Waller M P
Department of Geography, University of North London, 383, Holloway Road, London N7 ORN, UK.
New Phytol. 1993 Jun;124(2):345-369. doi: 10.1111/j.1469-8137.1993.tb03825.x.
Pollen data, plant macrofossil remains and lithostratigraphy are used to reconstruct Flandrian vegetational history from a coastal site in south-eastern England. The record at this site, Pannel Bridge in East Sussex, extends back to c. 10000 BP and is the most complete so far obtained from this region. The thirteen pollen assemblages zones defined reflect, in part, the complex development of the site. Prior to c. 8500 BP, wetland in the Pannel valley was localized around the site. Between c. 8500 and c. 6000 BP, in response to changes in coastal configuration, such areas underwent expansion and the valley floor was occupied alternately by sedge fen and Alnus carr. A period of stability followed, with Alnus-dominated communities prevailing for c. 2000 yr. From c. 4000 to c. 2200 BP local conditions were more open with Cyperaceae and subsequently Myrica the dominant wetland types. Alnus carr became re-established c. 2200 BP. The vegetational history of adjacent dryland areas is obscured by the changing local conditions and nature of the deposits investigated. The problems of reconstructing past vegetation from coastal peats are explored. Amongst these are the determination of the pollen source area, establishing an environment of origin for many herb types, and distinguishing the processes controlling wetland vegetational change. The discussion focuses on the arrival and expansion of arboreal taxa in the early Flandrian and human activity. Unusually, Alnus is present in the pollen and macrofossil record from c. 10000 BP onwards. In dryland areas, after an initial Pinus, Betula phase, Corylus populations expanded c. 9500 BP, Quercus and Ulmus became woodland components from c. 9100 BP and c. 8400 BP onwards respectively. Pollen values for Tilia increased c. 7000 BP and Fraxinus c. 5900 BP though both of these taxa were probably locally present earlier. Openings in the forest canopy appear to have persisted after the arrival of the deciduous trees, possibly as a consequence of human activity during the mesolithic. There is some palynological evidence for human presence accompanying the elm decline, though substantial clearance did not occur until the decline in Tilia, c. 3700 BP. This, and a subsequent phase of disturbance c. 3200 BP, appear not to have been followed by periods of intense human activity. Woodland regeneration may have occurred c. 2000 BP.
花粉数据、植物宏观化石遗迹和岩石地层学被用于重建英格兰东南部一个沿海地点的弗兰德植被历史。位于东萨塞克斯郡的潘内尔桥这一地点的记录可追溯到约公元前10000年，是该地区目前获得的最完整记录。所定义的13个花粉组合带部分反映了该地点的复杂发展过程。在约公元前8500年之前，潘内尔山谷的湿地局限于该地点周围。在约公元前8500年至约公元前6000年之间，由于海岸形态的变化，这些区域经历了扩张，谷底交替被莎草草甸和桤木林占据。随后是一段稳定期，以桤木为主的群落盛行约2000年。从约公元前4000年到约公元前2200年，当地环境更为开阔，莎草科植物以及后来的杨梅属植物成为主要的湿地类型。桤木林在约公元前2200年重新建立。相邻旱地的植被历史因当地条件的变化和所研究沉积物的性质而变得模糊不清。探讨了从沿海泥炭重建过去植被的问题。其中包括确定花粉源区、确定许多草本植物类型的起源环境以及区分控制湿地植被变化的过程。讨论集中在弗兰德早期树木类群的到来和扩张以及人类活动。不同寻常的是，从约公元前10000年起，桤木就出现在花粉和宏观化石记录中。在旱地地区，在最初的松树、桦树阶段之后，榛树种群在约公元前9500年扩张，栎树和榆树分别从约公元前9100年和约公元前8400年起成为林地组成部分。椴树的花粉值在约公元前7000年增加，白蜡树的花粉值在约公元前5900年增加，不过这两个类群可能在更早的时候就已在当地存在。落叶树出现后，林冠层的开口似乎一直存在，这可能是中石器时代人类活动的结果。有一些孢粉学证据表明人类在榆树衰退时就已存在，不过直到椴树在约公元前3700年衰退时才出现大规模的砍伐。这一时期以及随后约公元前3200年的干扰阶段之后，似乎并没有紧接着出现人类活动频繁的时期。林地可能在约公元前2000年开始恢复。
