Paul undertakes scientific research and disseminates information through peer reviewed papers, reports, training, student supervision and other means. He has authored and co-authored >140 peer-reviewed papers (ISI h-score 44) and >10 books and book chapters. His research investigates the distribution and functioning of biodiversity, particularly through the novel integration and analysis of compiled data to understand large-scale and long-term processes, and their implications for the ways in which we understand and model systems. His work integrates research across levels of biological organization from viruses to chordates to elucidate scales, causes and consequences of variability in space and time.