Über lästige Vögel und Säuger als Kulturfolger an Müllkippen und Mö glichkeiten zu ihrer biologischen Bekämpfung

Zusammenfassung Müllkippen begünstigen lästige Kulturfolger, vor allem Krähen(Corvus c. corone, C. frugilegius) und die Wanderratte(Rattus norvegicus). Dabei ist die Lage und Umgebung für das Auftreten der Krähen von großer Bedeutung. Sie bevorzugen offene Landschaften.Wichtigste Feinde der Wanderratte an solchen Plätzen sind das Hermelin(Mustela erminea) und der Iltis(Putorius putorius). Sie verdienen Schutz und Förderung. Es werden einige Möglichkeiten zur biologischen Bekämpfung der Ratten und Krähen aufgezeigt.Summary Observations were made on 19 rubbish tips in the surrounding of Munich which revealed the fact that these areas are favourable for some injurious birds and mammals, i. e., such as crows(Corvus c. corone, C. frugilegius) and rats(Rattus norvegicus). The geographical distribution and the composition of the environment are very important aspects for the existance of the crows in mass number, because these birds prefer open lands and avoid larger forests.General survey indicated that the most important natural enemies of the rats are the white stoat(Mustela erminea) and the polecat(Putorius putorius). These rabacious mammals were observed to enter through the underground rat-tunnels and were able to drive them out.The mustelids should be protected and encouraged to live in rubbish tips. Some suggestions to apply the biological control approch against crows and rats were discussed.     

Leichthölzer und Tonnenstämme in Schwarzwassergebieten und Dornbuschwäldern des tropischen Südamerika

European Journal of Forest Research -     

Derivation of stem taper from the pipe theory in a carbon balance framework

A dynamic tree growth model is described. The model derives the development of stem taper and vertical distribution of branch basal area from the pipe model, assuming that reuse of active pipes is regulated by foliage dynamics in a vertically explicit crown with a foliage distribution of constant shape. Based on empirical findings, the pipe model was modified slightly to allow the foliage/sapwood ratio to vary as a function of distance from the treetop. Growth was derived from carbon balance in a stand of different size trees that may shade each other. The model was applied to old and middle-aged trees growing in dense and sparse stands of Scots pine for which stand-level measurements are available as a chronosequence, but individual trees have been measured only once. Measured trees were compared with corresponding simulated trees for stem taper and vertical distribution of branch basal area. The results indicated that the pipe model assumptions, combined with a model of tree growth, are capable of producing realistic predictions of the vertical distribution of stem and branch diameter in trees of different sizes in the stand. A comparison of the results with a simple form of the uniform stress theory showed good agreement between the two models. However, a significant difference was found between the measured relative contribution of heartwood to total stem diameter and the predicted share of disused pipes in the stem. A possible explanation for this discrepancy is that the transition from sapwood to heartwood is gradual rather than abrupt as assumed in the model. A modification of the pipe model to incorporate a gradual transition is outlined.     

Entwicklung einiger Nistkastenbewohner in ostbayerischen Waldgebieten Teil II: Säuger

From 1950 until 1987 up to 3,350 nest-boxes were checked each year in woodland of Eastern Bavaria. Among the mammals bats (Myotis daubentoni and other species), dormice (Muscardinus avellanarius, Glis glis andEliomys quercinus) and mice (Apodemus spp.) were observed. The distribution of the dominant species is mapped (Figs. 1, 3) and the annual percentage of occupied boxes by different groups and species is shown in diagrams (Figs. 2, 4, 5). The quote of nest-boxes inhabited by small mammals increased since 1980. Several factors influencing the occurrence of mammals in nest-boxes such as adaption, competition, population density and climatic conditions are discussed.

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Mit 6 Abbildungen     

An artificial diet for shrews (Soricidae)

The common shrew (Sorex araneus L.) and the pygmy shrew (S. minutus L.) could be raised for several months in captivity using the tupaii food Altromin 8010^®. The artificial diet was well accepted and the animals increased in weight.     

Wachstum und Vermehrung der Erdmans(Microtus agrestis L.) auf Forstkulturen

Growth and reproduction of the Field Vole (Microtus agrestis L.) in forest plantations The growth of the Field Vole was persecuted by means of the capture mark and recapture method in the years 1971–75. Investigations were made about the number of embryoes, the condition of the gonads and the blood glucose content of specimens which were trapped in comparable areas nearby and killed immediately after capture.In each year a peak of number of embryoes, percentage of pregnant females and a short distance between pregnancy was observed in May and June. At this time also males reached a high index weight of the testes and young males with juvenile coat were sexually mature. The growth of the testes began at the end of February and was followed by a rapid increase of body weight in the spring. In the midsummer a fast decline in body weight was observed and the havier males disappeared. At this time the blood glucose content was at a minimum about 25–90 mg./ 100 ml. blood. The highest level over 250mg./100ml. was observed in winter. The high energy requirement for growth and reproduction of the voles in early spring can cause damages in forest plantations. At this time trees with freshly gnawed bark were observed.     

Nitrogen forms in bark, wood and foliage of nitrogen-fertilized Pinus sylvestris

Cycling of soluble non-protein N compounds is thought to be indicative of the N-nutritional status of trees. We determined the major N forms in bark, wood and foliage and estimated the dependence of prevalent N forms on N availability in Pinus sylvestris L. trees from northern Sweden. Trees subjected to severe N limitation and trees that had been fertilized with an average 64 kg N ha(-1) year(-1) for 25 years were analyzed. Bark and wood samples were collected by tangentially cryo-sectioning the trunk into 30-microm thick sections, from the bark to the functional xylem. Soluble amino compounds were extracted from the sections for analysis. Sap samples from twigs were obtained by centrifugation, and bark samples from twigs were obtained by tissue extraction. In both needles and bark, arginine dominated the amino-N pool. Because arginine concentrations in needles increased with N fertilization, arginine dominance of the amino-N pool in needles was higher in N-fertilized trees than in control trees. In bark, N fertilization resulted in a large increase in glutamine concentration, so that glutamine accounted for a larger proportion of the amino-N pool in bark in N-fertilized trees than in control trees. Glutamine dominated the amino-N pool in wood of control trees. Nitrogen fertilization resulted in an increased proportion of arginine in the wood amino-N pool. We conclude that the composition of the amino-N pools in bark, wood and foliage is highly sensitive to N supply. The composition of the amino-N pools can contribute to the regulation of tree N-nutritional status, which is mediated by shoot to root signalling by long-distance transport of amino compounds.     

Acclimation of photosynthetic capacity in Scots pine to the annual cycle of temperature

Coniferous trees growing in the boreal and temperate zones have a clear annual cycle of photosynthetic activity. A recent study demonstrated that the seasonal variation in photosynthetic capacity of Scots pine (Pinus sylvestris L.) could be attributed mainly to the light response curve of photosynthesis. The magnitude of the light response curve varied over the season while its shape remained constant, indicating that the two physiological parameters quantifying the curve-the quantum yield per unit internal carbon dioxide concentration and the corresponding light-saturated rate-remained proportional to each other. We now show, through modeling studies, that the quantum yield (and hence the light-saturated rate) is related to the annual cycle of temperature through a delayed dynamic response. The proposed model was tested by comparing model results with intensive measurements of photosynthesis and driving variables made from April to October in three shoots of Scots pine growing near the northern timberline. Photosynthetic capacity showed considerable acclimation during the growing season. A single model describing photosynthetic capacity as a reversible, first-order delay process driven by temperature explained most of the variation in photosynthetic capacity during the year. The proposed model is simpler but no less accurate than previous models of the annual cycle of photosynthetic capacity.     

Predicting spring phenology and frost damage risk of Betula spp. under climatic warming: a comparison of two models

Timing of bud burst and frost damage risk for leaves of Betula spp. in response to climatic warming in Finland was examined with two models. In the first model, ontogenetic development in spring was triggered by an accumulation of chilling temperatures. The second model assumed an additional signal from the light climate. The two models gave radically different estimates of frost damage risk in response to climate warming. The chilling-triggered model forecast a significant and increasing risk with increased warming, whereas the light-climate-triggered model predicted little or no risk. The chilling-triggered model is widely applied in phenological research; however, there is increasing experimental evidence that light conditions play a role in the timing of spring phenology. Although it is not clear if the light response mechanisms are appropriately represented in our model, the results imply that reliance on a light signal for spring development would afford a degree of protection against possible frost damage under climate warming that would not be present if chilling were the sole determinant. Further experimental tests are required to ascertain the light-related mechanisms controlling phenological timing, so that credible model extrapolations can be undertaken.