Non-additive effects of genotypic diversity increase floral abundance and abundance of floral visitors.
BACKGROUND
In the emerging field of community and ecosystem genetics, genetic variation and diversity in dominant plant species have been shown to play fundamental roles in maintaining biodiversity and ecosystem function. However, the importance of intraspecific genetic variation and diversity to floral abundance and pollinator visitation has received little attention.


RESULTS
Using an experimental common garden that manipulated genotypic diversity (the number of distinct genotypes per plot) of Solidago altissima, we document that genotypic diversity of a dominant plant can indirectly influence flower visitor abundance. Across two years, we found that 1) plant genotype explained 45% and 92% of the variation in flower visitor abundance in 2007 and 2008, respectively; and 2) plant genotypic diversity had a positive and non-additive effect on floral abundance and the abundance of flower visitors, as plots established with multiple genotypes produced 25% more flowers and received 45% more flower visits than would be expected under an additive model.


CONCLUSIONS
These results provide evidence that declines in genotypic diversity may be an important but little considered factor for understanding plant-pollinator dynamics, with implications for the global decline in pollinators due to reduced plant diversity in both agricultural and natural ecosystems.
Genung
Mark A
MA
Department of Ecology and Evolutionary Biology, University of Tennessee, Knoxville, Tennessee, United States of America. mgenung@utk.edu
Lessard
Jean-Philippe
JP
Brown
Claire B
CB
Bunn
Windy A
WA
Cregger
Melissa A
MA
Reynolds
W M Nicholas
WM
Felker-Quinn
Emmi
E
Stevenson
Mary L
ML
Hartley
Amanda S
AS
Crutsinger
Gregory M
GM
Schweitzer
Jennifer A
JA
Bailey
Joseph K
JK
D035264:Flowers; D014644:Genetic Variation; D005838:Genotype; D013045:Species Specificity