Demographic structure and genetic variability throughout the distribution of Platte thistle (Cirsium canescens Asteraceae)

• DOI: 10.1111/jbi.12879
• Publication Date: 2016-11-02T19:23:38Z
• Authors: Robby L. McMinn; F. Leland Russell; James B. Beck
• Keywords: Isolation by distance; Species distribution; Population density

Abstract Aim Understanding spatial variation in the demographic and genetic structure of populations is central to explaining causes species range limits conservation. The Abundant Centre Hypothesis (ACH) predicts that as one moves away from centre a species’ biogeographical range, become less frequent more isolated, well exhibiting decreasing within‐population density. This increased isolation may lead reduced variability peripheral by limiting gene flow. In this study, we asked whether frequency, density diversity Cirsium canescens (Platte thistle) decreased edge, predicted ACH. Location Central United States, including portions Great Plains Rocky Mountains. Methods Frequency population occurrence at regional landscape scales, density, were evaluated along eight centre‐edge transects within distribution. Leaf tissue samples collected each establish using six simple sequence repeat loci. Results Consistent with ACH, regions C. ’ likely contain than regions. where did occur, however, frequency scale peaked intermediate distances was unrelated distance. Populations exhibited towards edges. Main conclusions ACH underestimates complexity relationship between abundance distance canescens’ centre. Decreases Platte thistle combined no decreases near edges suggest quality habitat exists but these patches are rarer. Although distribution edges, decline stronger western associated topographic complexity.