Species occupancy and its course in the past: Macroecological patterns in extinct communities

Questions: What is the shape of occupancy trajectories in fossil organisms? And what is the effect of occupancy on species survival? Data studied: Occupancy and its course through time for a species in extinct large mammal communities from Italy. Search method: We tested if occupancy (the proportion of fossil sites representing a given paleocommunity where a species is present) patterns in extinct communities match a bimodal distribution as in living communities. Then we regressed occupancy on species duration to estimate its effect on long-term survival. We built a null model of random occupancy trajectories and compared it to real data. Conclusions: The occupancy-frequency distribution in extinct communities is either bimodal or right skewed. We found a positive relationship between high occupancy and species survival. We found peaked occupancy trajectories to be the norm for hoofed mammals at least. © 2006 Pasquale Raia.