Unravelling large-scale patterns and drivers of biodiversity in dry rivers
Arnaud Foulquier, Thibault Datry, Roland Corti, Daniel von Schiller, Klement Tockner, Rachel Stubbington, Mark O. Gessner, Frédéric Boyer, Marc Ohlmann, Wilfried Thuiller, Delphine Rioux, Christian Miquel, Ricardo Albariño, Daniel C. Allen, Florian Altermatt, María Isabel Arce, Shai Arnon, Damien Banas, Andy Banegas‐Medina, Erin E. Beller, Melanie L. Blanchette, Joanna Blessing, Iola G. Boëchat, Kate S. Boersma, Michael T. Bogan, Núria Bonada, Nick Bond, Katherine Brintrup, Andreas Bruder, Ryan M. Burrows, Tommaso Cancellario, Cristina Canhoto, Stephanie M. Carlson, Núria Cid, Julien Cornut, Michaël Danger, Bianca de Freitas Terra, Anna Maria De Girolamo, Rubén del Campo, Verónica Díaz Villanueva, Fiona Dyer, Arturo Elosegi, Catherine Febria, Ricardo Figueroa, Brian Four, Sarig Gafny, Rosa Gómez, Lluís Gómez-Gener, Simone Guareschi, Björn Gücker, Jason L. Hwan, J. Iwan Jones, Patrick S. Kubheka, Alex Laini, Simone D. Langhans, B. Launay, Guillaume Le Goff, Catherine Leigh, Chelsea J. Little, Stefan Lorenz, Jonathan C. Marshall, Eduardo J. Martin Sanz, Angus R. McIntosh, Clara Mendoza‐Lera, Elisabeth I. Meyer, Marko Miliša, Musa C. Mlambo, Manuela Morais, Nabor Moya, Peter Negus, Dev Niyogi, Iluminada Pagán, Athina Papatheodoulou, Giuseppe Pappagallo, Isabel Pardo, Petr Pařil, Steffen U. Pauls, Marek Polášek, Pablo Rodríguez‐Lozano, Robert J. Rolls, Maria Mar Sánchez-Montoya, Ana Savić, Oleksandra Shumilova, Kandikere R. Sridhar, Alisha Steward, Amina Taleb, A. Uzan, Yefrin Valladares, Ross Vander Vorste, Nathan J. Waltham, Dominik Žák, Annamaria Zoppini
Abstract
More than half of the world’s rivers dry up periodically, but our understanding of the biological communities in dry riverbeds remains limited. Specifically, the roles of dispersal, environmental filtering and biotic interactions in driving biodiversity in dry rivers are poorly understood. Here, we conduct a large-scale coordinated survey of patterns and drivers of biodiversity in dry riverbeds. We focus on eight major taxa, including microorganisms, invertebrates and plants: Algae, Archaea, Bacteria, Fungi, Protozoa, Arthropods, Nematodes and Streptophyta. We use environmental DNA metabarcoding to assess biodiversity in dry sediments collected over a 1-year period from 84 non-perennial rivers across 19 countries on four continents. Both direct factors, such as nutrient and carbon availability, and indirect factors such as climate influence the local biodiversity of most taxa. Limited resource availability and prolonged dry phases favor oligotrophic microbial taxa. Co-variation among taxa, particularly Bacteria, Fungi, Algae and Protozoa, explain more spatial variation in community composition than dispersal or environmental gradients. This finding suggests that biotic interactions or unmeasured ecological and evolutionary factors may strongly influence communities during dry phases, altering biodiversity responses to global changes. Over half the world’s rivers dry periodically, yet little is known about the biological communities in dry riverbeds. This study examines biodiversity across 84 non-perennial rivers in 19 countries using DNA metabarcoding. It finds that nutrient availability, climate and biotic interactions influence the biodiversity of these dry environments.