The status and conservation of the freshwater pearl mussel Margaritifera margaritifera Linn. in Great Britain

All available records of the occurrence of the freshwater pearl mussel Margaritifera margaritifera Linn. in Great Britain have been collected. Analysis of these records shows that there has been a recent decline in numbers of the species, which is especially marked in England and Wales. The causes of this decline are thought to be primarily pollution and overfishing in England and Wales, and overfishing in Scotland. Apparently even sparse populations remain fertile, but it is concluded that unless conservation measures can reduce overfishing, pearl mussels will become rare and endangered. It is suggested that the best conservation measures will be to restrict pearl fishing to licensed fishermen, perhaps using non-destructive fishing methods, and to prohibit the use of sub-aqua equipment.     

The fish fauna of mountain streams in South Korean national parks and its significance to conservation of regional freshwater fish biodiversity

The fish fauna of mountain streams in the Jiri (440 km²) and Seorak (373 km²) National Park areas of South Korea was investigated from September 1998 to May 2001. A total of 5979 fish were collected and classified into 22 families and 60 species from both national parks. At Jiri, 30 species in 12 families of fishes were collected, while at Seorak there were 42 species in 17 families. Zacco temmincki [relative abundance (RA) 47.9%] was dominant at both parks. Subdominant species were Rhynchocypris kumkangensis (RA 10.8%), Zacco platypus (RA 9.4%), and Pungtungia herzi (RA 5.3%). A total of 20 species were found to be Korean endemic species, representing seven families. The relative abundance of Korean endemic species was higher at Seorak (30.5%) than Jiri (18.5%). One exotic species (Oncorhynchus mykiss) and two species translocated outside their native catchments (Hypomesus nipponensis and Coreoperca herzi) were collected. The proportion of Korean endemic freshwater fish species in both parks (33.3%) was higher than the overall proportion on the Korean peninsula (23.6%). Within the 14 South Korean mountain-area national parks as a whole, larger parks tend to have higher fish diversity. We conclude that South Korean national parks are important for conservation of the regional fish fauna, especially for endemic and endangered species. Current threats to conservation of fishes within South Korean national parks are identified and management solutions are suggested.     

The effect of reducing conditions on the solubility of phosphorus in a diverse range of European agricultural soils

The effects of reducing conditions on solubility of phosphorus (P) can directly influence water quality. The release of P is enhanced although the P is not directly involved in reduction processes. We here compare the responses to flooding of 12 overfertilized agricultural soils in widely varying pedological and management regimes, belonging to seven World Reference Base groups. The redox potential initially ranged from 305 to 515 mV and decreased to ?157 to ?195 mV within 32 days. The onset of reducing conditions led to an increase in the concentration of soluble P. The maximum rate of solubilization occurred within 1–3 weeks under reducing conditions, and the steady‐state concentrations of P never exceeded 200 μmol dm^?3. Four stages in the development of the reduction process are identified, and a simple empirical model describes the change in concentrations of soluble P. The potential of P release under reduction is positively correlated with the soil saturation with P. Flooding over a few weeks triggered the release of large amounts of P. Constant pe + pH is related to constant concentration of molybdate‐reactive P, suggesting that soluble P is effectively buffered so that P will be immobilized. In general the solubilization of P under reducing conditions is likely to be aggravated by the increased soil P status that has resulted from overfertilization of agricultural land with P. These findings bear on the establishment and long‐term effectiveness of riparian buffer zones where phosphorus is likely to accumulate by the interception of drainage.     

Long-Range Atmospheric Transport and Local Pollution Sources on PAH Concentrations in a South European Urban Area. Fulfilling of the European Directive

A 12 months study on urban atmospheric concentrations of polycyclic aromatic hydrocarbons (PAH) contained in the particulate matter with an aerodynamic diameter less than or equal to 10 microns (PM10) was carried out in Zaragoza (Spain) from July 12th, 2001 to July 26th, 2002 by using a high-volume air sampler able to collect the PAH supported on a Teflon-coated fibre glass filter. Samples were analysed by using Gas Chromatography Mass Spectrometry (GC-MS/MS). PAH of high molecular weight, indeno[1,2,3-cd]pyrene (IcdP), benzo[g,h,i]perylene (BghiP) and coronene (Co) were the most abundant compounds. The concentrations of benz[a]pyrene equivalent carcinogenic power (BaP-eq) showed a mean value of 0.7 ng/m³ with 22.5% of the samples exceeding the 1.0 ng/m³ guide value established by the European Directive. These episodes were mainly produced during cold season. Regarding meteorological variables, a positive effect of the prevalent wind “cierzo” (NW direction) over the Zaragoza city was confirmed from the environmental point of view. The NE, E and S directions, corresponding to highway and industrial areas were the directions showing the high PAH atmospheric concentrations. Despite the proximity of a high-level traffic highway, stationary sources related to industry were the dominant source of PAH in the sampled area. Vehicular emissions and natural gas home heating also contributed to PAH concentrations. The predominance of local pollution sources versus long-range transport on PAH concentrations was shown. However, the contribution of long-range transport of anthropogenic origin from other European areas was reflected for specific dates on PAH concentrations and PM10 levels.     

Retention of ingested 110mAg by a freshwater fish,Salmo trutta L.

Water, Air, &; Soil Pollution - The accumulation kinetics were followed on 19 fingerling trout fed 5 days a week, with 110mAg labelled rations. Nine trout, placed in individual compartments,...     

The status of the otter (Lutra lutra L.) in Norfolk

The county of Norfolk was surveyed for otters between December 1974 and June 1975 inclusive. Only 32 sites out of a total of 233 sites visited had signs of otters and a further 8 records were received. A total population of 17 pairs was estimated, considerably below the carrying capacity of the area.     

The status and conservation of the butterfly Plebejus argus L. (Lepidoptera: Lycaenidae) in North West Britain

A survey was made of the declining butterfly, Plebejus argus L., in North West Britain in 1983. Twenty-six colonies were found on limestone grassland, many of them large. Twenty colonies were found on heathland, but most were relatively small. One large colony that inhabits mossland was rediscovered. P. argus occupies early succesional habitat at low altitude, predominantly on sheltered southerly facing slopes. Through biotope loss and fragmentation and declining traditional management, suitable habitat is created only sporadically in modern Britain. Some of these habitats (especially on heathland) are short lived. Thus, many colonies are transient. As P. argus forms closed colonies and rarely flies far, the decline appears to be a compound effect of reduced amounts of suitable habitat and inability to colonise them: the distances are often too great. Active conservation is required to check the decline of P. argus, especially habitat management and also introduction to suitable habitat now beyond the dispersal range of P. argus. Recommendations are made.     

The habitat of Lythrum hyssopifolia L. in cambridgeshire,its only surviving English locality

Lythrum hyssopifolia, always a scarce species in the British Isles, is now confined to Cambridgeshire and to Jersey, Channel Islands. In Cambridgeshire it is restricted to an area of 10 km², where it occurs locally in shallow depressions in arable fields, consistently associated with Bryum klinggraeffii, Juncus bufonius, Plantago major ssp. intermedia and Polygonum persicaria. it is dependent on both winter flooding and the regular ploughing of these sites for its survival. The vegetation in which it is found is referable to the Isoeto-Nanojuncetea, largely composed of annual flowering plants and ephemeral bryophytes. Lythrum and its most frequent associates share: (1) the ability to germinate in spring; (2) the lack of long-term competitive ability; (3) a similar floral biology, being predominantly self-pollinated; and (4) potentially long-lived seeds. Two groups of bryophytes grow with Lythrum, monoecious species reproducing sexually and dioecious species reproducing vegetatively by rhizoid-tubers.     

The conservation of freshwater fishes in the British isles

This paper briefly reviews the status and distribution of populations of freshwater fishes in the British Isles and their worth as a resource. The total value of freshwater fishes to the community is far greater than is normally appreciated and includes, in addition to the economic sport and commercial fisheries, amenity, recreational, educational, and scientific, aspects as well as a potentially useful store of genetic material for the future. The main human pressures on existing fish stocks are discussed under the headings of fisheries, pollution, and land-used. The principal trends in the British Isles are away from natural and stable mixed fish populations towards artificially maintained, unstable stocks of a few species of sporting or commercial value. In particular the rarer, more sensitive, fish stocks with poor powers of distribution are being eradicated and replaced by commoner, more robust forms with greater powers of distribution. The rarer species and genetic strains can only survive if constructive conservation projects are initiated expeditiously at a variety of levels.     

Environmental change and its impact on the freshwater fishes of Iran

Factors affecting the distribution and abundance of freshwater fishes in Iran are described. These include climate, devegetation, irrigation, and natural water level fluctuations (termed pre-industrial) and such factors related to industrialisation and population increase as devegetation, water abstraction, fishing, pollution, and faunal introductions. Conservation schemes are outlined and commented on and a list of threatemed fishes is given.     

Soil Indicators of Paleoenvironmental Conditions in the South of the East European Plain in the Quaternary Time

Eurasian Soil Science - Climatic conditions are an important factor affecting mineralogical and chemical compositions of soils and paleosols with the formation of paleosol archives that reflect...     

生态系统健康研究现状及其定量化研究初探

阐述了健康的生态系统定义及其研究瓶颈与途径 ,健康的生态系统可以活力、组织性和恢复力等定性指标描述和衡量。中尺度生态系统定量化健康评价研究的主要瓶颈是确立健康生态系统标准。生态系统健康评价研究的途径可从生态系统受胁迫压力角度、系统恢复力或系统反作用力角度以及生态系统受到潜在“威胁”预测和健康预防的角度考虑 ,而系统结构和功能相结合是生态系统健康评价的基础     

The microbial biomass and its activity and structure in the soils of old forests in the European Russia

The humus-accumulative layer of soils (podzolic, gray, rzhavozem, burozem, and karbolitozem) of old-age forests (>60–450 years old) localized in various vegetation subzones (middle-taiga, southern taiga, subtaiga, dark coniferous forests outside the boreal region, and mountain forests) of the European part of Russia (22 sites of soil sampling of them, 13 in nature reserves and specially protected territories) was studied. The carbon content of the microbial biomass (C_mic) in the soil was determined by the substrate-induced respiration method. The fungal to bacterial ratio was determined by the selective inhibition technique with antibiotics. The basal respiration (BR) was also measured. The BR/C_mic = qCO₂ ratio and the portion of C_mic in the total organic soil carbon was determined. It was shown that the C_mic and BR in the soils of a separate vegetation subzone varied significantly; however, their values increased from the middle-taiga to dark coniferous subzone and decreased in the mountain-forest zone (348 ± 44, 670 ± 66, 1000 ± 86, 1142 ± 49, 789 ± 79 μkg C/g soil and from 0.68 ± 0.23, 1.85 ± 0.10, 2.13 ± 0.15, 1.56 ± 0.14, 0.92 ± 0.07 μkg CO₂-C/soil h, respectively). The fungal component in the humus-accumulative layer of soils is 53–99% of the total Cmic; however, its absolute values increase from the middle subzone to the southern one. The Cmic pool and the total BR in the profile of some soils (mineral horizons and forest litter) were calculated.     

Modeling the reintroduction of lynx to the southern portion of its range

We modeled populations of lynx (Lynx canadensis) and snowshoe hares (Lepus americanus) to determine prey densities required for persistence of lynx translocated to the southern portion of the species' range. The models suggested that a density of 1.1-1.8 hares/h is required for lynx persistence; these densities are higher than those reported for most hare populations across the USA. We found that lynx dispersal and density-independent mortality substantially increased the hare density required for lynx persistence. Reintroduction success was associated with number of release events, total number of animals released, and timing of release relative to the phase of the hare population cycle. However, no release protocol could override the negative effects of low prey density or high population losses. We conclude that successful lynx reintroduction requires high hare densities and minimal anthropogenic disturbance; few areas in the contiguous USA currently posses such qualities.     

Uptake from water,depuration and tissue distribution of110mAg in a freshwater fish,Cyprinus carpio L.

Radionuclide accumulation was studied on a group of 20 fish maintained at 20±1 °C in spring water containing 30 Bq mL^?1 of^110mAg. Because of a very significant radionuclide adsorption onto available surfaces and in order to simulate chronic exposure, the water was completely renewed three times a week. Accumulation of^110mAg was slow, with an estimated time to maximum contamination level of 180 days. The concentration factor, calculated from the ratio of the integrals of the curves representing the radionuclide concentration in filtered water and in whole fish reached a maximum value of 106 (w.w.). After 41 days exposure, 10 fish were placed in non-labelled water, renewed daily, to follow^110mAg depuration. A two-compartment exponential model was fitted to the depuration data. The corresponding radionuclide half-lives were relatively short, 0.8 (Tb₁) and 30 days (Tb₂), and after 6 weeks the fish retained about 30% of their initial^110mAg content. The liver and digestive tract retained most^110mAg. Although they only represented respectively about 4 and 10% of the total body mass, these two organs accounted for 30–40% of the total radionuclide body burden.