Composition and Diversity of Woody Plants in Tree Plantations Versus Secondary Forests in Costa Rican Lowlands

Abstract

Efforts to sequester carbon through tree plantations and natural regeneration in the tropics may also provide an opportunity to restore native forest ecosystems. However, the degree to which species composition of native species differs between tree plantations and secondary forests is unknown. In this study, we conducted surveys of woody plants (≥2 cm dbh) in 20 secondary forest and tree plantation plots (30 × 30 m) in a tropical lowland forest landscape. Sites were 8 to 21 years old and were either abandoned cattle pastures (secondary forests) or monoculture tree plantations (Hieronyma alchorneoides and Vochysia guatemalensis) planted for carbon sequestration. We compared species composition, ecological traits, and diversity of woody plants in secondary forests and tree plantations, while accounting for distance from primary forest. Species composition, but not species richness, of the natural regeneration was significantly different in tree plantations and secondary forests. The abundances of understory species, short-lived pioneers, and bat-dispersed species were all higher in secondary forests than in tree plantations. Abundances of canopy species, long-lived pioneers, shade-tolerant species, and dispersal categories besides bats were not associated with forest type. We conclude that tree plantations can alter species composition of regeneration compared with secondary forests perhaps by altering composition of seed disperser assemblages or inhibiting early successional species.