Methodology for fish assemblages habitat ...

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METHODOLOGY FOR FISH ASSEMBLAGES HABITAT ASSESSMENT IN LARGE RIVERS. APPLICATION IN THE GARONNE RIVER (FRANCE).

MarcPOUILLY(l) Yves SOUCHON (2) Yann LE COARER (3) Daniel JOUVE (4)

(1) ORSTOM - Université LYON 1. Bât 403, 43 Bd du 11 Novembre 1918, 69622 VILLEURBANNE France ; [email protected] (2) CEMAGREF 3bis, quai Chauveau CP 220 69336 LYON Cedex 09 - France ; [email protected] (3) CEMAGREF Le Tholonet BP 31 13612 Aix-en-Provence Cedex 1- France ; [email protected] (4) CNR DXHY 2, rue André Bonin 69316 LYON Cedex 4 - France

ABSTRACT

The purpose of this paper was to present a concrete example of habitat simulations for the fish assemblage in the Garonne river (average discharge 200 m3/s) near Toulouse (France). This example reveals how the technical problems of adaptating habitat simulation methodologies in large rivers has been solved. The first of three points discussed is a description of a new tool for acquiring hydraulic data on a non-wadable river, that is compatible with previous data calculation used in classical fish habitat simulation (Phabsim. EVHA). In this case, an Acoustic Current Doppler Profiler ™ was successfully used to measure depths and velocities on cross-sections ; it was limited to a minimum water depth of 0.8 m, due to the 1200 kHz frequency used in this study. Secondly, this study illustrates the linkage of physical data at different flows with multivariate fish habitat models. Global habitat models were available for 13 lifestages from S species (representing 70 % of density of the total assemblage) : barbel (Barbus barbus), gudgeon (Gobio gobio), chub (Leuciscus

cephalus), bleak (Alburnus alburnus) and roach (Rutilus rutilus). Thirdly, the authors propose an interpretation for habitat at two levels : a classical separate target species interpretation or a new procedure mixing several stages and species, that compares the difference between predicted fish assemblage with reference fish assemblage. We show that it is possible to simulate the potential habitat for the whole fish assemblage with individual species models. The relative weak number of species in french rivers, due to historical biogeography, makes it possible. We also propose an approach that simulates the physical behaviour of the stream on vestiges of morphological units, which thus provides potential rehabilitation. The habitat simulation agrees qualitatively with the known habitat use of the species. The range of flows which seems to structure fish assemblage on an annual scale approximates the interannual average

B324 - Modélisation des microhabitats minimum flow. We also discuss the different objectives for river preservation or rehabilitation, depending on the actual ecological status of the hydrosystems. KEY-WORDS : large river, extension of Phabsim methodology, Garonne river (France), fish assemblage, ecological status, fish habitat. Acoustic Current Doppler Profiler ™, EVHA software.

INTRODUCTION During the last quarter of this century, a greater awareness developed of the necessity to manage riverine ecosystem in a more holistic manner (Petts et al., 1989 ; Rabeni, 1992). The dominant reductionist philosophy, which promotes a case by case management of lotie hydrosystems, is centring the holistic management. However, the application of integrated management remains problematic for several reasons : I) there is insufficient knowledge on the dynamic functioning of hydrosystems ; 2) integrated management these evaluates ecological impacts of water development with less precise quantification than in more traditional engineering ; 3) policy makers lack a sound comprehension of integrating ecological requirements. There is a need for more comprehensive methodologies dealing with symbolic biological targets like fish, which could become a measurable "witness" of the efficiency of the management options. The simulation of the change in fish habitat as a result of flow changes are example of how integrated management can be achieved. This became a major challenge for ecohydraulics research starting in 1975, when permanent conflicts on quantitative water use and relicensing hydroelectric powerplants arose in several countries. Tools which combine hydraulic simulation and fish habitat requirements have preceded safe theory and knowledge on fish habitat and population dynamics (Gaudin et al., 199S). Nevertheless, people working on minimum flow assessment greatly appreciate methodologies widely used (Reiser et al. 1989 ; Armour and Taylor, 1992) like IHM including PHABSIM (Stalnaker, 1979 ; Bovee, 1982 and 1986) and clones (RSS, Killingtveit and Fossdal 1994 ; EVHA. Ginot 1995). They accepted temporally the coarsness of the tool and their helped by their concrete questions to improve several points of the methodology. As pointed out by Stalnaker (1993) and others (Orth. 1987 and 1995; Pouilly and Souchon. 1995), more effort must be made towards including biological explanations and the validity of fish habitat simulation. In this field, the prediction of the spatial well being of complex fish assemblages in large rivers appeared to be specially difficult. This is complicated by inadequate physical description of rivers, where cost effective field data collection (depth, velocity and substrate) are difficult such as in non-wadable rivers. To deal with diverse fish assemblages, different solutions have been proposed : - selection of limited target fish species (Bovee, 1986) in a wide range of habitat needs, representative of major habitat-use guilds (Leonard and Orth, 1988 ). Minimum flow assessments could be based on the intermediate guild between edge-dwelling and fast-water guilds (Jowett and Richardson, 1995), - selection of species on the basis of economical (salmon, brown trout) or symbolic consideration (Hippopotamus amphibius) (Gore et al. I992). The difficulty with numerous species and life stages is to objectively choose the weighting criteria between them. One needs choose a good compromise between the needs of all species ? Leonard et al. (1987) proposed for rivers the flow that provides the maximum habitat for the most critical limited habitat of all

ÊcohydrauUque 2000. juin ¡996. Québec

Habitat modeling -B325 pecies lifestages throughout the year. This could be acceptable for a case expertise, but we still lack of validation criteria, in particular what habitat threshold or duration act as bottlenecks responsible for temporal building of the fish assemblages ?. This paper presents a concrete exa'mple of habitat simulations for the fish assemblage in the Garonne river near Toulouse (France), which addresses the problems of adaptation of Phabsim types of methodologies in large rivers. Three points were presented : (1) description of a new tool for acquiring hydraulic data on a non-wadable river, that is compatible with previous data calculation used in classical fish habitat simulation (Phabsim, EVHA), (2) illustration of the linkage of physical data at different flows with multivariate fish habitat models, (3) proposals an interpretation for habitat at two levels : a classical separate target species interpretation or a new procedure mixing several stages and species, that compares the difference between predicted fish assemblage with reference fish assemblage. METHODS • V

Site description : Garonne is the major river in South West of France. The head of the basin takes place in Pyrénées mountains. Upstream from Toulouse, a large tributary called Ariège joined Garonne. After this confluence, the mean annual discharge is 200 m3/s (Sormail 1989), and the river exhibits a nival hydrological regime. Several upstream dams regulate the discharge and provide irrigation waters. As a result, the low flow during the summer for 10 consecutive days declines to 40 m3/s (Sormail 1989). There is only one channel in this area.. Downstream from Toulouse, dredging activities during the last 30 years lowered the river level from its historical less of 2 meters. Most of the alluvial substrate has desappeared, and the natural sequence of units has been modified. The river bed is now dominated by molassic paving, and the typical riffle units have been largely eliminated. It is in therefore remaining areas that we choose to analyze. This allows us to infer what could be the effect of susbtrate and discharge restoration. Habitat description survey Two replicate samples sites were established in the first 10 km downstream from Toulouse. These site locations were chosen to represent a maximum of habitat conditions and substrate in the remaining natural areas. The general procedure is the same as the transect description procedure described in Pouilly et al. (1995, adapted from Bovee 1982). The mean water depth was more than 0.8 m, which permited us to use of the Acoustic Current Doppler Profiler (ADCP, RD Instruments compagny ™, San Diego California-USA) based on water depth and current velocity. Six transects were chosen in site 1 and seven in site 2. Each transect was performed perpendicular to the major direction of the flow. They were described by ADCP during 4 surveys. For an average of 100 m width, it took approximative^ five minutes for one boat survey .The margin of the transect was localised precisely by a laser theodolite, and ADCP was able to determine the boat trajectory with an integrate compass and an estimation of the boat speed. When the Ecohydraulics 2000, June 1996, Quebec

B326 -Modélisation des microhabitats ADCP could not measure the margin of the transect because of too shallow water depth, then we used tfj propeler method for determining velocity and depth (0TT-C2 propeler T "). Eich transect was described hv several cells defined by upstream and downstream representative limits and by a mean width of I meter (100 ± 10 cells for a width between 100 and 120 meters). Each cell gave the local hydraulic conditions corresponding to the measurements taken by the current propeler or the mean of the four survey done by the ADCP. This procedure gave the topographic and hydraulic information necessary to use EVHA software to evaluate fish habitat (Ginot and Souchon 1995).

How the ADCP works (Gordon 1989) The gear is composed of a cylinder (diameter 22 cm. height 60 cm. weight 23 kg) which supports four transducers, and by an electronic interface (deckbox) compacted to a computer. The four transducers were oriented at an angle of 30° relative to the vertical and in 90° azimuth increments. The transducer cylinder is installed vertically on the side of a boat and kept enough (around 15 cm) to ensure that bubbles do not get under the transducer faces when the boat is underway. ADCPs transmit short acoustic pulses along narrow beams on one frequency. Several gears exist, each with one frequency adapted to one water depth range. Lower frequencies produce greater range whereas higher frequencies produce finer resolution. We used the frequency of 1200 kHz which is adapted to a water depth of 0.8 to 20 meters. The ADCP processes and records the echoes from successive volumes along the beams to determine how much the frequency has changed. The difference in frequency between transmitted and reflected sound is proportional to the relative velocity between the ADCP and the small particules in the water that reflect sound (plankton, suspended sediment). This frequency shift results from the Doppier effect. Each transducer provides a measure of water depth and computes velocity in a series of contiguous cells (one every 25 cm depth). Using four transducers produces a three dimensional velocity vector for each cell and cross check the data quality. The software associated with the deckbox produces real time results which allowed us to determine that the ADCP was working correctly.

The hydraulic model Calculations of depth and velocity for a wide range of flows was made using an hydraulic model based on Limerinos formula (Ginot and Souchon 1995 : see also Pouilly et al. 1995 for a detailed description of the model). This model is available on EVHA software developped at Cemagref Lyon (Ginot and Souchon 1995). Estimating species lifestages habitat Habitat models were available for 13 lifestages from 5 species of the assemblage, all of which were examined (Table 1). They represent 70 % of density of the total assemblage (Pouilly and Souchon 1995). and correspond to the available fish habitat models. Barbel {Barbus barbus) and gudgeon~(GV>/w; gobio) are benthical and rheophilic species. Chub {Leuciscus cephalus) and bleak (Alhurnus alburnus)

are

ubiquitous for velocity. Roach {Rutilus rutilus) ¡s a lenitophilic species. The species were divided in two or three lifestages based on the natural breaks of size frequency histograms.

Ècohydraulique 2000. juin 1996. Québec

Habitat modeling -B327 habitat models were developed first in the Rhône basin (667 microzones, Pouilly, 1995). One and twenty seven electroshocked microzones from the Garonne river were also available (Pouilly '"* hon, 1995). In order to offer a broader range of habitat conditions sampled, we have decided that r to pool the two data bases and to,work with general habitat models for the 794 microzones, ^Habitat simulation for one discharge and one species lifestage was computed using two types of ation : "~- the local values of current velocity and water depth, derived from the hydraulic model, and substrate description, M | Í - coefficients from the multiple regression between species lifestage density and values of current veracity, water depth and substrate. This biological model is based on multivariate coefficients and has been deyelopped following the procedure described by Pouilly (1995). >!

"

Habitat expressed as Potential Usable Area, was then estimated by the formula :

:

PUA(j) = I Ai * ( C(j,d)*Di + C(j.v)*Vi + C(j.s)*Si + Cste(j) )

|¿! PUA(j) = Potentially Usable Area for the species lifestage j Ai = Area of cell i of a transect of a station Di, Vi, Si = value of depth (d), current velocity (v) and substrate (s) in cell i C(j,d), C(j,v), C(j,s) = regression coefficients of depth (d), current velocity (v) and susbtrate (s) for the species j Cste(j) = regression intercept PUA(j) could be summed by transect or by station. Because of standardized densities in the regression, JA corresponded to density coefficient rather than to real densities. The PUA were estimated for different rges, furnishing an evolution of the potential habitat for the lifestage species versus discharge. General interpretation at the assemblage level '

The evolution of the potential habitat versus discharge could be estimated for each of all the

lestages of the 5 principal species of the assemblage. It resulted many different shapes of habitat evolutions stage by stage, which compromised a simple interpretation of all these informations. An actual reference of the fish assemblage was established in a more natural reach of the river 10 km upstream from Toulouse (Pouilly and Souchon 1995). One possible interpretation on potential habitat was Jfcsearch which discharge in the two replicate sites produced the closest estimated assemblage to the reference assemblage. By doing this, we hypothesized that habitat is a major determinant for shaping fish assemblages in flowing waters (Horwitz, 1978 ; Jowett, 1992 ; Souchon, 1994). The' proposed interpretation was estimated by the sum of the square of the difference between the estimated and reference proportion of each lifestage species in the assemblage (Table 1 ) : Prox(Q) = I (Pe(Q,j)-Pr(j))2 with: Ecohydraulics 2000, June 1996, Québec

B328 -Modélisation des microhabitats Prox(Q) = proximity between the estimated and reference assemblage for the discharge Q Pe(Qj) = relative proportion of the species lifestage j in the estimated assemblage for the discharge Q Pr(j) = relative proportion of the species lifestage j in the reference fish assemblage of the Garonne.

RESULTS Physical description versus discharge for each site Figure 1 gives an example of depths and current velocities from the four ADCP surveys on a transect. The results were consistant and it was possible to average data for each elementary cell. The hydraulic modeling was performed between 20 and 300 m3/s. For the two sites, this range of discharge included severe low flow and the mean annual discharge (Sormail 1989). Table 2 shows the principal characteristics of the stations for these discharges. Site 1 was 415 meters long and was analysed by six transects. The mean channel slope was 0,0001. Transects 1, 2, 5 and 6 correspond to fast, shallow channel, whereas transects 3 and 4 were deeper and slower. This station was straight and this corresponded to a symetrical transverse section for all the transects.The water depth and the wetted area increased continuously with increased discharge, with a slow and down after reaching 85 m3/s. Site 2 was 610 meters long,, with a mean slope was 0.0005. It was analysed by 7 transects. Transect 7 described a long downstream riffle, with a slope of 0.0011. This riffle constituted a sill which made the upstream deeper and slower. Transects 1 and 6 represented a fast flowing channel, whereas transects 2 to 5 were deeper and slower. Station 2 corresponds to a river curve with a symetrical transects. The water depth and the wetted area increased quickly from 20 to 100 m3/s, but remained stable because of a steepside transversal section.The slope and the steeps of station 2 had faster velocities than in station 1 (Table 2). Species lifestages' potential habitat The shape of the curves of PUA versus discharge was quite similar in the two stations for the 13 lifestages (fig. 2a and b). The habitat conditions for small fish, lifestages 1 (except for roach), decreased with increasing discharge. The maximum PUA for these lifestages were between 20 and 50 m3/s. The habitat conditions for lifestages 2 and 3 of bleack and barbel, and the lifestage 3 of chub and roach, increased continuously with increasing discharge and sometines decreased round about 100 m3/s. Their maximum PUA corresponds to 300 m3/s (maximum simulated discharge). The habitat conditions for lifestages 2 of chub were the same as the lifestages 1 results. The habitat conditions of lifestage 1 and 2 increased continuously with discharge at station 1, and decreased (after 100 m3/s for lifestage 1 and after 60m3/s for lifestage 2) in station 2, which was faster than station 1 (Table 2). Higher discharge rates in station one favored large individuals of chub and roach, whereas higher discharge in station 2 favored lifestage two of barbel.

Ècohydraulique 2000, juin 1996, Québec

Habitat modeling -B329 ''' lifcstagcs' potential habitat for a remaining riffle :

',T. Lifestages 1 of all species and lifestages 2 of roach and chub had a maximum PUA at discharges een 40 and 55 m3/s, which decreased quickly (fig. 3). This favored lifestages 2 and 3 of barbel (the .rheophilic species), which agrees with what is known about the habitat behaviour of the species, ]y for the feeding areas (Baras, 1982).

General interpretation at the assemblage level The difference between the estimated and the reference assemblage was very typical for the riffle of station 2. It shows a large decreased (closer to the reference assemblage) between 35 and 60 m3/s (fig. 4). This difference was similar, but unpronounced for all of station 2. This contrasts with station 1 where the difference increased continuously with increased discharge. DISCUSSION Hydraulic data This study provides an example of how the hydraulic description of large river may be described with the Acoustic Doppler Current Profiler. This method provides fast and practical way to obtain sound data (fig. 1). The major problem met with this technique is the choice of the site locations. The water depth limitation (min. 80 cm) makes it difficult to represent all habitat conditions. As a result, riffles and shallow areas could be underestimated. Only one riffle could be described (transect 7 station 2), which represented fast velocity conditions and a natural morphological unit. Current research tries to improve shallow water measurements in this process. The ADCP is usefull to produce the elementary geometry for basic 1D hydraulic simulation in Phabsim family softwares. The ADCP better represents the longitudinal dimension because of the pidity of the measurements. It appearss also compatible with new 2D hydraulic modeling (Ledere et al. l a n d offers the possibility to check physical parameter simulations at different discharges. This method buttnecises Stalnaker et al. (1989) optimism, that physical sampling is feasable in non-wadable

rivers. Fish habitat models and simulations Poor data quality and non availability of fish habitat models could limit the application of Phabsim jnethodologies. For example, Gore and Nestler (1988) recommended working exclusively with regional -V" i' .

based fish habitat developed on a regional basis . Therefore in the Garonne river, we used general models With'aggregated data from two different geographical basins. For practical management, it is preferable to quickly mobilise the best available knowledge. In this case, we used a general habitat model that produces interpretable and useful results in terms of potential habitats' relationships to flow. However, it is not possible to develop fish habitat model in each Phabsim application. Nevertheles, general habitat models can also yield coherent predictions of fish population in a wide range of hydroecoregions (Brown trout. Salmo trutta fario, France ; Souchon, 1994).

Ecohydraulics 2000, June 1996, Québec

B330 -Modélisation des microhabitats We used multivariate models to counter criticisms about the non-independance of key variables (Mathur ef\ ai, 1986). In our research, the models consider average physical conditions for velocity, depth and substrate in sampled habitat zones. We believe that the models could be further improved by introducing (1) the diversity of local adjacent habitat, (2) such parameters like cover, which can be treated with multivariate approaches. It is also obvious that the progressive incorporation of complexity and marginal habitat use by fish (Conder and Annear 1987) will improve the models' accuracy. The lifestages' evolutions of potential habitat were similar for all the small fish, while the larger fish had different evolutions corresponding to their own habitat preferences. However in their early development, all these species have the same habitat preference for shallow and slow water (Copp, 1989 ; Poizat, 1993 ; Pouilly, 1994). Larger adult fish, such as barbel, more rheophilic of these species, preferedhad habitat conditions in the faster locations and especially in the riffles. This contrasts with the more lenitophilic species such as roach, which favours in the slower locations. The others two species (chub and bleack) are more ubiquitous. Habitat conditions for the bleack are the same for both stations and are in the middle scale between roach and barbel. Habitat condition for lifestage 3 of the chub had the same evolution as the roach. The habitat simulation agrees qualitatively with the known habitat behaviour of the species. Definition of river management goals and associate habitat simulation strategy The more precise and explicit the management objectives, the easier it is for scientist to provide sound reseach data to resource managers. The ecological status of the river is the major criteria to consider, given the growing inclusion of environmental goals in national legislation. More precedence is given to purely fisheries considerations. A usefull typology can be described in four categories : (1)- Excellent ecological status, where a preserved hydrosystem is in a quasi pristine state with presence of unique biota. Protection rules would need to be very strict. Total perservation is the goal ; (2)- Reversible ecological status, where the river can still be restored to approximate original conditios. This would require restoration to recover an original situation ; (3)- Degraded ecological conditions, where original conditions cannot be restored. The river could be rehabilitated to a better ecological status ; (4)- Severely degraded ecological status, where the most that can be done is prevent the system from further critical degradation. For this typology, it is important to have a good knowledge on the fish assemblage reference sensu National (USA) Research Council (1992) to evaluate the potential of restoration and to provide a point of comparison to judge the effectiveness of the management plan. This reference could be historical (unfortunately in very few situations), or existing preserved reaches in a river or a similar regional stream. In this study no historical fish assemblage reference exists. The comparison was made with an actual reference to an existing reach with active morphodynamic and unaltered substrate. A more degraded dowstream reach of the Garonne river was impacted by a project of flow regime modification, therefore we selected replicate habitat study stations in the less degraded reach in order to offer two possible interpretations : the potential of rehabilitation through morphological improvements (i.e. substrate refill)

Écohydraulìque 2000, juin 1996, Québec

Habitat modeling -B331 ídrthe potential of rehabilitation through flow regulations, which will not degrade the actual state. This xa not allow usto compare observed fish assemblage with simulated potential habitat. )r the choice of the target fish species, we propose an interpretation at the total assemblage level, evertheless, others biological models have to be developed to complete the actual possibility with 13 fcstages and species, for instance 70 % of the total average fish density. We think that it is both possible ;d desiderable to develop future fish habitat models for a maximum number of species, which is therefore jnsidered as an utopia by Bay ley & Li (1992) for tropical area.s. In temperate areas such as Europe, the :lative low number number of fish species, makes perhaps this an achievable goal. If a model focusses on sh species with known habitat requirements, such as salmonids, the importance of the rare, endangered, .ological key species (Thyus and Karp, 1989), could be underestimated. In assemblages with numerous ;ecies, the fish habitat guild procedures appear to offer a good compromise (Leonard and Orth, 1987 ; lain and Boltz, 1989).

'he fish habitat interpretation at the assemblage level -lore biology (Stalnaker, 1993) or a better ecological view (Orth, 1987 and 1995 ; Pouilly and Souchon, 995) in interpretation of fish habitat requires developments of

new weightings factors between the

lifferent lifestages and species of fish along with an integrated representation of river response versus flow, because biological models were not developed on a seasonal pattern and because we did not analyze the .ydrologic cycle, we compared the results to a global observed result (i.e. the mean assemblage imposition). Leonard et al. (1986) used an optimization matrice to identify the flow that provides the "naximum habitat for the most critically habitat limited lifestage. This procedure assigns the same weight "or each species/lifestages. regardless of dominance. As the result, we used the reference assemblage for comparisons and we searched for the discharge which gave the most closed estimated assemblage. This procedure compared the results of all the species lifestages. The most interesting results showed that (1) only the remaining morphological unit produced a predicted assemblage closest to the reference one and (2)'the pluriannual average monthly low flow produced the best approximation of the global structure of the fish assemblage. This record for the Garonne cyprinids fish assemblage, is similar to previous observations on salmonids communities, especially brown trout (Souchon et ai, 1989 ; Jowett, 1992). Our procedure presuppose that all the the biological models have a similar accuracy. If one of them was less accurate, the estimation error made on one species lifestage would affect the estimation on the assemblage. Table 1 showed the accuracy of the models used. Additionally some portions of the stream may have physical conditions at high flows very different from the conditions where the habitat models were validated. According to Gore and Nestler (1988), error is introduced when habitat changes are projected for discharges that are different from those used when the suitability curve was developed. A sensitivity analysis could help to avoid missinterpretation, by checking different stages during the simulation procedure (i.e. depths or velocities ranges) ; this is possible when using some convivial softwares (EVHA ; Ginot. 1995). It is possible to describe the physical conditions of fish habitat in large non-wadable rivers. The future challenge is to interprete habitat simulation in a broader ecological perspective. We have shown that need to Ecohydraulics 2000, June 1996, Québec

oói¿ -Modélisation des microhabitats

be addressed questions based on definition of management objectives, as well as how to choose a reference that provides a sound interpretation of the potential fish habitat versus flow. Progress must be made in validating biological models for dynamic comprehension (i.e. habitat times series) (Capra et al. 1995 ¡Pouilly and Souchon, 1995), interpretating habitat results, and validating the biological use of habitat simulation methodologies. ACKNOWLEDGEMENTS We thank Professor Belaud and all his staff from Ecole Nationale Supérieure Agronomique de Toulouse and P. Roger from Cemagref for helping with the collection of biological data.. Doug Me Lain and Sylvie Valentin help us to deeply revise the english langage of a previous draft. This study was partially funded by the Agence de l'eau Adour- Garonne. We thank particularly F. Simonet, M.Roux and R. Lohou for encouraging an experimental methodology. The study is a contribution to a scientific program of Cemagref titled " hydrodynamic and ecology in running waters ". REFERENCES Bain M.B., Boltz J.M. (1989). Regulated streamflow and warmwater stream fish : a general hypothesis ana research agenda. U.S. Fish and Wildlife Service, Alabama : Biological report 89 (18). Bayley P.B., Li H.W. (1992). Riverine fishes. In : Calow P. & Petts G.E. (eds), The rivers handbook. Blackwell Scientific Publications, Oxford pp 251-281. Bovee K.D. (1982). A guide to stream habitat analysis using the Instream Flow Incremental Methodology. U.S.D.I. Fish and Wildlife Service, Office of Biological Services, Fort Collins, Colorado. : Instream Flow Information Paper n°12, FWS/OBS 82/86 : 248 p. Bovee K.D. (1986). Development and evaluation of habitat suitability criteria for use in the instream flo* incremental methodology. Fish and Wildlife Service, Office of Biological Service, Ft Collins : Instream Flow Information Paper n° 21, FWS/OBS 86/7 :188p. Capra H., Valentin S., Breil P. (1995). Chroniques d'habitat et dynamique des populations de truite. Bull. Fr. Pêche et Piscic. 337-338-339 pp. 337-344. , Conder A.L., Annear T.C. (1987). Test of weighted usable area estimates derived from a PHABSIM model foi instream flow studies on trout streams. North American Journal of Fisheries Management. 7 pp. 339350. Copp G.H. (1989). The habitat diversity and fish reproductive function of floodplain ecosystems. Environmental Biology of Fishes. 26 pp. 1-27. Gaudin P., Souchon Y., Orth D.J., Vigneux E. (1995). Habitat poissons. In : Colloque "Habitat poissons". Villeurbanne. Bull. Fr. Pêche et Piscic. 337-338-339 pp 1-418. Ginot V. (1995). EVHA : Un logiciel d'évaluation de l'habitat du poisson sous Windows. Bull. Fr. Pêche et Piscic. 337-338-339 pp. 303-308. Ginot V., Souchon Y. (1995). Logiciel EVHA. Evaluation de l'habitat physique des poissons en rivière (version 1.0, beta testJ.Vol. 1. Guide méthodologique. Vol. 2. Guide de l'utilisateur. Cemagref BEA/LHQ Lyon, France, et Ministère de l'Environnement, Dir. de l'Eau, Paris, France.56 p et 109 p. + annexes. Gordon R.L. (1989). Acoustic measurement of river discharge. Journal of Hydraulic Engineering.l 15 (7) pp925-936. Gore J.A., Layzer J.B., Rüssel I.A. (1992). Non traditional applications of instream flow techniques for conserving habitat of biota in the Sabie River of southern Africa. River conservation and Management 11 pp. 162-177. Gore J.A., Nestler J.M. (1988). Instream flow studies in perspective. Regulated Rivers: Research & Management. 2 pp. 93-101. Gore J.A., Nestler J.M., Layzer J.B. (1989). Instream flow predictions and management options for biota affected by peaking-power hydroelectric operations. Regulated Rivers: Research & Management. 3 pp 35-48. Écohydraulique 2000, Juin 1996, Québec

Habitat modeling -B333

J¿RJ.'(1978). Temporal variability patterns and the distributional patterns of stream fishes. Ecological Monographs. 48 pp. 307-321. LG¿ .0992). Models of the abundance of large brown trout in New Zealand rivers. North American journal of Fisheries Management. 12 pp. 417-432. j.Gr; Richardson J. (1995). Habitat preferences of common, riverine New Zealand native fishes and ¿implications for flow management. New Zealand Journal of Marine and Freshwater Research. 29 pp. ^13-23. anitveit A., Fossdal M.L. (1994). The River System Simulator - An integrated model system for watet ^resources planning and operation. In : Hydrosoft 94, 21 - 23 September, Porto Carras, Greece : pp 1-8. •clerc M., Boudreault A., Bechara J.A., Corfa G. (1995). Two-dimensional hydrodynamic modeling : a T- neglected tool in the instream flow incremental methodology. Transactions of the American Fisheries ^Society. 124 (5) pp. 645-662. jooard P.M., Orth DJ. (1988). Use of habitat guilds of fishes to determine Instream Flow requirements. North "'' American Journal of Fisheries Management. 8 pp. 399-409. ¡onard P.M., Orth D.J., Goudreau C.J. (1986). Development of a method for recommending instream flows for Ifishes in the upper James River, Virginia. 152, Blacksburg : 122 p. athur D., Bason W.H., Purdy E.J., Silver C.A. (1985). A critique of the Instream Flow Incremental Methodology. Canadian Journal of Fisheries and Aquatic Sciences. 42 pp. 825-831. ational Research Council (1992). Restoration of aquatic ecosystems. National Academic of Science, National i-Academaic Press, : 552 p. îJjl(1987). Ecological considerations in the development and application of instream flow habitat remodels. Regulated Rivers: Research & Management. 1 pp 171-181. .._.•_. dl DJ. (1995). Food web influences on fish population responses to instream flow. Bull. Fr. Pêche Piscic. '337/338/339 pp. 317-328. rizat G. (1993). Echelle d'observation et variabilité des abondances de juvéniles de poissons dans un secteur aval du Rhône. Thèse de doctorat. Université LYON I : 155p. )uilly M. (1994). Relations entre l'habitat physique et les poissons des zones à cyprinidés rhéophiles dans trois cours d'eau du bassin rhodanien : vers une simulation de la capacité d'accueil pour les peuplements. Doctorat, Université Claude Bernard-Lyon I - BEA/LHQ CEMAGREF : 256 p. uiilly M., Valentin S., Capra H., Ginot V., Souchon Y. (1995). Note technique : Méthode des microhabitats, principes et protocoles d'application. Bulletin Français de Pêche et de Pisciculture. 336 pp 41-54. )uilly S., Souchon Y. (1995). Méthode des microhabitats : validation et perspectives. Bull. Fr. Pêche Piscic. ^•337/338/339 pp. 329-336. benfrCJF. (1992). Habitat evaluation in a watershed context. American Fisheries Society Symposium. 13 pp. r

C Wesche T.A., Estes C. (1989). Status of instream flow legislation and practices in North America. '"Fisheries. 14 (2) pp. 22-29. ^I'L. (1989). Besoins en eau et politique de soutien d'étiage dans la vallée de la Garonne. Revue T*, Géographique des Pyrénées et du Sud-Ouest. 60 (4) pp. 535-548. XïChoirT. (1994). Etat d'avancement des recherches sur la modélisation de l'habitat des poissons en France. # * « / / . Fr. Pêche Piscic. 332 pp. 57-71. wchon Y., Trocherie F., Fragnoud E.f Lacombe C. (1989). Les modèles numériques des microhabitats des ?.O poissons : application et nouveaux développements. Revue des Sciences de l'Eau. 2 pp. 807-830. »Inalar C.B. (1979). The use of habitat structure preferenda for establishing flow regimes necessary foi fctmaintenance of fish habitat. In : Ward, J.V. ¿Stanford, J.A. (eds). The ecology of regulated streams. *?New York : pp 321-337. alnaker C.B. (1993). Fish habitat evaluation models in environmental assessments. In : Hildebrand, S.G. & -gJcCannon, J.B. (eds), Environmental analysis. The NEPA experience. Lewis, Boca Raton, Florida : pp 140-

V-162.

ilnaker C.B., Milhous R.T., Bovee K.D. (1989). Hydrology and hydraulics applied to fishery management in • ' large rivers. Canadian Special Publication Fisheries Aquatic Sciences. 106 pp 13-30. 1ÌS'H.M., Karp C.A. (1989). Habitat use and streamflow needs of rare and endangered fishes, Yampa River, Colorado. U.S. Department of the Interior, Fish and Wildlife service : 27p. aters B.F. (1976). A methodology for evaluating the effects of différents streamflows on salmonid habitat. In : Orsbom, J.F. &AUman, C.H. (eds), Instream Flow Needs. American Fisheries Society, Western Division, Bethesda, Maryland : pp 254-266.

Ecohydraulics 2000, June 1996, Québec

B334 -Modélisation des microhabitats

Table I : Species life-stages relative proportion in Garonne reference assemblage (Pouilly and SouchcJ 1995) and multiple regression coefficients and characteristics • Species life-stage

size range (mm)

relative depth velocity substrate proportion coefficient coefficient coefficient

regression correlation regression intercept coefficient slope

Bleack 1

[30 - 80]

15 .4

-0.00025

-0.00235

-0.02775

0.26509

0.866

0.746

Bleack 2

J80- 120]

0. 1

0.00215

0.0007

-0.01912

-0.038

0.956

0.918

Bleack 3

J120-

0. 2

0.00287

0.00016

-0.0152

-0.09196

0.924

0.724

Barbel 1

[30- 110]

28 .6

-0.00351

0.00031

0.05318

-0.12227

0.917

.838

Barbel 2

J 1 1 0 - 185]

2. 5

-0.00162

0.00571

0.0573

-0.43816

0.859

.915

Barbel 3

J185-

7. 6

0.00132

0.00391

0.05603

-0.56108

0.799

986

Chub 1

[30- 110]

16 .1

-0.00462

-0.00977

-0.07365

1.06653

0.973

733

Chub 2

]110- 170]

0. 2

-0.00034

-0.00579

-0.05463

0.54911

0.611

.785

Chub 3

]170-

2. 0

0.00272

-0.00327

-0.06669

0.35059

0.887

Roach 1

[30 - 90]

1. 8

0.00015

-0.00401

-0.0814

0.63145

0.937

0.78

Roach 2

]90- 150]

0. 9

0.00127

-0.00339

0.00019

0.02405

0.999

0.929

Roach 3

J150-

0. 2

0.00338

-0.00313

-0.0646

0.29157

0.955

0.926

Gudgeon

[30 - 80]

24 .5

-0.00476

-0.00646

-0.03661

0.7375

0.893

1.08

; V £-

'

.972

Table 2 : Hydrodynamics characteristics of two stations and two typical transects described in river Garonne. These characteristics were estimated for two discharges (20 and 300 m3/s) by the hydraulic models of EVHA software (Ginot and Souchon 1995) and from data which comes from ADCP survey (Gordon 1989). mean width (m)

wetted area (*100m2)

max. depth (m)

mean depth (m)

max. \velocity mean velocm (m3/s:1 (m3/s)

20

300

300

20

300

2.9

20 0.78

1.58

0.24

0.98

Discharge (m3/s) 20

300

20

Station 1

70

110

6.0

Station 2

100

130

40.8 62.1 3.8 81.2 105.6 4.0

20 1.5

5.5

1.0

2.0

0.96

2.09

0.25

1.14

Riffle Tr. 7 - sta. 2

95

120

13.2

23.4

0.8

1.9

0.4

1.2

0.96

2.10

0.58

1.46

Deepchannel Tr. 4 - sta. 1

75

135

6.9

9.7

3.1

5.3

2.0

3.4

0.16

1.12

0.12

0.77

Écohydraulìque 2000, juin 1996, Québec

300

300

Habitat modeling -B33S

20.00

40.00

60.00

80.00

100.00

120.00

distance à la nve droite (m) *.'•:-

i|ure 1 : Examples of depths and current velocities measured during four ADCP surveys on a transect on afôhnerivernear Toulouse for a discharge of 210 m3/s. jfc-.

Ecohydraulics 2000, June 1996, Québec

B336 'Modélisation des microhabitats «i

800

A- Bleack

600

e>

I

o

CO */>

Z3

400-

J200 ô 0

800-1

20

100

discharge (m3/s)

200

300

200

300

200

300

200

300

200

300

B- Barbel

600

| xi to

3

400-

§ 200 H o

•••"••••••••,._.

Q.

100

800

discharge (m 3 /s)

C-Chub

co