Metapopulation persistence and species spread in river networks |
| |
Authors: | Lorenzo Mari Renato Casagrandi Enrico Bertuzzo Andrea Rinaldo Marino Gatto |
| |
Affiliation: | 1. Dipartimento di Elettronica, Informazione e Bioingegneria, Politecnico di Milano, , 20133 Milano, Italy;2. Laboratory of Ecohydrology ECHO/IIE/ENAC, école Polytechnique Fédérale de Lausanne, , 1015 Lausanne, Switzerland;3. Dipartimento di Ingegneria Civile, Edile ed Ambientale, Università di Padova, , 35131, Padova, Italy |
| |
Abstract: | River networks define ecological corridors characterised by unidirectional streamflow, which may impose downstream drift to aquatic organisms or affect their movement. Animals and plants manage to persist in riverine ecosystems, though, which in fact harbour high biological diversity. Here, we study metapopulation persistence in river networks analysing stage‐structured populations that exploit different dispersal pathways, both along‐stream and overland. Using stability analysis, we derive a novel criterion for metapopulation persistence in arbitrarily complex landscapes described as spatial networks. We show how dendritic geometry and overland dispersal can promote population persistence, and that their synergism provides an explanation of the so‐called `drift paradox’. We also study the geography of the initial spread of a species and place it in the context of biological invasions. Applications concerning the persistence of stream salamanders in the Shenandoah river, and the spread of two invasive species in the Mississippi‐Missouri are also discussed. |
| |
Keywords: | Bifurcations dominant eigenvalue ecohydrology extinction debt fluvial systems metapopulation capacity movement ecology topology |
|
|