Date of Completion


Embargo Period



Pamela K. Diggle, Cynthia S. Jones, Donald Les

Field of Study

Ecology and Evolutionary Biology


Master of Science

Open Access

Open Access


The boreal forest is experiencing climate change at twice the rate of other regions. Although changes in flowering phenology are a known consequence of warming temperatures, much is unknown about the effects of temperature anomalies on floral development. Boreal angiosperms preform flowers a year or more in advance and are consequently subject to varied environmental conditions across that time. My thesis examines the effects of temperature on floral development in order to understand how boreal taxa will respond to climate change.

Collection of Vaccinium vitis-idaeafrom natural populations in Fairbanks, Alaska was carried out over the growing seasons of 2017 and 2018 in sites chosen for different temperature regimes. A standardized numerical index of development was created for use in subsequent statistical analyses. Contrary to expectations, linear models and hierarchical ANOVA demonstrated that temperature differences among sites did not explain variation in developmental stage at any given collection period. Rather, period of year and temperature differences across the growing season were significant determinants of variation in development.

Floral development slowed as it proceeded regardless of environmental conditions, and consistently halted at a specific stage in the first year. This pause in development occurred at whatever period the stage was reached. This convergence on a specific developmental stage prior to dormancy suggests an endogenous control on floral development in this species independent of environmental conditions. Given the broad longitudinal and latitudinal distribution of V. vitis-idaea, this invariant cessation of development prevent overwintering damage or premature flowering in the first year.

Major Advisor

Pamela K. Diggle