Heterogeneity of Thermal Extremes: Driven by Disturbance or Inherent in the Landscape
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- 作者：Ryan F. Limb ; Samuel D. Fuhlendorf and Darrel E. Townsend
- 关键词：Soil temperature ; Riparian ; Landscape variability ; Thermal refugia ; Global climate change
- 刊名：Environmental Management
- 出版时间：January, 2009
- 出版年：2009
- 期刊代码：41_0364-152X
- 类别：ear
- 卷：43
- 期：1
- 页码：100-106
- 数据来源：sp
摘要
Ecologists are beginning to recognize the effect of heterogeneity on structure and function in arid and semiarid ecosystems. Additionally, the influences of temperature on ecosystems are widely documented, but landscape temperature patterns and relationships with vegetation are rarely reported in ecological studies. To better understand the importance of temperature patterns to the conservation and restoration of native ecosystems, we designed an experiment to investigate relationships among soil surface temperature, landscape heterogeneity, and grazing intensity. Grazing intensity did influence the vegetation structure and composition. Heavy treatments had the greatest bare ground and the least vertical structure. Ungrazed treatments had the most litter and live grass cover. However, average temperatures among the three grazing treatments were not different and ranged less than 2掳C during midday summer periods. The temperature difference between riparian and upland landscapes within grazing treatments was 21掳C. Landscape position (riparian vs. upland) did have a significant influence on soil surface temperature and produced a variation in temperature 11 times greater than grazing intensities. Thermal heterogeneity did not differ among grazing treatments. Lower soil surface temperatures (associated with riparian areas) may provide a critical thermal refuge for many animals in arid and semiarid ecosystems on hot summer days, when air temperatures can exceed 37掳C. Riparian zones, specifically riparian vegetation, are an important component in ecosystem management.