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J R Britton - One of the best experts on this subject based on the ideXlab platform.
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Genetic and phenotypic displacement of an endemic barbus complex by invasive European barbel barbus barbus in central Italy
Biological Invasions, 2020Co-Authors: Serena Zaccara, J R Britton, Antonella Carosi, Silvia Quadroni, Vanessa Santis, Isabella Vanetti, Giuseppe Crosa, Massimo LorenzoniAbstract:Invasions of alien fishes can result in considerable consequences for native biodiversity, including local extinctions of native species through genetic introgression. In Italy, the alien European barbel barbus barbus was first detected in 1994. It has since undergone range expansion, raising conservation concerns on their impacts on endemic barbus species, including barbus plebejus and barbus tyberinus . Here, the genetic and phenotypic consequences of B. barbus invasion in the Tyrrhenian and Adriatic basins of central Italy were assessed by comparing ‘invaded’ with ‘uninvaded’ river sections that remain free of B. barbus due to barriers preventing their upstream dispersal. In both basins, uninvaded sites were confirmed as B. barbus free, but the endemic populations had low genetic variability. In the invaded sections, haplotype and nucleotide diversity was relatively high, with introgression skewed towards B. barbus genes, with the barbel populations comprising of only 4% and 23% of pure B. tyberinus and B. plebejus respectively. Relatively high morphological differentiation was apparent between pure B. tyberinus and hybrid forms, whilst differences were less apparent between pure B. plebejus and their hybrid forms. Thus, the endemic barbus species only persist in areas that remain free of invasive B. barbus , with this only due to river structures that impede their upstream movements. As these structures also limit the effective population size of the endemic species, conservation plans must reconcile B. barbus dispersal prevention with the need to increase the population connectivity of the endemics.
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Spawning strategies in cypriniform fishes in a lowland river invaded by non-indigenous European barbel barbus barbus
Hydrobiologia, 2020Co-Authors: Catherine Gutmann Roberts, J R BrittonAbstract:Spawning strategies of lowland river fishes include single spawning, where reproduction generally occurs in early spring to provide 0+ fish with an extended growth season through the summer, but with a high risk of stochastic mortality events occurring, such as early summer floods. This risk can be reduced by multiple or protracted spawning strategies, where 0+ fish are produced over an extended period, often into mid-summer, but with the trade-off being a shorter growth season. The spawning strategies of cypriniform fish were explored in the River Teme, a spate river in Western England, which has non-indigenous European barbel barbus barbus present. Sampling 0+ fish in spring and summer and across three spawning periods, B. barbus , chub Squalius cephalus and minnow Phoxinus phoxinus always revealed multiple spawning events, with 0+ fish of < 20 mm present in samples collected from June to August. Fish below 20 mm in August remained relatively small by the end of their growth season (October). For dace Leuciscus leuciscus , only single spawning events were evident, but with 0+ dace always being relatively large. Therefore, multiple spawning appears to be a common strategy that provides resilience in 0+ fish against stochastic mortality events in lowland rivers.
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Factors influencing individual movements and behaviours of invasive European barbel barbus barbus in a regulated river
Hydrobiologia, 2019Co-Authors: Catherine Gutmann Roberts, Andrew M. Hindes, J R BrittonAbstract:Riverine fish are often adversely affected by impoundments that reduce longitudinal connectivity and impede movements, while river fishery performance is often enhanced by introductions of non-indigenous fishes that diversify angling opportunities. The influence of factors (including impoundment) on the movements of European barbel barbus barbus, a fish frequently introduced for angling, was tested in the continuous reach of the lower River Teme and Severn, western England. Following capture by electric fishing and angling, the movements of 18 fish were followed for 12 months using acoustic telemetry. Weirs at the upstream end of both river reaches impeded fish movements; only three fish traversed the Teme weir and no fish traversed the Severn weir. Net movements were mainly upstream in spring and downstream in autumn, and the daily movements of fish were asynchronous between individuals. Total (home) ranges varied considerably between individuals; those of fish initially captured by angling were significantly smaller than those captured by electric fishing. This potentially relates to fish with smaller total ranges being more vulnerable to angling via higher spatial encounters. The results reveal considerable individual variation in the movement of B. barbus and emphasises how river regulation can impact the dispersal and behaviour of river fishes.
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Quantifying the habitat and zoogeomorphic capabilities of spawning European barbel barbus barbus, a lithophilous cyprinid
2019Co-Authors: Gutmann C Roberts, J R Britton, T Bašić, Stephen Rice, Andrew PledgerAbstract:© 2019 The Authors. River Research and Applications published by Wiley Periodicals, Inc. Suitable gravel availability is critical for the spawning success of lithophilous fishes, including redd builders. Redd construction during spawning can alter substrate characteristics, thereby influencing hydraulic conditions and sediment transport, highlighting the importance of spawning as a zoogeomorphic activity. Here, interactions between redd-building fish and their spawning environment were investigated for European barbel barbus barbus with a comparative approach across three English rivers: Teme (western), Great Ouse (eastern) and Idle (central). Sediment characteristics of spawning habitats were similar across the rivers, including subsurface fine sediment (
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Tissue-specific turnover rates of the nitrogen stable isotope as functions of time and growth in a cyprinid fish
Hydrobiologia, 2018Co-Authors: Georgina M. A. Busst, J R BrittonAbstract:Ecological applications of stable isotope data require knowledge on the isotopic turnover rate of tissues, usually described as the isotopic half-life in days ( T _0.5) or the change in mass ( G _0.5). Ecological studies increasingly analyse tissues collected non-destructively, such as fish fin and scales, but there is limited knowledge on their turnover rates. Determining turnover rates in situ is challenging, with ex situ approaches preferred. Correspondingly, T _0.5 and G _0.5 of the nitrogen stable isotope (δ^15N) were determined for juvenile barbel barbus barbus (5.5 ± 0.6 g starting weight) using a diet-switch experiment. δ^15N data from muscle, fin and scales were taken during a 125 day post diet-switch period. Whilst isotopic equilibrium was not reached in the 125 days, the δ^15N values did approach those of the new diet. The fastest turnover rates were in more metabolically active tissues, from muscle (highest) to scales (lowest). Turnover rates were relatively slow; T _0.5 was 84 (muscle) to 145 (scale) days; G _0.5 was 1.39 × body mass (muscle) to 2.0 × body mass (scales), with this potentially relating to the slow growth of the experimental fish. These turnover estimates across the different tissues emphasise the importance of estimating half-lives for focal taxa at species and tissue levels for ecological studies.
Patrick Berrebi - One of the best experts on this subject based on the ideXlab platform.
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Rare and asymmetrical hybridization of the endemic barbus carpathicus with its widespread congener barbus barbus
Journal of Fish Biology, 2009Co-Authors: Z. Lajbner, Patrick Berrebi, V. Slechtova, V. Slechta, M. Svatora, Petr KotlikAbstract:In endemic species that co-occur with widespread congeners, hybridization can lead to an influx of novel and beneficial genetic variation, but high rates of introgression may cause genetic swamping of the endemic species and have detrimental effects on its survival potential. This study examines hybridization between sympatric populations of the Carpathian barbel barbus carpathicus, a recently discovered cryptic species with a restricted range, and the widespread common barbel barbus barbus. Based on six diagnostic allozyme loci, a microsatellite locus and mtDNA, hybrids were found to be present at multiple localities within the Vistula River drainage (Baltic Sea) as well as in the Tisza River system of the Danube River drainage (Black Sea). However, the numbers of hybrids were very low; four individuals of 230 fish sampled from the Vistula drainage. Bayesian assessment of their nuclear genotypes suggested that two hybrids in the Vistula drainage and nine in the Tisza system were F-1 generation, and one in the Vistula drainage and one in the Tisza system were backcrosses (BC) to B. barbus, while no F-2 or BC to B. carpathicus were detected. No hybrid carried B. carpathicus mtDNA and cytonuclear linkage disequilibria showed significant positive associations between hybrid genotypes and B. barbus mtDNA, suggesting unidirectionality in the interspecific mating with a disproportionate contribution of B. barbus mothers. Despite geographically broad occurrence of hybrids, these data provide evidence of strong constraints on hybridization in the native breeding habitats and the lack of introgression towards B. carpathicus.
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Nested Clade Phylogeographical Analysis of Barbel (barbus barbus) Mitochondrial DNA Variation
2007Co-Authors: Petr Kotlik, Patrick BerrebiAbstract:We aplied nested clade phylogeographical analysis (NCPA) to the mitochondrial DNA phylogeographical data of the Barbel barbus barbus to assess the historical biogeography scenario suggested fot this species by a traditional phylogeographical approach. Major previously inferred historical events received support from the NCPA: i) twofold range fragmentation, an ancient one between the Central European and Balkan/Anatolian populations and a more recent one ascribed to the survival of the central european lineage in two refugia during the latest glacial, and ii) contiguous range expansion from the danubian refuge into the more northwestern river basins. Likely due to insufficient genetic variation, the hypothesized dispersion from the more western central Europe refuge was not detected by the NCPA as was not the hypothesized expansion throughout the Balkans and Anatolia. The NCPA interpretation of the significant pattern within the Danube river basin as reflecting a recurrent gene flow restricted through isolation by distance should be taken with caution. Similar patterns can reflect non-equilibrium conditions, such as population growth, which seems a plausible alternative interpretation given the star-like genealogy of the danubian population, and its presumably short period of demographic stability.
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Autosomal differences between males and females in hybrid zones: a first report from barbus barbus and barbus meridionalis (Cyprinidae)
Heredity, 2004Co-Authors: A. Chenuil, L. Crespin, L. Pouyaud, Patrick BerrebiAbstract:Narrow hybrid zones are generally subjected to the action of two forces: dispersal, which tends to homogenise the hybridising taxa, and selection against hybrids, which, in contrast, produces steep clines of introgression for diagnostic markers. Although differences between sexes in dispersal abilities or in susceptibility to hybrid counterselection are common in hybrid zones, autosomal genetic differences between males and females have never been reported to our knowledge. barbus barbus and barbus meridionalis (Cyprinidae) form a hybrid zone along the Lergue river. By carrying out a genetic analysis of males and females in six samples from two central stations of the hybrid zone using codominant markers (six allozymes and four microsatellite loci), we revealed significant multilocus and monolocus differences between the sexes. This could reflect a genetic difference among sexes within a same cohort, caused either by a survival (or fertility) differential among sexes or by a sex-specific pattern of dispersal. Alternatively, this may be due to genetic differentiation between cohorts, since male and female barbel exhibit different maturation, growth and survival patterns leading to different age distributions among sexes, and particularly among reproducers.
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Spatially varying natural selection in a fish hybrid zone
Journal of Fish Biology, 2002Co-Authors: L. Crespin, Patrick Berrebi, Jean-dominique LebretonAbstract:A capture-mark-recapture (CMR) study in a hybrid zone between two species of barbel. barbus barbus and barbus meridionalis, in the Lergue (southern France) failed to reject the null hypothesis of no difference in survival among phenotypes. Power calculations indicated that very intensive fieldwork should be carried out if this hypothesis was to be investigated again. The study demonstrated, however, that there Acre marked differences in survival between upstream and downstream sites. It is suggested that there is an environmental gradient of selection along the hybrid zone (extrinsic component of natural selection).
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Phylogeography of the barbel (barbus barbus) assessed by mitochondrial DNA variation
Molecular Ecology, 2001Co-Authors: Petr Kotlik, Patrick BerrebiAbstract:Using the phylogeographic framework, we assessed the DNA sequence variation at the mitochondrial cytochrome b gene across the distribution range of the barbel barbus barbus, a widely distributed European cyprinid. Reciprocal monophyly of non-Mediterranean European and Balkan/Anatolian populations is taken as evidence for a long-term barrier to gene flow, and interpreted as a consequence of survival of the species in two separate refugia during several later glacial cycles. Lack of profound genealogical divergence across Europe from western France to the northwestern Black Sea basin is consistent with recent colonization of this area from a single glacial refuge, which was probably located in the Danube River basin. This may have occurred in two steps: into the Western European river basins during the last interglacial, and throughout the Central European river basins after the last glacial. The populations from the Balkans and Anatolia apparently did not contribute mitochondrial DNA to the post-Pleistocene colonization of non-Mediterranean Europe. Lack of detectable variation within the Balkans/Anatolia is attributed mainly to recent expansion throughout these regions, facilitated by the freshwater conditions and seashore regression in the Black Sea during the Late Pleistocene and Early Holocene.
Lorenzo Vilizzi - One of the best experts on this subject based on the ideXlab platform.
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Predation by invasive signal crayfish on early life stages of European barbel may be limited
Aquatic Conservation-marine and Freshwater Ecosystems, 2017Co-Authors: Gordon H Copp, Adam Ellis, M. J. Godard, Lorenzo Vilizzi, W D RileyAbstract:To determine whether or not signal crayfish Pacifastacus leniusculus and native white-clawed crayfish Austropotamobius pallipes prey on European barbel barbus barbus eggs, interstitial free-embryos and emergent larvae, experiments were undertaken in salmonid (substratum) incubators (six treatments, four controls) fitted with video recorders. No corpses or remains of emergent barbel larvae or eggs, or parts thereof, were observed in any of the incubators containing buried eggs, and no emergent larvae showed any sign of attack. However, video evidence of a signal crayfish catching and consuming a barbel larva was obtained. There were no statistically significant differences between white-clawed and signal crayfish either in carapace length or weight at the beginning and end of the experiments. The conservation implications of these results are discussed.
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an analysis of 0 barbel barbus barbus response to discharge fluctuations in a flume
River Research and Applications, 2005Co-Authors: Lorenzo Vilizzi, Gordon H CoppAbstract:We studied the response in velocity use and time in refuge of 0+ juvenile barbel (barbus barbus) to an increase in discharge in a flume. Each of five treated and five control fish were observed individually in separate eight-hour experiments. Observations (trials) were arranged into a hierarchically structured, semi-randomized sampling schedule consisting of four time levels: phase (4 h) ⊃ period (2 h) ⊃ sub-period (30 min) ⊃ trial (120 s). Increased discharge caused treated barbel to use higher velocities than control individuals, with individual differences in behaviour present at the various temporal tiers. Individual responses were modelled as either random-walk or short-memory processes, and those by treated fish were generally abrupt and permanent, with only one individual showing a gradual and permanent use of the higher velocities. Time in refuge was not affected by increased discharge, except for one fish that sought shelter after intervention. There was a significant relationship for most treated individuals between selection of lower velocities and time in refuge, and most barbel (both treated and control) showed significant deviations of used from mean flume velocities. The potential of the proposed approach to assess memory-based individual fish responses to discharge and its consequences for (PHABSIM-oriented) behavioural studies is discussed, and the mosaic of barbel behaviours observed is compared with available laboratory and field studies. Copyright © 2005 John Wiley & Sons, Ltd.
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Assessing temporal variation and autocorrelation in fish habitat use
Folia Zoologica, 2005Co-Authors: Lorenzo Vilizzi, Gordon Copp, Jean-marc RousselAbstract:We assessed the extent of temporal variation and autocorrelation in fish habitat use based on an experimental study of individual 0+ juvenile barbel, barbus barbus, in an artificial flume. Five treated and five control fish were individually subjected to an increase in discharge (intervention) halfway through each experiment and kept at baseline discharge throughout, respectively. Preference curves for velocity were generated for each of 60 trials per experiment and for each combination of treated/control (fish) x before/after-intervention. There were large between- and within-individual differences in velocity preference, both in treated and in control fish. Most barbel explored the entire range of velocities, whereas some individuals used a more limited range. Temporal variation in behavioural responses was assessed by a PCA-based methodology. Autocorrelation (i.e. correlation between sequential trials) was diagnosed in most response profiles, supporting recent findings that individuals may have a 'memory' of their past velocity usage. The relevance of the results for numerical habitat models of fish habitat assessment is discussed, as well as the importance of incorporating temporal variability into fish habitat use models (e.g. PHABSIM), not only as ontogenetic intervals but also as longitudinal data of individual behaviours. A warning is also re-issued about the erroneous belief of 'pseudoreplication' simply arising from repeated measurements in time.
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Assessing variation in suitability curves and electivity profiles in temporal studies of fish habitat use
River Research and Applications, 2004Co-Authors: Lorenzo Vilizzi, G.h. Copp, Jean-marc RousselAbstract:Under experimental conditions, we tested whether variations in preference curves, weighted usable areas, and electivity profiles for velocity of 0+ juvenile barbel barbus barbus could be attributed to environmental variables (discharge, water depth, time of day) and/or time of sampling. We elaborated preference curves and weighted usable areas according to the Instream Flow Incremental Methodology, as well as electivity profiles. Variation among preference curves, weighted usable areas and electivity profiles was always observed, regardless of time of day, water depth, or discharge combinations. Our results support published concerns that the shape of preference curves is highly dependent on the time of data collection, and that curves derived from a single field sampling excursion can be viewed as representative for that moment in time only, whereas curves generated as composites from typological or time-series samples may provide an approximation for a study area, but at the expense of between-site and/or between-date variation. Spatial/temporal variation is an important aspect of fish habitat studies and should be incorporated as a (layered) component into descriptive/predictive models. To this end, we illustrate how a PCA-based technique and log-linear modelling can be used to assess temporal patterns in collections of preference curves and electivity profiles, respectively.
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Behavioural responses of juvenile barbel in an artificial channel: distribution and velocity use
Animal Behaviour, 2001Co-Authors: Lorenzo Vilizzi, Gordon H CoppAbstract:Abstract To determine the combined effects of depth, discharge and time of day on the distribution and velocity use of juvenile barbel, barbus barbus, we observed groups of 20 fish over replicate 24-h periods at dawn, midday, dusk and midnight in an artificial channel. Four combinations of depth and discharge were examined (low depth–low discharge: LDLS; high depth–low discharge: HDLS; low depth–high discharge: LDHS; high depth–high discharge: HDHS). At dawn and midday, the fish were more aggregated than at dusk and midnight, regardless of depth and discharge. However, the latter variables did have a subtle effect on distribution, but only through a complex interaction with time of day, which we detected by a combination of a modified index of distribution and a wider reference lattice. In particular, at dusk and midnight juvenile barbel were dispersed under lentic conditions of HDLS, were reaggregated when velocities increased at LDLS and HDHS, and were dispersed again under the more lotic conditions of LDHS. Furthermore, the weighted used area for velocity decreased dramatically under LDHS and was highest at HDLS. The ecological significance of these results is discussed, with special attention to their likely consequences for foraging, growth and, ultimately, recruitment success in barbel.
T. Faure - One of the best experts on this subject based on the ideXlab platform.
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Méthodes et outils d'analyse spatiale des habitats des poissons en contexte fluvial anthropisé
Ingénieries eau-agriculture-territoires, 2007Co-Authors: C. Le Pichon, Guillaume Gorges, François Goreaud, J. Baudry, H. Boussard, T. Faure, Philippe BoëtAbstract:Pour qu'elles soient efficaces, les mesures de gestion et de restauration des habitats piscicoles devraient considérer la structure spatiale et la connectivité des habitats vitaux nécessaires au cycle de vie des espèces menacées, tout particulièrement dans les cours d'eau fortement aménagés. Or, peu de méthodes opérationnelles de quantification de la structure spatiale et de la connectivité de ces habitats sont disponibles pour établir un diagnostic préalable aux actions de restauration. L'approche décrite dans cet article repose sur le couplage des concepts et des outils de l'écologie des cours d'eau et de l'écologie du paysage. Elle propose un mode de représentation cartographique des habitats des poissons utilisant le système d'informations géographiques et des méthodes et outils logiciels pour en faire leur analyse spatiale qui sont adaptés aux particularités des milieux d'eau courante. Ces méthodes permettent, en particulier, de détecter l'effet des aménagements physiques et de la régulation des débits sur la structure spatiale des habitats vitaux des poissons. L'illustration porte sur le barbeau fluviatile (barbus barbus), une espèce menacée des grands cours d'eau européens aménagés. / Effective management and restoration of habitat for fish should consider how the different vital habitats need to be arranged spatially and their connectivity, especially in human-impacted rivers. As few operational methods are available to study these issues, we propose a riverscape approach based on landscape ecology and stream ecology concepts. It uses a GIS-based habitat mapping and methods and software tools, adapted to the running water characteristics, to make the spatial analysis of fish habitats patterns. These methods allow the detection of the effects of physical alteration and flow regulation on the spatial structure of fish habitats. An illustration is made with the common barbel (barbus barbus), a threatened species in human-impacted European rivers.
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Méthodes et outils d’analyse spatiale des habitats des poissons en contexte fluvial anthropisé
Sciences Eaux & Territoires, 2007Co-Authors: Celine Le Pichon, Guillaume Gorges, Jacques Baudry, François Goreaud, H. Boussard, T. Faure, Philippe BoëtAbstract:Pour qu’elles soient efficaces, les mesures de gestion et de restauration des habitats piscicoles devraient considérer la structure spatiale et la connectivité des habitats vitaux nécessaires au cycle de vie des espèces menacées, tout particulièrement dans les cours d’eau fortement aménagés. Or, peu de méthodes opérationnelles de quantification de la structure spatiale et de la connectivité de ces habitats sont disponibles pour établir un diagnostic préalable aux actions de restauration. L’approche décrite dans cet article repose sur le couplage des concepts et des outils de l’écologie des cours d’eau et de l’écologie du paysage. Elle propose un mode de représentation cartographique des habitats des poissons utilisant le système d’informations géographiques et des méthodes et outils logiciels pour en faire leur analyse spatiale qui sont adaptés aux particularités des milieux d’eau courante. Ces méthodes permettent, en particulier, de détecter l’effet des aménagements physiques et de la régulation des débits sur la structure spatiale des habitats vitaux des poissons. L’illustration porte sur le barbeau fluviatile (barbus barbus), une espèce menacée des grands cours d’eau européens aménagés.
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A Spatially Explicit Resource-Based Approach for Managing Stream Fishes in Riverscapes
Environmental Management, 2006Co-Authors: Céline Le Pichon, Guillaume Gorges, Jacques Baudry, François Goreaud, Philippe Boët, T. FaureAbstract:The article describes a riverscape approach based on landscape ecology concepts, which aims at studying the multiscale relationships between the spatial pattern of stream fish habitat patches and processes depending on fish movements. A review of the literature shows that few operational methods are available to study this relationship due to multiple methodological and practical challenges inherent to underwater environments. We illustrated the approach with literature data on a cyprinid species ( barbus barbus ) and an actual riverscape of the Seine River, France. We represented the underwater environment of fishes for different discharges using two-dimensional geographic information system-based maps of the resource habitat patches, defined according to activities (feeding, resting, and spawning). To quantify spatial patterns at nested levels (resource habitat patch, daily activities area, subpopulation area), we calculated their composition, configuration, complementation, and connectivity with multiple spatial analysis methods: patch metrics, moving-window analysis, and least cost modeling. The proximity index allowed us to evaluate habitat patches of relatively great value, depending on their spatial context, which contributes to the setting of preservation policies. The methods presented to delimit potential daily activities areas and subpopulation areas showed the potential gaps in the biological connectivity of the reach. These methods provided some space for action in restoration schemes.
Philippe Boët - One of the best experts on this subject based on the ideXlab platform.
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Spatial metrics and methods for riverscapes : quantifying variability in riverine fish habitat patterns
Environmetrics, 2009Co-Authors: Celine Le Pichon, Guillaume Gorges, Jacques Baudry, François Goreaud, Philippe BoëtAbstract:Defining the optimal configuration of all habitats required during a life cycle, called vital habitat, is a necessary step for effective management of riverine fishes and restoration of river habitats. Landscape ecology provides many metrics and methods to study the composition and configuration of habitats, but they need to be adapted for fishes in river environments or riverscapes. For example, hydrographic distance seems more appropriate than Euclidean distance for measuring distances between vital habitats in riverscapes.We adapted some metrics to assess habitats patterns of a threatened cyprinid species (barbus barbus) for natural and artificial riverscapes of the Seine river, France. Composition metrics provided essential quantification of the relative abundance of the vital habitats, whereas configuration metrics were relevant to quantify their spatial arrangement and spatial relationships. Nearest-neighbor hydrographic distance was useful to evaluate the influence of flow variability in the natural riverscape, but was not relevant to discriminate the artificial riverscape from the natural one. Conversely, a proximity index revealed high fragmentation in the artificial riverscape. Spatial habitat relationships between feeding and resting habitats, evaluated with a moving window analysis, provided a map of daily activity patches and emphasized the gaps in the biological continuity of the riverscape. The spatial metrics and methods we adapted to the particularities of the Seine river allowed us to detect natural and artificial variability in fish habitat patterns. They should help in evaluating impacts of habitat alteration and isolation and prioritize preservation and restoration policies in human-impacted rivers.
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Méthodes et outils d'analyse spatiale des habitats des poissons en contexte fluvial anthropisé
Ingénieries eau-agriculture-territoires, 2007Co-Authors: C. Le Pichon, Guillaume Gorges, François Goreaud, J. Baudry, H. Boussard, T. Faure, Philippe BoëtAbstract:Pour qu'elles soient efficaces, les mesures de gestion et de restauration des habitats piscicoles devraient considérer la structure spatiale et la connectivité des habitats vitaux nécessaires au cycle de vie des espèces menacées, tout particulièrement dans les cours d'eau fortement aménagés. Or, peu de méthodes opérationnelles de quantification de la structure spatiale et de la connectivité de ces habitats sont disponibles pour établir un diagnostic préalable aux actions de restauration. L'approche décrite dans cet article repose sur le couplage des concepts et des outils de l'écologie des cours d'eau et de l'écologie du paysage. Elle propose un mode de représentation cartographique des habitats des poissons utilisant le système d'informations géographiques et des méthodes et outils logiciels pour en faire leur analyse spatiale qui sont adaptés aux particularités des milieux d'eau courante. Ces méthodes permettent, en particulier, de détecter l'effet des aménagements physiques et de la régulation des débits sur la structure spatiale des habitats vitaux des poissons. L'illustration porte sur le barbeau fluviatile (barbus barbus), une espèce menacée des grands cours d'eau européens aménagés. / Effective management and restoration of habitat for fish should consider how the different vital habitats need to be arranged spatially and their connectivity, especially in human-impacted rivers. As few operational methods are available to study these issues, we propose a riverscape approach based on landscape ecology and stream ecology concepts. It uses a GIS-based habitat mapping and methods and software tools, adapted to the running water characteristics, to make the spatial analysis of fish habitats patterns. These methods allow the detection of the effects of physical alteration and flow regulation on the spatial structure of fish habitats. An illustration is made with the common barbel (barbus barbus), a threatened species in human-impacted European rivers.
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Méthodes et outils d’analyse spatiale des habitats des poissons en contexte fluvial anthropisé
Sciences Eaux & Territoires, 2007Co-Authors: Celine Le Pichon, Guillaume Gorges, Jacques Baudry, François Goreaud, H. Boussard, T. Faure, Philippe BoëtAbstract:Pour qu’elles soient efficaces, les mesures de gestion et de restauration des habitats piscicoles devraient considérer la structure spatiale et la connectivité des habitats vitaux nécessaires au cycle de vie des espèces menacées, tout particulièrement dans les cours d’eau fortement aménagés. Or, peu de méthodes opérationnelles de quantification de la structure spatiale et de la connectivité de ces habitats sont disponibles pour établir un diagnostic préalable aux actions de restauration. L’approche décrite dans cet article repose sur le couplage des concepts et des outils de l’écologie des cours d’eau et de l’écologie du paysage. Elle propose un mode de représentation cartographique des habitats des poissons utilisant le système d’informations géographiques et des méthodes et outils logiciels pour en faire leur analyse spatiale qui sont adaptés aux particularités des milieux d’eau courante. Ces méthodes permettent, en particulier, de détecter l’effet des aménagements physiques et de la régulation des débits sur la structure spatiale des habitats vitaux des poissons. L’illustration porte sur le barbeau fluviatile (barbus barbus), une espèce menacée des grands cours d’eau européens aménagés.
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A Spatially Explicit Resource-Based Approach for Managing Stream Fishes in Riverscapes
Environmental Management, 2006Co-Authors: Céline Le Pichon, Guillaume Gorges, Jacques Baudry, François Goreaud, Philippe Boët, T. FaureAbstract:The article describes a riverscape approach based on landscape ecology concepts, which aims at studying the multiscale relationships between the spatial pattern of stream fish habitat patches and processes depending on fish movements. A review of the literature shows that few operational methods are available to study this relationship due to multiple methodological and practical challenges inherent to underwater environments. We illustrated the approach with literature data on a cyprinid species ( barbus barbus ) and an actual riverscape of the Seine River, France. We represented the underwater environment of fishes for different discharges using two-dimensional geographic information system-based maps of the resource habitat patches, defined according to activities (feeding, resting, and spawning). To quantify spatial patterns at nested levels (resource habitat patch, daily activities area, subpopulation area), we calculated their composition, configuration, complementation, and connectivity with multiple spatial analysis methods: patch metrics, moving-window analysis, and least cost modeling. The proximity index allowed us to evaluate habitat patches of relatively great value, depending on their spatial context, which contributes to the setting of preservation policies. The methods presented to delimit potential daily activities areas and subpopulation areas showed the potential gaps in the biological connectivity of the reach. These methods provided some space for action in restoration schemes.