bluuebunny/crossref_metadata_2025 huggingface dataset:
Soil‐incorporated trifluralin protects cotton (Gossypium hirsutum) from root‐absorbed herbicides
Authors: KLEIFELD Y. , RUBIN B. , BLUMENFELD T. , HERZLINGER G. , BUXBAUM H. , GOLAN S.
Published: July 2006

Summary: Résumé: Zusammenfassung

Mechanical incorporation of a tank mixture of trifluralin in combination with fluometuron, diuron or prometryne in the soil to a depth of 10 cm protected emerging cotton from the damage caused by these herbicides in the absence of trifluralin. The incorporated tank mixtures, which were activated by sprinkler irrigation, controlled weeds which were tolerant to trifluralin alone. The different reaction of weeds and cotton to the soil‐incorporated herbicide mixtures corresponded to the reaction of their root systems to trifluralin. Weeds whose root system was shortened significantly by trifluralin were sensitive to the tank‐mixed, soil‐incorporated herbicides.

La trifluraline incorporée au sol protége le coton (Gossypium hirsutum) des herbicides à absorption racinaire

L'incorporation mécanique de mélanges de trifluraline avec du fluométuron, du diuron ou de la prométryne, à des profondeurs de sol 10 cm, protégeait le coton au moment de la levée contre les dommages occasionnés par ces herbicides en l'absence de trifluraline. Les mélanges incorporés, quiétaient activés par irrigation par aspersion, détruisaient les mauvaises herbes qui étaient tolérantes à la trifluraline seule. La réaction différente des mauvaises herbes et du coton aux mélanges d'herbicides incorporés correspondait à la réaction de leur système racinaire à la trifluraline. Les mauvaises herbes dont le systéme racinaire était raccourci par la trifluraline étaient sensibles aux mélanges d'herbicides incorporés.

Schutz der Baumwolle (Gossypium hirsutum) vor wurzelabsorbierten Herbiziden durch eingearbeitetes Trifluralin

Nach Einarbeitung von Tankmischungen von Trifluralin mit Fluometuron, Diuron oder Prometryn bis in 10 cm Bodentiefe blieben Baumwoll‐Keimpflanzen von den sonst von diesen 3 letzgenannten Herbiziden verursachten Schaden frei, Mittels der Tankmischungen ließen sich gegenuber Trifluralin allein unempfindliche Unkrauter bekampfen. Die unterschiedliche Reaktion der Unkrauter und der Baumwolle auf die eingearbeiteten Herbizidmischungen entsprachen der Reaktion ihrer Wurzeln auf Trifluralin. Soweit die Entwicklung von Unkrautwurzeln durch Trifluralin signifikant gehemmt wurde, waren diese Arten gegenuber den eingearbeitenen Tankmischungen empfindlich.
Competitive ability and threshold levels of three broadleaf weed species in sunflower
Authors: ONOFRI A. , TEI F.
Published: July 2006

Summary: Résumé: Zusammenfassung

Data collected from field trials carried out in different years and environments were used to determine competitive ability and threshold levels of Ammi majus L., Chenopodium album L. and Sinapis arvensis L. The hyperbolic model showed a good fit to the experimental data. The three broadleaf weeds showed low and similar competitive indices (i ranging from 1–08 to 1–75), supporting the hypothesis of a high sunflower competitive ability. The economic threshold was four to six plants m−2 for all three weeds in the case of weed control by hoeing and about six plants m−2 for S. arvensis in the case of a postemergence treatment with imazamethabenz. Limitations and approximations in estimating competitive parameters are pointed out and discussed.

Aptitude à la compétition et seuils de nuisibilité de trois mauvaises herbes dicotylédones dans le tournesol

Des données recueillies dans des expérimentations au champ conduites dans différents environnements et au cours de différentes années ont été utilisées pour déterminer l'aptitude à la compétition et les seuils de nuisibilité de Ammi majus L., Chenopodium album L. et Sinapis arvensis L.

Le modéle hyperbolique fournissait un bon ajustement aux données.

Les trois mauvaises herbes avaient des indices de compétition bas et similaires (i de 1,08 à 1,75) ce qui conforte l'hypothèse d'une forte aptitude à la compétition du tournesol.

Les seuils économiques étaient 4–6 plantes m−2 pour toutes les mauvaises herbes dans le cas de désherbage mécanique et environ 6 plantes m−2 pour S. arvensis dans le cas de traitement de post‐levée avec l'imazaméthabenz.

Les limitations et les approximations dans l'évaluation des paramètres de la compétition sont identifiés et discutés.

Konkurrenzkraft und Schadensschwellen von drei dikotylen Unkrautarten in Sonnenblume

Anhand von Ergebnissen aus Freilandversuchen in verschiedenen Jahren auf verschiedenen Standorten wurden die Konkurrenzkraft und die Schadensschwellen von Ammi majus L., Chenopodium album L., und Sinapis arvensis L, bestimmt. Die Ergebnisse ließen sich mit einer hyperbolischen Gleichung gut beschreiben. Die Konkurrenzindices i von 1,08 bis 1,75 waren fur alle 3 Arten ahnlich niedrig, worin sich die starke Konkurrenz der Sonnenblume widerspiegelt. Bei mechanischer Unkrautbekampfung lagen die Schadensschwellen fur alle 3 Unkrauter zwischen 4 und 6 Pflanzen m−2, fur Nachauflaufbehandlung mit Imazametabenz fur Sinapis arvenis bei 6 Pflanzen m−2. Grenzen und Annaherung der Bestimmung von Konkurrenzparametern werden eingehend diskutiert.
Interference between triazine‐resistant Brassica napus and Panicum miliaceum
Authors: MILLER T. W. , CALLIHAN R. H.
Published: July 2006

Atrazine carryover often limits growers to production of atrazine‐tolerant crops the year following application, and allows the increase of triazine‐tolerant weed species such as Panicum miliaceum L. (wild proso millet). Tiriazine‐resistant Brassica napus L. cv. ‘Triton’ (oilseed rape) was tested to characterize the nature of interspecific interference with P. miliaceum. In a greenhouse study, atrazine at 2.2 kg ha−1 depressed oilseed rape fruit (siliqua) number and fruit dry weight, and delayed flowering, but did not significantly affect height or weight of shoots, Oilseed rape fruit weight was reduced at 200 P. miliaceum plants m−2. fruit number and shoot weight were inhibited at 400 weeds m−2. and height was reduced and flowering delayed at 600 weeds m−2. Number and weight of fruits were reduced by one‐third after 8 weeks of interference as compared to oilseed rape grown with the weed for 4 weeks. Oilseed rape height was reduced by 29% and shoot weight by 55% by 600 weeds m−2 and 2–2 kg ha−1 atrazine, while fruit number and weight were reduced by 72%. Oilseed rape shoot weight was reduced by 74% by 600 weeds m−2 for 12 weeks of interference, while fruit number and weight were reduced by 85% and 82%. respectively.

In a field study, fluazifop reduced early season P. miliaceum cover by 72%, but did not increase oilseed rape cover. Mid‐season P. miliaceum shoot weight was decreased by 97% by fluazifop and oilseed rape shoot weight was increased by 34%. P. miliaceum control increased oilseed rape biomass by 38% at 89 days, but biomass of oilseed rape sown at 11.2 kg ha−1 with 2.2 kg atrazine ha−1 was not decreased by P. miliaceum interference at 89 days.
Volunteer barley interference in fibre flax (Linum usitatissimum L.)
Authors: MARSHALL G. , HACK CAROLINE M. , KIRKWOOD R. C.
Published: July 2006

Field experiments were conducted in 1989 and 1990 to determine the relationship between yield loss in fibre flax and the density of volunteer barley. At volunteer densities of 50–100 plants m−2, plants which emerged 7 days before those emerging synchronously with the flax produced a significantly greater reduction in stem height (1990), stem dry weight (DW) at flowering (1989 and 1990) and seed boll DW (1990). The relationships between flax stem and boll DW and volunteer density were described at two growth stages (flowering and maturity) using a linear model. The 1990 model indicated that where volunteer tiller densities ranged from 0 to 350 m−2, interference by 90 volunteer tillers m−2 (30 plants m−2) reduced stem DW by 2–9% at the flowering stage. These losses increased to 9–18% for stem DW plus 7–18% for seed boll DW when plants were grown to seed maturity. Due to the high value of flax fibres and seed it is concluded that an economic threshold based on the control of volunteer barley can be reached at low volunteer densities (30 plants m−2) especially if both fibre and oilseed were to be harvested.
Weed control in glyphosate‐tolerant sugarbeet (Beta vulgaris L.)
Authors: MADSEN K. H. , JENSEN J.E.
Published: July 2006

The effect of glyphosate on weeds was evaluated in greenhouse bioassays with five weed species and compared with a commercial mixture of phenmedipham and ethofumesate. Glyphosate was more active than a mixture of phenmedipham and ethofumesate on the weeds. Solanum nigrum was the most sensitive species to both herbicide treatments. The relative potency of glyphosate between the weeds showed consistency at 50% and 90% control levels for four out of five weed species, which could be ranked independently of control level because of similar response curves. In a field trial on sugarbeet genetically engineered to acquire glyphosate tolerance, a total of 720 g a.i. ha−1 of glyphosate applied in one, two or three applications gave similar or superior control of weeds to a total of 3.17 kg a.i. ha−1 mixture of metamitron, phenmedipham and ethofumesate applied in three repeated applications.
Resistance of dicot weeds to acetolactate synthase (ALS)‐inhibiting herbicides in Australia
Authors: BOUTSALIS P. , POWLES S. B.
Published: July 2006

A biotype of Sonchus oleraceus L. and two bio types of Sisymbrium orientate Torn., SSO 3 and NSO 1, are the first dicot weeds in Australia to develop resistance to ALS‐inhibiting herbicides. The resistant biotypes had been exposed to va rying periods of selection with sulfonylurea her bicides. All three biotypes are resistant to a range of sulfonylurea and imidazolinone herbicides. The S. orientale biotypes are also resistant to the triazolopyrimidine herbicide, flumetsulam. LD50 ratios of resistant Sonchus oleraceus for sulfony lurea and imidazolinone herbicides are greater than 64‐fold and 4.5‐fold, respectively. GR50 ratios are greater than 9 for sulfonylureas and 7.4 for imazapyr. The LD50 ratios for both S. orien tale biotypes for chlorsulfuron, sulfometuron methyl, metsulfuron‐methyl, flumetsulam and imazethapyr are greater than 110‐, 15‐, 7‐, 24‐ and 29‐fold, respectively. All resistant biotypes are susceptible to MCPA, diuron and diflufenican, herbicides which do not inhibit ALS.
Growth, development and nutrient accumulation in Senecio vulgaris L. and Chenopodium album L.
Authors: QASEM J. R. , HILL T. A.
Published: July 2006

Growth, development and nutrient accumula tion in Chenopodium album and Senecio vulgaris grown in pure and mixed stands were investi gated through several experiments conducted under glasshouse conditions. Results showed that the two weeds were different in their growth, development and tissue concentration and accu mulation of mineral elements. The mean concen trations of nitrogen, phosphorus, potassium, calcium and magnesium in shoots of C. album were higher than those of S. vulgaris, while root concentrations of nitrogen, potassium and mag nesium were lower for C. album. Marked dif ferences between the two weed species in their responses to different potassium levels were found. C. album had a high specific requirement for potassium while the reverse was true for S. vulgaris. The competitive ability and accumula tion of nutrients by C. album appeared to be greatly dependent on the availability of high potassium levels in the media.
Growth characteristics of spring barley and selected weeds. I. Effect of irradiance in growth chambers
Authors: SEMB K.
Published: July 2006

A study in growth chambers with three irradiance levels was carried out over a four‐week period on individual seedlings of spring barley (Hordeum vulgare L.) and five weed species (Brassica rapa L. ssp. oleifera (DC.) Metzger, Chenopodium album L., Galeopsis tetrahit L., Stellaria media (L.) Vill., and Viola arvensis Murray). Increased irradiance resulted in larger dry weight, net photosynthetic rate, relative growth rate (RGR), net assimilation rate (NAR), and lower leaf area ratio (LAR). The number of leaves per plant, plant length, leaf area, and shoot/root ratio were unaffected by irradiance levels, During the experimental period the net photosynthetic rate increased, while NAR remained the same, and RGR, LAR, and shoot/ root ratio decreased. On the basis of leaf area and dry weight, especially at the high irradiance level during the last part of the experimental period, barley, B. rapa, and C. tetrahit had the largest values, followed by C. album and S. media with medium values, and V. arvensis with the smallest values. As for leaf area and dry weight, S. media took more advantage of the low than the high irradiance level compared with C. album. Species differences are discussed with regard to competitive ability.
The effect of nitrogenous compounds on in vitro germination of Orobanche crenata Forsk.
Authors: VAN HEZEWIJK M. J. , VERKLEIJ J. A. C.
Published: July 2006

The effect of nitrogen (ammonium, urea and nitrate), applied during a conditioning or germination phase, on germination of Orobanche crenata Forsk, seeds was investigated in vitro. Ammonium sulphate (8 mM) applied during conditioning in combination with the nitrification inhibitor nitrapyrin, reduced germination of seeds from 46% to 26%. A lower concentration of 4 mM ammonium sulphate or supplying nitrogen as 8 mM urea or 16 mM nitrate did not inhibit germination. Applied after conditioning during the germination phase, 4 mM ammonium sulphate strongly inhibited germination, especially in combination with a nitrification inhibitor: germination was reduced to less than 5%. Urea (8 mM) reduced germination to only a limited extent (from 58% to 40%). When a urease inhibitor (carbon disulfide) was additionally applied, germination percentage was not affected. Nitrate had no effect. It is hypothesized that the inhibition by ammonium of O. crenata germination is connected with a reduced ability to detoxify ammonium, owing to the reduced activities of the enzymes GS and GOGAT. The inhibitory effect of urea may be indirect, occurring through conversion to ammonium. The effect of a short‐term exposure to ammonium was largely reversible and no increase in mortality could be detected. The presence of 6 mM phosphate, Hepes or Mops buffer was found to intervene with the inhibition by ammonium.
Alcoholysis and chemical hydrolysis of bensulfuron‐methyl
Authors: SABADIE J.
Published: July 2006

Alcoholysis (methanol or ethanol) and hydrolysis (pH ≤ 8) of the herbicide bensulfuron‐methyl at 30 or 50^C involve only the breakdown of the urea part of the molecule. A high yield of the pyrimidinamine is always obtained, along with the corresponding carbamate (alcoholysis) or benzylsulfonamide (hydrolysis). The latter compound was easily cyclized (pH ≥ 6). In alkaline solution, the carbomethoxy substituent of the aromatic ring was preferentially hydrolysed. In all cases, the alcoholysis and hydrolysis rates could be described well with first‐order kinetics. Alcoholysis rate constants of bensulfuron‐methyl and bensulfuron ranged from 0.08 to 0.15 d−1 at 30^C. Hydrolysis rate constants of bensulfuron‐methyl, bensulfuron and benzylsulfonamide varied strongly with pH. The hydrolysis rate constant of bensulfuron‐methyl was minimal around pH 8. The hydrolysis rate constant of bensulfuron decreased with increasing pH, whereas that of benzylsulfonamide increased with increasing pH.
The importance of seeds and sexual reproduction in the population biology of Cirsium arvense ‐ a literature review
Authors: HEIMANN B. , CUSSANS G.W.
Published: July 2006

In this review the available information on the sexual reproduction of Cirsium arvense L. (Scop.) is summarized and discussed in an ecological context. Certain aspects of its sexual reproduction system have given C. arvense a reputation for low efficiency: the dioecious mating system and dependence on insects for pollination and non‐adaptive features for wind dispersal. The seeds are moderately persistent in soil and, for a temperate weed, have a high temperature requirement for germination. It is concluded that the contribution that sexual reproduction makes to the survival and spread of this species has been underestimated, partly owing to an inadequate number of studies. Seedling recruitment via sexual reproduction may be an important mechanism for initiating continued genetic diversity at intra‐ and inter‐population levels.
An assessment of the possible reasons for differential tolerance to fluroxypyr in selected populations of Galium aparine
Authors: HILL A. L. , COURTNEY A. D. , HARVEY B. M. R.
Published: July 2006

In an investigation of the possible reasons for tolerance lo fluroxypyr by Galium aparine L. (cleavers), a wide range of variation in total herbicide retention was exhibited by nine diverse populations from throughout Europe. Although these differences in fluroxypyr relention became negligible when considered on a unit area basis, a two‐fold difference was maintained per unit dry matter. There was no difference in fluroxypyr uptake between a fluroxypyr‐tolerant and a fluroxypyr‐susceptible population, and differences in translocation between the two populations did not seem to explain the differential tolerance. It is suggested that differential metabolic detoxification may be the main reason for the variation in response to fluroxypyr by populations of G. aparine.
Resistance of Amaranthus hybridus to atrazine
Authors: SEREDA B. , ERASMUS D. J. , COETZER R. L. J.
Published: July 2006

Resistance of weeds to triazine herbicides has been recorded in many countries. The extent of the problem in South Africa is uncertain. In a pilot study, the atrazine resistance of Amaranthus hybridus L. (smooth pigweed) was investigated. Suspected resistant (R) and susceptible (S) biotypes were treated with commercially formulated atrazine. After post‐and pre‐emergence applications under tunnel conditions, it was found that the suspected R biotype plants were not affected at herbicide dosages of belween 1.25 and 25.0 kg a.i. ha‐1, i.e. up to 20 times gieater than the lowest recommended dosage. However, the S biotype plants were killed by the lowest dosage. In the fieid, mortalities in the R biolype were not observed after post‐emergence applications of 1.25‐10.00 kg a.i. ha‐1. In contrast, all S biotype plants were killed. In tunnel experiments, the R biotype was also found to be resistant to cyanazine and cyanazine+atrazine, while slight tolerance to linuron was observed. All these treatments resulted in 100% mortality of the S biotype. Although S biotype seeds oi A. hybridus were found to germinate slightly sooner under controlled conditions than R biotype seeds, preliminary results suggest that there are no major differences. Indications are that, although the growth of the S biotype may be greater than that of the R biotype, the competitive effect of the two biotypes on crop seedlings may well be similar.
Characteristics of seeds and seedlings from weeds treated with sublethal herbicide doses
Authors: ANDERSSON L.
Published: July 2006

Size, germination and viability of seeds as well as growth of seedlings derived from three weed species were studied in a pot trial. Fallopin convolvulus (L.) A. Loeve, Galium. spurium L. and Thlaspi arvense L. were treated with MCPA or tribenuron‐methyl at four doses and at five growth stages, from seedling stage to flowering, In G. spurium subnormal doses of tribenuron‐methyl, applied at intermediate growth stages, greatly reduced seed weight, gennination, viability, seedling shoot biomass and root biomass. Germination and viability, as well as the shoot biomass and root biomass of seedlings, were highly correlated with seed weight. In addition, but to a smaller extent, seed weight was reduced in F. convolvidus and T. arvense by tribenuron‐methyl and in G. spurium by MCPA. Germination was reduced in F. convolvulus by MCPA and in T. arvense by tribenuron‐methyl. However, the effects varied greatly depending on the growth stage at application.
Biological activity, field persistence and safe recropping intervals for imazethapyr and rimsulfuron on a silty‐clay soil
Authors: ONOFRI A.
Published: July 2006

Greenhouse and field trials were carried out from 1990 to 1993 on a silty‐clay soil in central Italy to assess the risk of carry‐over of imazethapyr and rimsulfuron residues. Turnip and sunflower were the most sensitive species to rimsulfuron residues (damaging thresholds lower than l ng a.i. g‐1), whereas sugar beel. turnip, oilseed rape and grain sorghum proved to be the most sensitive species to imazethapyr (damaging thresholds ranging from 0.5 to 6 n g a.i. g‐1). The time required for 50% imazethapyr disappearance (DT50) from the upper soil layer (0‐0.1 m)ranged from 18 to 21 days, whereas the DT50for rimsulfuron ranged from 5 to 6 days. Safe recropping intervals on soil treated with imazethapyr (rate of 35 g a.i. ha‐1) ranged from 3–4 weeks for the least sensitive species (maize, sunflower and mustard) up to 5–6 months for the most sensitive ones (sugar beet and turnip). For rimsulfuron (rate of 15 g a.i. ha‐1), recropping intervals of 2–3 weeks proved to be long enough to avoid injuries to any crops, except for the most sensitive species (turnip), which required 6 weeks before it could be safely sown in treated fields. Simple greenhouse bioassays allowed reliable predictions to be obtained about injuries observed in the field, confirming their usefulness to forecast the risk of carry‐over of residues.
Penetration of triolein and methyl oleate through isolated plant cuticles and their effect on penetration of [14C]quizalofop‐ethyl and [14C]fenoxaprop‐ethyl
Authors: SANTIER S. , CHAMEL A.
Published: July 2006

The penetration of two model seed oil compounds, [14C]triolein (TRI) and [14C]methyl oleate (MEO) through plant cuticles and their effects on the penetration of [14C]quizalofop‐ethyl and [14C]fenoxaprop‐ethyl were investigated. Experiments were carried out using isolated cuticles from rubber plant (Ficus elastica Roxb.) leaves and from tomato (Lycopersicon esculentum Mill,) and pepper (Capsicum annuum L.) fruits. Chemicals were deposited in droplets on to cuticle discs maintained on agar blocks under controlled conditions. TRI and MEO were used at 1% (V/V). The transfer of radiolabel through cuticles was negligible for TRI and varied from 6 to 13% after 72 h, according to species, for MEO, The penetration results obtained for quizalofop‐ethyl (0.084 mg mL‐1) and fenoxaprop‐ethyl (0.189 mg mL‐1) were very similar and varied according to species. The greatest diffusion intoagar was observed for pepper (12.8% and 10.7% after 72 h, for quizalofop‐ethyl and fenoxaprop‐ethyl respectively), the lowest for rubber plant cuticles (1.4 and 1.3% respectively). Addition of MEO produced significant increases in the penetration of quizalofop‐ethyl and fenoxaprop‐ethyl through rubber plant and tomato cuticles. TRI had an enhancing effect on the two herbicides only with rubber plant cuticles. Results are discussed with particular consideration of the variations between plant species and the possible mode of action of seed oil adjuvants.
A review of the role of fire in nutrient cycling in Australian native forests, and of methodology for studying the fire‐nutrient interaction*
Authors: RAISON R. J.
Published: July 2006

Previous studies relating to the effects of fire on nutrient cycling in Australian native forests are reviewed. It is apparent that: (a) the action of fire on soil fertility is likely to be important in affecting the functioning of Australian plant communities, (b) work to date only gives a guide as to the nature and magnitude of the effects of fire on some nutrient pools and nutrient cycling processes, but has not established the significance of such effects to the nutrient budget of entire forest systems, or established the links between fire, soil fertility and the functioning of forest communities.

The difficulties associated with studying and predicting the long‐term effects of fire on the fertility of forest soils are discussed. A new methodology applicable to study of the interaction between fire and plant nutrition is advocated, and is based on examination of the effects of fire on nutrient stores and flux rates in the soil‐litter compartment of the forest. This approach emphasizes the use of changes in rates of nutrient cycling processes as an index of the‐effects of disturbances such as fire on a forest ecosystem. The application of the methodology in a study of the effects of repeated low‐intensity prescribed burning on soil fertility is discussed briefly.
Hydrology and fish diversity of a North Queensland tropical stream
Authors: BEUMER J. p.
Published: July 2006

Abstract

The diversity and distribution of fish and the hydrology of the Black‐Alice River System, North Queensland, are described from a 2‐year study (September 1972 to August 1974). Most physico‐chemical parameters measured exhibited seasonal patterns which are influenced by rainfall and discharge. A total of forty‐one species of fishes belonging to four groups: freshwater tolerant, saltwater tolerant, diadromous and sporadic, were recorded during the study. The diversity of fish species decreased with increasing distance from the mouth of the system. Fluctuations in total diversity (H') were due to variations in ‘species richness’ (D) rather than to equitability (E). The ability of the fish community to ‘recover’ its diversity and longitudinal distribution after a flood of above‐average magnitude is demonstrated.
Natural physical disturbance and predation: their importance in structuring a marine sessile community
Authors: MORAN P. J.
Published: July 2006

Settling panels were used to determine the distribution of sessile organisms. Experimental and control cages were located at two study sites that were of different physical exposures. Twenty‐nine species of sessile organisms were recorded for the two sites. Data on the presence or absence of each species, for each sample, were classified.

The resulting hierarchy showed natural physical disturbance to be the major structuring factor in the community.

Predation was of less importance in the physically stressed study site and had no effect on species distribution in the protected site.
Field studies of nitrogen fixation of Australian alpine plants and soils
Authors: CARR D. J. , CARR S. G. M. , PAPST W. R.
Published: July 2006

Alpine grassland areas in Victoria and New South Wales have been subjected to summer grazing by cattle and sheep for well over a hundred years. Legumes other than a few species of shrubs, which provide a very small percentage of the vegetation cover in the grasslands, are absent. Other alpine communities include Sphagnum ‘mossbeds’ in the valleys and areas of snowgum woodland and shrubland. Virtually nothing is known of the mineral status of these communities and nothing of their nitrogen economy. On the Bogong High Plains, enclosure of grassland and of Sphagnum mossbeds from grazing and trampling has resulted, in the last few decades, in considerable changes in both cover and composition of the vegetation.

A portable gas chromatogram was used to carry out determinations of the capacity of samples of the grassland and Sphagnum to support acetylene reduction to ethylene, by convention equated to a capacity to fix nitrogen. There appears to be a substantial capacity for acetylene reduction associated with the rhizosphere of the grasses (Poa australis agg.).

The capacity of the Sphagnum for acetylene reduction is even greater and appears to be due to facultative anaerobes, abundant only in the upper, living part of the Sphagnum. These organisms may depend in part on leakage of photosynthate from the living Sphagnum. Associations of Sphagnum with blue‐green algae appear to be unusual in contrast with work on Swedish subarctic mosses, which is discussed.

The only non‐leguminous Australian alpine plant so far examined for nitrogen fixation is Podocarpus lawrencei. A capacity for acetylene reduction was found for neither the nodules of the roots of this plant nor the associated soils.
The diet of the New Holland honeyeater, Phylidonyris novaehollandiae
Authors: PATON DAVID C.
Published: July 2006

New Holland honeyeaters collect nectar, manna or honeydew for energy and hawk small flying insects for protein. The insects taken were usually Diptera and Hymenoptera weighing 0.7 mg dry weight or less. Net rates of energy gain from hawking small flying insects were usually less than 20 J min−1 and sometimes negative and insufficient to meet the bird's daily energy requirements. Those from feeding on nectar, manna or honeydew were usually above 40J min−1 and often above 400J min−1 at dawn and the birds depended on these carbohydrates for energy. Nectar, manna and honeydew contained negligible amounts of protein, and the birds used small flying insects as sources of protein, and presumably other nutrients. Given that carbohydrate resources supply better rates of energy gain than insects. New Holland honeyeaters should collect their energy requirements from carbohydrates and only collect sufficient insects to satisfy their protein requirements. Estimates of the food intakes of both non‐breeding and breedig birds showed that they did this. Non‐breeding New Holland honeyeaters collected from 72 to 125 (mean 92) kJ of carbohydrates per day and 17 to 58 (mean 31) mg of protein per day. These meet the daily energy (75 kJ) and protein (20 mg) requirements of the birds. Breedig birds collected more carbohydrates and more insects, but in proportion to their increased energy and protein requirements respectively.

New Holland honeyeaters are probably limited by their ability to meet their energy requirements from nectar, manna or honeydew and not by insects. Non‐breeding birds collected their protein requirements in about 10 min of insect‐feeding, but spent from 33 to 90% of the day collecting carbohydrates to meet their energy requirements. The maintenance requirement of 20 mg of protein per day for New Holland honeyeaters is about 25% of that estimated from standard equations for a bird of the same size. This low level may have evolved in response to low energy availability.
Seed predation in native legumes of south‐eastern Australia
Authors: AULD TONY D.
Published: July 2006

Seed predation in 28 species of native legumes in the Sydney region was examined. While bruchids are significant seed predators in the Sydney region they are not the dominant seed predators group, as is the case in central America. Other important groups include weevils, anthribids and lepidopterans. In each group of seed predators studied, apart from the lepidoptera, a particular genus was closely associated with a single plant genus. The degree of seed predation varied from 85% to 3%, with only six of the 28 species of plants studied relatively free from seed predation (less than 10% seed‐crop losses). Variation in the degree of seed predation both within and between plant genera could not be explained by taxonomic relationships, morphology, distribution, seed weight or seed dispersal agents. A larger data base is necessary to account for such variations.
Phytophagous insect communities in the canopies of three Eucalyptus forest types in south‐eastern Australia
Authors: OHMART C. P. , STEWART L. G. , THOMAS J. R.
Published: July 2006

Intensive sampling of tree canopies for phytophagous insects was carried out in three contrasting eucalypt forest types comprised of species widely distributed in sub‐alpine forests in Victoria and New South Wales (Eucalyptus delegatensis, E. dives, and E. pauciflora). The number of phytophagous insects present in the canopies of these forest types was low, with a seasonal average of 20 individuals per kg of foliage (dry weight). Numbers were much lower than expected from past literature reporting‘chronically high’levels of defoliation in eucalypt forests.

Microlepidoptera, Geometridae, Chrysomelidae, and Curculionidae were the major leaf‐chewing groups recorded. Most sap‐feeders were either leafhoppers (Cercopidae and Cicadellidae) or in the superfamily Fulgoroidea. Psyllidae and gall‐making species were rare. Leafhoppers made up a very large portion of the phytophagous insect communities in each forest type, particularly in the E. dives forest. Microlepidoptera was the most commonly encountered defoliator group in all three forest types making up 33‐44% of the total count. Non‐phytophagous arthropods accounted for 44‐48% of all individuals encountered. The density of insect defoliators was greater in the lower crown than upper crown.

The E. dives canopy supported many more phytophagous insects per unit weight of foliage, as well as more per hectare, than the other two forest types. The greatest number of phytophagous species was also encountered in E. dives canopy. The E. delegatensis canopy supported the lowest number of phytophagous insects per unit weight of foliage as Well as numbers per hectare.

Abundance of insect defoliators in the eucalypt forest types in this study was similar to published figures of insect defoliators in northern temperate forests.
The occurrence of mixed stands of the Eucalyptus subgenera Monocalyptus and Symphyomyrtus in south‐eastern Tasmania
Authors: DUFF G. A. , REID J. B. , JACKSON W. D.
Published: July 2006

Mixed stands of eucalypts were examined on several sites in south‐eastern Tasmania. Species from the subgenus Monocalyptus (E. puchella and E. obliqua) became dominant over species from the subgenus Symphyomyrtus (E. viminalis and E. globulus) as the age of the stand increased. In glasshouse trials, Symphyomyrtus species were initially at an advantage since they were more opportunistic than Monocalyptus species owing to their more rapid and even germination and higher initial growth rates. In addition, the Monocalyptus species E. pulchella showed a greater tendency to regenerate vegetatively than the Symphyomyrtus species E. viminalis and E. ovata.
The role of soil mobility in controlling a vegetation gradient
Authors: BUCKLEY RALF C.
Published: July 2006

Mature plants of species which characteristically occupy the mobile crests and upper slopes of the central Australian sandridges are more tolerant of sand burial or undercutting than those of the lower slopes and swales. Seedlings growing on the mobile crest areas are susceptible to sand burial, even during wet years. The young shoots of vegetatively spreading species are less susceptible than individual seedlings of the same size.
Seasonal and diurnal variations in the energetics and foraging activities of the brown honey eater, Lichmera indistincta
Authors: COLLINS BRIAN G. , BRIFFA PETER
Published: July 2006

In general, the brown honeyeater, Lichmera indistincta, flies more and expends more energy when visiting flowers in the early morning than at other times. Floral nectar is most abundant early in the day, and nectar energy intake by L. indistincta is greatest at that time. It appears as if birds can only store excess energy during the early part of the day, incurring energy deficits at other times. Unit perching and flight costs are greatest for L. indistincta in winter and spring. As a result, peak total energy expenditures and requirements occur at these times, birds apparently being unable to reduce energy demands by employing nocturnal torpor. Estimates of probable energy uptake by L. indistincta from the plant species studied exceed predicted requirements in all seasons except winter, when it is apparent that birds would need to be especially selective in the plants that they used as major energy sources.
Populations of the bush fly (Musca vetustissima Walker) in arid Australia
Authors: MATTHIESSEN J.N.
Published: July 2006

Populations of the bush fly Musca vetustissima were usually low in arid south‐western Australia. Herbaceous plants that grew only after rain resulted in changes to cattle dung that increased its attractiveness to bush flies for oviposition in laboratory tests. Larvae reared in such dung consistently produced large flies of high fecundity, and larval survival was usually high. Similar responses to the dung were evident from examination of flies sampled in the field. Although greatly increased bush fly abundance was possible only after major improvement in cattle dung, it was not a general phenomenon as immature survival did not always increase. Even major population increases resulted from periods of high immature survival that were brief relative to the duration of favourable dung. Nematodes Heterotylenchus sp. appeared to be an important mortality factor of the immature stages at such times.

Build‐up of high bush fly populations occurred only in cattle‐grazing areas, but base‐level abundance was similar regardless of the presence of cattle. Almost all female flies were gravid when cattle dung was unfavourable for breeding, and in areas without cattle. In arid areas, acceptable oviposition sites probably are more limiting than are sources of protein for oögensis.
A radar and aerial‐trapping study of an early spring migration of moths (Lepidoptera) in inland New South Wales
Authors: DRAKE V. A. , FARROW R. A.
Published: July 2006

The migrations of a number of species ofnoctuid and pvralid moths were studied with a specialpurpose radar unit and by direct sampling with a kite‐borne net at a locality in central‐western New South Wales during the early spring of 1980. The observations coincided with the appearance of very large numbers of moths throughout much of south‐eastern Australia, and immediately followed a major caterpillar plague in south‐western New South Wales. The migrations occurred mainly at night, and were most intense during periods of warm weather. Several different directions of migration were observed, but the movements were always approximately downwind; distances of a few hundred kilometres were typically covered during a single night. A number of quantitative measures of the migration intensity have been estimated for some of the flights. The migrating population frequently exhibited a degree of mutual alignment, which was sometimes in a direction different from that of the migration. Migrants became concentrated into layers at high altitudes (up to 1900 m) on two occasions during the night. Similar high‐altitude migrations were also detected during daylight. It is inferred that an early spring re‐invasion of drought‐affected inland areas, and of areas on the continental periphery which have a cool winter climate, by means of long‐distance migrations from inland areas where autumn and winter conditions have been favourable for larval development, is an almost regular feature of the population dynamics of several moth species that are of economic importance in south‐eas‐tern Australia. These migrations are interpreted as an adaptation to the geographie and climatic factors that control larval development and moth flight in this region, and especially to the erratic rainfall regime of the inland source areas.
Winter energy deficits and the importance of fruit versus insects in a tropical island bird population
Authors: CATTERALL CARLA P.
Published: July 2006

The sedentary population of 200 to 500 silver‐eyes on Heron Island, Australian Great Barrier Reef, experiences high mortality during the winter non‐breeding season. The omnivorous silvereyes feed mainly on small insects gleaned from foliage, and on fruits, especially the fig Ficus opposita. Estimates of the energy content of food items reveal that small insects (2–5 mm long) provide little assimilable energy (9 J), whereas large insects (>8 mm) and bites of fig provide most assimilable energy (217 J and 181 J respectively).

An analysis of the average daily intakes and expenditures (estimated by the time‐budget method) for three sampling occasions showed that the rates of insect consumption (10,15 and 11 kJ day‐1) were significantly less than the energy requirements (37, 38 and 37 kJ day‐1). While many individuals may have been able to balance their energy budgets by eating figs, the calculated fruit intake rates (38, 9 and 0.5 kJ day‐1 respectively), together with high inter‐individual variation in fig consumption, suggest that figs were often in short supply. The birds visited fig trees most frequently during the first 2 h after sunrise, and the feeding success rate in fig trees (approximately 20% of visits successful) during this time was significantly greater than that during the rest of the day (approximately 10% of visits successful). Alternative hypotheses for these patterns, based on protein requirements, on diurnal rhythms imposed by insect availability, or on satiation, are considered and rejected.

These results indicate that the pre‐breeding population size is limited by winter energy shortage, the extent of which is dependent on the size and phenology of the fig crop. Natural selection should favour individual strategies for maximization of net energy intake.
Rates of litterfall and organic matter turnover at three South Australian indigenous forest sites
Authors: HUTSON BARRY R.
Published: July 2006

A quantitative study of the litterfall rate, litter mass and the organic carbon content of litter and soil at three South Australian low open‐forests was made monthly for 2 years. The soil and dominant vegetation at the sites were similar, but the mean annual rainfall differed; 635, 690 and 1050 mm respectively at the ‘dry’, ‘medium’ and ‘wet’ sites.

Mean annual litterfall at the dry, medium and wet sites was 114, 205 and 233 g m−2 respectively, and the mean mass of the litter layer was 885, 1153 and 858 g m−2 Leafy material formed 82% of the litterfall at each site and maximum fall occurred in the summer. Leafy material formed 64–68% of the three litter layers and there was no general pattern of seasonal change of mass.

The data obtained were used to calculate the half‐life (T1/2 of the litter, the values were 5.4, 3.9 and 2.6 years respectively at the dry, medium and wet sites. The values from the medium and wet sites fit within the range previously recorded for other open‐forests and low open‐forests, but indicate an extremely slow rate of decomposition at the dry site, which was located close to open‐scrubland.

The amounts of organic carbon in the 0–8 cm layer of soil at the dry, medium and wet sites were 777, 928and 950 g m‐2 respectively. However, without a detailed investigation of the source of soil carbon, these values could only be used to show that the organic carbon store to a depth of 8 cm is equivalent to 9–15 times the annual litterfall input.
A correction to the equations describing the McArthur forest fire danger meter
Authors: SIRAKOFF CHRISTINA
Published: July 2006

The addition of a limit to the drought factor used it the equations describing the McArthur forest fire danger meter Mark 5 gives an improved estimation of forest fire behaviour.
Seasonal prevalence of adult mosquitoes at Casuarina and Leanyer, Darwin
Authors: RUSSELL RICHARD C. , WHELAN PETER I.
Published: July 2006

Mosquito populations were sampled fortnightly for 2 years, using EVS solid CO2 baited light traps, to monitor seasonal activity of females in the vicinity of new urban development at Casuarina Swamp and Leanyer Swamp, Darwin. The relative abundance of different species was related to seasonal conditions and the influence of urban stormwater on the larval habitats within the two environments.

Differences were observed between sites due to the site ecology, and between years and between seasons but, in general, the early dry season was dominated by Culex annulirostris, Anopheles bancroftii and An hilli, while Aedes vigilax and Cx annulirostris were predominant in the late dry season and early wet season at both sites. The late wet season at Leanyer Swamp was dominated by An hilli and An bancroftii, while at Casuarina Swamp, Cx annulirostris was the predominant species. The prevalence of vector species indicates the need for control measures to protect the local communities from mosquitoborne disease.
Vegetation‐soil relations in the lowlands of south‐west Tasmania
Authors: BOWMAN D. M. J. S. , MACLEAN A. R. , CROWDEN R. K.
Published: July 2006

A geographic survey of 14 south‐west Tasmanian sedgeland‐heaths revealed that soil organic matter is related to: water content: total nitrogen (N): total and exchangeable sodium (Na), calcium (Ca) and magnesium (Mg); exchangeable potassium (K) cation exchange capacity; and total exchangeable bases. However, total and available phosphorus (P), total K and Iron (Fe). pH level and percentage base saturation were found to be Independent of organic content. Most of the soil nutrient capital is contained In the A0 horizon, the depth of which was found to be positively related to the time elapsed since the last fire. There is no clear relationship between rock type and soil fertility, but there is evidence of soil‐vegetation interaction. The sedgeland‐heath species have lower concentrations of P, Ca and Mg in their foliage and are more efficient In the withdrawal of P and K upon tissue senescence than the surrounding scrub and forest species. Over a vegetation transition from sedgeland‐heath to forest on uniform geology there was a change in soil type. The forest was found to have more fertile soils and a higher concentration of nutrients in the above‐ground biomass than the adjacent sedgeland‐heath. The ecotone was burnt between 20–30 years prior to sampling, but the fire did not kill all the forest trees, and the structural differences suggest a mare rapid recovery of forest species. Soil fertility appears to be an important factor in controlling the rate of recovery and succession following a fire, especially if the nutrient‐rich organic layer is burnt.
Light interception and its relation to structural differences in three Australian rainforest canopies
Authors: LOWMAN M. D.
Published: July 2006

Relative differences in the seasonality of light penetrating the canopies of three Australian rainforests were measured directly with a quantum meter and indirectly using hemispherical photographs. The mossy microphyll fern forest had higher incident light levels (100–200 μEinstein m−2 per s) and more sky visible (21.8%) at ground level than the simple (5–20 μEinstein m−2 per s with 11.2% skylight) and complex (5–10 μEinstein m−2 per s with 10.8% skylight) notophyll vine forests. There were no significant changes in amounts of sky visible through the canopy over time (10 months) for any canopy, despite the fact that leaf‐fall was a seasonal event. Profile diagrams were constructed at each site to illustrate the depth and stratification of the canopy, and the differences in these structural features were related to the variation in light attenuation. Ecological aspects of light interception through rainforest canopies are discussed, including tree branch growth patterns and leafing phenologies, and seedling regeneration on the forest floor.
Patterns of morphology and behaviour in a cicada guild: A neutral model analysis
Authors: MACNALLY RALPH C. , DOOLAN JANE M.
Published: July 2006

Morphological and behavioural patterns were examined in a guild of nine species of eastern Australian cicadas. Co‐occurrence in, and structure of, 44 study plots were determined to relate morphological and behavioural patterns to habitat overlap and habitat structure. Multi‐variate analyses were employed to generate relationships between the species. Guild substructure shown by the habitat analyses cannot be predicted from the group substructure indicated by the morphology/behaviour analyses. Therefore, extant combinations appear to be random collections from the nine‐species pool insofar as morphology and behaviour are concerned. In particular, the most generalized species (in terms of habitat) are relatively extreme in morphology and behaviour, and vice versa. Despite these results, there are weak indications that at least two suites of characters exist, and that one of them is associated with each of the most extreme types of habitat. The reasons for these apparently contradictory results are discussed. There is no evidence to suggest that systematic morphological divergence has occurred in this guild.