Reproductive ecology of federally endangered Baptisia arachnifera and its more widespread congener Baptisia lanceolata.
Squire, Amy*,1, 2, Sharitz, Rebecca1, 2, 1 University of Georgia, Athens, GA2 Savannah River Ecology Laboratory, Aiken, SC
ABSTRACT- Understanding the natural history of rare plants is crucial to conservation efforts. Insufficient knowledge of species biology has repeatedly been cited as a shortcoming of endangered species' recovery plans. By contrasting life history traits of restricted versus widespread species, rare-common comparisons can provide essential information for rare plant management. This study compares a comprehensive suite of reproductive traits in two Baptisia species. Baptisia arachnifera and B. lanceolata are long-lived perennial legumes from the Coastal Plain region of the southeastern United States. While B. lanceolata occurs in several states, B. arachnifera is restricted to a 16 kilometer area in southern Georgia, which is primarily managed for pine plantations. Few reproductive traits were found to be significantly different at the species level. More specifically, B. arachnifera plants experienced increased pod damage by insects and produced fewer, yet heavier, seeds than B. lanceolata. Reproductive failure and cumulative fitness (mean number of seeds/individual) were found to be dramatically different within populations of B. arachnifera. Results from a heat stimulated germination experiment suggest that B. arachnifera seeds cannot tolerate temperatures over 80°C, whereas 40% of B. lanceolata seeds maintained viability up to 100°C. Based on comparisons with its more widespread congener, B. arachnifera appears to be most vulnerable during later stages of reproduction. Additionally, B. arachnifera's reduced tolerance for high temperatures may have further implications for appropriate prescribed burn regimes for this species.
Key words: Baptisia , rare-common comparison, reproductive ecology, heat-stimulated germination
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