Vulnerability of Tropical Andean Forest tree species to water limitation and its effect at ecosystem scale

ABSTRACT : The Tropical Andean Montane Forest (TAMF) is a crucial ecosystem for the socio-ecological systems and regional climate of Tropical South America. This biome is projected to face significant threats from climate change, which is expected to increase the incidence of drought stress. These stress conditions will limit tree growth and potentially lead to mortality. To evaluate the functional responses of TAMF species to drought, we designed two experiments involving seedlings and saplings of five representative tree species. The experiments included a control group (consistently irrigated), a protracted drought group, and two groups subjected to 50% and 80% of the initial plant-available water that were also exposed to three successive drought cycles. Throughout the experiments, we measured mortality rates, stem volume changes, and functional traits. Our findings reveal that TAMF species exhibit varying degrees of vulnerability to drought due to their diverse functional response strategies. A gradient of vulnerability was observed among the species, ranging from less vulnerable to more vulnerable: Quercus humboldtii, Clusia sp., Croton magdalenensis, Erythrina edulis, and Meriania nobilis. While short-term droughts lasting a few weeks can trigger mortality in TAMF species, even droughts of lower intensity and frequency significantly limit growth without necessarily causing death. Successive drought cycles, even intercalated with irrigation, resulted in growth deficits and increased mortality, highlighting the sensitivity of certain TAMF species. We also found that TAMF species have different water-use strategies, positioned along a two-dimensional continuum ranging from drought avoidance with fast growth to drought tolerance with slow growth. Furthermore, saplings exhibited higher and faster mortality rates than seedlings in most species, except for M. nobilis, where seedlings died more quickly and at earlier stages than saplings. Our results suggest potential ecosystem-level impacts under further climate change scenarios, such as changes in demography, species composition, forest structure, and ecosystem processes.

• Autores: Cano Arboleda, Laura Victoria
• Tipo de recurso: Doctoral thesis
• Fecha de publicación: 2025
• Institución: Universidad de Antioquia
• Repositorio: Repositorio UdeA
• Idioma: eng
• OAI Identifier: oai:bibliotecadigital.udea.edu.co:10495/44777
• Acceso en línea: https://hdl.handle.net/10495/44777
• Palabra clave: Bosque tropical; Tropical forests; Estrés de sequia; Drought stress; Sequía; Drought; Vulnerabilidad; Vulnerability; Ecología forestal; Forest Ecology; Cambio climático; Climate change; Tropical Andean Forest; Water stress; Climate Change Ecology; http://aims.fao.org/aos/agrovoc/c_1666; http://aims.fao.org/aos/agrovoc/c_24904; http://aims.fao.org/aos/agrovoc/c_24993; http://aims.fao.org/aos/agrovoc/c_2391; http://aims.fao.org/aos/agrovoc/c_306b9cc8; http://aims.fao.org/aos/agrovoc/c_3044
• Rights: embargoedAccess
• License: http://creativecommons.org/licenses/by-nc-sa/2.5/co/