Efficiency of Surber net under different substrate and flow conditions: insights for macroinvertebrates sampling and river biomonitoring

Doretto, Alberto; Bo, Tiziano; Bona, Francesca; Fenoglio, Stefano

doi:10.1051/kmae/2020001

Cited by 13 publications

(12 citation statements)

References 17 publications

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“…substrate type) occurrence. A Surber net (0.05 m 2 , 250 lm mesh-size) was placed flush with the river bottom, and benthic macroinvertebrates were collected by perturbing and washing the surface of substrate elements inside the metal frame of the net (Doretto et al 2020a). Benthic invertebrates were preserved in the field in 90% ethanol labelled jars, transported to the laboratory where samples were sorted and all individuals were counted and systematically identified to family level under a microscope (NIKON SMZ 1500 light microscope; 60-100 X), following the taxonomic keys for the Italian macroinvertebrate fauna (Campaioli et al 1994(Campaioli et al , 1999.…”

Section: Macroinvertebrate Samplingmentioning

confidence: 99%

Contribution of beta diversity in shaping stream macroinvertebrate communities among hydro-ecoregions

Bo¹,

Doretto

Levrino

et al. 2020

Aquat Ecol

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Rivers are heterogeneous and patchy-structured systems in which regional biodiversity of aquatic communities typically varies as a function of local habitat conditions and spatial gradients. Understanding which environmental and spatial constraints shape the diversity and composition of benthic communities is therefore a pivotal challenge for basic and applied research in river ecology. In this study, benthic invertebrates were collected from 27 sites across three hydro-ecoregions with the aim of investigating patterns in α- and β diversity. We first assessed the contribution to regional biodiversity of different and nested spatial scales, ranging from micro-habitat to hydro-ecoregion. Then, we tested differences in α diversity, taxonomic composition and ecological uniqueness among hydro-ecoregions. Variance partitioning analysis was used to evaluate the mechanistic effects of environmental and spatial variables on the composition of macroinvertebrate communities. Macroinvertebrate diversity was significantly affected by all the spatial scales, with a differential contribution according to the type of metric. Sampling site was the spatial scale that mostly contributed to the total richness, while the micro-habitat level explained the largest proportion of variance in Shannon–Wiener index. We found significant differences in the taxonomic composition, with 39 invertebrate families significantly associated with one or two hydro-ecoregions. However, effects of environmental and spatial controls were context dependent, indicating that the mechanisms that promote beta diversity probably differ among hydro-ecoregions. Evidence for species sorting, due to natural areas and stream order, was observed for macroinvertebrate communities in alpine streams, while spatial and land-use variables played a weak role in other geographical contexts.

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Section: Macroinvertebrate Samplingmentioning

confidence: 99%

Contribution of beta diversity in shaping stream macroinvertebrate communities among hydro-ecoregions

Bo¹,

Doretto

Levrino

et al. 2020

Aquat Ecol

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“…Datry et al, 2017;Samways et al, 2020) and considering that the overall pool of species in Alpine streams is expected to be mainly composed by taxa not adapted to drying (e.g. Doretto et al, 2018Doretto et al, , 2020aPiano et al, 2019a), we made the following hypotheses: (i) taxonomic diversity should decrease in intermittent sites at both reach and basin; (ii) variation in taxa composition among permanent and intermittent reaches is best explained by taxa loss (i.e., nestedness) than by taxa replacement (i.e. turnover); and (iii) loss of taxa displaying particular trait combinations should directly lead to a reduction of functional diversity and a general rearrangement of the total functional space.…”

Section: Introductionmentioning

confidence: 99%

“…Datry, Bonada, & Boulton, 2017; Samways et al., 2020) and considering that the overall pool of species in Alpine streams is expected to be mainly composed by taxa not adapted to drying (e.g. Doretto, Bo, Bona, & Fenoglio, 2020; Doretto et al., 2018; Piano, Doretto, Falasco, Fenoglio, et al, 2019), we made the following hypotheses: (1) taxonomic diversity should decrease in intermittent sites at both reach and basin scale; (2) variation in taxa composition among permanent and intermittent reaches is better explained by taxa loss (i.e. nestedness) in intermittent reaches than by taxa replacement (i.e.…”

Section: Introductionmentioning

confidence: 99%

Taxonomic and functional homogenisation of macroinvertebrate communities in recently intermittent Alpine watercourses

et al. 2020

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1. Mountain streams are currently shifting from perennial to intermittent regime due to the combined effect of climate change and local anthropogenic pressures. Studies on the effect of flow intermittency on macroinvertebrates are as yet inconclusive due to the large heterogeneity in geographical areas and spatial scales at which this relationship has been investigated. Given that flow intermittency is a recently documented phenomenon in the Alps, only few studies have investigated functional and taxonomical diversity of benthic invertebrate communities in recently intermittent Alpine streams. 2. We used a hierarchical sampling design to investigate patterns in taxonomic and functional diversity of benthic invertebrate communities in 13 recently intermittent Alpine streams in NW-Italy. In each of these streams, we sampled in April 2017 benthic communities in two reaches with different hydrological conditions: a control reach, with permanent flow, and an intermittent reach, which recently experienced non-flow periods in summer. 3. We tested for the response of taxonomic richness at multiple spatial scales by partitioning total diversity into the average richness of local communities and the richness due to variation among local communities both within and among reaches. By partitioning total diversity (γ) into its local (α) and turnover (β) components we showed a decrease in local and regional species richness both within and among reaches, whereas variation among communities was significantly lower in intermittent reaches only at the reach scale. 4. The analysis of the multidimensional trait space of macroinvertebrates in reaches with different hydrological conditions further revealed a significant reduction of functional diversity, dispersion, and evenness in intermittent reaches. There was trait overdispersion in intermittent reaches, as these hosted both typical Alpine taxa and organisms adapted to flow intermittency. In particular, we observed the replacement of taxa with aquatic respiration and preferring medium-to fastflowing oligotrophic waters by taxa adapted to lentic habitats and with larval dormancy phases. 5. These results provide strong support that recent flow intermittency determines drastic changes of benthic invertebrate communities in Alpine streams which are facing a "mediterraneization" process. Our work highlights the importance of considering multiple spatial scales and of integrating taxonomic and functional diversity to throughly assess the impacts of flow intermittency.

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“…In each patch, which consisted of a surface of 0.062 m 2 , i.e., the area of the Surber sampler, we measured flow velocity (0.05 m from the bottom) and water depth with a current meter (Hydro-bios Kiel) and we visually estimated percentages of different substratum sizes measured with a gravelometer following the classification of Wentworth, namely boulders ([ 256 mm), cobbles (64-256 mm), gravel (2-64 mm) and fine sediment (\ 2 mm). One sample was collected in each sampling patch, by using a Surber sampler (250 lm mesh size; 0.062 m 2 area) and we collected both the retained CPOM and macroinvertebrates (Doretto et al, 2020b). Collected samples were preserved in plastic jars with 75% ethanol.…”

Section: Sampling Designmentioning

confidence: 99%

Flow intermittency negatively affects three phylogenetically related shredder stoneflies by reducing CPOM availability in recently intermittent Alpine streams in SW-Italian Alps

et al. 2020

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Several Alpine streams are currently facing recurrent summer drying events with detrimental consequences on stream detritivores, i.e., shredders, due to negative effects via changes the organic matter (CPOM) availability. We examined the ecological requirements of three phylogenetically related shredder genera belonging to the family of Nemouridae (Plecoptera), namely Nemoura, Protonemura and Amphinemura, in 14 Alpine streams recently facing recurrent summer flow intermittency events. We evaluated the overlap among their ecological niches measured in terms of hydraulic stress, substrate composition, changes in CPOM availability and competition with other shredder taxa (i.e., presence of individuals of other shredders) and we examined potential changes in their ecological niches between permanent and intermittent sites. The ecological niches of Protonemura and Amphinemura overlap broadly, but not with Nemoura, suggesting only partial potential competition. The reduced CPOM availability decreased the individual abundance of the three genera in intermittent sites, where they consistently preferred microhabitats with high CPOM availability and low competition with other shredder taxa, possibly due to food limitation. Overall, our results emphasize how the negative effect of flow intermittency on shredders in Alpine streams is mainly due to the decrease in CPOM availability, with consequent potential bottom up effects on stream ecosystem functionality.

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Efficiency of Surber net under different substrate and flow conditions: insights for macroinvertebrates sampling and river biomonitoring

Cited by 13 publications

References 17 publications

Contribution of beta diversity in shaping stream macroinvertebrate communities among hydro-ecoregions

Contribution of beta diversity in shaping stream macroinvertebrate communities among hydro-ecoregions

Taxonomic and functional homogenisation of macroinvertebrate communities in recently intermittent Alpine watercourses

Flow intermittency negatively affects three phylogenetically related shredder stoneflies by reducing CPOM availability in recently intermittent Alpine streams in SW-Italian Alps

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