Habitat evaluation for the endangered fish species Lefua echigonia in the Yagawa River, Japan

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Ecohydraulics on 2019, available online: http://www.tandfonline.com/10.1080/24705357.2019.1614886[EN] Spring-fed streams in Tokyo are important habitats for various aquatic species, whereas urbanization as well as introduction of invasive species is threatening the sustainability of such aquatic ecosystems. This study applies the System for Environmental Flow Analysis (SEFA) in a small urban river in Tokyo to assess the dynamics of the suitable habitats for the endangered freshwater fish Lefua echigonia (Jordan and Richardson 1907). A set of Habitat Suitability Curves (HSCs) for water depth, velocity and substrate was developed to evaluate the suitable habitats. The habitat assessment indicated that the Area Weighted Suitability (AWS) reached the maximum at 0.02 m3/s, which is close to the base flow of the target river; a gradual decrease in AWS was observed for higher flows. The temporal distribution of AWS, during forty-one consecutive months, showed that, on average, the best habitat conditions for adult L. echigonia occur during the period between January and July, whereas the worst situation occurs during the period between August and December. This work presents information and tools for instream habitat analysis that should help managers to conserve this aquatic species and prioritize actions to further rehabilitate urban rivers, using L. echigonia as a case study.We thank Dr. Masaomi Kimura, Masato Kondo, Taichi Kasahara, and Akihiro Tanaka for their support in the field survey. This study was made in part with the support of the JSPS Grants-in-Aid for Scientific Research (Grant number: 17H03886 and 17H04631) and the PROMOE grant for Marina de Miguel Gallo, funded by the Universitat Politecnica de Valencia, between April and August 2018.De-Miguel-Gallo, M.; Martinez-Capel, F.; Muñoz Mas, R.; Aihara, S.; Matsuzawa, Y.; Fukuda, S. (2019). Habitat evaluation for the endangered fish species Lefua echigonia in the Yagawa River, Japan. Journal of Ecohydraulics. 4(2):147-157. https://doi.org/10.1080/24705357.2019.1614886S14715742Bovee KD, Lamb BL, Bartholow JM, Stalnaker CB, Taylor J, Henriksen J. 1998. Stream habitat analysis using the instream flow incremental methodology. U.S. Geological Survey, Biological Resources Division Information and Technology Report USGS/BRD-1998-0004. Fort Collins: U.S. Geological Survey.Bovee KD. 1986. Development and evaluation of habitat suitability criteria for use in the instream flow incremental methodology. Washington, D.C.: U.S. Fish and Wildlife Service Biological Report, 86/7.Lambert TR. 1994. Evaluation of factors causing variability in habitat suitability criteria for Sierra Nevada trout. Environment, Health & Safety. Report 009.4-94.5. San Francisco: Pacific Gas and Electric Company.Martínez-Capel F. 2000. Preferencias de microhábitat de Barbus bocagei, Chondrostoma polylepis y Leuciscus pyrenaicus en la cuenca del río Tajo [PhD Dissertation]. Madrid: Universidad Politécnica de Madrid. (In Spanish)Matsuzawa Y, Aoki K, Fukuda S. 2017a. Critical swimming speed of Lefua echigonia in a laboratory open channel. Proceedings of the Annual Meeting of the Japanese Society of Irrigation Drainage and Reclamation Engineering (JSIDRE). ID: 4-30. Tokyo: Japanese Society of Irrigation Drainage and Reclamation Engineering.Matsuzawa Y, Ohira M, Fukuda S. 2017b. Microhabitat Modelling for an Endangered Freshwater Fish, Lefua Echigonia, in a Spring-Fed Urban Stream. E-Proceedings of the 37th IAHR World Congress. Kuala Lumpur: International Association for Hydro-environment Research and Engineering (IAHR).Poff NL. 2018. Beyond the natural flow regime? Broadening the hydro-ecological foundation to meet environmental flows challenges in a non-stationary world. Freshwater Biol. 63(8):1011–1021

Reservoir compensation releases and the ecology of the River Derwent, Northumberland.

River regulation is commonplace in England and much of the UK. Regulation for the purposes of public water supply causes flows downstream of a reservoir to be attenuated and the flow regime of the channel to be altered. The impact of channel impoundment on a small, upland UK river, has been assessed and methods for mitigation of ecological impacts explored. The method utilised a unique macroinvertebrate data set for pre- and post-impoundment periods to quantify the impact of Derwent Reservoir and the steady, continuous compensation release into the River Derwent, Northumberland. Impacts on the hydrological regime were also investigated and links drawn between changes in flow regime and changes in macroinvertebrate richness and diversity as a result of impoundment. In response to the claim that the impoundment has caused a change in flow regime and had deleterious effects on fish and macroinvertebrates, a compensation redesign tool (CRAB: Compensation Release Assessment at the Broad scale) was employed to design new compensation release regimes from the reservoir which account for the seasonal flow requirements of a number of key fish species. The impact of impoundment on the current flow regime was modelled and the impacts of predicted new regimes were predicted, using a 1D hydrodynamic model (HEC-RAS), as part of a modelling process known as CRAM (Compensation Release Assessment at the Meso-scale). Depth and velocity were the foci of the analysis as they are the two habitat requirements most well documented for the fish species in question, they could be modelled using HEC-RAS and they can act as surrogates for other habitat parameters such as temperature and substrate. The suitability of the depth and velocity combinations predicted using the HEC-RAS model were assessed using fuzzy rule-based modelling, which allowed the habitat quality of a given parameter combination to be quantified. Based on the results of the investigation it was concluded that there has been a change in flow regime and in ecological community structure since impoundment. The flow regime of the River Derwent has become less flashy with fewer extreme events, while macroinvertebrate richness and diversity have increased. The new flow regimes that were designed by CRAB, based on the depth and velocity requirements of brown trout, grayling and Atlantic salmon were predicted through CRAM to have minimal benefits for the fish populations of the River Derwent and it was concluded that no changes to flow regime should be made based solely on the assessment of habitat for fish. Impacts for the macroinvertebrate communities must also be considered as well as the impacts on other aspects of fish habitat including temperature, substrate and cover. A more detailed, micro-scale investigation into the effects of changing flow regime would be required to warrant a change in compensation release regime from Derwent Reservoir

UNDERSTANDING AND ADDRESSING THE ECOLOGICAL IMPACTS OF FLOW IMPOUNDMENT FOR RIVER SYSTEMS IN NORTHERN ENGLAND

Many rivers have undergone flow modification by impoundments to provide services such as water supply and hydropower. There is an established consensus that typical modified flow regimes do not sufficiently cater to the needs of downstream ecosystems, due to species having adapted to natural flow conditions. This may lead to changes in the biodiversity and functional composition of ecosystems, potentially compromising water quality and other river system services. More must be done to understand the relationship between flow and in-stream ecology, in order to mitigate the impacts of flow modification. The development of efficient methods of ecology-flow assessment is vital in order to meet current and future legislation, whilst considering other stakeholders and maintaining the resilience of the local water supply. This thesis combines statistical approaches applied to public datasets, and combined ecological-hydraulic modelling at a case study site, to propose environmental flow regimes. Univariate and multivariate analyses were performed on flow and macroinvertebrate sampling data from sites across northern England. The mean annual frequency of high flow events was identified as a particularly influential driver of functional composition and biodiversity metrics. Field data was gathered and a hydraulic-ecological model was also developed for a selected case study site in order to predict the responses of selected indicator species to flow. Spatial and temporal distributions of habitat quality with respect to flow were generated, allowing the impacts of various flow inputs to be assessed. These findings were integrated in order to generate recommended flow regimes for the case study site. It was demonstrated that the proposed regimes met or improved upon ecological metrics relative to impoundment outflow data, whilst also conserving significant quantities of water. Outcomes from this research demonstrate the potential of habitat suitability models, supplemented by knowledge of ecological-flow relationships, to inform environmental flow design decisions

A modelling approach for evaluating impacts of hydropeaking in a sub-arctic river

Abstract. The release of pulses of water to increase hydroelectric power production at hydropower dams to meet daily peaks in electricity demands is called hydropeaking. Due to energy supply and demand fluctuations, the energy markets direct hydropower companies to balance load fluctuations through variations in power generation which result in flow regulation. More recently, this regulation is being carried out at shorter time intervals i.e., intra-daily and intra-hourly levels. The hydropeaking phenomenon increases drastically at shorter time intervals, severely impacting the riverine and riparian ecosystem. Social, economic, and ecological impacts arise from short-term hydropeaking. Furthermore, recreational services offered by the river are also impacted. This research develops a novel methodology for assessing these impacts in a strongly regulated sub-arctic river in Finland, i.e., Kemijoki River, Ossauskoski-Tervola reach. The methodology combines assessment of seasonal variations in sub-daily hydropeaking, two-dimensional hydrodynamic modelling, and a high-resolution land cover map developed through supervised land use classification via a machine learning algorithm. The results obtained include; the identification of a zone of influence of hydropeaking at sub-daily levels during each season, the total and class-wise area affected during each peaking event, and vulnerability zonation for water-based recreation in the river reach. The overall area of reach affected by peaking in Winter was (1.05 km2), Spring (0.96 km2), Summer (1.39 km2), and Autumn (0.66 km2). A vulnerability mapping was also carried out for the suitability of water-based recreation in the study reach. The novel methodology developed in this research which defines the vulnerable zone of hydropeaking can be used as the first step in detailed impacts assessment studies such as those for impacts on fish habitat and sediment transport processes in the river. The hydropeaking-influenced zone can be used to set thresholds for ecological flows and ramping rates downstream of power stations and opens avenues for future research, development, and policy endeavors for riparian ecosystem impact assessment and mitigation

Implications of movement for species distribution models - rethinking environmental data tools

Movement is considered an essential process in shaping the distributions of species. Nevertheless, most species distribution models (SDMs) still focus solely on environment-species relationships to predict the occurrence of species. Furthermore, the currently used indirect estimates of movement allow to assess habitat accessibility, but do not provide an accurate description of movement. Better proxies of movement are needed to assess the dispersal potential of individual species and to gain a more practical insight in the interconnectivity of communities. Telemetry techniques are rapidly evolving and highly capable to provide explicit descriptions of movement, but their usefulness for SDMs will mainly depend on the ability of these models to deal with hitherto unconsidered ecological processes. More specifically, the integration of movement is likely to affect the environmental data requirements as the connection between environmental and biological data is crucial to provide reliable results. Mobility implies the occupancy of a continuum of space, hence an adequate representation of both geographical and environmental space is paramount to study mobile species distributions. In this context, environmental models, remote sensing techniques and animal-borne environmental sensors are discussed as potential techniques to obtain suitable environmental data. In order to provide an in-depth review of the aforementioned methods, we have chosen to use the modelling of fish distributions as a case study. The high mobility of fish and the often highly variable nature of the aquatic environment generally complicate model development, making it an adequate subject for research. Furthermore, insight into the distribution of fish is of great interest for fish stock assessments and water management worldwide, underlining its practical relevance

Turbulence and Energetic Characteristics of Water Regions Created by Eco-friendly Physical Structures in an Agricultural Dainage Canal

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchive

Shifts in the suitable habitat available for brown trout (Salmo trutta L.) under short-term climate change scenarios

The impact of climate change on the habitat suitability for large brown trout (Salmo trutta L.) was studied in a segment of the Cabriel River (Iberian Peninsula). The future flow and water temperature patterns were simulated at a daily time step with M5 models' trees (NSE of 0.78 and 0.97 respectively) for two short-term scenarios (2011 2040) under the representative concentration pathways (RCP 4.5 and 8.5). An ensemble of five strongly regularized machine learning techniques (generalized additive models, multilayer perceptron ensembles, random forests, support vector machines and fuzzy rule base systems) was used to model the microhabitat suitability (depth, velocity and substrate) during summertime and to evaluate several flows simulated with River2D©. The simulated flow rate and water temperature were combined with the microhabitat assessment to infer bivariate habitat duration curves (BHDCs) under historical conditions and climate change scenarios using either the weighted usable area (WUA) or the Boolean-based suitable area (SA). The forecasts for both scenarios jointly predicted a significant reduction in the flow rate and an increase in water temperature (mean rate of change of ca. −25% and +4% respectively). The five techniques converged on the modelled suitability and habitat preferences; large brown trout selected relatively high flow velocity, large depth and coarse substrate. However, the model developed with support vector machines presented a significantly trimmed output range (max.: 0.38), and thus its predictions were banned from the WUA-based analyses. The BHDCs based on the WUA and the SA broadly matched, indicating an increase in the number of days with less suitable habitat available (WUA and SA) and/or with higher water temperature (trout will endure impoverished environmental conditions ca. 82% of the days). Finally, our results suggested the potential extirpation of the species from the study site during short time spans.The study has been partially funded by the IMPADAPT project (CGL2013-48424-C2-1-R) - Spanish MINECO (Ministerio de Economia y Competitividad) - and FEDER funds and by the Confederacion Hidrografica del Jucar (Spanish Ministry of Agriculture, Food and Environment). We are grateful to the colleagues who worked in the field and in the preliminary data analyses, especially Juan Diego Alcaraz-Henandez, David Argibay, Aina Hernandez and Marta Bargay. Thanks to Matthew J. Cashman for the academic review of English. Finally, the authors would also to thank the Direccion General del Agua and INFRAECO for the cession of the trout data. The authors thank AEMET and UC by the data provided for this work (dataset Spain02).Muñoz Mas, R.; López Nicolás, AF.; Martinez-Capel, F.; Pulido-Velazquez, M. (2016). Shifts in the suitable habitat available for brown trout (Salmo trutta L.) under short-term climate change scenarios. Science of the Total Environment. 544:686-700. https://doi.org/10.1016/j.scitotenv.2015.11.14768670054

Experimentation at the interface of fluvial geomorphology, stream ecology and hydraulic engineering and the development of an effective, interdisciplinary river science

One ‘2020 vision’ for fluvial geomorphology is that it sits alongside stream ecology and hydraulic engineering as a key element of an integrated, interdisciplinary river science. A challenge to this vision is that scientists from these three communities may approach problems from different perspectives with different questions and have different methodological outlooks. Refining interdisciplinary methodology is important in this context, but raises a number of issues for geomorphologists, ecologists and engineers alike. In particular, we believe that it is important that there is greater dialogue about the nature of mutually-valued questions and the adoption of mutually-acceptable methods. As a contribution to this dialogue we examine the benefits and challenges of using physical experimentation in flume laboratories to ask interdisciplinary questions. Working in this arena presents the same challenges that experimental geomorphologists and engineers are familiar with (scaling up results, technical difficulties, realism) and some new ones including recognizing the importance of biological processes, identifying hydraulically meaningful biological groups, accommodating the singular behaviour of individuals and species, understanding biological as well as physical stimuli, and the husbandry and welfare of live organisms. These issues are illustrated using two examples from flume experiments designed (1) to understand how the movement behaviours of aquatic insects through the near-bed flow field of gravelly river beds may allow them to survive flood events, and (2) how an understanding of the way in which fish behaviours and swimming capability are affected by flow conditions around artificial structures can lead to the design of effective fish passages. In each case, an interdisciplinary approach has been of substantial mutual benefit and led to greater insights than discipline-specific work would have produced. Looking forward to 2020, several key challenges for experimentalists working on the interface of fluvial geomorphology, stream ecology and hydraulic engineering are identified

An Evaluation of the Spatial Configuration and Temporal Dynamics of Hydraulic Patches in Three UK Lowland Rivers.

Accurate characterisation of the hydraulic environment is a key step in describing hydromorphology at an ecologically relevant scale which has relevance to several aspects of river management, including monitoring river health, designing environmental flows and evaluating river rehabilitation measures. However, current hydraulic habitat quantification methods oversimplify the spatial heterogeneity of the hydraulic environment and do not explain or interpret the spatial arrangement of different habitat units sufficiently or define the dynamics of these shifting patterns. This research applied a novel numerical classification method and a landscape ecology framework to quantify the composition and configuration hydraulic patches in three UK lowland river reaches at five different flows. Five spatially coherent hydraulic patches, defined by the joint distribution of depth-velocity, were optimally delineated from hydraulic point data at each reach using the Gustafson-Kessel fuzzy clustering algorithm. Transitional zones between hydraulic patches occupied between 18- 30% and represent an application of the ecotone concept to the instream environment. Hydraulic patch diversity increased with discharge, peaking at high flow (Q38-Q22), suggesting that the provision of high flows is important for maximising hydraulic heterogeneity. The dominance of shallow, slow patches at low flow was gradually replaced by faster, deeper hydraulic patches at high flow illustrating the effect of discharge on the availability of different hydraulic patch types. The spatial arrangement of patches, quantified using a range of spatial metrics from the field of landscape ecology at two spatial scales (class and reachscape), was relatively invariant to changes in discharge suggesting that the configuration of the hydraulic patch mosaic is determined by channel morphology and remains stable between channel forming discharges. The majority of hydraulic patch types occurred in relatively fixed locations in the channel, moving relatively small distances as discharge increased, associated with the gradual expansion or contraction of patch area. The results suggest that sub-bankfull flow variations will primarily affect the composition rather than the configuration of hydraulic patches, however large fluctuations are likely to result in high rates of patch turnover (change in location), with potential implications for instream biota. The hydraulic patch/transition zone model of the hydraulic environment provides a new approach for exploring the link between physical and biological heterogeneity in the instream environment, including the role of instream ecotones. Whilst the application of numerical classification is currently limited by the large hydraulic data requirement, future advances in remote-sensing technology and hydrodynamic modelling are likely to widen its iii applicability at a range of spatial scales. The results highlight the need for further research on the ecological significance of hydraulic patches and transition zones and ecological sensitivity to changes in hydraulic patch configuration. Wider application of the landscape ecology approach to hydraulic habitat assessment in different reach types is recommended to improve understanding of the links between geomorphic and hydraulic diversity