Missouri Botanical Garden

Noah Dell, Missouri Botanical Garden, Geoff Call, United States Fish and Wildlife Service, Matthew A. Albrecht, Missouri Botanical Garden

Short’s bladderpod (Physaria globosa) was recently listed as federally endangered due to population decline across its range in Tennessee and Kentucky. However, little is known about the biology of the species and the potential mechanisms underlying range-wide declines. In short-lived mustards, seed dormancy and seed bank persistence can play an important role in regulating population dynamics and response to disturbance. To address the recovery plan objective of enhancing knowledge of Short’s Bladderpod to facilitate the development of scientifically sound management plans, we conducted laboratory experiments and a seed burial study to examine what environmental cues promote dormancy break and whether or not seeds form a persistent seed bank. A majority of seeds are in primary dormancy when dispersed in summer. Germination percentages are generally low, and long cold stratification times are needed to break dormancy. Seeds that were cold stratified at 2°C for 12 weeks and then incubated in a 20/10°C alternating temperature regime achieved the highest average germination percentage (24%). Warm stratification with or without alternating wet/dry cycles did not improve germination percentages over cold stratification treatments. However, constant imbibition in warm temperatures may have promoted viability loss, as germination percentages were lower than seeds kept at warm temperatures with alternating wet/dry cycles. Results from the seed burial study were consistent with those in laboratory experiments and indicate a cold stratification requirement for dormancy-break. Germination of buried seeds was greater in light than darkness and varied seasonally: 0% and 1% in dark and light conditions, respectively, in October following dispersal, 7% and 21% in January, 23% and 36% in March, 9% and 10% in June, and 4% and 8% in October in the year following dispersal. Seeds that afterripened in ambient indoor conditions for up to one year germinated to low (< 2%) percentages, indicating dry storage does not substitute for cold stratification in breaking seed dormancy. The germination niche of P. globosa can be defined by physiological dormancy, a long cold stratification period at low temperatures for dormancy break, formation of a persistent soil seed bank, and annual dormancy/non-dormancy cycling in buried seeds. Results from this study shed light on Short’s bladderpod regeneration biology and have implications for population management.

Contributing Author(s): 
Date Recorded: 
Wednesday, March 4, 2020

Alexander G. Linan, Porter P. Lowry II, Allison Miller, George E. Schatz, Jean-Claude Sevathian, Christine E. Edwards, Saint Louis University, Missouri Botanical Garden, Institut de Systématique, Évolution et Biodiversité (ISYEB), Centre National de la Recherche Scientifique/Muséum National d'Histoire Naturelle/École, Pratique des Hautes Études, Université Pierre et Marie Curie, Sorbonne Universités, Donald Danforth Plant Science Center

The ebony and persimmon genus (Diospyros) is a diverse group of largely tropical trees and shrubs, comprising >800 species, many of which are poorly known, and/or are of dire conservation concern. Some of the most endangered members of the genus are endemic to islands of the Western Indian Ocean. The Mascarene Islands, comprising the islands Reunion, Rodrigues, and Mauritius is located east of Madagascar, and harbor 14 endemic species of Diospyros. Most of the species diversity is endemic to Mauritius are of dire conservation concern with the majority of species listed as either Critically Endangered or Endangered by IUCN Red List assessments. Despite their conservation status, nothing is known about patterns of genetic diversity or whether these sympatrically distributed and closely related species represent distinct genetic units. In this study we conducted population level sampling on all extant species of endemic Mascarene Diospyros and genotyped samples using 2bRAD seq in order to: 1) clarify species limits within the group, 2) determine and compare levels of genetic diversity across species and, 3) assess patterns of genetic structure within species and prioritize populations for conservation efforts. We found the morphologically described species correspond to unique genetic units despite the presence of hybrids and provide recommendations for future/ongoing conservation efforts.

Date Recorded: 
Wednesday, September 11, 2019

CPC Best Reintroduction Practice Guidelines: Astragalus bibullatus Case Study

Matthew Albrecht, Missouri Botanical Garden (SePPCon 2016)

Reintroduction is a critical component of rare species conservation with the goal of continuing evolution in a natural context. Within the southeastern U.S. 81% of recovery plans include reintroduction as a proposed conservation action, while in Hawaii almost all plant recovery plans recommend reintroduction to ensure persistence in the wild. Following CPC Reintroduction Guidelines can help improve success. Ex situ conservation and in situ habitat management should precede reintroduction. Prior to reintroduction gathering information about species biology, genetics, mating system, interactions and habitat is advised.  Aspects of designing a reintroduction include considering genetic,demographic and horticulture. Whether a single or mixed genetic source should be used, how large a founding population and more questions are addressed.    Using an example of Astragalus bibullatus, Matthew describes several aspects of using experimentation to test hypotheses for improving reintroduction success.

This work was presented at the Southeast Partners in Plant Conservation (SePPCon) 2016 Meeting. Learn more about SePPCon here.

Contributing Author(s): 
Date Recorded: 
Tuesday, November 1, 2016

Matthew Albrecht, Missouri Botanical Garden

Monitoring is a central component of reintroduction programs, but often receives less attention from practitioners than the preparation or implementation phases of a project. A well-designed monitoring program can detect changes in the environment over time, identify new threats that emerge at the reintroduction site, determine drivers of growth rates in reintroduced populations, and inform adaptive management. This presentation highlights the ten key components of a well-designed monitoring program based on the CPC's Best Plant Conservation Practices.  Topics discussed includes monitoring objectives and designs for short- and long-lived plant species, threat detection, evaluating fecundity and dispersal, comparisons with wild reference populations, types of data analyses, and best-practices for data management and sharing.

Contributing Author(s): 
Date Recorded: 
Friday, May 3, 2019