The Anglesey lakes,Wales, UK—A palaeolimnological study of the eutrophication and nature conservation status

1. Palaeolimnological techniques were used to investigate recent environmental change in three shallow, coastal lakes (Coron, Dinam and Penrhyn) within biological SSSIs on Anglesey, Wales, U.K., where agriculture has influenced two sites while a third received sewage effluent. 2. The Penrhyn core was dated radiometrically and the timescale of the other two sites estimated by correlation. A range of palaeopigment, geochemical, diatom and chironomid analyses were made on the samples. 3. Results suggest that eutrophication has increased at all three sites in the last 50 years. Palaeopigment analyses indicate that Coron has had abundant blue–green algal populations, the Dinam sediments were highly organic and Penrhyn has been the most eutrophic. Trace metal profiles suggested significant sediment mixing. Although concentrations were sometimes low, diatom profiles from the sites include marked recent increases in Stephanodiscus, Cyclostephanos and Thalassiosira spp. 4. While there was a period of rapid eutrophication in Coron in the late-1960s, there are recent signs of reduced nutrient loading. Penrhyn appears the most enriched (and eutrophic from earlier time) and Dinam the least. Chironomid analyses suggest Coron has been the most enriched and two alternative explanations are put forward for the Chironomus loss in the recent sediments. Dinam has changed little, remaining mesotrophic and retaining the eutrophication-intolerant Pseudochironomus. In Penrhyn there has been a slow but progressive development of eutrophication, becoming mildly eutrophic at an early stage, with the loss of Pseudochironomus. 5. Environmental histories derived from sediment data of the three lakes have been related to specific catchment events and the significance of the relationship with lake ecosystem stability is discussed. The study shows the contribution of palaeolimnology to freshwater conservation.     

The Anglesey lakes,Wales, UK — Changes in trophic status of three standing waters as inferred from diatom transfer functions and their implications for conservation

1. A diatom-phosphorus (P) transfer function was applied to fossil diatom assemblages in sediment cores from three Anglesey lakes of conservation importance, in order to reconstruct quantitatively the recent history of total P (TP) concentrations for each lake. The results indicate that all three lakes have been eutrophic throughout the period represented by the cores. 2. The model suggests that Llyn Coron and Llyn Dinam experienced gradual increases in TP concentration (core base to 20 cm), followed by marked, rapid increases from the time represented by a sediment depth of 20 cm (early 1970s for Llyn Coron), most probably associated with agricultural intensification. 3. A recent decline in TP concentration at Llyn Coron and Llyn Dinam, associated with reductions in external P loading, is indicated by the model, although current levels are still considerably higher than those estimated for the base of the cores (Dinam: current=112 μg L⁻¹; base=65 μg L⁻¹, and Coron: current=156 μg L⁻¹; base=70 μg L⁻¹). 4. No clear changes in diatom-inferred TP concentration were observed for Llyn Penrhyn over the 70 year period represented by the core. However, the reconstruction for this lake is inaccurate because: (a) the sediment record appears to be disturbed, and (b) unlike Llyn Coron and Llyn Dinam, diatom preservation and modern analogues are poor, and the present TP concentration (>1 mg L⁻¹) is beyond the TP range of the model. 5. Continued control of the external TP loads from agricultural sources is essential to prevent further increases in lake TP concentrations at Llyn Coron and Llyn Dinam. Given the problems with the Llyn Penrhyn data, it is not possible to draw any firm conclusions regarding future site management. However, the impact of the recent installation of a phosphate stripping plant at the local sewage works should be monitored, to identify whether a reduction in external P loading results in a decrease in epilimnetic TP concentrations, and in turn whether this causes changes to the biological community structure of the lake.     

The ecology and conservation of Llyn Idwal and Llyn Cwellyn (Snowdonia National Park,North Wales,UK)—two lakes proposed as special areas of conservation in Europe

1. This paper gives a comprehensive account of the ecology of Llyn Idwal and Llyn Cwellyn, two nationally well known and internationally important conservation lakes in Snowdonia National Park, North Wales. Idwal has a small but precipitous catchment with relatively large areas of heathland and base rich bare rock. Cwellyn has a larger catchment with a substantial proportion of woodland, including coniferous plantations, and a long history of human activity. 2. The chemistry of the waters in both lakes is indicative of nutrient-poor conditions but Idwal exhibits relatively high alkalinity and pH values. 3. The diatom floras are typical of nutrient-poor upland waters, with species composition reflecting the alkalinity differences. Isoetids form a dominant component of the macrophyte floras, with the most diverse assemblage recorded at Idwal. 4. The zooplankton communities are distinctive, with only a small number of species occurring in both lakes. The macroinvertebrate faunas are dominated by insect taxa typical of stony shores. Supplementary stocking of the Idwal trout population has been reported. 5. The conservation importance of the sites lies primarily in their representation of nutrient-poor mountain lake systems and the macrophyte assemblages which include a number of rare species. In addition, a genetically unique arctic charr population is present in Cwellyn. 6. Impoundment, water abstraction, acidification, eutrophication and the recreational use of the sites are identified as potential environmental impacts. The conservation management of the sites is related to the extent of the reserve boundaries and catchment activities. Aspects of the future management and environmental monitoring of Idwal and Cwellyn as Special Areas of Conservation under the European Community Council Directive on the conservation of natural habitats and of wild fauna and flora are discussed. © 1998 John Wiley & Sons, Ltd.     

The identification,characterization and conservation value of isoetid lakes in Ireland

• 1. Soft‐water, oligotrophic isoetid lakes are vulnerable to eutrophication, acidification and alkalinization. As a result of these pressures a large proportion have undergone substantial deterioration in several European countries. The understanding of these systems has been limited by either a lack of lakes close to natural conditions or through receiving less focus in broader scale macrophyte surveys. This has resulted in a dearth of information on specific lake types in their natural condition. Sixty‐eight soft‐water lakes in Ireland were studied in order to achieve a better understanding of the biological and environmental conditions defining such lakes.
• 2. Eight groups of lakes were identified using cluster analysis and indicator species analysis. Three groups were representative of isoetid‐rich lakes displaying a high frequency of occurrence of Isoetes lacustris, Lobelia dortmanna or Eriocaulon aquaticum together with the almost ubiquitous Littorella uniflora. Canonical variates analysis indicated that alkalinity, total phosphorus (TP), catchment area, altitude, moors and heathlands, mean transect depth, colour and lake area were significant variables discriminating among the eight groups. Soft‐water lakes with high amounts of isoetids tended to be less exposed, have broad shallow littoral zones with a high transparency and be situated in smaller catchments. Total phosphorus and alkalinity were typically low, although one group of isoetid‐rich lakes had higher mean TP and alkalinity values. This group may contain lakes under threat from nutrient enrichment and alkalinization and also lakes that have higher TP and alkalinity naturally.
• 3. Lakes with a prevalence of isoetids supported a greater diversity of macrophytes and chironomids indicating that such lakes may represent suitable conservation targets as they act as surrogates for soft‐water lakes of high biodiversity. Other factors favouring a focus on isoetids in conservation strategies are their importance as a functional component in soft‐water lakes and their sensitivity to lake and catchment environmental change.

Copyright © 2008 John Wiley & Sons, Ltd.     

The historical and cultural importance of ponds and small lakes in Wales,UK

1. Ponds, as sources of water, are of fundamental importance to man. However what is now regarded as a pond may have been a natural water source exploited by man at different times to meet different needs, or may have been created for a multitude of different purposes—e.g. domestic or agricultural use, for transport, defence, ritual or industrial use, social aggrandizement or the creation of the picturesque. 2. Existing natural or older man-made ponds may hold peat deposits, of great importance for palaeo-environmentalists, or may have preserved archaeological features or artefacts or environmental data which would have perished in a dry environment. 3. Modern ponds, created in suitable locations for water retention, for conservation or recreational purposes, may well be found to overlie ancient water sources. Damage may inadvertently be done to ancient structures or environmental deposits if the scheme does not take archaeological considerations into account at the planning stage. 4. The historical and cultural importance of ponds and their archaeological potential is emphasized. The vulnerability of ponds is discussed, and recommendations made for improved liaison between archaeologists and ecologists. © 1997 John Wiley & Sons, Ltd.     

The application of palaeolimnology to evidence‐based lake management and conservation: examples from UK lakes

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The invertebrate community of the Peak–Speedwell cave system,Derbyshire, England — pressures and considerations for conservation management

1. The freshwater ecology of cave ecosystems has been poorly studied when compared with surface (epigean) systems. Most subterranean communities are typified by low abundance and low diversity of fauna due to the absence of primary production and other readily available organic carbon sources. 2. The macroinvertebrate community within the inter‐connected Peak–Speedwell cave system in the English Peak District was examined over a 2‐year period. The communities found in the surface streams which supply recharge to the Speedwell Cavern stream, and the communities in the three springs which discharge water from the cave system, were also examined. 3. Changes in the community were strongly associated with seasonal variations and natural hydrological variability. Spatial patterns within the caves reflect differences in water sources (sinking streams or percolation water) and in the ability of the organisms to survive and move through subterranean environments. 4. The majority of taxa recorded within the caves were also found at the surface either in the sinking streams or in the springs. 5. Threats to cave geo‐ecosystems, including quarrying, agriculture, waste disposal, groundwater abstraction and tourism/recreation, are examined and discussed in relation to the management and conservation of subterranean environments. Copyright © 2000 John Wiley & Sons, Ltd.     

Frameworks for marine conservation — non‐hierarchical approaches and distinctive habitats

• 1. Conservation efforts have traditionally been directed to ‘flagship’ species (whales, seals, migratory birds, etc.) that capture public attention. Often these flagship species occupy distinctive habitats. Distinctive habitats appear to be distinguished because of anomalous physical structures and unique oceanographic processes occurring within them, whereas representative habitats are not notable in this way. Distinctive habitats are found in areas of various physical anomalies described primarily by temperature, chlorophyll and topography.
• 2. Several different kinds of distinctive habitats can be defined by their anomalous physical structures and oceanographic and biological processes. Species diversity may be either higher or lower in distinctive than in representative habitats. Distinctive habitats predominantly belong to a class of environments called ‘ergoclines’, and are typically associated with elevated resources at some ‘trophic level’.
• 3. These elevated resources may be either the product of true production (i.e. they are generated (in situ), or they are the product of physical accumulation due to circulation mechanisms. These processes lie at the heart of the ecology of distinctive habitats, and are fundamental to maintenance of ecosystem health, ecological integrity, distributions, abundances and recruitment of species, patterns of animal migrations, and potential or actual fisheries yields.
• 4. Conservation strategies need to examine the relationships between distinctive and representative habitats and species diversity. A strategy, leading from studies on flagship or other focal species, could have several advantages. It should rejuvenate the inherent appeal and significance of ‘species’ approaches to marine conservation, provide a rationale for human interest and a new foundation for examination of marine ecological interactions. It would also require a novel synthesis of relationships between ‘species’ and ‘spaces’ approaches to marine conservation by asking how we can take the best advantage of both approaches, rather than seeing them as in conflict.

Copyright © 2002 John Wiley & Sons, Ltd.     

Ascidian communities in Southern Belize—a problem in diversity and conservation

• 1 Ecotourism has begun to impact the coral barrier reef of Belize. Pelican Cays, near the southern end of the reef, is one of the least disturbed areas and is rich in ascidian species.
• 2 Both the lack of stress and spatial competition probably contribute to the ability of normally cryptic species to live in exposed conditions. Activities associated with the growth in ecotourism are a potential threat to these unusual communities.
• 3 It is recommended that a rationale for the protection and management of this environmentally important area be developed.

     

Gastropod egg mass deposition on a temperate,wave‐exposed coastline in New South Wales,Australia: implications for intertidal conservation

• 1. The identification and protection of known breeding grounds is a high priority for the conservation of marine biodiversity. Here, we examine the intertidal habitats used by marine gastropods for the deposition of benthic egg masses along a wave‐exposed coastline in New South Wales, Australia.
• 2. A total of 200 surveys were conducted on 13 intertidal reefs. The egg masses of 46 species were identified, with a further eight distinct types recorded but remaining unidentified. Over half of the gastropods were found to deposit egg masses exclusively on the underside of boulders. Other intertidal substrata used for gastropod egg mass deposition included vertical and horizontal exposed rock surfaces, algal fronds and sand. Only eight species were found to attach their egg masses to more than one type of substratum.
• 3. Twelve reefs were classified into three categories according to exposure to wave action and habitat diversity. The mean number of species found depositing egg masses was compared using a standard eight surveys from each site. Sub‐maximally wave‐exposed reefs with maximal habitat diversity were found to support a significantly higher species richness of gastropod egg masses, compared with maximally wave‐exposed reefs with either maximal or sub‐maximal habitat diversity (p=0.000).
• 4. Gastropods that deposit egg masses on the underside of boulders were more likely to be found on sub‐maximally wave‐exposed reefs, whereas species that deposit egg masses in all other microhabitats were equally likely to be found breeding on sub‐maximally or maximally exposed reefs.
• 5. Gastropods with pelagic larvae tended to occur at a greater number of sites than those that hatch post‐metamorphosis. A significant difference was found between species grouped according to these two developmental modes for the mean number of sites at which egg masses were recorded (p=0.008).
• 6. Variation in the species richness of gastropods found depositing egg masses on different intertidal reefs appears to be influenced by the availability of suitable boulders and exposure to wave action. These factors should be taken into consideration during the selection of locations for intertidal protected areas.

Copyright © 2004 John Wiley & Sons, Ltd.     

The biology and conservation status of the grey nurse shark (Carcharias taurus Rafinesque 1810) in New South Wales,Australia

1. This paper summarizes aspects of the biology and conservation of the grey nurse shark (Carcharias taurus) in south-eastern Australian waters. This species has been a totally protected species in the State of New South Wales since 1984 and, as far as is known, was the first protected shark in the world. 2. Aspects discussed include systematics and taxonomy, distribution and biogeography, morphology and behaviour, reproduction and migrations, feeding habits, fisheries value and claims of attacks on humans, and impacts of protective beach meshing, spearfishing and SCUBA diving. The background to, and history of, moves to protect and conserve the species in New South Wales waters are also covered. 3. Results of surveys of the abundance of this species at Seal Rocks, an area off the mid-north coast of New South Wales where grey nurse sharks are known to aggregate, are reported. Also, a summary of the results of a telephone survey of commercial dive shop operators regarding the occurrence of grey nurse sharks along the New South Wales coastline is presented. 4. Finally, recommendations are made concerning the need for further research on, and management of, this species in Australian waters.     

The importance of spatial scales to analysis of fish diversity in Amazonian floodplain lakes and implications for conservation

The Amazon River Basin has the highest fish species diversity of any region in the world, but is under threat from anthropogenic perturbations including overharvesting, alien species and drought. We asked whether species diversity in this region is more a function of within‐lake species richness (i.e., α diversity) or differences among lakes (β diversity). Although many studies have reported on species richness and diversity in single habitats, the importance of measuring diversity at different spatial scales is not yet well established. We collected fish in 10 floodplain lakes along the Solimões River (Brazil), divided evenly between two lake types: those on islands in the river channel (island lakes) and those on the margins of the river (coastal lakes) during 2006. We partitioned fish diversity into three spatial scales: α = within each lake; β₁ = among lakes of the same type (coastal or island) and β₂ = between the two types of lakes, and compared their relative contributions to regional (γ) diversity. β₁ + β₂ contributed as much or more to γ diversity than did α. Although many of the 116 fish species were shared between lake types (S = 72), 32 species were found exclusively in coastal lakes and 12 species were found exclusively in island lakes. Coastal lakes, which were deeper and cooler than island lakes, consistently had higher fish species richness than island lakes. We suggest that it will be necessary to set areas large enough to contain multiple lakes of both types to preserve regional fish diversity.     

The determination of ecological status in shallow lakes — a tested system (ECOFRAME) for implementation of the European Water Framework Directive

• 1. The European Water Framework Directive requires the determination of ecological status in European fresh and saline waters. This is to be through the establishment of a typology of surface water bodies, the determination of reference (high status) conditions in each element (ecotype) of the typology and of lower grades of status (good, moderate, poor and bad) for each ecotype. It then requires classification of the status of the water bodies and their restoration to at least ‘good status’ in a specified period.
• 2. Though there are many methods for assessing water quality, none has the scope of that defined in the Directive. The provisions of the Directive require a wide range of variables to be measured and give only general guidance as to how systems of classification should be established. This raises issues of comparability across States and of the costs of making the determinations.
• 3. Using expert workshops and subsequent field testing, a practicable pan‐European typology and classification system has been developed for shallow lakes, which can easily be extended to all lakes. It is parsimonious in its choice of determinands, but based on current limnological understanding and therefore as cost‐effective as possible.
• 4. A core typology is described, which can be expanded easily in particular States to meet local conditions. The core includes 48 ecotypes across the entire European climate gradient and incorporates climate, lake area, geology of the catchment and conductivity.
• 5. The classification system is founded on a liberal interpretation of Annexes in the Directive and uses variables that are inexpensive to measure and ecologically relevant. The need for taxonomic expertise is minimized.
• 6. The scheme has been through eight iterations, two of which were tested in the field on tranches of 66 lakes. The final version, Version 8, is offered for operational testing and further refinement by statutory authorities.

Copyright © 2003 John Wiley & Sons, Ltd.     

Using systematic conservation planning to establish management priorities for freshwater salmon conservation,Matanuska‐Susitna Basin,AK, USA

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