Darwin's wind hypothesis: does it work for plant dispersal in fragmented habitats?
Using the wind-dispersed plant Mycelis muralis, we examined how landscape fragmentation affects variation in seed traits contributing to dispersal. Inverse terminal velocity (Vt(-1)) of field-collected achenes was used as a proxy for individual seed dispersal ability. We related this measure to different metrics of landscape connectivity, at two spatial scales: in a detailed analysis of eight landscapes in Spain and along a latitudinal gradient using 29 landscapes across three European regions. In the highly patchy Spanish landscapes, seed Vt(-1)increased significantly with increasing connectivity. A common garden experiment suggested that differences in Vt(-1) may be in part genetically based. The Vt(-1) was also found to increase with landscape occupancy, a coarser measure of connectivity, on a much broader (European) scale. Finally, Vt(-1)was found to increase along a south-north latitudinal gradient. Our results for M. muralis are consistent with 'Darwin's wind dispersal hypothesis' that high cost of dispersal may select for lower dispersal ability in fragmented landscapes, as well as with the 'leading edge hypothesis' that most recently colonized populations harbour more dispersive phenotypes.
Riba
Miquel
M
CREAF (Center for Ecological Research and Forestry Applications), Autonomous University of Barcelona, ES-08193 Bellaterra, Spain.
Mayol
Maria
M
CREAF (Center for Ecological Research and Forestry Applications), Autonomous University of Barcelona, ES-08193 Bellaterra, Spain.
Giles
Barbara E
BE
Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden.
Ronce
Ophélie
O
Université Montpellier 2, Institut des Sciences de l'Evolution, UMR CNRS 5554, Place Eugène Bataillon, F-34095 Montpellier cedex 05, France.
Imbert
Eric
E
Université Montpellier 2, Institut des Sciences de l'Evolution, UMR CNRS 5554, Place Eugène Bataillon, F-34095 Montpellier cedex 05, France.
Van Der Velde
Marco
M
Animal Ecology Group, Centre for Ecological and Evolutionary Studies, University of Groningen, PO Box 14, NL-9750 AA Haren, The Netherlands.
Chauvet
Stéphanie
S
Université Montpellier 2, Institut des Sciences de l'Evolution, UMR CNRS 5554, Place Eugène Bataillon, F-34095 Montpellier cedex 05, France.|Association Tela Botanica, Institut de Botanique, 163 Rue Auguste Broussonnet, F-34090 Montpellier, France.
Ericson
Lars
L
Department of Ecology and Environmental Science, Umeå University, SE-901 87 Umeå, Sweden.
Bijlsma
R
R
Population and Conservation Genetics, Theoretical Biology, University of Groningen, PO Box 14, NL-9750 AA Haren, The Netherlands.
Vosman
Ben
B
Plant Research International, Wageningen UR, PO Box 16, NL-6700 AA Wageningen, The Netherlands.
Smulders
M J M
MJM
Plant Research International, Wageningen UR, PO Box 16, NL-6700 AA Wageningen, The Netherlands.
Olivieri
Isabelle
I
Université Montpellier 2, Institut des Sciences de l'Evolution, UMR CNRS 5554, Place Eugène Bataillon, F-34095 Montpellier cedex 05, France.
D019659:Asteraceae / Q000502:physiology*; D017753:Ecosystem; D008954:Models, Biological; D019655:Quantitative Trait, Heritable; D012639:Seeds / Q000502:physiology*; D013030:Spain; D014919:Wind