A global analysis of terrestrial plant litter dynamics in non-perennial waterways

T. Datry (1) , A. Foulquier (2) , R. Corti (3) , D. von Schiller (4) , K. Tockner (3) , C. Mendoza-Lera , Jean-Christophe Clement (5) , C. Clement , O. Gessner , M. Moleón , R. Stubbington , B. Gücker , R. Albariño , C. Allen (6) , F. Altermatt , M. Arce (7) , S. Arnon , D. Banas (8) , A. Banegas-Medina , E. Beller , M. Blanchette , J. Blanco-Libreros , J. Blessing , I. Boëchat , K. Boersma , M. Bogan , N. Bonada (9) , N. Bond , C. Brintrup Barría , A. Bruder , R. Burrows , T. Cancellario , C. Canhoto , M. Carlson , S. Cauvy-Fraunié , N. Cid , M. Danger (10) , Bianca de Freitas Terra , A. de Girolamo , Evans de La Barra , R. del Campo , D. Diaz-Villanueva , F. Dyer , A. Elosegi (11) , E. Faye , C. Febria , B. Four , S. Gafny , D. Ghate , R. Gómez , L. Gómez-Gener , A. Graça , S. Guareschi , F. Hoppeler , J. Hwan , I. Jones , S. Kubheka , A. Laini , D. Langhans , C. Leigh (12) , C. Little , S. Lorenz , C. Marshall , E. Martin (13) , A. Mcintosh , I. Meyer , M. Miliša , C. Mlambo , M. Morais (14) , N. Moya , M. Negus , D. Niyogi (15) , A. Papatheodoulou , I. Pardo (16) , P. Pařil , S. Pauls (17) , V. Pešić , M. Polášek , C. Robinson , P. Rodríguez-Lozano , R. Rolls , M. Sánchez-Montoya , A. Savić , O. Shumilova , R. Sridhar (18) , A. Steward , R. Storey , Ahmed Taleb , A. Uzan , Ross Vander Vorste (1) , N. Waltham , C. Woelfle-Erskine , D. Zak , C. Zarfl , A. Zoppini

1 UR MALY - Milieux aquatiques, écologie et pollutions
2 LECA - Laboratoire d'Ecologie Alpine
3 IGB - Leibniz-Institut für Gewässerökologie und Binnenfischerei
4 UPV/EHU - Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne]
5 CARRTEL - Centre Alpin de Recherche sur les Réseaux Trophiques et Ecosystèmes Limniques
6 SoGE - School of Geography and the Environment [Oxford]
7 IIPG - Instituto de Investigación en Paleobiología y Geología [Río Negro]
8 URAFPA - Unité de Recherches Animal et Fonctionnalités des Produits Animaux
9 Institut de Recerca de la Biodiversitat (IRBio)
10 LIEC - Laboratoire Interdisciplinaire des Environnements Continentaux
11 Department of Plant Biology and Ecology
12 ICSL - Intelligent Control Systems Laboratory
13 Conseil Général du Rhône
14 SIMaP - Science et Ingénierie des Matériaux et Procédés
15 Purdue University [West Lafayette]
16 Centro de investigaciones biológicas
17 Klinik für Diagnostische und Interventionelle Radiologie
18 Department of Biosciences [Mangalore]

Perennial rivers and streams make a disproportionate contribution to global carbon (C) cycling. However, the contribution of intermittent rivers and ephemeral streams (IRES), which sometimes cease to flow and can dry completely, is largely ignored although they represent over half the global river network. Substantial amounts of terrestrial plant litter (TPL) accumulate in dry riverbeds and, upon rewetting, this material can undergo rapid microbial processing. We present the results of a global research collaboration that collected and analysed TPL from 212 dry riverbeds across major environmental gradients and climate zones. We assessed litter decomposability by quantifying the litter carbon-to-nitrogen ratio and oxygen (O2) consumption in standardized assays and estimated the potential short-term CO2 emissions during rewetting events. Aridity, cover of riparian vegetation, channel width and dry-phase duration explained most variability in the quantity and decomposability of plant litter in IRES. Our estimates indicate that a single pulse of CO2 emission upon litter rewetting contributes up to 10% of the daily CO2 emission from perennial rivers and stream, particularly in temperate climates. This indicates that the contributions of IRES should be included in global C-cycling assessments.

Mots clés: GLOBAL CHANGE

Mots clés: TEMPORARY RIVERS; CYCLE DU CARBONE; RIVER ECOSYSTEM FUNCTIONING; CO2 EMISSIONS; C CYCLE

Mots clés: LITIÈRE VÉGÉTALE; CHANGEMENT CLIMATIQUE; COURS D'EAU; VÉGÉTATION RIPICOLE

Mots clés: ZONE CLIMATIQUE; RIPARIAN VEGETATION

Domaines: Sciences de l'environnement; Milieux et Changements globaux; Interfaces continentales, environnement

T. Datry, A. Foulquier, R. Corti, D. von Schiller, K. Tockner, et al.. A global analysis of terrestrial plant litter dynamics in non-perennial waterways. Nature Geoscience, 2018, 11 (7), pp.497-503. ⟨10.1038/s41561-018-0134-4⟩. ⟨hal-01802266⟩