Modelling the hydraulic preferences of benthic macroinvertebrates in small European streams

Abstract

1. Relating processes occurring at a local scale to the natural variability of ecosystems at a larger scale requires the design of predictive models both to orientate stream management and to predict the effects of larger scale disturbances such as climate changes. Our study contributes to this effort by providing detailed models of the hydraulic preferences of 151 invertebrate taxa, mostly identified at the species level. We used an extensive data set comprising 580 invertebrate samples collected using a Surber net from nine sites of second and third order streams during one, two or three surveys at each site. We used nested nonlinear mixed models to relate taxon local densities to bed shear stresses estimated from FliesswasserStammTisch hemisphere numbers.2. An average model by taxon, i.e. independent from surveys, globally explained 25% of the density variations of taxa within surveys. A quadratic relationship existed between the average preferences and the niche breadth of taxa, indicating that taxa preferring extreme hemisphere numbers had a reduced hydraulic niche breadth. A more complete model, where taxa preferences vary across surveys, globally explained 38% of the variation of taxa densities within surveys. Variations in preferences across surveys were weak for taxa preferring extreme hemisphere numbers. 3. There was a significant taxonomic effect on preferences computed from the complete model. By contrast, season, site, average hemisphere number within a survey and average density of taxa within a survey used as covariates did not consistently explain shifts in taxon hydraulic preferences across surveys. 4. The average hydraulic preferences of taxa obtained from the extensive data set were well correlated to those obtained from two additional independent data sets collected in other regions. The consistency of taxon preferences across regions supports the use of regional preference curves for estimating the impact of river management on invertebrate communities. By contrast, the hydraulic niche breadths of taxa computed from the different data sets were not related.

Habitat variation at different scales and biotic linkages in lotic systems: consequences for monitorization

“…Results also showed that the WFD-based typology did not result in accurately segregated biological data. Dodkins et al (2007) encountered similar difficulties in adjusting biological variation to differently derived typologies (WFD system A, multivariate analyses, and expert opinion) and went on to outline a technique that optimized boundaries for the different communities and the selection of environmental variables similar to the DistLM procedure used in this study. Sánchez-Montoya et al (2007) showed that macroinvertebrate assemblage composition differed among three of four selected ecotypes and found significant differences between results from the bottom-up (from biological data) and top-down (from environmental data) classification approaches.…”

Microdistributions of stoneflies of the High Tatra montane streams

“…The result is a dynamic structure of morphological units (microhabitats), which form the basis of the structure and organization of biotic associations. The effects of flow on organisms can be expressed by the complex variable, shear stress [15]. Also, a correlation between average current velocity and hydraulic conditions near the substrate has been described [16], which indicates that average velocity has a significant relationship to conditions on the substratum and biota.…”

Biotic interactions enhance survival and fitness in the caddisfly Micropterna sequax (Trichoptera: Limnephilidae)

“…Current velocity was kept constant at 10 cm/s in all units and fell within the preferred flow preference range described for both species (Dolédec et al, 2007;de Brouwer et al, 2017). The water inside the units was constantly aerated and recirculated from a 600-L reservoir and consisted of preconditioned water (preconditioning time was 2 weeks, water consisted of a mixture of 550 L of tap water and 50 L of filtered water from a nearby stream).…”