My research touches on a variety of themes including conservation prioritization, invasion ecology, biogeography and spatial statistics. I have a particular interest in practical questions regarding invasive species control and management to protect threatened species. My work in these areas aims to provide conservation agencies with useful tools that allow them to achieve better results within their limited budgets. I also look at theoretical questions regarding coexistence in fluctuating environments, methods for quantifying biodiversity, and the determinants of community assembly. My study systems include polar regions, temperate grasslands and lakes, and tropical forests.