River-Wide Habitat Availability for Fish Habitat Guilds: Implications for In-Stream Flow Protection

The variation in river discharge alters habitat heterogeneity with implications for the distribution of fish species with different habitat requirements. Assessments of habitat availability following changes in river discharge are difficult to apply at broad spatial scales and with relevance to multiple species. We used a MesoHABSIM modeling approach to quantify river-wide changes in habitat availability for five fish habitat guilds under three river discharge levels along the Niobrara River, NE, USA.We used a time-series of river discharge (1958–2010) to create uniform continuous under-threshold habitat duration curves that identified habitat conditions that may result in periods of stress for fish communities along the Niobrara River. Habitat availability for each fish habitat guild was dependent on river discharge and location along the river. Habitat availability for fish habitat guilds ranged from 5% to 49% of the total channel area suggesting habitat availability may, at times, be limited. We provide river discharge guidelines for bioperiods that limit the frequency and duration of stressful habitat conditions. Understanding interactions between river discharge and habitat availability through time and at river-wide scales may aid in managing for ecological integrity by including protection of river discharge variability to support multiple fish habitat guilds

Physical habitat assessment in the Tajuna river (Spain) by means of the MesoHABSIM approach

Physical habitat was assessed in the Tajuña river (Tagus basin, Spain) by means of the MesoHABSIM approach. Long reaches of the Tajuña river are altered by agricultural use of the riverside. The main impacts are river rectification (straightening), channel entrenchment and incision, and degradation of riparian vegetation, along with important flow depletion and regulation. To our knowledge, this is the first application in Spain of MesoHABSIM, which is a physical habitat model based on the identification of habitat attributes - depth, water velocity, substrate, types of hydromorphologic units (HMU), and types of cover - on the mesohabitat scale. The river was stratified into 16 segments with similar habitat characteristics. Mesohabitats were mapped in one representative site (1-2 km long) within each segment to provide a hydromorphologic model of the river. Biological models were developed for fry, juvenile, and adult brown trout. To do this, preliminary models were generated based on literature about trout habitat requirements, and then they were calibrated with electrofishing data. These models were applied to the hydromorphologic model of the river to quantify the available habitat for brown trout in the current conditions. Finally, restoration action was designed to decrease channel entrenchment, increase river sinuosity, and recover its riparian vegetation. The physical changes after restoration were estimated by expert opinion, and the quantification of the available habitat was done with MesoHABSIM at each site. These results can be used to select the segments that are the best candidates for restoration.Se ha evaluado el hábitat físico en el río Tajuña (cuenca del Tajo, España) mediante la metodología MesoHABSIM. Una parte importante del río Tajuña está alterada por los usos agrícolas de las riberas. Los principales impactos son la rectificación, el encajonamiento e incisión del cauce, y la degradación de la vegetación riparia, junto con una importante extracción y regulación del caudal. Hasta donde conocemos, ésta es la primera aplicación de MesoHABSIM en España. Se trata de un modelo de hábitat físico, basado en la identificación de los atributos del h'abitat -profundidad, velocidad del agua, sustrato, tipo de unidad hidromorfológica (HMU) y tipo de cobertura o refugio- en la escala del mesohábitat. Se estratificó el río en 16 segmentos con características similares de hábitat. En cada segmento se muestrearon los mesohábitats en un tramo representativo de 1-2 km de largo, construyendo así un modelo hidromorfológico del río. Se generaron modelos biológicos para alevines, juveniles y adultos de trucha común. Para ello, se construyeron unos modelos preliminares a partir de bibliografía acerca de los requerimientos de hábitat de la trucha, y después se calibraron con datos obtenidos mediante pesca eléctrica. Estos modelos fueron aplicados al modelo hidromorfológico para cuantificar el hábitat disponible para la trucha común en las condiciones actuales. Finalmente se diseño una acción de restauración con el objetivo de disminuir el encajonamiento del cauce, aumentar su sinuosidad y recuperar su vegetación riparia. Los cambios tras la restauración se estimaron por opinión de experto, y la evaluación del hábitat resultante se realizó mediante MesoHABSIM. Estos resultados pueden emplearse para elegir los segmentos más apropiados para realizar la restauración propuesta

Over 200,000 kilometers of free-flowing river habitat in Europe is altered due to impoundments

European rivers are disconnected by more than one million man-made barriers that physically limit aquatic species migration and contribute to modification of freshwater habitats. Here, a Conceptual Habitat Alteration Model for Ponding is developed to aid in evaluating the effects of impoundments on fish habitats. Fish communities present in rivers with low human impact and their broad environmental settings enable classification of European rivers into 15 macrohabitat types. These classifications, together with the estimated fish sensitivity to alteration of their habitat are used for assessing the impacts of six main barrier types (dams, weirs, sluices, culverts, fords, and ramps). Our results indicate that over 200,000 km or 10% of previously free-flowing river habitat has been altered due to impoundments. Although they appear less frequently, dams, weirs and sluices cause much more habitat alteration than the other types. Their impact is regionally diverse, which is a function of barrier height, type and density, as well as biogeographical location. This work allows us to foresee what potential environmental gain or loss can be expected with planned barrier management actions in rivers, and to prioritize management actions

Session A3 - Neptun: the electronic guidance system that effectively manages fish movement in a down and upstream waterway.

The protection of fish communities at man-made facilities and barriers has a long history of significant expenditure of scientific and monetary resources. Beyond creating fishways, considerable investment is made to protect fish by blocking their access to turbines, water intakes, and directing them to less risky areas. Nevertheless, guiding fish to the fish passages, especially in downstream direction still present a big problem. The anticipated success of electrical fish barriers and guidance structures has been limited due to current design limitations. However, a device with a fundamentally new design feature has been successfully deployed in Poland. The device is called NEPTUN . NEPTUN is an electric-electronic 3-phase barrier, producing a smooth non-uniform pulsed electric field of low voltage. It uses arrays of positive and negative electrodes and gradually increases the intensity of the electric field between the electrodes from positive to negative. Unlike other devices NEPTUN does not stun fish, but affects their neuromuscular system at the informational level, allowing them to escape from the area of the electric field. The basic field installation consists of steel electrodes attached to the river bottom so that they can move from the vertical to an angle of + / - 90 degrees. A buoy attached at the end of the electrode keeps it in an upright position. Groups of electrodes are powered by remotely controlled generators. Specialized software controls the parameters of the electric field, creates statistically-mastered changes, and controls the switching of each group of electrodes. The system supports sensors for monitoring temperature and conductivity of the water which can be used to automatically adjust the properties of the electric field. With an average power input of 0.43 to 0.45 kWh and electricity consumption of 0.0018 kW/m2, NEPTUN has a low operating cost. Additionally, the system maintenance is minimal

Application of the Mesohabitat Simulation System (MesoHABSIM) for Assessing Impact of River Maintenance and Restoration Measures

Maintenance and restoration activities alter the river morphology and hydrology, and in consequence, alter fish habitats. The aim of this research was to investigate the change of habitat availability for fish guilds after carrying out maintenance works, commonly used river restoration measures and a restoration derived from fish habitat requirements. The selected study site is located at a close to natural condition section of Swider River in central Poland. The MesoHABSIM model was used to assess the area of suitable habitats in this site and predict habitat distribution at all planning scenarios. The affinity index which is a measure of similarity of two distributions showed that the likely distribution of habitats for fish resulting from simulated maintenance is 76.5% similar to that under measured conditions. The distribution of habitats caused by river restoration is also similar to that of the baseline in 73.2%. The resemblance between the restoration scenario focusing on fish habitat requirements and the reference conditions is 93.1%. It is beneficial to define the river restoration measures based on habitat availability for fish community. Modelling is a useful tool to simulate the changes and predict which guilds there is abundance of suitable habitats, and for which there are too few. It allows for more effective use of resources according to quantitative target states

River-Wide Habitat Availability for Fish Habitat Guilds: Implications for In-Stream Flow Protection

The variation in river discharge alters habitat heterogeneity with implications for the distribution of fish species with different habitat requirements. Assessments of habitat availability following changes in river discharge are difficult to apply at broad spatial scales and with relevance to multiple species. We used a MesoHABSIM modeling approach to quantify river-wide changes in habitat availability for five fish habitat guilds under three river discharge levels along the Niobrara River, NE, USA.We used a time-series of river discharge (1958–2010) to create uniform continuous under-threshold habitat duration curves that identified habitat conditions that may result in periods of stress for fish communities along the Niobrara River. Habitat availability for each fish habitat guild was dependent on river discharge and location along the river. Habitat availability for fish habitat guilds ranged from 5% to 49% of the total channel area suggesting habitat availability may, at times, be limited. We provide river discharge guidelines for bioperiods that limit the frequency and duration of stressful habitat conditions. Understanding interactions between river discharge and habitat availability through time and at river-wide scales may aid in managing for ecological integrity by including protection of river discharge variability to support multiple fish habitat guilds

Over 200,000 kilometers of free-flowing river habitat in Europe is altered due to impoundments.

Fish guild data and results.xlsx - fish guilds data used for river types classification. The file contains proportions of each fish guild at non-disturbed sites. \n \n Fields: \n Site_code - Non-disturbed site (NDS) identifier as in the Intercalibration Dataset \n FCMacHT - Fish Community Macrohabitat Type \n HYMO.type - River type derrived from broad environmental characteristics only \n Highly rheophilic, intolerant species - Fish guild proportion of intolerant highly rheophilic species \n Rheophilic benthic species, preferring sandy-gravel bottom substrate - Fish guild proportion of rheophilic benthic species preferring sandy-gravel bottom substrate \n Rheophilic water column species, preferring sandy-gravel bottom substrate - Fish guild proportion of rheophilic water column species preferring sandy-gravel bottom substrate \n Limnophilic benthic species of moderate tolerance - Fish guild proportion of limnophilic benthic species of moderate tolerance \n Limnophilic water column species of moderate tolerance - Fish guild proportion of limnophilic water column species of moderate tolerance \n Intolerant, rheophilic benthic species, preferring detritus or pelal bottom substrate - Fish guild proportion of intolerant rheophilic benthic species preferring detritus or pelal bottom substrate \n Intolerant, water column species - Fish guild proportion of intolerant water column species \n Limnophilic lithophilic species of moderate tolerance - Fish guild proportion of limnophilic lithophilic species of moderate tolerance \n Limnophilic phytophilic species of moderate tolerance - Fish guild proportion of limnophilic phytophilic species of moderate tolerance \n Benthic species of moderate tolerance - Fish guild proportion of benthic species of moderate tolerance \n Generalists - tolerant species - Fish guild proportion of tolerant generalist species \n \n \n NDS_attr.csv - broad environmental attributes for non-disturbed sites \n riv_attr.csv - broad environmental attributes for river segments generated with CART results \n \n Fields: \n WSO1_ID, Riversegment identifier as in CCM2.1 dataset\n W_CATCH, Catchment size upstream a given riversegment, derived from CCM2.1 dataset\n W_SLOPE, Slope of river segment, derived from CCM2.1 dataset\n W_STRAHL, Strahler stream order of river segment, derived from CCM2.1 dataset\n W_ALT, Mean altitude of riversegment, derived from CCM2.1 dataset\n Z_GEO3_SI, Geology of immediate catchment of riversegment classified as siliceaous (1,0 values), derrived from IHME1500 v 1.2\n Z_GEO3_CA, Geology of immediate catchment of riversegment classified as calcareous (1,0 values), derrived from IHME1500 v 1.2\n Z_GEO3_OR, Geology of immediate catchment of riversegment classified as organic (1,0 values), derrived from SGDB v 2.0\n EnZ_01ALN, Environmental Zone of immediate catchment of riversegment based on EnZ - Alpine North zone (1,0 values)\n EnZ_02BOR, Environmental Zone of immediate catchment of riversegment based on EnZ - Boreal zone (1,0 values)\n EnZ_03NEM, Environmental Zone of immediate catchment of riversegment based on EnZ - Nemoral zone (1,0 values)\n EnZ_04ATN, Environmental Zone of immediate catchment of riversegment based on EnZ - Atlantic North zone (1,0 values)\n EnZ_05ALS, Environmental Zone of immediate catchment of riversegment based on EnZ - Atlantic South zone (1,0 values)\n EnZ_06CON, Environmental Zone of immediate catchment of riversegment based on EnZ - Continental zone (1,0 values)\n EnZ_07ATC, Environmental Zone of immediate catchment of riversegment based on EnZ - Atlantic Central zone (1,0 values)\n EnZ_08PAN, Environmental Zone of immediate catchment of riversegment based on EnZ - Pannonian zone (1,0 values)\n EnZ_09LUS, Environmental Zone of immediate catchment of riversegment based on EnZ - Lusitanian zone (1,0 values)\n EnZ_10ANA, Environmental Zone of immediate catchment of riversegment based on EnZ - Anatolian zone (1,0 values)\n EnZ_11MDM, Environmental Zone of immediate catchment of riversegment based on EnZ - Mediterranean Mountains zone (1,0 values)\n EnZ_12MDN, Environmental Zone of immediate catchment of riversegment based on EnZ - Mediterranean North zone (1,0 values)\n EnZ_13MDS, Environmental Zone of immediate catchment of riversegment based on EnZ - Meaditerranean South zone (1,0 values)\n FCMacHT, Calculated Fish Community Macrohabitat Type \n \n\n barriers_results.csv - barriers analysis results for dams, weirs and sluices with height, including macrohabitat type, wRHp, river segment slope, estimated impoundment length of known barriers, estimated remaining habitat for known barriers \n \n Fields: \n GUID, barrier ID based on AMBER Barrier Atlas \n Height, barrier height as in AMBER Barrier Atlas \n type_, barrier type as in AMBER Barrier Atlas \n WSO1_ID, Riversegment identifier as in CCM2.1 dataset \n FCMacHT, Fish Community Macrohabitat Type \n wRHp, remaining Riverine Habitat proportion \n slope, river segment slope (%) derived from CCM2.1. \n impound_l, estimated imboundment length, calculated as height/slope (m) \n b_wRHp, estimated length of the remaining riverine habitat proportion (wRHp) of a barrier impounded section (m), calculated as: [wRHp]/100*[impound_l] \n \n \n riv_results.csv - river segments as in CCM2.1 with calculated values of macrohabitat types, wRHp for each barrier type and madian wRHp for a catchment \n \n Fields: \n FCMacHT, Calculated Fish Community Macrohabitat Type \n Sens_score, FCMacHT sensitivity scores \n Sens_class, FCMacHT sensitivity class (highest, moderate, lowest) \n wRHp_dam, wRHp value for dams \n wRHp_weir, wRHp value for weirs \n wRHp_sluic, wRHp value for sluices \n wRHp_culv, wRHp value for culverts \n wRHp_ford, wRHp value for fords \n wRHp_ramp, wRHp value for ramps \n med_wRHp, median value of wRHp for a catchment \n \n \n EDFigure1.pdf - high resolution version of Supplementary Figure 1. \n \n \n Source datasets: \n \n IC: Data located at Joint Research Centre. Access can be granted upon written request. \n AMBER Barrier Atlas: AMBER Consortium. The AMBER Barrier Atlas. A Pan-European database of artificial instream barriers. Version 1.0 June 29th 2020. [dataset]. (2020).\n CCM 2.1: De Jager, A. & Vogt, J. Rivers and Catchments of Europe - Catchment Characterisation Model (CCM). [dataset]. (European Commission, Joint Research Centre (JRC), 2007). \n IHME1500: BgR & UNESCO. International Hydrogeological Map of Europe 1:1,500,000 (IHME1500). Digital map data v1.2. (Federal Institute for Geosciences and Natural Resources (BGR), 2019). \n SGDB: Soil Geographical Database of Eurasia at scale 1:000,000 version 4 beta [dataset]. in The European Soil Database distribution version 2.0, CD-ROM vol. EUR 19945 EN (European Commission, 2004). \n EnZ: Metzger, M. J. The Environmental Stratification of Europe [dataset]. (University of Edinburg, 2018). \

River-Wide Habitat Availability for Fish Habitat Guilds: Implications for In-Stream Flow Protection

The variation in river discharge alters habitat heterogeneity with implications for the distribution of fish species with different habitat requirements. Assessments of habitat availability following changes in river discharge are difficult to apply at broad spatial scales and with relevance to multiple species. We used a MesoHABSIM modeling approach to quantify river-wide changes in habitat availability for five fish habitat guilds under three river discharge levels along the Niobrara River, NE, USA. We used a time-series of river discharge (1958−2010) to create uniform continuous under-threshold habitat duration curves that identified habitat conditions that may result in periods of stress for fish communities along the Niobrara River. Habitat availability for each fish habitat guild was dependent on river discharge and location along the river. Habitat availability for fish habitat guilds ranged from 5% to 49% of the total channel area suggesting habitat availability may, at times, be limited. We provide river discharge guidelines for bioperiods that limit the frequency and duration of stressful habitat conditions. Understanding interactions between river discharge and habitat availability through time and at river-wide scales may aid in managing for ecological integrity by including protection of river discharge variability to support multiple fish habitat guilds