Integrating in situ quantitative geographic information tools and size‐specific,laboratory‐based growth zones in a dynamic river‐mouth estuary

• 1. The ultimate determination of coastal habitat suitability requires the integration of both dynamic (i.e. water mass characteristics) and stationary (structural) habitats. An approach using real‐time streamed data collection, remote sensing, and GIS modelling to compare and contrast seasonal and spatial patterns in these habitat components of the eastern and western distributaries of the lower Pascagoula River estuary is described.
• 2. Structural and dynamic habitat characteristics are described using GIS and integrated with published growth data on juvenile mullet (Mugil spp.) and spot (Leiostomus xanthurus) to reveal zones of accelerated growth. Both mullet and spot had their greatest growth when water temperature and salinity (dynamic habitat) were physiologically optimal. The lack of spatial difference in the dynamic habitat between distributaries resulted in no growth zone differences for both species.
• 3. The integration of the growth zones with the structural habitat component showed that the west distributary, with its greater availability and reduced fragmentation of main channel marsh edge, should provide a greater area of essential fish habitat than the east distributary for juvenile spot, a marsh‐edge associate. Because juvenile mullet are less associated with structural wetland habitat, growth zones and the stationary (structural) habitat were not integrated.
• 4. The approach of integrating real‐time geo‐referenced water quality data with regional fish growth‐rate data is an important step towards a quantitative understanding of the hierarchical nature and inherent variability of dynamic coastal environments. The use of this holistic approach should lead to more effective management of estuarine systems, especially in regard to potential impacts within the estuary's watershed and to its coupling with offshore environments.

Copyright © 2007 John Wiley & Sons, Ltd.     

Effects of stable dust on farm animals-a review

The relationship between air quality-its dust content-and respiratory diseases of animals in the food industry and otherwise in examined. The correlation between dust content and incidence of disease in farm animals is also discussed. Lesions caused either directly or indirectly by dusttransported microorganisms are reviewd. Effects of dust on animal performance are included.This review is an attempt to compile available information on the natural occurrence of stable dust and the possibilities for its measurement and control.     

Vepsuche zur Ermittlung der Inkubationszeit der Tödlichen Vergilbung der Kokospalme (Lethal Yellowing Disease of coconut palm) in der Wirtspflanze

Zusammenfassung Das Aussetzen von 24 Serien von Palmen in Kübeln in einem Krankheitsgebiet für eine beschränkte Zeit, 7 Sätze von 15–20 Palmen für einen Monat, 3 Sätze für zwei Monate und 14 Sätze für drei Monate, diente zur Ermittlung der Inkubationszeit für die Tödliche Vergilbung der Kokospalme. In den meisten Fällen, die zur Ansteckung im Krankheitsgebiet führten, lag die geschätzte Inkubationszeit zwischen 3 und 6 Monaten; nach dem aufgestellten Histogramm betrug die durchschnittliche Inkubationszeit 150–160 Tage. Die lange Expositionszeit bei der größeren Zahl der Sätze erlaubt keine genaue Festlegung der Zeitspanne. Nach Entfernen von Käfigen in einem zweiten Versuch, die als Schutz gegen Infektionen dienten, traten erstmals Symptome an Palmen nach 6 (1 Palme) und 7 (2 Palmen) Monaten auf. Unter Berücksichtigung, daß der Ausbruch einer Krankheit Schwankungen unterworfen ist und auß erdem wesentlich vom Infektionszeitpunkt abhängt, fügen sich diese Daten gut in die für die Inkubationszeit angenommene Zeitspanne ein.Bodenorganismen (Nematoden) scheiden als Überträger der Tödlichen Vergilbung aus, da die Palmen in Kübeln keinen Bodenkontakt hatten. Die Palmen in den Käfigen dagegen konnten, soweit sie in den Boden gepflanzt waren, mit ihren Wurzeln unter den Käfigrand vordringen und wären dadurch der Infektion zugänglich gewesen.Da nur in den Sätzen, die den Infektionsbedingungen eines Krankheitsgebietes zwischen den Monaten Februar und August ausgesetzt waren, einzelne Palmen in den Gruppen erkrankten, dürfte in dieser Zeitspanne der Ü berträger besonders aktiv oder in der übrigen Zeit des Jahres relativ selten sein, anders wäre die Häufung der Infektionen in diesen Monaten nicht zu erklären.

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Summary A transfer experiment using 17 sets of coconut palms, planted in drums and transferred bimonthly or three-monthly from a healthy into a diseased area (2 or 3 months exposure time) and 7 sets exposed for only a month, provided us with good information about the incubation period of Lethal Yellowing in a palm. The most probable incubation period ranges between 3 and 6 months; according to the dates on the histogram the mean incubation period appeared to be 150–160 days. The long exposure time used for most of the sets does not allow a more accurate assessment of this time interval.In a second experiment, groups of coconut palms which had been protected by cages for at least a year against infections were exposed to the natural infection conditions by removal of the cages. The first case of disease was recognized 6 months after cage removal, 2 additional cases a month later. Taking into consideration that the development of symptoms varies within a time interval depending upon the date of infection, growing conditions etc, this observation agress with the inferred incubation period gained in the transfer experiment.Soil organisms (nematodes o. a.) can be excluded as transmitters of the Lethal Yellowing pathogen. The palms used in the transfer experiment which later on showed symptoms were planted in drums; the roots having no connection with the soil in the field. The soil for filling the drums was collected in a healthy area. The roots of caged palms which were planted directly into the soil could penetrate under the cage border into the unprotected part of the plot which contained a lot of naturally diseased palms scattered across the field.Only sets of palms which were partly or fully exposed to the infection conditions of a diseased area during February to August developed a number of cases of Lethal Yellowing. The occurrence of infection during this period indicates this to be a time of particular vector activity.

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F.A.O.- Expert in Kingston, Jamaica; jetzt: Biologiche Bundesanstalt für Land- und Forwirschaft, Berlin-Dahlem.

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F.A.O.- Associate-Expert in Kingston (Coconut Industry Board.

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Biologische Bundesanstalt für Land- und Forstwirstchaft, 1 Berlin 33 Dahlem, Königin-Luise-Straße 19.     

Prediction of oriented strand board properties from mat formation and compression operating conditions. Part 2: MOE prediction and process optimization

A model to predict the bending modulus of elasticity (MOE) of oriented strand board (OSB) panels produced by batch processing is presented. The approach developed herein is unique in its comprehensiveness since the MOE is determined from information on the panel structure, temperature and moisture profiles and vertical density profiles obtained from the mat formation and compression models presented in Part 1. Comparison of predicted MOE values with those measured from 24 commercially produced panels shows good agreement considering some of the uncertainties involved. Simulations show that the MOE can be increased by any of the following changes: reduced fines content, increased panel density, better flake alignment in each of the three layers within a panel, increased flake length and a larger difference between the density of the face and core layers. The model was also used in a genetic algorithm to carry out an optimization study of batch OSB manufacturing. This analysis showed that by combining the appropriate reduction in the amount of flakes used, increase in fines content, improvement in flake alignment within each of the face and core layers and shortening of the batch time, a significant theoretical profit increase from the base case scenario can be obtained.     

Effects of induction treatments on flowering in Populus deltoides

Stimulation of early flowering is required to shorten breeding cycles of eastern cottonwood (Populus deltoides Bartr. ex Marsh. var. deltoides), a commercially important and fast-growing hardwood species. A series of experiments was conducted to evaluate the influence of various treatments on flowering in rooted cuttings from mature and juvenile trees. A combined treatment of water stress, root pruning and paclobutrazol was applied to 3-month-old rooted cuttings from mature trees. These cuttings had been subjected to root restriction and long days. All treated plants flowered, whereas no untreated plants formed flower buds. One-year-old rooted cuttings from juvenile trees did not flower when treated with either paclobutrazol, paclobutrazol plus water stress, paclobutrazol plus root pruning, or paclobutrazol plus girdling. This was true both under continuous or periodic growth. Assessment of the lack of flowering in juvenile trees may require an integrated approach that investigates environmental or physiological stimuli, assimilate shift, gibberellic acid type and concentration, and flowering-time gene activity in the new shoots of mature and juvenile cottonwood trees.     

Blight of conifer seedlings caused by Colletotrichum gloeosporioides

In a growth chamber experiment, 70-day-old seedlings of 10 conifer species were inoculated with Colletotrichum gloeosporioides conidia to determine the host range of the fungus. Based on the percentage of seedlings affected and the disease severity on individual seedlings, the order of most to least susceptibility was: western hemlock (WH), mountain hemlock, western larch, Sitka spruce, Engelmann spruce, Douglas-fir (coastal form, then interior form), white spruce and ponderosa pine; lodgepole pine and western red cedar remained unaffected. Inoculation of WH needles showed that within 24 h C. gloeosporioides conidia germinate and appressoria (penetration structures) form. A growth chamber study demonstrated that the pathogen can infect WH at needle wetness periods as short as 15 min; number of needles affected was higher at 0.5 h, but did not increase further even when wetness was extended up to 8 h. The results are discussed in relation to blight management of greenhouse-grown conifer seedlings.Portion of a Bachelor of Science (Honors) thesis, Department of Biology, University of Victoria, Victoria, British Columbia.     

Dry matter production and allocation in Eucalyptus cloeziana and Eucalyptus argophloia seedlings in response to soil water deficits

Effects of soil water availability on seedling growth, dry matter production and allocation were determined for Gympie (humid coastal) and Hungry Hills (dry inland) provenances of Eucalyptus cloeziana F. Muell. and for E. argophloia Blakely (dry inland) species. Seven-month-old seedlings were subjected to well-watered (100% field capacity, FC), moderate (70% FC) and severe (50% FC) soil water regimes in a glasshouse environment for 14 wk. There were significant differences in seedling growth, biomass production and allocation patterns between species. E. argophloia produced twice as much biomass at 100% FC, and more than three times as much at 70% and 50% FC than did either E. cloeziana provenance. Although the humid provenance of E. cloeziana had a greater leaf area at 100% FC conditions than did the dry provenance, total biomass production did not differ significantly. Both E. cloeziana provenances were highly sensitive to water deficits. E. argophloia allocated 10% more biomass to roots than did E. cloeziana. Allometric analyses indicated that relative biomass allocation patterns were significantly affected by genotype but not by soil water availability. These results have implications for taxon selection for cultivation in humid and subhumid regions.     

Evaluation of competition and light estimation indices for predicting diameter growth in mature boreal mixed forests

A series of conventional distance-independent and distance-dependent competition indices, a highly flexible distance-dependent crowding index, and two light resource estimation indices were compared to predict individual tree diameter growth of five species of mature trees from natural-origin boreal mixed forests. The crowding index was the superior index for most species and ecosites. However, distance-independent indices, such as basal area of competing trees, were also effective. Distance-dependent light estimation indices, which estimate the fraction of seasonal photosynthetically-active radiation available to each tree, ranked intermediate to low. Determining separate competition indices for each competitor species accounted for more variation than ignoring species or classifying by ecological groups. Species’ competitive ability ranked (most competitive to least): paper birch ≈ white spruce ≈> trembling aspen > lodgepole pine > balsam poplar. Stratification by ecosite further improved model performance. However, the overall impact of competition on mature trees in these forests appears to be small.