Subalpine Forest Tree Seedling Response to Drought

<p>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 (<em>A. lasiocarpa</em> and <em>P. engelmannii</em>) 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.</p>

Name thesis:degree_name

M. S.

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2020

Author dc:creator

• Goke, Alex

Contributors dc:contributor

• Patrick H. Martin, Ph.D.
• Anna Sher, Ph.D.
• Michael Kerwin, Ph.D.

• Conifer
• Subalpine
• Drought
• Ecology and Evolutionary Biology
• Forest Biology
• Life Sciences
• Other Ecology and Evolutionary Biology
• Plant Biology
• Plant Sciences

Statement dc:rights

• <p>Copyright is held by the author. User is responsible for all copyright compliance.</p>

Language dc:language

en

Repository record dc:identifier

https://digitalcommons.du.edu/etd/1769

OAI identifier oai:identifier

oai:digitalcommons.du.edu:etd-2761