Trait convergence and trait divergence in herbaceous plant communities: Mechanisms and consequences
Trait convergence and trait divergence in herbaceous plant communities: Mechanisms and consequences
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DOI：
10.1111/j.1654-1103.2006.tb02444.x
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发表时间：
2006-04-01
影响因子：
2.8
通讯作者：
Grime, J. Philip
中科院分区：
文献类型：
--
作者：
Grime, J. Philip
在集约农业的景观中，土壤肥力和植被干扰都能够强烈、均匀和同时地影响草本植物覆盖，两者都倾向于对组成物种的特征施加一致性。在更自然和更古老的草原上，生产力和干扰都发生了更大的时空变化，这两个因素都与草本植物群落物种丰富度的维持有关。然而，经验数据表明，干扰是局部尺度上性状分化和物种共存的更有力的驱动因素。这可能是因为当竞争强度因植被受损而减少时，建立、生长或繁殖机会的巨大多样性。与局部干扰的多样化影响相比，与生产力相关的植物性状(生长速度、叶片寿命、叶片化学、叶片韧性、分解速率)在局部尺度上似乎变化较小。生产力和干扰过滤器的影响的这种差异源于群落内生产力的相对稳定性，以及干扰事件在机构和空间和时间尺度上表现出的多样性。此外，对干扰的进化反应涉及物候和再生性状的微小适应性变化，而且更有可能作为微进化步骤发生，而不是与利用生产性和非生产性生境的能力相关的核心生理性状的变化。在群落的组装过程中，以及在随后的生命周期中，具有多样化和趋同效应的过滤器可能同时作用于从当地物种库中招募新成员，并对共存物种表现出的特征值的相似性产生相反的影响。此外，由于生产力与融合过滤器的频繁关联，根据这两个过滤器对生态系统功能的影响，预测了额外的差异。生产力过滤器所选择的性状的收敛将对植物群落和生态系统产生影响，而干扰过滤器的发散效应将仅限于植物群落。
In landscapes subject to intensive agriculture, both soil fertility and vegetation disturbance are capable of impacting strongly, evenly and simultaneously on the herbaceous plant cover and each tends to impose uniformity on the traits of constituent species. In more natural and ancient grasslands greater spatial and temporal variation in both productivity and disturbance occurs and both factors have been implicated in the maintenance of species-richness in herbaceous communities. However, empirical data suggest that disturbance is the more potent driver of trait differentiation and species co-existence at a local scale. This may arise from the great diversity in opportunities for establishment, growth or reproduction that arise when the intensity of competition is reduced by damage to the vegetation.In contrast to the diversifying effects of local disturbances, productivity-related plant traits (growth rate, leaf longevity, leaf chemistry, leaf toughness, decomposition rate) appear to be less variable on a local scale. This difference in the effects of the productivity and disturbance filters arises from the relative constancy of productivity within the community and the diversity in agency and in spatial and temporal scales exhibited by disturbance events. Also, evolutionary responses to disturbances involve minor adaptive shifts in phenological and regenerative traits and are more likely to occur as micro-evolutionary steps than the shifts in linked traits in the core physiology associated with the capacity to exploit productive and unproductive habitats.During the assembly of a community and over its subsequent lifespan filters with diversifying and convergent effects may operate simultaneously on recruitment from the local species pool and impose contrasted effects on the similarity of the trait values exhibited by co-existing species. Moreover, as a consequence of the frequent association of productivity with the convergence filter, an additional difference is predicted in terms of the effects of the two filters on ecosystem functioning. Convergence in traits selected by the productivity filter will exert effects on both the plant community and the ecosystem while divergent effects of the disturbance filter will be restricted to the plant community.