摘要:

AbstractThe ability to use large databases to classify estuaries on the basis of any number of characteristics may be valuable in planning a national system of estuarine reserves in Australia which will conserve the range of variability within and between regions.A recently completed inventory of Australian estuaries and marine embayments has provided quantitative data on a large number of estuaries from which comparisons are made with existing classifications based on qualitative descriptions.Area measurements are analysed for mangroves, salt marsh/clay pan, seagrass, intertidal flats and open water from 571 tropical and subtropical estuaries north from Carnarvon on the west coast around to Coffs Harbour on the east.The relative proportions of mangroves and salt marsh within estuaries show strong relationships with average annual rainfall although there are no consistent trends in the absolute area of each wetland type.The estuaries are classified into three distinct groups on the basis of rainfall and the dominant wetland type.Greater tide range coincides with a greater area per estuary of all wetland types. As with rainfall, the estuaries fall into three categories of wetland proportions.

ISSN:1052-7613    

DOI:10.1002/aqc.3270040102

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe distribution of seabirds west of Scotland was studied relative to water masses in August 1988. Surface salinity was used to indicate the ship's position relative to the water masses described in the literature. Comparisons were made between seabird densities in Inshore Water, the Northern Coastal Current, the Southern Coastal Current and Atlantic/Hebridean Water.Seabird density varied with water mass; some species distributions suggested strong habitat associations. Water masses represent marine habitats, with different physical regimes supporting different marine life; patterns in bird distribution are likely to reflect prey distribution and availability.Manx shearwatersPuffinus puffinus, razorbillsAlca torda, guillemotsUria aalge, and kittiwakesRissa tridactylawere found mostly in Inshore Water, with lower densities in the Northern and Southern Coastal Current water. Only trace numbers of these species occurred in Atlantic/Hebridean Water.Storm petrelsHydrobates pelagicus, fulmarsFulmarus glacialisand puffinsFratercula arcticawere found in very low densities in Inshore Water, and were dispersed in higher densities throughout the more oceanic areas.These data suggest that in late summer the Inshore Water of southwestern Scotland has the highest densities of seabirds potentially vulnerable in the event of an oil incident.

ISSN:1052-7613    

DOI:10.1002/aqc.3270040103

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis study collated information relating to acidification of running and standing waters on Sites of Special Scientific Interest (SSSIs) throughout Britain in acid‐sensitive areas.Of those SSSIs which occur in acid‐sensitive areas of Britain, 196 have water bodies. The following information was obtained for each site if available: details of local geology and soils, types of land use and management, water quality data and data relating to biological components of both the aquatic and riparian habitats.In addition, samples from 112 water bodies were collected for water chemistry and epilithic diatom analysis. Results from each site were placed into existing critical loads and species response models to determine whether acidification had occurred.Results showed that the fresh waters on 141 SSSIs had probably suffered acidification. This was most acute in north Wales, with mid Wales, south‐west and north‐east Scotland and northern England also being badly affected.A wide variety of changes in the biological status of water bodies relating to acidification were found to have been recorded on SSSIs, ranging from phytoplankton, invertebrate and macrophyte community changes to decline of fish, amphibian, bird and mammal populations.Catchment afforestation may be a problem in poorly buffered areas and has probably contributed to freshwater acidification on 40 SSSIs.Comparison with critical loads maps for acidity in UK fresh waters reveals that existing commitments on acidifying emissions (the EC Large Combustion Plant Directive) will not be sufficient to prevent further acidification on a number of SSSIs. In order to achieve a protection of the nature conservation interest of fresh waters further commitments to emission reductions will be ne

ISSN:1052-7613    

DOI:10.1002/aqc.3270040104

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper reports on the application of a chemical fractionation scheme for assessing the amounts, forms and potential mobility (recycling potential) of phosphorus in the sediments of the freshwater Loch Leven, which is currently highly topical in relation to eutrophication and its manifest dense, potentially toxic, blue‐green algae. The findings are placed in the context of the biological importance of the loch, the problems it is experiencing and some management options for its restoration.The fractionation scheme adopted enabled quantification of phosphorus in sediment pore water and in sedimentary solid phases classified as ‘loosely‐bound’, ‘reductant‐soluble’, ‘oxide‐adsorbed’, ‘organic’, ‘apatite‐bound’ and ‘residual’ in the sections of a 16‐cm core collected in January 1990.Vertical profiles of reductant‐soluble and pore water phosphorus and iron show redox‐controlled remobilization and cycling within the sediment to be the principal mechanisms leading to the surface sediment enrichment of phosphorus observed during the winter months.The association of phosphorus with iron oxyhydroxides in the reductant‐soluble fraction, which accounts for 31% of the total phosphorus (2470 mg kg−1) in the 0–1 cm section compared with 0.5% loosely‐bound, 25.6% oxide‐adsorbed, 27.9% organic, 9.9% apatite‐bound and 5.1% residual, restricts the release of phosphorus to the overlying water column in winter.Extrapolation of the data to the whole loch suggests that in early 1990 more than 40 tonnes of phosphorus were associated with the surfaces of iron oxyhydroxides in the upper 10 cm of Loch Leven sediment, about five times that required to raise loch water concentrations to maxima of 0.15 mg L−1observed during the algal blooms of summer under conditions favourable to the release of phosphorus from the sediments.Despite recent measures to reduce external inputs of phosphorus and thereby limit the degree of eutrophication of Loch Leven, there appears to have been little overall change in the inventory of phosphorus associated with iron in the upper 10 cm of sediment since 1970.There should be more detailed seasonal and spatial studies of the chemical fractionation and mobility of phosphorus in Loch Leven sediments to investigate the extent to which release from the reductant‐soluble iron oxyhydroxide fraction (internal loading) contributes to the highly elevate

ISSN:1052-7613    

DOI:10.1002/aqc.3270040105

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe types of pressures evident in coastal regions are typified by the Jervis Bay region in south‐eastern Australia which, despite a long history of human occupation, remains largely undisturbed. How much longer those values and the ecological processes which sustain them will remain viable is questionable.This paper describes the development of a conservation management strategy which sought an integrated approach to management of the terrestrial and marine resources of the Bay region. A geographical information system (GIS) was developed for the region, using the raster‐based E‐RMS GIS software system.A continuum of conservation management options for the region was defined, ranging from no change to the presently limited protected area system (which covers only 7.5% of the region), to almost complete reservation. The preferred option, known as the Jervis Bay Conservation Zone, was derived using a landscape ecology approach. This involves a coordinated approach to conservation management by private and public agencies and individuals, with variable levels of control on the use of core habitat and adjacent land/sea areas.Three specific findings of relevance to the management of coastal aquatic resources elsewhere were that (1) traditional ‘reservation‐based’ approaches to conservation management in isolation are not likely to be effective in conserving biodiversity over time; (2) the planning process should be open for review by non‐technical audiences to facilitate community understanding and support; and (3) GIS can be a very useful tool for data organization

ISSN:1052-7613    

DOI:10.1002/aqc.3270040106

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThe River Blythe lies between the cities of Birmingham and Coventry. It has been notified recently as a statutory Site of Special Scientific Interest (SSSI) and is one of the few whole‐river SSSIs in Britain.It possesses a combination of natural course and structure which is a rare feature of lowland rivers in England. There is a clear succession of plant communities from its source to its confluence with the River Tame. Botanically it is one of the richest rivers in England.A study in 1982 recorded 159 macroinvertebrate taxa from the river. A notable feature is the species richness of the molluscs, oligochaetes and caddis‐flies.The Blythe is subject to a range of pressures including land drainage, recreation and development (buildings and infrastrucure). The appropriate option for its conservation management is limitation of catchment development.In order that this nationally important resource is conserved for future generations, a strategic approach to catchment management is needed combined with urban and infrastructure developments which are environmentally sustainable.The preparation of a catchment management strategy needs to be given a priority. The success of such a strategy will be dependent on cooperation between English Nature, the National Rivers Authority, the local planning authorities and the many riparian owners and occupiers.English Nature is cooperating with the National Rivers Authority to produce a ‘special ecosystem’ classification so that statutory Water Quality Objectives can be set to protect river SSSIs like the Blythe.8. The goodwill of the riparian owners and occupiers is needed for the protection and enhancement of wildlife habitats along th

ISSN:1052-7613    

DOI:10.1002/aqc.3270040107

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270040108

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270040109

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270040110

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY

ISSN:1052-7613    

DOI:10.1002/aqc.3270040111

出版商:John Wiley&Sons, Ltd    

年代:1994

数据来源: WILEY