How fragmented was the British Holocene wildwood? Perspectives on the "Vera" grazing debate from the fossil beetle record
How fragmented was the British Holocene wildwood? Perspectives on the "Vera" grazing debate from the fossil beetle record
复制标题
英国全新世野生木材的破碎程度如何？
DOI：
10.1016/j.quascirev.2009.10.010
复制
发表时间：
2010
影响因子：
4
通讯作者：
Whitehouse N
中科院分区：
文献类型：
--
作者：
Whitehouse N
欧洲全新世“原始森林”的重建和结构一直是学术界争论的焦点。古生态学数据，特别是花粉分析，以准确地反映野生树冠密度的能力也得到了广泛的讨论。化石昆虫，作为植被和景观结构的代理，提供了一个潜在的方法来解决这个问题。本文对36个早、中全新世古生物化石进行了回顾和再分析（公元前9500-2000大卡）来自英国的亚化石甲虫组合，检查树木，开阔地和粪甲虫的百分比值以及树木宿主数据，以深入了解植被结构，放牧动物在驱动这种结构中的作用，并独立地建立不同类型的树木和相关阴影在森林中的重要性。全新世早期的“野生森林”。开放指示甲虫物种在整个审查期间持续存在，尽管它们的重要性有所波动。在全新世早期（公元前9500-6000卡尔），这些指标最初很高，其水平与牧场林地的现代数据没有什么不同。然而，在这一时期的后期和下一个时期，公元前6000-4000大卡，开阔地和牧场指标下降，一般低于以前。除了这种模式，我们看到林地指标的重要性普遍增加，尽管有显着的局部波动。在这些时期，蜣螂的数量大多很低，但也有例外，特别是在中石器时代末期和洪泛平原地区。与化石甲虫相关的宿主数据表明，与较轻的树冠条件相关的树木，如橡树，松树，榛树和桦树，确实是全新世早期树冠的重要组成部分。公元前9500-6000 cal），与目前的花粉文献一致。与更耐荫的树木（如石灰和榆树）相关的甲虫在全新世中期（公元前6000-4000大卡）变得更加频繁，这表明在这个阶段，林地树冠比以前更不开放，尽管开放的地面和牧场地区似乎在一些地方持续存在。农业的开始（公元前4000-2000卡）与林地组成和分类群的显著波动相吻合。这可能是人类影响的结果，尽管在这方面存在重大的区域差异。开阔地的数量也有所增加，特别是动物群中的蜣螂数量，这表明放牧动物的活动与更开阔地区的开发之间存在直接关系。这篇评论最引人注目的方面之一是古生态学数据所暗示的景观的可变性，特别是但不完全是农业的开始：一些较早的地点表明，树木相关物种与开阔地甲虫动物群之间的差异很大，这表明在一些地点，开阔地带具有局部意义，可视为全新世景观的重要特征。在新石器时代开始之前，放牧动物在创造这些开放区域方面的作用显然是最小的。
The reconstruction and structure of the European Holocene “wildwood” has been the focus of considerable academic debate. The ability of palaeoecological data and particularly pollen analysis to accurately reflect the density of wildwood canopy has also been widely discussed. Fossil insects, as a proxy for vegetation and landscape structure, provide a potential approach to address this argument. Here, we present a review and re-analysis of 36 early and mid-Holocene (9500–2000 cal BC) sub-fossil beetle assemblages from Britain, examining percentage values of tree, open ground and dung beetles as well as tree host data to gain an insight into vegetation structure, the role of grazing animals in driving such structure and establish independently the importance of different types of trees and associated shading in the early Holocene “wildwood”. Open indicator beetle species are persistently present over the entire review period, although they fluctuate in importance. During the early Holocene (9500–6000 cal BC), these indicators are initially high, at levels which are not dissimilar to modern data from pasture woodland. However, during the latter stages of this and the next period, 6000–4000 cal BC, open ground and pasture indicators decline and are generally low compared with previously. Alongside this pattern, we see woodland indicators generally increase in importance, although there are significant local fluctuations. Levels of dung beetles are mostly low over these periods, with some exceptions to this pattern, especially towards the end of the Mesolithic and in floodplain areas. Host data associated with the fossil beetles indicate that trees associated with lighter canopy conditions such as oak, pine, hazel and birch are indeed important components of the tree canopy during the earlier Holocene (c. 9500–6000 cal BC), in accordance with much of the current pollen literature. Beetles associated with more shade-tolerant trees (such as lime and elm) become more frequent in the middle Holocene (6000–4000 cal BC) suggesting that at this stage the woodland canopy was less open than previously, although open ground and pasture areas appear to have persisted in some locations. The onset of agriculture (4000–2000 cal BC) coincides with significant fluctuations in woodland composition and taxa. This is presumably as a result of human impact, although here there are significant regional variations. There are also increases in the amounts of open ground represented and especially in the levels of dung beetles present in faunas, suggesting there is a direct relationship between the activities of grazing animals and the development of more open areas. One of the most striking aspects of this review is the variable nature of the landscape suggested by the palaeoecological data, particularly but not exclusively with the onset of agriculture: some earlier sites indicate high variability between levels of tree-associated species on the one hand and the open ground beetle fauna on the other, indicating that in some locations, open areas were of local significance and can be regarded as important features of the Holocene landscape. The role of grazing animals in creating these areas of openness was apparently minimal until the onset of the Neolithic.