Abstract Detail

Transplantations and relocation of species at risk: learning from the past to plan for the future

Fant, Jeremie [1], Havens, Kayri [2].

Post-glacial migration, biogeography and genetics of a narrow endemic thistle, Cirsium pitcheri (Asteraceae) : Consequences for restorations.

Narrow endemic species are often limited to locally unique habitats and have lower colonization ability and dispersal distances and consequently are also thought to be at risk of extinction with climate change. Cirsium pitcheri (Pitcher's thistle or dune thistle) is a federally listed rare species restricted to the shorelines of the western Great Lakes and is classified as a narrow endemic. Its preferred habitat is within the dynamic sand dune ecosystems in which natural disturbance cycles, drive the extinction-colonization meta-population dynamics of this species. The preservation of this species will require a better understanding of how colonization is maintained across this most extensive, but narrow linear ecosystem. A number of restorations have attempted to increase the number, size and connectivity of the populations in the southern end of it range. The distribution of neutral genetic diversity, which are not under selection, is determined by phylogenetic history, habitat age, and patterns of drift and gene-flow. We compared current and historic landscape features against genetic distances, in both natural and restored populations to understand how dispersal and meta-population dynamics have influenced isolation by distance and genetic structure in Cirsium pitcheri. We found that this species shows high differentiation associated with low contemporary gene flow. The mosaic of genetic similarity suggests that post-glacial migration and erratic long distance dispersal events, rather than contemporary gene flow, played major roles in determining the current genetic structure and distribution of diversity within this species. This had important implications for southern populations which had lower diversity than more northerly populations. Although population size was correlated with genetic diversity, it was not with inbreeding. This was evident in the mixed-source restorations which had some of the highest genetic diversity within the region but due to low gene-flow, even within a population, had high levels of inbreeding. Measures of genetic diversity, 10-20 years after restoration began revealed that the some source populations contributed more to the genetic makeup of the populations than others.

Broader Impacts:

1 - Chicago Botanic Gardens, 1000 Lake Cook Rd, Glencoe, IL, 60022, USA
2 - Chicago Botanic Garden, CONS SCI DEPT, 1000 Lake Cook Road, Glencoe, IL, 60022, USA

Keywords:
 Cirsium pitcheri
gene flow
microsatellites
narrow endemic
population genetics
post-glacial migration
endangered species.

Presentation Type: Symposium or Colloquium Presentation
Session: SY08
Location: Delaware A/Hyatt
Date: Wednesday, July 11th, 2012
Time: 8:45 AM
Number: SY08002
Abstract ID:176