Exploratory multiscale analysis of the fish assemblages and habitats of the lower St. Lawrence River, Québec, Canada

Abstract

This work presents a multiscale analysis of the fish diversity of the lower St. Lawrence River which flows from the Laurentian Great Lakes of North America. A database of about 14,000 fish sampling stations from the lower St. Lawrence is linked to five different habitat maps of the study area: hydrographical units, water masses, depth, sediment type and wetland type. We hypothesize that species turnover (beta diversity) will be significant among these habitat maps. For each map, we calculate a UPGMA dendrogram based on the Jaccard coefficient of similarity in species occurrences as a first assemblage-habitat model. A randomization test is then used to identify the significant dendrograms from which we infer fish assemblages. We then show that many species are actually selecting or avoiding habitats. Finally, species selecting particular habitats are described by some selected ecological traits that are expected to occur frequently in those habitats. We found assemblages for the hydrographical units but not for the water masses. The fluvial section is selected by many stenohaline and some euryhaline species, while the freshwater estuary and the brackish estuary are only selected by euryhaline species. In the fluvial section at the hydrographical unit scale, many species associated with lentic habitats are limnophilic and more vegetation-dependent while many species selecting lotic habitats are rheophilic insectivorous species. Significant assemblages are defined for depth, sediment type and wetland type. Taken together, we found strong empirical evidence of a diverse actively selecting littoral assemblage of small, low mobility fishes opposing a channel assemblage of larger, more mobile fishes.

Longitudinal changes and indicator species of the fish fauna in the subtropical Sinos River, Brazil

“…Distribution of fish fauna is rarely caused by one factor (Horwitz, 1978; Angermeier et al , 2002). Despite the relevance of biotic interactions (Gilliam et al , 1993), fish fauna distribution is determined largely by micro‐habitat suitability (Ross et al , 1990; Matthews, 1986) and physiographic characteristics (Gorman & Karr, 1978; Felley & Felley, 1987; Rahel & Hubert, 1991; Leclerc & Desgranges, 2005; Robinson & Rand, 2005). Longitudinal distribution patterns of fish fauna were first described for mountain rivers in temperate regions, where abrupt changes in fauna composition were observed in relatively short distances (Huet, 1959; Sheldon, 1968; Matthews, 1986; Rahel & Hubert, 1991).…”

Challenges in developing fish‐based ecological assessment methods for large floodplain rivers

“…Fish communities gradually change along a river longitudinally (Huet 1954) and laterally to FWBs (e.g. Schiemer, Zalewski & Thorpe 1995; Navodaru, Buijse & Staras 2002; Leclerc & Desgranges 2005).…”

Functional characters combined with null models reveal inconsistency in mechanisms of species turnover in lacustrine fish communities

“…In particular, functional characters may act as indicators of the mechanisms that contribute to turnover in species composition between local communities (Jacquemyn et al 2005;Leclerc and DesGranges 2005;Stoks and McPeek 2003;Wellborn et al 1996), and of the processes that govern the co-occurrence of species within local communities (Armbruster et al 1994;Silvertown 2004;Stubbs and Wilson 2004). In this way, they may provide more detail on metacommunity processes than methods considering only species identity (e.g.…”