Abstract Though protected areas are recognized as the cornerstone of global conservation efforts, their effectiveness in safeguarding biodiversity is currently debated. In particular, studies evaluating the counterfactual influence of protection status on community metrics derived from field-collected data are still scarce. In this paper, using data from a resurveying study, we assessed the contribution of the European Natura 2000 network to maintaining and/or improving through time habitat quality and functional integrity in Mediterranean coastal dune habitats, which appear among the most threatened ecosystems worldwide. Using multiple regression techniques, we tested the influence of protection status on habitat loss and on 10–15 years changes in the richness and cover of two highly informative plant groups: focal and alien species. Next to a substantial habitat loss, we observed an overall decrease in focal species richness and cover, whereas alien species were stable or slightly increasing, depending on the habitat. Surprisingly, changes in the analyzed metrics did not differ between protected and non-protected sites, thus providing no substantial evidence of the effectiveness of Natura 2000 in conserving and/or improving dune habitats. Taken together, such results suggest negative implications for the whole ecosystem structure and functionality, to be expected regardless of the protection status. This led us to reflect about the general inadequacy in the implementation of actual conservation measures in coastal habitats, discuss potential causes (lack of ad-hoc management plans and targeted conservation measures, scarcity of dedicated funding, bureaucratization), and stress the value of monitoring activities for evaluating conservation outcomes and reformulating current strategies.

中文翻译：

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Natura 2000 网络在保护地中海沿岸沙丘栖息地方面的有效性

摘要 尽管保护区被认为是全球保护工作的基石，但目前对其保护生物多样性的有效性存在争议。特别是，评估保护状态对来自现场收集数据的社区指标的反事实影响的研究仍然很少。在本文中，我们使用来自重新调查研究的数据评估了欧洲自然 2000 网络对维护和/或改善地中海沿岸沙丘栖息地的栖息地质量和功能完整性的贡献，这些栖息地似乎是全球受威胁最严重的生态系统之一。使用多元回归技术，我们测试了保护状态对栖息地丧失的影响以及对两个高度信息植物群（焦点物种和外来物种）的丰富度和覆盖度的 10-15 年变化的影响。除了栖息地大量丧失之外，我们观察到焦点物种丰富度和覆盖率总体下降，而外来物种稳定或略有增加，具体取决于栖息地。令人惊讶的是，受保护和非受保护地点的分析指标变化没有差异，因此没有提供实质性证据证明 Natura 2000 在保护和/或改善沙丘栖息地方面的有效性。总之，这些结果表明对整个生态系统结构和功能的负面影响，无论保护状态如何，都是可以预期的。这促使我们反思沿海栖息地实际保护措施的实施普遍不足，讨论潜在原因（缺乏临时管理计划和有针对性的保护措施，缺乏专门资金，官僚化），