Ontogenetic and spatial variations in brown trout habitat selection

Ayllón D, Almodóvar A, Nicola GG, Elvira B. Ontogenetic and spatial variations in brown trout habitat selection.
Ecology of Freshwater Fish 2010: 19: 420–432. © 2010 John Wiley & Sons A/S Abstract – Habitat quality and quantity determine many biological processes and traits that directly affect the population dynamics of stream fishes. Understanding how habitat selection is adjusted to different ecological conditions is essential to improve predictive modelling of population dynamics. We describe brown trout Salmo trutta summer habitat selection patterns through univariate and multivariate habitat selection functions across defined river reach typologies. We sampled 44 sites and performed a principal component analysis that defined eight reach types differing in both local site and catchment‐scale physical features. We observed ontogenetic changes in habitat selection, as trout preferred deeper and slower flowing water as they increased in size. Likewise, selectivity for different types of structural habitat elements changed through ontogeny. Both patterns were consistent across reach types. Moreover, we detected spatial variations in habitat selection patterns within age‐classes among different reach types. Our results indicate that brown trout is a habitat generalist and suggest that spatial variations in habitat selection patterns are driven by physical and environmental factors operating at multiple spatial scales.     

Zur Wirkung von Follikelflüssigkeit auf die Befruchtung in vitro gereifter Oozyten des Rindes

Inhalt Follikelflüssigkeit aus Follikeln des Rindes am Tag des Östrus gewonnen, wurde als Serumanalogon zum Kultivierungsmedium TCM 199 zugesetzt. Die Supplementierung des TCM mit 20%östrischer Follikelflüssigkeit (ÖFF) in der Reifungsphase und während der Zygotenkultivierung erbrachte 6–7 Tage post inseminationem einen Anteil an Morulae und Blastozysten von 41,7% (30,8–47,8%). Eine Reduzierung des Anteils ÖFF auf 10% zog einen Abfall transfertauglicher Rinderembryonen auf 9,2% (2,6–16,9%) nach sich. In einer Kurzzeitkultivierung von bis zu 90 h post inseminationem wurden außerdem verschiedene Serumanaloga, im Anteil von 10%, wie fetales Kälberserum (FKS), ÖFF und Follikelflüssigkeit (NÖFF) aus nicht östrischen Follikeln (≥ 10mm Durchmesser) auf ihre Wirksamkeit während verschiedener In-vitro-Phasen verglichen. Von den drei getesteten Seren erwies sich die ÖFF als der wirksamste Zusatz mit 19,9% morphologisch intakten 8- bis 16-Zeller. Das Ergebnis scheint unabhängig davon, ob die Applikation kontinuierlich während aller In-vitro-Phasen oder nur in der Reifungsphase erfolgte. Eine Schlüsselposition der Oozy tenreifung für die In-vitro-Fertilisation wird besonders deutlich. Contents: Influence of follicular fluid on fertilization of in vitro matured bovine oocytes Follicular fluid obtained from bovine follicles on the day of estrus was added to TCM 199 culture medium as a serum analogue. TCM supplementation with 20% estric follicular fluid (EFF) during maturation and zygote cultivation produced a morulae and blastozyst yield of 41,7% (30,8–47,8%) 6–7 days after insemination. Reduction of the EFF fraction to 10% reduced the yield of transferable bovine embryos to 9,2% (2,6–16,9%). In a short term cultivation experiment lasting up to 90 h after insemination, the effects of 10% supplementation with different serum analogues fetal calf serum (FCS), EFF and follicular fluid (NEFF) fiom non-estric follicles (≥10mm diameter) during various in vitro phases were compared. EFF with a yield of 19,9% morphologically intact 8 to 16 cell stages proved to be the most effective of the three sera. This yield is not apparently affected by whether the serum is applied continuously during all phases of in vitro development or only during the maturation phase. The oocyte maturation phase is obviously the key phase for successful in vitro fertilization.     

Translocation of soils to stimulate climate change: CO2 emissions and modifications to soil organic matter

The effect of climate change on CO₂ emissions was studied on undisturbed soil monoliths (40‐cm diameter, 25‐cm high), which were translocated to warmer zones than their place of origin. Thirty‐two months after the translocation, a climatic factor deduced from the moisture content of the soil and from the effective mean temperature (temperatures in excess of 5°C) revealed that translocation increased the potential of the climate to enhance the biological processes by between 73% and 26% compared with what the soil would support in its place of origin. At the end of the study, the transported soils had lost a large proportion of both total carbon and nitrogen (between 20 and 45%). During the experiment, the CO₂ emissions from the soils, measured under field conditions, were quite variable, but were usually greater than from soils in situ. The variation in labile C in the soil throughout the experiment was calculated from a first‐order kinetic equation for organic matter decay. The relative CO₂ emissions, expressed in terms of the labile carbon fraction in the soils, were clearly greater in those translocated soils that underwent the most intensive climate change, which indicates that the variations in emissions over time are basically a function of the size of the labile organic matter pool.     

Foliar application of systemic insecticides disrupts feeding behavior of the whitefly Bemisia tabaci MEAM1 and the transmission of tomato chlorosis virus in potato plants

Journal of Pest Science - The whiteflies of the Bemisia tabaci (Genn.) complex (Hemiptera: Aleyrodidae) are serious agricultural pests that cause severe losses to vegetable, ornamental and fiber...     

Applications of Trichoderma formulations in crop protection

The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic cap…     

An overview of forest loss and restoration in the Brazilian Amazon

New Forests - Forest restoration is a strategy to reverse forest loss and degradation. We overviewed deforestation in the period 1975–2018 in the Brazilian Amazon and the projects,...     

日粮中维生素A含量影响猪肉中脂肪酸的组成

本试验的目的是为了研究日粮中维生素A的含量对猪肉中脂肪酸组成的影响。采用128只杜洛克×（大白×长白）阉割公猪,随机分组,每个圈里4只猪。对照组16个圈中猪日粮的维生素A为基础水平（7500IU／kg）,处理组16个圈中猪日粮的维生素A含量丰富（100,000IU／kg）。在平均体重达125．9kg时进行屠宰。结果未发现维生素A水平对生长性能、胴体性状及肌内脂肪的影响。     

Serotypes,phage types and virulence genes of shiga-producing Escherichia coli isolated from sheep in Spain

PROBLEM ADDRESSED: Shiga toxin-producing Escherichia coli (STEC), have emerged as food poisoning pathogens which can cause severe diseases in humans. OBJECTIVE: The aim of this study was to determinate the serotypes and virulence genes of STEC strains isolated from sheep in Spain, with the purpose of determining whether sheep represent a potential source of STEC pathogenic for humans. METHODS AND APPROACH: Faecal swabs obtained from 697 healthy lambs on 35 flocks in Spain during the years 2000 and 2001 were examined for STEC using phenotypic (Vero cells) and genotypic (PCR) methods. RESULTS: STEC O157:H7 strains were isolated from seven (1%) animals in six flocks, whereas non-O157 STEC strains were isolated from 246 (35%) lambs in 33 flocks. A total of 253 ovine STEC strains were identified in this study. PCR showed that 110 (43%) strains carried stx(1) genes, 10 (4%) possessed stx(2) genes and 133 (53%) both stx(1) and stx(2). Enterohaemolysin (ehxA) and intimin (eae) virulence genes were detected in 120 (47%) and in 9 (4%) of the STEC strains. STEC strains belonged to 22 O serogroups and 44 O:H serotypes. However, 70% were of one of these six serogroups (O6, O91, O117, O128, O146, O166) and 71% belonged to only nine serotypes (O6:H10, O76:H19, O91:H-, O117:H-, O128:H-, O128:H2, O146:H21, O157:H7, O166:H28). A total of 10 new O:H serotypes not previously reported in STEC strains were found in this study. Seven strains of serotype O157:H7 possessed intimin type gamma1, and two strains of serotype O156:H- had the new intimin zeta. STEC O157:H7 strains were phage types 54 (four strains), 34 (two strains) and 14 (one strain). CONCLUSIONS: This study confirms that healthy sheep are a major reservoir of STEC pathogenic for humans. However, because the eae gene is present only in a very small proportion of ovine non-O157 STEC, most ovine strains may be less pathogenic.     

Impacting Librarianship and Veterinary Medicine: History of the Veterinary Medical Libraries Section of the Medical Library Association from 1974 to 2014

This article discusses the Veterinary Medical Libraries Section (VMLS) of the Medical Library Association (MLA), its impacts on both librarianship and veterinary medicine during its 40-year history, how it achieved those impacts, relationships, selected projects, and organizational changes through the years. A listing of publications about veterinary librarianship and VMLS products is available on the VMLS website (Veterinary Medical Libraries Section, 2014).