Remotely-sensed slowing down in spatially patterned dryland ecosystems

bioRxiv (Cold Spring Harbor Laboratory)

Abstract

Abstract Regular vegetation patterns have been predicted to indicate a system slowing down and possibly desertification of drylands. However, these predictions have not yet been observed in dryland vegetation due to the inherent logistic difficulty to gather longer-term in situ data. Here, we use recently developed methods using remote-sensing EVI time-series in combination with classified regular vegetation patterns along a rainfall gradient in Sudan to test these predictions. Overall, three temporal indicators (responsiveness, temporal autocorrelation, variance) show slowing down as vegetation patterns change from gaps to labyrinths to spots towards more arid conditions, confirming predictions. However, this transition exhibits non-linearities, specifically when patterns change configuration. Model simulations reveal that the transition between patterns temporarily slows down the system affecting the temporal indicators. These transient states when vegetation patterns reorganize thus affect the systems resilience indicators in a non-linear way. Our findings suggest that spatial self-organization of dryland vegetation is associated with critical slowing down, but this transition towards reduced resilience happens in a non-linear way. Future work should aim to better understand transient dynamics in regular vegetation patterns in dryland ecosystems, because long transients make regular vegetation patterns of limited use for management in anticipating critical transitions.

Authors 4

1. Michiel P. Veldhuis corresponding Aachen Institute of Environmental Sciences (CML)

   Leiden University · University of Groningen · Princeton University

   Affiliation as printed

   Department of Ecology and Evolutionary Biology, Princeton University, Princeton, United States of America

   Groningen Institute for Evolutionary Life Sciences (GELIFES), University of Groningen, Groningen, The Netherlands

   Institute of Environmental Sciences (CML), Leiden University, Leiden, The Netherlands

2. Ricardo Martínez‐García

   Princeton University · ICTP South American Institute for Fundamental Research · Universidade Estadual Paulista (Unesp)

   Affiliation as printed

   Department of Ecology and Evolutionary Biology, Princeton University, Princeton, United States of America

   ICTP South American Institute for Fundamental Research & Instituto de Fisica Teorica, Universidade Estadual Paulista - UNESP, Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2 - Barra Funda, 01140-070 Sao Paulo, SP, Brazil

   ICTP South American Institute for Fundamental Research & Instituto de Fisica Teorica, Universidade Estadual Paulista - UNESP, Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2 - Barra Funda, 0110-070 Sao Paulo, SP, Brazil

3. Vincent Deblauwe

   University of California, Los Angeles · International Institute of Tropical Agriculture

   Affiliation as printed

   Center for Tropical Research, Institute of the Environment and Sustainability, University of California, Los Angeles, Los Angeles, CA 90095, USA

   International Institute of Tropical Agriculture, Yaound’e, Cameroon

   International Institute of Tropical Agriculture, Yaound'e, Cameroon

4. Vasilis Dakos

   Centre National de la Recherche Scientifique · École Pratique des Hautes Études · Université de Montpellier · Institut des Sciences de l'Evolution de Montpellier · Institut de Recherche pour le Développement

   Affiliation as printed

   Institut des Sciences de l’Evolution Montpellier, University of Montpellier/CNRS/EPHE/IRD, Montpellier, France

   Institut des Sciences de l'Evolution Montpellier, University of Montpellier/CNRS/EPHE/IRD, Montpellier, France