Abstract
Aim: Tolerance of species to extreme temperatures largely determines their distribution and vulnerability to climate change. We examined thermal tolerance in tropical and temperate alpine plants, testing the hypotheses that: (a) temperate plants are resistant to more extreme temperatures and have an overall wider thermal tolerance breadth (TTB); (b) TTB in temperate plants is wider than TTB in tropical plants during the entire growing season; (c) resistance to frost and heat varies during the season in temperate plants but not in tropical plants; (d) TTB of a species predicts its latitudinal range. Location: Tropical (Ecuador, Bolivia) and temperate (USA, Austria) mountains. Time period: Four periods of the growing season (2014, 2016–2019). Major taxa: Ninety-six vascular plant species. Methods: We employed the electrolyte leakage method to estimate the temperature resistance, that is, the temperature at which 50% tissue injury (Lt50) occurs in leaves. We used phylogenetic linear mixed-effect models in a Bayesian framework to test for differences between the plant groups. Results: Temperate and tropical plants do not differ in their temperature resistance. The four hypotheses are rejected since: (a) temperate plants do not have significantly wider overall TTB compared to tropical plants, (b) TTB of temperate plants is wider than TTB of tropical plants only at the end of the temperate summer, (c) seasonal acclimation is observed in both plant groups, (d) the latitudinal range of the plants is not related to TTB. Main conclusions: The lack of TTB differences between temperate and tropical alpine plants is consistent with trends observed in ectothermic animals, which suggests a general latitudinal pattern in high-elevation poikilotherm organisms. Limited acclimation capacity to cope with long freezing exposures restricts the occurrence of tropical alpine species to thermally aseasonal environments making them particularly vulnerable to climate change.
| Original language | English |
|---|---|
| Pages (from-to) | 1073-1086 |
| Number of pages | 14 |
| Journal | Global Ecology and Biogeography |
| Volume | 32 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2023 |
Bibliographical note
Publisher Copyright:© 2023 The Authors. Global Ecology and Biogeography published by John Wiley & Sons Ltd.
Funding
The research was funded by the Grant Agency of the Czech Republic (project no. 17‐12420S). Mountain Research Station (University of Colorado), Pontificia Universidad Católica del Ecuador, Universidad Mayor de San Andrés (Herbario Nacional de Bolivia), and Haus de Natur (Salzburg) are thanked for providing research facilities. The work was supported by research permits issued by the Ministerio del Ambiente, Quito, Ecuador (no. 09‐IC‐FLO‐DNB/MAE), Ministerio del Medio Ambiente y Agua, Estado Plurinacional de Bolivia (no. 0481/2018), and directors of the Mountain Research Station, University of Colorado, Boulder, USA and Haus de Natur, Salzburg, Austria. Comments of two anonymous referees are very much acknowledged. The research was funded by the Grant Agency of the Czech Republic (project no. 17-12420S). Mountain Research Station (University of Colorado), Pontificia Universidad Católica del Ecuador, Universidad Mayor de San Andrés (Herbario Nacional de Bolivia), and Haus de Natur (Salzburg) are thanked for providing research facilities. The work was supported by research permits issued by the Ministerio del Ambiente, Quito, Ecuador (no. 09-IC-FLO-DNB/MAE), Ministerio del Medio Ambiente y Agua, Estado Plurinacional de Bolivia (no. 0481/2018), and directors of the Mountain Research Station, University of Colorado, Boulder, USA and Haus de Natur, Salzburg, Austria. Comments of two anonymous referees are very much acknowledged.
Keywords
- Rapoport's rule
- climate seasonality
- ecophysiology
- temperature resistance
- the Andes
- thermal biology
- thermal tolerance breadth
