Genetic analyses of Astragalus sect. Humillimi (Fabaceae) resolve taxonomy and enable effective conservation

Rob Massatti, Matthew T. Belus, Shahed Dowlatshahi, Gerard J Allan

Research output: Contribution to journalArticle

Abstract

Premise of the Study: Astragalus sect. Humillimi is distributed across the southwestern United States and contains two endangered taxa, A. cremnophylax var. cremnophylax and A. humillimus. The former was originally described from the South Rim of the Grand Canyon. Analysis of individuals discovered on the North Rim of the Grand Canyon yielded some evidence that the population represented a distinct species. To enable effective conservation, we clarify the group's taxonomy and characterize the genetic diversity of A. cremnophylax and A. humillimus. Methods: We used AFLPs to genotype most species in sect. Humillimi, focusing on the two endangered forms. We examined patterns of genetic diversity using complementary analytical approaches. Key Results: Our results demonstrate that North Rim populations group with A. c. var. cremnophylax. We found low levels of genetic diversity at certain localities and strong differentiation among populations. Astragalus humillimus, which has suffered recent and severe population declines, exhibits weak differentiation among and low diversity within populations. Conclusions: Our results clarify the taxonomy of sect. Humillimi and define the boundaries of A. c. var. cremnophylax, which is shown to inhabit both rims of the Grand Canyon. This clarification, and detailed analysis of genetic variation within both endangered taxa, may advance ongoing efforts to conserve these taxa. Our results suggest that range-wide genetic analysis of A. humillimus may inform recovery strategies for this taxon.

Original languageEnglish (US)
Pages (from-to)1703-1711
Number of pages9
JournalAmerican Journal of Botany
Volume105
Issue number10
DOIs
StatePublished - Oct 1 2018

Fingerprint

Astragalus
Fabaceae
canyon
taxonomy
canyons
genetic variation
Population
Southwestern United States
genetic analysis
population decline
genotype
Genotype
amplified fragment length polymorphism
genetic techniques and protocols
genetic diversity
analysis

Keywords

  • Astragalus cremnophylax
  • Astragalus humillimus
  • endangered
  • Grand Canyon
  • population genetics
  • sentry milk-vetch
  • southwestern United States

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Genetics
  • Plant Science

Cite this

Genetic analyses of Astragalus sect. Humillimi (Fabaceae) resolve taxonomy and enable effective conservation. / Massatti, Rob; Belus, Matthew T.; Dowlatshahi, Shahed; Allan, Gerard J.

In: American Journal of Botany, Vol. 105, No. 10, 01.10.2018, p. 1703-1711.

Research output: Contribution to journalArticle

Massatti, Rob ; Belus, Matthew T. ; Dowlatshahi, Shahed ; Allan, Gerard J. / Genetic analyses of Astragalus sect. Humillimi (Fabaceae) resolve taxonomy and enable effective conservation. In: American Journal of Botany. 2018 ; Vol. 105, No. 10. pp. 1703-1711.
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