1. Does plant ecosystem thermoregulation occur? An extratropical assessment at different spatial and temporal scales.
- Author
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Guo Z, Still CJ, Lee CKF, Ryu Y, Blonder B, Wang J, Bonebrake TC, Hughes A, Li Y, Yeung HCH, Zhang K, Law YK, Lin Z, and Wu J
- Subjects
- Body Temperature Regulation, Temperature, Climate Change, Ecosystem, Plants
- Abstract
To what degree plant ecosystems thermoregulate their canopy temperature (T
c ) is critical to assess ecosystems' metabolisms and resilience with climate change, but remains controversial, with opinions from no to moderate thermoregulation capability. With global datasets of Tc , air temperature (Ta ), and other environmental and biotic variables from FLUXNET and satellites, we tested the 'limited homeothermy' hypothesis (indicated by Tc & Ta regression slope < 1 or Tc < Ta around midday) across global extratropics, including temporal and spatial dimensions. Across daily to weekly and monthly timescales, over 80% of sites/ecosystems have slopes ≥1 or Tc > Ta around midday, rejecting the above hypothesis. For those sites unsupporting the hypothesis, their Tc -Ta difference (ΔT) exhibits considerable seasonality that shows negative, partial correlations with leaf area index, implying a certain degree of thermoregulation capability. Spatially, site-mean ΔT exhibits larger variations than the slope indicator, suggesting ΔT is a more sensitive indicator for detecting thermoregulatory differences across biomes. Furthermore, this large spatial-wide ΔT variation (0-6°C) is primarily explained by environmental variables (38%) and secondarily by biotic factors (15%). These results demonstrate diverse thermoregulation patterns across global extratropics, with most ecosystems negating the 'limited homeothermy' hypothesis, but their thermoregulation still occurs, implying that slope < 1 or Tc < Ta are not necessary conditions for plant thermoregulation., (© 2022 The Authors New Phytologist © 2022 New Phytologist Foundation.)- Published
- 2023
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