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  • 1
    Electronic Resource
    Electronic Resource
    The selection of suitable indices for the measurement and analysis of fish condition (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 34 (1989), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: A survey of the studies published in two leading fisheries journals revealed that the analysis and measurement of condition, based on length-weight data, has been performed using a wide variety of indices and statistical procedures. Eight forms of index were identified which can be categorized into those which measure the condition of individual fish, i.e. condition factors‘, and those which measure the condition of subpopulations as a whole, i.e. regressions of log, 10 weight on log, 10 length and the parameters of such regressions. Analysis of a test data set indicated that both the form of index and properties of the data set size can dictate the patterns of condition observed. The various indices were reviewed in terms of appropriateness, simplicity and statistical correctness. It was concluded that an index should be selected only after a detailed examination of both the underlying assumptions of the index and the properties of the data set.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1989.tb03300.x
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  • 2
    Electronic Resource
    Electronic Resource
    Phenolic and carbohydrate signatures of organic matter in soils developed under grass and forest plantations following changes in land use (1997)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of soil science 48 (1997), S. 0 
    Details
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Comparisons were made between the phenolic and carbohydrate signatures of soil profiles developed under grass, spruce and ash stands. Samples were collected from a brown earth soil which was originally under the same land use, but over the past 43 years has supported different monocultures. Distinct signatures associated with each litter type were recorded in individual profiles. A relatively undecomposed phenolic fraction from lignin and hydrolysable carbohydrate fraction from plants had accumulated in the soils under spruce and ash. This largely reflected the quantity and quality of the litter inputs from the spruce and ash compared with the grass. The phenolic and hydrolysable carbohydrate fractions accounted for as much as 60% of the total organic carbon concentration in the deep horizons. In the grassland profile both fractions were more decomposed than under ash and spruce suggesting that the forest profiles had rapidly accumulated a carbon pool with a comparatively slow rate of decomposition. This was most apparent from the spruce profile (which contained 398 mg g−1 C carbohydrate hydrolysed using trifluoracetic acid (TFA) in the C horizon compared with 165 and 45 mg g−1 C under ash and grass respectively). We conclude that the decay rate of these fractions is a function of the vegetation type.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2389.1997.tb00551.x
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  • 3
    Electronic Resource
    Electronic Resource
    Transpiration efficiency of three Mediterranean annual pasture species and wheat (1998)
    Springer
    Oecologia 115 (1998), S. 32-38 
    Details
    ISSN: 1432-1939
    Keywords: Key words Annual pastures ; carbon isotope discrimination ; gas exchange ; transpiration efficiency water use efficiency
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Attempts to improve water use efficiency in regions with Mediterranean climates generally focus on increasing plant transpiration relative to evaporation from the soil and increasing transpiration efficiency. Our aim was to determine if transpiration efficiency differs among key species occurring in annual pastures in southern Australia. Two glasshouse experiments were conducted with three key pasture species, subterranean clover (Trifolium subterraneum L.), capeweed [Arctotheca calendula (L.) Levyns] and annual ryegrass (Lolium rigidum Gaudin), and wheat (Triticum aestivum L.). Transpiration efficiency was assessed at the levels of␣whole-plant biomass and water use (W), leaf gas exchange measurements of the ratio of CO2 assimilation to leaf conductance to water vapour (A/g), and carbon isotope discrimination (Δ) in leaf tissue. In addition, Δ was measured on shoots of the three pasture species growing together in the field. In the glasshouse studies, annual ryegrass had a consistently higher transpiration efficiency than subterranean clover or capeweed by all methods of measurement. Subterranean clover and capeweed had similar transpiration efficiencies by all three methods of measurement. Wheat had W values similar to ryegrass but A/g and Δ values similar to subterranean clover or capeweed. The high W of annual ryegrass seems to be related to a conservative leaf gas exchange behaviour, with lower assimilation and conductance but higher A/g than for the other species. In contrast to the glasshouse results, the three pasture species had similar Δ values when growing together in mixed-species swards in the field. Reasons for these differing responses between glasshouse and field-grown plants are discussed in terms of the implications for improving the transpiration efficiency of mixed-species annual pasture communities in the field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004420050488
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  • 4
    Electronic Resource
    Electronic Resource
    Acidifying processes and acid-base reactions in forest soils reciprocally transplanted along a European transect with increasing pollution (1998)
    Springer
    Biogeochemistry 41 (1998), S. 71-88 
    Details
    ISSN: 1573-515X
    Keywords: transplanted soils ; ion budgets ; soil solution chemistry ; mineralization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Forest ecosystems are currently beingexposed to changes in chemical inputs and it issuggested that physical climate is also changing. Anovel approach has been used to study the effects ofionic inputs and climatic conditions on forest soilsby reciprocally exchanging lysimeters containingundisturbed soil columns beween four forest sites inEurope. The soil columns contained no living roots andsimulated a clear cut situation. The soils chosenrepresented different stages of acidification and weretaken from sites along a transect of increasingexposure to acidic and nitrogen pollution. The purposeof the study was to quantify the reactions of soilswhen transferred to different environments. Elementbalances were used as an aggregated indicator todescribe the reaction of the soil. The input of protonsin local throughfall increased along the transect from0.01 kmol ha-1 y-1H+ at the unpolluted site up to 1.10 kmolha-1 y-1 at the most pollutedsite. Our results show that soil acidification always resultedfrom a combination of acid deposition and biologicaltransformations of nitrogen through nitrification ofimported ammonium, mineralized N, or stored N. Thebalances indicate that between 54% and 91%of the soil acidification resulted from nitrificationprocesses which were driven by a complex reaction whenclimatic and pollution conditions were changedsimultaneously. The combined changes in atmosphicinputs and climatic conditions, as expected withglobal change, may have serious consequences for soilacidfication and long term organic matter turnover.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005953302684
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of air pollutant-temperature interactions on mineral-N dynamics and cation leaching in reciplicate forest soil transplantation experiments (1997)
    Springer
    Biogeochemistry 39 (1997), S. 295-326 
    Details
    ISSN: 1573-515X
    Keywords: acidification ; aluminium ; Arrhenius’ law ; calcium ; cation leaching ; climate ; ion equilibrium ; forest soil ; N-cycle ; N-deposition ; nitrification ; temperature
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Increased emissions of nitrogen compounds have led to atmosphericdeposition to forest soils exceeding critical loads of N overlarge parts of Europe. To determine whether the chemistry offorest soils responds to changes in throughfall chemistry, intactsoil columns were reciprocally transplanted between sites, withdifferent physical conditions, across a gradient of N and Sdeposition in Europe. The transfer of a single soil to the various sites affected itsnet nitrification. This was not simply due to the nitrificationof different levels of N deposition but was explained bydifferences in physical climates which influenced mineralizationrates. Variation in the amount of net nitrification between soiltypes at a specific site were explained largely by soil pH. Within a site all soil types showed similar trends in netnitrification over time. Seasonal changes in net nitrificationcorresponds to oscillations in temperature but variable time lagshad to be introduced to explain the relationships. WithArrhenius‘ law it was possible to approximate gross nitrificationas a function of temperature. Gross nitrification equalled netnitrification after adaptation of the microbial community oftransplanted soils to the new conditions. Time lags, andunderestimates of gross nitrification in autumn, were assumed tobe the result of increased NH 4 + availability due either tochanges in the relative rates of gross and net N transformationsor to altered soil fauna-microbial interactions combined withimproved moisture conditions. Losses of NO 3 - were associated with Ca2+and Mg2+ in non-acidified soil types and with losses ofAl3+ in the acidified soils. For single soils the ionequilibrium equation of Gaines-Thomas provided a useful approximationof Al3+ concentrations in the soil solution as a functionof the concentration of Ca2+. The between site deviationsfrom this predicted equilibrium, which existed for single soils, couldbe explained by differences in throughfall chemistry which affectedthe total ionic strength of the soil solution. The approach of reciprocally transferring soil columnshighlighted the importance of throughfall chemistry, interactingwith the effect of changes in physical climate on forest soilacidification through internal proton production, in determiningsoil solution chemistry. A framework outlining the etiology offorest die-back induced by nitrogen saturation is proposed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005814929879
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  • 6
    Electronic Resource
    Electronic Resource
    The effects of ammonium sulphate deposition and root sinks on soil solution chemistry in coniferous forest soils (1997)
    Springer
    Biogeochemistry 38 (1997), S. 255-280 
    Details
    ISSN: 1573-515X
    Keywords: aluminium ; forest soils ; lysimeters ; nitrification ; nitrogen ; roots
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The effects of enhanced (NH4 2SO4deposition on soil solution cation and anion concentrations and annualionic fluxes were followed using a standardised experimental protocolin six European coniferous forests with contrasting soil types, pollutioninputs and climate. Native soil cores containing a ceramic suction cupwere installed in the field, roofed and watered every two weeks withlocal throughfall or local throughfall with added(NH4)2SO4 at 75 kgNH4 +-N ha-1 a-1. Livingroot systems were established in half of the lysimeters.Untreated throughfall NH4 +-N deposition at thesites ranged from 3.7 to 29 kg ha-1 a-1Soil leachates were collected at two weekly intervalsover 12 months and analysed for volume, andconcentrations of major anions and cations. Increasesin soil solution NO3 - concentrations inresponse to N additions were observed after 4–9months at three sites, whilst one sandy soil with highC:N ratio failed to nitrify under any of thetreatments. Changes in NO3 - concentrationsin soil solution controlled soil solution cationconcentrations in the five nitrifying soils, withAl3+ being the dominant cation in the more acidsoils with low base saturation. The acidification responses ofthe soils to the (NH4 2SO4additions were primarily related to the ability of thesoils to nitrify the added NH4 +. pH and soiltexture seemed important in controllingNH4 + leaching in response to the treatments,with two less acidic, clay/clay loam sites showingalmost total retention of added NH4 +, whilstnearly 75% of the added N was leached asNH4 + at the acid sandy soils. The presenceof living roots significantly reduced soil solutionNO3 - and associated cation concentrations attwo of the six sites. The very different responses of the sixsoils to increased (NH4)2SO4deposition emphasise that the establishment of N critical loadsfor forest soils need to allow for differences in N storagecapacity and nitrification potential.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005875505591
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  • 7
    Electronic Resource
    Electronic Resource
    Estimates of seasonal nitrogen fixation of annual subterranean clover-based pastures using the15N natural abundance technique (1995)
    Springer
    Plant and soil 175 (1995), S. 57-66 
    Details
    ISSN: 1573-5036
    Keywords: competition ; crop rotation ; farming systems ; ley farming ; soil nitrogen ; Trifolium subterraneum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Annual pasture legumes play a key role in ley farming systems of southern Australia, providing biologically fixed nitrogen (N) to drive the production of the pastures as well as subsequent crops grown in rotation. Seasonal inputs of biologically fixed N in shoot biomass of the subterranean clover (Trifolium subterraneum) component of grazed annual pastures were assessed using the15N natural abundance technique and appropriately timed sampling of herbage dry matter (DM) for N accumulation. At three study sites spanning a gradient across the Western Australian wheatbelt from 300 to 600 mm annual rainfall the performance of the clover and non-legume herbs and grasses was examined as paired comparisons involving two management treatments expected to give contrasting effects on pasture productivity, botanical composition and N2 fixation. The proportion of clover N derived from atmospheric N2 fixation (%Ndfa) ranged from 65 to 95% across sites, treatments and sampling times. Amounts of fixed N accumulated in clover shoot biomass ranged from 50 to 125 kg ha−1, and paralleled trends in clover production. Substantial increases in pasture production in high yielding treatments generally occurred without decrease in %Ndfa, suggesting that N2 fixation was essentially non-limiting to performance of the clover component. Seasonal profiles for accumulation of fixed N were skewed towards the late winter and spring period, particularly in low plant density pastures following a cereal crop. There were seasonal, site and treatment-specific effects on the proportion of clover and non-legume pasture components and consequently clover yield and N2 fixation were variably affected by competition from non-legume species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02413010
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  • 8
    Electronic Resource
    Electronic Resource
    The feeding relationships of brown trout, minnow and three-spined stickleback in an upland reservoir system (1990)
    Springer
    Hydrobiologia 208 (1990), S. 169-185 
    Details
    ISSN: 1573-5117
    Keywords: trout ; minnow ; stickleback ; reservoir ; diet
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stomach contents of 242 brown trout, 1440 minnow and 368 stickleback from the North Lake and of 121 trout, 1079 minnow and 332 stickleback from the South Lake of an upland reservoir system in Co. Wicklow (Ireland) were analysed. Macroinvertebrates from each reservoir were sampled in September 1982, June and September 1983, and June 1984. A further sampling in September 1984 involved only the South Lake as low water levels prevented littoral samples being taken in the North Lake. Vertical and horizontal hauls of zooplankton were also collected during September 1983 and 1984. The diets of the three species were compared on each date using Spearman Rank Correlation coefficients and Schoener's index of dietary overlap. The diets of the minnow and stickleback regularly showed significant correlation but the trout diet was very different except during periods of very reduced water levels when all species fed on zooplankton.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00007783
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of seed phosphorus concentration on the emergence and growth of subterranean clover (Trifolium subterraneum) (1993)
    Springer
    Plant and soil 155-156 (1993), S. 285-288 
    Details
    ISSN: 1573-5036
    Keywords: Trifolium subterraneum ; seed phosphorus ; emergence ; growth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Subterranean clover seed (Trifolium subterraneum cv. Dalkeith) with phosphorus concentrations of 0.75% (high P seed) and 0.48% (low P seed) and of uniform size (2.0–2.4 mm diameter) was used to measure the effect of seed P concentrations on seedling emergence and growth. Seedling emergence numbers were 35% greater for the high P seed, and this effect was independent of external P supply. High P seed also emerged more quickly than low P seed. Leaf emergence was faster and shoot dry weight was greater for seedlings grown from high compared with low P seed, but only when external P supply was deficient for plant growth. Phosphorus concentrations in the shoots of two-week old seedlings were 32–51% higher for high P seed, although by four weeks plants grown from high and low P seed had similar concentrations of P in their shoots. We suggest that establishing pastures using high P seed would improve both early and late season pasture production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00025038
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