Features of architectural landscape fragmentation in traditional villages in western Hunan, China
Uniformity characteristics of traditional village architectural landscapes
Regarding the uniformity of landscape types, a higher relative uniformity index means a greater tendency for an equal number of landscape types. Based on the index of relative evenness of architectural landscapes for the first batch of villages (Table 3, Figure 4), the amounts of each type of landscape patch, including traditional architectural style, quality and age, appear to be approximately equal. Landscape complexity was high. Indicating clear to severe fragmentation, the height of the architectural landscape shows relatively less fragmentation. For Yan Baixi Village, the architectural quality, style, age and height were in the fragmentation stage, while La Hao and Xiao Shi villages were in severe fragmentation stages. In general, villages showing severe fragmentation had equivalent amounts of each landscape type, while those with pronounced fragmentation had a particular primary landscape type and approximately the same, albeit smaller, number of other landscape types.
More specifically, (1) there are three categories of landscapes of architectural quality: good, average, and poor. Approximately 57.1% of the relative uniformity indices for landscapes of traditional architectural quality for villages fall within the range (0.7, 1) indicating relative similarity in the numbers of good, average and poor landscape types – a scenario representing extreme fragmentation. Approximately 42.9% were in the range (0.35, 0.7), indicating that the numbers of good, moderate and poor landscape types were relatively balanced, and associated with clear fragmentation (Figure 4b).
(2) In general, there are four types of architectural landscapes: cultural preservation units, historical buildings, traditional buildings (including landscaped new style buildings), and uncoordinated new buildings. The sharp and clear segmentation ratio of the architectural landscapes in the 14 villages was similar to that of the landscapes of architectural quality, indicating the general consistency across the villages. For example, the villages of Lao Dong and Yan Baixi showed clear fragmentation of architectural landscape and landscape quality, while Lao Sian, Xu Badong, Xiao Xi, La Hao, and Hang Sha showed severe fragmentation (Figure 4a).
(3) Traditional villages are characterized by four categories of architectural historical landscape: Qing Dynasty, Republican period, 1950s-1970s, 1980s, and post-1980s. About 71.4% of the historical village building landscapes were within the range (0.7, 1) in terms of relative evenness index, indicating severe fragmentation and indicating that at least three of the four chronologies had approximately the same number of buildings. Meanwhile, 28.6% were in the range (0.35, 0.7) with significant fragmentation, indicating that at least two of the four chronologies contained approximately the same number of buildings (Figure 4a).
(4) There are three types of building height views: one floor, two floors, three floors, and more than three floors. Lao Sien Village was mostly composed of a landscape of single-storey buildings, accounting for 93%, while two- and three-storey buildings were less common, resulting in low landscape fragmentation of building height. In the villages of Lao Dong, Xiao Xi, and another 50% of the other villages, the three types of building heights accounted for a certain proportion of landscape complexity, with fragmentation being severe. In 42.9% of the villages, such as Ban Li, there are primarily one- or two-story buildings and few of them are more than three stories, showing clear fragmentation (Figure 4b).
Figure 4 provides a visual representation of the architectural landscape’s relative uniformity index and diversity segmentation characteristics for each traditional village in western Hunan. Figure 4a shows the relative uniformity index for architectural style and age. Figure 4b shows the relative uniformity index for architectural quality and height.
Characteristics of the richness of the traditional village architectural landscape
In terms of landscape species richness, the higher the relative richness index, the richer the landscape type. According to the index of relative richness of the architectural landscape of the studied villages (Table 4 and Figure 5), there were three types of landscape based on the quality and height of traditional buildings and four types based on the age and style of the buildings. The various dimensions of architectural landscape types were relatively rich, the complexity of the landscape was high, and most of them showed obvious or severe fragmentation. The architectural quality, style, age and height of Lao Hao, Di Hang, Xu Jiatang and Xiao Shi were highly fragmented. In general, because the landscape types are the same and the number of landscape types are equal, the richer the landscape type, the more serious the fragmentation is.
More specifically, (1) there were three types of landscape: good, medium and poor architectural quality in all 14 traditional villages. About 85.7% of these villages showed a relative richness index of landscape architectural quality in the range (0.7, 1). The number of good, moderate, and poor landscape types was relatively uniform, with rich landscape types and extreme fragmentation. The percentage of villages with clear fragmentation reached 14.3%, and was dominated by one type of architectural quality, while the rest of the villages constituted much less than that. For example, Lao Dong and Long Bi villages had 0.9% and 0.6% poor-quality buildings, respectively (Figure 5b). (2) There were usually three or four types of architectural landscapes, of which 57.1% of villages had a relative richness index in the range of (0.7, 1), indicating severe fragmentation. In such villages, either the number of three landscape types is the same or the number of at least three of the four landscape types is relatively uniform. About 42.8% of the villages were within the range (0.35, 0.7), with clear segmentation. This type of village was dominated by a single architectural landscape type, which typically accounted for more than 75% (e.g., 75.2%, 80.2%, and 81.5% of the dominant landscape types observed in Long Bi, Lao Dong, and Yan baixi, respectively). ) (Figure 5a). (3) There are four types of landscape in all villages in the architectural chronology except for Xiao Shi, who has three types. When landscape types are consistent, the relative richness index is proportional to the relative evenness index. The higher the relative equality index, the higher the relative wealth index. Therefore, the degree of fragmentation of each village in the landscape richness index was consistent with the degree of the landscape evenness index (Figure 5a). (4) In half of the villages, including Xiao Xi, Lao Dong, and Xu Jiatang, two or three floors of buildings accounted for a higher proportion of landscape complexity, with severe fragmentation. Fifty percent of the villages, including Lao Sian and Xu Badong, showed clear segmentation, with buildings primarily one or two stories high. For example, there were no buildings with three or more floors in Lao Sian or Xu Badung (Figure 5b). Figure 5 shows the architectural landscape relative richness index and diversity segmentation characteristics of each village in traditional villages in western Hunan. Figure 5a shows the relative richness index for architectural style and age, and Figure 5b shows the relative richness index for architectural quality and height.
Heterogeneous characteristics of the architectural landscape as a whole
Regarding the landscape heterogeneity index (Table 5, Figure 6), the 14 traditional villages showed minimal fragmentation with respect to architectural quality, style and height, with values of 92.9%, 85.7% and 100%, respectively. This indicates that heterogeneous landscapes in these three dimensions have little effect on traditional landscape fragmentation. Approximately 78.6% of the age landscape heterogeneity index in the villages was in the range (1, + ∞). In other words, the number of post-1950s buildings was more than double the number of pre-1950s buildings. Thus the heterogeneous scene is much larger than the conventional scene in the time dimension, which leads to severe fragmentation. Although many new buildings have been constructed in traditional villages due to urbanization and the growth of rural tourism, these buildings are in harmony with the traditional landscape and their building heights are consistent with those of traditional buildings.
Heterogeneous characteristics of architectural landscapes in different dimensions
The heterogeneity of the architectural landscape varies across different dimensions, as the architectural era has more heterogeneous landscapes, and the architectural quality, style and height are lower.
Specifically (1) there was a “self-destructive” fragmentation of architectural landscape quality, with 92.9% of villages being in the range (0, 0.5) and 7.1% of villages being in the range (0.5, 1). In essence, most villages had fewer buildings of poor quality and a few heterogeneous architectural landscapes due to natural damage or collapse. All villages showed mild fragmentation, except for Xiao Xi, which showed obvious fragmentation (Figure 6b).
(2) As the most visually evident dimension of “heterogeneous landscape fragmentation,” the architectural style showed three instances of fragmentation; However, the heterogeneity index for each village did not differ significantly in the case of moderate fragmentation. The architectural style heterogeneity index for 85.7% of the villages was in the range (0, 0.5), and the number of modern buildings more than doubled the number of traditional buildings. Xiao Shi was fragmentary, while La Hao showed severe fragmentation in architectural style, with modern buildings more than twice as large as traditional ones (Figure 6a).
(3) Building height is the intuitive vertical dimension of “heterogeneous landscape fragmentation”, with fewer heterogeneous landscapes of three or more floors and no light fragmentation. For example, Lao Sian, Xu Badong, and Xu Jiatang consist of one- or two-story buildings without any heterogeneous impact on the landscape. The remaining villages showed slight fragmentation, with a low heterogeneity index (Figure 6b).
(4) The architectural urban landscape represents the “heterogeneous landscape fragmentation” in the temporal dimension. The fourteen traditional villages experienced three stages: mild, obvious and severe fragmentation. However, the heterogeneity index for each village varies significantly. Yan Paixi and Shou Badong were slightly segmented with heterogeneity indices of 0.2222 and 0.4483, respectively, while Lao Siyan was segmented with a heterogeneity index of 0.5435. Most villages showed a high heterogeneity index for architectural age and high fragmentation, with the highest heterogeneity observed in Ban Li, reaching 81, followed by Zhong Huang at 15.1176 (Figure 6a). Figure 6 shows the architectural landscape heterogeneity index of traditional villages in western Hunan and the heterogeneous segmentation characteristics of each village. Figure 6b shows the landscape heterogeneity index for architectural quality and height, and Figure 6a shows the landscape heterogeneity index for architectural style and age.