genetic diversity

Christa Horn and Joyce Maschinski, San Diego Zoo Global and Center for Plant Conservation

The primary purpose of a conservation collection is to support species’ survival and reduce the extinction risk of globally and/or regionally rare species. A conservation collection is an ex situ (offsite) collection of seeds, plant tissues, or whole plants that has accurate records of provenance, maternal lines differentiated, and diverse genetic representation of a species’ wild populations. To be most useful for species survival in the wild, a conservation collection should have depth, meaning that it contains seeds, tissues or whole plants of at least 50 unrelated mother plants, and breadth, meaning it consists of accessions from multiple populations across the range of the species. Conservation collections of seeds should have tests of initial germination and viability, cultivation protocols developed, and periodic testing of long-term viability.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018

Jordan Wood, Jeremie Fant, Andrea Kramer and Kay Havens, Chicago Botanic Garden

Genetics becomes important whenever populations become small (<100). This includes loss o fgenetic diversity from drift, increased expression of deleterious genes due to inbreeding, and limiting local adaptation. Since many species of plants are able to be seed banked, it is possible to maintain numbers well above these critical genetic thresholds. However for exceptional species, which can only be maintained as living plants, or for critically endangered species where remaining individuals are already below these numbers, the need to consider the remaining genetic diversity becomes critical. Importantly, the management focus shifts from saving a population to preserving each genetically unique individual. When you have such small numbers, it is critical to know how each individual contributes to the overall genetic diversity remaining. We are working with National Tropical Botanic Gardens (Hawaiʻi) to develop a multi-institution species management and breeding plan for Ālula(Brighamia insignis)that will ultimately support its restoration to the wild. To do this we are working with scientists at the Chicago Zoological Society to modify management software that incorporates genetics and demography information to maintain the long-term health of their captive populations of animals over the long term. Through this case study, we hope to develop collections management practices for plants that preserve important genetic diversity while identifying genetically appropriate individuals to using in crosses and that can ultimately be used to create resilient populations that can be used in reintroductions.

Contributing Author(s): 
Date Recorded: 
Friday, May 4, 2018