Get access

Population genetics and conservation of critically small cycad populations: a case study of the Albany Cycad, Encephalartos latifrons (Lehmann)

Authors

  • JESSICA M. DA SILVA,

    Corresponding author
    1. Applied Biodiversity Research, Kirstenbosch Research Centre, South African National Biodiversity Institute, Private Bag X7, Claremont 7735, Cape Town, South Africa
    2. Percy FitzPatrick Institute of African Ornithology, Department of Zoology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa
    Search for more papers by this author
  • JOHN S. DONALDSON,

    1. Applied Biodiversity Research, Kirstenbosch Research Centre, South African National Biodiversity Institute, Private Bag X7, Claremont 7735, Cape Town, South Africa
    Search for more papers by this author
  • GAIL REEVES,

    1. Percy FitzPatrick Institute of African Ornithology, Department of Zoology, University of Cape Town, Rondebosch 7701, Cape Town, South Africa
    Search for more papers by this author
  • TERRY A. HEDDERSON

    1. Bolus Herbarium, Department of Botany, University of Cape Town, Private Bag Rondebosch 7701, Cape Town, South Africa
    Search for more papers by this author

E-mail: jessica.m.dasilva@gmail.com

Abstract

Declining populations of less than 250 mature individuals are symptomatic of many Critically Endangered cycads, which, globally, comprise the most threatened group of organisms as a result of collecting and habitat loss. Survival plans focus on law enforcement, reintroduction, and augmentation programmes using plants from the wild and botanical gardens. Augmentation is one of the few remaining options for cycad populations, although the assumed benefits remain untested and there is a possibility that augmentation from different sources could compromise the genetic integrity of existing populations, especially when garden plants have no provenance data. We studied Encephalartos latifrons, a South African endemic, which is a typical Critically Endangered cycad. We studied the extent and structure of genetic diversity in wild and ex situ populations to assess the potential benefits and risks associated with augmentation programmes. We examined 86 plants using amplified fragment length polymorphisms (AFLPs). The 417 AFLP markers thus generated yielded a unique DNA ‘fingerprint’ for each plant. Wild populations retain high levels of genetic diversity and this is reflected among the ex situ holdings at the Kirstenbosch Botanical Garden. No population differentiation is evident, indicating a single panmictic population, consistent with moderately high levels of gene flow between subpopulations and a sexual mode of reproduction. Bayesian clustering identified four genotype groups in the wild, as well as a genotype group only found in ex situ collections. Our results indicate that E. latifrons would benefit from augmentation programmes, including the use of undocumented collections, and careful management of breeding plants would increase the heterogeneity of propagules. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 293–308.

Ancillary