TY  - JOUR
A1  - Lauterbach, Daniel
A1  - Ristow, Michael
A1  - Gemeinholzer, Birgit
T1  - Population genetics and fitness in fragmented populations of the dioecious and endangered Silene otites (Caryophyllaceae)
JF  - Plant systematics and evolution
N2  - Population fragmentation is often correlated with loss of genetic diversity and reduced fitness. Obligate out-crossing (dioecy) is expected to enhance genetic diversity, reduce genetic differentiation, and avoid inbreeding depression through frequent gene flow. However, in highly fragmented populations dioecy has only diminishing effects upon genetic structure as pollination limitations (e.g. flight distance of pollinators) most often restrict inter-population gene flow in insect pollinated species. In fragmented dry grasslands in northeastern Germany, we analysed genetic structure, fitness, and habitat quality of the endangered dioecious Silene otites (Caryophyllaceae). Using AFLP markers, a high level of differentiation among ten populations was found (F (st) = 0.36), while the intra-population genetic diversities (H (E) = 0.165-0.240) were similar as compared to hermaphroditic species. There was neither a correlation between geographic and genetic distance nor between genetic diversity and population size, which indicates reduced gene flow among populations and random genetic drift. Plant size was positively correlated with genetic diversity. Seed set and number of juveniles were positively related to population size. Higher total coverage resulted in reduced plant fitness, and the number of juveniles was negatively correlated to cryptogam cover. Additionally, we found a sex ratio bias towards more male plants in larger populations. Overall, our results indicate that on a regional geographic scale dioecy does not necessarily prevent genetic erosion in the case of habitat fragmentation, especially in the absence of long distance seed and pollen dispersal capacity.
KW  - AFLP
KW  - Population size
KW  - Mating system
KW  - Isolation by distance
KW  - Sex ratio
Y1  - 2012
U6  - https://doi.org/10.1007/s00606-011-0533-0
SN  - 0378-2697
VL  - 298
IS  - 1
SP  - 155
EP  - 164
PB  - Springer
CY  - Wien
ER  - 
TY  - JOUR
A1  - Lauterbach, Daniel
A1  - Burkart, Michael
A1  - Gemeinholzer, Birgit
T1  - Rapid genetic differentiation between ex situ and their in situ source populations - an example of the endangered Silene otites (Caryophyllaceae)
JF  - Botanical journal of the Linnean Society
N2  - Ex situ cultivation in botanic gardens could be one possibility to preserve plant species diversity and genetic variation. However, old ex situ populations are often sparsely documented. We were able to retrieve three different ex situ populations and their source in situ populations of the endangered plant species Silene otites after 20-36 years of isolation. Furthermore, three additional wild populations were included in the analysis. Population genetic diversity and differentiation were analysed using AFLP markers. Genetic variation in the ex situ populations was lower than the variation found in the in situ populations. Strong differentiation (F-ST = 0.21-0.36) between corresponding in situ and ex situ populations was observed. Bayesian clustering approach also showed a distinct genetic separation between in situ and ex situ populations. The high genetic differentiation and loss of genetic diversity during spatial and temporal isolation in the ex situ populations can be attributable to small population sizes and unconscious selection during cultivation. Therefore, adequate sampling prior to ex situ cultivation and large effective population sizes are important to preserve genetic diversity. Near-natural cultivation allowing for generation overlap and interspecific competition without artificial selection is recommended as being best for the maintenance of the genetic constitution.
KW  - AFLP
KW  - botanical garden
KW  - conservation genetics
KW  - founder effect
KW  - population size
Y1  - 2012
U6  - https://doi.org/10.1111/j.1095-8339.2011.01185.x
SN  - 0024-4074
VL  - 168
IS  - 1
SP  - 64
EP  - 75
PB  - Wiley-Blackwell
CY  - Hoboken
ER  -