UVM Theses and Dissertations
Format:
Print
Author:
Kaproth, Matthew August
Dept./Program:
Plant Biology
Year:
2013
Degree:
PhD
Abstract:
Phenotypic or life-history differences between populations of a species can contribute to variations in fitness and population success. While much research has been focused on the traits of species that lead to invasive success, investigations of the variation within a species may be required, to elucidate the mechanisms driving success across a species range. In the following chapters I present a general literature review covering broad topics of trait variation across .a species range, plant feedbacks and competition. Following this, I present three research papers formatted for publication in peer-reviewed journals. Each study can be used to inform researchers and land managers on how to predict species success and may be useful for species management.
Chapter 2 presents "Leaf litter variation influences invasion dynamics in the invasive wetland grass," which is in review at Biological Invasions. This paper presents that dilution of foliar N present in an invasive grass are tied to stronger performance with high plant litter deposition. Though increased litter decreases survivorship and spring time emergence, invasive high C:N Phalaris arundinacea genotypes are generally stimulated by high litter. The study demonstrates that the components necessary for a positive feedback mechanism are present in the species non-native range, which could explain its success.
Chapter 3 presents "Variation in explosive seed dispersal: Comparing introduced populations to their native counterparts grown under competition," and is formatted for submission to Functional Ecology. This paper presents how fecundity and morphology traits contribute to seed dispersal, how dispersal varies between species ranges, and how dispersal varies between populations in response to competition. Overall, fecundity contributes the most to long distance dispersal (LDD) when plants are grown in the absence of competition; however fecundity is highly sensitive to competition. Differences in the sensitivity to competition were present between ranges: In the native range, LDD was greatly reduced with competition; in the introduced range (USA), LDD was insensitive to competition (a violation of metapopulation models).
Chapter 4 presents "Maternal effects of plant competition: Comparing introduced populations to their native counterparts," and is formatted for journal submission. This paper presents how early life-history traits vary across a weedy species range and how these traits are modified by maternal effects. Using a common garden of seeds harvested from mothers grown under a range of intraspecific competition, we observed varying responses within a species. Both the direction and strength of response vary by population and may be explained by differences in genetic variation, introduction history or adaptive provisioning of offspring when mothers grew under increased competition.
The research presented on the weedy species Cardamine hirsuta in Chapter 3, Chapter 4 and unpublished field studies could be used to parameterize population growth models. Differences between population performances would yield insight to the importance of specific traits and life-history stages over a species range. Additionally, Principal Component Analyses (PCAs) could be utilized to determine correlations of traits by populations and provide insight of trait trade-offs of weedy or invasive species.
Chapter 2 presents "Leaf litter variation influences invasion dynamics in the invasive wetland grass," which is in review at Biological Invasions. This paper presents that dilution of foliar N present in an invasive grass are tied to stronger performance with high plant litter deposition. Though increased litter decreases survivorship and spring time emergence, invasive high C:N Phalaris arundinacea genotypes are generally stimulated by high litter. The study demonstrates that the components necessary for a positive feedback mechanism are present in the species non-native range, which could explain its success.
Chapter 3 presents "Variation in explosive seed dispersal: Comparing introduced populations to their native counterparts grown under competition," and is formatted for submission to Functional Ecology. This paper presents how fecundity and morphology traits contribute to seed dispersal, how dispersal varies between species ranges, and how dispersal varies between populations in response to competition. Overall, fecundity contributes the most to long distance dispersal (LDD) when plants are grown in the absence of competition; however fecundity is highly sensitive to competition. Differences in the sensitivity to competition were present between ranges: In the native range, LDD was greatly reduced with competition; in the introduced range (USA), LDD was insensitive to competition (a violation of metapopulation models).
Chapter 4 presents "Maternal effects of plant competition: Comparing introduced populations to their native counterparts," and is formatted for journal submission. This paper presents how early life-history traits vary across a weedy species range and how these traits are modified by maternal effects. Using a common garden of seeds harvested from mothers grown under a range of intraspecific competition, we observed varying responses within a species. Both the direction and strength of response vary by population and may be explained by differences in genetic variation, introduction history or adaptive provisioning of offspring when mothers grew under increased competition.
The research presented on the weedy species Cardamine hirsuta in Chapter 3, Chapter 4 and unpublished field studies could be used to parameterize population growth models. Differences between population performances would yield insight to the importance of specific traits and life-history stages over a species range. Additionally, Principal Component Analyses (PCAs) could be utilized to determine correlations of traits by populations and provide insight of trait trade-offs of weedy or invasive species.