Groundwater is a hidden global keystone ecosystem
Mattia Saccò, Stefano Mammola, Florian Altermatt, Roman Alther, Rossano Bolpagni, Anton Brancelj, Dávid Brankovits, Cene Fišer, Vasilis Gerovasileiou, Christian Griebler, Simone Guareschi, Grant C. Hose, Kathryn Korbel, Elisabeth Lictevout, Florian Malard, Alejandro Martínez, Matthew L. Niemiller, Anne L. Robertson, Krizler C. Tanalgo, Maria Elina Bichuette, Špela Borko, Traian Brad, Matthew A. Campbell, Pedro Cardoso, Fulvio Celico, Steven J. Cooper, David C. Culver, Tiziana Di Lorenzo, Diana M. P. Galassi, Michelle T. Guzik, Adam Hartland, William F. Humphreys, Rodrigo Lopes Ferreira, Enrico Lunghi, Daniele Nizzoli, Giulia Perina, Rajeev Raghavan, Zoe T. Richards, Аnа Sofiа P. S. Reboleirа, Melissa M. Rohde, David Sánchez‐Fernández, Susanne I. Schmidt, Mieke van der Heyde, Louise Weaver, Nicole E. White, Maja Zagmajster, Ian D. Hogg, Albert Ruhí, Marthe Monique Gagnon, Morten E. Allentoft, Robert Reinecke
Abstract
Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes. To foster timely global conservation of groundwater, we propose elevating the concept of keystone species into the realm of ecosystems, claiming groundwater as a keystone ecosystem that influences the integrity of many dependent ecosystems. Our global analysis shows that over half of land surface areas (52.6%) has a medium‐to‐high interaction with groundwater, reaching up to 74.9% when deserts and high mountains are excluded. We postulate that the intrinsic transboundary features of groundwater are critical for shifting perspectives towards more holistic approaches in aquatic ecology and beyond. Furthermore, we propose eight key themes to develop a science‐policy integrated groundwater conservation agenda. Given ecosystems above and below the ground intersect at many levels, considering groundwater as an essential component of planetary health is pivotal to reduce biodiversity loss and buffer against climate change.