Woody encroachment of grasslands: Near-surface thermal implications assessed through the lens of an astronomical event.

Autor: Tanner EP; Caesar Kleberg Wildlife Research Institute Texas A&M University-Kingsville Kingsville TX USA.; Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA., Fuhlendorf SD; Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA., Polo JA; Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA., Peterson JM; Department of Natural Resource Ecology and Management Oklahoma State University Stillwater OK USA.
Jazyk: angličtina
Zdroj: Ecology and evolution [Ecol Evol] 2021 Aug 27; Vol. 11 (19), pp. 12886-12901. Date of Electronic Publication: 2021 Aug 27 (Print Publication: 2021).
DOI: 10.1002/ece3.8043
Abstrakt: Temperature has long been understood as a fundamental condition that influences ecological patterns and processes. Heterogeneity in landscapes that is structured by ultimate (climate) and proximate (vegetation, topography, disturbance events, and land use) forces serve to shape thermal patterns across multiple spatio-temporal scales. Thermal landscapes of grasslands are likely shifting as woody encroachment fragments these ecosystems and studies quantifying thermal fragmentation in grassland systems resulting from woody encroachment are lacking. We utilized the August 21st, 2017, solar eclipse to mimic a rapid sunrise/sunset event across a landscape characterized as a grassland to experimentally manipulate levels of solar radiation in the system. We then quantified changes in near-surface temperatures resulting from changes in solar radiation levels during the eclipse. Temperatures were monitored across three grassland pastures in central Oklahoma that were characterized by different densities (low, medium, and high) of Juniperus virginiana to understand the impact of woody encroachment on diurnal temperature patterns and thermal heterogeneity in a grassland's thermal landscape. The largest temperature range across sites that occurred during the eclipse was in the mixed grass vegetation. Similarly, the largest change in thermal heterogeneity occurred in the grassland with the lowest amount of woody encroachment. Thermal heterogeneity was lowest in the highly encroached grassland, which also experienced the lowest overall change in thermal heterogeneity during the eclipse. Time series models suggested that solar radiation was the most influential factor in predicting changes in thermal heterogeneity as opposed to ambient temperature alone. These results suggest that highly encroached grasslands may experience lower diurnal variability of temperatures at the cost of a decrease in the overall thermal heterogeneity of that landscape. It appears that fine-scale spatio-temporal thermal variation is largely driven by solar radiation, which can be influenced by vegetation heterogeneity inherent within a landscape.
Competing Interests: None declared.
(© 2021 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.)
Databáze: MEDLINE
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