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  • 1
    Electronic Resource
    Electronic Resource
    A new sampler for stream benthos, epiphytic macrofauna and aquatic macrophytes (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 11 (1981), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. A new sampler is described combining the advantages of both box and Surber samplers. The sample area is 200 × 250 mm (0.05 m2) and the device has been used to sample the benthos of rivers to a depth of c. 60 mm where the substratum consists of particles with diameters of 50 mm or less. The basic design may be used in water up to 0.5 m in depth, but with an optional top unit this depth may be increased to 1 m. Aquatic macrophytes can also be sampled either on their own or together with the underlying substratum. Results from sampling programmes designed to estimate macrophyte biomass, the biomass of the macroinvertebrate community and the density of Gammarus pulex are given as examples of the flexibility of the sampler on a variety of biotopes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1981.tb01243.x
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  • 2
    Electronic Resource
    Electronic Resource
    Comparison of three mapping procedures developed for river macrophytes (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 11 (1981), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. Three methods of mapping macrophytes on short sections of river are described and compared. All methods involve setting up a 1-m grid system over the site using permanent stakes to locate a series of temporary strings. The first method (detailed mapping), which generates a map, uses the grid system to locate accurately the position of macrophytes and substrata on the river bed. It is very time consuming and objectivity in mapping is difficult to achieve. The second method (points method) involves recording the macrophytes and substratum below each intersection of the 1-m grid system covering the study site. This method is fast, capable of giving estimates of percentage cover for the different substrata and macrophytes but does not produce a map. The third method (rectangles method) is regarded as both the most efficient and also the most objective of the three mapping procedures. The substratum or macrophyte dominating each 50 × 100 cm rectangle of river bed is recorded together with additional substrata and macrophytes present. The procedure is rapid to use in the field, provides a simplified map of the study site and is more amenable to detailed analysis than the two previous methods. All three mapping methods are best suited to rivers less than 20 m wide where safe wading and good visibility can be guaranteed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1981.tb01268.x
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  • 3
    Electronic Resource
    Electronic Resource
    Growth and recession of aquatic macrophytes on an unshaded section of the River Lambourn, England, from 1971 to 1976 (1981)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 11 (1981), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. The growth and recession of the macrophytes on an unshaded section of the R. Lambourn was documented by a mapping procedure from March 1971 to December 1976. The seasonal patterns were determined mainly by the dominant macrophytes. Ranunculus penicillatus var. calcareus and Ranunculus peltatus. Ranunculus grew rapidly in spring and early summer, mainly colonizing areas of gravel and reached a summer maximum. The greatest loss of plants was in August and September but losses continued through the winter to give minimum cover in March. Berula and Callitriche did not show regular seasonal growth patterns but their growth was largely confined to times when there was little growth of Ranunculus. Increase in area of Ranunculus in the spring was positively correlated with the mean discharge at that time. The growth of Ranunculus appeared to be restricted when shading was caused by turbid water due to dredging or by accumulation of epiphytic algae on the surface of the plants in years when discharge was low. Discharge also influenced the substrata underlying Ranunculus and the area of silt under Ranunculus beds was negatively correlated with discharge. The factors thought to influence growth of Ranunculus were used to develop a conceptual model of growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1981.tb01269.x
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  • 4
    Electronic Resource
    Electronic Resource
    Seasonal changes in biom ass of macrophytes on shaded and unshaded sections of the River Lambourn, England (1982)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 12 (1982), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. Monthly changes in the biomass of Ranunculus, Berula and Callitriche were recorded on two 50-m sites on the River Lambourn at Bagnor between March 1971 and October 1973. On the unshaded site. Ranunculus was the dominant macrophyte and characteristically its biomass changed from 20–40 g dry wt m-2 in March to around 400 g dry wt m-2 at the end of the growing season. On the shaded site, where Berula was the dominant macrophyte. the biomass of Ranunculus was lower than on the unshaded site. There was no significant difference between the mean biomasses of Berula on these two sites but Callitriche had a signifieantly higher biomass on the shaded site. Estimates of the total biomass of macrophyte on each site were calculated and the biomass of macrophyte removed during cutting operations each summer was also assessed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1982.tb00621.x
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  • 5
    Electronic Resource
    Electronic Resource
    Growth and recession of aquatic macrophytes on a shaded section of the River Lambourn, England, from 1971 to 1980 (1982)
    Oxford, UK : Blackwell Publishing Ltd
    Freshwater biology 12 (1982), S. 0 
    Details
    ISSN: 1365-2427
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: SUMMARY. The growth and recession of macrophytes on a shaded section of the R. Lambourn were documented by a mapping procedure. With the exception of Ranunculus spp., the changes in total cover did not indicate directly the pattern of growth and recession of the macrophyles. Analysis of gross changes, expressed as gains and losses on cover, indicated that colonization of gravel and silt by the dominant macrophyte, Berula erecta, did not vary seasonally. Colonization was at a constant rate of about 8% of the site each month throughout the year and this accounted for 50% of the total number of gains by Berula. Gains of Berula from Ranunculus showed an annual cycle with a maximum during the summer when Ranunculus was in recession. Gains of Berula from Callitriche spp. also varied annually but the maximum was during the autumn. Total losses of Berula were at a constant rate throughout the year but were to gravel and silt during the winter, to Ranunculus in spring and early summer and to Callitriche in late summer and autumn. Analysis of loss of Berula with time indicated that the position of the Berula carpet was constantly changing. The growth and recession of Berula could not be linked in a meaningful way to environmental variables. Callitriche and Ranunculus both showed an annual pattern of growth and recession. There was temporal separation of the two macrophytes with Ranunculus growing mainly in spring and early summer and Callitriche showing maximum growth in late summer and autumn, and some evidence of spatial separation. The observed differences between years in the growth of Callitriche could not be attributed to any of the environmental variables measured.Discharge was thought to be an important variable controlling the growth of Ranunculus since increase of Ranunculus in the spring was positively correlated with the mean discharge at that time. In years when discharge was low, the growth of Rununculus appeared to be restricted by shading from epiphytic algae which accumulated on the plant surfaces under these conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2427.1982.tb00600.x
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  • 6
    Electronic Resource
    Electronic Resource
    Life-cycle of Planorbarius corneas (L.) (1963)
    [s.l.] : Nature Publishing Group
    Nature 198 (1963), S. 805-806 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The following observations were made on a population in a pond about 1 mile west of Burghfield, near Reading, Berkshire. The snails are present in large numbers on the submerged aquatic vegetation at the edge of the pond and four samples were collected with a pond net during the summer of 1962, at ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/198805a0
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  • 7
    Electronic Resource
    Electronic Resource
    The prediction of water temperatures in chalk streams from air temperatures (1991)
    Springer
    Hydrobiologia 210 (1991), S. 183-189 
    Details
    ISSN: 1573-5117
    Keywords: water temperature ; rivers ; regression ; climate change
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The water temperatures of four English chalk streams which have a large groundwater component in their discharge were studied. Simple linear regression models were used to described mean monthly water temperature as a function of mean monthly air temperature. There were no significant between-year differences within rivers, in the case of the Lambourn, Winterbourne and Tadnoll. For the Frome, only one year out of the eight studied was significantly different from the others. Further analysis revealed that there were no significant differences between the Tadnoll, Winterbourne and Lambourn, and that the relationship between maximum monthly water temperature and air temperature was best described by the equation y = 4.29 + 0.55x. Using this pooled equation to predict river temperatures for the three rivers studied gave mean deviations of less than 1 °C from the observed temperatures. It was concluded that linear regressions of the type presented are sufficiently accurate to predict the thermal regimes of rivers for a variety of limnological purposes. They can also be used to predict the temperature response of chalk streams to increased air temperatures that may be produced by climate change. The results predict that chalk streams would show less increase in temperature than other running waters under these circumstances.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00034676
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  • 8
    Electronic Resource
    Electronic Resource
    The chalk-stream environment (1992)
    Springer
    Hydrobiologia 248 (1992), S. 3-9 
    Details
    ISSN: 1573-5117
    Keywords: chalk stream ; chalk hydrology ; stream flow ; water temperature ; water chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Chalk is a very pure and porous form of limestone. Water percolates down through the rock to form aquifers which overflow as springs forming chalk streams which receive little surface runoff. Passage through the rock is relatively slow and smooths out irregularities in rainfall and stabilises the water temperature. As a result the streams tend to have a regular annual hydrograph with a relatively small difference between winter and summer flows and with no spate conditions; and the temperature range in the streams remains closer to the annual mean than in rivers receiving more surface runoff. The water is calcareous with a pH of 7.4–8.0 and an ample supply of plant nutrients. The streams support diverse and productive communities of plants and animals and the restricted temperature range is particularly suitable for the growth of brown trout.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008881
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  • 9
    Electronic Resource
    Electronic Resource
    River Laboratory of the Freshwater Biological Association Twenty-five years of research (1992)
    Springer
    Hydrobiologia 248 (1992), S. 1-2 
    Details
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00008880
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