Looking for a successful translocation: the case of Astragalus edulis

Abstract

Astragalus edulis (Fabaceae) is an endangered annual plant species from the western Mediterranean region. It occurs in the Iberian Peninsula (SE), Morocco (two main locations in the NE and SW), and the easternmost Canary Islands (Lanzarote and Fuerteventura). After a thorough study assessing genetic diversity and phylogeographic patterns, and a proposal of a management plan to preserve the genetic diversity across the entire area of the species, it is about time to go further in the species conservation. It is necessary to recognize genetically impoverished populations to be able to successfully reinforce populations and find realistic places for translocations. For this, Nei’s genetic diversity values were calculated for the three geographic areas and for their populations. Diversity values were further evaluated to calculate the optimal contribution for the populations within each area to maximize the genetic pool. To evaluate whether the optimum habitat for the species is expected to grow or decrease under a climate change scenario, the optimal model of current climatic suitability of A. edulis was projected into the IPCC (2070_RCP8.5) future scenario. The different geographical areas showed similar genetic diversity values. The populations that contribute to maximize the genetic pool in each geographic area were similar, but not equal, to those proposed in previous studies. The future potential habitat for the species shows a significant range decline, which will affect translocation efforts.

Conservation and Phylogeography of Plants: From the Mediterranean to the Rest of the World

“…Molecular markers and habitat differences should be used in combination to delineate phylogeographic groups, which provide the basis for designing "seed zones" (e.g., [115,[122][123][124][125]). Several examples can be found about the use of molecular markers to delineate the seed zones [20,120,126,127].…”

“…The last consideration involved gathering seeds, and taking into account that sometimes the number of available seeds in the populations is extremely scarce, some authors have proposed the calculations of the optimal proportions of the populations in order to create optimal genetic diversity seed banks [126,127]. This would ensure the gathering of all the genetic diversity of the seed areas, and at the same time, it would respect the natural populations in order not to generate a negative effect [136].…”