Ecology Unit, University of León, Campus de Vegazana S/N, 24071 León, Spain; Finnish Environment Institute, Freshwater Centre, P.O. Box 413, FI-90014 Oulu, Finland.
Finnish Environment Institute, Freshwater Centre, P.O. Box 413, FI-90014 Oulu, Finland.
Sci Total Environ. 2021 Sep 10;786:147491. doi: 10.1016/j.scitotenv.2021.147491. Epub 2021 May 3.
Patterns of species rarity have long fascinated ecologists, yet most of what we know about the natural world stems from studies of common species. A large proportion of freshwater plant species has small range sizes and are therefore considered rare. However, little is known about the mechanisms and geographical distribution of rarity in the aquatic realm and to what extent diversity of rare species in freshwater plants follows their terrestrial counterparts. Here, we present the first in-depth analysis of geographical patterns, potential deterministic ecogeographical factors and projected scenarios of freshwater vascular plant rarity using 50 × 50 km grid cells across Europe (41°N-71°N) and North America (25°N-78°N). Our results suggest that diversity of rare species shows different patterns in relation to latitude on the two continents, and that hotspots of rarity concentrate in a relatively small proportion of the European and North American land surface, especially in mountainous as well as in climatically rare and stable areas. Interestingly, we found no differences among alternative rarity definitions and measures when delineating areas with notably high diversity of rare species. Our findings also indicate that few variables, namely a combination of current climate, Late Quaternary climate-change velocity and human footprint, are able to accurately predict the location of continental centers of rare species diversity. However, these relationships are not geographically homogeneous, and the underlying factors likely act synergistically. Perhaps more importantly, we provide empirical evidence that current centers of rare species diversity are characterized by higher anthropogenic impacts and might shrink disproportionately within this century as the climate changes. Our reported distributional patterns of species rarity align with the known trends in species richness of other freshwater organisms and may help conservation planners make informed decisions mitigating the effects of climate change and other anthropogenic impacts on biodiversity.
物种稀有性模式长期以来一直吸引着生态学家的注意，但我们对自然世界的了解大多来自对常见物种的研究。很大一部分淡水植物物种的分布范围较小，因此被认为是稀有种。然而，我们对水生生物稀有物种的机制和地理分布知之甚少，也不知道淡水植物稀有物种的多样性在多大程度上与其陆地同类相似。在这里，我们使用欧洲（41°N-71°N）和北美的 50×50km 网格细胞（25°N-78°N）首次深入分析了淡水维管束植物稀有性的地理模式、潜在的确定性生态地理因素和预测情景。我们的研究结果表明，稀有物种的多样性与两个大陆的纬度有关，稀有物种的热点集中在欧洲和北美的一小部分陆地表面，特别是在山区以及气候稀有和稳定的地区。有趣的是，当划定稀有物种多样性显著的地区时，我们发现不同的稀有性定义和度量方法之间没有差异。我们的研究结果还表明，很少有变量，即当前气候、晚第四纪气候变化速度和人类足迹的组合，能够准确预测大陆稀有物种多样性中心的位置。然而，这些关系在地理上并不均匀，潜在的因素可能协同作用。也许更重要的是，我们提供了经验证据，表明当前稀有物种多样性中心的特点是受到更高的人为影响，并且在本世纪内可能会不成比例地缩小，因为气候变化。我们报告的物种稀有性分布模式与其他淡水生物物种丰富度的已知趋势一致，这可能有助于保护规划者在应对气候变化和其他人为影响对生物多样性的影响时做出明智的决策。
