Fish nursery habitat function of the main channel, floodplain tributaries and oxbow lakes of a medium‐sized river

Abstract

Small, adventitious tributaries (<3 orders of magnitude smaller than the stream it flows into) are a conspicuous feature of many river–floodplain systems, but their value as fish reproduction and nursery habitat is not well understood compared to oxbow lakes and the main river channel (MRC). Moreover, connectivity of tributaries to the MRC is often less impacted by anthropogenic modifications (e.g., dams and levees) compared to oxbow lakes. From April to July 2012, larval and juvenile fish were collected in the Fourche LaFave River (Arkansas, USA) system to better understand fish nursery habitat function of tributaries relative to oxbow lakes and the MRC. Nonmetric multidimensional scaling ordination of juvenile and larval fish genera revealed distinct fish assemblages in MRC and floodplain habitats. Ordination of juvenile fish at the species level resulted in distinct fish assemblages in tributary versus oxbow lake habitats. Tributaries had more unique species and higher abundance of shared species than oxbow lakes and MRC. Additionally, of the 46 species identified, all but six were collected in lower tributary reaches. Connectivity was strongly associated with both ordinations and was important in describing patterns of fish variation among habitats and between tributaries. Of the tributaries sampled, the least fragmented stream had the most similar fish assemblages between upper and lower sections. Findings of this study revealed tributaries are an important, yet overlooked, feature in the river–floodplain model. Especially in years of drought, channel–floodplain connectivity can be limited, but tributaries can be used by fishes for reproduction and nursery habitat.

Mosaic environments shape the distribution of Neotropical freshwater ichthyoplankton

“…For example, a succession of rapids, waterfalls and lentic environments could increase mortality rate through damage from mechanical shock and decantation of eggs and yolk‐sac larvae (Corrêa et al, ). The lack of a floodplain also appears to reduce egg/larvae ratio because larvae tend to seek shelter in food‐abundant floodplains to complete development (Naus & Adams, ; Silva, Dias, & Bialetzki, ).…”

“…seek shelter in food-abundant floodplains to complete development (Naus & Adams, 2018;Silva, Dias, & Bialetzki, 2017).…”

Temporal and spatial dynamics of fish community structure during watershed alteration in two Ouachita River systems

“…For example, it was evident longitudinal structure was maintained among periods ( Figure 3). In addition, floodplain habitats and floodplain connectivity are important factors for reproduction of river-floodplain fishes (Copp, Oliver, Peňáz, & Roux, 1991;Naus & Adams, 2016). In addition, floodplain habitats and floodplain connectivity are important factors for reproduction of river-floodplain fishes (Copp, Oliver, Peňáz, & Roux, 1991;Naus & Adams, 2016).…”

“…Many fluvial specialists are dependent on high spring flow pulses for suitable spawning conditions that facilitate reproduction and recruitment (Ross & Baker, 1983;Turner, Krabbenhoft, & Burdett, 2010). In addition, floodplain habitats and floodplain connectivity are important factors for reproduction of river-floodplain fishes (Copp, Oliver, Peňáz, & Roux, 1991;Naus & Adams, 2016 it was generally only collected at the two most downstream sites during period one and period two. It was also evident pallid shiner (Hybopsis amnis) and weed shiner (Notropis texanus) were more abundant during period three, which have been shown to be dependent on specific flow regimes and hydrologic connectivity (Ross & Baker, 1983;Kwak, 1991;and Naus & Adams, 2016).…”

“…In addition, floodplain habitats and floodplain connectivity are important factors for reproduction of river-floodplain fishes (Copp, Oliver, Peňáz, & Roux, 1991;Naus & Adams, 2016 it was generally only collected at the two most downstream sites during period one and period two. It was also evident pallid shiner (Hybopsis amnis) and weed shiner (Notropis texanus) were more abundant during period three, which have been shown to be dependent on specific flow regimes and hydrologic connectivity (Ross & Baker, 1983;Kwak, 1991;and Naus & Adams, 2016). Although our study was temporal snapshots of multidecadal fish community dynamics and causal mechanisms were not determined, it appears natural flow regimes in the Saline River continue to play a role in population dynamics and persistence of species that require natural flow regimes and connectivity for upstream movement and floodplain access.…”