Logging roads are a large cause of edge effects in forests. The greater the distance between patches, the more difficult it is for individuals in a population to migrate. Consequently, the conservation value of isolated forest patches will be lessened if particular species abstain from crossing open areas to reach other fragment remnants. One way to remedy this situation may be through secondary forests. They might form valuable corridors that would increase connectedness of original fragments and sustain higher rates of immigration.
Most studies fail to specify the precise placement of edges.
Two of the possible defining characteristics are the point of edge creation, where forest tree trunks of the primary forest reach, and the point of edge maintenance, or limit of undergrowth. Previous studies have suggested that mowing vegetation functionally converts suitable small mammal habitats to unsuitable ones. Bowers et al . The importance of edge increases as fragment size decreases. Some smaller fragments may even be all edge, because their size does not support a core forest habitat of primary species.