A method for the enumeration of myxomycetes in soils and its application to a wide range of soils

Abstract A standardised most-probable-number technique for estimating the number of myxomycete plasmodium-forming units (PFUs) in soils has been developed and tested experimentally. Application of the method to a local soil showed that the uppermost layers contained the most PFUs. Its application to 44 surface soils from various parts of the world detected myxomycetes in 36, of which 4 were desert soils. In general, highest numbers of PFUs (up to 9000·g⁻¹ soil) were recorded in grassland and agricultural soils. The nature of the PFUs has not been definitely resolved but they are probably myxamoebae, myxoflagellates and microcysts.     

Seasonal population changes of myxomycetes and associated organisms in four woodland soils

Abstract The number of myxomycete plasmodium-forming units (PFUs) and associated microorganisms in soils from four woodland sites in the West of England were estimated at approximately monthly intervals over the course of a year, and other characteristics of the soils were determined. The numbers of PFUs were low except in an unusual high-phosphate woodland soil. This soil contained the fewest dictyostelid slime moulds. Conversely, the woodland soil with most dictyostelids contained the fewest PFUs. Naked soil amoebae were the most abundant phagotrophs. Myxomycetes were a comparatively small component of the phagotrophic community of the three typical woodland soils. Changes in the populations of naked amoebae, ciliates, myxomycetes and dictyostelids were sometimes synchronized with changes in the bacterial populations, which showed 9–35-fold seasonal variations in abundance at the four sites.     

Secondary metabolites of slime molds (myxomycetes)

The compounds reported from the slime molds (myxomycetes) species are described. Almost 100 natural compounds including their chemical structures and biological activities are described in this review article. Only metabolites with a well-defined structure are included.     

Biological components of Sites of Special Scientific Interest in Wales

The designation of Sites of Special Scientific Interest (SSSIs) is one of the major statutory measures for wildlife protection in Britain. In this account, procedures for selecting SSSIs are outlined, and the representation of habitats and species in different taxonomic groups which qualify 731 SSSIs notified in Wales (in November 1994) are summarized. Biological SSSIs occupy approximately 9.6% of the total area of Wales. There are significant differences in the numbers and sizes of sites characteristic in the uplands (few large), lowlands (many small) and coast (intermediate). Over 70% of the biological SSSIs have more than one qualifying feature. Most sites (663, 90%) have been selected for one or more habitats, and many sites (328, 45%) have particular species attributes. In relation to their total extent in Wales, some habitats (including ombrotrophic peatland, dwarf-shrub heathland, rich fen and sand dune) have greater proportional representation in SSSIs than others (such as upland grassland, woodland and scrub). These differences reflect conservation priorities for Welsh habitats which are related to the wider British context. As expected, birds and vascular plants contribute to notification of a greater number of sites than other groups; invertebrates, lichens and bryophytes qualify in some sites and require further evaluation in others; except for bats, mammals are comparatively poorly represented as special features. Birds qualify many of the largest SSSIs in Wales (breeding assemblages in the uplands and overwintering wildfowl and waders in estuaries). Possibilities for future refinement of the SSSI series are considered. It is suggested that the establishment of conservation sites is sufficiently advanced in Britain to permit worthwhile examination of the composition and function of the network as a whole against conservation objectives.     

Seasonal population changes of myxomycetes and associated organisms in five non-woodland soils, and correlations between their numbers and soil characteristics

Abstract Microbial populations and other characteristics of five non-woodland soils from sites in the West of England were studied quantitatively over the course of a year, and special attention was paid to the changing abundance of myxomycetes. The latter, expressed as numbers of plasmodium-forming units (PFUs), were on average more abundant than in three representative woodland soils. During the year, instances were recorded in which rapidly increasing populations of bacteria were accompanied by increasing numbers of phagotrophic microorganisms, including myxomycetes, and others in which rapidly increasingly populations of phagotrophs were accompanied by falls in the numbers of bacteria. Oscillating predator-prey relationships were suggested. Myxomycetes were generally a significant component of the phagotrophic populations, even exceeding 50% of the total soil naked amoebae. Data on the biological and abiotic characteristics of woodland [3] and non-woodland soils were combined and statistically analysed for correlations. Myxomycete abundance was positively correlated with numbers of soil amoebae, ciliates, total bacteria, myxobacteria and nematodes, but inversely correlated with numbers of dictyostelid cellular slime moulds. It was positively correlated with soil pH and level of potassium, and negatively correlated with moisture content, organic matter content, and nitrogen/phosphorus ratio. Calculations suggest that the biomass of myxomycetes in temperate soils is commonly 6.4–64 mg dry weight · m⁻².     

Characterisation of the European Marine Sites in South West England: The Fal and Helford Candidate Special Area of Conservation (cSAC)

The Conservation (Natural Habitats, & c.) Regulations 1994 which implement the Habitats Directive (Council Directive 92/43/EEC) and Birds Directive (79/409/EEC) in the UK include a number of provisions for the protection of European Marine Sites (marine candidate Special Areas of Conservation (cSAC) and Special Protection Areas (SPAs)), including the requirement for competent authorities to assess the effects of new and existing consents, permissions and authorisations to ensure that they are not having an adverse effect on the integrity of the site (Regulations 48 and 50). In England and Wales site characterisation, a process which involves the collation, integration and critical evaluation of existing site knowledge, is seen by the Environment Agency (EA) and the nature conservation bodies (English Nature – EN, and the Countryside Council for Wales – CCW) as an important step towards evaluating the effects of consented discharges and activities on the interest features of EMS, and is fundamental to the development of ecosystem-based management. An on-going project, led by the Marine Biological Association of the United Kingdom (part of the Plymouth Marine Science Partnership) in collaboration with EA, EN and CCW, sets out to characterise the impacts and risks associated with water and sediment quality in relation to the integrity and interest features of selected European Marine Sites in southwest England and Wales. Using published information and unpublished data-sets from regulatory agencies, conservation bodies, and research institutes, evidence is compiled on the links between potentially harmful activities, environmental quality and resultant biological effects, and includes an evaluation of long-term change. An overview of results is presented here for one of the UK marine sites studied, The Fal and Helford candidate SAC, highlighting the threats to biota from point-source and diffuse pollutants, together with major gaps in our understanding. Some of the priorities for new research and better integrated monitoring to address nature conservation objectives (to maintain and restore the system) are discussed.     

Slimes in the city: The diversity of myxomycetes from inner-city and semi-urban parks in Sydney,Australia

Natural and agricultural areas are rapidly becoming urbanised, causing changes in habitat structure and diversity. Although the effect of urbanisation on the diversity of terrestrial plants and animals has been well studied, there is a significant gap in our understanding of how urbanisation impacts diversity in protists. Here, we measure the diversity of plasmodial slime moulds (a group of large, macroscopic protists also known as myxomycetes) in inner-city and semi-urban parks. We studied the impact of a range of environmental characteristics (pH, temperature, canopy cover, area of green space and substrate type) on species richness and composition of myxomycetes. We also examined the influence of different degrees of urban development surrounding these parks. Species composition was significantly different between substrate types but not between inner-city and semi-urban parks. Temperature was the only environmental characteristic that affected diversity, having a negative effect on myxomycete presence. Our findings suggest that myxomycete diversity in urban parks is driven by factors at the substrate level, and not by the park's location within the city (inner city or semi-urban).     

Seasonal abundance during the summer months of some cattle-visiting Muscidae (Diptera) in northeast England

Abstract. 1. Regular samples of flies swarming around cattle in Northumberland, England, were collected from late May to early October 1980–82, during weather judged to be suitable for fly activity.
2. Results were grouped into weekly periods and averaged to reduce variation caused by the weather.
3. For all species of Muscidae that were caught in reasonable numbers, the changes in abundance through the season are described.
4. The proportion of each species in the total sample is discussed; biting species were not sampled as efficiently as were non-biting species. Hydrotaea trritans and Morellia simplex were the most numerous species forming 49% and 32% of the catch respectively.
5. The total numbers of flies were low at the beginning of the sampling period, rose to a maximum in mid-July, stayed high until mid-September and then declined by October.     

Distribution and abundance of three species of Sitona (Coleoptera: Curculionidae) in grassland in England

The distribution and abundance of weevils of the genus Sitona was assessed at 16 sites in England. The sites were chosen to cover a wide range of geographical and agricultural regions. Adult weevils were sampled on four occasions, from May to August 1993. Numbers of adults, larvae and pupae were determined for each site on four occasions from June to September 1994. Numbers of larvae declined throughout the year in which they were sampled and pupae were most numerous in July. The population density of adults increased through the sampling period in both years. Sites close to pulse crops had the largest population levels of weevils, with Sitona lineatus L. the dominant species. No differences in the population levels of Sitona hispidulus (F.) or S. flauescens (Marsh.) were detected. Evidently populations of the latter two species are fairly constant in grassland and most of the variation in the population densities of these three species found in English grassland can be attributed to the migratory behaviour of S. lineatus and the proximity of pulse crops.     

The distribution and abundance of species of Danthonia DC on the New England Tablelands (Australia)

The distribution and percent frequency of the 13 species and one variety of Danthonia recorded on the New England Tablelands were examined in a survey of 110 predominantly pastoral sites. The relationships between site factors and the presence and percent frequency of the different Danthonia species were subjected to canonical correlation analysis. Individual species were found to have particular sets of environmental factors associated with their distribution and percent frequency; a fact not well recognized in the past. The most common factor associated with the abundance of Danthonia was either a long time since the last cultivation or no cultivation at all. Other factors such as altitude, drainage, soil parent material, soil texture and total soil phosphorus status were also of some importance. The six species most commonly recorded throughout the New England Tablelands were D. racemosa RBr, D. pilosa RBr, D. laevis J. Vickery, D. linkii Kunth., D. richardsonii Cashmore and D. tenuior (Steud.) Conert. Of these the first three are ecologically wide species. The first two can coexist with other naturalized species under grazing while D. laevis tends to disappear with disturbance. D. linkii and D. richardsonii require fairly narrow habitat conditions but these conditions and consequently these species are common. Both species respond positively to disturbance. Danthonia linkii increases with cultivation and D. richardsonii colonizes eroded soil surfaces. Danthonia tenuior has more restricted requirements and is not so frequent The other seven species and one variety did not occur often enough for detailed study and the occurrence of two of these species, D. carphoides and D. caespitosa must be considered as rare.     

麦积山肉鞭毛虫的物种多样性

用活体观察法对迄今缺乏了解的麦积山肉鞭类原生动物的物种多样性进行了调查,共鉴定出水生肉鞭虫100种,包括2个未知种。鞭毛亚门（Mastigophora）有2纲9目15科31属59种。植鞭纲（Phytomastigophorea）有52种,其中眼虫目(Euglenida) 36种,占鞭毛虫物种总数的61.02%,为优势类群;动鞭纲（Zoomastigophorea）仅有7种,没有明显的优势类群。肉足亚门（Sarcodina）有4纲6目19科32属41种。叶足纲（Lobosea）有31种,其中变形目（Amoebida）16种,占肉足虫物种总数的39.02%,为优势类群;表壳目（Arcellinida）12种,占29.27%,为次优势类群。在麦积山风景名胜区的南坡（为嘉陵江水系）分布有71种,北坡（为渭河水系）分布有56种,分水岭分布有13种,水生肉鞭毛虫的群落组成也显著不同;与国内典型的长江水系、雅鲁藏布江水系和黄河水系相比,麦积山分布的水生肉鞭毛虫群落组成均存在显著性差异。结果表明,麦积山水生肉鞭毛虫物种十分丰富,特有和稀有物种繁多,具有鲜明的独特性。     

Seasonal abundance of the stable fly Stomoxys calcitrans in southwest England

The stable fly Stomoxys calcitrans (L.) is a cosmopolitan biting fly of both economic and welfare concern, primarily as a result of its painful bite, which can cause blood loss, discomfort and loss of productivity in livestock. Between June and November in 2016 and May and December in 2017, Alsynite sticky‐traps were deployed at four Donkey Sanctuary sites in southwest England, which experience recurrent seasonal biting fly problems. The aim was to evaluate the seasonal dynamics of the stable fly populations and the risk factors associated with abundance. In total, 19 835 S. calcitrans were trapped during the study period. In both years, abundance increased gradually over summer months, peaking in late August/September. There were no relationships between seasonally detrended abundance and any climatic factors. Fly abundance was significantly different between sites and population size was consistent between years at three of the four sites. The median chronological age, as determined by pteridine analysis of flies caught live when blood‐feeding, was 4.67 days (interquartile range 3.8–6.2 days) in males and 6.79 days (interquartile range 4.8–10.4 days) in females; there was no significant, consistent change in age or age structure over time, suggesting that adult flies emerge continuously over the summer, rather than in discrete age‐related cohorts. The data suggest that flies are more abundant in the vicinity of active animal facilities, although the strong behavioural association between flies and their hosts means that they are less likely to be caught on traps where host availability is high. The implications of these results for fly management are discussed.     

Background levels of polycyclic aromatic hydrocarbons (PAH) and selected metals in new England urban soils

Polycyclic aromatic hydrocarbons (PAH) are byproducts of combustion and are ubiquitous in the urban environment They are also present in industrial chemical wastes, such as coal tar, petroleum refinery sludges, waste oils and fuels, and wood‐treating residues. Thus, PAHs are chemicals of concern at many waste sites. Risk assessment methods will yield risk‐based cleanup levels for PAHs that range from 0.1 to 0.7 mg/kg. Given their universal presence in the urban environment, it is important to compare risk‐based cleanup levels with typical urban background levels before utilizing unrealistically low cleanup targets. However, little data exist on PAH levels in urban, nonindustrial soils. In this study, 60 samples of surficial soils from urban locations in three New England cities were analyzed for PAH compounds. In addition, all samples were analyzed for total petroleum hydrocarbons (TPH) and seven metals. The upper 95% confidence interval on the mean was 3 mg/kg for benzo(a)pyrene toxic equivalents, 12 mg/kg for total potentially carcinogenic PAH, and 25 mg/kg for total PAH. The upper 95% confidence interval was 373 mg/kg for TPH, which exceeds the target level of 100 mg/kg used by many state regulatory agencies. Metal concentrations were similar to published background levels for all metals except lead. The upper 95% confidence interval for lead was 737 mg/kg in Boston, 463 mg/kg in Providence, and 378 mg/kg in Springfield.     

The reproductive productivity of the wild rabbit (Oryctolagus cuniculus) in southern England on sites with different soils

Rabbit numbers are rising in most parts of Britain. Previous research in southern England has indicated that the rate of increase in spring due to breeding may vary according to soil type. This has serious implications for the likely rate of invasion into new habitats and for planning control operations. To investigate the hypothesis, post-mortem examinations of over 2500 rabbits from 14 sites on sand, chalk or clay were made. The length of the breeding season and percentage of females breeding differed significantly between soil types but litter size and intra-uterine mortality did not. The product of breeding season length and litter size results in an estimate of annual productivity per adult female. This was 22, 20, and 14 young born per female on clay, chalk, and sandy sites, respectively. Rabbits may invade new habitats, such as set-aside, at different rates according to soil type and therefore require different levels of control regime for population management.     

Distribution,prevalence and mean numbers of larvalAnisakis simplex (Nematoda: Ascaridoidea) in Atlantic salmon,Salmo salar L. and their use as biological indicators of host stocks

Synopsis An estimate of the arithmetic mean number of larvalAnisakis simplex per salmon,Salmo salar, in the north Atlantic was obtained from data collected off west Greenland where salmon from both sides of the Atlantic intermingle. An average of 5.34 larvae was found in the body cavity or associated viscera of 771 age 1 salmon representing some 60.8% of the total number of larvae present. LarvalA. simplex were found at all sampling stations throughout the north Atlantic. In most samples prevalence varied only slightly from area to area.The mean numbers of larvae in the body cavity and on associated organs of salmon in samples from North America were significantly different between samples. Comparisons of the mean numbers of larvae with several known variables in the data were, therefore, considered: host's sex, host's sea-age, geographic locality, year and season of capture.There was evidence that the mean number of larvae per host was greater in salmon from Europe than in those from North America, but the data could not be used to providereliable estimates of the mean numbers of larvae from each area because of heterogeneity within areas. Thus the data from west Greenland and from continental home waters could net be used in calculations to determine the percentage composition of North American and European salmon in the Greenland fishery although they supported earlier findings of mixing of salmon stocks off west Greenland.The use of parasitological data in the identification of different Atlantic salmon stocks is discussed.     

Preliminary studies on the composition and rheological properties of the extracellular polysaccharide synthesized by pseudomonas PB1 (NCIB 11264)

A microorganism isolated from a carbohydrate-rich industrial effluent synthesized an exocellular slime polysaccharide composed of glucose and galactose in a molar ratio of 7.45 ± 0.68: 1, and two non-carbohydrate substituents acetate (3–4%) and pyruvate (5–9%). Contamination by rhamnose and mannose was detectable in crude polysaccharide samples. Solutions of the polysaccharide were pseudoplastic, but not thixotropic, and formed gels in the presence of certain trivalent cations.