Water availability affects nectar sugar production and insect visitation of the cup plant Silphium perfoliatum L. (Asteraceae)

The perennial cup plant (Silphium perfoliatum L.) is considered as an alternative feedstock to maize for biogas plants. Due to its ecological advantages of an extensive management and function as food resource for pollinators, it can be grown in Ecological Focus Areas (EFAs) since 2018. However, studies at the Julius Kühn-Institute in Braunschweig (Germany) showed that the assumed advantage of the cup plant of a high drought tolerance could not be confirmed regarding aspects of crop production and yield. We complemented this experiment by assessing how different soil moisture conditions affect the production of floral resources and insect visitation. In 2014, we sampled three irrigated and three rainfed plots of the cup plant. We quantified the nectar volume and sugar mass per inflorescence, the number of inflorescences per plant and calculated the total nectar sugar production. We further counted insect visitation on the inflorescences. Due to reduced numbers of inflorescences per plant and an earlier harvest, the estimated nectar sugar production was 58 kg/ha regarding irrigated and 20 kg/ha regarding rainfed plots. Honeybee visitation per inflorescence was about twice as high in the irrigated plots. Furthermore, the early harvest is a disadvantage for wild pollinators with a late activity period.     

Association between floor type and behaviour, skin lesions, and claw dimensions in group-housed fattening bulls

Rubber mats covering concrete slatted flooring are a developing market in dairy barns but remain rare in beef cattle facilities. The aim of this study was to investigate the effects of covering slatted concrete floor with perforated rubber mats on behaviour and occurrence of skin and claw lesions in fattening bulls. The groups of six bulls each with a total average age of 9.8 months were kept over 1 year on either slatted concrete (CONCRETE PEN) or on slatted concrete covered completely (RUBBER PEN) or partially (CHOICE PEN) with perforated rubber mats. Every quarter-year, behaviour (preference of flooring, lying, aggression, mounting) was recorded. In two-weekly intervals the incidence of skin lesions was examined. At 12 and 18 months of age the rising time of the bulls was measured. At the beginning of the study and after slaughter claw dimensions were recorded. Bulls in the CHOICE PEN preferred (P<0.01) the rubber coated area throughout the experiment. Animals in the RUBBER and the CHOICE PENS showed more lying periods (P<0.01) and had a lesser incidence of skin lesions (P<0.01) compared to bulls in the CONCRETE PEN. Bulls in the CHOICE PEN needed less time for rising (2.7+/-0.3s) than bulls in the CONCRETE PEN (4.4+/-0.5s, P<0.01). Net claw growth differed significantly between all pens (RUBBER>CHOICE>CONCRETE; P<0.05). In conclusion, the results of this study indicate that rubber coated slatted flooring has a positive influence on the housing conditions of beef cattle.     

The Prince Edward Islands: A sanctuary for seabirds in the Southern Ocean

This paper reviews the breeding distribution and numerical status of selected species of seabirds at 23 oceanic island groups in the Southern Ocean (between latitudes 35 and 70°S), based on census data and population estimates which have become available through increased scientific endeavour in the region during the last 15 years or so. The paper focuses on the avifauna of the Prince Edward islands, in the southern Indian Ocean, and points to the importance of these islands as a breeding station and sanctuary for seabirds. Only one oceanic island group, the Crozets, contains more species of breeding seabirds than the Prince Edward islands. Substantial segements (about 10% and greater) of the world breeding populations of the king and macaroni penguins, and the wandering, grey-headed, yellow-nosed and sooty albatrosses are based at the Prince Edward group. We recommend that Prince Edward Island (sensu stricto) should be a wilderness area, and that development at Marion Island should be kept to an absolute minimum.     

Conservation of the jackass penguin (Spheniscus demersus (L.))

The jackass penguin Spheniscus demersus (L.) is confined to the coastal waters of southern Africa, and breeds on 18 islands predominantly within the region of the cold, nutrient rich Benguella current. Since the early 1900s the species' population has declined in numbers of unknown magnitude. The decline appears to be continuing, although the absence of reliable census data precludes an accurate measurement of the rate of change. The initial fall in numbers was undoubtedly due to severe disturbance of nesting birds and excessive commercial exploitation of eggs. The average annual egg crop for the period 1900-30 exceeded 450,000 eggs from Dassen Island alone. Egg collection has been suspended temporarily, but the species now appears to be threatened by oil pollution, and by competition with a pelagic shoal fish industry. Threats to breeding colonies are posed by harbour developments. These factors are discussed and evaluated. South African marine organisms are considered officially to be an economic resource and are heavily exploited. Legislation governing the control of this resource is the concern of the Ministry for Economic Affairs. There is no provision for any government body to investigate the status and biology of economically insignificant, but yet integral, components of the marine ecosystem. The major priority of conservations is to safeguard the jackass penguin population at its present level. This includes proclamation of several offshore islands and their surroundings as national nature reserves. We consider current efforts to rescue, clean and rehabilitate oiled seabirds as contributing little to conservation in real terms, even though the activity has an important humanitarian and educational function. Research priorities include a comprehensive census of the jackass penguin and other seabird populations in southern Africa; a study of mortality and recruitment, with particular attention to factors affecting the rates of these processes; a study of the dynamics of the penguin/prey interaction, with special reference to the possible effects of competition with the pelagic fishing industry; an evaluation of the degree of disturbance that nesting penguins can tolerate; an investigation into the temporal and spatial patterns of oil pollution incidents, oil slick occurrence and movement, and the development of methods of keeping birds away from oil slicks; and, lastly, an evaluation of the efficacy of rehabilitating oiled penguins as a contribution to maintaining or increasing the current jackass penguin population. The responsibility for these projects rests with the South African government.     

Use of a population model to assess the impact of longline fishing on wandering albatross Diomedea exulans populations

An age-structured model of a wandering albatross Diomedea exulans population is developed to stimulate population trends over time, using demographic parameters from the population at Possession Island, Crozets, during 1968–1986. The simulation results portray a population decreasing at a rate of 2·29% per year, which concurs with global population trends. Sensitivity analyses of model parameters indicate that both adult and juvenile mortality are contributing to the decrease. Wandering albatross mortality is presumed to have increased as a result of deaths caused by longline fishing vessels; such deaths are likely to be relatively more frequent among young, naive birds. The model is used to investigate the potential impacts of new longline fisheries such as that for Patagonian toothfish Dissostichus eleginoides in Antarctica. Assuming longline fishing operations affect juveniles more than adults, there is a time lag of 5–10 years before further decreases in population numbers are reflected in the breeding population. Also, because wandering albatrosses are long-lived, population growth rates take approximately 30–50 years to stabilize after a perturbation. Consequently, caution must be exercised when interpreting population trends; short-term (<20 year) estimates may not provide good indications of long-term trends.     

Zur Systematik vonAvena sativa L. und zur Beurteilung vonAvena nuda Höj

Zusammenfassung Der NameAvena nuda Höjer ist sowohl zur Kennzeichnung der diploiden als auch der hexaploiden Nackthafer verwendet worden. Der nomenklatorische Typus vonA. sativa L. wird diskutiert. Auf der Grundlage der Gliederungsübersichten von Alefeld, Körnicke, Ascherson und Graebner, Malzev, Mordvinkina und Stanton wird ein System vorgeschlagen, in dem zwei Convarietäten und 19 Varietäten unterschieden werden.

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Taxonomy ofAvena sativa L. and interpretation ofAvena nuda Höjer

Summary The nameAvena nuda Höjer was used for characterizing as the diploid as the hexaploid nacked oats. The nomenclatorical type ofA. sativa L. is discussed. On the basis of the divisions given by Alefeld, Körnicke, Ascherson and Graebner, Malzev, Mordvinkina and Stanton a system is proposed differentiating two convarieties and 19 varieties.

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Avena sativa L. Avena nuda Höj

Avena nuda Höjer , , . A. sativa L. Ha , , , , , , 2 19 .

     

Infragenerische Taxa der GattungSolanum L.

Zusammenfassung DieSolana sind eine der größten Gattungen des Pflanzenreiches. Zahlreiche infragenerische Taxa sind beschrieben worden, doch fehlte bisher eine Grundlage zur Orientierung in der Mannigfaltigkeit. Für die Untergattungen und Sektionen wird ein Bestimmungsschlüssel vorgeschlagen.Da in der Vergangenheit mehrere Sektionen als selbständige Gattungen abgetrennt wurden, ist zu prüfen, ob die beiden traditionell unterschiedenen Hauptgruppen als Abstammungsgemeinschaften in der Rangstufe einer Gattung bewertet werden können. Es gibt aber einige Sektionen, die eine Zwischenstellung einnehmen (sect.Brevantherum, Aculeigerum, Acanthophora, Somalanum, Anisantherum, Irenosolanum, Lepidotum) und gegen einen diphyletischen Verlauf der Evolution sprechen. Die Verwandtschaftsverhältnisse der Sektionen werden diskutiert, um gleichwertige infragenerische Taxa oberhalb dieser Rangstufe zu erfassen.Einige bislang übersehene Sektionsnamen mußten aus Prioritätsgründen eingesetzt werden (sect.Geminatum, Torvum, Potatoe, Holophyllum, Cryptocarpum, Acanthophora).

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Infrageneric taxa of the genusSolanum

Summary TheSolana are one of the largest genera in the plant kingdom. Numerous infrageneric taxa had been described, but till now no basis exist for orientation in the diversity. For the subgenera and sections a key for determination is proposed. Because in the past time several sections have been seperated as own genera examinations are necessary for judging both the traditional distinguished maingroups as taxa in the rank of a genus. But there are some sections with an intermediate position (sect.Brevantherum, Aculeigerum, Acanthophora, Somalanum, Anisantherum, Irenosolanum, Lepidotum), documenting that the course of evolution can not be interpreted as diphyletically. The relations between the sections are discussed to outline equal infrageneric taxa above this rank.Some till now not used names of sections had to be introduced from reasons of priority (sect.Geminatum, Torvum, Potatoe, Holophyllum, Cryptocarpum, Acanthophora).

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Solanum L.

Solanum — . ¶rt; , ¶rt; . . , , , , . (sect.Brevantherum, Aculeigerum, Acanthophora, Somalanum, Anisantherum, Irenosolanum, Lepidotum) , ¶rt;. , ¶rt; ¶rt; . (sect.Geminatum, Torvum, Potatoe, Holophyllum, Cryptocarpum, Acanthophora).

     

On the cause of the 1930s Dust Bowl

During the 1930s, the United States experienced one of the most devastating droughts of the past century. The drought affected almost two-thirds of the country and parts of Mexico and Canada and was infamous for the numerous dust storms that occurred in the southern Great Plains. In this study, we present model results that indicate that the drought was caused by anomalous tropical sea surface temperatures during that decade and that interactions between the atmosphere and the land surface increased its severity. We also contrast the 1930s drought with other North American droughts of the 20th century.     

Redox regulation of germline and vulval development in Caenorhabditis elegans

In vitro studies have indicated that reactive oxygen species (ROS) and the oxidation of signaling molecules are important mediators of signal transduction. We have identified two pathways by which the altered redox chemistry of the clk-1 mutants of Caenorhabditis elegans acts in vivo on germline development. One pathway depends on the oxidation of an analog of vertebrate low density lipoprotein (LDL) and acts on the germline through the Ack-related tyrosine kinase (ARK-1) kinase and inositol trisphosphate (IP3) signaling. The other pathway is the oncogenic ras signaling pathway, whose action on germline as well as vulval development appears to be modulated by cytoplasmic ROS.