Factors influencing vegetation gradients across ancient‐recent woodland borderlines in southern Sweden
Factors influencing vegetation gradients across ancient‐recent woodland borderlines in southern Sweden
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影响瑞典南部古近现代林地边界植被梯度的因素
DOI：
10.2307/3246581
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发表时间：
2000
影响因子：
2.8
通讯作者：
M. Diekmann
中科院分区：
文献类型：
--
作者：
J. Brunet;G. Oheimb;M. Diekmann
.我们研究了12个古老的林地和相邻的次生落叶林地之间的过渡带类型的边界线的农田层植被梯度。研究的目的是确定距离边界的影响物种分布相比，土壤因素和郁闭度。对应分析表明，在所有研究地点，距边界线的距离与第一排序轴密切相关。典范对应分析与变化分区显示，距离边界线是唯一的最重要的因素，在解释植被的变化。结果表明，土壤养分的重要性由大到小的顺序为：距边界距离<土壤反应<土壤氮素<土壤水分<冠层覆盖。然而，土壤变量的总和，估计的加权平均值的埃伦贝格指标值的水分，反应和氮，占多达约。总变异的50-70%由环境变量解释。重要的梯度，在现场层植被是由于典型的林地物种的减少和其他物种的增加，随着距离的增加，从古老的林地。结果表明，林地物种的扩散限制作为一个重要的决定因素次生林演替。然而，随着林龄的增加，物种分布距离的重要性降低，因为大多数林地物种逐渐殖民最近的林地。70年后，CA。50%的林地物种存在于一个网站显示出完整的殖民地内50米从古老的林地边界。
. We studied gradients in field layer vegetation across ecotone-type borderlines between 12 ancient woodlands and adjacent secondary deciduous woodlands on former arable land. The aim of the study was to determine how distance from the borderline influences species distributions as compared with soil factors and degree of canopy closure. Correspondence Analysis showed that distance from the borderline is closely related to the first ordination axis at all study sites. Canonical Correspondence Analysis with variation partitioning revealed that distance from the borderline was the single most important factor in explaining vegetation variation. In general, the results suggest the following order of decreasing importance: Distance from the borderline < Soil reaction < Soil nitrogen < Soil moisture < Canopy cover. However, the sum of soil variables, as estimated by weighted averages of Ellenberg indicator values for moisture, reaction and nitrogen, accounted for as much as ca. 50–70% of the total variation explained by environmental variables. Important gradients in field layer vegetation are due to a decrease in typical woodland species and an increase in other species with increasing distance from the ancient woodland. The results suggest dispersal limitation of woodland species as an important determinant of secondary forest succession. However, the importance of distance to species distributions decreases with increasing stand age as most woodland species gradually colonize the recent woodlands. After 70 yr, ca. 50 % of the woodland species present at a site showed complete colonization within 50 m from the ancient woodland border.