PARENT SESSION
Contributed Oral Session 111: Biodiversity: Genetics and Evolution
Thursday, August 11, 8:00 AM - 11:30 AM, Meeting Room 513 E, Level 5, Palais des congrès de Montréal

The role of intraspecific genetic diversity on spatial vegetation dynamics.

Bilton, Mark^{*,1, 2, 3}, Birch, Colin¹, Pakeman, Robin¹, Grime, J.Philip², Marion, Glenn³, ¹ The Macaulay Institute, Aberdeen, UK² University of Sheffield, Sheffield, UK³ BioSS, Edinburgh, UK

ABSTRACT- Biodiversity can be studied at many scales. Most previous research has focused on species richness within communities. While the potential importance of within species diversity has been acknowledged, it has been relatively unexplored. A long term experiment was set up in 1998 to investigate the effect of intraspecific genetic diversity on plant community structure and dynamics. Established individuals, were removed at random from a small area within an ancient species rich calcareous grassland, and clonally propagated to produce model communities identical in species composition but containing 3 levels of genetic diversity (1, 4 or 16 genotypes per species). Relative species abundance varied considerably across the 1 genotype boxes, but was relatively invariable across replicates of the 16 genotype communities. Specific genotypic traits of dominant species, such as growth rate, could contribute to the differences, but interspecific associations influenced by genotypic traits may play a key role in the coexistence of some species. Fine scale observations showed that species express clearly definable spatial patterns. Models based solely on distance from planting position and distance from the box edge can predict a large part of some of the observed species distributions. These models are useful indicators of plant growth strategies. For example, they indicate mobility and persistence at occupied sites. When combined with species richness data, these models also show the local interference effects of certain species. A novel technique has been developed to identify significant associations of pairs or groups of species in local neighborhoods which could be linked to morphological and physiological genotypic traits. Some of the local species associations (0.04m²) contrast with the species correlations found at the whole box level (0.56m²). Having established that intraspecific diversity affects community structure, do genetically determined traits affect the dominance hierarchy directly or through modifying species associations?

Key words: Genetic Diversity, Species Associations