While knowledge of the partitioning of genetic diversity itself is a potentially relevant parameter of biodiversity, we are systematically studying the significance of genetic and phytochemical diversity of the dominant ecosystem component (Scots pine), to diversity of other ecosystem components and ecosystem functioning.

The significance to the ecosystem of the monoterpenes and phenolic plant secondary metabolites, lies in their abundance and their antibiotic and anti-herbivore properties (Rosenthal & Janzen, 1979). For example, genetic-differences between trees provide differential resistance to insect pests and associated fungal attack via the resistance mechanisms of non-preference or antibiosis (Speight & Wainhouse, 1989). Specific phytochemicals also act as chemical attractants for insect herbivores that exploit damaged bark, branches or shoots. The antibiotic properties of terpenes and phenolics, and the complexation of phenolic polymers, such as condensed tannins, with proteins and polysaccharides, negatively influences both vertebrate herbivore digestion and the rates of soil processes such as litter decomposition and nitrogen mineralisation. As well as being antifungal, toxic to Gram positive bacteria, allelopathic against seed germination, and repellent to deer (Duncan et al., 1994) and voles (Harborne, 1991), terpenoids also inhibit nitrifying bacteria (White, 1994). We are testing the hypothesis that concentration and ratios of potentially allelochemic secondary metabolites varies spatially among individuals within a Scots pine population and that this generates significant spatial variation in ecosystem function and species composition due to allelochemical interactions.

Contact: Glenn Iason