Bromus tectorum Response to Fire Varies with Climate Conditions
Bromus tectorum Response to Fire Varies with Climate Conditions
复制标题
雀麦对火灾的反应因气候条件而异
DOI：
10.1007/s10021-014-9771-7
复制
发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
B. Maxwell
中科院分区：
文献类型：
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作者：
Kimberley T. Taylor;T. Brummer;L. Rew;M. Lavin;B. Maxwell
入侵的一年生无芒雀麦通过增加火的频率和大小，在北美西部的鼠尾草生物群的一些地区与火形成正反馈，从而增加了火后雀麦的丰度，并显著改变了生态系统的结构和过程。然而，这种对火的积极反应在整个山艾树草原上并不一致。在这里，我们要问的是，鼠尾草生物群不同的气候条件是否可以解释B.tectorum对火的不同反应。我们发现，在18个B.tectorum对火有积极反应和没有积极反应的地点，气候变量存在显著差异。积极的反应最有可能出现在年气温较高、夏季降水量较少的地区。然后，我们选择了一个气候适中的地点，那里有完好的鼠尾草植被，以评估B.tectorum和Fire之间是否形成了正反馈。该地点最近发生的火灾(1年至15年)的时间序列创造了一个自然重复的实验，以评估B.tectorum和本地植物的丰度。B.tectorum盖度在烧过和未烧过的样地之间没有差别，但在新近发生过火烧的样地中，本地草的盖度较高。因此，我们在研究现场没有发现B.tectorum和FIRE之间存在正反馈的证据。我们的结果表明，正反馈的形成依赖于气候；然而，其他驱动因素，如干扰和原生植物盖度，可能会进一步影响B.tectorum的局部反应。B.tectorum对火的反应对气候的依赖表明，气候变化可能会扩大B.tectorum作为鼠尾草生物群中变革性入侵物种的作用。
The invasive annual grass Bromus tectorum (cheatgrass) forms a positive feedback with fire in some areas of western North America’s sagebrush biome by increasing fire frequency and size, which then increases B. tectorum abundance post-fire and dramatically alters ecosystem structure and processes. However, this positive response to fire is not consistent across the sagebrush steppe. Here, we ask whether different climate conditions across the sagebrush biome can explain B. tectorum’s variable response to fire. We found that climate variables differed significantly between 18 sites where B. tectorum does and does not respond positively to fire. A positive response was most likely in areas with higher annual temperatures and lower summer precipitation. We then chose a climatically intermediate site, with intact sagebrush vegetation, to evaluate whether a positive feedback had formed between B. tectorum and fire. A chronosequence of recent fires (1–15 years) at the site created a natural replicated experiment to assess abundance of B. tectorum and native plants. B. tectorum cover did not differ between burned and unburned plots but native grass cover was higher in recently burned plots. Therefore, we found no evidence for a positive feedback between B. tectorum and fire at the study site. Our results suggest that formation of a positive B. tectorum-fire feedback depends on climate; however, other drivers such as disturbance and native plant cover are likely to further influence local responses of B. tectorum. The dependence of B. tectorum’s response to fire on climate suggests that climate change may expand B. tectorum’s role as a transformative invasive species within the sagebrush biome.