|
|
||||||||
|
(American Journal of Botany. 2008;95:1254-1261.) doi: 10.3732/ajb.2007159 © 2008 Botanical Society of America, Inc. |
What's this? |
Population Biology |
2 Biology Department, Appalachian State University, Boone, North Carolina 28607 USA 3 Plant Biology Department, University of Georgia, Athens, Georgia 30602 USA 4 Department of Ecology, Evolution & Natural Resources, Rutgers University, 14 College Farm Road, New Brunswick, New Jersey 08901-8551 USA
ABSTRACT
The balance between clonal and sexual reproduction can vary widely among plant populations, and the extent of clonality may be influenced by the combined effects of historical land use and variation in environmental conditions. We investigated patterns of clonal spread in five Trillium cuneatum populations, two in the Appalachian Mountains characterized by mesic, cooler conditions, and three at lower elevations experiencing warmer, drier conditions and greater disturbance. Using a new measure of the genet effective number and innovative orthogonal contrast methods, we quantified genet structure, contrasting clonal growth in the mountains with that in the Piedmont. Asexual propagation was more common in the Piedmont, where 25% of the sampled ramets were clonally derived, but was much less frequent in the mountains (7% clonal replicates). Hierarchical partitioning of variation in genet diversity showed that the majority (75.8%) of the variation resulted from more vegetative replication in the Piedmont. Most of the remaining variation (21.6%) was attributable to differences between urban and rural Piedmont populations, and a small, statistically nonsignificant fraction of the variation (2.6%) was due to interpopulation differences within the mountains. Higher frequency of cloning may enhance both genetic and demographic population viability in fragmented Piedmont habitats.
Key Words: clonal structure genet diversity heterogeneous environments orthogonal contrasts Southeastern USA vegetative reproduction Trillium
Received for publication 22 May 2007. Accepted for publication 14 July 2008.
FOOTNOTES
1 The authors wish to thank R. Pulliam for helpful comments on the manuscript and for sharing his unpublished weather data. M. Arnold, J. Avise, S. M. Chang and J. J. Robledo reviewed previous versions of this manuscript. They also greatly appreciate field and laboratory assistance by C. Deen, L. Kappa, S. Conrad, and K. and T. Bercikova. This research was supported by funds from the Department of Plant Biology Palfrey Fund to E.G., by NSF-DEB0211526 to J.L.H. and by NSF-GRS0327147 to J.L.H. and E.G. P.E.S. was funded by NJAES/USDA-17111 and by NSF-DEB-0211430.
5 Author for correspondence: (e-mail: gonzaleseb{at}appstate.edu)
![]()
CiteULike
Complore
Connotea
Del.icio.us
Digg
Facebook
Reddit
Technorati
Twitter What's this?
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |