基于无人机航测的漯河市土地利用景观格局尺度效应

景观格局的尺度效应一直是景观生态学研究的核心内容,对于揭示景观空间格局变化规律及其生态过程具有重要意义。以漯河市中心城区为研究对象,基于景观生态学原理,采用无人机航测技术获取空间分辨率为0.09 m的无人机影像,结合GIS空间分析法,量化分析了漯河市土地利用景观格局的尺度效应。结果表明:(1)漯河市中心城区土地利用景观格局具有明显的粒度和幅度效应。(2)粒度越小,景观格局指数随空间粒度的变化趋势越稳定,其表达的生态过程越真实;景观水平上景观格局的粒度效应是由建筑、道路和绿地景观在景观优势度、破碎度和聚集度等方面的变化导致的;35 m和3 m分别为研究粒度效应的临界阈值和最佳粒度。(3)景观优势度、破碎度和蔓延度随空间幅度的增加而降低,景观复杂程度和聚集度随空间幅度的增加而增加;景观格局具有明显的空间梯度分布特征——从市中心往外由不透水地面向透水地面过渡;建筑和道路在城市中心区聚集度较高,而绿地景观在城市内部破碎度较高,进而主导了整体景观格局的梯度变化;景观组分的稳定与城市规模有关。(4)无人机航测技术可以更快速、准确地获取城市尺度上的景观生态信息,揭示景观格局对尺度效应的响应特征,可为景观格局优化和城乡景观规划提供科学依据。

Scale effects on land use patterns in Luohe City based on an unmanned aerial vehicle survey

The scale effects on landscape patterns are not only crucial for determining characteristics of change and ecological processes in the landscape patterns, but also a major issue in landscape ecology research. Unmanned aerial vehicle (UAV) imagery has great potential for the study of scale effects on urban landscape patterns because of its high spatial resolution, versatility, and remarkable operational improvements in recent years. In this study, the landscape classes of urban land use were extracted from UAV imagery of Luohe central city with 0.09 m spatial resolution based on Geographic Information System (GIS) techniques. The scale effects on land use patterns were quantified by using FRAGSTATS 4.2 and principles of landscape ecology. The results were as follows:(1) The landscape indexes were sensitive to the variance of grain and extent. (2) The smaller the spatial grain size was, the more stable the change trend of the landscape indexes was, which usually brought more realistic processes of ecology in the landscape patterns; the grain size effect on landscape patterns at the landscape level was mainly caused by the changes of landscape dominance, fragmentation, and aggregation of buildings, roads, and green land; 35 m was the largest threshold of spatial grain size, whereas 3 m was the optimal spatial grain size during the study of grain size effect. (3) The landscape dominance, fragmentation, and contagion decreased, whereas the landscape complexity and aggregation increased with the increase in spatial extent; the landscape patterns had obvious spatial gradient distribution characteristics, with the transition from impermeable soil surfaces in the central city to the permeable soil surfaces in the outside city; the aggregation of buildings and roads was higher in the central city area, whereas the fragmentation of green land was higher in the city, and all of these factors led to the gradient change in the landscape patterns at the landscape level; the stability of the landscape components was related to the city scale. (4) The UAV survey technology could generate urban landscape ecological information with accuracy and efficiency, reveal the response characteristics of the scale effects on landscape patterns, and provide a scientific basis for the optimization of landscape patterns and the planning of the urban-rural landscape.