Structure of small tropical island freshwater fish and crustacean communities: A niche‐or dispersal‐based process?

Type Article
Date 2021-01
Language English
Author(s) Lagarde Raphael1, 2, Teichert Nils3, Valade Pierre4, Ponton Dominique5
Affiliation(s) 1 : Centre de Formation et de Recherche sur les Environnements Méditerranéens UMR 5110 Université de Perpignan Via Domitia Perpignan ,France
2 : Centre de Formation et de Recherche sur les Environnements Méditerranéens UMR 5110 CNRS Perpignan ,France
3 : UMR 7208 BOREA (Biologie des Organismes et Ecosystèmes Aquatiques) Sorbonne Université MNHN CNRS UMPC Université Caen IRD – Station Marine de Dinard – CRESCO University of Antilles Guadeloupe ,France
4 : OCEA Consult’ La Réunion, France
5 : ENTROPIE IRD Université de La Réunion CNRS Université de la Nouvelle‐Calédonie – Ifremer
6 : Institut Halieutique et des Sciences Marines (IH.SM) Université de Toliara Toliara, Madagascar
Source Biotropica (0006-3606) (Wiley), 2021-01 , Vol. 53 , N. 1 , P. 243-254
DOI 10.1111/btp.12865
WOS© Times Cited 4
Keyword(s) abundances, diadromy, environmental gradients, migration, taxonomic richness, western Indian Ocean

Determining the relative importance of niche‐ and dispersal‐based processes in the structuring of animal communities is central in ecology. Freshwater fish and crustacean communities of small tropical islands can bring new insights for understanding these processes as all their species present a pelagic larval stage which gives them important dispersal capacities. Consequently, we hypothesized that dispersal‐based process may be preponderant for structuring these communities from the regional to the local, that is, survey site, scales. Gradient forest analyses allowed us to model the effect of 12 environmental variables on freshwater taxa abundances in two southwestern Indian Ocean islands: Mayotte (26 taxa) and Reunion (21). A total of 153 surveys in Mayotte and 266 in Reunion were used for building the models. Despite the strong heterogeneity of environmental conditions between the two islands, the main factors structuring freshwater fish and crustacean communities in both islands were the elevation and the slope of the sites. The observed structure appeared more pronounced for predatory species than for primary consumers and omnivores. As predators generally have limited locomotor capacities, it is concluded that dispersal‐based process structures these communities not only at large geographical scales but also at the intra‐watershed scale, by limiting the inland penetration (or dispersion) of species in relation to their locomotor capacities. However, more knowledge concerning ecological traits and taxonomic status of many species is needed to confirm this assumption.

Abstract in French is available with online material

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