IFM Biology, Conservation Ecology Group, Linköping University Linköping, SE-581 83, Sweden.
Ecol Evol. 2014 Nov;4(22):4287-95. doi: 10.1002/ece3.1288. Epub 2014 Oct 24.
Plant species richness in central and northern European seminatural grasslands is often more closely linked to past than present habitat configuration, which is indicative of an extinction debt. In this study, we investigate whether signs of historical grassland management can be found in clear-cuts after at least 80 years as coniferous production forest by comparing floras between clear-cuts with a history as meadow and as forest in the 1870s in Sweden. Study sites were selected using old land-use maps and data on present-day clear-cuts. Species traits reflecting high capacities for dispersal and persistence were used to explain any possible links between the plants and the historical land use. Clear-cuts that were formerly meadow had, on average, 36% higher species richness and 35% higher richness of grassland indicator species, as well as a larger overall seed mass and lower anemochory, compared to clear-cuts with history as forest. We suggest that the plants in former meadows never disappeared after afforestation but survived as remnant populations. Many contemporary forests in Sweden were managed as grasslands in the 1800s. As conservation of remaining grassland fragments will not be enough to reduce the existing extinction debts of the flora, these young forests offer opportunities for grassland restoration at large scales. Our study supports the concept of remnant populations and highlights the importance of considering historical land use for understanding the distribution of grassland plant species in fragmented landscapes, as well as for policy-making and conservation.
中欧和北欧半自然草地中的植物物种丰富度通常与过去的而不是现在的生境配置更为密切相关，这表明存在灭绝债务。在这项研究中，我们通过比较瑞典 19 世纪 70 年代的草地和森林历史时期的采伐迹地的植物区系，调查了至少 80 年的针叶林生产林之后的采伐迹地是否能找到历史草地管理的迹象。研究地点是使用旧的土地利用图和当前采伐迹地的数据选择的。反映高扩散和持久性能力的物种特征被用来解释植物与历史土地利用之间的任何可能联系。与作为森林的采伐迹地相比，曾经是草地的采伐迹地的物种丰富度平均高出 36%，草地指示物种的丰富度高出 35%，总种子质量更大，风播率更低。我们认为，在造林后，曾经的草地中的植物并没有消失，而是作为残余种群存活下来。瑞典的许多当代森林在 19 世纪曾被用作草地管理。由于保护剩余的草地碎片不足以减少植物区系现有的灭绝债务，这些年轻的森林为大规模的草地恢复提供了机会。我们的研究支持残余种群的概念，并强调了考虑历史土地利用对于理解破碎景观中草地植物物种分布的重要性，以及对于决策和保护。
