Do silica-based defences drive plant-herbivore dynamics?

基于二氧化硅的防御是否会驱动植物与食草动物之间的动态变化？

• 批准号: NE/F003994/1
• 负责人: Xavier Lambin
• 金额: $ 36.06万
• 依托单位: University of Aberdeen
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FF003994%2F1
• 关键词: Do; silica; based; defences; drive

Understanding the factors that drive changes in the abundance of animal populations is fundamental to ecology. Many herbivore populations show regular oscillations in abundance, known as cycles, and these are usually thought to be due to matched oscillations in the abundance of predators rather than any changes in the herbivore's food plants. Food quality is not thought to respond to herbivory in a way which could lead to cycles, but we have discovered a novel way in which changes in plant quality could cause cycles in herbivore populations. This mechanism has not been considered before but it could apply to wide range of plant-herbivore systems. Our new idea is called the silica induction hypothesis. Periods of sustained heavy grazing lead to an increase in the levels of silica in grasses, so herbivores subsequently experience reduced availability of nutrients. This reduces their growth and reproductive rate and hence slows down the rate of population growth in the following year. Eventually populations fall to a level where there is only low grazing on the grasses, so the levels of silica in the leaves also fall because less well-defended leaves are produced. Herbivores are once again able to access nutrients in the grasses and their growth and reproduction increase again. We believe this mechanism can operate in many plant-herbivore systems, particularly ones based on grasses and other plants that contain high levels of silica. Silicon is the second most abundant mineral on earth and present in significant amounts in all plants, so the mechanism we propose is of wide relevance and significance. We already have some evidence from laboratory experiments and observations in the field that support our idea. In this project we aim to test this potential mechanism for the first time in large-scale field experiments. Firstly, we will determine the silica levels in grasses in areas where vole populations are high and compare them with those in areas where vole populations are low. If our ideas are correct, silica levels should be declining in areas where vole populations are increasing and vice versa. We will then set up an experiment to measure the rate and magnitude of the increase in silica at different levels of grazing and we will also measure how quickly the levels of silica defences decrease. Then we will test our ideas by moving voles into areas where we have induced high silica levels previously and see how feeding in these areas affects their growth and reproduction. These experiments will assess whether changes in plant defences can cause changes in herbivore abundance and help us develop a better understanding of the interactions between grasses and their herbivores. There are many important grassland systems that support a wide range of herbivores, including both rare species and livestock, so this project will be useful to both conservation and sustainable agriculture.

了解驱动动物种群数量变化的因素是生态学的基础。许多食草动物种群的数量表现出规律性的波动，称为周期，通常认为这是由于捕食者数量的相应波动，而不是食草动物的食物植物的任何变化。人们认为食物质量不会以可能导致循环的方式对草食动物做出反应，但我们发现了一种新的方式，植物质量的变化可能会导致草食动物种群的循环。这种机制以前没有被考虑过，但它可以应用于广泛的植物-草食动物系统。我们的新想法称为二氧化硅诱导假说。持续的重度放牧会导致草中二氧化硅的含量增加，因此食草动物随后会经历营养物质的可用性减少。这降低了它们的生长和繁殖率，从而减缓了来年的人口增长率。最终，种群数量下降到草地上的放牧量很少的水平，因此叶子中的二氧化硅含量也会下降，因为叶子的防御能力较差。食草动物再次能够获取草丛中的营养，它们的生长和繁殖再次增加。我们相信这种机制可以在许多植物-草食动物系统中发挥作用，特别是基于草和其他含有高含量二氧化硅的植物的系统。硅是地球上第二丰富的矿物质，在所有植物中大量存在，因此我们提出的机制具有广泛的相关性和意义。我们已经从实验室实验和现场观察中获得了一些证据来支持我们的想法。在这个项目中，我们的目标是首次在大规模现场实验中测试这种潜在机制。首先，我们将测定田鼠数量较多地区草丛中的二氧化硅含量，并将其与田鼠数量较少地区的草进行比较。如果我们的想法是正确的，那么在田鼠数量增加的地区，硅含量应该会下降，反之亦然。然后，我们将进行一项实验来测量不同放牧水平下二氧化硅增加的速度和幅度，我们还将测量二氧化硅防御水平下降的速度。然后，我们将通过将田鼠转移到我们之前诱导高二氧化硅含量的区域来测试我们的想法，并观察这些区域的进食如何影响它们的生长和繁殖。这些实验将评估植物防御的变化是否会导致食草动物丰度的变化，并帮助我们更好地了解草及其食草动物之间的相互作用。有许多重要的草原系统支持各种食草动物，包括稀有物种和牲畜，因此该项目将有助于保护和可持续农业。

项目成果

Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography.

• DOI: 10.1002/ece3.4204
• 发表时间: 2018-08
• 期刊: Ecology and evolution
• 影响因子: 2.6
• 作者: Ruffino L;Hartley SE;DeGabriel JL;Lambin X
• 通讯作者: Lambin X

Silicon, endophytes and secondary metabolites as grass defenses against mammalian herbivores.

• DOI: 10.3389/fpls.2014.00478
• 发表时间: 2014
• 期刊: Frontiers in plant science
• 影响因子: 5.6
• 作者: Huitu O;Forbes KM;Helander M;Julkunen-Tiitto R;Lambin X;Saikkonen K;Stuart P;Sulkama S;Hartley S
• 通讯作者: Hartley S