Abstract Detail

Conservation Biology

Rogers, Will [1], Lee, Diana [2], Platero, Derrick [2], Braley, Gentry [3], Sophia, Calles [4], Rochford, Mia [2], Jared, Odell [5], Anderson, Jill [6], Jennifer, Boyd [7], Cruse-Sanders, Jennifer [2].

Reasons for rarity? Using a common garden approach to investigate the response of rare Pityopsis ruthii (Ruth’s golden aster) to potential habitat change.

Pityopsis ruthii (Small) Small (Ruth’s golden aster) is a rare terrestrial herb endemic to the Ocoee and Hiwasee Rivers in Polk County, TN that is protected as an endangered species under the Endangered Species Act. In total, approximately 12,000 individuals occur within 57 discrete occurrences along the Hiwassee River, while nearly 1,000 individuals occur within nine discrete occurrences along the Ocoee River. In each occurrence, P. ruthii is rooted in narrow cracks and crevices of large exposed boulders located between the edges of the river and forest or within the river channel. It has been suggested that P. ruthii is shade intolerant and a poor competitor, and that a lack of natural scouring of its habitat downstream of dams along the Hiwassee and Ocoee Rivers could allow competing vegetation to encroach and impact the light environment in ways that P. ruthii may not be able to tolerate. We used a common garden approach at the State Botanical Garden of Georgia (Athens, GA) to investigate the response of P. ruthii individuals propagated from seed collected from two natural occurrences of this species from each river to light availability throughout two growing seasons. Specifically, we used a fully replicated experiment to compare the growth, reproduction, and physiology of P. ruthii individuals grown in fully sunlit or 70% shaded plots with comparisons between individuals from distinct occurrences and rivers. Propagation success and survival were high for plants in all treatments. Our results suggest that shade significantly and negatively influenced growth and underlying physiology in P. ruthii similarly regardless of river of origin. Although reproductive effort (measured as flowering) was not influenced similarly by light availability, flowering did differ significantly and dramatically between P. ruthii individuals from different rivers as well as from distinct occurrences along the same river. In contrast, local differences in growth and physiological measures were limited and more minimal. From a habitat and river management perspective, our results suggest that reduced light availability associated with encroaching vegetation could negatively impact this species through reduced growth. We suggest that inherent local variability in flowering could be furthered explored as influential to the dynamics of specific occurrences. Management of P. ruthii habitats aimed at reducing competing vegetation while providing for stability of multiple sites will benefit the species. Successful propagation of P. ruthii ex situ provides opportunities for safeguarding this species at multiple conservation locations to reduce the risk of extinction. 

1 - University of Georgia , State Botanical Garden of Georgia, 2450 South Milledge Ave., Athens, GA, 30605, USA
2 - University Of Georgia, State Botanical Garden Of Georgia, 2450 South Milledge Ave., Athens, GA, 30605, United States
3 - University of Tennessee Chattanooga, 615 McCallie Ave., Chattanooga, TN, 37403, United States
4 - University of Tennessee Chattanooga, 615 McCallie Ave., Chattanooga, TN, 37403, USA
5 - University of Tennessee Chattanooga, Biology, Geology and Environmental Science, 615 McCallie Ave., Chattanooga, TN, 37403, United States
6 - University of Georgia, Department of Genetics, 120 Green Street, Athens, GA, 30602, USA
7 - University Of Tennessee At Chattanooga, Dept 2653, 615 McCallie Avenue, Chattanooga, TN, 37403, United States

life history.

Presentation Type: Poster
Session: P, Conservation Biology Posters
Location: Virtual/Virtual
Date: Monday, July 27th, 2020
Time: 5:00 PM Time and date to be determined
Number: PCB010
Abstract ID:637
Candidate for Awards:None

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