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Early ecological outcomes of natural regeneration and tree plantations for restoring agricultural landscapes
Author(s) -
César Ricardo G.,
Moreno Vanessa S.,
Coletta Gabriel D.,
Chazdon Robin L.,
Ferraz Silvio F. B.,
de Almeida Danilo R. A.,
Brancalion Pedro H. S.
Publication year - 2018
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1002/eap.1653
Subject(s) - eucalyptus , species richness , biomass (ecology) , abundance (ecology) , diameter at breast height , ecology , forest restoration , agroforestry , restoration ecology , vegetation (pathology) , regeneration (biology) , natural regeneration , biodiversity , forestry , biology , geography , forest ecology , ecosystem , medicine , pathology , microbiology and biotechnology
Mixed tree plantings and natural regeneration are the main restoration approaches for recovering tropical forests worldwide. Despite substantial differences in implementation costs between these methods, little is known regarding how they differ in terms of ecological outcomes, which is key information for guiding decision making and cost‐effective restoration planning. Here, we compared the early ecological outcomes of natural regeneration and tree plantations for restoring the Brazilian Atlantic Forest in agricultural landscapes. We assessed and compared vegetation structure and composition in young (7–20 yr old) mixed tree plantings ( PL ), second‐growth tropical forests established on former pastures ( SG p), on former Eucalyptus spp. plantations ( SG e), and in old‐growth reference forests (Ref). We sampled trees with diameter at breast height ( DBH) 1–5 cm (saplings) and trees at DBH > 5 cm (trees) in a total of 32 20 × 45 m plots established in these landscapes. Overall, the ecological outcomes of natural regeneration and restoration plantations were markedly different. SG e forests showed higher abundance of large ( DBH > 20 cm) nonnative species, of which 98% were resprouting Eucalyptus trees, than SG p and PL , and higher total aboveground biomass; however, aboveground biomass of native species was higher in PL than in SG e. PL forests had lower abundance of native saplings and lianas than both naturally established second‐growth forests, and lower proportion of animal dispersed saplings than SG e, probably due to higher isolation from native forest remnants. Rarefied species richness of trees was lower in SG p, intermediate in SG e and Ref and higher in PL , whereas rarefied species richness of saplings was higher in SG than in Ref. Species composition differed considerably among regeneration types. Although these forests are inevitably bound to specific landscape contexts and may present varying outcomes as they develop through longer time frames, the ecological particularities of forests established through different restoration approaches indicate that naturally established forests may not show similar outcomes to mixed tree plantings. The results of this study underscore the importance that restoration decisions need to be based on more robust expectations of outcomes that allow for a better analysis of the cost‐effectiveness of different restoration approaches before scaling‐up forest restoration in the tropics.