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Olivier Dangles - One of the best experts on this subject based on the ideXlab platform.
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temporal scaling of high flow effects on Benthic Fauna insights from equatorial glacier fed streams
Limnology and Oceanography, 2015Co-Authors: Sophie Cauvyfraunie, Patricio Andino, Rodrigo Espinosa, Dean Jacobsen, Olivier DanglesAbstract:We used equatorial glacier-fed streams as a model system to investigate the relationships between flow fluctuation and Benthic Fauna at different temporal scales. Water level was measured at 30 min intervals over 29 months (942 d) and Benthic macroinvertebrates were sampled 14 times over the study period. We performed wavelet analyses on water-level time series to identify temporal scales at which significant flow variation occurs, and calculated three indices: intensity, frequency and temporal clustering of the diurnal flow variation for periods from 2 d to 50 d. We determined the effect of temporal scaling (length of the periods considered) on relationships between Benthic community dissimilarity (using Sorensen index) and differences in flow indices among the 14 sampling dates. Temporal scaling affected flow-variation frequency and temporal clustering and their subsequent relationships with Benthic community dissimilarity. A time scale of 15 d before Benthic sampling was relevant to the assessment of flow-biota relationships. Community dissimilarity significantly increased with increasing difference in flow-fluctuation intensity. This dissimilarity was associated with a decrease in the density of dominant taxa and a taxa turnover along the temporal gradient in flow-fluctuation intensity. Although flow fluctuations are frequent and highly predictable in equatorial glacier-fed streams, macroinvertebrate communities exhibited a temporal variability in taxon assemblage, which was linked to the intensity of flow fluctuation. We explain these patterns by downstream displacement during high flow events and upstream displacement during low flow periods, thereby highlighting the need of considering temporal scaling effects on Benthic Fauna to understand the ecological dynamics of lotic systems.
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glacial flood pulse effects on Benthic Fauna in equatorial high andean streams
Hydrological Processes, 2013Co-Authors: Sophie Cauvyfraunie, Patricio Andino, Rodrigo Espinosa, Dean Jacobsen, Olivier Dangles, Roger Calvez, Fabien AnthelmeAbstract:Equatorial glacier-fed streams present unique hydraulic patterns when compared to glacier-fed observed in temperate regions as the main variability in discharge occurs on a daily basis. To assess how Benthic Fauna respond to these specific hydraulic conditions, we investigated the relationships between flow regime, hydraulic conditions (boundary Reynolds number, Re*), and macroinvertebrate communities (taxon richness and abundance) in a tropical glacier-fed stream located in the high Ecuadorian Andes (> 4000 m). Both physical and biotic variables were measured under four discharge conditions (base-flow and glacial flood pulses of various intensities), at 30 random points, in two sites whose hydraulic conditions were representative to those found in other streams of the study catchment. While daily glacial flood pulses significantly increased hydraulic stress in the Benthic habitats (appearance of Re* > 2000), low stress areas still persisted even during extreme flood events (Re* < 500). In contrast to previous research in temperate glacier-fed streams, taxon richness and abundance were not significantly affected by changes in hydraulic conditions induced by daily glacial flood pulses. However, we found that a few rare taxa, in particular rare ones, preferentially occurred in highly stressed hydraulic habitats. Monte-Carlo simulations of Benthic communities under glacial flood reduction scenarios predicted that taxon richness would be significantly reduced by the loss of high hydraulic stress habitats following glacier shrinking. This pioneer study on the relationship between hydraulic conditions and Benthic diversity in an equatorial glacial stream evidenced unknown effects of climate change on singular yet endangered aquatic systems. Copyright © 2013 John Wiley & Sons, Ltd.
Rutger Rosenberg - One of the best experts on this subject based on the ideXlab platform.
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reducing spatial variation in environmental assessment of marine Benthic Fauna
Marine Pollution Bulletin, 2016Co-Authors: Kjell Leonardsson, Mats Blomqvist, Rutger RosenbergAbstract:The Benthic Quality Index, BQI, is widely used for Benthic quality assessment. Here, we investigated if spatial variation in the BQI can be reduced by accounting for the environmental factors instead of having different boundaries for different salinity regimes between status classes in the EU Water Framework Directive and Marine Strategy Framework Directive. For this purpose we tested salinity, sediment structure, and depth in a regression model to test their contribution to variations in BQI. The spatial variation in BQI was better explained by depth than by salinity or sediment structure. The proposed assessment method uses the residuals from the regression model between BQI and depth. With this method the variance in BQI between samples was reduced by 50% to 75% in the majority of situations. A method to establish the boundary between good and moderate status and how to derive EQR-values according to the WFD is presented.
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importance of functional biodiversity and species specific traits of Benthic Fauna for ecosystem functions in marine sediment
Marine Ecology Progress Series, 2007Co-Authors: Karl Norling, Rutger Rosenberg, Stefan Hulth, Antoine Gremare, Erik BonsdorffAbstract:Fauna have been found to regulate important biogeochemical properties and ecosystem functions in Benthic environments. In this study, we focused on how functional biodiversity and species-specific traits of Benthic macroFauna affect key ecosystem functions related to organic matter mineralization and cycling of nutrients in surface sediments. Dominant Benthic invertebrates from the Baltic Sea and the Skagerrak were classified into functional groups in accordance with their behaviour, feeding and sediment reworking activities. MacroFauna species were added in different combinations to deFaunated Baltic sediments in 2 parallel microcosm systems fuelled with brackish and marine water. In total, there were 12 treatments that differed in terms of functional diversity of Benthic Fauna. The experiments demonstrated that Faunal activities directly affected Benthic oxygen and nutrient fluxes, sediment reactivity and pore-water distribution under both Baltic and Skagerrak conditions. Benthic fluxes, sediment reactivity and pore-water distribution were similar in Baltic and Skagerrak treatments, in which the same functional biodiversity and species-specific traits of Benthic macroFauna were observed. Although no significant effects of functional biodiversity could be detected under Baltic or Skagerrak conditions, treatments with bioturbating Fauna from the Skager- rak enhanced oxygen consumption and nutrient fluxes compared to treatments with Baltic Fauna and Skagerrak Fauna with functional groups similar (parallel) to the Baltic Fauna. Moreover, species- specific traits related to the Skagerrak Fauna (e.g. the thalassinid shrimp Calocaris macandreae) exceeded the effects of all other Faunal treatments. This suggests that species-specific traits of macro- Fauna may override species richness and functional biodiversity of macroFauna when regulating important ecosystem properties and functions in Benthic environments.
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recovery of marine Benthic habitats and Fauna in a swedish fjord following improved oxygen conditions
Marine Ecology Progress Series, 2002Co-Authors: Rutger Rosenberg, Stefan Agrenius, Birthe Hellman, Hans C Nilsson, Karl NorlingAbstract:The Gullmarsfjord on the Swedish west coast has a sill at 40 m and a maximum depth of 118 m. The stagnant bottom water is usually renewed with oxygen-rich water each spring. In 1997 this did not occur, and the Fauna was eliminated at depths below about 100 m and severely reduced between 80 and 100 m depth. In spring 1998, the whole fjord was re-oxygenated and the succession of the Benthic Fauna was studied at 5 stations over a 2 yr period. Simultaneously, the Benthic habitat quality (BHQ) was assessed by analysing sediment redox conditions and Faunal burrow structures in sediment profile images. Succession of the Benthic Fauna is described as increases in number of spe- cies, abundance and biomass. Conspicuous colonisers below 100 m depth were the polychaete Capitella capitata and the heart urchins Echinocardium cordatum and E. flavescens. Return to pre- oxygen stressed conditions was slowest at the deepest stations. By using a multivariate technique (multi-dimensional scaling) we show that the Benthic communities at all depths more or less returned to the same Faunal composition as during pre-disturbed conditions. The pioneering and mature ben- thic Faunal Successional Stages I and III were predictable but not the intermediate Stage II. The path of recovery of the Benthic community succession did not retrace the path of degradation. The sedi- mentary habitats and redox conditions were similarly restored over the 2 yr period as analysed by the BHQ index.
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temporal and spatial large scale effects of eutrophication and oxygen deficiency on Benthic Fauna in scandinavian and baltic waters a review
Oceanography and Marine Biology, 2002Co-Authors: Karin Karlson, Rutger Rosenberg, Erik BonsdorffAbstract:Eutrophication has been an increasing ecological threat during the past 50 yr in many Scandinavian and Baltic marine waters. Large sedimentary areas are seasonally, or more or less permanently, affected by hypoxia and/or anoxia with devastating effects on the Benthic macroFauna in, for example, the Baltic Sea, the Belt Seas and Oresund between Denmark and Sweden, the Kattegat and the Skagerrak coast towards the North Sea. In this review figures for the input of nitrogen and phosphorus to different sea areas are presented, and in several cases also changes of nitrogen and phosphorus concentrations in the water. The nutrient input is related to production levels, and related to macroBenthic inFauna. Changes of dominant Benthic species, abundance and biomass are presented in relation to both changes in organic enrichment and hypoxia and/or anoxia in time and space. Since the 1950s-60s, the Benthic Faunal biomass has increased in the Gulf of Bothnia as a result of increased organic enrichment. In the Aland Archipelago, the number of Benthic species decreased since the 1970s but abundance and biomass increased. Drifting algae at the sediment surface has also been an increasing problem. The changes were caused by increasing eutrophication. In the Finnish Archipelago Sea, large-scale eutrophication has resulted in periodic bottom water hypoxia and drifting algal mats with negative effects on Benthic Fauna. In the Gulf of Finland, the Benthic Fauna has been negatively affected by hypoxic bottom water below 70 in depth since the 1960s, but with a period of improved oxygen conditions during 1987-94. In the Baltic Proper, large sea-bed areas of 70 000-100 000 km(2) below 70-80 in water depth have been more or less hypoxic and/or anoxic since the 1960s with no or reduced sediment-dwelling Fauna. This process was a result of increased eutrophication and lack of larger inflows of oxygenated water from the Kattegat. Several coastal areas and larger basins in the southern Baltic (e.g. the Bornholm Basin, the Arkona Basin and the Kiel Bay), have, on occasions, been similarly negatively affected by hypoxic bottom water. Many sedimentary areas below similar to 17 in in the Danish Belt Seas have been affected by seasonal hypoxia since the 1970s with negative consequences for the bottom Fauna. On the Danish Kattegat coast, the Benthic Fauna in the Limfjord, the Mariager fjord and the Roskilde fjord have been particularly negatively affected. In the southeast, open Kattegat, increased input of nutrients in combination with stratification have resulted in seasonal hypoxia since 1980 with negative effects on Benthic animals and commercial fish species in most years. Several fjords on the Swedish and Norwegian Skagerrak coast have shown negative temporal trends in bottom water oxygen concentrations, and some of them lack Benthic Fauna in the deeper parts for several months or more. In this review the temporal development of bottom water hypoxia and/or anoxia is discussed and consequent possible losses of sediment-dwelling Faunal biomass are roughly calculated. In total for the areas investigated, the worst years of hypoxia and/or anoxia combined may have reduced the Benthic macroFaunal biomass by 3 million t. This loss is partly compensated by the biomass increase that has occurred in well-flushed organically enriched coastal areas. Tolerance of some Baltic species to hypoxia and/or anoxia is discussed and also their different strategies to cope with hypoxia and/or anoxia and H2S.
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response of Benthic Fauna and changing sediment redox profiles over a hypoxic gradient
Estuarine Coastal and Shelf Science, 2001Co-Authors: Rutger Rosenberg, Hans C Nilsson, Robert J DiazAbstract:The Koljofjord is an enclosed, stratified fjord on the Swedish west coast with hypoxic/anoxic bottom water during most of the year. In the winter 1999/2000, the water in the entire fjord was re-oxygenated after a period of stagnation, but the following summer oxygen concentrations declined to below 1 ml l−1between 20 and 40 m depths. The objectives of this study were to investigate the structure of Benthic communities along a depth gradient of declining oxygen concentrations and the impact of Fauna on sediment redox conditions. The vertical distribution of the Fauna in the sediment was restricted to the upper few centimetres. Dominant species at most stations were the burrower Capitella capitata and the tube-builder Pseudopolydora antennata. The species found in the fjord are probably not particularly tolerant towards hypoxia, but they have life-history traits that facilitate a rapid colonization following improved oxygen conditions. The depth of the Redox potential discontinuity (RPD) layer, a recognizable division zone between oxidized (sub-oxic) and reduced chemical conditions, is dependent on inFaunal activity, e.g. burrows, tubes and feeding voids. Measurement of apparent RPD (aRPD) from sediment profile images (SPIs) compared well to electrode measurement of RPD. We conclude that a digital analysis of aRPD from images has many advantages compared to RPD measurements by electrodes.
Erik Bonsdorff - One of the best experts on this subject based on the ideXlab platform.
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Hypoxia in the Baltic Sea: Biogeochemical cycles, Benthic Fauna, and management
Ambio, 2014Co-Authors: Jurgen Carstensen, Susanna Hietanen, Urzsula Janas, Tom Jilbert, Alexey Maximov, Bo G. Gustafsson, Erik Bonsdorff, Alf Norkko, Daniel J Conley, Joanna NorkkoAbstract:Hypoxia has occurred intermittently over the Holocene in the Baltic Sea, but the recent expansion from less than 10 000 km(2) before 1950 to >60 000 km(2) since 2000 is mainly caused by enhanced nutrient inputs from land and atmosphere. With worsening hypoxia, the role of sediments changes from nitrogen removal to nitrogen release as ammonium. At present, denitrification in the water column and sediments is equally important. Phosphorus is currently buried in sediments mainly in organic form, with an additional contribution of reduced Fe-phosphate minerals in the deep anoxic basins. Upon the transition to oxic conditions, a significant proportion of the organic phosphorus will be remineralized, with the phosphorus then being bound to iron oxides. This iron-oxide bound phosphorus is readily released to the water column upon the onset of hypoxia again. Important ecosystems services carried out by the Benthic Fauna, including biogeochemical feedback-loops and biomass production, are also lost with hypoxia. The results provide quantitative knowledge of nutrient release and recycling processes under various environmental conditions in support of decision support tools underlying the Baltic Sea Action Plan.
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importance of functional biodiversity and species specific traits of Benthic Fauna for ecosystem functions in marine sediment
Marine Ecology Progress Series, 2007Co-Authors: Karl Norling, Rutger Rosenberg, Stefan Hulth, Antoine Gremare, Erik BonsdorffAbstract:Fauna have been found to regulate important biogeochemical properties and ecosystem functions in Benthic environments. In this study, we focused on how functional biodiversity and species-specific traits of Benthic macroFauna affect key ecosystem functions related to organic matter mineralization and cycling of nutrients in surface sediments. Dominant Benthic invertebrates from the Baltic Sea and the Skagerrak were classified into functional groups in accordance with their behaviour, feeding and sediment reworking activities. MacroFauna species were added in different combinations to deFaunated Baltic sediments in 2 parallel microcosm systems fuelled with brackish and marine water. In total, there were 12 treatments that differed in terms of functional diversity of Benthic Fauna. The experiments demonstrated that Faunal activities directly affected Benthic oxygen and nutrient fluxes, sediment reactivity and pore-water distribution under both Baltic and Skagerrak conditions. Benthic fluxes, sediment reactivity and pore-water distribution were similar in Baltic and Skagerrak treatments, in which the same functional biodiversity and species-specific traits of Benthic macroFauna were observed. Although no significant effects of functional biodiversity could be detected under Baltic or Skagerrak conditions, treatments with bioturbating Fauna from the Skager- rak enhanced oxygen consumption and nutrient fluxes compared to treatments with Baltic Fauna and Skagerrak Fauna with functional groups similar (parallel) to the Baltic Fauna. Moreover, species- specific traits related to the Skagerrak Fauna (e.g. the thalassinid shrimp Calocaris macandreae) exceeded the effects of all other Faunal treatments. This suggests that species-specific traits of macro- Fauna may override species richness and functional biodiversity of macroFauna when regulating important ecosystem properties and functions in Benthic environments.
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temporal and spatial large scale effects of eutrophication and oxygen deficiency on Benthic Fauna in scandinavian and baltic waters a review
Oceanography and Marine Biology, 2002Co-Authors: Karin Karlson, Rutger Rosenberg, Erik BonsdorffAbstract:Eutrophication has been an increasing ecological threat during the past 50 yr in many Scandinavian and Baltic marine waters. Large sedimentary areas are seasonally, or more or less permanently, affected by hypoxia and/or anoxia with devastating effects on the Benthic macroFauna in, for example, the Baltic Sea, the Belt Seas and Oresund between Denmark and Sweden, the Kattegat and the Skagerrak coast towards the North Sea. In this review figures for the input of nitrogen and phosphorus to different sea areas are presented, and in several cases also changes of nitrogen and phosphorus concentrations in the water. The nutrient input is related to production levels, and related to macroBenthic inFauna. Changes of dominant Benthic species, abundance and biomass are presented in relation to both changes in organic enrichment and hypoxia and/or anoxia in time and space. Since the 1950s-60s, the Benthic Faunal biomass has increased in the Gulf of Bothnia as a result of increased organic enrichment. In the Aland Archipelago, the number of Benthic species decreased since the 1970s but abundance and biomass increased. Drifting algae at the sediment surface has also been an increasing problem. The changes were caused by increasing eutrophication. In the Finnish Archipelago Sea, large-scale eutrophication has resulted in periodic bottom water hypoxia and drifting algal mats with negative effects on Benthic Fauna. In the Gulf of Finland, the Benthic Fauna has been negatively affected by hypoxic bottom water below 70 in depth since the 1960s, but with a period of improved oxygen conditions during 1987-94. In the Baltic Proper, large sea-bed areas of 70 000-100 000 km(2) below 70-80 in water depth have been more or less hypoxic and/or anoxic since the 1960s with no or reduced sediment-dwelling Fauna. This process was a result of increased eutrophication and lack of larger inflows of oxygenated water from the Kattegat. Several coastal areas and larger basins in the southern Baltic (e.g. the Bornholm Basin, the Arkona Basin and the Kiel Bay), have, on occasions, been similarly negatively affected by hypoxic bottom water. Many sedimentary areas below similar to 17 in in the Danish Belt Seas have been affected by seasonal hypoxia since the 1970s with negative consequences for the bottom Fauna. On the Danish Kattegat coast, the Benthic Fauna in the Limfjord, the Mariager fjord and the Roskilde fjord have been particularly negatively affected. In the southeast, open Kattegat, increased input of nutrients in combination with stratification have resulted in seasonal hypoxia since 1980 with negative effects on Benthic animals and commercial fish species in most years. Several fjords on the Swedish and Norwegian Skagerrak coast have shown negative temporal trends in bottom water oxygen concentrations, and some of them lack Benthic Fauna in the deeper parts for several months or more. In this review the temporal development of bottom water hypoxia and/or anoxia is discussed and consequent possible losses of sediment-dwelling Faunal biomass are roughly calculated. In total for the areas investigated, the worst years of hypoxia and/or anoxia combined may have reduced the Benthic macroFaunal biomass by 3 million t. This loss is partly compensated by the biomass increase that has occurred in well-flushed organically enriched coastal areas. Tolerance of some Baltic species to hypoxia and/or anoxia is discussed and also their different strategies to cope with hypoxia and/or anoxia and H2S.
Claudio Richter - One of the best experts on this subject based on the ideXlab platform.
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Benthic Fauna declined on a whitening antarctic continental shelf
Nature Communications, 2020Co-Authors: Santiago E A Pinedametz, Dieter Gerdes, Claudio RichterAbstract:Ice retreat in West Antarctica and Antarctic Peninsula has led to important changes in seafloor communities and gains in Benthic blue carbon. In most of the Antarctic, however, sea ice increased between the 1970s and 2014, but its effects on the benthos remain largely unexplored. Here, we provide a 1988–2014 record of macro- and megaFauna from the north-eastern Weddell Sea shelf, where Benthic biomass decreased by two thirds and composition shifted from suspension feeders to deposit feeders. Concomitant increases in sea-ice cover suggest a reduced flux of primary production to the benthos. As Benthic communities are major repositories for Antarctic biodiversity and play an important role in biogeochemical cycling, the observed changes have far-reaching consequences for the Antarctic ecosystem and its feedback to the climate system. The findings underscore the importance of long-term ecological monitoring in a region vulnerable to warming and ice-shelf collapse. Sea-ice cover in Antarctica has increased over the last decades and reached a maximum in 2014. Here, the authors report strong declines in zooBenthic biomass and abundance and changes in community composition on the NE Weddell Sea shelf over 26 years, with implications for blue carbon and biochemistry in a globally important marine region.
Sophie Cauvyfraunie - One of the best experts on this subject based on the ideXlab platform.
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temporal scaling of high flow effects on Benthic Fauna insights from equatorial glacier fed streams
Limnology and Oceanography, 2015Co-Authors: Sophie Cauvyfraunie, Patricio Andino, Rodrigo Espinosa, Dean Jacobsen, Olivier DanglesAbstract:We used equatorial glacier-fed streams as a model system to investigate the relationships between flow fluctuation and Benthic Fauna at different temporal scales. Water level was measured at 30 min intervals over 29 months (942 d) and Benthic macroinvertebrates were sampled 14 times over the study period. We performed wavelet analyses on water-level time series to identify temporal scales at which significant flow variation occurs, and calculated three indices: intensity, frequency and temporal clustering of the diurnal flow variation for periods from 2 d to 50 d. We determined the effect of temporal scaling (length of the periods considered) on relationships between Benthic community dissimilarity (using Sorensen index) and differences in flow indices among the 14 sampling dates. Temporal scaling affected flow-variation frequency and temporal clustering and their subsequent relationships with Benthic community dissimilarity. A time scale of 15 d before Benthic sampling was relevant to the assessment of flow-biota relationships. Community dissimilarity significantly increased with increasing difference in flow-fluctuation intensity. This dissimilarity was associated with a decrease in the density of dominant taxa and a taxa turnover along the temporal gradient in flow-fluctuation intensity. Although flow fluctuations are frequent and highly predictable in equatorial glacier-fed streams, macroinvertebrate communities exhibited a temporal variability in taxon assemblage, which was linked to the intensity of flow fluctuation. We explain these patterns by downstream displacement during high flow events and upstream displacement during low flow periods, thereby highlighting the need of considering temporal scaling effects on Benthic Fauna to understand the ecological dynamics of lotic systems.
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glacial flood pulse effects on Benthic Fauna in equatorial high andean streams
Hydrological Processes, 2013Co-Authors: Sophie Cauvyfraunie, Patricio Andino, Rodrigo Espinosa, Dean Jacobsen, Olivier Dangles, Roger Calvez, Fabien AnthelmeAbstract:Equatorial glacier-fed streams present unique hydraulic patterns when compared to glacier-fed observed in temperate regions as the main variability in discharge occurs on a daily basis. To assess how Benthic Fauna respond to these specific hydraulic conditions, we investigated the relationships between flow regime, hydraulic conditions (boundary Reynolds number, Re*), and macroinvertebrate communities (taxon richness and abundance) in a tropical glacier-fed stream located in the high Ecuadorian Andes (> 4000 m). Both physical and biotic variables were measured under four discharge conditions (base-flow and glacial flood pulses of various intensities), at 30 random points, in two sites whose hydraulic conditions were representative to those found in other streams of the study catchment. While daily glacial flood pulses significantly increased hydraulic stress in the Benthic habitats (appearance of Re* > 2000), low stress areas still persisted even during extreme flood events (Re* < 500). In contrast to previous research in temperate glacier-fed streams, taxon richness and abundance were not significantly affected by changes in hydraulic conditions induced by daily glacial flood pulses. However, we found that a few rare taxa, in particular rare ones, preferentially occurred in highly stressed hydraulic habitats. Monte-Carlo simulations of Benthic communities under glacial flood reduction scenarios predicted that taxon richness would be significantly reduced by the loss of high hydraulic stress habitats following glacier shrinking. This pioneer study on the relationship between hydraulic conditions and Benthic diversity in an equatorial glacial stream evidenced unknown effects of climate change on singular yet endangered aquatic systems. Copyright © 2013 John Wiley & Sons, Ltd.