Dynamic cloud regimes, incident sunlight, and leaf temperatures in espeletia grandiflora and Chusquea tessellata, two representative species of the Andean Páramo, Colombia

The alpine páramo of Chingaza National Park, Colombia, has a highly variable cloud regime typical of many tropical alpine areas. Yet, little information is available regarding the effects of such dynamic sunlight regimes on alpine temperatures. A close association between changes in incident sunligh...

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Autores:
Tipo de recurso:
Fecha de publicación:
2014
Institución:
Universidad del Rosario
Repositorio:
Repositorio EdocUR - U. Rosario
Idioma:
eng
OAI Identifier:
oai:repository.urosario.edu.co:10336/22911
Acceso en línea:
https://doi.org/10.1657/1938-4246-46.2.371
https://repository.urosario.edu.co/handle/10336/22911
Palabra clave:
Air temperature
Climate change
Cloud cover
Dicotyledon
Ecophysiology
Solar radiation
Tundra
Andes
Chingaza national park
Colombia
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Abierto (Texto Completo)
Description
Summary:The alpine páramo of Chingaza National Park, Colombia, has a highly variable cloud regime typical of many tropical alpine areas. Yet, little information is available regarding the effects of such dynamic sunlight regimes on alpine temperatures. A close association between changes in incident sunlight and corresponding air (Ta) and leaf (Tl) temperatures occurred in two dominant species with strongly contrasting leaf form and whole-plant architecture. Spikes in sunlight incidence of and gt;3000 ?mol m-2 s-1 occurred during cloud cover and corresponded to increases in Tl of 4-5 °C in a 1-min-interval in both species. Although Tl was predominately above Ta, during the day, depressions below Ta of over 6 °C occurred during cloudy conditions when photosynthetic photon flux density (PFDs) was and lt;400 ?mol m-2 s-1. The greatest frequency (69%) of changes in incident sunlight (PFDs; over 2-min intervals) was less than 100 ?mol m-2 s-1, although changes and gt;1000 ?mol m-2 s-1 occurred for 2.4% of the day, including a maximum change of 1512 ?mol m-2 s-1. These data may be valuable for predicting the ecophysiological impact of climate warming and associated changes in future cloud regimes experienced by tropical alpine species.