Small herbivores with big impacts: Tundra voles ( Microtus oeconomus ) alter post‐fire ecosystem dynamics
Small herbivores with big impacts: Tundra voles ( Microtus oeconomus ) alter post‐fire ecosystem dynamics
复制标题
影响大的小型食草动物：苔原田鼠 (Microtus oeconomus) 改变火灾后生态系统动态
DOI：
10.1002/ecy.3689
复制
发表时间：
2022
期刊：
影响因子：
4.8
通讯作者：
Rowe, Rebecca J.
中科院分区：
文献类型：
--
作者：
Steketee, Jess K.;Rocha, Adrian V.;Gough, Laura;Griffin, Kevin L.;Klupar, Ian;An, Ruby;Williamson, Nicole;Rowe, Rebecca J.
火是一种重要的生态干扰，可以重置生态系统，并引发植物群落组成，生态系统地球化学和初级生产力的变化。由于食草动物依赖初级生产者的食物，植被的变化可能会改变植物与食草动物的相互作用与重要的，但往往未开发的生态系统的反馈。在这里，我们研究了火灾后植物群落组成和结构的变化对栖息地适宜性和啮齿动物食草动物活动的影响，以应对北方阿拉斯加苔原发生的一场大规模、严重且前所未有的火灾。在发生火灾的潮湿酸性苔原上，苔原田鼠（Microtus oeconomus）是主要的食草动物，依靠草丛形成的莎草Eriophorum vaginatum作为食物和筑巢材料。在火灾发生后7 - 12年，与附近未燃烧的苔原相比，被烧毁的苔原田鼠的数量要多10倍。火增加了田鼠的栖息地适宜性，通过增加植物生产力和生物量，食物质量，并通过两个较高的植被和微地形增加覆盖。由于田鼠丰富度的提高，Eriophorummortality造成的田鼠草食性比自然死亡率高两个数量级，并接近直接由火灾造成的死亡率的大小。这些发现表明，火灾后食草动物对Eriophorum压力的增加反过来会破坏禾本科植物的恢复并增强灌木的侵蚀。在其他干扰和施肥实验之后，苔原状态从禾本科植物为主向灌木为主的转变也很明显，这表明随着北极气温上升，更多的可用养分和大规模干扰频率的增加也可能改变植物与动物的相互作用，对植物群落和生态系统产生连锁反应影响功能。
Fire is an important ecological disturbance that can reset ecosystems and initiate changes in plant community composition, ecosystem biogeochemistry, and primary productivity. As herbivores rely on primary producers for food, changes in vegetation may alter plant–herbivore interactions with important—but often unexplored—feedbacks to ecosystems. Here we examined the impact of post‐fire changes in plant community composition and structure on habitat suitability and rodent herbivore activity in response to a large, severe, and unprecedented fire in northern Alaskan tundra. In moist acidic tundra where the fire occurred, tundra voles (Microtus oeconomus) are the dominant herbivore and rely on the tussock forming sedgeEriophorum vaginatumfor both food and nesting material. Tundra voles were 10 times more abundant at the burned site compared with nearby unburned tundra 7‐12 years after the fire. Fire increased the habitat suitability for voles by increasing plant productivity and biomass, food quality, and cover through both taller vegetation and increased microtopography. As a result of elevated vole abundance,Eriophorummortality caused by vole herbivory was two orders of magnitude higher than natural mortality and approached the magnitude of the mortality rate resulting directly from the fire. These findings suggest that post‐fire increases in herbivore pressure onEriophorumcould, in turn, disrupt graminoid recovery and enhance shrub encroachment. Tundra state transitions from graminoid to shrub dominated are also evident following other disturbances and fertilization experiments, suggesting that as Arctic temperatures rise, greater available nutrients and increased frequencies of large‐scale disturbances may also alter plant–animal interactions with cascading impacts on plant communities and ecosystem function.