Parallelism in thermal growth response in otoliths and scales of brown trout (Salmo trutta L.) from alpine lakes independent of genetic background

Low density in natural populations of salmonids has predominantly been managed by stocking of non‐native conspecifics. Due partly to domestication, introduced non‐native fish may be maladapted under natural conditions. Interbreeding between introduced and wild individuals may therefore impair local adaptation and potentially population viability. Brown trout (Salmo trutta L.) from three headwaters (with stocked fish) and three interconnected lakes (with native fish) on the Hardangervidda mountain plateau, southern Norway, were tested for differences in thermal effects on scale and otolith growth. Otolith and scale annuli widths from immature brown trout showed positive correlation with mean annual summer temperature for all six sampled populations. In mature individuals, a similar positive thermal correlation was evident for the otoliths only. Interannuli width measurements from scales indicate a halt in somatic growth for brown trout in this alpine environment when reaching ages between 7 and 9 winters, coinciding with age at maturity. Our study indicates that otolith growth follows summer temperature even when individuals do not respond with somatic growth in these populations and that introduced brown trout and introgressed populations have similar thermal growth responses. Due to the continued otolith growth after stagnation in somatic growth and the impact of fluctuations in summer temperature, the utilisation of otolith annuli widths for back calculation of length at age should be treated with caution.     

The effect of induced autotetraploidy on resistance to clover rot (Sclerotinia trifoliorum erikss.) in red clover

In infection experiments with clover rot (Sclerotinia trifoliorum Erikss.) on 9 pairs of diploid and corresponding autotetraploid families arisen from chimaera plants the tetraploid families proved to be more resistant than their corresponding diploid families. Significant interaction between family pairs and ploidy level was demonstrated and this is an indication that there may be differences between different genotypes with respect to the effect of autotetraploidy on resistance to clover rot in red clover.

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Samenvatting Bij kunstmatige infectie met klaverkanker van 9 paren (uit chimaere planten van rode klaver afkomstige) diploide en daarmede corresponderende autotetraploide families bleken de tetraploide families grotere resistentie te vertonen dan de daarmede corresponderende diploide families.Uit een vergelijking van de families bleek dat er verschillen in invloed van de autotetraploidie op de resistentie tegen klaverkanker zijn.

     

Characteristics and conflicts in Norwegian agriculture

This article raises the issue of the extent to which a single nation can develop a “national agricultural policy,” pursuing internal goals in agrarian development, goals that vary significantly from those of other industrialized countries. What are the conflicts arising from such a policy and how do these conflicts interfere with the general agricultural crisis of these countries? The Norwegian case is explored as an example of a blend of social-democratic and center-populist agricultural policies. The decision in 1975 by the Norwegian Parliament to establish the income level of farmers at the same level as workers is seen as an experiment. As agricultural policy, this new departure represented a deviation from the earlier policies of rationalization. The Social Democrats developed their new position as a result of internal and external pressure. A series of reforms financed by the new state incomes from oil production were undertaken, of which income equalization and a farm relief service were the most important. Most Norwegian farmers speak of the reform years as “the good years of escalation.” Equity was reached in 1982, but nevertheless several problems emerged: 1) the escalation of subsidized incomes led to overproduction and decreasing incomes from the market (after 1982), 2) the large budgetary transfers to agriculture caused a legitimation crisis, fueling the constituency of the right-wing Progress Party, 3) the large subsidies to agriculture contributed to the fiscal crisis of the state, 4) the problems mentioned above, contributed to the general crisis of the Norwegian Social Democracy which finds itself with dwindling support. The likely outcome of the present Norwegian farm crisis is the implementation of an agricultural policy that will protect the most vulnerable sector and open the more competitive sector to market forces.     

European restructuring and changing agricultural policies. Rural self-identity and modes of life in late modernity

The main idea of this article is to present various perspectives in order to analyze the recent crisis concerning the agriculture-based rural societies in the developed capitalist communities. In all of these countries there is a production crisis, resulting in too much food. But this is also an ideological crisis, because the consumer thinks that the food is produced at too high a price. And it is a political crisis as well because a major part of the voters think subsidies and trade barriers are too high. The paper argues that beneath the present agricultural and rural policy crisis lies the failure of three great projects of our time: 1) The project of natural science; 2) The project of liberal capitalism; and 3) The project of scientific socialism. The failure of these three projects has to do with the breakdown of the positivist idea of modernization. Modernization theory was partly wrong because it overlooked the persistence of locally based life modes. Those life modes must be understood before a sustainable rural development is found. The article reviews some contemporary social science perspectives that have recently been developed to grasp the fundamental changes of today's rural societies. Based on those perspectives and primarily the life mode perspective, five key elements that are essential to analyze if we want to understand future development are isolated: food production, resources, space, social diversity, and culture.Reidar Almås is a Professor of Sociology at the University of Trondheim, Norway, where he directs the Center for Rural Research. He received his Dr. philos. at the University of Trondheim with a dissertation on group farms. Almås is now doing research on food policies, rural development, and public perception of biotechnology. In addition to several books in Norwegian, he has publishedRural Norway, a gift to Europe. Fifteen selected articles on rural persistence and change.     

Assessment of Carbon Balance in Community Forests in Dolakha, Nepal

This study assessed the net above-ground carbon stock in six community forests in the Dolakha district, Nepal. A survey was conducted of above-ground timber species, using random sampling. A tree-ring chronology for Pinus roxburghii was created to construct a growth model representative of the various mainly-pine species. The allometric model combined with tree ring analysis was used to estimate carbon stock and annual growth in the above-ground tree biomass. The out-take of forest biomass for construction material and fuelwood was estimated on the basis of interviews and official records of community forest user groups. The average annual carbon increment of the community forests was 2.19 ton/ha, and the average annual carbon out-take of timber and fuelwood was 0.25 ton/ha. The net average carbon balance of 1.94 ton/ha was equivalent to 117.44 tons of carbon per community forest annually. All the community forests were actively managed leading to a sustainable forest institution, which acts as a carbon sink. It is concluded that community forests have the potential to reduce emissions by avoiding deforestation and forest degradation, enhance forest carbon sink and improve livelihoods for local communities.     

Sudden change in long‐term ocean climate fluctuations corresponds with ecosystem alterations and reduced recruitment in Norwegian spring‐spawning herring (Clupea harengus,Clupeidae)

Fish stocks vary in abundance. The causes behind the fluctuations may be difficult to determine, especially ones caused by natural fluctuations, but long‐term data series may provide indications of the mechanisms. Assessments show that the recruitment to the Norwegian spring‐spawning herring (Clupea harengus, Clupeidae) has remained low since 2004, a year which produced the last really rich year‐class. Long time‐series of estimated recruitment and mean winter temperature in the ocean showed a significant positive correlation for the period 1921–2004. Here, we show that this positive correlation did not continue from 2005 onwards as the winter temperature increased to high levels while herring recruitment decreased and has remained low. The density of zooplankton in the drift route of the herring larvae dropped significantly after 2004, and their centre of gravity shifted northwards. There may currently be heavy predation on the larvae by Atlanic mackerel (Scomber scombrus, Scombridae), and top‐down regulation is suggested to hamper successful recruitment. Our analysis indicates that the presence of food and overlap with high food concentrations are likely important regulators of survival in herring larvae. The findings may be important for future management and planning of fisheries of this stock because recruitment failure may continue if temperature remains high and food abundance remains low.     

In vitro studies of Lactobacillus delbrueckii subsp. lactis in Atlantic salmon (Salmo salar L.) foregut: tissue responses and evidence of protection against Aeromonas salmonicida subsp. salmonicida epithelial damage

Probiotic bacteria increase the host health status and protect mucosal tissue against pathogen-caused damage in mammalian models. Using an in vitro (intestinal sac) method this study aimed to address (a) the in vitro ability of Lactobacillus delbrueckii subsp. lactis to remain in the gastrointestinal tract of Atlantic salmon (Salmo salar L.) and (b) its ability to prevent cellular damage caused by successive incubation with Aeromonas salmonicida subsp. salmonicida the causative agent of furunculosis. Short in vitro incubation of salmon foregut with (TRITC)-labelled L. delbrueckii subsp. lactis showed that the probiont was able to colonize the enterocyte surface as studied by confocal microscopy. Furthermore, foregut incubated with the probiotic bacteria only, resulted in a healthy intestinal barrier whereas exposure to A. salmonicida disrupted its integrity. However, pre-treatment of salmon intestine with L. delbrueckii subsp. lactis prevented Aeromonas damaging effects. These results are promising in the context of the use of non-autochthonous probiotic bacteria as prophylactic agents against fish bacterial infections in the gastrointestinal tract.     

Effect of land-use on small mammal abundance and diversity in a forest–farmland mosaic landscape in south-eastern Norway

During the last century the boreal forests of south-eastern Norway have been converted into patchworks of agricultural areas, clear-cuts and even-aged conifer monocultures. Even though Scandinavian forest ecosystems are strongly influenced by small mammals’ dynamics, the effects of anthropogenic changes on these communities are still debated. We conducted an extensive capture–mark–recapture study to examine the relative abundance and distribution of 11 species of small mammals during the reproductive season with respect to all available landscape-scale habitat types and fine-scale vegetation characteristics.