit in Kejia Village, constructs a deconstruction framework of the stratification object of the spatial gene map from stratification to accumulation (Fig. 13), summarizes the historical stratification relationship model of the spatial gene, and analyzes the ecological, human settlement and social factors that affect the spatial gene change under different stratification conditions, thus revealing the spatial gene stratification mechanism of the human settlement unit in Kejia Village.
4.6.1 Layering model of spatial gene of human settlement unit of Kejia Village
The evolution of the spatial gene of the human settlement unit in Kejia Village shows obvious stratification characteristics: in the traditional stage, it is dominated by religious beliefs and natural adaptability, and the residents spontaneously stay in the caves to form a discrete settlement space structure with spiritual core and natural attachment characteristics. Its spatial gene inheritance presents a bottom-up one-way feature.
In the transitional stage, under the leadership of the state, the ownership reform of the means of production provides an institutional basis for the accumulation of wealth of farmers and herdsmen. Farmers and herdsmen gradually moved closer to temples and water systems through the construction of independent dwellings to protect cultivated land. The spatial structure of the settlement turns to the banded coexistence of spirit and secular core. The evolution of spatial genes presents the characteristics of top-down and bottom-up two-way intervention.
In the modern stage, driven by economic diversification and transportation convenience, under the overall adaptation system of agriculture and animal husbandry, villagers can engage in business through collective or individual economic forms. The dwellings are transformed into “secular dominance + technological innovation”, but still retain the core spiritual attributes. The spatial structure of the settlement is also based on the continuation of the spiritual core, gradually forming a composite feature, and its spatial gene evolution presents multi-level symbiotic characteristics.
The above-mentioned spatial gene stratification process of Kejia Village shows the following logic: the spatial gene of each stage does not completely replace the previous stage, but superimposes new adaptive genes on the basis of retaining the core stability gene to form a composite structure with both stability and adaptability.
4.6.2 Influencing factors of spatial gene map accumulation of Kejia Village
The stratification process of the spatial gene of the human settlements unit in Kejia Village reflects a grand social background. The following discusses its influencing factors from three aspects: ecology, society, and human settlements.
The influencing factors of ecology are embodied in three aspects: severe cold climate, geographical conditions, and resource constraints. Among them, the severe cold climate promotes the continuation of heating space (mud stove, fire pond, and stove), and also drives the evolution of residential building functional zoning (winter and summer bedrooms), as well as the introduction of solar rooms; according to the geographical conditions, the location of the settlement is gradually shifted from the location near the mountain to the convenient transportation, reflecting the adaptive adjustment of the human settlement unit to the protection of cultivated land and the acquisition of resources. Under the limitation of resources, the difficulty of timber transportation leads to the limitation of the height and column network of traditional buildings, and the introduction of modern materials (concrete, color steel tiles) breaks through the ecological constraints.
The social influence factors are reflected in three aspects: policy influence, religious belief, and cultural identity. In terms of policy impact, after the economic system reform in 1978, the household contract responsibility system enabled farmers and herdsmen to have the autonomy of production and operation linked to their respective interests, thus continuing the family economy. After the reform and opening up, Pulan County was included in the key area of the development strategy of Xizang's border trade towns. Kejia Village was positioned as the central village and characteristic protection village on the axis of urban and rural development. The rich local employment opportunities avoided the outflow of the labor force. In addition, the Chinese government has also implemented a series of projects and policies on contemporary settlement planning in the border areas. At the end of 1995, seven towns in the Ali area, such as Pulan, Zada, Ritu, and Gaer, were approved to carry out urban planning, which opened the orderly construction of border settlements. After 2000, the infrastructure and business environment of Kejia Village have been greatly improved, and more employment opportunities have been created after the implementation of the farmers' and herdsmen's housing project focusing on rural housing renovation, nomadic settlement, and poverty alleviation and relocation. With Kejia Monastery as the center, almost all the houses built on the street and along the highway have opened shops (the construction area of Kejia Village is 20438 m
2) (
LCCCT, 2011). In 2019, there were 6 restaurants opened by local people in Kejia Village and 1 outsider. There are 6 hotels and 8 commissaries (including 6 catering and small commodity sales), which further broadens the way of income of villagers in Kejia Village. After 2010, the Chinese government introduced a border subsidy policy. The policy stipulates that each person is given a subsidy of 4200 CNY per year (excluding people under the age of 16). If the border residents do not live on the border for more than half a year, the border subsidy will be canceled. This policy has strengthened the willingness of farmers and herdsmen to stay in Kejia Village. Furthermore, based on the profound historical and cultural characteristics of Kejia Village, the costumes of Kejia Village were included in the national intangible cultural heritage list in 2008, and Kejia Village was selected as the seventh batch of Chinese historical and cultural villages in 2019. Then, in the “Pulan County Land and Space Master Plan (2021–2035)”, Kejia Village was positioned as the central village on the axis of urban and rural development on the Ali border and was also included in the characteristic protection villages. With the promulgation of relevant cultural protection policies, the protection of Kejia Village has been incorporated into the country's traditional village protection system, which provides a guarantee for the inheritance of its living units. In terms of religious beliefs, the dual-core has always dominated the settlement and architectural space form to varying degrees. In terms of cultural identity, the horizontal and vertical axes continue the traditional spatial order, and the local god belief maintains the identity of the settlement community.
The elements of human settlements are reflected in four aspects: family structure, livelihood model, technological innovation, and population migration. In terms of family structure, the family has always been the basic unit of the living mode, and the intergenerational inheritance of the family economic structure has continued the traditional living concept. In terms of subsistence mode, in the process from the dominance of agriculture and animal husbandry to the coexistence of diversified subsistence, the dominant position of agriculture and animal husbandry has been maintained, and the settlement has been promoted to expand to traffic nodes. In terms of technological innovation, the updating and iteration of the spatial scale and auxiliary space of the building structure reflects the progressive improvement of practicality priority.
In terms of population migration, in 1630, Ladakh conquered the Pulan area by force for more than 50 years, and the area where Kejia Village was located became a way for the residents of surrounding countries and regions to migrate. In addition, as a regional religious center, Kejia Monastery attracts believers from Nepal, India, and other regions to pilgrimage and further promotes the flow of people. In addition, in history, the border residents of China and Nepal have always had the habit of cross-border grazing. From the 17th century to 1959, there were two pastures (Yongba and Lalai) in Kejia Village in Nepal for the residents of Kejia Village to migrate and graze in summer. After 1959, China and Nepal reached three agreements on cross-border grazing. During this period, Nepalese border residents also arrived in Kejia Village and Pulan county to engage in seasonal work and form temporary residential areas. However, due to the border policy, a permanent settlement community has not yet been formed. This flow is not only a microcosm of the economic interaction between Xizang and Nepalese border settlements, but also a reflection of the unique pattern of population migration in the Himalayan region.
4.6.3 Inheritance mechanism of spatial gene map of human settlement unit of Kejia Village
The inheritance mechanism of the spatial gene of Kejia Village can be summarized into the following four aspects: First, the living unit has always continued the tradition of the coexistence of spiritual and secular cores and has always reflected the clear division of “God's space,” “human space,” and “natural space,” and is closely related to the spatial order. Secondly, the elements and forms of symbolic space are preserved and continue to meet the inheritance of regional context. The shape, structure, and materials of the practical space will be replaced by new technologies and materials in order to balance the needs of the alpine climate and residential comfort. Third, under the traditional family-based living mode, it continues to adapt to the development of ecological changes and subsistence patterns through new residential construction and spatial organization. At the same time, relying on Tibetan Buddhism and local God belief, the settlement ideology can be maintained, and the regional cultural identity can be formed to buffer the impact of modernization and inhibit the fracture of spatial genes. Fourth, the development of human settlements units has gradually shifted from natural dependence to technical intervention, and then to coordinated adaptation. Through the composite superposition of spatial genes in each stratification stage, a dynamic balance of coordinated evolution of ecology, human settlements, and society is formed.
5 Conclusion and discussion
5.1 Conclusion
This study combines human settlement science with spatial gene theory and its technical methods, introduces the research field of human settlements in border settlements, and constructs the identification, extraction, and analysis methods of construction experience in the historical space of border settlements. The following conclusions are obtained.
Firstly, 10 genes and their characteristic indexes of 5 genetic groups of the habitat unit in Kejia Village were identified, extracted, and condensed, and quantitative and qualitative descriptions were made. According to the classification of gene characteristics, the map of the human settlement unit in Kejia Village was summarized and drawn. The spatial gene of the human settlement unit in Kejia Village is embodied in five aspects: landscape pattern, cultural pattern, settlement structure, road network structure, and architectural space. Among them, the stability genes (natural order structure, spatial core, and spatial composition) and the variability genes (road network morphology and structural morphology) coexist. As the cultural foundation, the stability gene ensures the settlement identity and function continuation. Through technological iteration and functional optimization, the variable genes achieve a dynamic balance with the external environment, thus shaping a unique living unit with both cultural continuity and functional adaptability.
Secondly, the stacking of spatial genes in Kejia Village has transformed from one-way dominance to two-way intervention, and then to multi-level symbiosis. Under the combined influence of ecology, society, and human settlements, new genes do not negate old genes but superimpose and coexist, forming a spatial gene pedigree with certain stability and adaptability. The inheritance mechanism of its spatial gene is reflected in four aspects: the dynamic adaptation of human settlements and ecological environment, the stable inheritance of humanistic spatial structure and architectural spatial order, the gradual evolution of settlement spatial form, the renewal and iteration of architectural structure and materials, and the deep maintenance of settlement social structure.
Furthermore, with the development of Kejia Village, through the inheritance of the wisdom of human settlement unit construction, a community of human settlement units in Xizang border settlements based on language, blood, cognition, and belief has been formed. Compared with the high-tech construction technology, the suitability construction method is more suitable for the construction of the typical border settlement living unit of Kejia Village, which is based on the objective conditions of low labor transfer rate, low technical level, and weak economic foundation. The key to its suitability construction method is not the protection or reproduction of historical forms and symbols themselves, but the continuation of the regional combination mode of spatial elements and its internal generation mechanism. Therefore, it is necessary to continue the existing stable space genes and moderately iterate the variable genes to realize the security construction, ecological construction, and green human settlement construction of Xizang border settlements. At the same time, we should also fully respect the local social tradition, respect the wishes of the local people, and respect the autonomy of the local people to create technological development.
5.2 Discussion
These conclusions provide theoretical and practical references for research on identifying and understanding the development mechanisms of construction wisdom in Xizang's border settlements, which are characterized by small populations, small scale, and sparse distribution. It provides guidance for the protection and inheritance of settlements with regional characteristics and plays an important role in promoting the inheritance and development of local civilization space in border areas.
At the same time, it should be pointed out that there are some limitations in this study. First of all, due to the geographical particularity of the research object, the scarcity of historical patterns, the lack of historical materials, and language differences, there are some limitations in the realization of the whole sample survey and the interpretation of historical texts. Admittedly, for the above reasons, this paper fails to explore the specific application of methodology in a wider range of spatial case studies. Therefore, in the follow-up study, we can identify and extract the spatial genes of the Xizang border settlement living units in the transformation of spatial scales according to the needs, and form a more complex border settlement living unit to create a smart pedigree. Therefore, it is urgent to further explore and construct the index system of the identification, extraction, and evaluation of the wisdom of the construction of the living unit of the border settlement in Xizang, to expand the adaptation boundary of the research paradigm, to play a guiding role in the construction of the border settlement in a broader regional scope.
2095-2635/2025 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.
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