Modelling habitat requirement of European fishes: do species have similar responses to local and regional environmental constraints?

2005 ◽  
Vol 62 (1) ◽  
pp. 163-173 ◽  
Author(s):  
D Pont ◽  
B Hugueny ◽  
T Oberdorff
Keyword(s):  
Salmo Trutta ◽  
Explanatory Power ◽  
Regional Scale ◽  
Drainage Area ◽  
Environmental Constraints ◽  
Data Set ◽  
Continuous Increase ◽  
Cottus Gobio ◽  
Species Response ◽  
Barbus Barbus

To test the hypothesis that different species have similar responses to local and regional environmental constraints, we modelled the occurrences of 13 species using a data set of 413 undisturbed river reaches. Three environmental descriptors were considered at the local scale (river slope, river width, and upstream drainage area) and three at the regional scale (mean annual and mean range air temperature and basin unit). Using multiple logistic regression modelling techniques, we correctly predicted the occurrence of 11 of the 13 retained species. The hierarchical partitioning analysis that we used allowed us to jointly consider all possible models in a multiple regression setting and to evaluate the independent explanatory power of each of our five environmental variables. We reject the hypothesis of a common species response to the environmental constraints. Species inhabiting upstream river reaches (bullhead (Cottus gobio), brown trout (Salmo trutta), minnow (Phoxinus phoxinus), and stone loach (Barbatula barbatula)) are more sensitive to basin unit. All species representative of downstream areas (barbel (Barbus barbus), dace (Leuciscus leuciscus), chub (Leuciscus cephalus), gudgeon (Gobio gobio), roach (Rutilus rutilus), bleak (Alburnus alburnus), and perch (Perca fluviatilis)) exhibit a positive continuous response to the drainage area, in agreement with the view of a continuous increase of local richness downstream. River slope is an important variable for all species. Main species habitat requirements are discussed for each species.

Colonization and establishment of Pomphorhynchus laevis (Acanthocephala) in an isolated English river

1996 ◽  
Vol 70 (1) ◽  
pp. 27-31 ◽  
Author(s):  
C.R. Kennedy
Keyword(s):  
Salmo Trutta ◽  
Anguilla Anguilla ◽  
Pomphorhynchus Laevis ◽  
Cottus Gobio ◽  
Barbus Barbus ◽  
New Localities ◽  
Present Distribution ◽  
Gravid Females ◽  
Successful Colonization ◽  
Preferred Hosts

AbstractThe successful colonization, establishment and spread of Pomphorhynchus laevis in a small, isolated, Devon river 128 km from the parasite's nearest focus in Dorset was followed over 11 years from 1985. The parasite was first detected in Anguilla anguilla and Platichthys flesus in 1988: by 1995 it had attained prevalence levels of 22.6% in A. anguilla and 43.6% in P. flesus and also occurred in 100% Salmo trutta, 50% Cottus gobio and Noemacheilus barbatulus. As judged by prevalence, abundance, proportion of females gravid and weight of gravid females, S. trutta was the preferred definitive host although C. gobio was a suitable host and may play a role in cycling the parasite: the other three species were unsuitable hosts. The intermediate host was the freshwater Gammarus pulex: the euryhaline G. zaddachi was not infected. On biological grounds, the P. laevis could be assigned to the English freshwater strain and was almost certainly introduced to the river by anthropochore stocking of S. trutta from a Dorset hatchery. The findings demonstrate conclusively that the English strain of P. laevis can colonize and establish in a new locality from which Leuciscus cephalus and Barbus barbus, its normal preferred hosts, are absent and use S. trutta instead. The results also confirm that P. laevis is a poor natural colonizer and appears always to be introduced to new localities by anthropochore transfers of fish. The implications of these conclusions for understanding the present distribution of P. laevis are discussed and it is considered that they provide direct evidence in support of the hypothesis that P. laevis was introduced to Ireland from England and subsequently adapted to use of S. trutta and G. duebeni there.

scholarly journals Integration of Constructed Floodplain Ponds into Nature-Like Fish Passes Supports Fish Diversity in a Heavily Modified Water Body

Water ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1018
Author(s):  
Joachim Pander ◽  
Christoffer Nagel ◽  
Juergen Geist
Keyword(s):  
Salmo Trutta ◽  
Fish Community ◽  
Habitat Characteristics ◽  
Fish Diversity ◽  
Target Species ◽  
Habitat Types ◽  
Cottus Gobio ◽  
Barbus Barbus ◽  
Main River ◽  
Important Habitat

Fish passes facilitate fish movement in fragmented river systems, yet they can also provide important habitat functions. This study investigated the fish community composition of different constructed habitat types (fluvial habitats, floodplain ponds) within fish passes in relation to habitat characteristics in order to deduce recommendations for fish-friendly designs of such structures. Fish community structures within passes differed significantly from those in the main river, comprising a high number of rheophilic species in fluvial habitats (Thymallus thymallus, Hucho hucho, Salmo trutta, Cottus gobio, Chondrostoma nasus, and Barbus barbus), and of stagnophilic species in floodplain ponds (Rhodeus amarus, Scardinius erythrophthalmus, Misgurnus bipartitus, and Tinca tinca). During summer, floodplain ponds also provided important juvenile habitats for the target species C. nasus and B. barbus. Differences between the two habitat types in fish abundance were mostly explained by differences in macrophyte coverage, gravel, boulders, temperature, and current speed. The findings of this study stress the important habitat functions of fish passes. They also suggest that integration of diverse habitat structures, especially of currently hardly considered constructed floodplain ponds into fish passes, can greatly enhance their fish communities and contribute to the restoration of several declining target species of conservation.

scholarly journals Coupling of regional geophysics and local soil-structure models in the EQSIM fault-to-structure earthquake simulation framework

2021 ◽  
pp. 109434202110191
Author(s):  
David McCallen ◽  
Houjun Tang ◽  
Suiwen Wu ◽  
Eric Eckert ◽  
Junfei Huang ◽  
...  
Keyword(s):  
Soil Structure ◽  
Ground Motions ◽  
Regional Scale ◽  
Historical Earthquakes ◽  
Department Of Energy ◽  
Simulation Framework ◽  
Data Set ◽  
Major Barrier ◽  
Local Soil ◽  
Computational Workflow

Accurate understanding and quantification of the risk to critical infrastructure posed by future large earthquakes continues to be a very challenging problem. Earthquake phenomena are quite complex and traditional approaches to predicting ground motions for future earthquake events have historically been empirically based whereby measured ground motion data from historical earthquakes are homogenized into a common data set and the ground motions for future postulated earthquakes are probabilistically derived based on the historical observations. This procedure has recognized significant limitations, principally due to the fact that earthquake ground motions tend to be dictated by the particular earthquake fault rupture and geologic conditions at a given site and are thus very site-specific. Historical earthquakes recorded at different locations are often only marginally representative. There has been strong and increasing interest in utilizing large-scale, physics-based regional simulations to advance the ability to accurately predict ground motions and associated infrastructure response. However, the computational requirements for simulations at frequencies of engineering interest have proven a major barrier to employing regional scale simulations. In a U.S. Department of Energy Exascale Computing Initiative project, the EQSIM application development is underway to create a framework for fault-to-structure simulations. This framework is being prepared to exploit emerging exascale platforms in order to overcome computational limitations. This article presents the essential methodology and computational workflow employed in EQSIM to couple regional-scale geophysics models with local soil-structure models to achieve a fully integrated, complete fault-to-structure simulation framework. The computational workflow, accuracy and performance of the coupling methodology are illustrated through example fault-to-structure simulations.

scholarly journals Standard geomagnetic observatory data in tectonomagnetism: case study related to the M 5.7 Timisoara, Romania, earthquake

1997 ◽  
Vol 40 (2) ◽  
Author(s):  
M. Popeskov
Keyword(s):  
Geomagnetic Field ◽  
Large Scale ◽  
Regional Scale ◽  
Extensive Study ◽  
Field Variation ◽  
Regional Effect ◽  
Data Set ◽  
Small Magnitude ◽  
Observatory Data ◽  
Set Up

There has recently been much discussion of large-scale interactions of fault zones and the influence of large-scale processes in the preparation and triggering of earthquakes. As a consequence, an official recommendation was issued to set up observational networks at regional scale. In this context, the existing network of standard geomagnetic observatories might play a more important role in future tectonomagnetic studies. The data from standard geomagnetic observatories are basically not appropriate for the detection of small-magnitude and, in most cases, spatially very localized geomagnetic field changes. However, their advantage is a continuity in a long-time period which enables the study of regional tectonomagnetic features and long-term precursory changes. As the first step of a more extensive study aimed at examining the features of observatory data for this purpose, a three-year data set from five European observatories has been analyzed. Some common statistical procedures have been applied along with a simple difference technique and multivariate linear regression to define local geomagnetic field changes. The distribution of M ³ 4.5 earthquakes in Europe, in a corresponding period, was also taken into account. No pronounced field variation, related in time to the M 5.7 Timisoara (Romania) earthquake on July 12, 1991, was found at Grocka observatory at about 80 km from the earthquake epicenter. However, an offset in level of the differences in declination which include Grocka observatory, not seen in the case of differences between other observatories, could be associated with a possible regional effect of the M 4.8 earthquake which occurred in September 1991 at about 70 km SE from Grocka.

scholarly journals Looking Beyond the Household: The Importance of School Factors in Understanding Elementary Grade Retention in Rural Khyber Pakhtunkhwa, Pakistan

2017 ◽  
Vol 46 (1) ◽  
Author(s):  
Bushra Rahim
Keyword(s):  
Student Performance ◽  
Grade Retention ◽  
Retention Rate ◽  
Retention Rates ◽  
School Level ◽  
School Factors ◽  
Data Set ◽  
Continuous Increase ◽  
Khyber Pakhtunkhwa ◽  
The Impact

This paper contributes to the limited literature on the educational outcomes of children in rural Khyber Pakhtunkhwa (KP), Pakistan. It explores the impact of school-level factors such as physical resources, teachers and school characteristics on retention to the last grade of primary in the KP province for the time period 2007-12. Two sources of data were used to measure the retention rates. One of which is an official compilation of institutional data on education known as Education Management Information System (EMIS). The second data source, Annual Status of Education Reports (ASER), is a household data set with a rich set of household covariates, teachers’ characteristics and student performance data on reading and mathematics. The results from regression analyses indicate that children are more likely to complete primary education cycle when they receive instructions in local language and when the pupil-teacher ratio is below a certain threshold. Results also reveal that a continuous increase in school size beyond a certain threshold (> 400 enrollment) is related to a decrease in retention rate. Further, mixed schools (all-boys’ schools having girls enrolled in them) were found to have better retention rates than boys’ schools.

scholarly journals MODIS observed increase in duration and spatial extent of sediment plumes in Greenland fjords

2014 ◽  
Vol 8 (4) ◽  
pp. 1161-1176 ◽  
Author(s):  
B. Hudson ◽  
I. Overeem ◽  
D. McGrath ◽  
J. P. M. Syvitski ◽  
A. Mikkelsen ◽  
...  
Keyword(s):  
North Atlantic Ocean ◽  
Regional Scale ◽  
Greenland Ice Sheet ◽  
Sediment Concentration ◽  
Retrieval Algorithm ◽  
Freshwater Flux ◽  
River Plumes ◽  
Data Set ◽  
In Situ Data ◽  
The North

Abstract. The freshwater flux from the Greenland Ice Sheet (GrIS) to the North Atlantic Ocean carries extensive but poorly documented volumes of sediment. We develop a suspended sediment concentration (SSC) retrieval algorithm using a large Greenland specific in situ data set. This algorithm is applied to all cloud-free NASA Moderate Resolution Imaging Spectrometer (MODIS) Terra images from 2000 to 2012 to monitor SSC dynamics at six river plumes in three fjords in southwest Greenland. Melt-season mean plume SSC increased at all but one site, although these trends were primarily not statistically significant. Zones of sediment concentration > 50 mg L−1 expanded in three river plumes, with potential consequences for biological productivity. The high SSC cores of sediment plumes ( > 250 mg L−1 expanded in one-third of study locations. At a regional scale, higher volumes of runoff were associated with higher melt-season mean plume SSC values, but this relationship did not hold for individual rivers. High spatial variability between proximal plumes highlights the complex processes operating in Greenland's glacio–fluvial–fjord systems.

scholarly journals Occurrence of intersex in wild freshwater fish in Slovenian rivers: a histological evaluation

2016 ◽  
Vol 67 (3) ◽  
pp. 216-222
Author(s):  
Milka Vrecl ◽  
Vlasta Jenčič
Keyword(s):  
Freshwater Fish ◽  
Salmo Trutta ◽  
Testicular Tissue ◽  
Histological Evaluation ◽  
Thymallus Thymallus ◽  
Barbus Barbus ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
Rivers And Streams ◽  
Brown Trout Salmo Trutta ◽  
Insight Into

Abstract The aim of this preliminary research was to establish if there are intersex occurrences in wild freshwater fish in Slovenian rivers and streams. In the first study we evaluated all fish species of both sexes obtained from the river Ljubljanica from its source to mouth. In the second study we focused on the rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta m. fario) males from 30 rivers and streams in different parts of Slovenia. The male gonads were histologically assessed for the presence of oocytes to determine the frequency and degree of intersex. Oocytes were found in the testicular tissue of a single grayling (Thymallus thymallus) and in the adipose tissue adjacent to the testis of a single common barbel (Barbus barbus), both from the Ljubljanica. Several cyst-like structures that resemble degenerated presumptive oocytes were also present in several trout testes. This preliminary report is the first of its kind in Slovenia. To gain a better insight into the intersex issue in Slovenia, we plan to regularly biomonitor freshwater pollution by histologically examining fish gonads and, if possible, by determining vitellogenin plasma levels in fish.

scholarly journals Anisotropic Kirchhoff pre-stack depth migration at the COSC-1 borehole, central Sweden

2019 ◽  
Vol 219 (1) ◽  
pp. 66-79 ◽  
Author(s):  
H Simon ◽  
S Buske ◽  
P Hedin ◽  
C Juhlin ◽  
F Krauß ◽  
...  
Keyword(s):  
Regional Scale ◽  
Seismic Profile ◽  
Black Shales ◽  
Data Sets ◽  
Data Set ◽  
Depth Migration ◽  
Scandinavian Caledonides ◽  
Long Offset ◽  
Nappe Complex ◽  
Seve Nappe Complex

SUMMARYA remarkably well preserved representation of a deeply eroded Palaeozoic orogen is found in the Scandinavian Caledonides, formed by the collision of the two palaeocontinents Baltica and Laurentia. Today, after 400 Ma of erosion along with uplift and extension during the opening of the North Atlantic Ocean, the geological structures in central western Sweden comprise far transported allochthonous units, the underlying Precambrian crystalline basement, and a shallow west-dipping décollement that separates the two and is associated with a thin layer of Cambrian black shales. These structures, in particular the Seve Nappes (upper part of the Middle Allochthons), the Lower Allochthons and the highly reflective basement are the target of the two approximately 2.5 km deep fully cored scientific boreholes in central Sweden that are part of the project COSC (Collisional Orogeny in the Scandinavian Caledonides). Thus, a continuous 5 km tectonostratigraphic profile through the Caledonian nappes into Baltica’s basement will be recovered. The first borehole, COSC-1, was successfully drilled in 2014 and revealed a thick section of the seismically highly reflective Lower Seve Nappe. The Seve Nappe Complex, mainly consisting of felsic gneisses and mafic amphibolites, appears to be highly anisotropic. To allow for extrapolation of findings from core analysis and downhole logging to the structures around the borehole, several surface and borehole seismic experiments were conducted. Here, we use three long offset surface seismic profiles that are centred on the borehole COSC-1 to image the structures in the vicinity of the borehole and below it. We applied Kirchhoff pre-stack depth migration, taking into account the seismic anisotropy in the Seve Nappe Complex. We calculated Green’s functions using an anisotropic eikonal solver for a VTI (transversely isotropic with vertical axis of symmetry) velocity model, which was previously derived by the analysis of VSP (Vertical Seismic Profile) and surface seismic data. We show, that the anisotropic results are superior to the corresponding isotropic depth migration. The reflections appear significantly more continuous and better focused. The depth imaging of the long offset profiles provides a link between a high-resolution 3-D data set and the regional scale 2-D COSC Seismic Profile and complements these data sets, especially in the deeper parts below the borehole. However, many of the reflective structures can be observed in the different data sets. Most of the dominant reflections imaged originate below the bottom of the borehole and are situated within the Precambrian basement or at the transition zones between Middle and Lower Allochthons and the basement. The origin of the deeper reflections remains enigmatic, possibly representing dolerite intrusions or deformation zones of Caledonian or pre-Caledonian age.

scholarly journals A meta-analysis and statistical modelling of nitrates in groundwater at the African scale

2016 ◽  
Vol 20 (6) ◽  
pp. 2353-2381 ◽  
Author(s):  
Issoufou Ouedraogo ◽  
Marnik Vanclooster
Keyword(s):  
Statistical Model ◽  
Nitrate Concentration ◽  
Regional Scale ◽  
Shallow Groundwater ◽  
Statistical Modelling ◽  
Nitrate Pollution ◽  
Nitrate Contamination ◽  
Data Set ◽  
Nitrate Concentrations ◽  
Groundwater Systems

Abstract. Contamination of groundwater with nitrate poses a major health risk to millions of people around Africa. Assessing the space–time distribution of this contamination, as well as understanding the factors that explain this contamination, is important for managing sustainable drinking water at the regional scale. This study aims to assess the variables that contribute to nitrate pollution in groundwater at the African scale by statistical modelling. We compiled a literature database of nitrate concentration in groundwater (around 250 studies) and combined it with digital maps of physical attributes such as soil, geology, climate, hydrogeology, and anthropogenic data for statistical model development. The maximum, medium, and minimum observed nitrate concentrations were analysed. In total, 13 explanatory variables were screened to explain observed nitrate pollution in groundwater. For the mean nitrate concentration, four variables are retained in the statistical explanatory model: (1) depth to groundwater (shallow groundwater, typically < 50 m); (2) recharge rate; (3) aquifer type; and (4) population density. The first three variables represent intrinsic vulnerability of groundwater systems to pollution, while the latter variable is a proxy for anthropogenic pollution pressure. The model explains 65 % of the variation of mean nitrate contamination in groundwater at the African scale. Using the same proxy information, we could develop a statistical model for the maximum nitrate concentrations that explains 42 % of the nitrate variation. For the maximum concentrations, other environmental attributes such as soil type, slope, rainfall, climate class, and region type improve the prediction of maximum nitrate concentrations at the African scale. As to minimal nitrate concentrations, in the absence of normal distribution assumptions of the data set, we do not develop a statistical model for these data. The data-based statistical model presented here represents an important step towards developing tools that will allow us to accurately predict nitrate distribution at the African scale and thus may support groundwater monitoring and water management that aims to protect groundwater systems. Yet they should be further refined and validated when more detailed and harmonized data become available and/or combined with more conceptual descriptions of the fate of nutrients in the hydrosystem.

Sign in / Sign up

Export Citation Format

Share Document