Emergence patterns of novelty in European vegetation assemblages over the past 15 000 years

Plant communities are not stable over time and biological novelty is
predicted to emerge due to climate change, the introduction of exotic
species and land-use change. However, the rate at which this novelty may
arise over longer time periods has so far received little attention. We
reconstruct the emergence of novelty in Europe for a set of baseline
conditions over the past 15 000 years to assess past rates of emergence
and investigate underlying causes. The emergence of novelty is baseline
specific and, during the early-Holocene, was mitigated by the rapid spread
of plant taxa. Although novelty generally increases as a function of time,
climate and human-induced landscape changes contributed to a non-linear
post-glacial trajectory of novelty with jumps corresponding to periods of
rapid changes. Emergence of novelty accelerated during the past 1000
years. Historical cultural landscapes experienced a faster novelty
development due to the contribution from anthropogenic land-cover changes.

植物群落并非始终处于稳定状态，而气候变化、外来物种引入以及土地利用变化被预测将催生生物新颖性（biological novelty）。然而，目前学界对该新颖性在更长时间尺度上的产生速率仍关注不足。本研究基于一系列基准情景，重建了过去15000年间欧洲地区的生物新颖性出现过程，以此评估历史上的新颖性产生速率，并探究其背后的驱动因素。生物新颖性的出现具有基准情景依赖性，在早全新世（early-Holocene）时期，植物类群的快速扩散曾抑制了新颖性的产生。尽管新颖性总体上随时间推移而增长，但气候变化与人类主导的景观变化共同造就了冰期后新颖性演化的非线性轨迹，其增速峰值与快速变化时期高度吻合。近1000年来，生物新颖性的产生速率进一步加快。受人为土地覆盖变化的影响，历史人文景观中的新颖性发展速率更快。