With time comes diversity

This paper tests the mechanisms by which plant evolutionary radiations emerge and influence ecological dynamics with focus on 16 species-rich genera in the alpine zone of New Zealand. Occurrences from GBIF aided reconstruction of the niche space that each genus has occupied over the last 20 million years, along with ambitious steps like calculating sea-surface temperatures through the Cenozoic from isotopic measurements of foraminifera deposited in marine sediment cores, then using these to estimate past land temperatures. Their results suggest that genera that colonized New Zealand earlier encountered more ‘vacant’ environmental space, which promoted species diversification and further occupancy of the environment. Thus time not only explains why diversity arises, but how this diversity influences ecological dynamics.