The Convention on Biological Diversity's (CBD) strategic plan will expire in 2020, but biodiversity loss is ongoing. Scientists call for more ambitious targets in the next agreement. The nature-needs-half movement, for example, has advocated conserving half of Earth to solve the biodiversity crisis, which has been translated to protecting 50% of each ecoregion. We evaluated current protection levels of ecoregions in the territory of one of the CBD's signatories, the European Union (EU). We also explored the possible enlargement of the Natura 2000 network to implement 30% or 50% ecoregion coverage in the EU member states' protected area (PA) network. Based on the most recent land-use data, we examined whether ecoregions have enough natural area left to reach such high coverage targets. We used a spatially explicit mixed integer programing model to estimate the least-cost expansion of the PA network based on 3 scenarios that put different emphasis on total conservation cost, ecological representation of ecosystems or emphasize an equal share of the burden among member states. To realize 30% and 50% ecoregion coverage, the EU would need to add 6.6% and 24.2%, respectively, of its terrestrial area to its PA network. For all 3 scenarios, the EU would need to designate most recommended new PAs in seminatural forests and other semi- or natural ecosystems. Because 15 ecoregions did not have enough natural area left to implement the ecoregion-coverage targets, some member states would also need to establish new PAs on productive land, allocating the largest share to arable land. Thirty percent ecoregion coverage was met by protecting remaining natural areas in all ecoregions except three, where productive land would also need to be included. Our results support discussions of higher ecoregions protection targets for post-2020 biodiversity frameworks. Article impact statement: Greater ecoregion-protection targets for post-2020 biodiversity frameworks warrant discussion. This article is protected by copyright. All rights reserved.

中文翻译：

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评估和扩展欧盟的保护区网络以实现 2020 年后潜在的覆盖目标

《生物多样性公约》（CBD）的战略计划将于 2020 年到期，但生物多样性的丧失仍在继续。科学家们呼吁在下一个协议中制定更雄心勃勃的目标。例如，自然需求减半运动倡导保护地球的一半以解决生物多样性危机，这已转化为保护每个生态区的 50%。我们评估了 CBD 签署国之一欧盟 (EU) 境内生态区的当前保护水平。我们还探讨了扩大 Natura 2000 网络的可能性，以在欧盟成员国的保护区 (PA) 网络中实施 30% 或 50% 的生态区域覆盖率。根据最新的土地利用数据，我们检查了生态区是否有足够的自然面积来达到如此高的覆盖率目标。我们使用空间显式混合整数规划模型来估计基于 3 种情景的 PA 网络的最低​​成本扩展，这些情景分别强调总保护成本、生态系统的生态代表或强调成员国之间的负担均等。为了实现 30% 和 50% 的生态区覆盖，欧盟需要分别将其陆地面积的 6.6% 和 24.2% 添加到其 PA 网络中。对于所有 3 种情景，欧盟需要在半天然森林和其他半或自然生态系统中指定最推荐的新 PA。由于 15 个生态区没有足够的自然面积来实现生态区覆盖目标，一些成员国还需要在生产性土地上建立新的保护区，将最大份额分配给耕地。30% 的生态区覆盖率通过保护所有生态区中剩余的自然区域来实现，除了三个生态区，其中还需要包括生产用地。我们的结果支持对 2020 年后生物多样性框架的更高生态区保护目标的讨论。文章影响声明：2020 年后生物多样性框架的更大生态区保护目标值得讨论。本文受版权保护。版权所有。