Scottish Oceans Institute, School of Biology, University of St Andrews, St Andrews, UK.
Åbo Akademi University, Environmental and Marine Biology, Turku, Finland.
Glob Chang Biol. 2024 Aug;30(8):e17482. doi: 10.1111/gcb.17482.
Rising global temperatures are often identified as the key driver impacting ecosystems and the services they provide by affecting biodiversity structure and function. A disproportionate amount of our understanding of biodiversity and function is from short-term experimental studies and static values of biodiversity indices, lacking the ability to monitor long-term trends and capture community dynamics. Here, we analyse a biennial dataset spanning 32 years of macroinvertebrate benthic communities and their functional response to increasing temperatures. We monitored changes in species' thermal affinities to examine warming-related shifts by selecting their mid-point global temperature distribution range and linking them to species' traits. We employed a novel weighted metric using Biological Trait Analysis (BTA) to gain better insights into the ecological potential of each species by incorporating species abundance and body size and selecting a subset of traits that represent five ecosystem functions: bioturbation activity, sediment stability, nutrient recycling and higher and lower trophic production. Using biodiversity indices (richness, Simpson's diversity and vulnerability) and functional indices (richness, Rao's Q and redundancy), the community structure showed no significant change over time with a narrow range of variation. However, we show shifts in species composition with warming and increases in the abundance of individuals, which altered ecosystem functioning positively and/or non-linearly. Yet, when higher taxonomic groupings than species were excluded from the analysis, there was only a weak increase in the measured change in community-weighted average thermal affinities, suggesting changes in ecosystem functions over time occur independently of temperature increase-related shifts in community composition. Other environmental factors driving species composition and abundance may be more important in these subtidal macrobenthic communities. This challenges the prevailing emphasis on temperature as the primary driver of ecological response to climate change and emphasises the necessity for a comprehensive understanding of the temporal dynamics of complex systems.
全球气温上升通常被认为是影响生态系统及其提供的服务的关键驱动因素，因为它会影响生物多样性的结构和功能。我们对生物多样性和功能的理解很大程度上来自于短期的实验研究和生物多样性指数的静态值，缺乏监测长期趋势和捕捉群落动态的能力。在这里，我们分析了一个为期 32 年的大型底栖无脊椎动物群落及其对温度升高的功能响应的两年一度数据集。我们监测了物种热亲和度的变化，以通过选择其全球温度分布范围的中点并将其与物种特征联系起来，来研究与变暖相关的物种变化。我们使用了一种新颖的加权度量方法，即生物特征分析（BTA），通过纳入物种丰度和体型，并选择代表五个生态系统功能的特征子集：生物搅动活性、沉积物稳定性、养分循环以及更高和更低的营养级生产，从而更好地了解每个物种的生态潜力。使用生物多样性指数（丰富度、辛普森多样性和脆弱性）和功能指数（丰富度、Rao 的 Q 和冗余），群落结构在时间上没有明显变化，变化范围很窄。然而，我们发现随着温度的升高和个体数量的增加，物种组成发生了变化，这对生态系统功能产生了积极的和/或非线性的影响。然而，当将高于物种的分类群从分析中排除时，测量的群落加权平均热亲和度变化只有微弱的增加，这表明随着时间的推移，生态系统功能的变化独立于与温度升高相关的群落组成变化。其他驱动物种组成和丰度的环境因素在这些潮下大型底栖无脊椎动物群落中可能更为重要。这挑战了将温度作为生态系统对气候变化响应的主要驱动因素的主流观点，并强调了全面了解复杂系统时间动态的必要性。
