Canal-U

[COLLOQUE] GENTREE Final Conference 27-31 January 2020 séance 18

GENTREE Final Conference :

Sean HOBAN - The Morton Arboretum Lisle · USA

GENTREE Final Conference 'Genetics to the rescue - managing forests sustainably in a changing environment'

27-31 January 2020, Avignon, France

http://www.gentree-h2020.eu/

Sean HOBAN - The Morton Arboretum Lisle · USA : Conserving genetic diversity in botanic gardens: calculating how much to conserve

Ex situ collections such as botanic gardens inspire and educate the public, provide material for scientific study, and produce material for ecological restoration.

The challenge for an efficient and effective collection is safeguarding high genetic and ecological diversity in as few samples as possible, due to the relatively small resources available for conservation.

A botanic garden might have resources to maintain a few to a few hundred plants of priority species in conservation collections, but not the thousands that seed banks can preserve.

Providing scientifically grounded recommendations for the number of individuals that need to be conserved, and how to collect from the wild and manage collections over time, is a pressing need.

Previous work using case studies and modeling of important biological traits has established the fact that some species must be sampled differently, and that widely used standard sample sizes might not be optimal practice for capturing diversity.

We present here a comparative study of ex situ gene conservation in 11 species across five genera (oaks, magnolias, cycads, palms and hibiscus).

Specifically, we use genetic datasets and resampling algorithms to: quantify how much genetic diversity has been captured in a global network of botanic garden collections currently; resample the wild population genetic datasets to determine how much genetic diversity could be captured by varying sample sizes; and use a diminishing returns method to calculate optimal stopping points- when additional collection effort no longer provides sufficient gains.

Between 28 and 95% of genetic diversity is currently safeguarded.

Even under an optimistic assumption only eight of the eleven species meet the 70% genetic diversity Target of the Global Strategy for Plant Conservation.

The recommended collection size depends on biological factors as well as (a previously underappreciated factor) key decisions by curators about the type of genetic diversity that is valued, but may range from approximately 50 to 200 individuals.

We hope that these findings motivate future seed collections from wild provenances for botanic garden collections and stimulate discussion on ex situ gene conservation goals and outcomes