Pelletier David, Lapointe Marc-Élie, Wulder Michael A, White Joanne C, Cardille Jeffrey A
Department of Natural Resource Sciences and McGill School of Environment, McGill University, Montreal, QC, Canada.
Département de Mathématiques, Collège Montmorency, Laval, QC, Canada.
PLoS One. 2017 Feb 1;12(2):e0169428. doi: 10.1371/journal.pone.0169428. eCollection 2017.
Ecological processes are increasingly well understood over smaller areas, yet information regarding interconnections and the hierarchical nature of ecosystems remains less studied and understood. Information on connectivity over large areas with high resolution source information provides for both local detail and regional context. The emerging capacity to apply circuit theory to create maps of omnidirectional connectivity provides an opportunity for improved and quantitative depictions of forest connectivity, supporting the formation and testing of hypotheses about the density of animal movement, ecosystem structure, and related links to natural and anthropogenic forces. In this research, our goal was to delineate regions where connectivity regimes are similar across the boreal region of Canada using new quantitative analyses for characterizing connectivity over large areas (e.g., millions of hectares). Utilizing the Earth Observation for Sustainable Development of forests (EOSD) circa 2000 Landsat-derived land-cover map, we created and analyzed a national-scale map of omnidirectional forest connectivity at 25m resolution over 10000 tiles of 625 km2 each, spanning the forested regions of Canada. Using image recognition software to detect corridors, pinch points, and barriers to movements at multiple spatial scales in each tile, we developed a simple measure of the structural complexity of connectivity patterns in omnidirectional connectivity maps. We then mapped the Circuitscape resistance distance measure and used it in conjunction with the complexity data to study connectivity characteristics in each forested ecozone. Ecozone boundaries masked substantial systematic patterns in connectivity characteristics that are uncovered using a new classification of connectivity patterns that revealed six clear groups of forest connectivity patterns found in Canada. The resulting maps allow exploration of omnidirectional forest connectivity patterns at full resolution while permitting quantitative analyses of connectivity over broad areas, informing modeling, planning and monitoring efforts.
在较小区域内,生态过程越来越为人所熟知,然而,关于生态系统的相互联系和层次性质的信息,仍有待深入研究和理解。具有高分辨率源信息的大面积连通性信息,既提供了局部细节,也呈现了区域背景。将电路理论应用于创建全向连通性地图的新兴能力,为改进和定量描述森林连通性提供了契机,有助于形成和检验关于动物移动密度、生态系统结构以及与自然和人为力量相关联系的假设。在本研究中,我们的目标是利用新的定量分析方法,描绘加拿大北方地区连通性状况相似的区域,这些方法用于表征大面积(例如数百万公顷)的连通性。利用2000年前后森林可持续发展地球观测(EOSD)计划中Landsat卫星获取的土地覆盖图,我们创建并分析了一幅全国尺度的全向森林连通性地图,分辨率为25米,覆盖了加拿大森林地区的10000个面积为625平方公里的图块。通过图像识别软件在每个图块的多个空间尺度上检测廊道、瓶颈点和移动障碍,我们开发了一种简单的方法来衡量全向连通性地图中连通性模式的结构复杂性。然后,我们绘制了Circuitscape电阻距离测量图,并将其与复杂性数据结合使用,以研究每个森林生态区的连通性特征。生态区边界掩盖了连通性特征中的大量系统模式,而使用一种新的连通性模式分类方法则揭示了加拿大发现的六种清晰的森林连通性模式组。由此生成的地图允许在全分辨率下探索全向森林连通性模式,同时允许对大面积的连通性进行定量分析,为建模、规划和监测工作提供信息。