Interactive controls of herbivory and fluvial dynamics on landscape vegetation patterns on the Tanana River floodplain, interior Alaska
Interactive controls of herbivory and fluvial dynamics on landscape vegetation patterns on the Tanana River floodplain, interior Alaska
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DOI：
10.1111/j.1365-2699.2007.01713.x
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发表时间：
2007-09-01
影响因子：
3.9
通讯作者：
Hanley, Thomas A.
中科院分区：
文献类型：
--
作者：
Butler, Lem G.;Kielland, Knut;Hanley, Thomas A.
目的研究哺乳动物、草食动物和河流动态对阿拉斯加内陆塔纳纳河植被动态和组成的交互影响。地理位置模型参数取自阿拉斯加的Tanana河，位于Fairbanks（北纬64度50.50′，西经147度43.30′）和Manley Hot Springs（北纬65度0.0′，西经150度36.0′）之间。方法利用空间显式景观动态模型（ALFRESCO）模拟1年时间步长的植被变化。该模型运行了250年，复制了100次。结果草甸植被的增加降低了早期演替植被的比例，增加了晚期演替植被的比例。侵蚀和增生对草食具有拮抗作用，增加了早期演替植被的数量，减少了晚期演替植被的数量。然而，草食和侵蚀/增生的相互作用在决定系统响应方面尤其重要，特别是在早期的几种植被类型中。高侵蚀率，再加上低草食性，大大增加了柳树在景观中的比例。然而，当与高草食性植物相结合时，它们大大增加了桤木在景观中的比例。在低草食水平下，桤木丰度在中等侵蚀/增生水平时达到峰值。主要结论：侵蚀/增生和草食都不能产生一致的景观格局，不能独立预测。这些发现强调了生物和非生物干扰在北方洪泛平原生态系统中形成大尺度景观植被模式的相互作用的重要性-传统上认为系统主要由非生物干扰单独驱动。
Aim We examined the interactive effects of mammalian herbivory and fluvial dynamics on vegetation dynamics and composition along the Tanana River in interior Alaska.Location Model parameters were obtained from field studies along the Tanana River, Alaska between Fairbanks (64 degrees 50.50' N, 147 degrees 43.30' W) and Manley Hot Springs (65 degrees 0.0' N, 150 degrees 36.0' W).Methods We used a spatially explicit model of landscape dynamics (ALFRESCO) to simulate vegetation changes on a 1-year time-step. The model was run for 250 years and was replicated 100 times.Results Increases in herbivory decreased the proportion of early successional vegetation and increased the proportion of late successional vegetation on the simulated landscape. Erosion and accretion worked as antagonists to herbivory, increasing the amount of early successional vegetation and decreasing the amount of late successional vegetation. However, the interactive effects of herbivory and erosion/accretion were especially important in determining system response, particularly in early seral vegetation types. High erosion rates, when coupled with low herbivory, greatly increased the proportion of willow on the landscape. When coupled with high herbivory, however, they greatly increased the proportion of alder on the landscape. At low levels of herbivory, alder abundance peaked at intermediate levels of erosion/accretion.Main conclusions Neither erosion/accretion nor herbivory produced consistent landscape patterns that could be predicted independently of the other. These findings underscore the importance of the interactive effects of biotic and abiotic disturbances in shaping large-scale landscape vegetation patterns in boreal floodplain ecosystems - systems traditionally thought to be driven primarily by abiotic disturbance alone.