Evolutionary causes and ecological consequences of mast seeding in plants

Mast seeding, the intermittent production of large seed crops by perennial plants, is an ecologically important phenomenon. For plants, masting interrupts reproduction and periodically depletes resources. For animals, masting causes temporal pulses in potentially nutritious food. Despite improved understanding of mast seeding in the 1990's, we only now have the tools to investigate several important avenues. First, the temporal and spatial scales. Secondly, the interaction between evolutionary benefits of masting (e.g., pollination efficiency) and the resource constraints operating within individual plants have not been explored. Third, to what extent do pulses in plant reproduction result in "ripple" effects through higher trophic levels? While direct effects on some organisms are known (e.g., small mammal densities may increase after mast years), indirect ecosystem-level effects are not well understood, especially whether ripples normally create stable (well-damped) or unstable ecosystem dynamics. These ripple effects are important to applied problems (e.g., forest pest outbreaks), and also for understanding the evolutionary origins of masting. Thus, we propose an interdisciplinary working group (plant evolutionary ecologists, animal population ecologists, community ecologists, modelers)that will use long term datasets on both seed crops and animal densities to formulate predictive models of the nature and consequences of mast seeding. The results will be important both to evolutionary theory and to understanding ecosystem functioning.