Undergraduate Honors Theses

Thesis Defended

Fall 2017

Document Type

Thesis

Type of Thesis

Departmental Honors

Department

Environmental Studies

First Advisor

Daniel Doak

Second Advisor

Nancy Emery

Third Advisor

Dale Miller

Abstract

Along with survival, successful reproduction is one of the key features of individual performance that is necessary for a species to survive, including in the face of environmental alterations. This study examined possible drivers of reproductive success in alpine cushion plant Silene acaulis, and the implications of reproductive patterns for long-term stability of populations in the face of climate change. First, I asked whether the timing of flowering in a long-lived alpine plant species influenced whether flowers successfully produced fruit, and whether that timing was correlated with the plant’s long-term seed production. I found that the timing of flowering did have an effect on long-term fruit set – plants that flowered earlier tended to produce more fruit per unit area overall. Secondly, I asked whether some individuals in the population consistently produce more fruit than others, and if trends in fruit production varied at the population level. I found that some individuals consistently produce more fruit than their neighbors, which suggests that some variation in fruit set within a population is due to individual differences (possibly genetic or microhabitat differences). I examined possible correlations between climate factors and fruit production. I used summer temperatures and precipitation as climate indicators, and found that both were negatively correlated with fruit set. I also found that variation in population fruit set was lower than expected, suggesting that disparate individual responses to environmental variation buffer population fruit set.

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