Positive site selection bias in meta-analyses comparing natural regeneration to active forest restoration

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Science Advances  16 May 2018:
Vol. 4, no. 5, eaas9143
DOI: 10.1126/sciadv.aas9143

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  • Response to Crouzeilles et al.
    • J. Leighton Reid, Assistant Scientist, Missouri Botanical Garden
    • Other Contributors:
      • Matthew E. Fagan, Assistant Professor, University of Maryland Baltimore County
      • Rakan A. Zahawi, Lyon Arboretum Director, University of Hawaii at Mānoa

    We are glad that our colleagues agree with our criticism that there is positive selection bias in previous meta-analyses. However, our main point is lost in their response and bears reiteration. Chronosequence studies are not comparable to tree planting studies. The reason is methodological. Secondary forest chronosequence sites are selected from a pool of sites where forest recovery occurred, whereas tree planting sites are selected from a pool of non-forest sites. As such, chronosequence studies bypass a strong filter; namely, these studies exclude sites where natural regeneration was stalled in a non-forested state. Tree planting studies do pass through this filter, and as such they are at an inescapable disadvantage that is unrelated to site age, landscape forest cover, previous land use history, climatic conditions, and many other environmental factors.

    While reporting bias may exist for both secondary forests and tree planting, the former bias is demonstrable, but the latter bias is only alleged. It is possible that negative results from tree planting studies could be under-represented in the literature, but in many cases tree planting studies are designed to compare different strategies and determine which had greater relative success. In this typical situation, poor forest development in one or more treatments would constitute positive, publishable results. A rigorous evaluation of publishing bias in active tropical forest restoration studies would be welcom...

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    Competing Interests: None declared.
  • RE: Comment on “Positive site selection bias in meta-analyses comparing natural regeneration to active forest restoration”

    Authors: Renato Crouzeilles1,2,3*, David B. Lindenmayer4, Jerônimo B. B. Sansevero5, Mariana S. Ferreira6,7, Alvaro Iribarrem1,2, Bernardo B. N. Strassburg1,2,3, Robin L. Chazdon1,8

    1International Institute for Sustainability, 22460-320, Rio de Janeiro, Brazil.
    2Rio Conservation and Sustainability Science Centre, Department of Geography and the Environment, Pontifícia Universidade Católica, 22453-900, Rio de Janeiro, Brazil.
    3Programa de Pós Graduação em Ecologia, Universidade Federal do Rio de Janeiro, 68020, Rio de Janeiro, Brazil.
    4Fenner School of Environment and Society, The Australian National University, 2601 Canberra, Australia.
    5Department of Environmental Sciences, Universidade Federal Rural do Rio de Janeiro, 23890-000, Rio de Janeiro, Brazil.
    6Laboratory of Vertebrates, Department of Ecology, Universidade Federal do Rio de Janeiro, 68020, Rio de Janeiro, Brazil.
    7Mestrado Profissional em Ciências do Meio Ambiente, Universidade Veiga de Almeida, 20271-901, Rio de Janeiro, Brazil.
    8Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT USA.

    *Correspondence to:
    Renato Crouzeilles
    Estrada Dona Castorina 124, 22460-320, Rio de Janeiro, Brazil
    +55 21 988982865


    We agree with Reid et al. (Reviews, 4 May 2018, eaas9143), there may be positive...

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    Competing Interests: None declared.

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