Landscape fragmentation Effective Mesh Size: major anthropogenic fragmenting elements (FGA1-M), version 2.0, Nov. 2016

The raster file is the basis of the indicator for assessing landscape fragmentation due to urban and transport expansion, considering major roads only. The computation is based on the method of Effective Mesh Size (meff, Jaeger 2000). The effective mesh size (meff) can be interpreted as the area that is accessible to animals when starting a movement at a randomly chosen point inside a landscape without encountering a physical barrier. The meff expresses the probability that any two points chosen randomly in an area are connected, that is, not separated by the barriers of a Fragmentation Geometry (FG) such as transport routes or built-up areas. Hence, meff is a measure of landscape connectivity, i.e. the degree to which movements between different parts of the landscape are possible. The meff is measured as an area (km2), within the cells of a 1 km2 regular grid as reporting units.本栅格文件（raster file）是评估城市与交通扩张导致的景观破碎化指标的基础，仅考虑主要道路。其计算采用有效网格尺度（Effective Mesh Size，meff；Jaeger 2000）方法。有效网格尺度（meff）可解释为：动物在景观内随机选取一点出发且未遭遇物理屏障时，所能活动的连续区域面积。meff表征某区域内任意两个随机选取的点相互连通的概率，即两点未被破碎化几何（Fragmentation Geometry，FG）类屏障（如交通廊道或建成区）所分隔。因此，meff是衡量景观连通性的指标，反映景观不同区域间实现移动的可行程度。meff以面积（平方千米，km²）为计量单位，统计报告单元为1平方千米规则网格的栅格单元。