Protected areas (PAs) are a key element of global conservation strategies aiming to protect habitats and species from various threats such as non-natives species (NNS) with negative ecological impacts. Yet little is known about the mechanisms by which PAs are colonized by NNS, and more specifically the role of colonizing events from surrounding areas. Here, we compared terrestrial and freshwater non-native plants and animals recorded in Norwegian PAs and in 5-km belts around them, using the database of the Norwegian Biodiversity Information Centre Species Map Service. Our analysis included 1,602 NNS and 671 PAs. We found that NNS were recorded in only 23% of the PAs, despite the fact that 90% of the 5-km belts were colonized by at least one NNS. A Zero-inflated negative binomial regression model showed that the number of NNS in the 5-km belts was a strong explanatory variable of the NNS richness inside PAs. Other significant variables included the surface area of the PA, mean human population density in the PA, main type of habitat and accessibility of PAs. We also observed similarity in the species in and around the PAs, with, on average, two thirds of the NNS present in a specific PA also present in its 5-km belt. Furthermore, NNS were recorded in PAs on average 4.5 years after being recorded in the 0–5 km belts, suggesting a dynamic of rapid colonization from the belts to the PAs. Invasive NNS represented 12% of NNS in the belts but 40% in the PAs. This difference was related to the higher abundance of invasive NNS in the belts. Our results highlight the necessity of expanding the focus of NNS management in PAs beyond their boundaries, in particular to prevent incursions of NNS with high negative ecological impact.

中文翻译：

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保护区周围的非本地物种影响其中的非本地物种群落

保护区 (PA) 是全球保护战略的关键要素，旨在保护栖息地和物种免受各种威胁，例如具有负面生态影响的非本地物种 (NNS)。然而，人们对 NNS 定植 PA 的机制知之甚少，更具体地说，对来自周边地区的定植事件的作用知之甚少。在这里，我们使用挪威生物多样性信息中心物种地图服务的数据库比较了挪威保护区及其周围 5 公里带中记录的陆生和淡水非本地动植物。我们的分析包括 1,602 个 NNS 和 671 个 PA。我们发现只有 23% 的 PA 记录了 NNS，尽管事实上 90% 的 5 公里带被至少一个 NNS 殖民。零膨胀负二项式回归模型表明，5 公里带中 NNS 的数量是 PA 内 NNS 丰富度的强解释变量。其他重要变量包括保护区的表面积、保护区的平均人口密度、主要栖息地类型和保护区的可达性。我们还观察到 PA 内部和周围物种的相似性，平均而言，特定 PA 中三分之二的 NNS 也存在于其 5 公里带中。此外，在 0-5 公里带中记录 NNS 后平均 4.5 年在 PA 中记录到 NNS，表明从带到 PA 的快速定植动态。侵入性 NNS 在腰带中占 NNS 的 12%，但在 PA 中占 40%。这种差异与带中侵入性 NNS 的丰度较高有关。