Impacts of plant diversity on biomass production increase through time because of species complementarity
Impacts of plant diversity on biomass production increase through time because of species complementarity
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DOI：
10.1073/pnas.0709069104
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发表时间：
2007-11-13
影响因子：
11.1
通讯作者：
Weis, Jerome J.
中科院分区：
文献类型：
--
作者：
Cardinale, Bradley J.;Wright, Justin P.;Weis, Jerome J.
物种灭绝速度的加快促使越来越多的研究人员操纵各种生物体的丰富度，并研究多样性的这一方面如何影响控制生态系统功能的生态过程。我们总结了 44 项操纵植物丰富度的实验的结果，以研究植物多样性如何影响生物量的产生。我们发现，在 79% 的实验中，物种混合产生的生物量平均比物种单一栽培多 1.7 倍，并且比平均单一栽培的生产力更高。然而，在所有实验中，只有 12% 的多种混养物获得的生物量高于单一最高产物种的生物量。此前，不大于最高产物种的多样性的正净效应被解释为选择效应的证据，当多样性使高产物种被纳入并最终主导混养生物量的机会最大化时，就会发生选择效应。与此相反，我们表明，尽管生产性物种确实有助于多样性效应，但物种互补性等于或超过了这些贡献，其中涉及多个物种的生物过程增加了生物量。重要的是，随着时间的推移，多样性的净效应和混养物种比其生产力最高的物种生产力更高的可能性都会增加，因为随着实验时间的延长，互补性的程度也会增加。我们的结果表明，迄今为止的实验低估了物种灭绝对生态系统生产力的影响。
Accelerating rates of species extinction have prompted a growing number of researchers to manipulate the richness of various groups of organisms and examine how this aspect of diversity impacts ecological processes that control the functioning of ecosystems. We summarize the results of 44 experiments that have manipulated the richness of plants to examine how plant diversity affects the production of biomass. We show that mixtures of species produce an average of 1.7 times more biomass than species monocultures and are more productive than the average monoculture in 79% of all experiments. However, in only 12% of all experiments do diverse polycultures achieve greater biomass than their single most productive species. Previously, a positive net effect of diversity that is no greater than the most productive species has been interpreted as evidence for selection effects, which occur when diversity maximizes the chance that highly productive species will be included in and ultimately dominate the biomass of polycultures. Contrary to this, we show that although productive species do indeed contribute to diversity effects, these contributions are equaled or exceeded by species complementarity, where biomass is augmented by biological processes that involve multiple species. Importantly, both the net effect of diversity and the probability of polycultures being more productive than their most productive species increases through time, because the magnitude of complementarity increases as experiments are run longer. Our results suggest that experiments to date have, if anything, underestimated the impacts of species extinction on the productivity of ecosystems.