Searching to improve connectivity in fragmented landscapes: Road verges as complementary habitats

Abstract Aims: Functional connectivity is crucial for conserving biodiversity and ecosystem services in fragmented landscapes. Linear landscape elements play an important role in providing refuge for plants and pollinators, as well as serving as biological corridors. The aim of this study was to assess the importance of road verges in maintaining the ecological connectivity of plant species assemblages in the Tandilia mountain system. Location: South America. Southern Pampa region of Argentina. Tandilia mountain system. Methods: Using graph theory, landscape connectivity was quantified both at landscape scale and at the patch scale using the probability connectivity index (PCnum), taking into account the dispersal ability of observed species. The contribution of each landscape element to habitat availability and connectivity was evaluated using different fractions of the PCnum metric. Likewise, the influence of connectivity variables in explaining species assemblages grouped by functional categories was investigated using canonical ordination techniques. Results: The inclusion of road verges led to an 81% increase in overall connectivity at a threshold distance of 500 m. Connectivity significantly explained the assemblages of entomophilous plant species for all dispersal distances. Annual species assemblage variation was associated with intra-patch connectivity. Variation in perennial and shrub species assemblages was explained by intra-patch and inter-patch connectivity. Conclusions: Preservation and restoration of these linear landscape elements play a pivotal role in transitioning towards more sustainable agroecosystems. This ecological and practical information may help prioritize plant species and the sites used to restore an essential but neglected ecosystem. This dataset includes: GPS coordinates for sampling sites. Data matrix includes sites x presence-absence of entomophilous plant species for the 54 sampling sites, 20 sierras and 34 rural road verges. The sierras are listed by name, while the road verges are identified by numbers.摘要 研究目标：功能连通性（functional connectivity）对破碎化景观中的生物多样性保护与生态系统服务维持至关重要。线性景观要素可为植物与传粉者提供庇护所，同时充当生物廊道。本研究旨在评估道路路肩（road verges）在维持坦迪亚利亚山脉系统中植物物种组合的生态连通性方面的重要性。 研究区域：南美洲。阿根廷南部潘帕斯草原区域。坦迪亚利亚山脉系统。 研究方法：采用图论（graph theory），基于观测物种的扩散能力，分别在景观尺度与斑块尺度下通过概率连通性指数（PCnum）对景观连通性进行量化。利用概率连通性指数的不同分数形式，评估各景观要素对生境可用性与连通性的贡献。此外，采用典范排序技术（canonical ordination techniques），探究连通性变量对按功能类群划分的物种组合的解释能力。 研究结果：在500米阈值距离下，纳入道路路肩可使整体连通性提升81%。连通性可显著解释所有扩散距离下的虫媒植物（entomophilous plant species）物种组合。一年生植物物种组合的变异与斑块内连通性相关。多年生植物与灌木类物种组合的变异可通过斑块内和斑块间连通性进行解释。 研究结论：保护与修复这类线性景观要素，对构建更可持续的农业生态系统发挥着关键作用。本研究获得的生态学与实践信息，可为优先保护植物物种及修复关键却被忽视的生态系统的选址提供参考。 本数据集包含： 1. 采样点位的GPS坐标。 2. 数据矩阵：为采样点位×虫媒植物物种存在-缺失矩阵，涵盖54个采样点位，其中包含20处丘体与34条乡村道路路肩。丘体以名称标注，道路路肩以编号标识。