基于地形因子的千米尺度景观生态廊道布局研究

土地利用类型并不是景观类型唯一的描述方式, 生态服务价值的估算和地形指标的纳入更有助于反映景观的空间差异性。应用地形因子与生态价值两类指标, 对关中-天水经济区1 km栅格尺度下生态廊道空间布局形式进行研究, 结果如下:① 相关性分析表明地形因子对生态价值分布有重要影响, 经过统一阈值的脊线谷线提取发现, 对生态价值提取出的高值或低值区域几乎同时也是地形上的山脊线或山谷线, 过渡带基本重合;② 提取山脊生态高值区域作为生境斑块, 通过最大生态阻力进行方向选择, 可得出研究区生态廊道空间布局, 由于廊道宽度可根据物种类型调整, 同时距离较短导致实现难度低, 增删节点与斑块不影响周边网络的拓扑关系, 因此结果应用性相对更强;③ 采用地形和生态服务价值作为衡量指标, 更能体现以像元为单位的景观功能一致性与差异性, 从而也避免了土地利用分类较粗、生境判断难度较大、相同阻力路径过多等一系列问题。本文结果是对千米尺度廊道布局的有效补充。

Kilometer-scale layout of ecological landscape corridors based on terrain factors

Landscape ecological corridor planning is an important method to protect biodiversity. Land use type is not the only index to describe landscape forms. Taking the estimation of ecological service value as well as terrain index into account helps better reflect the spatial variations of landscapes. In this paper, based on ecological service value and terrain factors, the layout of ecological landscape corridors in Guan-Tian economic region is analyzed with a grid resolution of 1 km. The results are shown as follows: (1) Correlation analysis shows that terrain factors have a significant impact on the distribution of ecological value. When the ridges and valleys are extracted using the unified threshold, it is found that the areas with high or low ecological values are ridges or valleys of the terrain as well; the transition zones superimpose very well. (2) The ridges with high ecological value are extracted as habitat patches, then the layout of ecological corridors is modeled in space by choosing the direction through the areas with the biggest ecological resistance. Since the corridor width can be adjusted based on the species types, the relatively short length of the corridors makes it easier to construct, and adding or removing nodes and patches doesn’t affect the topological relationship between each corridor and the surrounding network, the applicability of the modeling results is relatively high. (3) As mentioned above, using ecological service value and terrain factors help better reflect the similarities and differences of the landscape functions of the pixel unit, and also helps avoid the problems such as land use classifications being too broadly defined, identifications of habitat patches being too difficult, and the paths with similar ecological resistance being too many, etc. All in all, the work presented in this paper is an effective supplement to the design of ecological corridors in a kilometer scale, and at the same time, demonstrates the necessity to develop the methods for the studies of ecological aspects of the landscapes in specific regions, under the background of dramatic differences of the geographic features between the east and the west of China.