Die Ebersberger Waldordnung aus dem 13. Jahrhundert

Ohne Zusammenfassung     

Response of snails and slugs to fragmentation of lowland forests in NW Germany

Habitat fragmentation is a major cause for species loss, but its effect on invertebrates with low active dispersal power, like terrestrial gastropods, has rarely been studied. Such species can not cross a hostile habitat matrix, for which the predictions of island theory, such as positive relations between species richness and patch size, should apply. In order to test this prediction, we studied gastropod species diversity by assessing gastropod assemblage characteristics from 35 sites in 19 fragments of deciduous old-growth forests in the Lower Rhine Embayment, Germany. Assemblages differed between larger (≥700 ha) and smaller forests (<400 ha), those of large forests held a higher percentage of forest species. Although α-diversity was similar between the two forest size classes, small forests often comprised matrix species, resulting in a higher β-diversity. Edge effects on the species richness of matrix species were noticeable up to 250 m into the forest. Hierarchical partitioning revealed that distance to disturbances (external edge, internal edges like roads) explained most assemblage variables, whereas forest size and woodland cover within a 1 km radius from the sites explained only a few assemblage variables. Densities of two forest-associated species, Discus rotundatus and Arion fuscus, decreased with forest size. Yet, forest size was positively correlated with richness of typical forest species and densities of Limax cinereoniger. The latter species seems to need forests of >1,000 ha, i.e., well above the size of most fragments. In conclusion, the prediction is valid only for forest species. The response to fragmentation is species specific and seems to depend on habitat specialization and macroclimatic conditions. Jean-Pierre Maelfait: Deceased.     

Waldverbreitung und Waldeigentum im deutschen Raumplanungsrecht

Ohne Zusammenfassung     

Effects of Oral Administration of Specific Antibodies to Rainbow Trout Oncorhynchus mykiss

A new product called oralized fish serum concentrate (OFSC) was evaluated for a possible effect against various bacterial pathogens in rainbow trout. The OFSC produced from immune trout sera was found to contain fully functional antibodies and complement component C3. The antibodies detected in the serum concentrate were specific to Vibrio anguillarum (O1 and O2) and Aeromonas salmonicida , which had been used for vaccination of the fish prior to serum collection. The functionality of the specific antibodies in OFSC was not reduced after 6 wk storage at -20 C, 5 C, and 20 C. The serum was mixed with commercial trout feed and used for feeding rainbow trout fry (first feed period). After oral delivery of OFSC to rainbow trout for 1 mo, samples of gut content and gut tissue contained functional antibodies. In gutted fish no functional antibodies were found. This suggests that antibodies from OFSC are unable to be transferred across the gut wall in a functional state. Oral administration of OFSC did not increase survival of rainbow trout in an immersion challenge with Vibrio anguillarum .     

Comparison of greenhouse and environmentally controlled growthroom root growth potential testing of 2+0 eastern white pine seedlings

Two-year-old estern white pine (Pinus strobus L.) seedlings were measured for Root Growth Potential (RGP) in a hydroponic system over two years in both a greenhouse and an environmentally controlled growthroom. Analyses of variance showed no significant differences (alpha = 0.05) between testing environments for either year. This study demonstrates the validity of using greenhouse RGP testing for 2+0 eastern white pine.     

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.     

Polymerisation of added coniferyl alcohol by inherent xylem peroxidases and its effect on fungal decay resistance of Norway spruce

It is known that active peroxidase isozymes exist in mature wood of Norway spruce (Picea abies L. Karst.) and that they remain active for years and are found even in the heartwood (in Scots pine), where all cellular activity has ceased. This peroxidase activity was utilised in the impregnation of wood blocks with a natural monolignol, coniferyl alcohol and hydrogen peroxide. The hypothesis was that the internal wood peroxidases would oxidise the added monolignol and bind it stably into the cell wall matrix, which could hinder fungal decay. Since coniferyl alcohol is not very soluble in water, the impregnation was done under vacuum with an acetone–water solution containing 10% coniferyl alcohol and 0.4 mM H₂O₂ at room temperature (ca. 0.02 g of coniferyl alcohol was added to 1 g of wood). After impregnation, dimers of coniferyl alcohol and free coniferyl alcohol were found in acetone extracts with GC–MS analysis. Penetration of coniferyl alcohol and non-extractable reaction products were studied from the wood blocks with FTIR PAS technique. The wood samples treated were also subjected to a fungal decay test with Coriolus versicolor. This treatment hindered fungal decay in a 60-day experiment and led to a dry weight loss of 8.8% in comparison with 19.9% in the control. The reactions of coniferyl alcohol and H₂O₂ in the presence of peroxidases are discussed as well as the use of monolignols to increase wood decay resistance.     

Zur Repellentwirkung von Königskerzen auf Hausmäuse

Zusammenfassung Nach einer Mitteilung aus dem Ende des 18. Jahrhunderts sollen sich in Blüte stehende Pflanzen vonVerbascum thapsus als Mittel zur Vertreibung vonMus musculus undRattus norvegicus eignen. Eine Nachprüfung dieser Empfehlung mitV. thapsus, lychnitis undthapsiforme anMus verlief negativ.

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Summary At the end of the eighteenth centuryGoeze reports about the action ofVerbascum thapsus as a repellent againstMus musculus andRattus norvegicus. A revision of this information withV. thapsus, lychnitis andthapsiforme andMus musculus as test animals does not confirm his findings.

     

Variation in sugar maple root respiration with root diameter and soil depth

Root respiration may account for as much as 60% of total soil respiration. Therefore, factors that regulate the metabolic activity of roots and associated microbes are an important component of terrestrial carbon budgets. Root systems are often sampled by diameter and depth classes to enable researchers to process samples in a systematic and timely fashion. We recently discovered that small, lateral roots at the distal end of the root system have much greater tissue N concentrations than larger roots, and this led to the hypothesis that the smallest roots have significantly higher rates of respiration than larger roots. This study was designed to determine if root respiration is related to root diameter or the location of roots in the soil profile. We examined relationships among root respiration rates and N concentration in four diameter classes from three soil depths in two sugar maple (Acer saccharum Marsh.) forests in Michigan. Root respiration declined as root diameter increased and was lower at deeper soil depths than at the soil surface. Surface roots (0-10 cm depth) respired at rates up to 40% greater than deeper roots, and respiration rates for roots < 0.5 mm in diameter were 2.4 to 3.4 times higher than those for roots in larger diameter classes. Root N concentration explained 70% of the observed variation in respiration across sites and size and depth classes. Differences in respiration among root diameter classes and soil depths appeared to be consistent with hypothesized effects of variation in root function on metabolic activity. Among roots, very fine roots in zones of high nutrient availability had the highest respiration rates. Large roots and roots from depths of low nutrient availability had low respiration rates consistent with structural and transport functions rather than with active nutrient uptake and assimilation. These results suggest that broadly defined root classes, e.g., fine roots are equivalent to all roots < 2.0 mm in diameter, do not accurately reflect the functional categories typically associated with fine roots. Tissue N concentration or N content (mass x concentration N) may be a better indicator of root function than root diameter.