The Natura 2000 network of protected sites is the pillar of biodiversity conservation in Europe. Although the Natura 2000 network directly addresses birds, these have shown worrying declining trends. It is therefore crucial to assess the potential contribution of Natura 2000 conservation measures. In this paper, we use a replicable method to model bird trends in the period 2000–2015 and the effects of Natura 2000 protection, across land cover classes, on regional abundances and local species richness and diversity. We model bird trends in Veneto, a North-Eastern Italian Region with areas among the richest in bird species in Italy. Bird data were derived from the national breeding bird monitoring scheme. Breeding birds showed declining trends at the regional level, confirming national and continental trends, particularly on agricultural and natural areas. The land cover class, rather than Natura 2000, mostly influenced population trends; however, it was possible to observe slightly higher estimates of species richness and diversity in Natura 2000 sites. Despite the absolute higher estimates of richness and diversity over the investigated period, farmland and woodland bird species had steeper declining trends inside Natura 2000 than outside, matching the values of the areas outside the network at the end of the survey period. We conclude that the Natura 2000 network capacity to buffer biodiversity loss and act as a species-pool for non-protected areas is decreasing over time, mainly with regards to farmland and woodland birds. Natura 2000 implementation must be improved: conservation objectives and measures, management, and monitoring should be better integrated into existing plans and funding should be made more efficiently available for Natura 2000.

Natura 2000 保护区网络是欧洲生物多样性保护的支柱。尽管 Natura 2000 网络直接针对鸟类，但它们已经显示出令人担忧的下降趋势。因此，评估 Natura 2000 保护措施的潜在贡献至关重要。在本文中，我们使用一种可复制的方法来模拟 2000-2015 年期间的鸟类趋势以及 Natura 2000 保护对跨土地覆盖类别、区域丰度和当地物种丰富度和多样性的影响。我们模拟威尼托的鸟类趋势，意大利东北部地区是意大利鸟类最丰富的地区。鸟类数据来源于国家种鸟监测计划。繁殖鸟类在区域层面呈现下降趋势，证实了国家和大陆的趋势，特别是在农业和自然领域。土地覆盖等级，而不是 Natura 2000，主要影响人口趋势；然而，在 Natura 2000 站点中观察到的物种丰富度和多样性估计值略高。尽管在调查期间对丰富度和多样性的估计绝对更高，但在 Natura 2000 内部，农田和林地鸟类物种的下降趋势比外部更陡峭，与调查结束时网络外区域的值相匹配。我们得出的结论是，Natura 2000 网络缓冲生物多样性丧失和作为非保护区物种库的能力随着时间的推移而下降，主要是在农田和林地鸟类方面。必须改进 Natura 2000 的实施：保护目标和措施、管理、