Department of Biological, Geological and Environmental Sciences, University of Bologna, Via Irnerio 42, 40126, Bologna, Italy.
Department of Life, Health and Environmental Sciences, University of L'Aquila, via Vetoio, Coppito, 67100, L'Aquila, Italy.
Sci Rep. 2017 Jul 14;7(1):5415. doi: 10.1038/s41598-017-05114-5.
Although islands are model systems for investigating assembly of biological communities, long-term changes in archipelago communities are not well understood because of the lack of reliable data. By using a vast amount of floristic data we assembled a dataset of the plant species occurring on 16 islands of the Tuscan Archipelago, Italy, across two periods, 1830-1950 and 1951-2015. We collected 10,892 occurrence records for 1,831 species. We found major changes in the island plant assemblages between the two periods, with native flora significantly decreasing (-10.7%) and alien flora doubling (+132.1%) in richness. The species-area relationships demonstrated the scale-dependence of the observed changes for native and alien species. The observed floristic changes were dependent on island area, with smaller islands displaying high variability in richness and compositional changes and larger islands having more stable species assemblages. The richness of species associated with open landscapes, that had been maintained for centuries by traditional practices, markedly reduced while the number of woody species, associated with afforestation processes and invasion by alien woody plants, significantly incresed. These results demonstrate the great power of floristic studies, often available in grey literature, for understanding long-term biotic changes in insular ecosystems.
尽管岛屿是研究生物群落组装的模型系统，但由于缺乏可靠的数据，人们对群岛群落的长期变化了解甚少。通过使用大量的植物区系数据，我们整理了一组意大利托斯卡纳群岛 16 个岛屿上的植物物种数据集，时间跨度为 1830-1950 年和 1951-2015 年。我们共收集了 1831 个物种的 10892 个发生记录。我们发现两个时期之间岛屿植物群发生了重大变化，本地植物群显著减少（-10.7%），外来植物群增加了一倍（+132.1%）。物种-面积关系表明，观察到的本地和外来物种的变化具有尺度依赖性。观察到的植物区系变化取决于岛屿面积，较小的岛屿在丰富度和组成变化方面表现出高度的可变性，而较大的岛屿具有更稳定的物种组合。与几个世纪以来传统实践所维持的开阔景观相关的物种丰富度明显减少，而与造林过程和外来木本植物入侵相关的木本物种数量显著增加。这些结果表明，植物区系研究通常在灰色文献中可用，对于理解岛屿生态系统中的长期生物变化具有巨大的力量。
