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Abstract Detail


López Castro, Guillermo de Jesús [1], Yepez-Gonzalez, Enrico Arturo [2], Álvarez Yépiz, Juan Carlos [2].

Mechanisms of legume dominance along tropical dry forest succession.

Availability of limiting resources changes along forest successional pathways usually concomitant with shifts in dominant species. These plant species may use different functional strategies to cope with changing limiting resources while avoiding competition. The most limiting resource in tropical dry forests is water but during the rainy season light is less available to some plants due to forest canopy closure, which may restrict their capacity to acquire more efficiently key structural elements such as carbon and nitrogen. In this study, we investigate how functional traits related to the acquisition and use of water, light, carbon and nitrogen may help different species to dominate at varying successional stages in a tropical dry forest. We selected an early, an intermediate and a late successional species (Acacia cochliacantha, Lysiloma divaricatum and L. watsonii, respectively) representative of the tropical dry forest of Sonora, Mexico to study vulnerability to embolism (i.e. PLC50), water potential, quantum yield, maximum net photosynthesis, dark respiration, stomatal conductance, leaf C and N content, and abundance of d13C and d15N in leaf tissues. We found significant differences in dark respiration, maximum photosynthesis, and leaf N content as well as in percentage loss conductivity and water potential across species. Notably, A. cochliacanta showed a lower vulnerability to embolism and superior light saturation point. We also observed that L. watsonii consistently showed greater water stress (i.e. inferred from water potential), higher vulnerability to embolism and lower N content. Meanwhile, L. divaricatum kept intermediate values (i.e. PLC50, water potential and dark respiration) in relation to the other species. Our results suggest a high degree of coordination among the three studied species according to their successional dominance, suggesting the pioneer Acacia cochliacantha presents an exploitative resource strategy, L. divaricatum shows an exploitative but generalist strategy in early and late stages of succession, while L. watsonii most conservative resource-use strategy suggests an adaptation to more advanced successional stages. Our study increases our understanding of the mechanisms that allow different legume tree species to dominate at varying stages of secondary succession, which represents a step forward to a more predictive ecology of tropical dry forests.

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1 - Instituto Tecnológico de Sonora, Natural Resource Sciences Master degree, 5 de Febrero 818 sur, Col. Centro. Obregón, Sonora. México, Obregón, Sonora, 85000, México
2 - Instituto Tecnológico de Sonora, Department of Water Sciences and Environment, 5 de Febrero 818 sur, Col. Centro. Obregón, Sonora. México, Obregón, Sonora, 85000, México

functional traits
Leguminous trees
Light curves
Resource-use efficiency
Tropical dry forest
Water potential.

Presentation Type: Poster
Session: P, Ecophysiology Posters
Location: Arizona Ballroom/Starr Pass
Date: Monday, July 29th, 2019
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PPE005
Abstract ID:517
Candidate for Awards:None

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