Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography.
Population-level manipulations of field vole densities induce subsequent changes in plant quality but no impacts on vole demography.
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DOI：
10.1002/ece3.4204
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发表时间：
2018-08
影响因子：
2.6
通讯作者：
Lambin X
中科院分区：
文献类型：
--
作者：
Ruffino L;Hartley SE;DeGabriel JL;Lambin X
放牧引起的植物质量变化被认为是许多草食动物物种表现出的负延迟密度依赖性，但几乎没有现场证据支持这一假设。我们测试了假设的一个关键前提，即在英格兰北方的一个大规模田间实验中，田鼠放牧压力和草中抗草食动物硅防御诱导之间的相互反馈驱动了观察到的种群周期。我们在英格兰北方Kielder森林的1公顷草地上重复降低田鼠（Microtus agrestis）的种群密度，为期1年。随后，我们测试了过去密度对春季田鼠生活史特征的影响，以及这些影响是否是由田鼠主要越冬食物--草Deschampsia caespitosa中的诱导硅防御驱动的。经过几个月的密度操作，叶硅浓度发散，平均降低22%的网站，田鼠密度已减少，但这种差异并没有持续超过该期间的密度操作。有没有显着的影响，我们的密度操作对田鼠体重，春季人口增长率，或平均日期为次年春季繁殖的开始。这些发现表明，在景观尺度上，田鼠的放牧确实会诱导草中硅防御的增加。然而，在所遇到的田鼠密度下，植物损害的水平似乎低于诱导硅水平变化所需的水平，这些变化足够大且持久，足以影响田鼠的表现，证实了我们先前在实验室研究中观察到的阈值效应。我们的研究结果不支持植物质量假说观察到的田鼠种群周期在北方英格兰，至少在范围内的田鼠密度，现在盛行于此。
Grazing‐induced changes in plant quality have been suggested to drive the negative delayed density dependence exhibited by many herbivore species, but little field evidence exists to support this hypothesis. We tested a key premise of the hypothesis that reciprocal feedback between vole grazing pressure and the induction of anti‐herbivore silicon defenses in grasses drives observed population cycles in a large‐scale field experiment in northern England. We repeatedly reduced population densities of field voles (Microtus agrestis) on replicated 1‐ha grassland plots at Kielder Forest, northern England, over a period of 1 year. Subsequently, we tested for the impact of past density on vole life history traits in spring, and whether these effects were driven by induced silicon defenses in the voles’ major over‐winter food, the grass Deschampsia caespitosa. After several months of density manipulation, leaf silicon concentrations diverged and averaged 22% lower on sites where vole density had been reduced, but this difference did not persist beyond the period of the density manipulations. There were no significant effects of our density manipulations on vole body mass, spring population growth rate, or mean date for the onset of spring reproduction the following year. These findings show that grazing by field voles does induce increased silicon defenses in grasses at a landscape scale. However, at the vole densities encountered, levels of plant damage appear to be below those needed to induce changes in silicon levels large and persistent enough to affect vole performance, confirming the threshold effects we have previously observed in laboratory‐based studies. Our findings do not support the plant quality hypothesis for observed vole population cycles in northern England, at least over the range of vole densities that now prevail here.
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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
DOI：
10.1098/rspb.1995.0186
发表时间：
1995-11-22
影响因子：
4.7
作者：
BJORNSTAD, ON;FALCK, W;STENSETH, NC
通讯作者：
STENSETH, NC
影响因子：
64.8
作者：
Ergon, T;Lambin, X;Stenseth, NC
通讯作者：
Stenseth, NC
影响因子：
4.8
作者：
HANSKI, I;HANSSON, L;HENTTONEN, H
通讯作者：
HENTTONEN, H
DOI：
10.1098/rspb.1998.0462
发表时间：
1998-08-22
影响因子：
4.7
作者：
Lambin, X;Elston, DA;MacKinnon, JL
通讯作者：
MacKinnon, JL