Changes in the ground flora in Wytham Woods, southern England from 1974 to 1991 - implications for nature conservation
Changes in the ground flora in Wytham Woods, southern England from 1974 to 1991 - implications for nature conservation
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DOI：
10.2307/3236557
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发表时间：
2000-12-01
影响因子：
2.8
通讯作者：
Thomas, RC
中科院分区：
文献类型：
--
作者：
Kirby, KJ;Thomas, RC
地面植物区系(维管束植物2米高，不包括乔木和灌木)是1974年和1991年从163个永久性的10米×10米的地块记录下来的，这些地块排列在横跨英国牛津(牛津)附近的威瑟姆森林的系统网格上。森林占地约320公顷，以落叶为主，但年龄和管理类型各不相同。发现的物种总数(173种、167种)、平均丰富度(16.7、17.2)和不同物种类型(古林地指标、其他林地物种、非林地物种)之间的物种列表细目在1974年和1991年之间没有显著差异，但平均地被量从80%下降到%。古代林地指标作为一个整体，显示出与林中开阔的空地和草地斑块相关的物种在年份之间的变化较小。一些树种在林地中的出现频率有所增加，包括斑叶天南星、树枝短柄草、丛生魔芋和草地早熟禾，而其他树种如海棠、当归和黄花草等则有所下降。覆盆子的平均盖度从35%下降到6%，汞的平均盖度从32%下降到24%。从种植园损失的物种比从半自然林损失的物种多。结果仅基于两次，因此对可能原因的推断必须谨慎。然而，结果与(1)与林分生长相关的变化条件的影响是一致的，尤其是在种植园中，以及(2)鹿的取食/放牧增加。没有发现土壤氮素水平变化对植被产生影响的证据。如果要实现自然保护目标，就应该监测地面植物区系和木本层的变化，以及管理和非管理林分的变化。
The ground flora (vascular plants < 2 m high, excluding trees and shrubs) was recorded in 1974 and 1991 from 163 permanent 10 m x 10 m plots arranged on a systematic grid across Wytham Woods, near Oxford (UK). The Woods cover about 320 ha, are predominantly deciduous, but of varying ages and management types. The total number of species found (173, 167 respectively), the mean richness per plot (16.7, 17.2) and the breakdown of the species list between different species types (ancient woodland indicators, other woodland species, non-woodland species) showed no significant differences between 1974 and 1991, but mean ground cover declined from 80% to 64%. Ancient woodland indicators as a group showed less change between the years than species associated with the open glades and grassland patches in the wood. Some species increased in frequency across the woodland including Arum maculatum, Brachypodium sylvaticum, Deschampsia cespitosa and Poa trivialis; while others such as Ajuga reptans, Angelica sylvestris and Circaea lutetiana declined. Mean cover of Rubus fruticosus per plot declined from 35% to 6% and of Mercurialis perennis from 32 to 24%. More species were lost from plantations than from seminatural stands. The results are based on only two times, so inferences on possible causes must be drawn with caution. However the results are consistent with the effects of (1) the changing conditions associated with stand growth, particularly in the plantations, and (2) an increase in browsing/grazing by deer. No evidence was found for an effect of changing soil nitrogen levels on the vegetation. Changes in the ground flora as well as the woody layers, and in managed as well as unmanaged stands should be monitored, if nature conservation objectives are to be met.