Bakker Elisabeth S, Ritchie Mark E, Olff Han, Milchunas Daniel G, Knops Johannes M H
Ecol Lett. 2006 Jul;9(7):780-8. doi: 10.1111/j.1461-0248.2006.00925.x.
Mammalian herbivores can have pronounced effects on plant diversity but are currently declining in many productive ecosystems through direct extirpation, habitat loss and fragmentation, while being simultaneously introduced as livestock in other, often unproductive, ecosystems that lacked such species during recent evolutionary times. The biodiversity consequences of these changes are still poorly understood. We experimentally separated the effects of primary productivity and herbivores of different body size on plant species richness across a 10-fold productivity gradient using a 7-year field experiment at seven grassland sites in North America and Europe. We show that assemblages including large herbivores increased plant diversity at higher productivity but decreased diversity at low productivity, while small herbivores did not have consistent effects along the productivity gradient. The recognition of these large-scale, cross-site patterns in herbivore effects is important for the development of appropriate biodiversity conservation strategies.
哺乳动物食草动物会对植物多样性产生显著影响，但目前在许多高产生态系统中，由于直接灭绝、栖息地丧失和破碎化，其数量正在减少，与此同时，在其他通常生产力较低的生态系统中，它们又作为家畜被引入，而这些生态系统在近代进化时期缺乏此类物种。这些变化对生物多样性的影响仍知之甚少。我们通过在北美和欧洲的七个草原地点进行的为期7年的田间试验，在10倍的生产力梯度上，实验性地分离了初级生产力和不同体型食草动物对植物物种丰富度的影响。我们发现，包含大型食草动物的组合在较高生产力水平下增加了植物多样性，但在低生产力水平下降低了多样性，而小型食草动物在生产力梯度上没有一致的影响。认识到食草动物影响的这些大规模、跨地点模式，对于制定适当的生物多样性保护策略很重要。
