Science 30 January 2015:
Vol. 347 no. 6221 pp. 484-485
DOI: 10.1126/science.347.6221.484-c
* LETTERS
>Tyranny of trees in grassy biomes
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>Highland grassland in Brazil is considered a forest landscape restoration
>opportunity
>PHOTO: G. W. FERNANDES
>Tree planting, fire suppression, and exclusion of megafaunal herbivores
>(native or domestic) are ecologically reasonable restoration strategies in
>deforested landscapes, but similar interventions can be catastrophic when
>applied to grassy biomes such as grasslands, savannas, and open-canopy
>woodlands (1). As hopes grow that carbon payment schemes will finance forest
>restoration (2), we must clearly distinguish between “reforestation”—planting
>trees on deforested land—and “afforestation”—converting historically nonforest
>lands to forests or tree plantations (3). Afforestation of grassy biomes can
>severely compromise ecosystem services, including hydrology (4) and soil
>nutrient cycles (5), and markedly reduce biodiversity (6).
>Despite these high environmental costs, grassy biomes, particularly those with
>seasonally dry tropical climates, are prime targets for carbon sequestration
>programs that emphasize tree planting (1, 7). Threats of afforestation and
>agricultural conversion are exacerbated because the grassy biomes are not
>formally recognized by the United Nations (UN) Framework Convention on Climate
>Change, the program for Reducing Emissions from Deforestation and Forest
>Degradation (REDD+), or the UN Food and Agriculture Organization. This lack of
>recognition reflects fundamental misperceptions about the ecology,
>conservation values, locations, and antiquity of the grassy biomes.
>The World Resources Institute's (WRI's) map of “Forest and Landscape
>Restoration Opportunities” (2) serves as an example of these misperceptions.
>The map identifies 23 million km2 of the terrestrial biosphere as highly
>suitable for tree planting. Yet much of the area targeted for “forest
>restoration” corresponds to the world's ancient grassy biomes. The WRI
>erroneously assumes that nonforest areas where climate could theoretically
>permit forest development are “deforested,” an assumption rooted in outdated
>ideas about potential vegetation and the roles of fire and herbivores in
>natural systems (8). This map is intended as a tool to help meet the Bonn
>Challenge to “restore 150 million hectares of the world's deforested and
>degraded lands by 2020.” Although many ecosystems within the grassy biomes
>might benefit from ecological restoration, the restoration strategies proposed
>by WRI (2) are incompatible with grassland biodiversity.
>Meanwhile, among the landscapes correctly identified as deforested by the WRI
>map, extensive areas of agriculture are not considered restoration
>opportunities (2). Clearly, the economic output of agricultural lands makes
>them expensive to reforest. But attempts to offset agricultural deforestation
>through afforestation of the grassy biomes will simply worsen biodiversity
>losses and further compromise ecosystem services.
>The “Forest and Landscape Restoration Opportunities” map was produced and
>presumably vetted by influential scientific and environmental organizations,
>which lends it legitimacy. WRI (2) collaborated with and/or was supported by
>the International Union for the Conservation of Nature, the Global Partnership
>on Forest and Landscape Restoration, the Program on Forests, the University of
>Maryland, South Dakota State University, the German Ministry for the
>Environment, and the Forestry Commission of Great Britain. The producers of
>the map also acknowledge receiving review comments from the UN Environment
>Programme–World Conservation Monitoring Center.
>That such a scientifically flawed analysis is poised to promote misinformed
>tree planting is emblematic of deep misunderstandings about the grassy biomes,
>as well as their devaluation relative to forests. We worry that so long as
>tree planting is viewed as innately good and the grassy biomes are assumed to
>be the result of deforestation, afforestation projects will face limited
>public resistance and analyses such as this WRI map will escape scientific
>scrutiny. Deforestation and forest degradation are critical problems that must
>be addressed, but with due consideration of the value of the many naturally
>nonforest biomes that also face tremendous pressure from human-caused
>environmental change.
> 1. Joseph W. Veldman1,*, 2. Gerhard E. Overbeck2, 3.
> Daniel Negreiros3, 4. Gregory Mahy4, 5. Soizig Le Stradic4, 6. G.
> Wilson Fernandes3,5, 7. Giselda Durigan6, 8. Elise Buisson7, 9.
> Francis E. Putz8, 10. William J. Bond9
> 1. 1Department of Ecology, Evolution, and Organismal Biology, Iowa
> State University, Ames, IA 50011, USA.
> 2. 2Department of Botany, Universidade Federal do Rio Grande do Sul,
> Porto Alegre, RS, 91501-970, Brazil.
> 3. 3Ecologia Evolutiva e Biodiversidade, Universidade Federal de Minas
> Gerais, Belo Horizonte, MG, 30161-901, Brazil.
> 4. 4Gembloux Agro-Bio Tech, Biodiversity and Landscape unit, University
> of Liege, Gembloux, 5030, Belgium.
> 5. 5Department of Biology, Stanford University, Stanford, CA 94305, USA.
> 6. 6Laboratório de Ecologia e Hidrologia Florestal, Floresta Estadual
> de Assis, Instituto Florestal, Assis, SP, 19802-970, Brazil.
> 7. 7Institut Méditerranéen de Biodiversité et d'Ecologie marine et
> continentale (IMBE), Université d'Avignon et des Pays de Vaucluse, Avignon,
> 84911, France.
> 8. 8Department of Biology, University of Florida, Gainesville, FL
> 32611, USA.
> 9. 9Department of Biological Sciences, University of Cape Town and
> South African Environmental Observation Network, NRF, Rondebosch, 7701, South
> Africa.
> 1. ↵*Corresponding author. E-mail: [email protected]
>REFERENCES
> 1. ↵ 1. C. L. Parr 2. et al., Trends Ecol. Evol. 29, 205 (2014).
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> 2. ↵ WRI, “Atlas of Forest and Landscape Restoration Opportunities”
> (World Resources Institute,Washington, DC, 2014);
> www.wri.org/resources/maps/atlas-forest-and-landscape-restoration-opportunities/.
> 3. ↵ 1. F. E. Putz, 2. K. H. Redford, Glob. Environ. Change 19, 400
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> 4. ↵ 1. R. B. Jackson 2. et al., Science 310, 1944 (2005).
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> 7. ↵ United Nations Framework Convention on Climate Change, CDM
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> 8. ↵ 1. W. J. Bond, 2. F. I. Woodward, 3. G. F. Midgley, New
> Phytol. 165, 525 (2005). CrossRefMedlineWeb of ScienceGoogle Scholar
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