Spatially explicit and multi-sourced genetic information is critical for conservation of an endangered plant species, San Diego thornmint (Acanthomintha ilicifolia)

• Published in: Conservation genetics Vol. 19; no. 4; pp. 893 - 907
• Main Authors: DeWoody, J., Rogers, D. L., Hipkins, V. D., Endress, B. A.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01-08-2018; Springer Nature B.V
• Subjects: Acanthomintha ilicifolia; Animal Genetics and Genomics; Biodiversity; Biomedical and Life Sciences; Conservation; Conservation Biology/Ecology; Cytometry; Ecology; Endangered plants; Endangered species; Evolutionary Biology; Flow cytometry; Genetic diversity; Genetic structure; Germplasm; Life Sciences; Plant Genetics and Genomics; Plant populations; Plant species; Population genetics; Population studies; Population viability; Populations; Research Article; San Diego thornmint; Wildlife conservation; Population genetic structure; Ploidy; Local adaptation
• ISSN: 1566-0621; 1572-9737
• DOI: 10.1007/s10592-018-1062-y

San Diego thornmint
Acanthomintha ilicifolia
(Gray) Gray (Lamiaceae) is a winter herb restricted to San Diego county in the United States and Baja California Norte in Mexico. Historic records document 80 occurrences of this species, with 55 extant occurrences in San Diego County currently known. We compared three measures of genetic variation to inform ongoing conservation efforts: putatively neutral genetic structure revealed from isozyme markers, apparent cytogenetic variation confirmed using flow cytometry, and potentially adaptive morphological variation quantified in a common-garden study. Together, these data indicated that this rare endemic is genetically complex, revealing significant differentiation of neutral and potentially adaptive genetic variation among populations, and possessing at least two cytotypes, sometimes even within the same population. While additional study is required to resolve the extent of potential local adaptation in this species, conservation plans should limit the movement of germplasm among occurrences and monitor populations in order to limit potential long-term impacts to population viability. Given that these findings challenge the canonical model of genetic structure in rare plants (low genetic variation and limited genetic structure), we recommend guidelines to apply genetic information to conservation strategies.