Reconstruction of Holocene vegetation history in three dimensions at Waun-Fignen-Felen, an upland site in South Wales
Reconstruction of Holocene vegetation history in three dimensions at Waun-Fignen-Felen, an upland site in South Wales
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DOI：
10.1098/rstb.1988.0124
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发表时间：
1988-12
期刊：
影响因子：
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通讯作者：
A. Smith;E. W. Cloutman
中科院分区：
文献类型：
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作者：
A. Smith;E. W. Cloutman
通过花粉分析和放射性碳年代测定法对南威尔士一个小型高地沼泽及其周围的十六个地点进行了调查。大多数地点都有厚厚的（毯状）泥炭，上面覆盖着含有丰富木炭的薄薄的基底层。该地区部分地区的覆盖泥炭下面有一个充满泥浆和芦苇沼泽沉积物的德文纪晚期冰川盆地。结论是，盆地的出口可能被沉积泥炭的发育所堵塞，大约距今 6500 年（尽管年代不详），这些泥炭遍布整个盆地，后来蔓延到其西岸。花粉图分为一系列花粉组合区。区域边界在方法的限制内显得同步。榛树在前泥炭矿土的林地植被中发挥着重要作用。大约距今 6000 年前，这片林地已普遍被石南和覆盖泥炭所取代。然而，在泥炭或泥炭尚未开始积累的地区，一些林地显然仍然存在。桤木似乎是在大约 1997 年在盆地地区建立起来的。距今 7000 年前，并在大约 500-1000 年后传播得更广泛，可能是利用了中石器时代人类造成的环境破坏，该地区发现了中石器时代人类居住的证据。结论是，中石器时代的人类可能在大约 10 世纪的林地中开辟了一小块空地。距今8000年，第一批铁矿沉积物开始积累。石南植被大约在这个时候首次出现，并且有通过燃烧维持的间接证据。一些地区的健康状况一直持续到大约。距今 5500 年，在渗透性更强的土壤上发生了灰化。有人认为，石南下相对不透水的莫尔土壤的积累是开始长草泥炭生长的主要因素。这通常开始于大约。距今5500-5800年，但在某些地区既早（约距今7600年）又晚（约距今4000年）。对主要地点的某些花粉曲线的行为进行了比较，发现具有共同特征的地点属于空间相干的组。因此，得出的结论是，花粉图通常反映相对较小区域内发生的植被变化。重建大约4000年后的植被变化。 8000年前的BP是通过一系列地图绘制出来的。大西洋-亚寒带过渡期（距今约 5000-5500 年）的经典榆树衰退有不同的表现，随后出现了一系列其他三个衰退或最小值，可追溯至距今 5000 年至 5500 年。距今约 4600 年距今 4000 年距今 2850 年（尽管同样存在一些可能的变化）。青铜时代似乎是人类对当地植被造成重大影响的时期，在铁器时代早期发生了一些林地再生，然后又开始了新的清理期，这种清理期一直持续到罗马-英国时代。
Sixteen sites in and around a small upland bog in South Wales were investigated by means of pollen analysis and radiocarbon dating. Most of the sites have ombrogenous (blanket) peat overlying a thin basal mor with abundant charcoal. A Devensian Late-glacial basin filled with muds and reedswamp deposits is shown to underlie the blanket peat in part of the area. It is concluded that the outlet of the basin was probably blocked by the development of ombrogenous peat, perhaps around 6500 years BP (though not closely dated), which spread across the basin and later up its western shore. The pollen diagrams are divided into a series of pollen assemblage zones. The zone boundaries appear synchronous within the limits of the methods. Hazel played an important role in the woodland vegetation of the pre-peat mineral soils. This woodland had generally been replaced by heath and blanket peat by about 6000 years BP. Nevertheless, some woodland apparently persisted locally in areas where peat or mor accumulation had not yet begun. Alder appears to have been established in the basin area by ca . 7000 years BP and to have spread more widely some 500—1000 years later, possibly taking advantage of environmental damage caused by Mesolithic man, evidence of whose occupation is found in the area. It is concluded that Mesolithic man was probably responsible for making a small clearing in the woodland at ca . 8000 years BP when the first mor deposit began to accumulate. Heath vegetation first came into existence at about this time and there is circumstantial evidence of maintenance by burning. Heath conditions lasted in some areas until ca . 5500 years BP and on the more permeable soils podsolization took place. It is argued that the accumulation of relatively impermeable mor soils under heath was a major factor in the initiation of ombrogenous peat growth. This most generally began in the period ca . 5500-5800 years BP though it was both earlier ( ca . 7600 years BP) and later ( ca . 4000 years BP) in some areas. A comparison is made of the behaviour of certain pollen curves at the major sites in which it is found that sites with common features fall into spatially coherent groups. It is concluded, therefore, that the pollen diagrams often reflect vegetational changes taking place in relatively small areas. A reconstruction of the vegetational changes in the 4000 years after ca . 8000 years BP is made by means of a series of maps. The classical elm decline of the Atlantic-Sub-boreal transition ( ca . 5000-5500 years BP) is variably represented and there follows a series of three other declines or minima dated to ca . 4600 years BP, ca . 4000 years BP and ca . 2850 years BP (though again with some possible variability). The Bronze Age appears to have been a time of major human impacts on the local vegetation with some woodland regeneration taking place in the earlier Iron Age before a renewed period of clearance that persisted through Romano-British times.