Among numerous vegetation studies, there are few studies on the elevation gradient distribution control mechanism and horizontal law of small-scale vegetation. In the same climate zone, topography is one of the most important factors affecting vegetation pattern. Here, we used the geo-informatic Tupu theory to construct topographic gradient-vegetation distribution information Tupu (TG-VDI Tupu) to display the topographical differentiation characteristics of vegetation. Moreover, an improved evaluation of topographical differentiation characteristics of vegetation was proposed based on topographic gradients, and the topographic composite index (TCI) was constructed to analyse the topographic variation in vegetation distribution. Meanwhile, the dominant factors and limiting factors affecting vegetation distribution under different topographic gradients were determined through statistical analysis. Combined with field surveys, Gaofen-1 (GF-1) satellite images were used to extract vegetation types, and the solar radiation value (SRV), topographic wetness index (TWI) and topographic variables were extracted from DEM data. The results indicate that TG-VDI Tupu can visually display topographic differentiation characteristics of vegetation on an elevation gradient. Elevation controls the horizontal distribution of vegetation on a small scale by changing ecological factors. At the same elevation, slope affects vegetation distribution by changing the SRV and TWI, while aspect changes the TWI. Coniferous forest is separated along a slope gradient and is more abundant on steep slopes. The percentage of broadleaf forest is negatively correlated with SRV and positively correlated with TWI, and the proportion is higher on the leeward slope facing north. The distribution of shrubs is more abundant on more xeric aspects and on steeper and more xeric slope configurations. In alpine areas above 2800 m, the abundance of vegetation types declines. This decline may be related to the weak solar radiation and widespread glacial landforms, exposed rocks and strong weathering. The methodology in our study can be applied to other regions and is expected to provide useful information for ecological conservation policy making.

中文翻译：

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基于地形梯度的阿勒泰地区植被分化特征及调控机制

在众多的植被研究中，对小尺度植被高程梯度分布控制机制和水平规律的研究较少。在同一气候带内，地形是影响植被格局的最重要因素之一。这里，我们利用地理信息图普理论构建地形梯度-植被分布信息图普（TG-VDI图普）来展示植被的地形分异特征。此外，提出了一种基于地形梯度的改进的植被地形分异特征评价方法，并构建了地形综合指数（TCI）来分析植被分布的地形变化。同时，通过统计分析确定了不同地形梯度下影响植被分布的主导因素和限制因素。结合实地调查，利用高分一号（GF-1）卫星影像提取植被类型，并从DEM数据中提取太阳辐射值（SRV）、地形湿度指数（TWI）和地形变量。结果表明，TG-VDI图普能够直观地显示植被在高程梯度上的地形分异特征。海拔通过改变生态因子来控制小尺度植被的水平分布。在同一高程下，坡度通过改变SRV和TWI影响植被分布，而坡向则改变TWI。针叶林沿坡度分开，陡坡上针叶林更为丰富。阔叶林比例与SRV呈负相关，与TWI呈正相关，且背风坡向北的比例较高。灌木的分布在越干旱的地区以及越陡峭和越干旱的斜坡构造上越丰富。在海拔2800米以上的高山地区，植被类型丰富度下降。这种下降可能与太阳辐射较弱和冰川地貌广泛、岩石裸露和强烈风化有关。我们研究的方法可以应用于其他地区，有望为生态保护政策的制定提供有用的信息。