Über einen Zusammenbruch der Gelbhalsmauspopulation im Nationalpark Bayerischer Wald

Zusammenfassung Der Energiesto? eines guten Samenjahres der Fichte im Nationalpark Bayerischer Wald bewirkte bei M?usen im Frühjahr 1972 zun?chst eine starke Zunahme der Gelbhalsmaus. Nach dem Zusammenbruch dieser Population unter Stresserscheinungen, hervorgerufen durch Nahrungsverknappung und überbev?lkerung, trat im Herbst die R?telmaus st?rker in Erscheinung, die insbesondere an Laubh?lzern im Winter 1972/73 deutliche Spuren hinterlie?. Im Frühjahr 1973 dominierte nach einem schneereichen Winter bei sehr geringer Dichte die Erdmaus. Untersuchungen über die Nahrungswahl, Energie- reserven, Reproduktionsrate und Stresserscheinungen zeigten, da? die Populationsentwicklung der Gelbhalsmaus vorwiegend durch das Nahrungsangebot gesteuert wurde. Die Bev?lkerungsentwicklung der R?telmaus erschien dagegen von der Gelbhalsmaus negativ beeinflu?t oder durch nicht aufgedeckte endogene Faktoren geregelt. Es ergaben sich hier keine Hinweise für das Vorhandensein von Stressoren in der entscheidenden Vermehrungspause bis zum August 1972. Eine starke Zunahme der Adrenal- gewichte wurde erst im November bei h?chster Dichte und dem Einsetzen des Winters beobachtet.

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Summary Studies about a turnover of a Field-Mouse-population in the Bavarian National Park. In 1972 and 73 research work was carried out about population dynamics of the three most commonly species of rodents in the Bavarian National Park near the czech border: The Yellownecked Field Mouse (Apodemus flavicollis L.), the Bank Vole (Clethrionomys glareolus) and the Common Vole (Microtus agrestis L.). A great amount of spruce- seeds seemed to be most important for increased numbers of the Field Mouse trapped in the spring 1972 on all five localities (A, B, C, D and E) which were observed (Abb. 1). After the crash of this population in August 1972 by good weather conditions (Abb. 2) numbers of the Bank Vole were increased and this species was now most numerous in all localities (Abb. 1). In June 1973 the lowest density of all species was observed and the Common Vole dominated. This latter fact may be related to the high snow-cover until May 1973. Studies about ingested food-stuffs, body-fat content (Tab. 1) reproduction-rate (Abb. 3) and signs of stress (Abb. 4) showed, that the crash of the Field Mouse was caused primarly by detioration of food coupled with crowding effects. The population dynamics of the Bank Vole seemed interfered by the Field Mouse. No signs of stress were however detected during the recess of reproduction until August 1972 when the Field Mouse was dominating.

     

Reinvestigation of the proteolytically active components of Bromelia pinguin fruit

Pinguinain is the name given to a proteolytic enzyme preparation obtained from Bromelia pinguin fruits that has been scarcely studied. The present paper deals on the reexamination of the proteases present in fruits of B. pinguin grown in Cienfuegos, Cuba. The preparation (partially purified pinguinain, PPP) showed the main characteristics of the cysteine proteases, i.e., optimum pH within alkaline range (pH 7.2-8.8), inhibition of proteolytic activity by thiol blocking reagents, which is usually reverted by addition of cysteine, a remarkable thermal stability and notable stability at high ionic strength values. Isoelectric focusing and zymogram of PPP revealed the presence of several proteolytic components between pI 4.6 and 8.1. Preliminary peptidase purification by cationic exchange chromatography showed the presence of two main proteolytic fractions with molecular masses of approximately 20.0 kDa, according to SDS-PAGE.     

Signals of summer drought in crown condition data from the German Level I network

Crown transparency estimates of Scots pine, Norway spruce, common beech, pedunculate and sessile oak, annually surveyed between 1990 and 2004 within a grid over Germany, provide a suitable response variable to study drought effects on forest trees. Major climatic factors, available on a monthly basis as plot-specifically interpolated values and parameters of site and stand conditions, biotic and other relevant factors were used as predictors in different cross- and length-sectional, and longitudinal models. Stand age is a considerable and most constant driver of crown transparency in all species. Pine, spruce and beech responded—mainly with a delay of 1 year—with some foliar loss in areas where there was a surplus of temperature after the generally hot and dry summer of 2003. Parallel time-series analyses delivered species-specific geographic large-scale patterns with delayed or recent precipitation deficits or temperature surpluses. Even if beech is partly responding in current years with leaf loss towards precipitation surpluses, defoliation is especially high 1 year after hot summers, partly a result of high seed sets after such summers. Crown condition of oak responds in dry and warm areas according to the drought stress hypothesis, however, in cool and wet mountainous ranges oak responds after wet summers with higher defoliation. Longitudinal approaches revealed for all 4-tree species significant relationships between crown condition and deviations from the long-term means of temperature, precipitation but also global radiation and wind speed. Results do not always match the drought stress hypothesis, however, this is not to expect considering the heterogeneous site, stand and climatic conditions across Germany. Complex interactions of climatic and biotic factors also impede simple relationships. Soil-related clusters reveal higher sensitivity of spruce and beech towards climatic drought factors on more acid soils with thin humus layers. Also clusters constructed from plot-specific courses of defoliation reveal groups with rather closer relationships like a group of pine plots in the Oberpfalz, which seems to be especially sensitive to summer drought.     

European forest accounting: general concepts and Austrian experiences

Within the European Union there exist three different frameworks for forest accounting at the national level. For purposes of the national accounts, the regulations of the European System of Integrated Economic Accounts (ESA) have to be observed. They require a distinction between forestry and logging and provide specific guidelines for the valuation of standing timber. In recognition of the special character of forests and forestry production, two satellite accounts are devoted to forestry: the Economic Accounts for Forestry (EAF) and the European Framework for Integrated Environmental and Economic Accounting for Forests (IEEAF). Although they were designed as complementary to the national accounts and refer to the same basic methodologies, the guidelines for forest accounting provided by the three manuals are not fully compatible. Just recently, a further integration and harmonization of the concepts for forest accounting has been proposed. Austria has implemented the valuation of the increment as an output of forestry as requested by ESA and produces the EAF tables on a regular basis. The possibilities for extending forest accounting to natural resource accounts for standing timber and the IEEAF have been investigated in terms of pilot studies. The Austrian experiences and results exemplify the problems and possible solutions associated with the adoption of the different European schemes. Data deficits and valuation issues restrict the significance of respective results to some degree, especially as regards forestry-specific extensions of the accounting schemes.     

Influence of climate on radial growth of Pinus cembra within the alpine timberline ecotone

Radial growth variability and response to interannual climate variation of Cembran pine (Pinus cembra L.) were studied in the timberline ecotone on Mt. Patscherkofel (2246 m a.s.l.). The study area, which is in the inner alpine dry region of the Central Austrian Alps, is characterized by a continental climate with minimum precipitation in winter (about 150 mm during December-February) and frequent occurrence of warm dry winds (F?hn) in early spring. The hypothesis that spatial and temporal variability of radial growth is caused by site-related differences in sensitivity to winter stress (i.e., desiccation) was examined by applying dendroclimatological techniques. Ordination methods applied to tree ring time series revealed that spatial variability in radial growth is influenced by the local site factors elevation and slope aspect. Growth-climate relationships were explored using Pearson product-moment correlation coefficients and multiple regression analysis. Radial growth at the timberline was positively correlated with temperature in July and was also strongly correlated with mild temperatures in the previous autumn and high precipitation in winter (January-March). At the tree line, temperatures in the previous autumn and precipitation in late winter (March) also controlled radial growth, whereas July temperature was not significantly correlated with ring width. Because previous autumn temperature and winter precipitation were the main growth-determining factors at the timberline and the tree line, and both of these climate variables are known to influence susceptibility of trees to winter stress, the results support the working hypothesis. Analysis of climatic conditions in extreme growth years confirmed the high sensitivity of tree ring growth to precipitation in late winter (March) at the tree line plots. Furthermore, extent of growth reduction and release varied spatially and temporarily, with south- and west-facing stands showing a higher sensitivity to climate variation in the most recent decade (1990s) than the north-facing stand. This aspect-related change in sensitivity to climate may be associated with effects of climate warming on cambial activity.     

Nebenwirkungen von Toxaphen auf Maüse

Side-effects of Toxaphene of Mice. Albino-mice (swiss) and wild-captured voles and mice were given a high dose of 50 mg toxaphene (M 5055) per kg body weight daily for a period of some weeks or months. Three weasels and one ermine were fed on 300 of these sublethally poisoned mice without showing any negative effect. The following parameters of mice unpoisoned and poisoned with a sublethal dose of toxaphen were examined: mortality, number of litters, resorption rate of embryoes, growth, haematological values, activity of enzymes, amino acids and proteins in serum and urine. In the group of poisoned mice a slight increase of neutrophile blood cells (Tab. 2), a higher level of enzyme activities (SP, GPT, GT; Tab. 3) in serum and a typical change in uric proteins were observed. (Abb. 1).In the field 6 liters of toxaphen (M5055) were sprayed over a forest plantination of 1,5 ha for mouse control. The following development of mice, especially of the Common Vole (Microtus agrestis) was investigated with the capture, mark and recapture (CMR) method. Toxaphene had an influence on the parasitic complex of the vole for a long time. The number of fleas, mites, ticks, blood protozoa, grahemella and haemobartonella of the voles was reduced for more than 6 months in the treated area. This may be one reason for the fast recovery, good growth and increasing number of the voles observed after control with the insecticide toxaphene.

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Die Arbeiten wurden durch Mittel der Gesellschaft für Strahlen- und Umweltforschung (GSF), München-Neuherberg, unterstützt     

Evaluation of the effectiveness of Duddingtonia flagrans and Monacrosporium thaumasium in the biological control of gastrointestinal nematodes in female bovines bred in the semiarid region

Brazil has a herd of 212 million cattle and 171 million hectares of pastures that produce approximately 96 % of Brazilian beef. The Brazilian production system enables animal infection by endoparasites, which are considered one of the main obstacles for the development of this industry and are responsible for considerable economic losses. The control of parasitic diseases is performed via the administration of antiparasitic drugs, but they leave residues of the products in the treated animal, affect non-target organisms and select resistant strains of the parasites. The species D. flagrans and M. thaumasium are promising and sustainable alternatives for controlling gastrointestinal helminths of ruminants and other herbivores. In this study, we evaluated the efficacy of isolates of these species, formulated in a sodium alginate matrix and administered twice a week, to reduce the number of environmental infective larvae of gastrointestinal nematodes that affect prepubescent zebu females. The treated animals presented fewer eggs and a lower number of infective larvae per gram of faeces (p?<?0.05). The pastures occupied by treated animals showed a statistically significant reduction (p?<?0.05) of the number of L₃ and, furthermore, the genera Cooperia sp., Haemonchus sp., and Oesophagostomum sp. were the most prevalent. The average weight of the animals did not differ statistically (p?>?0.05) among the treated and control groups. The use of sodium alginate pellets as vehicle for delivery of the fungus mycelia D. flagrans (isolate AC001) and M. thaumasium (isolate NF34A) proved effective in controlling trichostrongylids in prepubescent cows bred in the semi-arid region, with an effective reduction in the number of infective larvae in the pastures.     

Effects of the needle bladder rust (Chrysomyxa rhododendri) on Norway spruce: implications for subalpine forests

Norway spruce trees in the subalpine forests of the European Alps are frequently attacked by the needle rust Chrysomyxa rhododendri. The obligate parasite undergoes a complex life cycle with a host shift between rhododendrons (Rhododendron sp.) and Norway spruce [Picea abies (L.) Karsten] and causes a yellowing and defoliation of the current-year needles in summer. Infected trees show several anatomical, morphological and physiological modifications, including a decrease in pigment content and net photosynthesis of infected needles, lower biomass production and reduced radial and height growth. The consequences are diminished timber yield and cripple growth. Because of repeated heavy infections in recent years, forest managers report increasing difficulties in both natural regeneration and afforestation at high elevation sites, where rhododendrons occur. This review gives a summary of the present knowledge about the effects of C. rhododendri infections on Norway spruce, including so far unpublished findings and with particular attention to the phenomena of resistant trees. Implications for subalpine forests and counter strategies are discussed.     

Application of an electrophoretically detectable genetic marker to ploidy testing in brown trout (Salmo trutta L.) triploidised by heat shock

A phosphoglucose isomerase (PGI) variant, of brown trout (Salmo trutta L.), expressed in adipose fin tissue, was incorporated into experimental batches through selective crossing of brood-stock having the PGI-3 (110) marker gene. PGI-3 (110) homozygous females were crossed with PGI-3 (100) homozygous males to yield all PGI-3 (110/100) progeny. These were subject to heat shock for 10 min at 28°C, commencing 10 min after insemination. Electrophoretic examination of fry indicated that diploids and triploids were separable on the basis of PGI-3 banding patterns, having staining ratios of 1:2:1 and 4:4:1, respectively. This confirmed the retention of an extra maternal PGI-3 (110) gene in triploid individuals. Potential applications of this marker in triploid studies in brown trout are discussed.     

Minimizing instrumentation requirement for estimating crop water stress index and transpiration of maize

Research was conducted in northern Colorado in 2011 to estimate the crop water stress index (CWSI) and actual transpiration (T _a) of maize under a range of irrigation regimes. The main goal was to obtain these parameters with minimum instrumentation and measurements. The results confirmed that empirical baselines required for CWSI calculation are transferable within regions with similar climatic conditions, eliminating the need to develop them for each irrigation scheme. This means that maize CWSI can be determined using only two instruments: an infrared thermometer and an air temperature/relative humidity sensor. Reference evapotranspiration data obtained from a modified atmometer were similar to those estimated at a standard weather station, suggesting that maize T _a can be calculated based on CWSI and by adding one additional instrument: a modified atmometer. Estimated CWSI during four hourly periods centered on solar noon was largest during the 2 h after solar noon. Hence, this time window is recommended for once-a-day data acquisition if the goal is to capture maximum stress level. Maize T _a based on CWSI during the first hourly period (10:00–11:00) was closest to T _a estimates from a widely used crop coefficient model. Thus, this time window is recommended if the goal is to monitor maize water use. Average CWSI over the 2 h after solar noon and during the study period (early August to late September, 2011) was 0.19, 0.57, and 0.20 for plots under full, low-frequency deficit, and high-frequency deficit irrigation regimes, respectively. During the same period (50 days), total maize T _a based on the 10:00–11:00 CWSI was 218, 141, and 208 mm for the same treatments, respectively. These values were within 3 % of the results of the crop coefficient approach.