The rise of angiosperms pushed conifers to decline during global cooling (Proc. Natl. Acad. Sci. USA)

During the Triassic and Jurassic periods (approximately 250 – 140 million years ago), Earth was dominated by gymnosperms including conifers. Today, the number of species and individuals is greatly reduced from their heyday, and instead Earth is dominated by angiosperms. Although it is widely stated that angiosperms outcompeted gymnosperms and pushed them to the harsher high-altitude and high-latitude regions, this idea has not been rigorously proven. Now, Condamine et al. have used a “paleoenvironment-dependent diversification model (PDDM) applied to both the conifer phylogeny and the fossil record”. Their data rule out the hypothesis that a mass extinction event such as one caused by climate change led to the decline in conifers. Instead, they show that the accelerated rate of extinction of conifers was most likely caused by direct competition by angiosperms, compounded with the effect of global cooling. (Summary by Mary Williams @PlantTeaching) Proc. Natl. Acad. Sci. USA 10.1073/pnas.2005571117