Abstract The decline of farmland and grassland biodiversity is one the major conservation concerns nowadays. The European roller is a secondary cavity nester species typically inhabiting grasslands and farmlands. It has suffered large declines both in size and range of the population since the 1960s, but this negative trend has been reversed in several countries by applying direct conservation actions. As part of this study we aimed to evaluate the current habitat suitability of the historical breeding area of the species within Hungary, to promote the recolonization and the enlargement of the breeding range in the Carpathian Basin, and to evaluate the potential significance of the Natura 2000 network in this process. We applied species distribution modelling (SDM) based on nest-box occupancy data to map potential areas for nest-box supplementation. Grasslands, broad-leaved forests and agricultural sites with significant areas of natural vegetation were found to be the most important predictors. The majority (71%) of the predicted area has no occupied nest-boxes. A significantly larger proportion of grid cells with archive data still preserve suitable land cover composition for rollers, than cells where former breeding was not confirmed, and only a small proportion of former breeding area has become completely unsuitable for the species. Our results indicate large overlaps between the Natura 2000 network and the predicted area, of which 28.3% overlaps with Special Protection Area (SPA) sites and 23.8% with Special Area of Conservation (SAC/SCI) sites. Our study highlights the importance of promoting the recolonization of the European roller in the Transdanubian region of Hungary and provides a useful tool for direct conservation planning for the species. Our results also suggest that a coordinated network of protected areas such as Natura 2000 can potentially serve as core areas in the recolonization processes.

中文翻译：

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喀尔巴阡盆地欧洲罗拉繁殖范围的潜在扩大

摘要 农田和草地生物多样性的减少是当今主要的保护问题之一。欧洲滚轮是一种次要窝巢物种，通常栖息在草原和农田中。自 1960 年代以来，它的种群规模和范围均大幅下降，但在一些国家，通过采取直接保护行动，这种负面趋势已得到扭转。作为这项研究的一部分，我们旨在评估该物种在匈牙利历史繁殖区的当前栖息地适宜性，促进喀尔巴阡盆地的重新殖民和繁殖范围的扩大，并评估 Natura 2000 的潜在意义这个过程中的网络。我们应用基于巢箱占用数据的物种分布模型 (SDM) 来绘制巢箱补充的潜在区域。草原、阔叶林和拥有大量自然植被的农业用地被发现是最重要的预测因子。预测区域的大部分 (71%) 没有被占用的巢箱。与未确认以前繁殖的单元格相比，具有存档数据的网格单元仍然保留了适合滚轮的合适土地覆盖组成的比例要大得多，并且只有一小部分以前的繁殖区域变得完全不适合该物种。我们的结果表明，Natura 2000 网络与预测区域之间存在大量重叠，其中 28.3% 与特别保护区 (SPA) 站点重叠，23.8% 与特殊保护区 (SAC/SCI) 站点重叠。我们的研究强调了促进欧洲滚子在匈牙利外多瑙河地区重新殖民的重要性，并为该物种的直接保护规划提供了一个有用的工具。我们的结果还表明，Natura 2000 等保护区的协调网络有可能成为重新殖民过程的核心区域。