DOI: 10.5061/dryad.zcrjdfnd4
title: A global meta-analysis of the impacts of tree plantations on biodiversity

description: Aim: Planted forests are becoming increasingly common worldwide for a
 variety of reasons including water conservation and carbon sequestration,
 whereas the effects of tree plantations on biodiversity are unclear as to
 whether planted ecosystems are ‘green deserts’ or valuable habitats for
 biodiversity. Location: Global. Time period: 1980–2020. Taxa studied:
 Flora, fauna, and microorganisms. Methods: By conducting a meta-analysis
 of 361 observations from 138 sites worldwide, we explored the global
 patterns and associated drivers of biodiversity responding to tree
 plantations by comparing biodiversity levels in plantations and adjacent
 habitats (primary or secondary forests). Results: Overall, the
 biodiversity (species richness) and abundance across multi-trophic levels
 in tree plantations was lower than that in primary forests, reached
 similar values to secondary succession, but varied with plantation and
 management regimes. Specifically, the biodiversity across multi-trophic
 levels in reforestation was higher than that in afforestation; the
 biodiversity in mixture, native species, and unmanaged plantations was
 higher than that in monoculture, exotic species, and managed plantations.
 The diversity of vertebrates, invertebrates, and plants in reforestation
 was lower than that in primary forests, while belowground biodiversity in
 reforestation showed no difference with primary forests. Invertebrate
 diversity in reforestation was lower than that in secondary succession,
 whereas plant diversity was higher than that in secondary succession.
 Moreover, the biodiversity in reforestation increased with reforestation
 age. Furthermore, structural equation models showed that aboveground
 faunal diversity in reforestation was driven by canopy coverage and plant
 diversity, reforestation affected belowground biodiversity mainly by
 changing soil organic carbon. Main conclusions: Our findings suggesting
 that reforestation by planting mixed native species will be more
 beneficial to biodiversity, revealing that biodiversity in intensive
 managed plantations was significantly lower than restoration-oriented
 plantations, and highlighting that primary forests are not replaceable,
 but planted forests may be a reliable way to rapidly restore biodiversity.
description: To investigate the effects of tree plantations on biodiversity
 through evaluating differences in biodiversity between tree plantations
 and adjacent habitats, we searched for all peer-reviewed publications
 using ISI Web of Science (isiknowledge.com) and China National Knowledge
 Infrastructure (CNKI, www.cnki.net) between 1980 and 2020. The keywords
 and terms used were (“planting” OR “tree plant*” OR “plantation*” OR
 “afforestation” OR “reforestation”) AND (“diversity” OR “richness” OR
 “abundance”). The following criteria were applied to select studies: 1)
 experiments conducted in the field that reported the effects of tree
 plantations on biodiversity and 2) experiments that had at least one pair
 of data points comparing tree plantations vs. adjacent ecosystem types
 (e.g., primary and secondary forests) and that reported standard
 deviations/errors or numbers of replicates (Fig. S1). Means, standard
 deviations/errors, and sample sizes were extracted from tables or
 digitized graphs using GetData Graph Digitizer (ver. 2.24, www.getdata-graph-digitizer.com/). The Worldclim database at http://worldclim.org was used to extract mean annual precipitation (MAP) and temperature (MAT) using the location information (latitude and longitude). Since some publications investigated more than one site within a study, the number of study sites (138, Fig. S2) was higher than that of publications (110, Table S1). Overall, a total of 138 sites, reporting 26 Family belong to 11 Class/Phyla (Table S2), and 361 observations were selected in our meta-analysis (Fig. S3).