Physical characteristics of the 18 streams.

<p>Mean values are presented along with standard deviations (SD). Letters indicate significant differences among stream types using one-way ANOVA and pair-wise Bonferroni corrected <i>post hoc</i> tests.</p><p>Physical characteristics of the 18 streams.</p

Macroinvertebrate community metrics in the three stream types.

<p>Mean values are presented along with standard deviations (SD).</p><p>Macroinvertebrate community metrics in the three stream types.</p

DCA ordination of macroinvertebrate communities in natural, channelized and restored stream reaches.

<p>Environmental parameters significantly (Spearman rank correlation, p<0.05) correlated with in-stream physical characteristics are also shown.</p

Location of the 18 stream reaches in Denmark.

<p>Natural streams (1–6); Restored streams (7–12); Channelized streams (13–18). UTM coordinates of the sites (UTM Zone 32, datum ED50). 1: Sunds Nørreå (N6231730; E496890), 2: Fjederholt (N6214415; E500939), 3: Linding (N6171439; E473283), 4: Gesager (N6190369; E543271), 5: Grydeå (N6243183; E471912), 6: Idom (N6243861; E468179), 7: Brøns (N6116409; E484998), 8: Lobæk (N6108125; E499423), 9: Surbæk (N6102701; E510372), 10: Jels (N6127631; E509606), 11: Gels (N6117435; E512790), 12: Lemming (N6233250; E532931), 13: Simmebæk (N6188424; E488854), 14: Fåre Mølleå (N6257940; E454624), 15: Madum (N6233919; E463860), 16: Hjortvad (N6137346; E494356), 17: Kongeå (N6141296; E519069), 18: Rejsby (N6121446; E483188).</p

Number of threatened species and abundance according to stream type.

<p>In total, 75 individuals of 9 threatened species were found in the 18 streams.</p

Relationship between stream bed sand coverage and substrate heterogeneity in the 3 stream types.

<p>The solid regression line describes the relationship in natural streams and the dotted line is the fitted line for channelized streams.</p

Relationship between substrate heterogeneity and macroinvertebrate community diversity for the 3 stream types.

<p>The solid regression line shows the significant relationship in natural streams.</p

Trait Characteristics Determine Pyrethroid Sensitivity in Nonstandard Test Species of Freshwater Macroinvertebrates: A Reality Check

We exposed 34 species of stream macroinvertebrates, representing 29 families, to a 90 min pulse of the pyrethroid λ-cyhalothrin. For 28 of these species, no pyrethroid ecotoxicity data exist. We recorded mortality rates 6 days post-exposure, and the behavioral response to pyrethroid exposure was recorded using automated video tracking. Most arthropod species showed mortality responses to the exposure concentrations (0.01–10 μg L^–1), whereas nonarthropod species remained unaffected. LC₅₀ varied by at least a factor of 1000 among arthropod species, even within the same family. This variation could not be predicted using ecotoxicity data from closely related species, nor using species-specific indicator values from traditional ecological quality indices. Moreover, LC₅₀ was not significantly correlated to effect thresholds for behavioral responses. Importantly, however, the measured surface area–weight ratio and the preference for coarse substrates significantly influenced the LC₅₀ for arthropod species, with the combination of small individuals and strong preference for coarse substrates indicating higher pyrethroid sensitivity. Our study highlights that existing pesticide ecotoxicity data should be extrapolated to untested species with caution and that actual body size (not maximum potential body size, as is usually available in traits databases) and habitat preference are central parameters determining species sensitivities to pyrethroids

Hering_etal_JAPPL_2015_Data

Abundance data of the organism groups and raw values of abiotic response variables investigated (e.g. habitat diversity). These values were used to calculate Bray-Curtis dissimilarity indices for the restored and respective degraded sites

The relationships between biotic uniqueness and abiotic uniqueness are context dependent across drainage basins worldwide

Context Global change, including land-use change and habitat degradation, has led to a decline in biodiversity, more so in freshwater than in terrestrial ecosystems. However, the research on freshwaters lags behind terrestrial and marine studies, highlighting the need for innovative approaches to comprehend freshwater biodiversity. Objectives We investigated patterns in the relationships between biotic uniqueness and abiotic environmental uniqueness in drainage basins worldwide. Methods We compiled high-quality data on aquatic insects (mayflies, stoneflies, and caddisflies at genus-level) from 42 drainage basins spanning four continents. Within each basin we calculated biotic uniqueness (local contribution to beta diversity, LCBD) of aquatic insect assemblages, and four types of abiotic uniqueness (local contribution to environmental heterogeneity, LCEH), categorized into upstream land cover, chemical soil properties, stream site landscape position, and climate. A mixed-effects meta-regression was performed across basins to examine variations in the strength of the LCBD-LCEH relationship in terms of latitude, human footprint, and major continental regions (the Americas versus Eurasia). Results On average, relationships between LCBD and LCEH were weak. However, the strength and direction of the relationship varied among the drainage basins. Latitude, human footprint index, or continental location did not explain significant variation in the strength of the LCBD-LCEH relationship. Conclusions We detected strong context dependence in the LCBD-LCEH relationship across the drainage basins. Varying environmental conditions and gradient lengths across drainage basins, land-use change, historical contingencies, and stochastic factors may explain these findings. This context dependence underscores the need for basin-specific management practices to protect the biodiversity of riverine systems.</p