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Abstract: Data mining techniques were applied to model the presence and abundance of volunteer oilseed rape (OSR) (Brasica napus L.) in the seedbank at 257 arable fields used for baseline sampling in the UK''s Farm Scale Evaluations of genetically modified herbicide tolerant (GMHT) crops. Constructed models were supported by statistical tests. Volunteer OSR was most likely present if a previous OSR crop had been grown in the same field, but it was also present at sites where it had not been grown in the previous 8 years (24% of all fields). In 136 fields where it was found, it showed a slow decline in abundance since the last crop. However, data mining indicated previously unfound correlations between oilseed rape abundance, total seedbank and several other factors, notably percent of nitrogen and percent of carbon in the soil, all of which were smallest in the centre of arable production in southern England and greatest in the surrounding south-west, west and north. In a separate analysis, its abundance was also associated with particular plant life history groups, which include broadleaf weeds such as Capsella and Matricaria species, having a similar phenology to oilseed rape, between rapidly developing annuals and the biennials and perennials. The findings are a reference point in the evolution of oilseed rape as a weed and potential GM impurity. Data mining approaches provide models that may be used to assess the status of volunteer OSR in other countries or at a later time in the UK. [Copyright &y& Elsevier]

A central aim in ecology is to understand the relation between organism diversity and ecosystem functioning. We investigate this relation using a generic individual-based modelling framework described in part 1, in which individuals within a community are characterised by physiological traits and interact within a spatially structured environment. We explore the effect of intraspecific variation among individuals on community-scale productivity in a range of homogeneous and heterogeneous environments. We show that diversity among individuals has a significant, and in most but not all cases positive, impact on community productivity. At low levels of resource the persisting plants giving highest productivity have slowest uptake rates and longest times to reproduction. In contrast, at high levels of resource the persisting plants giving highest productivity have highest uptake levels and shortest time to reproduction. Thus, the individuals’ trait distributions defining community functioning emerge, after many iterations of the model, from the surviving individuals. We, therefore, show that different mechanisms, as evidenced in the surviving individuals’ traits, increase community productivity in different environmental contexts, and so demonstrate the importance of accounting for diversity at the scale of the individual. Consequently, progress may be made in linking diversity and function by considering small, manageable systems and making physiological measurements on individuals. [Copyright &y& Elsevier]

Biodiversity is generally accepted to include both within species and between species variation. Consequently, the contribution to the functioning of ecosystems of variation among individuals should be accounted for. However, very little is known about patterns of diversity below the species level, and less still about the patterns of individual diversity and their relation to ecosystem context and community function. We present a model for the dynamics of individuals that is physiologically based and spatially explicit. Individuals are defined in terms of measurable parameters that relate environmental context to phenotype and in this sense define the genotype. Estimates for the variation in the parameter values are obtained from experiments conducted on the species Rumex acetosa. Simulations are performed to predict the form of the relative abundance distribution, and the dependence of the predicted number of coexisting genotypes on patch area (the genotype–area curve). We find that the predicted forms of the abundance distribution and genotype–area curve are indistinguishable from those measured at the species level. Furthermore, we identify the importance of physiological trade-offs at the individual level in promoting diversity and the sensitivity of genotype richness to the degree of similarity of individuals in the community. The extension of the model to include inter-species variation is discussed. [Copyright &y& Elsevier]