Silvertown Jonathan, McConway Kevin, Gowing David, Dodd Mike, Fay Michael F, Joseph Jeffrey A, Dolphin Konrad
Department of Biological Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, UK.
Proc Biol Sci. 2006 Jan 7;273(1582):39-44. doi: 10.1098/rspb.2005.3288.
A significant proportion of the global diversity of flowering plants has evolved in recent geological time, probably through adaptive radiation into new niches. However, rapid evolution is at odds with recent research which has suggested that plant ecological traits, including the beta- (or habitat) niche, evolve only slowly. We have quantified traits that determine within-habitat alpha diversity (alpha niches) in two communities in which species segregate on hydrological gradients. Molecular phylogenetic analysis of these data shows practically no evidence of a correlation between the ecological and evolutionary distances separating species, indicating that hydrological alpha niches are evolutionarily labile. We propose that contrasting patterns of evolutionary conservatism for alpha- and beta-niches is a general phenomenon necessitated by the hierarchical filtering of species during community assembly. This determines that species must have similar beta niches in order to occupy the same habitat, but different alpha niches in order to coexist.
全球很大一部分开花植物的多样性是在最近的地质时期进化而来的，可能是通过适应性辐射进入新的生态位。然而，快速进化与最近的研究结果不一致，后者表明植物的生态特征，包括β（或栖息地）生态位，进化得非常缓慢。我们已经量化了决定两个群落内栖息地α多样性（α生态位）的特征，在这两个群落中，物种沿着水文梯度分布。对这些数据的分子系统发育分析几乎没有显示出分隔物种的生态距离和进化距离之间存在相关性的证据，这表明水文α生态位在进化上是不稳定的。我们提出，α和β生态位进化保守性的对比模式是群落组装过程中物种分层筛选所必需的普遍现象。这决定了物种为了占据相同的栖息地必须具有相似的β生态位，但为了共存则需要具有不同的α生态位。
