Heterogeneity of Thermal Extremes: Driven by Disturbance or Inherent in the Landscape |
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Authors: | Ryan F Limb Samuel D Fuhlendorf Darrel E Townsend |
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Institution: | (1) Department of Natural Resource Ecology and Management, Oklahoma State University, 008c Agricultural Hall, Stillwater, OK 74078, USA;(2) Grand River Dam Authority, Vinita, OK 74307, USA |
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Abstract: | 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°C during midday summer periods. The temperature difference between riparian and upland landscapes within grazing
treatments was 21°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°C. Riparian zones,
specifically riparian vegetation, are an important component in ecosystem management. |
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Keywords: | Soil temperature Riparian Landscape variability Thermal refugia Global climate change |
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