Recolonization of secondary forests by locally extinct fauna through the lens of range expansion: Four open questions

Abstract

Recolonization of secondary forests happens when individuals disperse from a nearby source old-growth forest populations. This pattern of recolonization could be (a) the result of a random subset of individuals dispersing and colonizing nearby secondary habitats. Instead, the set of recolonizing individuals may not be random but have a particular set of characteristics. (b) Old-growth source populations could show spatial sorting where highly dispersive individuals (those with larger limbs, or exploratory and aggressive behavior) are overrepresented in the forest patch edges and more likely to colonize nearby patches. These are often known as “pull” expansions because highly dispersive individuals living at the edge of the source population are the ones “pulling” the expansion. Alternatively, (c) because old-growth populations are expected to be at carrying capacity recolonization may be driven by subordinate individuals that cannot outcompete dominant conspecifics and disperse looking for alternative territories. This is the case of “push” expansions when dispersal is driven by these subordinate individuals that are pushed away due to density dependence.