Fine sediment reduces vertical migrations of Gammarus pulex (Crustacea: Amphipoda) in response to surface water loss

Surface and subsurface sediments in river ecosystems are recognized as refuges that may promote invertebrate survival during disturbances such as floods and streambed drying. Refuge use is spatiotemporally variable, with environmental factors including substrate composition, in particular the proportion of fine sediment (FS), affecting the ability of organisms to move through interstitial spaces. We conducted a laboratory experiment to examine the effects of FS on the movement of Gammarus pulex Linnaeus (Crustacea: Amphipoda) into subsurface sediments in response to surface water loss. We hypothesized that increasing volumes of FS would impede and ultimately prevent individuals from migrating into the sediments. To test this hypothesis, the proportion of FS (1–2 mm diameter) present within an open gravel matrix (4–16 mm diameter) was varied from 10 to 20% by volume in 2.5% increments. Under control conditions (0% FS), 93% of individuals moved into subsurface sediments as the water level was reduced. The proportion of individuals moving into the subsurface decreased to 74% at 10% FS, and at 20% FS no individuals entered the sediments, supporting our hypothesis. These results demonstrate the importance of reducing FS inputs into river ecosystems and restoring FS-clogged riverbeds, to promote refuge use during increasingly common instream disturbances

Small lakes in big landscape : multi-scale drivers of littoral ecosystem in alpine lakes.

In low nutrient alpine lakes, the littoral zone is the most productive part of the ecosystem, and it is a biodiversity hotspot. It is not entirely clear how the scale and physical heterogeneity of surrounding catchment, its ecological composition, and larger landscape gradients work together to sustain littoral communities. A total of 113 alpine lakes from the central Pyrenees were surveyed to evaluate the functional connectivity between littoral zoobenthos and landscape physical and ecological elements at geographical, catchment and local scales, and to ascertain how they affect the formation of littoral communities. At each lake, the zoobenthic composition was assessed together with geolocation, catchment hydrodynamics, geomorphology and topography, riparian vegetation composition, the presence of trout and frogs, water pH and conductivity. Multidimensional fuzzy set models integrating benthic biota and environmental variables revealed that at geographical scale, longitude unexpectedly surpassed altitude and latitude in its effect on littoral ecosystem. This reflects a sharp transition between Atlantic and Mediterranean climates and suggests a potentially high horizontal vulnerability to climate change. Topography (controlling catchment type, snow coverage and lakes connectivity) was the most influential catchment-scale driver, followed by hydrodynamics (waterbody size, type and volume of inflow/outflow). Locally, riparian plant composition significantly related to littoral community structure, richness and diversity. These variables, directly and indirectly, create habitats for aquatic and terrestrial stages of invertebrates, and control nutrient and water cycles. Three benthic associations characterised distinct lakes. Vertebrate predation, water conductivity and pH had no major influence on littoral taxa. This work provides exhaustive information from relatively pristine sites, and unveils a strong connection between littoral ecosystem and catchment heterogeneity at scales beyond the local environment. This underpins the role of alpine lakes as sensors of local and large-scale environmental changes, which can be used in monitoring networks to evaluate further impacts

Spatio-temporal patterns of fish assemblages in a large regulated alluvial river

1. The River Durance, the last alpine tributary of the River Rhone, is a large, braided alluvial hydrosystem. Following large-scale regulation, flow downstream of the Serre-Poncon dam has been maintained at 1⁄40th of previous annual mean discharge. To assess the effects of historical disturbances, fish assemblages and habitat use were analysed during five summers in a representative reach of the middle Durance. 2. Habitat availability and use were assessed with a multi-scale approach including the variables water depth, current velocity, roughness height of substratum, amount of woody debris and lateral⁄longitudinal location. Eighteen fish species were sampled by electrofishing in 289 habitat sample units. 3. Partial least square (PLS) regression showed that taxa were mainly distributed according to relationships between their total length and water depth⁄velocity variables. Fish assemblage composition was also related to roughness height as well as distance from the bank or to the nearest large woody debris. However, PLS regression revealed no significant differences in habitat selection between two periods of varying hydromorphological stability. 4. Fish distribution patterns and density were related to proximity to the bank and cover, indicating that local scale variables need to be considered in conservation and restoration programmes

Hydrological influences on aquatic communities at the mesohabitat scale in high Andean streams of southern Ecuador

[EN] This study assessed the effects of hydrological events on aquatic communities at the mesohabitat scale (pool, run, and riffle) in the high Andean region. Four headwater sites located in the Zhurucay microcatchment (southern Ecuador), with elevations higher than 3,500 m, were selected and monitored considering in each site a 50-m-long reach and within each reach five cross sections. In each of these reaches, 19 sampling campaigns were conducted in the period December 2011-October 2013, collecting macroinvertebrates and physical characteristics. A total of 27 hydrological indices were calculated using the daily flow rate as input. Large peak flow, small peak flow, and low flow (LF) events were defined based on discharge thresholds. Multivariate statistics showed that 14 hydrological indices were significantly related to the aquatic community. Further, the study revealed that (a) peak events produced stronger effects on communities than LF events, (b) the observed effects of LF events were weaker than those encountered in other latitudes, and (c) local benthic communities have more resilience than similar communities studied in other latitudes.The authors would like to express their gratitude to the research and technical staff of the Aquatic Ecology Laboratory (LEA) of the Universidad de Cuenca (UC, Ecuador) for assisting on the field data collection and posterior laboratory analyses and to project SENESCYT PIC-11-715 for providing some hydrological data. This study was performed in the scope of the research project SENESCYT PIC-11-726, directed and codirected, respectively, by the third and fourth authors, and financed by the Ecuadorian Secretary of Higher Education, Science, Technology and Innovation (SENESCYT), the National Electricity Corporation of Ecuador (CELEC EP-Hidropaute), and the Research Directory of the UC (DIUC). Further, financial support was provided by SENESCYT through a fellowship granted to the first author for carrying out his doctoral programme and through the PROMETEO fellowship awarded to the third author. The preparation of this manuscript is in line with the sabbatical leave programme of the fourth author and the development of the WATERMAS project cofunded by the Erasmus+ Programme of the European Union. The authors are grateful to Nuria Bonada and Jan Feyen for their helpful comments on the first draft of this manuscript.Vimos-Lojano, D.; Martinez-Capel, F.; Hampel, H.; Vázquez, RF. (2019). Hydrological influences on aquatic communities at the mesohabitat scale in high Andean streams of southern Ecuador. Ecohydrology. 12(1):1-17. https://doi.org/10.1002/eco.2033S117121Acosta, R., & Prat, N. (2010). Chironomid assemblages in high altitude streams of the Andean region of Peru. Fundamental and Applied Limnology / Archiv für Hydrobiologie, 177(1), 57-79. doi:10.1127/1863-9135/2010/0177-0057Angradi, T. R. (1997). Hydrologic Context and Macroinvertebrate Community Response to Floods in an Appalachian Headwater Stream. American Midland Naturalist, 138(2), 371. doi:10.2307/2426829Armanini, D. G., Idigoras Chaumel, A., Monk, W. A., Marty, J., Smokorowski, K., Power, M., & Baird, D. J. (2014). Benthic macroinvertebrate flow sensitivity as a tool to assess effects of hydropower related ramping activities in streams in Ontario (Canada). Ecological Indicators, 46, 466-476. doi:10.1016/j.ecolind.2014.07.018Armstrong, J. ., Kemp, P. ., Kennedy, G. J. ., Ladle, M., & Milner, N. . (2003). Habitat requirements of Atlantic salmon and brown trout in rivers and streams. Fisheries Research, 62(2), 143-170. doi:10.1016/s0165-7836(02)00160-1Barbero, M. D., Oberto, A. M., & Gualdoni, C. M. (2013). Spatial and temporal patterns of macroinvertebrates in drift and on substrate of a mountain stream (Cordoba, Central Argentina). Acta Limnologica Brasiliensia, 25(4), 375-386. doi:10.1590/s2179-975x2013000400003Belmar, O., Velasco, J., Gutiérrez-Cánovas, C., Mellado-Díaz, A., Millán, A., & Wood, P. J. (2012). The influence of natural flow regimes on macroinvertebrate assemblages in a semiarid Mediterranean basin. Ecohydrology, 6(3), 363-379. doi:10.1002/eco.1274Bispo, P. C., Oliveira, L. G., Bini, L. M., & Sousa, K. G. (2006). Ephemeroptera, Plecoptera and Trichoptera assemblages from riffles in mountain streams of Central Brazil: environmental factors influencing the distribution and abundance of immatures. 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Freshwater Biology, 57(3), 563-574. doi:10.1111/j.1365-2427.2011.02725.xDekar, M. P., & Magoulick, D. D. (2007). Factors affecting fish assemblage structure during seasonal stream drying. Ecology of Freshwater Fish, 16(3), 335-342. doi:10.1111/j.1600-0633.2006.00226.xDewson, Z. S., James, A. B. W., & Death, R. G. (2007). Invertebrate community responses to experimentally reduced discharge in small streams of different water quality. Journal of the North American Benthological Society, 26(4), 754-766. doi:10.1899/07-003r.1Durance, I., & Ormerod, S. J. (2010). Evidence for the role of climate in the local extinction of a cool-water triclad. Journal of the North American Benthological Society, 29(4), 1367-1378. doi:10.1899/09-159.1FLECKER, A. S., & FEIFAREK, B. (1994). Disturbance and the temporal variability of invertebrate assemblages in two Andean streams. Freshwater Biology, 31(2), 131-142. doi:10.1111/j.1365-2427.1994.tb00847.xFreeman, M. C., Bowen, Z. H., Bovee, K. D., & Irwin, E. 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MASKANA, 1(1), 91-100. doi:10.18537/mskn.01.01.07Alomía Herrera, I., & Carrera Burneo, P. (2017). Environmental flow assessment in Andean rivers of Ecuador, case study: Chanlud and El Labrado dams in the Machángara River. Ecohydrology & Hydrobiology, 17(2), 103-112. doi:10.1016/j.ecohyd.2017.01.002Holt, C. R., Pfitzer, D., Scalley, C., Caldwell, B. A., & Batzer, D. P. (2014). Macroinvertebrate Community Responses to Annual Flow Variation from River Regulation: An 11-Year Study. River Research and Applications, 31(7), 798-807. doi:10.1002/rra.2782Jacobsen, D., & Encalada, A. (1998). The macroinvertebrate fauna of Ecuadorian highland streams in the wet and dry season. Fundamental and Applied Limnology, 142(1), 53-70. doi:10.1127/archiv-hydrobiol/142/1998/53Jowett, I. G. (1993). A method for objectively identifying pool, run, and riffle habitats from physical measurements. New Zealand Journal of Marine and Freshwater Research, 27(2), 241-248. doi:10.1080/00288330.1993.9516563Lake, P. S. (2003). Ecological effects of perturbation by drought in flowing waters. Freshwater Biology, 48(7), 1161-1172. doi:10.1046/j.1365-2427.2003.01086.xLAM, P. K. S., & CALOW, P. (1988). DIFFERENCES IN THE SHELL SHAPE OF LYMNAEA PEREGRA (MÜLLER) (GASTROPODA: PULMONATA) FROM LOTIC AND LENTIC HABITATS; ENVIRONMENTAL OR GENETIC VARIANCE? Journal of Molluscan Studies, 54(2), 197-207. doi:10.1093/mollus/54.2.197Lamouroux, N., Dolédec, S., & Gayraud, S. (2004). Biological traits of stream macroinvertebrate communities: effects of microhabitat, reach, and basin filters. Journal of the North American Benthological Society, 23(3), 449-466. doi:10.1899/0887-3593(2004)0232.0.co;2Lancaster, J., & Hildrew, A. G. (1993). Flow Refugia and the Microdistribution of Lotic Macroinvertebrates. Journal of the North American Benthological Society, 12(4), 385-393. doi:10.2307/1467619LEDGER, M. E., EDWARDS, F. K., BROWN, L. E., MILNER, A. M., & WOODWARD, G. (2011). Impact of simulated drought on ecosystem biomass production: an experimental test in stream mesocosms. Global Change Biology, 17(7), 2288-2297. doi:10.1111/j.1365-2486.2011.02420.xLeigh, C. (2012). Dry-season changes in macroinvertebrate assemblages of highly seasonal rivers: responses to low flow, no flow and antecedent hydrology. Hydrobiologia, 703(1), 95-112. doi:10.1007/s10750-012-1347-yLima, A. C., Sayanda, D., Agostinho, C. S., Machado, A. L., Soares, A. M. V. M., & Monaghan, K. A. (2017). Using a trait-based approach to measure the impact of dam closure in fish communities of a Neotropical River. Ecology of Freshwater Fish, 27(1), 408-420. doi:10.1111/eff.12356Macnaughton, C. J., McLaughlin, F., Bourque, G., Senay, C., Lanthier, G., Harvey-Lavoie, S., … Boisclair, D. (2015). The Effects of Regional Hydrologic Alteration on Fish Community Structure in Regulated Rivers. River Research and Applications, 33(2), 249-257. doi:10.1002/rra.2991McElravy, E. P., & Resh, V. H. (1991). Distribution and seasonal occurrence of the hyporheic fauna in a northern California stream. Hydrobiologia, 220(3), 233-246. doi:10.1007/bf00006579McIntosh, M. D., Benbow, M. E., & Burky, A. J. (2002). Effects of stream diversion on riffle macroinvertebrate communities in a Maui, Hawaii, stream. River Research and Applications, 18(6), 569-581. doi:10.1002/rra.694Mesa, L. M. (2010). Effect of spates and land use on macroinvertebrate community in Neotropical Andean streams. Hydrobiologia, 641(1), 85-95. doi:10.1007/s10750-009-0059-4Mesa, L. M. (2012). Interannual and seasonal variability of macroinvertebrates in monsoonal climate streams. Brazilian Archives of Biology and Technology, 55(3), 403-410. doi:10.1590/s1516-89132012000300011Milhous , R. Bradley , J 1986 Physical habitat simulation and the moveable bedMilhous, R. T. (1998). Modelling of instream flow needs: the link between sediment and aquatic habitat. 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River Research and Applications, 22(5), 595-615. doi:10.1002/rra.933Mosquera, G. M., Lazo, P. X., Célleri, R., Wilcox, B. P., & Crespo, P. (2015). Runoff from tropical alpine grasslands increases with areal extent of wetlands. CATENA, 125, 120-128. doi:10.1016/j.catena.2014.10.010MOUTHON, J., & DAUFRESNE, M. (2006). Effects of the 2003 heatwave and climatic warming on mollusc communities of the Saone: a large lowland river and of its two main tributaries (France). Global Change Biology, 12(3), 441-449. doi:10.1111/j.1365-2486.2006.01095.xMoya, N., François-Marie, G., Oberdorff, T., Rosales, C., & Domínguez, E. (2009). COMPARACIÓN DE LAS COMUNIDADES DE MACROINVERTEBRADOS ACUÁTICOS EN RÍOS INTERMITENTES Y PERMANENTES DEL ALTIPLANO BOLIVIANO: IMPLICACIONES PARA EL FUTURO CAMBIO CLIMÁTICO. Ecología Aplicada, 8(1-2), 105. doi:10.21704/rea.v8i1-2.387Olsen, D. A., Hayes, J. W., Booker, D. J., & Barter, P. J. (2013). 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The hyporheic zone as an invertebrate refuge: a review of variability in space, time, taxa and behaviour

The hyporheic zone is a potential refuge that can promote persistence of benthic invertebrates during adverse conditions in surface streams. For decades, changes in invertebrate depth distribution have been investigated in relation to flood, low flow and drying events, but evidence for use of the hyporheic refuge remains equivocal. This review examines the evidence for the hyporheic zone’s refugial role during adverse hydrological conditions. Refuge potential is influenced by determinants in four categories. First, refuge use varies spatially in relation to physical habitat parameters, including sediment porosity and hydrologic exchange. Second, refuge use is temporally variable and reflects disturbance characteristics including rate of onset. Third, refuge use is taxon-specific, depending on a range of morphological, behavioural and physiological traits. Fourth, the behaviours governing refuge use vary, with both active migrations and passive habitat use playing important roles in community persistence. These four determinants interact to influence refuge use; for example, the physical habitat providing an adequate refuge will vary between taxa. Despite this variability, the hyporheic zone is an important component in the suite of refuges that facilitate community resilience to disturbance events. As such, its ecological integrity should be safeguarded through sensitive management and effective rehabilitation schemes

First record of Craspedacusta sowerbii Lankester, 1880 (Hydrozoa, Limnomedusae) in a natural freshwater lagoon of Uruguay, with notes on polyp stage in captivity

Abstract The freshwater cnidarian Craspedacusta sowerbii Lankester 1880, has invaded lakes and ponds as well as artificial water bodies throughout the world. The first record in Uruguay corresponding to the jellyfish was made in 1961 in two artificial fountains, with no mention of the polyp form. Although local reports of other related polyp species have been made, information on the benthic form of C. sowerbii is lacking. Here we report the finding of live frustules, solitary individuals, medusae and colonies from a natural lagoon in August 2010, allowing us to observe the morphology and behavior of the polyp stage in captivity. In addition, molecular identification and remarks on the potencial path of introduction are presented. This is the first record in Uruguay of both polyp and medusa stages of C. sowerbii in a natural water body, Del Medio Lagoon (Dpto. de Florida), Uruguay

Recent advances quantifying the large wood dynamics in river basins: New methods and remaining challenges

Citation: Ruiz-Villanueva, V., Piégay, H., Gurnell, A. A., Marston, R. A., & Stoffel, M. (2016). Recent advances quantifying the large wood dynamics in river basins: New methods and remaining challenges. Reviews of Geophysics. doi:10.1002/2015RG000514Large wood is an important physical component of woodland rivers and significantly influences river morphology. It is also a key component of stream ecosystems. However, large wood is also a source of risk for human activities as it may damage infrastructure, block river channels, and induce flooding. Therefore, the analysis and quantification of large wood and its mobility are crucial for understanding and managing wood in rivers. As the amount of large-wood-related studies by researchers, river managers, and stakeholders increases, documentation of commonly used and newly available techniques and their effectiveness has also become increasingly relevant as well. Important data and knowledge have been obtained from the application of very different approaches and have generated a significant body of valuable information representative of different environments. This review brings a comprehensive qualitative and quantitative summary of recent advances regarding the different processes involved in large wood dynamics in fluvial systems including wood budgeting and wood mechanics. First, some key definitions and concepts are introduced. Second, advances in quantifying large wood dynamics are reviewed; in particular, how measurements and modeling can be combined to integrate our understanding of how large wood moves through and is retained within river systems. Throughout, we present a quantitative and integrated meta-analysis compiled from different studies and geographical regions. Finally, we conclude by highlighting areas of particular research importance and their likely future trajectories, and we consider a particularly underresearched area so as to stress the future challenges for large wood research. ©2016. American Geophysical Union

PRELIMINARY TESTING OF A SELENIUM-BASED SYSTEMIC DEER BROWSE REPELLENT

Silviculturists use a variety of techniques, including repellents, to reduce browse damage by white-tailed deer (Odocoileus virginianus) to valuable eastern hardwood seedlings. Systemic selenium, sodium selenite, was evaluated with captive white-tailed deer for its repellency in white ash (Fraxinus americana) and black cherry (Prunus serotina) seedlings. Selenium had no effect in reducing browsing of black cherry. However, there was a reduction (p\u3c0.05) in the white ash browsing level

Inter-Habitat Variation in the Benthos of the Upper Missouri River (North Dakota, USA): Implications for Great River Bioassessment

We examined inter-habitat variation in benthic macroinvertebrate assemblages in the 180-km Garrison Reach of the Upper Missouri River, North Dakota (USA) in 2001–2003. The Garrison Reach is unchannelized with a mostly rural setting. Flows are regulated by Garrison Dam. We sampled benthos from three habitats defined a priori: channel, shoreline, and backwater. Benthic assemblages were different in each habitat. Average Bray-Curtis dissimilarity in assemblage composition ranged from 89% for backwater versus channel habitat to 70% for backwater versus shoreline habitat. There were distinct intra-habitat groups within a priori habitats: channel assemblages included moving-sand assemblages and other-substrate channel assemblages; backwater assemblages included connected (to the river channel) and unconnected backwater assemblages; shorelines assemblages varied between natural (unprotected) and riprap (rock revetment) shorelines. Abundance and taxa richness were lowest and spatial variability highest for moving-sand channel assemblages. Abundance was highest in backwaters. Taxa richness in backwaters and along channel shorelines were similar. Assemblages in all three habitats were dominated by Nematoda, Oligochaeta and Chironomidae. Taxa in these groups comprised at least 80% of mean abundance in all three habitats. Taxa that discriminated among habitats included the psammophilic chironomid Chernovskiia for moving-sand channel substrates versus all other habitats; Hydroptila (Trichoptera) for riprap vs natural shorelines, Aulodrilus (Oligochaeta) for connected versus unconnected backwaters; and Nematoda for backwater versus channel and shoreline versus channel. Based on overlap patterns in benthic assemblages among habitats, we concluded that sampling main channel shorelines should also capture much of the natural and stressor-induced variation in connected backwater and channel habitat exclusive of moving-sand channel habitat