Coda
National and international policies have embraced the principle of conserving 30% of land and water by 2030. To protect biodiversity, this so-called ‘30×30’ must be achieved in each ecoregion. This can be achieved through conservation of the large habitat areas that resemble wilderness, combined with protection and restoration of many small habitat patches in ecoregions severely affected by human activities. In fact, in heavily populated and highly human-modified regions, reaching area targets will be possible only through protection of small patches and habitat restoration. In such regions, new conservation of many small areas is essential to get to 30×30, and such areas may represent the greatest net gains for conservation going forward.
More broadly, realizing 30×30 and other ambitious, collective, area-based plans will be possible only if we recognize that common ground far exceeds disagreement among researchers working on area-based biodiversity conservation. All sides agree that reversing biodiversity declines cannot be accomplished without conservation and restoration of native habitat, especially in regions where most native habitat is already gone. The disagreements are secondary to the general principles we outline in this letter, and we are confident that they will be resolved as data accumulate and science progresses. In the meantime, to address a global biodiversity emergency, proactive implementation of the unequivocal principles that we all agree upon will bolster our chances of preserving the Earth’s biodiversity heritage.
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Acknowledgments:
Author contributions:Conceptualization: FR, NH, LF, CBL Visualization: FR, NH, LF, CBL Writing – original draft: FR, CBL Writing – review & editing: FR, NH, LF, CBLCompeting interests:Authors declare that they have no competing interests.Data and materials availability:No data analysis presented in this Policy Forum
Supplementary Materials
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Fig. 1. Three principles for area-based biodiversity conservation. (1) To protect Earth’s biodiversity, we must protect and restore native habitat in all biomes and ecoregions. Shown are Earth’s 14 biomes. (2) Protecting as much native habitat as possible is our best way to safeguard biodiversity, and requires protecting both smaller and larger patches. For instance, while in some tropical biomes forest may exist in large, continuous patches, other biomes have been reduced to highly fragmented habitat. Green circles represent habitat patches separated by anthropogenic land use in two adjacent biomes (green and blue background); the fading, green area on the bottom-left corner of the inset represents a large expanse of wilderness. (3) Habitat patches must be functionally connected. Habitat connectivity can increase with stepping stone habitat (a), corridors (b), or by reducing distances between patches (i.e., increasing patch density in the landscape) (c).