中国三指雪莲花植被地理分布及其斑块特征

Geographical Distribution and Patch Characteristics of Saussurea tridactyla Vegetation in China

摘要: 高寒生态系统作为全球生态脆弱区的典型代表，其生态退化进程加剧与生物多样性锐减问题日趋凸显。三指雪莲花作为高寒生境的特有珍稀物种，是维持高寒生态系统结构稳定、支撑区域生物多样性的关键类群之一，具有重要的生态价值与保护意义。本研究利用ArcGIS软件，基于《中国植被图集(1:1,000,000)》获取的三指雪莲花群落分布数据，结合斑块特征和形状指数分析方法，以三指雪莲花群落为研究对象，系统探究其地理分布格局、斑块形态特征及空间分布规律的内在特征与关联。结果表明：我国三指雪莲花群落总面积为377.59 km²，总斑块数为61个，其主要集中分布于青藏高原核心区域，以西藏自治区为核心分布区，新疆南部高海拔区域有少量分布。通过空间格局分析，三指雪莲花群落呈现“小斑块数量多、大斑块占比少”的特征，斑块面积大小差异显著。不同类型三指雪莲花群落斑块的形状指数存在显著差异，这一特征反映出各类斑块与外界进行物质、能量交换的活跃程度具有明显分异。斑块扩展度与方形指数的最大值和最小值，分别出现于三指雪莲花荒漠 + 高山嵩草荒漠、三指雪莲花 + 垫状点地梅荒漠这两类群落中，且各数值均大于1，揭示了三指雪莲花不同群落类型的斑块形状均偏离圆形与方形，整体呈现不规则的形态特征，以上特征说明三指雪莲花群落的空间异质性较高，这与高海拔生境破碎化及生态因子异质性特征相契合。

Abstract: As a typical representative of global ecologically fragile regions, the alpine ecosystem is increasingly confronted with intensified ecological degradation and a sharp decline in biodiversity. Saussurea tridactyla, an endemic and rare species in alpine habitats, serves as one of the key taxa for maintaining the structural stability of alpine ecosystems and supporting regional biodiversity, thus holding significant ecological value and conservation significance. Taking Saussurea tridactyla communities as the research object, this study systematically explored the inherent characteristics and correlations of their geographical distribution patterns, patch morphological features, and spatial distribution laws by using ArcGIS software, based on the distribution data of Saussurea tridactyla communities obtained from the Vegetation Atlas of China (1:1,000,000), combined with the analysis methods of patch characteristics and shape indices. The results showed that the total area of Saussurea tridactyla communities in China was 377.59 km², with a total of 61 patches. These communities were mainly concentrated in the core area of the Qinghai-Tibet Plateau, with the Tibet Autonomous Region as the central distribution zone, and a small number of distributions were found in the high-altitude areas of southern Xinjiang. The spatial pattern analysis revealed that Saussurea tridactyla communities were characterized by a large number of small patches and a small proportion of large patches, with significant differences in patch area. There were significant differences in the shape indices of patches among different types of Saussurea tridactyla communities, a feature that reflected the obvious differentiation in the activity of material and energy exchange between various patches and the external environment. The maximum and minimum values of patch elongation index and squareness index were observed in Saussurea tridactyla desert + Kobresia pygmaea desert communities and Saussurea tridactyla + Androsace tapete desert communities, respectively, with all values greater than 1. This indicated that the patch shapes of different Saussurea tridactyla community types deviated from regular circles and squares, showing an overall irregular morphology. The above characteristics suggested a high level of spatial heterogeneity of Saussurea tridactyla communities, which was consistent with the habitat fragmentation and the heterogeneity of ecological factors in high-altitude areas.