Habitat-site Design and Practice of the Built Environment
刘 晖 王晶懋 许博文
LIU Hui, WANG Jingmao, XU Bowen
刘晖 / 1968 年生 / 女 / 辽宁人 / 博士 / 西安建筑科技大学建筑学院教授、博士生导师 / 研究方向为西北脆弱生态环境景观规划设计理论与方法、中国地景文化历史与理论
通信作者邮箱 (Corresponding author Email): firstname.lastname@example.org
LIU Hui, female, who was born in 1968 in Liaoning Province, is a professor and doctoral supervisor of College of Architecture, Xi’an University of Architecture and Technology, the editorial members of this journal. Her research focuses on landscape planning and design theory on the green space in northwestern cities in fragile ecological region of China, Chinese landscape culture history and theory.
王晶懋 / 1988 年生 / 女 / 内蒙古人 / 博士 / 西安建筑科技大学建筑学院副教授 / 研究方向为西北脆弱生态环境景观规划设计理论与方法
WANG Jingmao, female, who was born in 1988 in Inner Mongolia, is the associate professor and works in College of Architecture, Xi’an University of Architecture and Technology as a post-doctoral. Her research focuses on landscape planning and design theory on the green space in northwestern cities in fragile ecological region of China.
许博文 / 1994 年生 / 男 / 陕西人 / 西安建筑科技大学建筑学院在读硕士研究生 / 研究方向为风景园林规划设计
XU Bowen, male, who was born in 1994 in Shaanxi Province, is the master candidate in school of architecture, Xi'an University of Architecture and Technology. His research focuses on the planning and design of landscape architecture.
Abstract: The urbanization development of northwest China is restricted by fragile natural ecological environment, in this way a new ecological process under artificial intervention is necessary. Taking Manual Intervened Ground-cover Plant Community Composition (MIGPCC-BE) and Spontaneous Ground-cover Plant Community Composition (SGPCC-BE) as the research objects, we built a number of one-squaremeter habitat-site units. These small-scale green spaces provide opportunities to improve the plant community diversity. After the construction of the habitat-site garden, it not only undertakes the teaching task, but also affects people's behavior and activities, improving the surrounding residents’ awareness on plant ecological knowledge. Adopt appropriate design approach and apply the habitat-site design model to the built environment can promote the realization of the vision of "Beautiful China".
Key words: built environment; habitat-site design; habitat-site garden; groundcover plant community composition
1 1 m2 的潜力：城市中的生态美
群落生态学的研究表明，1 m×1 m 的生境内可包含一个完整的草本群落生态系统，作为植物群落组构及设计的基本单元，适用于建成环境独立而破碎的绿化场地。研究发现，以“自然参与”为途径的设计研究与实践存在六种植物群落种植模式，本文选择适宜中国建设模式的两种作为研究对象，即“人工地被植物群落组构”和“自生地被植物群落组构”（图2）。按照群落组成的分层理论、植物群落竞争理论（CRS）、季相感官特征等，选择乡土植物，构建四个实验群落，组成八种实验样方（图3）。
图1 西北半干旱地区附属绿地中的1m×1m 实验样方
Figure 1 1 m×1 m Experimental Quadrates in the Appendage Green Land in Northwest China Semi-arid Region
图2 “ 人工地被植物群落组构”和“自生地被植物群落组构”植物群落种植模式比较
Figure 2 Comparison of“Manual Intervened Groundcover Plant Community Composition (MIGPCC-BE)” and“Spontaneous Ground-cover Plant Community Composition (SGPCC-BE)” Plant Community Planting Patterns
图3 “ 自生地被植物群落组构”实验群落与样方
Figure 3“Spontaneous Ground-cover Plant Community Composition (SGPCC-BE)” Experimental Plant Community and Experimental Quadrates
在扬 • 盖尔的《交往与空间》一书中，把公共空间中的活动类型分为必要性活动、自发性活动和社会性活动三种，根据活动发生的频率，又可以将其分为高频行为、中频行为与偶发性行为。通过观察和分析西安建筑科技大学南门花园的录像，按照该分类方式对人的行为进行解析与归类。
同时，花园也提高了周边居民对植物生态知识的公众认知度。自2016年开始，相关部门便开展了公众对植物群落景观偏好的研究，进而对生境花园中群落的设计方法进行优化。研究内容包括植物群落生物多样性可感知程度、植物群落环境的影响程度、标示牌对提高公众认知度的影响等内容。有85 %的居民是被植物吸引而来，有77 %的居民想学习植物和生态学的知识。另外，居民也会主动表达自己对花园的想法，并询问花园的设计与管理，从多角度理解风景园林学科（图5）。
Figure 4 Seasonal Characteristics Changes of Two Plant Communities in South Gate Garden
第二，地被植物群落作为城市建成环境生态格局中生境斑块，如何介入？基于1 m2×1 m2植物群落人工组构的基础样方，提出“生境岛”，以其适宜的形态置入到绿地、硬质铺地中，通过进一步空间格局构建，构成有价值的生境网络（图7）。
Figure 5 Teaching Activities and Public Participation in the South Gate Garden
Figure 6 Public Participation and Recreation in the South Gate Garden
Figure 7 Habitat-site Continuity Design Pattern
Ecosystems exist in multi-scale environments. Small-scale space environment also contains rich ecosystems, which are composed of biological communities and habitat-sites. Biological communities include plant communities and animal communities, and habitat-sites are jointly affected by climate environment and soil environment. It is obviously that ecosystem exists in both natural environment and urban built environment . As the world enters the "urban century", cities have not only meant the simple way of living in modern times, but also have great significance to the development of human society . Urbanization has brought about a new ecological process, which is closely coupled with the spatial pattern of urban green space constructed by artificial facilities such as buildings and roads. In the past 20 years, China is experiencing unprecedented urbanization. The original oasis ecosystem has been replaced by cities under large-scale construction . How can we take necessary human intervention measures in the construction of urban green space and rely on urban construction to build artificial oases so as to realize a new ecological process accompanying the development of urbanization? Strengthening the ecological service function of various green plant communities in the city may be the only way for the healthy and sustainable development of the city.
The quality of green space planning and construction in cities is not only an important content of "Beautiful China" in the construction of healthy and beautiful living environment, but also a practical field serving national strategies such as ecological garden city, urban double restoration, sponge city, garden city, etc. The characteristics of urban greening construction in China are reflected in many aspects, such as large scale, high public demands, government attention, and diverse natural conditions of the land. There are also problems such as single construction mode. According to the characteristics of urban greening construction, the theoretical and methodological research on environmental habitat-site design has been carried out, which is based on the following background. First, the habitat-site conditions in the built environment of a city are different from the natural habitat-site conditions, and its ecosystem has particularity . In modern urbanization development in China, it will be worthwhile to study how to build a good urban ecosystem. Second, the habitat-site prototype in northwest China is mainly composed of ground-cover plant communities. Ground-cover plant communities can grow rapidly on small-scale sites, and this habitat-site prototype has uniqueness and suitability in urban construction . Third, there are many types of greenbelts in the built environment of cities, which have ecological significance and gradually form unique ecological systems. It is coupled with the fragmented small-scale green space in the built environment of the city, and plays an ecological benefit of a small-scale site. Therefore, it is significant to study the ground-cover plant community on the site scale.
1 Potential of One Square Meter: Ecological Beauty in Cities
Habitat-site in the built environment of the city consists of building structure, paving and other artificial facilities. Its habitat-site factors include urban microclimate, urban hydrology and soil conditions, etc. Compared with its natural environment, the habitat-sites in cities of arid and semi-arid regions are richer in diversity and have certain characteristics of typology and similarity. The plant community and succession under its influence also have similar laws.
According to the investigation of the spontaneous ground-cover plant communities in the typical habitat-site of Xi 'an, Lanzhou, Yinchuan, Xining and Urumqi in northwest China arid and semi-arid regions, it can be found that there are 7 natural prototypes of grassland in the natural vegetation region: grass, sparse forest grass, mountain grassland, mountain meadow grassland, plain desert grassland, mountain desert grassland and mountain desert. According to the investigation of the spontaneous ground-cover plant communities in typical habitat-site of these cities, it can be found that their plant communities have similar community composition characteristics: the structure includes 2-3 layers, the species richness is 3-14/m2, and the coverage rate of dry land is relatively low (figure 1). The community species have small leaf area and fine texture. In summer, it is colorful and changeable. In autumn and winter, its color is mainly brown and yellow. In spring and summer, there are a small number of flowering plants as embellishments, and in winter, withered plants are the main ones.
Studies on community ecology show that a 1 m×1 m habitat-site can contain a complete herbaceous community ecosystem. As the basic unit of plant community structure and design, it can be applied to greening sites that are broken due to independent built environment. According to the research, there are 6 plant community planting patterns in the design research and practice through "natural participation". The research group has chosen two kinds of suitable construction models in China as the research objects, namely "manual intervened ground-cover plant community composition" and "spontaneous ground-cover plant community composition" (figure 2). According to the hierarchical theory of community composition, plant community competition theory (CRS) and seasonal sensory characteristics, native plants were selected, 4 experimental communities were constructed, and 8 experimental quadrates were composed (figure 3).
After nearly three years of experiments and observation, the feasibility and design pattern of the two ground-cover plant community structures in terms of ecological value and aesthetic feeling were found. The manual intervened groundcover plant community composition is suitable for the demand of landscape type and more artificial intervention. The key of this mode lies in the layered artificial intervention mode among structural layer, ground-cover layer and seasonal layer. Among them, artificial mulch can be used to keep soil moisture in the semi-dry and wet areas in the northwest when the local cover is not formed. The seasonal layer can enrich the landscape effect of plants, and the structural layer can maintain the sustainability of the landscape during the withering period (figure 4). The spontaneous ground-cover plant community has more characteristics of natural wilderness. Through manual intervention and phased intervention of plant species, the aesthetic perception of plant communities can be increased, which can make the ground-cover easily formed. However, the winter withering period of the spontaneous ground-cover plant community is relatively long, and artificial intervention can improve the aesthetic degree of the winter withering period. The improvement of spontaneous ground-cover plant community has more adaptability in the negative space of urban sparse forest meadow, river channel restoration, slope greening and urban built environment.
The two types of communities can once again show the color, texture, seasonal characteristics and perceived species diversity of the natural communities in the northwest arid region. The diversity and dynamics of community landscape bring rich and lasting natural experiences to people of different ages in the city. The "habitat+ plant community" unit of one square meter can become the "cell" of the urban ecosystem. They can split and spread in fragmented urban habitatsite. Community models suitable for different habitat-sites can make full use of diversified urban habitat-sites and create a pattern of urban biodiversity. More ecosystem services and social benefits can be brought by multi-scale and multilevel habitat network systems. Independent green space with site scale has many plates, wide distribution, fragmentation and other characteristics in the city. In the ecological construction of urban green space in northwest China, small-scale green space with artificial intervention provides an opportunity for the diversity of plant communities .
2 Urban Plant Communities and Humans: Social Preference and Public Education
2.1 Behavioral Activity Analysis
In "Communication and Space" of the author Jan Gell, the types of activities in public space can be divided into three types: necessary activities, spontaneous activities and social activities . According to the frequency of activity, it can be divided into high frequency behavior, intermediate frequency behavior and sporadic behavior . By observing and analyzing the video of the South Gate Garden of Xi 'an University of Architecture and Technology, human behaviors are analyzed and classified according to this classification.
Both necessary activities and social activities are strongly guided and involuntary. Therefore, in order to better analyze the spontaneous interaction between visitors and plants entering the site, we have classified the spontaneous activities in detail. We have further refined the types of activities according to whether they are related to plants and the frequency of occurrence of behaviors. The analysis results are shown in table 1.
2.2 Bearing a Certain Educational Significance
East building garden and south gate garden have a history of 15 years since they were built in 2003. They not only promote teachers and students of architectural engineering universities to have a new ecological cognition of landscape architecture design specialty, but also profoundly change and shape its builders, managers, participants and visitors. Moreover, they provide interesting venues and a new perspective of learning for nearby residents. The design and construction of gardens have accompanied the growth of landscape architecture discipline and witnessed the development of landscape architecture education in a university. The garden can be regarded as a condensed history.
The experiment of ground-cover plant habitat-site design in the south gate garden often attracts many teachers and students from home and abroad to observe and exchange. The completed garden provides a multi-objective teaching platform for teachers and students. Teachers and students not only design, build and maintain gardens, but also carry out site mapping, observe the evolution of plant communities and make natural notes. It provides a teaching place for professional teachers and students. During the festival, the elaborately decorated garden became the focus of the whole school. Garden has become a part of community life.
Meanwhile, the garden has also improved the public awareness of the surrounding residents on the knowledge of plant and ecology. Since 2016, the research on public landscape preference of plant communities has been carried out, and then the community design method in the habitat garden has been optimized. The study includes the perception of plant community biodiversity, the influence degree of plant community environment, the improvement of public awareness of billboard explanation education, etc. 85% of the residents who enter the garden are attracted by plants, and 77% believe they learn about plants and ecology after entering the garden. In addition, they will actively show their interest in the garden, ask about the profession of garden design and management, and understand the discipline of landscape architecture from various angles (figure 5).
2.3 Plant Landscape Affecting Behavior
Three cameras are installed in both garden sites to record the continuous shooting of the garden. In the 12 months from August 2017 to July 2018, six clear days in each month are selected as the video reading date. Three time periods of each day are selected for statistics. The autumn equinox is on September 23, 2017, and the spring equinox is on March 21, 2018. Therefore, between September 23, 2017 and March 21, 2018, the specific observation period includes 7: 00-9: 00, 11: 00-15: 00, 16: 00-18: 00. Outside this interval, the specific observation period includes 6: 00-8: 00, 11: 00-15: 00, 18: 00-20: 00. The video mainly reads the number of people entering the venue every day, the frequency of interaction between people and ground-cover plants, and the behavior of people in the venue.
In the video reading, we can find that the average daily traffic in February is the lowest, at this time the garden plants are weak and the garden scene is depressed. The number of tourists reached its peak in March, attracting an average of 86 a day. Because of the flowering of plants in spring and summer, the special texture of plants in autumn and the withered and unyielding form of plants in winter, the ground-cover plant community region under the habitat-site design mode is more attractive than the traditional planting region. As the garden is located on the campus of a university, young and middle-aged people account for more than 70% of the tourists who enter the venue every day. Young and middle-aged people mainly take walks, take photos and wait for someone in the venue. Children often enter the garden accompanied by adults. They are more curious about the environment, like to touch plants with their hands, walk through the paths in the venue, and are more willing to play and play in the cluttered places in the venue. The elderly prefer to lean over and observe the plants closely after entering the venue. They have strong curiosity about the identification system and experimental observation instruments in the garden and would like to communicate and inquire with students.
In addition, the areas where tourists stop for a long time are different in each month of the year. The plants in the region have no obvious regularity, but we can find that the growth characteristics of ground-cover plants in the region do have obvious regularity (table 2). Spring is the season when plants bloom in large quantities. Therefore, tourists stay longer in areas with more flowers. This has nothing to do with the flowering form and color of plants. Moreover, due to the small amount of plants, factors other than the plants themselves are more obvious, such as containers and soil covers. In summer, the flowering period of many plants has passed. Therefore, in addition to flowering, the texture and growth of plants have also become an important factor for tourists to stop at this stage. After entering autumn and winter, the growth of most plants began to weaken and gradually wither. Therefore, plants that still bloom will become the focus of the whole field in autumn and winter. In addition, evergreen plants and plants with withered and unbreakable branches will attract tourists to stop and watch for a long time when plants wither in a large area, which will bring important inspiration to our design in the future (figure 6).
3 Design Language and Practice: Habitat-site Design
Research on the construction of built environmental ecosystem exists in many disciplines and practice fields. The discipline field of design and construction has many challenges to the practical application of ecological knowledge. Facing the challenges of cross-disciplinary cooperation, Chinese and western cultural context, and the cultural background of the public landscape preference, Chinese landscape architecture discipline also has great demand in practical application. It is particularly important that appropriate design language is proposed. The process of habitat-site design and practice of the built environment is mainly reflected in the following aspects:
First, on the basis of general site design and construction methods, the basic procedures and contents of habitat-site design are proposed. In the first step, combining site analysis and functional zoning, the "site habitat type" is evaluated and analyzed, and the "site habitat zoning" is carried out. The second step, combining landscape element design and its spatial layout, "ground-cover plant community composition" type and shape design are carried out, and spatial layout is implemented according to ecological and aesthetic performance requirements. The third step, combining the project implementation requirements, the implementation plan of "ground-cover planting" was carried out. The last step is maintenance and management. In order to promote the succession of ground-cover plant communities to reach a relatively stable state, annual seasonal "continuous design" and "succession maintenance" are carried out.
Second, how does the ground-cover plant community intervene as a habitat-site patch in the urban built environmental ecological pattern? Based on the basic sample quadrate of artificial fabric of 1 m2×1 m2 plant community, we propose "Habitat-site Island". Its suitable form is applied to green land and hard floor. Valuable habitat-site networks are constructed through further spatial pattern construction (figure 7).
Third, the practical application opportunities brought by sponge city construction. In the construction of sponge city in Fengxi New Town, Xixian New District, Shaanxi Province, various biological detention facilities located in different types of greenbelts such as road greenbelts, residential quarters and city parks have become indirect "wetland" patches in the urban environment of semiarid areas, which have promoted the construction of environmental habitat-site diversity. Basic guidelines for designing and planting suitable ground-cover plant communities for "drought and flood" have been proposed.
The research on the habitat-site design of urban built environment focuses on finding the relationship between site space and plant community construction in the design process. Under the environmental conditions of the site, the design is aimed at how to create suitable habitat-site conditions for the inhabitation of biological communities. The control of succession development has become a key idea. Through the simulation, analysis and prediction of site habitat-site conditions, site layout organization and plant community planting, as well as continuous design to adapt to the evolution process of community morphology. This is the background of the green space ecological design theory and the habitat-site design method. It still needs a lot of scientific verification and continuous practical research.
In the current urbanization construction, ecological and social benefits are the basic needs for building a beautiful China. The construction of a beautiful China should not only carry forward the traditional Chinese culture, but also practice the "beauty" of scientific values, and build a scientific education place for the public to learn "beauty" in the living environment, so as to create beautiful "nature" around us. Beautiful China to landscape architecture is the understanding, pursuit and enjoyment of beauty by everyone and every group.
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