Active or Passive Forest Restoration? Assessing Restoration Alternatives with Avian Foraging Behavior

Active and passive restoration are two important strategies to aid the recovery of large areas of deforested and degraded tropical lands. Active restoration is where management techniques such as planting seeds or seedlings are implemented, and passive restoration is when no action is taken except to cease environmental stressors such as agriculture or grazing. We compared the habitat quality of active and passive restoration sites with similar land-use histories and times since abandonment for insectivorous birds by measuring vegetation structure, arthropod biomass, and the foraging behavior of three resident bird species in southern Costa Rica. Although vegetation measures such as amount of understory cover and tree species richness and density differed between the two restoration strategies, arthropod biomass and foraging behavioral measures were similar. Our results suggest that while active and passive restoration strategies may lead to different vegetation structures, they may support similar biomass of foliage-dwelling arthropods and be similarly used by foraging insectivorous birds. Passive restoration is generally less costlier than active restoration and, if local and landscape characteristics do not impede recovery, may be a viable alternative from the perspective of birds using the sites.