Date of Award
2020
Document Type
Thesis
Degree Name
M. S.
Department
Biological Sciences
First Advisor
Patrick H. Martin
Keywords
Conifer, Subalpine, Drought
Abstract
Knowledge of tree species’ ability to tolerate drought is necessary to anticipate future forest dynamics with climate change, especially at the seedling stage given their role in shaping forest structure. We used precipitation reduction shelters to mimic drought for subalpine conifer seedlings (A. lasiocarpa and P. engelmannii) in the Rocky Mountains and compared survivorship and morphological and physiological responses to assess relative degrees of drought tolerance. We detected no significant investment in morphological tolerance traits (e.g. root biomass, leaf:stem area ratio) but substantial reductions in net photosynthesis. While shading partially ameliorated drought effects when precipitation reduction was moderate, complete exclusion caused declines in survivorship in both sun and shade tied to poor carbon balances. We identified a lack of stomatal control as a driver of physiological decline in seedlings suggesting a prioritization of traits that, while useful for early establishment, may portend substantial vulnerability of seedling populations to future drought.
Publication Statement
Copyright is held by the author. User is responsible for all copyright compliance.
Recommended Citation
Goke, Alex, "Subalpine Forest Tree Seedling Response to Drought" (2020). Electronic Theses and Dissertations. 1769.
https://digitalcommons.du.edu/etd/1769
Provenance
Received from ProQuest
Rights holder
Alex Goke
File size
58 p.
Copyright date
2020
File format
application/pdf
Language
en
Discipline
Ecology, Biology, Plant sciences
Included in
Forest Biology Commons, Other Ecology and Evolutionary Biology Commons, Plant Biology Commons