积雪地形分异对植被垂直带格局及演化的影响

Snow cover is the key site condition that affects mountain vegetation distribution and controlled by topography on the local scale. The effect of snow cover topographical features on altitudinal belts pattern are critical to understanding altitudinal belt dynamics and future changes. However, these effects have not been understood quite well enough because of low data resolution. In this study, We will use artificial neural network principle to estimate fractional snow cover in complex mountain environments on the local scale and then summarize the topographic variation pattern of snow cover combine field survey data, find out the key snow cover feature which affect vegetation distribution and restrain forest move to high elevation. By build the function between vegetation pattern and ecological factors especially snow cover, we can reveal the mechanism of snow cover topographical features on the Changbai Mountain altitudinal belts and then predict the change trend under future climate change. The results from this study are significance for understand how altitudinal belts respond to climate systems and can provide measures of protecting eco-environment on the Changbai Mountain.

积雪是影响山地植被分布的重要立地条件且在局域尺度受地形控制。研究积雪地形分异对垂直带格局的影响机制有助于更精确的预测垂直带格局随全球气候变化的演变趋势。然而，缺乏高空间分辨率积雪分布数据阻碍了积雪对山地植被格局影响的定量分析及建模。本项目以垂直带性典型区——长白山垂直带为研究对象，采用遥感影像人工神经网络分类和野外调查相结合的方法，研究山地局域尺度亚像元积雪覆盖提取技术，分析积雪地形分异规律，确定影响植被分布和限制森林上侵的积雪属性，构建植被分布与积雪等生态因子的关系方程。项目预期将定量揭示积雪地形分异对长白山垂直带格局的作用机制，预测未来气候变化情景下垂直带格局变化趋势。项目的研究成果对于深化垂直带格局对全球气候响应研究具有重要意义，为制定区域应对措施、保护长白山生态环境提供科学依据。

积雪是影响山地植被分布的重要立地条件且在局域尺度受地形控制。研究积雪地形分异对垂直带格局的影响机制有助于更精确的预测垂直带格局随全球气候变化的演变趋势。然而，缺乏高空间分辨率积雪分布数据阻碍了积雪对山地植被格局影响的定量分析和建模。本项目以长白山垂直带为研究对象，采用遥感影像人工神经网络分类和野外调查相结合的方法，研究积雪地形分异对植被垂直带格局及演化的影响。具体为：（1）研究了山地亚像元积雪覆盖提取的技术要点，获得了亚像元积雪覆盖产品。（2）阐明了长白山积雪属性的地形分异规律。由北坡到西坡再到南坡，积雪初日逐渐提前，融雪终日延后，积雪期变长，雪深增加。同一海拔坡度越高积雪覆盖率越低。高山带积雪分布呈两极化，积雪地形分异最复杂；（3）确定了影响植被分布和限制森林上侵的积雪属性；（4）拟合了各植被带与积雪等生态因子的数量关系；（5）基于未来气候情景预测了垂直带格局演变趋势。垂直带谱整体向高海拔移动，林线上升，树种限不变，树线过渡带变窄。（6）尝试从土壤角度探讨了积雪对垂直带格局的影响。积雪深度随海拔升高使得土壤温度的海拔梯度变化远小于气温的梯度变化，甚至使带内土壤温度接近相同。项目成果可为深化垂直带格局对全球气候变化响应研究提供理论参考，为制定区域应对措施、保护长白山生态环境提供科学依据。