Tree community assembly and biogeochemical processes along an elevational gradient in western Panama

Tropical montane forests (TMF) are unique ecosystems with remarkable contributions to global diversity and C cycle regulation. Understanding factors responsible of TMF dynamics are critical to predicting their plant community response to global change. Elevational and environmental gradients are key elements in our understanding of the effect of climate, edaphic and biotic interactions in plant community assembly and biogeochemical processes. Changes in environmental and biotic conditions are expected to influence tree diversity, floristic composition, nutrient and C cycling. My dissertation evaluates how edaphic factors, climate, and mycorrhizal associations drive tree community assembly, C storage, and biogeochemical processes along environmental gradients. Using a set of twelve plots in a premontane forest established along a natural fertility gradient, I was able to determine that soil fertility, geology, and annual rainfall account for tree species compositional variation in these forests. In a set of nine plots along an elevational gradient, within which forest patches are dominated by either ectomycorrhizal (EM) or arbuscular mycorrhiza (AM) trees, I show that variation in tree species composition is in part explained by the tree species’ mycorrhizal associations, even when controlling for elevation. I further evaluate how climate, edaphic factors and mycorrhizal associations influence biomass and soil C stocks. I report an exceptionally high C stock attributed to the presence of Quercus species at upper elevations and to recent geological history. Finally, I found Quercus-dominated forests are depleted in available N compared to mixed forests, resulting in low N foliar concentrations and low seedling growth rates. This dissertation highlights the importance of incorporating both abiotic and biotic interactions in our understanding of the effects of climate change on forest dynamics. Specifically, I emphasize the role of oak forests on species composition, C stocks and nutrient availability.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Plant Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Prada Cordero, Cecilia M.

Contributors dc:contributor

• Fraterrigo, Jennifer
• Dalling, James W
• Yang, Wendy
• Yannarell, Anthony

• biogeochemical processes
• elevational gradient
• mycorrhizal associations
• nutrient limitation
• tropical montane forests
• Volcan Baru National Park

Statement dc:rights

• Copyright 2021 Cecilia Prada Cordero

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/112960

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/112960