From pristine forests to high-altitude pastures: an ecological approach to prehistoric human impact on vegetation and landscapes in the western Italian Alps

1. This paper addresses the origin and development of the oldest prehistoric pasture in the timberline ecotone known so far in the Alps and its relation to anthropogenic pressure and natural climate change. 2. Paleoecological and geochemical techniques were applied on the Crotte Basse mire stratigraphy (2365 m asl, western Italy) to describe changes in vegetation composition, forest biomass, land use and fertilization between ca. 6400 - 1800 yrs cal BP. 3. Subalpine forests dominated by Pinus cembra occurred at very high-altitude up to ca. 5600 yrs cal BP, when a sharp contraction of woody vegetation took place. This major vegetation shift is matched by increasing charcoal input and markers of pastoral/grazing activities (pollen, dung spores, and forms of phosphorus) in the sediment sequence in this small basin. 4. Major phases of landscape change detected in our multiproxy record chronologically match intervals of cumulative probability density of 14C ages from nearby archaeological...1. 本研究探讨了阿尔卑斯山区迄今已知林线交错带（timberline ecotone）中最古老史前牧场的起源与演化，及其与人为活动压力和自然气候变化的关联。 2. 研究团队对意大利西部海拔2365米的克罗特巴斯（Crotte Basse）泥炭地层开展古生态学（paleoecological）与地球化学（geochemical）分析，以重建约6400至1800校准距今年代（cal BP）间的植被组成、森林生物量、土地利用及施肥状况变化。 3. 在约5600校准距今年代（cal BP）之前，以瑞士五针松（Pinus cembra）为优势种的亚高山森林广泛分布于极高海拔区域，此后木本植被发生急剧收缩。这一显著的植被转变与该小型盆地沉积物序列中炭屑输入量增加，以及畜牧/放牧活动标志物（花粉、粪生孢子及各类磷形态）的增多相吻合。 4. 本研究多代用指标记录中识别出的主要景观变化阶段，在时间序列上与周边考古遗址的碳十四（14C）年代累积概率密度区间相吻合……