Four major patterns identified through hierarchical clustering plotted by IPD ratio over time. Four major patterns identified through hierarchical clustering plotted by IPD ratio over time. Pattern A contains sites where the IPD ratio is stable from 8 to 16 h and then gradually increases over time. Pattern B contains sites where the IPD ratio generally declines from 24 to 72 h (with a subpopulation that increases at 48 h) and then increases up to 120 h. Pattern C contains sites where IPD ratios reach the highest value at 72 h and then decrease. Pattern D sites have the highest IPD ratios at 24 h with a subsequent increase after 72 h. Numbers in the bottom right-hand corner in each panel indicate the number of sites with each pattern (grey number in parentheses represents the grey subpopulation in pattern B). Lacey L. Westphal et al. mSystems 2016; doi:10.1128/mSystems.00130-16