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Increased genetic differentiation but no reduced genetic diversity in peripheral vs. central populations of a steppe grass
Author(s) -
Wagner Viktoria,
Durka Walter,
Hensen Isabell
Publication year - 2011
Publication title -
american journal of botany
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.218
H-Index - 151
eISSN - 1537-2197
pISSN - 0002-9122
DOI - 10.3732/ajb.1000385
Subject(s) - biology , genetic diversity , population , range (aeronautics) , genetic drift , evolutionary biology , genetic structure , genetic variation , gene flow , ecology , intraspecific competition , genetics , demography , gene , materials science , sociology , composite material
• Premise of the Study: Intraspecific genetic variation is essential for the performance and evolution of species. Populations at a species’ geographic range periphery receive considerable attention in biogeography and conservation because they are smaller and spatially more isolated than central populations, a pattern expected to lead to higher genetic differentiation and lower within‐population genetic diversity. We tested these predictions in central and peripheral populations of the Eurasian steppe grass Stipa capillata . • Methods: We analyzed AFLP fingerprint patterns in 319 individuals from 20 large and abundant populations in the core, in Kazakhstan, and 23 small and isolated populations at the periphery, in Central Europe. We calculated different genetic diversity estimates and assessed genetic differentiation among populations by examining F ST values, a neighbor‐net network, and an AMOVA. • Key Results: As expected, genetic differentiation among populations was significantly larger at the range periphery ( F ST = 0.415) than in the range core ( F ST = 0.164). In contrast to predictions, however, we found similarly low genetic diversity within central (proportion of polymorphic bands = 21.9%) and peripheral (20%) populations. • Conclusions: Higher genetic differentiation in the small and spatially isolated peripheral populations is likely driven by genetic drift and reduced gene flow due to a complex landscape structure and the abandonment of traditional management regimes. With regard to unchanged genetic diversity, it appears that life‐history traits like longevity or sufficiently large population sizes could allow S . capillata to escape deleterious effects at the range edge.