Abstract Detail

Conservation Biology

White, Abbey [1], Kramer, Andrea [2], Fant, Jeremie [1].

Understanding genetic diversity, clonality, and demography to inform restoration of a vulnerable Great Lakes endemic thistle, Cirsium hillii (Asteraceae).

Vulnerable plant species receive limited attention because they are neither common enough to warrant wider study, nor rare enough to be prioritized for recovery. Although vulnerable species increase diversity in a system and can provide important ecosystem functions and services, they are rarely included in restoration work. One representative vulnerable species is Cirsium hillii (Hill’s Thistle), a northern native thistle endemic to the Great Lakes region, where it inhabits two very different types of xeric habitat – gravel hills and sandy prairies. Listed as globally vulnerable, C. hillii has a wide distribution with a few populations that are large and reproductively active, but most populations are small, fragmented, and at risk of local extinction. C. hillii rarely flowers and many populations show low reproductive success and have poor seed production, making it difficult to include this species in restoration mixes. Some C. hillii populations seem to persist via asexual, clonal reproduction, although the extent to which it relies on clonal growth is mostly unknown. When it does flower, C. hillii is thought to be self-incompatible, and this, combined with low genetic diversity and small population numbers, may further reduce seed set. In this study, we use microsatellite markers to investigate the extent of clonal growth, genetic diversity, and genetic structure in seven populations of C. hillii. We found limited genetic diversity within a population and extremely high clonality, but high diversity between populations. Our results indicate that asexual reproduction may be the primary mode of reproduction in this species; with increasing fragmentation, the apparent reduced sexual reproduction may necessitate alternative restoration efforts. This study highlights the importance of understanding clonal structure when determining the population dynamics of a clonal species, as field observations based on the number of plants will likely overestimate the effective population size. Recovery strategies for C. hillii should focus on increasing the genotypic diversity at each site.

1 - Chicago Botanic Garden/Northwestern University, Plant Biology and Conservation, 1000 Lake Cook Road, Glencoe, IL, 60022, USA
2 - Chicago Botanic Garden, 1000 Lake Cook Road, Glencoe, IL, 60022, USA

Keywords:
clonality
asexual reproduction
Cirsium hillii
population genetics
Microsatellite
gravel/sandy prairies.

Presentation Type: Oral Paper
Session: 26, Conservation Biology I
Location: 104/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 2:30 PM
Number: 26005
Abstract ID:841
Candidate for Awards:None