Denslow Julie Sloan
Department of Botany, University of Wisconsin, 53706, Madison, Wisconsin, USA.
Oecologia. 1980 Jul;46(1):18-21. doi: 10.1007/BF00346960.
I suggest that between-community variations in diversity patterns during succession in plant communities are due to the effects of selection on life history strategies under different disturbance regimes. Natural disturbances to plant communities are simultaneously a source of mortality for some individuals and a source of establishment sites for others. The plant community consists of a mosaic of disturbance patches (gaps) of different environmental conditions. The composition of the mosaic is described by the size-frequency distribution of the gaps and is dependent on the rates and scales of disturbance. The life-history strategies of plant species dependent on some form of disturbance for establishment of propagules should reflect this size-frequency distribution of disturbance patches. An extension of island biogeographic theory to encompass relative habitat area predicts that a community should be most rich in species adapted to growth and establishment in the spatially most common patch types. Changes in species diversity during succession following large scale disturbance reflect the prevalent life history patterns under historically common disturbance regimes. Communities in which the greatest patch area is in large-scale clearings (e.g. following fire) are most diverse in species establishing seedlings in xeric, high light conditions. Species diversity decreases during succession. Communities in which such large patches are rare are characterized by a large number of species that reach the canopy through small gaps and realtively few which regenerate in the large clearings. Diversity increases during succession following a large scale disturbance.Evidence from communities characterized by different disturbance regimes is summarized from the literature. This hypothesis provides an evolutionary mechanism with which to examine the changes in plant community structure during succession. Diversity peaks occurring at "intermediate levels" of disturbance as discussed by Connell and Huston are interpreted in this context.
我认为，植物群落演替过程中群落间多样性模式的差异是由于在不同干扰 regime 下选择对生活史策略的影响。对植物群落的自然干扰同时是一些个体的死亡来源，也是其他个体的定居场所来源。植物群落由不同环境条件的干扰斑块（间隙）镶嵌而成。这种镶嵌的组成由间隙的大小 - 频率分布描述，并取决于干扰的速率和尺度。依赖某种形式的干扰来建立繁殖体的植物物种的生活史策略应反映这种干扰斑块的大小 - 频率分布。将岛屿生物地理学理论扩展到包括相对栖息地面积预测，一个群落应该在适应在空间上最常见斑块类型中生长和定居的物种方面最为丰富。大规模干扰后演替过程中物种多样性的变化反映了历史上常见干扰 regime 下普遍的生活史模式。最大斑块面积处于大规模空地（例如火灾后）的群落，在干旱、高光条件下建立幼苗的物种最为多样。物种多样性在演替过程中降低。这种大斑块稀少的群落的特征是大量物种通过小间隙到达树冠层，而在大空地上再生的物种相对较少。大规模干扰后演替过程中多样性增加。从文献中总结了以不同干扰 regime 为特征的群落的证据。这个假设提供了一种进化机制，用以研究演替过程中植物群落结构的变化。在这种背景下解释了Connell 和 Huston 所讨论的在干扰“中间水平”出现的多样性峰值。
