Department of Ecosystem Research, Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.
Food and Environment (INRAE), UMR CARRTEL, University of Savoie Mont-Blanc, French National Research Institute for Agriculture, Thonon-les-Bains, France.
Glob Chang Biol. 2021 Dec;27(24):6409-6422. doi: 10.1111/gcb.15866. Epub 2021 Sep 19.
Land use and climate change are anticipated to affect phytoplankton of lakes worldwide. The effects will depend on the magnitude of projected land use and climate changes and lake sensitivity to these factors. We used random forests fit with long-term (1971-2016) phytoplankton and cyanobacteria abundance time series, climate observations (1971-2016), and upstream catchment land use (global Clumondo models for the year 2000) data from 14 European and 15 North American lakes basins. We projected future phytoplankton and cyanobacteria abundance in the 29 focal lake basins and 1567 lakes across focal regions based on three land use (sustainability, middle of the road, and regional rivalry) and two climate (RCP 2.6 and 8.5) scenarios to mid-21st century. On average, lakes are expected to have higher phytoplankton and cyanobacteria due to increases in both urban land use and temperature, and decreases in forest habitat. However, the relative importance of land use and climate effects varied substantially among regions and lakes. Accounting for land use and climate changes in a combined way based on extensive data allowed us to identify urbanization as the major driver of phytoplankton development in lakes located in urban areas, and climate as major driver in lakes located in remote areas where past and future land use changes were minimal. For approximately one-third of the studied lakes, both drivers were relatively important. The results of this large scale study suggest the best approaches for mitigating the effects of human activity on lake phytoplankton and cyanobacteria will depend strongly on lake sensitivity to long-term change and the magnitude of projected land use and climate changes at a given location. Our quantitative analyses suggest local management measures should focus on retaining nutrients in urban landscapes to prevent nutrient pollution from exacerbating ongoing changes to lake ecosystems from climate change.
预计土地利用和气候变化将影响全球湖泊的浮游植物。这些影响将取决于预计的土地利用和气候变化的幅度以及湖泊对这些因素的敏感性。我们使用随机森林，结合长期（1971-2016 年）浮游植物和蓝藻丰度时间序列、气候观测（1971-2016 年）以及上游集水区土地利用（2000 年全球 Clumondo 模型）数据，来自 14 个欧洲和 15 个北美湖泊流域。我们根据三种土地利用（可持续性、中庸之道和区域竞争）和两种气候（RCP 2.6 和 8.5）情景，预测了 29 个重点湖泊流域和 1567 个重点湖泊在 21 世纪中叶的浮游植物和蓝藻丰度。平均而言，由于城市土地利用和温度的增加，以及森林栖息地的减少，湖泊中的浮游植物和蓝藻预计会增加。然而，土地利用和气候效应的相对重要性在不同地区和湖泊之间存在很大差异。根据广泛的数据，以综合方式考虑土地利用和气候变化，使我们能够确定城市化是城市地区湖泊浮游植物发展的主要驱动因素，而气候是过去和未来土地利用变化最小的偏远地区湖泊的主要驱动因素。大约三分之一的研究湖泊，这两个驱动因素都相对重要。这项大规模研究的结果表明，减轻人类活动对湖泊浮游植物和蓝藻影响的最佳方法将强烈取决于湖泊对长期变化的敏感性以及在特定地点预测的土地利用和气候变化的幅度。我们的定量分析表明，地方管理措施应侧重于保留城市景观中的养分，以防止养分污染加剧气候变化对湖泊生态系统的持续变化。
