Scientists’ limited understanding of tropical plant communities obscures the true extent of species loss caused by habitat destruction1. The Centinelan extinction hypothesis2,3 posits an extreme but widely referenced scenario wherein forest clearing causes the immediate extinction of species known only from a single geographic location. It remains unclear, however, whether the disappearance of such microendemics reflects their global extinction or insufficient collection effort at larger scales. Here we test these hypotheses by synthesizing decades of floristic data from the heavily deforested tropical cloud forest (TCF) at Centinela, Ecuador. We find that 99% of its putative microendemics have been collected elsewhere and are not extinct. Our field work also revealed new species, highlighting the enduring conservation value of TCFs and the intense efforts required to illuminate such plant diversity ‘darkspots’4. Field and herbarium research remain essential to the conservation action needed to forestall large-scale plant extinctions in Earth’s beleaguered cloud forests.
