Andrzejak Martin, Knight Tiffany M, Plos Carolin, Korell Lotte
Ecology and Genetics, University of Oulu, Oulu, Finland.
National Tropical Botanical Garden, Kalāheo, Hawaii, USA.
Ecol Appl. 2025 Jan;35(1):e3063. doi: 10.1002/eap.3063. Epub 2024 Dec 8.
Climate change is one of the largest threats to grassland plant species, which can be modified by land management. Although climate change and land management are expected to separately and interactively influence plant demography, this has been rarely considered in climate change experiments. We used a large-scale experiment in central Germany to quantify the effects of grassland management, climate change, and their joint effect on the demography and population growth rate of 11 plant species all native to this temperate grassland ecosystem. We parameterized integral projection models with five years of demographic data to project population growth rate. We hypothesized that plant populations perform better in the ambient than in the future climate treatment that creates hotter and drier summer conditions. Further, we hypothesized that plant performance interactively responds to climate and land management in a species-specific manner based on the drought, mowing, and grazing tolerances as well as the flowering phenology of each species. Due to extreme drought events, over half of our study species went quasi extinct, which highlights how extreme climate events can influence long-term experimental results. We found no consistent support for our expectation that plants perform better in ambient compared with future climate conditions. However, several species showed interactive responses to the treatments, indicating that optimal management strategies for plant performance are expected to shift with climate change. Changes in population growth rates of these species across treatments were mostly due to changes in plant reproduction. Experiments combined with measuring plant demographic responses provide a way to isolate the effects of different drivers on the long-term persistence of species and to identify the demographic vital rates that are critical to manage in the future. Our study suggests that it will become increasingly difficult to maintain species with preferences for moister soil conditions, and that climate and land use can interactively alter demographic responses of the remaining grassland species.
气候变化是草原植物物种面临的最大威胁之一，而土地管理可以对其加以改变。尽管气候变化和土地管理预计会分别并相互影响植物种群统计学特征，但在气候变化实验中这一点很少被考虑。我们在德国中部进行了一项大规模实验，以量化草原管理、气候变化及其共同作用对11种原产于该温带草原生态系统的植物物种的种群统计学特征和种群增长率的影响。我们用五年的种群统计学数据对积分投影模型进行参数化，以预测种群增长率。我们假设，与创造更炎热干燥夏季条件的未来气候处理相比，植物种群在当前气候条件下表现更好。此外，我们假设，基于每种植物的耐旱性、刈割和放牧耐受性以及开花物候，植物表现会以物种特异性的方式对气候和土地管理产生交互响应。由于极端干旱事件，我们研究的物种中有超过一半几近灭绝，这凸显了极端气候事件对长期实验结果的影响。我们没有找到一致的证据支持我们的预期，即与未来气候条件相比，植物在当前气候条件下表现更好。然而，有几个物种对处理表现出了交互响应，这表明植物表现的最佳管理策略预计会随着气候变化而改变。这些物种在不同处理下种群增长率的变化主要归因于植物繁殖的变化。结合测量植物种群统计学响应的实验提供了一种方法，可分离不同驱动因素对物种长期存续的影响，并确定未来管理中至关重要的种群统计学关键率。我们的研究表明，维持偏好更湿润土壤条件的物种将变得越来越困难，而且气候和土地利用会交互改变剩余草原物种的种群统计学响应。
