Date of Thesis

Spring 2020

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Description

In Pennsylvania Baptisia australis var. australis (L.) R. Br. (Fabaceae) is found along only four waterways: the Allegheny River, Youghiogheny River, Clarion River, and Red Bank Creek. Because of its limited distribution and small number of extant populations, B. australis var. australis is considered state-threatened in Pennsylvania. In addition, the riparian prairie habitat that Pennsylvania Baptisia australis var. australis is restricted to is also in decline and considered vulnerable in the state. Because of conservation concerns for Baptisia australis var. australis in Pennsylvania, gaining insights into the natural history and genetics of the taxon is useful for conservation practitioners. My work carries with it two main objectives: 1) Better understand the ecology and natural history of this state imperiled taxon, and 2) Determine the genetic structure and health of known native populations and apply that information to understanding riparian gene flow, as well as establishing conservation units. Field surveys and herbarium collections were used to examine the natural history of the taxon, particularly to investigate and document granivory in Pennsylvania Baptisia australis var. australis. Using collected data it was determined that in a model of best fit, number of seeds is significantly impacted by the presence of granivores. We also found that visual surveys in the field can be accurately used to assess the presence of granivores. The second portion of this work utilizes genotyping by sequencing (GBS) to collect genetic data for use in population genetics analyses. My work synthesizes these data to gain insight into the metapopulation dynamics of this riparian system and examine patterns of gene flow. We found that there are three genetic groups of Baptisia australis var. australis in Pennsylvania, with one of these showing internal genetic structure, with four demes present. This finding can be applied to management units for the taxon. Some Pennsylvania populations are becoming increasingly isolated as well as shrinking, making now an ideal time to collect seeds and facilitate gene flow while levels of inbreeding are relatively low. My research will inform the conservation status of Baptisia australis var. australis in Pennsylvania, as well as clarify lingering uncertainties about gene flow in riparian plant populations.


Keywords

population genetics, conservation, riparian, Blue False Indigo, riparian, plant ecology

Access Type

Masters Thesis (Bucknell Access Only)

Degree Type

Master of Science

Major

Biology

First Advisor

Christopher Martine

Second Advisor

Angela McDonnell

Third Advisor

Scott Schuette

Comments

Fourth Advisor

Matthew McTammany

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