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The Missouri Botanical Garden (MBG) plays a pivotal role in plant conservation in the United States through our scientific research on rare and threatened plants of the Midwest. The following is a sampling of ongoing projects:

Restoration of the federally endangered forb Astragalus bibullatus in limestone cedar glades of central Tennessee

Astragalus bibullatus (Fabaceae)
Astragalus bibullatus (Fabaceae) growing on a limestone cedar glade of Middle Tennessee. Approximately 95% of glades in this region
have been destroyed or degraded since
Euro-American settlement.
In collaboration with the U.S. Fish and Wildlife Service, the Tennessee Department of Environment and Conservation, and the National Park Service, MBG’s Center for Conservation and Sustainable Development (CCSD) is participating in a long-term reintroduction program of Pyne’s ground-plum, a highly endangered forb endemic to seven limestone cedar glades in Middle Tennessee. We are conducting greenhouse experiments at CCSD and field studies at multiple cedar glades at the Stones River National Battlefield in Tennessee to understand the ecological factors limiting the distribution and abundance of the species. Our research will identify the appropriate microenvironments for transplanting seeds and seedlings for future restoration efforts.

Population dynamics of the glade endemic Astragalus bibullatus

Dr. Matthew Albrecht
MBG Curator Dr. Matthew Albrecht counting flowers for a demographic study of Pyne’s ground-plum (Astragalus bibullatus)
In collaboration with the Tennessee Department of Environment and Conservation, CCSD is conducting a long-term study on the population dynamics of the federally endangered Pyne’s ground-plum (Astragalus bibullatus). We annually census permanently marked plots and individuals at all known populations of this species to determine the extinction risk of the species in the wild. We are also collecting biotic and abiotic data within plots to understand the ecological drivers of changes in population structure over time. The results from this study will be used to develop management guidelines for ensuring the survival of this species in the wild.

Population genetics of a federally threatened plant, Geocarpon minimum, across a latitudinal gradient

Geocarpon minimum (Caryophyllaceae)
Geocarpon minimum (Caryophyllaceae) growing on a sandstone glade in southwestern Missouri. This diminutive species — plants are rarely larger than
5 cm at maturity — belongs to a monotypic genus.
In collaboration with Dr. Allison Miller and Lauren Broeker (Saint Louis University), we are using molecular genetic methods to answer unresolved questions concerning the evolutionary history and structure of the geographic range of the federally threatened Geocarpon minimum. Populations at the northern part of Geocarpon’s range specialize on sandstone glades, while populations at the southern end of the range specialize on saline prairies that are rich in magnesium and sodium. This study addresses the following questions: 1) How is genetic variation partitioned within and among Geocarpon populations? 2) How genetically diverged are populations across this ecological and latitudinal gradient? 3) Is there evidence of genetic erosion within the species? Data from this study can be used to devise appropriate management strategies aimed at ensuring the survival of this unique species in the wild.

Seed germination dynamics of rare plant species in the Midwestern United States

Claytonia ozarkensis (Portulacaceae)
Claytonia ozarkensis (Portulacaceae) growing on a sandstone cliff face. This newly described species is known from only a handful of sites in Arkansas.
An ongoing project in CCSD’s conservation science lab conducts experiments on seed dormancy and germination in temperate rare plants. The goals of these experiments are: 1) to understand the ways in which environmental factors modulate the phenological patterns of seed germination in the wild, and 2) to develop protocols for ex situ germination of these species for future reintroduction projects. We work specifically with rare plant species for which seed banking serves as a hedge against extinction in the wild. We are currently working on large-scale germination assays with the following species:

Amorpha ouachitensis (Fabaceae)
Astragalus bibullatus (Fabaceae)
Callirhoe bushii (Malvaceae)
Claytonia ozarkensis (Portulacaceae)
Conradina verticillata (Lamiaceae)
Geocarpon minimum (Caryophyllaceae)

Director, CCSD, Missouri Botanical Garden, P.O. Box 299, St. Louis, MO 63166 Phone: (314) 577-0871 © 2014