Data from: Active restoration accelerates recovery of tropical forest bird assemblages over two decades

Choosing effective methods to restore habitat for the diverse faunal
assemblages of tropical forests is hampered by lack of long-term data
comparing multiple restoration treatments. We conducted area counts of
bird assemblages over 12 years (~5-17 years since restoration) in a
blocked experiment with two active planted treatments (tree plantations
and applied nucleation) and a passive restoration treatment (natural
regeneration) replicated at 11 sites in Costa Rica. We also surveyed six
pastures and five remnant forest sites to assess recovery of avian species
richness, composition, forest specialists, and range-restricted species in
restoration plots relative to degraded and reference systems. Restoration
treatments showed increased resemblance of avian assemblages to remnant
forest over time. Applied nucleation proved equally effective as
plantation, despite a reduced planted area, whereas natural regeneration
recovered more slowly. Assemblage-level trends in avian species richness
and compositional similarity to reference forest are underpinned by
reductions in use by pasture birds and by gradual increases in richness of
forest-affiliated species. Because forest-affiliated species tend to have
narrower distributions than the open-country species they replace, forest
restoration can reduce biotic homogenization at the local scale.
Restoration practitioners should consider applied nucleation as an
alternative to standard plantations if seeking rapid recovery of bird
assemblages. However, the ecological return on investment from natural
regeneration increases over a couple of decades. Managers should monitor
trends in forest-affiliated and range-restricted species to track the
recovery of the full avian assemblages, since coarse metrics like species
richness and overall compositional similarity may plateau relatively
quickly.