• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Ecohydrology >Biogeography of woody encroachment: why is mesquite excluded from shallow soils?
【24h】

Biogeography of woody encroachment: why is mesquite excluded from shallow soils?

机译：木本植物侵占的生物地理学：为什么豆科灌木植物不在浅层土壤中？

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

While some studies aim to generalise the attributes of woody encroachers, examining their functional differences across biogeographic regions may also be instructive. Most of Texas is encroached by Prosopis glandulosa, but on the eastern Edwards Plateau, a limestone plateau with thin soils, P. glandulosa is rare and Juniperus ashei is dominant. We hypothesised that P. glandulosa is excluded from sites where bedrock at a depth of 1 m or less restricts the development of taproots, thus rendering this normally deep-rooted species too vulnerable to drought. To test this idea, we monitored the physiological status of the two species on a site where both species were encroaching and the soil was 1·5-2·5 m deep, thus relatively deep for the Edwards Plateau region but not for regions where P. glandulosa dominates. Data were collected across three tree size classes from May to November 2006. Stem water potentials were similar across species and water potentials and photosynthetic rates decreased with tree size. Based on isotopic evidence, the effective rooting depth of P. glandulosa increased with tree size, but not in J. ashei. P. glandulosa had a higher rate of leaf gas exchange overall as expected for a drought-avoider; except for large trees during a summer drought, when species differences in photosynthesis rates diminished and the stomatal conductance for J.ashei exceeded that of P. glandulosa. We speculate that restrictions of soil depth may limit the invasiveness of P. glandulosa in part through negative effects on large trees, which may lower fecundity.
机译：尽管一些研究旨在概括木质入侵者的属性，但研究其在生物地理区域的功能差异也可能具有指导意义。得克萨斯州的大部分地区都受到象鼻轮虫的侵害，但是在东部爱德华兹高原（土壤稀薄的石灰岩高原）上，象鼻鸟（P. glandulosa）是罕见的，而Jun藜（Juniperus ashei）则占主导地位。我们假设P. glandulosa被排除在基岩深度小于1 m的地方限制了主根的发育，因此使这种通常根深蒂固的物种太容易受到干旱的影响。为了验证该想法，我们在两种物种都侵占土壤深度为1·5-2·5 m的站点上监视了两种物种的生理状态，因此对于爱德华兹高原地区而言相对较深，而对于P腺体占主导地位。从2006年5月至2006年11月，在三个树木大小类别中收集了数据。不同树种和树木之间的茎水势相似，水势和光合速率随树木大小而降低。根据同位素证据，P。glandulosa的有效生根深度随树的大小而增加，但在J. ashei中却没有。如对干旱的避免所预期的那样，P。glandulosa的叶片气体交换率总体较高。除了在夏季干旱期间的大树以外，光合作用的物种差异减小，并且阿氏烟草的气孔导度超过了兰氏疟原虫的气孔导度。我们推测土壤深度的限制可能部分地通过对大树的不利影响来限制P. glandulosa的入侵，这可能会降低繁殖力。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号