Habitat Simulation Research Articles

Invasion and potential impacts of the first alien carnivore in China: American minks (<italic>Neovison vison</italic>) in Altai region, Xinjiang

American minks ( Neovison vison ), which cause great impacts on local small and median sized animals through direct predation and diseases tramission, had been characterized as an invasive species worldwide. As well-known fur animals, American minks were introduced to Europe in early 20th century, and to China in mid-20th century. American minks spread nearly entire Europe soon after escaping from fur farms in European countries, and they had already established naturalized population in northern Altai Mountain in Russia for years. Northern Altai Mountain is one of the main distribution areas of American minks in Russia. In recent years, American minks were reported in southern Altai mountains (Altai region, or Chinese Altai) in Xinjiang, China. American minks occurred in forest parks and national nature reserves in Altai region. Earlier records in China were misidentified as European minks or both of them. Based on field survey and photo identification, we confirmed that all these records were belong to American minks. Although American minks had been imported to China for over half a century, now they were found in wild in north-western China instead of eastern China, where had more mink farms. Thus American minks found in Chinese Altai may be border-crossing invaders. Through field survey and investigation, American minks were not rare in the forest parks and nature reserves of Chinese Altai region, thus we suggested that American mink had already established populations in China. We discussed the potential impacts of American minks invasion in China through habitat simulation, potential prey and competing species, and wildlife diseases. We discussed the current status of otters in China, which had similar niches to minks. Using MaxEnt model for habitats simulation at global scales, we predicted climate-suitable areas for American minks. We find that coastal regions of North America, south tip of South America, Europe, Eastern Asia, North Africa, South Eastern Australia and New Zealand harbor highly suitable habitats of American minks. All these coastal areas should be exceptionally precautious for live minks transport. In addition, mountains of Central Asia are the only inland highly suitable habitats of American minks. Central Asia harbors plentiful endemic fishes, and should be precautious for American minks invasion. In China, Chinese Altai and middle to lower reaches of Yangtze River are highly suitable habitats for American minks, where otters are almost disappeared. As China’s first alien carnivore, American minks will impose great predation pressures on endemic waterfowls and fishes, and will have impact on China’s endangered otters and other mustelids. All three major minks epidemic diseases: canine distemper, Aleutian disease and mink viral enteritis had already have outbreak records in Chinese mink farms, and theses diseases had been proven to transmit to wildlife. In addition, China the has largest mink farming industry of the world. Therefore, besides controlling border-crossing invasion, eco-security assessments should be strengthened in domestic mink farms.

ONE- AND TWO-DIMENSIONAL ECOHYDRAULIC MODELING OF FORMOSO RIVER (MG)

ABSTRACT The objective of this study was to compare ecohydrological simulations from a one-dimensional model (PHABSIM - Physical Habitat Simulation System) and a two-dimensional model (River2D) in order to indicate a reliable tool that could be used to determine public policies for the sustainable management of the water resources of the FormosoRiver basin(MG). The results from the calibration of hydraulic variables, namely, water depth and velocity, as well as habitat predictions for three fish species of the river were compared. The results showed that River 2D was best suited to simulate ecohydrological features for the studied river stretch. Although PHABSIM presented a better fit of the hydraulic variables at the calibration process, the use of only three monitoring cross sections to compose the biotic model database compromised its habitat modeling. PHABSIM model was not able to accurately assess the actual characteristics of the physical habitat in the segments of the river located between the monitoring cross sections.

Why It Is Time to Put PHABSIM Out to Pasture

The Physical Habitat Simulation System (PHABSIM) was developed in the 1970s to fill an important void in instream flow assessment. Although considerable progress has been made in ecological modeling since the 1970s, there has been little change in instream flow assessment. PHABSIM has two general problems. First, PHABSIM is a habitat selection model (HSM)—but not a good one: it no longer conforms to standard practices in the wider fields of ecological and wildlife modeling, especially by using inappropriate spatial scales and outdated methods for modeling habitat preference and by producing output that lacks clear meaning. Second, HSMs, in general, are not well suited for many instream flow decisions. HSMs cannot consider variation in flow over time, whereas dynamic flow regimes are now considered essential, and HSMs do not make testable predictions of fish population responses. Alternatives to PHABSIM include analyses based on explicit understanding of species ecology, individual‐based models, and more powerful modern habitat selection modeling methods.

The role of 3D-hydraulics in habitat modelling of hydropeaking events

One way to study ecological implications induced by hydropeaking represents the coupling of hydrodynamic models with habitat suitability models, in which hydrodynamic parameters are typically used to describe the physical habitat of indicator species. This article discusses the differences in habitat suitability assessment between 2D and 3D CFD modelling as input for the habitat simulation tool CASiMiR. In the first part of the article, the accuracy of the hydraulic model is evaluated by comparing the model results with laboratory (model of a laboratory channel with erodible bed) and field measurements (Valsura River, Bolzano, Italy). In the second part, the habitat suitability for the Valsura River case study (affected by hydropeaking), is analyzed comparing different approaches for the reconstruction of the velocity field (depth-averaged velocities from 2D modelling, bottom velocity field reconstruction with log-law approach from 2D modelling and bottom velocity field from 3D modelling). The results show that the habitat suitability index (HSI) using 2D or 3D hydrodynamic models can be significantly different. These differences can be ascribed to a higher capability to depict the features of the flow field with highly variable and heterogeneous boundary conditions and to the possibility to simulate the near bed hydrodynamic parameters, which are relevant for certain target species. In particular, the HSI-values using 3D hydraulics lead to larger areas of highly suitable habitats compared to 2D simulations. Moreover, considering the entire flow range of hydropeaking events, the habitat simulations with bottom flow velocities from 3D modelling provide suitable habitats over the entire flow range representing the availability of stable suitable habitats, while the habitat availability of 2D modelled flow velocity is continuously decreasing with increasing flow rates.

Developing Bioenergetic‐Based Habitat Suitability Curves for Instream Flow Models

AbstractInstream flow models link a physical habitat model that predicts flow‐related changes in hydraulics to a biological model that predicts the response of fish to altered velocity and depth. Habitat suitability curves (HSCs) based on frequency of habitat use (fish occurrence relative to available habitat) remain the most widely used biological models in habitat simulations. However, in some contexts fish density may be a poor indicator of habitat quality, leading to biased predictions of optimal flow. We explore the use of bioenergetics to derive mechanistic HSCs based on the fundamental energetics of habitat use. Using flow‐related changes in production of Coho SalmonOncorhynchus kisutchsmolt as reference data to evaluate model predictions, we found that bioenergetic‐based HSCs matched the validation data better than frequency‐based HSCs, which systematically underestimated optimal flows. However, biases remained using bioenergetic HSCs, suggesting that habitat suitability may not be independent of discharge as is often assumed. Declining invertebrate drift concentration, increasing temperature, and density dependence of growth at low flows are potential mechanisms of flow‐related declines in habitat suitability; measuring these effects and incorporating them into flow models is an important step in further improving model predictions, particularly at low flows.Received December 3, 2015; accepted May 11, 2016

Ecological Regime versus Minimum Environmental Flow:Comparison of Results for a River in a Semi Mediterranean Region

Maintaining Environmental Flow (EF) plays a critical role in protecting rivers and their ecosystems. Because of shortage of data and limited financial resources in developing countries, there is a tendency to use simple hydrologic methods against comprehensive EF assessment methods. In this research, two most common hydrologic methods (Tennant and Q95) were compared with a habitat simulation method (PHABSIM) under the condition of data shortage. It was concluded that while the results of habitat simulation method even using imprecise input data were justified, the impacts of implementing EF discharges of the two hydrologic methods on the ecosystem might be irreversible. It was found that the Tennant and Q95 methods led to dramatically low discharges as fixed minimum environmental flows, while habitat simulation method gave an acceptable ecological regime. In the absence of ecological data and after deciding on the target species in a case study in the southern part of the Caspian Sea, a special Delphi technique was employed for preparing the suitability data. For enhancing the PHABSIM hydraulic module results, HEC-RAS was implemented for hydraulic simulation and then with a simple modification on average velocity, the cross-sectional velocity distribution for deriving the Weighted Usable Area (WUA) was generated. It was found that this method along with maintaining high flows in the river preserved Mean Annual Flow (MAF) during wet months and preserved Mean Annual Low Flow (MALF) during dry months which is equal to maintaining Environmental Flow Requirement (EFR) in such a way that provides the river with an ecological regime near its historical one and guarantees river health.

Minimum instream flow requirement for the water-reduction section of diversion-type hydropower station: a case study of the Zagunao River, China

Diversion-type hydroelectric exploitation can reduce instream flow and destroy river ecosystem continuity. Maintaining instream flow is considered an effective way to remediate the damages. The Physical Habitat Simulation (PHABSIM) system still probably remains as the most widespread habitat method used to establish instream flow standards or to link habitat variations with fish population dynamics. This study applies the PHABSIM models, which create a habitat–flow relationship, describing the physical habitat suitability of alternative instream flow releases. Selecting the water-reduction section of the Sangping Power Station on the Zagunao River as the research object, the hydraulic pressure at a cross section was obtained through habitat simulation. The Cyprinidae family of fish, dominant in this region, was targeted using velocity and depth suitability curves. The quantitative relationship between flow and suitable habitat area was established, with the minimum instream flow of the study area calculated as 30.0 m3/s, according to the weighted usable area–flow curve. The minimum instream flow of the study area was also estimated through common hydrologic and hydraulic methods. The resulting comparison indicated that the habitat simulation model achieved very similar results to those of the wetted perimeter method and achieved between “good” and “very good” levels using the Tennant method. The result indicates that the PHABSIM model is useful for optimizing the flow release schemes of hydropower stations in southwestern China. Moreover, it helps to analyze trade-offs between human and environmental water needs, resulting in solutions that minimize ecological integrity disturbances.

A review of environmental flow assessment: methodologies and application in the Qianhe River

Environmental flow is of great significance for maintenance of ecological services in the riverine ecosystem. The paper reviews present methodologies for environmental flow assessment on the basis of three classifications, including the Hydrological Index Methodologies, the Hydraulic Rating Methodologies and the Habitat Simulation Methodologies. Both advantages and disadvantages of each classification are fully analysed, as well as applicable conditions. Moreover, representative methods of different classifications are applied to prescribe environmental flow in the Qianhe River of north China with consideration of hydrological series, hydraulic characteristics and habitat suitability of targeted species. The results of environment flow by the Montana Method, Wetted Perimeter Method and Physical Habitat Simulation System are 1.23 m3/s, 2.07 m3/s and 0.52 m3/s for the Qianyang section in middle reach of the Qianhe River. In view of seasonal variation of the Qianhe River, the paper recommends 1.23 m3/s as the minimum runoff in the dry season and 2.07 m3/s in the wet season. For further improvement of environmental flow assessment, studies of quantitative correspondence relationship between each component of instream flow and its ecological functions of riverine ecosystem, and the development of Holistic Methodologies by combination of various methodologies and multi-disciplinary information have great potential.

Adapting the operation of cascaded reservoirs on Yuan River for fish habitat conservation

To alleviate the negative impacts on ecosystem caused by cascaded development of Yuan River, this study quantified the ecological requirements and incorporated them into the cascaded reservoir operating schemes to provide the streamflow that balances fish habitat protection and hydropower generation. Physical habitat simulation model is proposed to simulate the relationship between streamflow and physical habitat for various life stages of Cyprinus rubrofuscus Lacépède and Bagarius rutilus Ng & Kottelat, and to determine the ecological requirement as a discharge range associated with the upper area of a certain proportion of maximum Weighted Usable Areas (WUA). Then the optimal operation model of cascaded reservoirs is established. Maintaining over 70% of maximum WUA as an example, the optimization technique could increase the hydropower generation of cascaded reservoirs by 3.60%, 1.93% and 4.19%, and also improve the ecological conditions by increasing the WUAs by 11.3%, 17.9% and 16.2% for Section A and 7.4%, 12.4% and 14.4% for Section B under wet, normal and dry conditions, respectively. Furthermore, the trade-offs between hydropower production and fish habitat conservation are discussed. The optimal compromises were identified at the knick points in the established relations where 50%–70% of maximum WUA are conserved at a cost of 11.72–52.11 billion kWh (1.8%–8.4%) power generation loss.

Ecohydraulics exemplifies the emerging “paradigm of the interdisciplines”

ABSTRACTThe basic premise underlying ecohydraulics is deceptively simple: create a new discipline focused on the effects of water movement in aquatic ecosystems by melding principles of aquatic ecology (including aspects of fluvial geomorphology) and engineering hydraulics. However, advancing ecohydraulics as a synthetic, organized field of study is challenging because hydraulic engineers and ecologists (1) study processes that differ substantially in spatial and/or temporal scale; (2) have very different approaches to modelling; (3) utilize different sets of mathematical formulations, concepts, and assumptions; and (4) address problems with vastly different patterns of complexity and uncertainty. The differences between engineering and ecology must be reconciled within a set of concepts and practices applicable to ecohydraulics. This reconciliation is essential if ecohydraulics is to achieve the scientific esteem of its parent disciplines. First, we review how the competing paradigms of determinism and empiricism structure engineering and ecology, respectively. We then derive two guiding principles that facilitate the integration of ecology and hydraulics, the single reference framework and the multiple reference framework guiding principles. Third, we provide illustrative examples of these principles using a simple hydraulic fish habitat analysis based on physical habitat simulation (PHABSIM) system of the instream flow incremental methodology (IFIM) and a detailed fish movement model using Eulerian–Lagrangian–Agent methods (ELAMs). Based on these examples, we develop insights and conclusions to guide further advances in ecohydraulics and, perhaps even serve as a template to aid development of other interdisciplinary fields.

Can Weighted Useable Area Predict Flow Requirements of Drift‐Feeding Salmonids? Comparison with a Net Rate of Energy Intake Model Incorporating Drift–Flow Processes

AbstractWe compared a process‐based invertebrate drift and drift‐feeding net rate of energy intake (NREI) model and a traditional hydraulic‐habitat model (using the RHYHABSIM [River Hydraulics and Habitat Simulation] software program) for predicting the flow requirements of 52‐cm Brown Trout Salmo trutta in a New Zealand river. Brown Trout abundance predicted by the NREI model for the constant drift concentration–flow scenarios were asymptotic or linear, depending on drift concentration, increasing through the mean annual low flow (MALF; 17 m3/s). However, drift concentration increased with flow, consistent with passive entrainment. The predicted fish abundance–flow relationship based on flow‐varying drift concentration increased logistically, and more steeply, with flow through the MALF and beyond. Predictions for the relationship between weighted useable area (WUA) and flow were made for three sets of drift‐feeding habitat suitability criteria (HSC) developed on three midsized and one large New Zealand river (flow at sampling was 2.8–4.6 m3/s and ~100 m3/s, respectively) and the South Platte River, Colorado (flow at sampling, 7–18 m3/s). The midsized‐river HSC ascribe lower suitability to water velocities > 0.6 m/s. They predicted WUA peaking at 10–11 m3/s, well below the MALF. The WUA–flow relationships for the two large‐river HSC were asymptotic at about 22 m3/s. Overall, WUA appears to underestimate the flow needs of drift‐feeding salmonids. The NREI model showed that assessing flow needs of drift‐feeding fish is more complex than interpreting a WUA–flow relationship based only on physical habitat suitability. The relationship between predicted fish abundance and flow is an emergent property of flow‐dependent drift‐foraging dynamics interacting with flow‐dependent drift concentration and drift flux, local depletion of drift by feeding fish, and flow‐related replenishment of drift from the bed and dispersion. It is time that the principles and predictions of drift–NREI models influence assessments of habitat capacity and instream flow needs of drift‐feeding fish.Received April 10, 2015; accepted November 10, 2015 Published online April 27, 2016

Generalized additive and fuzzy models in environmental flow assessment: A comparison employing the West Balkan trout (Salmo farioides; Karaman, 1938)

Human activities have altered flow regimes resulting in increased pressures and threats on river biota. Physical habitat simulation has been established as a standard approach among the methods for Environmental Flow Assessment (EFA). Traditionally, in EFA, univariate habitat suitability curves have been used to evaluate the habitat suitability at the microhabitat scale whereas Generalized Additive Models (GAMs) and fuzzy logic are considered the most common multivariate approaches to do so. The assessment of the habitat suitability for three size classes of the West Balkan trout (Salmo farioides; Karaman, 1938) inferred with these multivariate approaches was compared at three different levels. First the modelled patterns of habitat selection were compared by developing partial dependence plots. Then, the habitat assessment was spatially explicitly compared by calculating the fuzzy kappa statistic and finally, the habitat quantity and quality was compared broadly and at relevant flows under a hypothetical flow regulation, based on the Weighted Usable Area (WUA) vs. flow curves. The GAMs were slightly more accurate and the WUA-flow curves demonstrated that they were more optimistic in the habitat assessment with larger areas assessed with low to intermediate suitability (0.2–0.6). Nevertheless, both approaches coincided in the habitat assessment (the optimal areas were spatially coincident) and in the modelled patterns of habitat selection; large trout selected microhabitats with low flow velocity, large depth, coarse substrate and abundant cover. Medium sized trout selected microhabitats with low flow velocity, middle-to-large depth, any kind of substrate but bedrock and some elements of cover. Finally small trout selected microhabitats with low flow velocity, small depth, and light cover only avoiding bedrock substrate. Furthermore, both approaches also rendered similar WUA-flow curves and coincided in the predicted increases and decreases of the WUA under the hypothetical flow regulation. Although on an equal footing, GAMs performed slightly better, they do not automatically account for variables interactions. Conversely, fuzzy models do so and can be easily modified by experts to include new insights or to cover a wider range of environmental conditions. Therefore, as a consequence of the agreement between both approaches, we would advocate for combinations of GAMs and fuzzy models in fish-based EFA.

Estimation of optimal ecological flowrates for fish habitats in a nature-like fishway of a large river

Fishways are constructed to provide longitudinal connectivity of streams or rivers where their flow has been altered by in-stream structures such as dams or weirs. Nature-like fishways have an additional function of providing fish habitats. In the study, we estimated the role of a nature-like fishway (length: 700 m, slope: 1/100) for fish habitat by using two dominant species in the Sangju Weir, Nakdong River, to calculate the optimal ecological flow rate using Physical HABitat SIMulation (PHABSIM). To identify the dominant species that used the fishway, we conducted trap monitoring from August to November 2012 at the fishway exit. The dominant species were Zacco platypus and Opsariichthys uncirostric amurensis with a relative abundance of 62.1% and 35.9%, respectively. Optimal habitat suitability indices (HSIs) for Z. platypus and O. u. amurensis were calculated as 0.6-0.8 m/s (water velocity) and 0.2-0.4 m (water depth), and 0.5-0.7 m/s (water velocity) and 0.1-0.3 m (water depth), respectively. The optimal ecological flow rates (OEFs) for Z. platypus and O. u. amurensis were 1.6 and 1.7 cubic meter per second (CMS), respectively. The results of the study can be used in a management plan to increase the habitat function of nature-like fishways in the Sangju Weir. This methodology can be utilized as an appropriate tool that can determine the habitat function of all nature-like fishways.

PlanHab: the combined and separate effects of 16 days of bed rest and normobaric hypoxic confinement on circulating lipids and indices of insulin sensitivity in healthy men.

PlanHab is a planetary habitat simulation study. The atmosphere within future space habitats is anticipated to have reduced Po2, but information is scarce as to how physiological systems may respond to combined exposure to moderate hypoxia and reduced gravity. This study investigated, using a randomized-crossover design, how insulin sensitivity, glucose tolerance, and circulating lipids were affected by 16 days of horizontal bed rest in normobaric normoxia [NBR: FiO2 = 0.209; PiO2 = 133.1 (0.3) mmHg], horizontal bed rest in normobaric hypoxia [HBR: FiO2 = 0.141 (0.004); PiO2 = 90.0 (0.4) mmHg], and confinement in normobaric hypoxia combined with daily moderate intensity exercise (HAMB). A mixed-meal tolerance test, with arterialized-venous blood sampling, was performed in 11 healthy, nonobese men (25-45 yr) before (V1) and on the morning ofday 17of each intervention (V2). Postprandial glucose and c-peptide response were increased at V2 of both bed rest interventions (P< 0.05 in each case), with c-peptide:insulin ratio higher at V2 in HAMB and HBR, both in the fed and fasted state (P< 0.005 in each case). Fasting total cholesterol was reduced at V2 in HAMB [-0.47 (0.36) mmol/l;P< 0.005] and HBR [-0.55 (0.41) mmol/l;P< 0.005]. Fasting HDL was lower at V2 in all interventions, with the reduction observed in HBR [-0.30 (0.21) mmol/l] greater than that measured in HAMB [-0.13 (0.14) mmol/l;P< 0.005] and NBR [-0.17 (0.15) mmol/l;P< 0.05]. Hypoxia did not alter the adverse effects of bed rest on insulin sensitivity and glucose tolerance but appeared to increase insulin clearance. The negative effect of bed rest on HDL was compounded in hypoxia, which may have implications for long-term health of those living in future space habitats.

댐 하류 하천에서 하상변동 모델을 이용한 어류 물리서식처 변화 모의

This study investigated the impact of the morphological change on a physical fish habitat in the downstream reach of a dam using long-term mobile bed simulation. The quasi-steady model was used for hydraulic simulation and the habitat suitability index model was applied for physical habitat simulation. For simulating long-term morphological change of the stream bed, The Exner equation was used. Sorting of bed material was also considered. The results of simulation showed that erosion and armoring process occurred in a reach downstream of the dam and change of physical habitat for Zacco platypus followed. These results indicate that channel morphology and substrate conditions effected the physical habitat for considering long-term investigation.

Physical habitat simulation system (PHABSIM) 을 이용한 금강의 두드럭조개 (Lamprotula coreana) 서식지 평가

본 조사는 2013년 6월부터 8월까지 금강 상류에서 멸종위기야생생물 I급인 두드럭조개 (Lamprotula coreana)의 서식지를 조사하였다. 서식지 평가를 위하여 하천의 물리적 구조인 여울, 소 및 유수역이 모두 포함된 다양한 서식환경에서 서식상태를 조사하였으며, 하천단면, 수심, 유속, 하상재료 및 서식지 유형 등을 현장에서 측정 하였다. 서식 확인된 두드럭조개는 크기, 무게 및 연령을 기록하고 서식지에 재살포하였고, 서식지적합도지수 (Habitat suitability index, HSI)와 PHABSIM (physical habitat simulation system)에 의한 최적 생태유량 산정을 위하여, 각각의 채집 장소에서 수심, 유속 및 하상재료 등을 기록하였다. 서식지 평가는 수위, 유량 및 하천단면의 현장조사 결과와 두드럭조개의 HSI를 PHABSIM에 적용하여 가용서식지면적 (weighted usable area, WUA)과 유량의 관계 곡선을 작성하였다. 금강 상류에서 채집된 두드럭조개는 각장 <TEX>$73.1{\pm}18.4mm$</TEX> 및 전중 <TEX>$131.6{\pm}72.3g$</TEX> 이었으며, 연령은 2-7년생까지 서식하는 것으로 확인되었다. 두드럭조개의 HSI는 수심 0.4-0.5 m, 유속 0.3-0.5 m/s, 하상재료는 모래-호박돌로 나타났다. PHABSIM에 의해 모의된 최적유량은 2.1 cms였으며, WUA는 <TEX>$3,730m^2$</TEX>/1000 m로 나타났다. 두드럭조개의 서식지 평가 결과는 최근 각종 하천 공사 및 생태적 교란 등으로 서식 범위가 감소하고 있는 시점에서 서식지 복원 및 관리를 위한 기초자료로 활용될 수 있을 것이다. This study sampled endangered species, Lamprotula coreana, and surveyed its habitat at the Guem River with three times from June to August 2013. To assess the habitat, this study conducted field survey considering diverse physical conditions of stream, such as pool, run and riffle, and measured transect, water depth, water velocity, substrate structure, and habitat type. When L. coreana collected, length, weight and age were measured. Water velocity, water depth and substrate structure were recorded to develop HSI (habitat suitability index) and performed PHABSIM (physical habitat simulation) to estimate the optimum flow discharge. Water level, flow discharge and transect data were used for habitat assessment, and PHABSIM was applied to calculate WUA (weighed usable area). Shell length was <TEX>$73.1{\pm}18.4mm$</TEX> (28.5-102.0 mm), shell weight was <TEX>$131.6{\pm}72.3g$</TEX> (28.0-281.0 g) and age was two to seven years from L. coreana collected at the upstream of the Guem River. Developed HSI indicated that the optimal habitat for L. coreana was 0.4-0.5 m for water depth, 0.3-0.5 m/s for water velocity and sand to boulder for substrate structure. The optimum ecological flow discharge for L. coreana was 2.1 cms and WUA was <TEX>$3,730m^2$</TEX>/1000 m by the result of PHABSIM. Recently, river construction work and habitat disturbance have caused negative impact on the distribution of L. coreana. The result of this study would provide fundamental data for habitat restoration and management of L. coreana.

Application of the physical habitat simulation for fish species to assess environmental flows in an Atlantic Forest Stream in South-eastern Brazil

ABSTRACT The physical habitat simulation sub-routine of the Instream Flow Incremental Methodology (IFIM) uses hydraulic modeling and suitability indices of target fish species to predict how differences in-stream flows affect the microhabitat occupation by fish species. This habitat modelling approach was adopted to assess the ecological effects of running flows on three neotropical fish species of different orders (Bryconamericus ornaticeps , Ancistrus multispinis and Geophagus brasiliensis ).The study encompassed two reaches of an Atlantic Forest stream in Southeastern Brazil where topographic and hydraulic (depth, velocity and type of substrate) characteristics were measured to implement one-dimensional hydraulic simulation. Sub aquatic observation of fish was performed to collect data on microhabitat use and these data were used to develop habitat suitability curves that were used in the habitat simulation to obtain the habitat suitability index (HSI) and weighted usable area (WUA) versus flow curves. Upon these curves minimum and optimum environmental flows for the target fish species were proposed. Bryconamericus ornaticeps and A. multispinis selected microhabitats around 0.6 m depth, whereas G. brasiliensis showed a wider suitable range (0.35-0.9 m). All the three species were mainly observed in microhabitat with low flow velocity (0.1 m/s). Bryconamericus ornaticeps selected more frequently coarse substrate (e.g. boulders) but it appeared also over sandy substrate, whereas A. multispinis and G. brasiliensis selected preferably boulders. The range of 0.65-0.85 m3/s was found as the optimum to meet the needs of the three fish species. Our results agree with the necessary objective information to perform grounded management actions in the frame of a management program aiming at ecosystem conservation. Thereby it can be considered a successful pilot study in environmental flow assessment in an Atlantic Forest stream of Brazil.

Projecting the impact of climatic warming on coldwater fish habitat in Lake Jingpo

Climate warming would have a great impact on the water temperature and dissolved oxygen (DO) distribution of lakes in cold regions. It can have an effect on fish populations. To evaluate the effect of climatic change on coldwater fish habitat in cold regions of China, a fish habitat simulation model was developed. The fish habitat simulation model was developed based on the output of A vertical year-round water temperature and dissolved oxygen model. Lake Jingpo in Northeast China was chosen as the representive lake. The coldwater stenothermal fish called Hucho taimen was selected as the indicator species. Constant Values Method and oxythermal habitat parameter method were applied to identify the refuge habitat. The simulation results show that under the future climate scenarios, the uninhabitable space in winter due to low dissolved oxygen in hypolimnion will decrease, the uninhabitable space in summer due to high temperature in epilimnion will expand. Total habitat depth in summer is projected to decrease up to 60%-90%, which means high probability of summer kill. It is projected that multi-year average value of ATDO3 vb (highest average daily TDO3 over variable benchmark period) will have an increase of about 2.5℃, which means Hucho taimen juvenile survival rate will decrease about 35%. In the extreme warm year, the Hucho taimen juvenile survival rate will decrease to 9.0%. The oxythermal habitat parameter method is generic and can be applied to other lakes and reservoirs in Northeast China to identify and compare the refuge habitat of coldwater fishes.

Effects of Future Climate Change on a River Habitat in an Italian Alpine Catchment

AbstractThe impact of prospective climate change on the hydrological and ecological status of the mountain stretch of the Serio river (ca. 300 km2) in the Northern Italian Alps was investigated. A hydrological model was used to mimic theflow regime, and experimental suitability curves were used to assess weighted usable area (WUA) for brown trout (Salmo trutta) in different stages (adult, young, and spawning), and four macroinvertebrates families (Leuctridae, Heptageniidae, Limnephilidae, and Limoniidae). Discharge-WUA curves were obtained using instream flow incremental methodology/physical habitat simulation system (IFIM-PHABSIM), and a seasonal WUA assessment was carried out. The future (until 2100) hydrological cycle was projected using outputs from two general circulation models from Assessment Report 5 of the Intergovernmental Panel on Climate Change (IPCC). The results display a potential for a large flow decrease yearly, until −60% at 2050 and −56% at 2090. Spring melt peaks will be largely dampe...

Transferability of Monitoring Data from Neighboring Streams in a Physical Habitat Simulation

Habitat simulation models heavily rely on monitoring data, which can have serious effects on the success of a physical habitat simulation. However, if data monitored in a study reach are not available or insufficient, then data from neighboring streams are commonly used. The problem is that the impact of using data from neighboring streams has rarely been studied before. Motivated by this, we report herein on an investigation of the transferability of data from neighboring streams in a physical habitat simulation. The study area is a 2.5 km long reach located downstream from a dam in the Dal River, Korea. Zacco platypus was selected as the target fish for the physical habitat simulation. Monitoring data for the Dal River and three neighboring streams were obtained. First, similarities in the data related to channel geometry and in the observed distribution of the target species were examined. Principal Component Analysis (PCA) was also carried out to see the characteristics of the habitat use of the target species. Habitat Suitability Curves (HSCs) were constructed using the Gene Expression Programming (GEP) model, and improved Generalized Habitat Suitability Curves (GHSCs) were proposed. The physical habitat simulations were then performed. The Composite Suitability Index (CSI) distributions were predicted, and the impact of using data from the neighboring streams was investigated. The results indicated that the use of data from a neighboring stream even in the same watershed can result in large errors in the prediction of CSI. The physical habitat simulation with the improved GHSCs was found to best predict the CSI.