芬兰奥卢大学Anu Eskelinen等研究人员发现，光照竞争驱动食草动物和营养物质对植物多样性的影响。该项研究成果于2022年11月2日在线发表在《自然》杂志上。

研究人员表明，通过实验恢复天然草地下层植物的光照，可以减轻因营养丰富或没有哺乳动物食草动物而造成的植物多样性损失。在施肥条件下，增加光照对恢复多样性的最初效果是短暂的，并被食草动物对光照水平的更大影响所抵消，这表明食草动物是控制多样性的一个主要因素，部分是通过光照。这些研究结果提供了直接的实验证据，即在一个自然系统中，对光的竞争是导致哺乳动物食草动物停止后生物多样性丧失的一个关键机制。

研究结果还表明，食草动物的影响可以超过施肥对光照竞争的影响。因此，以维持本地或家养食草动物的放牧为目标的管理措施，可以应用于保护草原生态系统的生物多样性，因为它们可以减轻林下的光照竞争。

据悉，营养物质的富集和食草动物的丧失被认为会导致草原生态系统中植物多样性的丧失，因为它们增加了植物的覆盖率，从而导致了底层光照的减少。对自然系统中光照竞争作用的实证检验是基于间接证据的，在过去的40年中一直是一个争论的话题。

附：英文原文

Title: Light competition drives herbivore and nutrient effects on plant diversity

Author: Eskelinen, Anu, Harpole, W. Stanley, Jessen, Maria-Theresa, Virtanen, Risto, Hautier, Yann

Issue&Volume: 2022-11-02

Abstract: Enrichment of nutrients and loss of herbivores are assumed to cause a loss of plant diversity in grassland ecosystems because they increase plant cover, which leads to a decrease of light in the understory1,2,3. Empirical tests of the role of competition for light in natural systems are based on indirect evidence, and have been a topic of debate for the last 40 years. Here we show that experimentally restoring light to understory plants in a natural grassland mitigates the loss of plant diversity that is caused by either nutrient enrichment or the absence of mammalian herbivores. The initial effect of light addition on restoring diversity under fertilization was transitory and outweighed by the greater effect of herbivory on light levels, indicating that herbivory is a major factor that controls diversity, partly through light. Our results provide direct experimental evidence, in a natural system, that competition for light is a key mechanism that contributes to the loss of biodiversity after cessation of mammalian herbivory. Our findings also show that the effects of herbivores can outpace the effects of fertilization on competition for light. Management practices that target maintaining grazing by native or domestic herbivores could therefore have applications in protecting biodiversity in grassland ecosystems, because they alleviate competition for light in the understory.

DOI: 10.1038/s41586-022-05383-9

Source: https://www.nature.com/articles/s41586-022-05383-9