The longstanding view of Neotropical mountain uplift as a promoter of species diversification has become commonplace in the last decades and could benefit from more specific Earth-Life evolution associations. We now know that mountain formation has contributed to the outstanding levels of richness and endemism of Neotropical mountains. Nonetheless, we are lacking conceptual and empirical frameworks where geological and biological processes are causally linked through testable hypotheses. In this perspective, we present volcanic activity in the Neotropics, not as phenomena occurring “on top of” mountain uplift, the latter being the phenomena of biogeographical interest, but rather as geological processes that directly impact biodiversity and are themselves the phenomenon of biogeographical interest. Volcanoes deserve biogeographical attention because their effects on landscape evolution generate predictable biodiversity process counterparts that can be integrated into biogeographical models enabling hypothesis testing. We review examples in the literature emphasizing the spatio-temporal scale of volcanism’s predicted and recorded effects on biodiversity. We illustrate our perspective by two recent study cases, focusing on wax palms and passerine birds. In the first one, wax palm genomic sampling was used to test 2 hypotheses: that the northern Andes have been disconnected in the past and connected by rapid but repeated eruptions of caldera-forming eruptions in the Colombian Massif fostering episodic dispersal, or alternatively, that they have always been continuous and have gradually uplifted hosting continuous diversification and dispersal through time. In broadly this same area, genetic and phenotypic data revealed the existence of a hybrid zone between species in the warbler genus Myioborus. Because hybridization is likely younger than volcanic activity, topographic connection spurred by volcanism could have also enabled secondary contact between previously isolated species, a hypothesis that merits formal testing. Altogether, we emphasize the pertinence of the volcanic record in offering opportunities for the evaluation of biogeographical hypotheses in the context of Neotropical mountains and their singularly outsized biodiversity.
