Reproductive ecology of a federally endangered legume, Baptisia arachnifera, and its more widespread congener, B. lanceolata (Fabaceae)
Amy S. Young1, Shu-Mei Chang1 and Rebecca R. Sharitz1,2,*
1Department of Plant Biology, University of Georgia, Athens,
Georgia 30602 USA;
2Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, South
Carolina 29802 USA
Abstract
Comparisons between rare species and their more common congener species
can provide valuable information for conservation. Reproductive traits
have previously been shown to be critical for reproductive success and
persistence of rare species. In this study, we compared floral, seedpod,
and seed traits of two Baptisia species (one endangered and one
common) to assess differences in reproduction between species and among
populations. Because heat can trigger germination in hard-seeded legumes,
we also exposed Baptisia seeds to a range of high temperatures
(60-100°C) and determined seed viability. The rare Baptisia arachnifera
had significantly greater pod damage by insects and produced significantly
fewer, yet heavier, seeds than B. lanceolata. While B. arachnifera
seeds were seldom viable at temperatures above 80°C, approximately
40% of B. lanceolata seeds maintained viability up to 100°C.
Our various seed trait measurements suggest that B. arachnifera
may be a poorer colonizer than the more widespread B. lanceolata.
Additionally, B. arachnifera's reduced tolerance for high temperatures
may have implications for appropriate fire management regimes for this
endangered species.
Key
Words
Baptisia; Fabaceae; heat-stimulated germination; predispersal seed
predation; rare-common comparison; reproductive ecology; southeastern
USA
*Corresponding
author
Email address: sharitz@srel.edu (Rebecca R. Sharitz)
SREL Reprint #3019
Young, A. S., S. -M. Chang and R. R. Sharitz. 2007. Reproductive ecology of a federally endangered legume, Baptisia arachnifera, and its more widespread congener, B. lanceolata (Fabaceae). American Journal of Botanty 94(2): 228-236.
