Christoph Rosche1,2, Annett Baasch3, Karen Runge3, Philipp Brade3, Sabrina Träger1,2, Christian Parisod4, Isabell Hensen1,2. 1. Martin Luther University Halle-Wittenberg, Institute of Biology/Geobotany and Botanical Garden, Große Steinstraße 79/80, 06108 Halle (Saale), Germany. 2. German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Puschstraße 4, 04103 Leipzig, Germany. 3. Anhalt University of Applied Sciences, Department of Agriculture, Ecotrophology and Landscape Development, Strenzfelder Allee 28, 06406 Bernburg (Saale), Germany. 4. University of Fribourg, Department of Biology, Chemin du Musée 10, 1700 Fribourg, Switzerland.
Abstract
BACKGROUND AND AIMS: Habitat degradation and landscape fragmentation dramatically lower population sizes of rare plant species. Decreasing population sizes may, in turn, negatively affect genetic diversity and reproductive fitness, which can ultimately lead to local extinction of populations. Although such extinction vortex dynamics have been postulated in theory and modelling for decades, empirical evidence from local extinctions of plant populations is scarce. In particular, comparisons between current vs. historical genetic diversity and differentiation are lacking despite their potential to guide conservation management. METHODS: We studied the population genetic signatures of the local extinction of Biscutella laevigata subsp. gracilis populations in Central Germany. We used microsatellites to genotype individuals from 15 current populations, one ex situ population, and 81 herbarium samples from five extant and 22 extinct populations. In the current populations, we recorded population size and fitness proxies, collected seeds for a germination trial and conducted a vegetation survey. The latter served as a surrogate for habitat conditions to study how habitat dissimilarity affects functional connectivity among the current populations. KEY RESULTS: Bayesian clustering revealed similar gene pool distribution in current and historical samples but also indicated that a distinct genetic cluster was significantly associated with extinction probability. Gene flow was affected by both the spatial distance and floristic composition of population sites, highlighting the potential of floristic composition as a powerful predictor of functional connectivity which may promote decision-making for reintroduction measures. For an extinct population, we found a negative relationship between sampling year and heterozygosity. Inbreeding negatively affected germination. CONCLUSIONS: Our study illustrates the usefulness of historical DNA to study extinction vortices in threatened species. Our novel combination of classical population genetics together with data from herbarium specimens, an ex situ population and a germination trial underlines the need for genetic rescue measures to prevent extinction of B. laevigata in Central Germany.
BACKGROUND AND AIMS: Habitat degradation and landscape fragmentation dramatically lower population sizes of rare plant species. Decreasing population sizes may, in turn, negatively affect genetic diversity and reproductive fitness, which can ultimately lead to local extinction of populations. Although such extinction vortex dynamics have been postulated in theory and modelling for decades, empirical evidence from local extinctions of plant populations is scarce. In particular, comparisons between current vs. historical genetic diversity and differentiation are lacking despite their potential to guide conservation management. METHODS: We studied the population genetic signatures of the local extinction of Biscutella laevigata subsp. gracilis populations in Central Germany. We used microsatellites to genotype individuals from 15 current populations, one ex situ population, and 81 herbarium samples from five extant and 22 extinct populations. In the current populations, we recorded population size and fitness proxies, collected seeds for a germination trial and conducted a vegetation survey. The latter served as a surrogate for habitat conditions to study how habitat dissimilarity affects functional connectivity among the current populations. KEY RESULTS: Bayesian clustering revealed similar gene pool distribution in current and historical samples but also indicated that a distinct genetic cluster was significantly associated with extinction probability. Gene flow was affected by both the spatial distance and floristic composition of population sites, highlighting the potential of floristic composition as a powerful predictor of functional connectivity which may promote decision-making for reintroduction measures. For an extinct population, we found a negative relationship between sampling year and heterozygosity. Inbreeding negatively affected germination. CONCLUSIONS: Our study illustrates the usefulness of historical DNA to study extinction vortices in threatened species. Our novel combination of classical population genetics together with data from herbarium specimens, an ex situ population and a germination trial underlines the need for genetic rescue measures to prevent extinction of B. laevigata in Central Germany.
Authors: Patrick M A James; Dave W Coltman; Brent W Murray; Richard C Hamelin; Felix A H Sperling Journal: PLoS One Date: 2011-10-04 Impact factor: 3.240
Authors: S Henrik Barmentlo; Patrick G Meirmans; Sheila H Luijten; Ludwig Triest; J Gerard B Oostermeijer Journal: Conserv Genet Date: 2017-12-01 Impact factor: 2.538
Authors: Richard G J Hodel; M Claudia Segovia-Salcedo; Jacob B Landis; Andrew A Crowl; Miao Sun; Xiaoxian Liu; Matthew A Gitzendanner; Norman A Douglas; Charlotte C Germain-Aubrey; Shichao Chen; Douglas E Soltis; Pamela S Soltis Journal: Appl Plant Sci Date: 2016-06-16 Impact factor: 1.936