Hydrology influences breeding time in the white-throated dipper

While nitrogen and carbon stable isotope values can reflect ecological segregation, prey choice and spatial distribution in seabirds, the interpretation of bulk stable isotope values is frequently hampered by a lack of isotopic baseline data. In this study, we used compound-specific isotope analyses of amino acids (CSIA-AA) to overcome this constraint and to study interspecific differences, seasonal and historical changes in trophic positions of five seabird species, three penguins and two petrels, from a sub-Antarctic seabird community. CSIA-AA allowed comparing trophic positions of seabirds with temperate and polar distributions. Gentoo and Magellanic penguins had the highest trophic positions during the breeding season (3.7 and 3.9), but decreased these (2.9 and 3.3) during the feed-up for moult. Intra-specific differences were also detected in Thin-billed prions, where carbon isotope values clearly separated individuals with polar and temperate distributions, both in the breeding and interbreeding periods. Thin-billed prions that foraged in polar waters had lower trophic positions (3.2) than conspecifics foraging in temperate waters (3.8). We further investigated historical changes by comparing museum samples with samples collected recently. Our pilot study suggests that Rockhopper penguins, Magellanic penguins and Thin-billed prions with temperate non-breeding distributions had retained their trophic levels over a 90–100 year period, while Gentoo penguins and Thin-billed prions with polar non-breeding distributions had decreased trophic levels compared to historical samples. In contrast, Wilson’s storm-petrels had slightly increased trophic levels compared to samples taken in 1924–1930. We applied compound-specific stable isotope analyses across a range of contexts, from intra-specific comparisons between stages of the breeding cycle to inter-specific seabird community analysis that would not have been possible using bulk stable isotope analyses alone due to differences in isotopic baselines.     

Thermal performance curves based on field movements reveal context-dependence of thermal traits in a desert ectotherm

Landscape Ecology - Thermal traits likely mediate organismal responses to changing thermal environments. As temperatures increase, predicting species responses will depend on understanding how...     

Die Ebersberger Waldordnung aus dem 13. Jahrhundert

Ohne Zusammenfassung     

Fluoreszenzmikroskopischer Nachweis von DDT und seinen Mitteln

Ohne Zusammenfassung     

Die Nachhaltigkeit von Düngungssystemen — Dargestellt am seehausener Düngungs‐Kombinationsversuch

Der 1967 in Seehausen auf sandigem Lehm angelegte Düngungs‐Kombinationsversuch dient der Analyse von Langzeitwirkungen gestaffelter Stallmist‐ und Mineral‐N‐Gaben (0,50,100,150 kg N ha^?1 a^?1) auf Pflanzen, Boden und Umwelt. Anhand von Meß‐, Bilanz‐ und Simulationswerten wird die Nachhaltigkeit dieser Düngungsvarianten bewertet.

Organisch‐mineralische Düngung führte zu Maximalerträgen von über 12t TM ha^?1 a^?1 und N‐Entzügen bis 200 kg ha^?1 a^?1. Der N‐Entzug der ungedüngten Variante betrug in den letzten Jahren noch etwa 75 kg ha^?1a^?1 gegenüber 100 kg ha^?1a^?1 zu Versuchsbeginn.

Die Entwicklung der Boden‐N_t‐Gehalte konnte mit e‐Funktionen beschrieben werden. Mineral‐N allein genügte nicht zum Erhalt der N_t‐Ausgangsvorräte, hierfür waren 55 bis 85 kg Stalldung‐N ha^?1 a^?1 notwendig. Die N_t‐ und C_t‐Gehalte korrelierten mit zahlreichen Bodenparametern. Hohe Humusgehalte forderten die biologische Aktivität.

Die N‐Verluste betrugen <10kg ha^?1 a^?1 (ungedüngt) bis 120 kg ha^?1a^?1 (höchstgedüngte Variante). Das N‐Verlustpotential lag bei Stallmistanwendung etwas niedriger als bei gleicher N‐Zufuhr in Mineralform. Je nach Stallmist‐Stufe waren 62 bis 104 kg Mineral‐N ha^?1 a^?1 erforderlich, um den Energieeinsatz je Produkteinheit zu minimieren.

Kombinierte Anwendung organischer und mineralischer Dünger (je 100 kg N ha^?1 a^?1) führte zu höchsten ökonomischen Leistungen, günstigen Bodeneigenschaften und tolerierbaren Umweltwirkungen. Zieht man alle verwendeten Nachhaltigkeitskriterien in Betracht, ist dieses Düngungssystem den anderen überlegen.     

Freezing of stallion semen with addition of glycine betaine

The effect of addition of glycine betaine to a lactose-EDTA freezing medium on the post-thaw motility of stallion semen was determined. The first three semen-rich fractions of nine stallions were collected with an open-end Krakow artificial vagina on consecutive weekdays. Semen was frozen using the Hannover method with freezing media containing glycine betaine in various concentrations from 0 to 5%. After thawing, sperm motility was analysed both by a light microscope and by a Hamilton-Thorn Motility Analyser. Total and progressive post-thaw motilities of semen containing 0.25-3% glycine betaine did not differ significantly from the total and progressive post-thaw motilities of semen frozen without glycine betaine. The total and progressive post-thaw motilities of semen containing 4 or 5% glycine betaine were significantly lower (P < 0.001) than those of semen without glycine betaine. In conclusion, glycine betaine did not show any beneficial effect on the post-thaw motility of stallion semen when semen was frozen using the Hannover method.