The ecology and evolution of plant reproductive strategies

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Plant reproductive strategies influence gene transmission, population demography, and net rates of evolutionary diversification. Understanding the evolution and ecology of these strategies is key to understanding Darwin's 'abominable mystery' - the rapid diversification and rise to dominance of the flowering plants. The short-term goals of this proposal are to develop our understanding of the ecology and evolution of plant clonality and spatial segregation of the sexes. These two topics have languished without substantive developments in their conceptual underpinnings. Our understanding of plant clonality in particular needs revision; clonal plants are widespread and often ecologically dominant but studies of the ecological costs and benefits of clonality lag far behind that of other reproductive modes. For spatial segregation of the sexes (i.e., segregation between females and males within populations; a widespread feature of plants with separate sexes) there has been no theory and very little experimentation on how segregation affects reproductive fitness. The research proposed here aims to reset our understanding of these concepts via development of new theory and via tests of this theory using rigorous field experimentation in combination with molecular-genetic techniques. We ask: (i) can clonality promote reproductive fitness in comparison with non-clonal plants, contrary to widely-held views? and (ii) does spatial segregation have negative consequences for reproductive fitness, and are these consequences equal for females vs. males? In answering these questions, we will also be conducting some of the first direct tests of core evolutionary theory. Taken together, this proposal aims to transform our understanding of plant clonality and the segregation of female and male plants and to advance knowledge of fundamental, but rarely tested biological concepts. These short-term objectives contribute directly to the lab's long term goal of understanding the ecological processes regulating evolutionary transitions in plant reproductive strategy and thereby revealing processes that regulate flowering plant diversity.