Investigating the ecology and population genetics of rare plants can facilitate greater understanding of broader ecological principles. The perennial wildflower Baptisia australis var. australis (L.) R. Br. (Fabaceae) represents an ideal model for examining gene flow in riparian plant populations. Within Pennsylvania, B. australis var. australis is comprised of two metapopulations along four waterways: the Allegheny River, Youghiogheny River, Clarion River, and Red Bank Creek. Despite the location of these watersheds within the greater Ohio River drainage, there is still considerable distance between the metapopulations. Because of its limited distribution and small number of extant populations, B. 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. Given that B. australis var. australis is a species of conservation concern, I am interested in exploring the potential impacts of habitat loss, insect herbivory, and invasive species. Tools such as aerial imagery, field surveys, and herbarium collections are utilized to investigate these threats. ddRAD sequencing is used for population genetics work.
Results/Conclusions
Preliminary results include the presence of several insect pests not previously reported as threats to Pennsylvania populations, including lepidopteran larvae in fruits. Also noted was a decline in suitable habitat corresponding with human development upstream of historic populations, and presence and establishment of several non-native plants in remaining suitable habitat. The overall study seeks to answer the following research questions 1) What is the status of the remaining wild populations of B. australis in Pennsylvania? 2) What is the genetic structure of those known native populations? and 3) What is the relationship of population sizes to the ecological condition of the plant communities that harbor the species? Through answering these questions, I hope to inform the conservation status of Baptisia australis var. australis in Pennsylvania, as well as clarify lingering uncertainties about gene flow in riparian plant populations. This species is an appropriate model for investigating population structure and gene flow of riparian populations since all Pennsylvania populations are known and restricted to riparian prairies. This project will contribute novel insights relating to metapopulation theory and conservation genetics in riparian plant species, both areas of research requiring greater study.