Glacial survival of boreal trees in northern Scandinavia

It is commonly believed that trees were absent in Scandinavia during the last glaciation and first recolonized the Scandinavian Peninsula with the retreat of its ice sheet some 9000 years ago. Here, we show the presence of a rare mitochondrial DNA haplotype of spruce that appears unique to Scandinavia and with its highest frequency to the west-an area believed to sustain ice-free refugia during most of the last ice age. We further show the survival of DNA from this haplotype in lake sediments and pollen of Tr?ndelag in central Norway dating back ~10,300 years and chloroplast DNA of pine and spruce in lake sediments adjacent to the ice-free And?ya refugium in northwestern Norway as early as ~22,000 and 17,700 years ago, respectively. Our findings imply that conifer trees survived in ice-free refugia of Scandinavia during the last glaciation, challenging current views on survival and spread of trees as a response to climate changes.     

Pimpinella saxifraga is maintained in road verges by mosaic management

Road verges have been proposed as refuges for vulnerable grassland species in the modern, changing landscape, but little comparative knowledge exists on how management regimes affect population dynamics of such species. We compared the effects of various management regimes on the population dynamics of Pimpinella saxifraga in road verges and pastures, using elasticities and LTRE analyses with underlying vital rates as model components in three road verges and three pastures in an agricultural landscape in W Norway. Under present management regimes, we observed slightly higher population growth rates in pastures than in road verges. The pasture populations had comparatively lower survival but higher reproduction than the road verge populations, thus demonstrating a management-induced negative correlation. Such negative correlations may reflect species’ adaptability to environment changes, thereby reducing the extinction risk. We generally observed small changes in P. saxifraga demography to management but considerable variation along environmental gradients, underlining the importance of studying multiple populations. The linear form of the road verges enabled a fine-scale mosaic application of different management regimes. Individuals growing in zones receiving survival-lowering management produced seeds that compensated the lack of seeds in zones receiving fertility-lowering management. The observation of ‘mosaic’ management that allows road verge metapopulations to complement each others life-history characteristics exemplifies the unique potential of road verge ecosystems to maintain semi-natural grassland species like P. saxifraga, as well as providing habitats for different species exhibiting various life histories.     

The wood-decaying fungus Hygrophoropsis aurantiaca increases P availability in acid forest humus soil, while N addition hampers this effect

We evaluated the influence of the brown rot fungus Hygrophoropsis aurantiaca on P solubility in the humus layer of a podzolic forest soil. This fungus is known to exude large amounts of oxalic acid that may stimulate weathering of minerals and increase dissolution of humus, which in turn may increase P availability in the soil surrounding the fungus. Humus was inoculated using small wooden pieces colonised by the fungus. The presence of the fungus resulted in elevated concentration of PO₄⁻ in the humus solution. In a second experiment birch seedlings grown in the same humus were able to utilise the PO₄⁻ mobilised by the fungus to increase their internal P content. The factor determining this increased P uptake and the increased available P might be oxalate produced by fungus. The acid may directly dissolve P or change organic forms of P making it more susceptible to reaction with phosphatases. This fungal effect on P solubility diminished when N was added to the soil in the form of a slow release N fertilizer (methyl urea), or when a soil with a higher soil N concentration was used. We found a strong correlation between NH₄⁺ concentration and total organic carbon in the soil solution at high NH₄⁺ concentrations, suggesting the dissolution of humus as a result of the high NH₄⁺ content in the solution. This study demonstrates that the wood-decaying fungus H. aurantiaca influences nutrient turnover in forest soil, and thereby nutrient uptake by forest trees. An intensified harvest of forest products such as whole tree harvesting may decrease the active biomass of the wood decomposers and may thereby change the availability of P and the leaching of N.     

Phage therapy in the fields of veterinary medicine: an overview

During the last years, bacteriophages have been used as valuable tool in microbiological diagnostics and basic research. Even though the potential of bacteriophages for fighting bacterial pathogens is known for a long time, the phage therapy is not used in daily routine worldwide. Due to the continuing spread of bacterial resistance to antimicrobials and an increasing awareness of the necessity to protect consumers' health, the phage therapy meanwhile has become a subject of major interest in veterinary medicine, too.This article is meant to present fields of application for phage therapy as well as current trends of development in the field of livestock animals.     

The precision and robustness of published protocols for disc diffusion assays of antimicrobial agent susceptibility: an inter-laboratory study

The precision of the disc diffusion protocols previously published by Alderman and Smith (Aquaculture 196 (2002) 211) was analysed in a seven-laboratory trial using Escherichia coli ATCC 25922 as the test strain. Discs containing seven antimicrobial agents were employed and 2899 zone size measurements were generated. The total data generated in the trial was used to quantify the intra- and inter-laboratory precisions. The study design also facilitated the investigation of the influence of the source of media and the source of discs on zone sizes. A smaller two-laboratory trial was employed to investigate the influence of incubation time of zone size.

The intra-laboratory precision was relatively high with the mean of the coefficients of variation calculated for each laboratory and each agent being 4.7%. In contrast, the inter-laboratory precision was very much lower with the mean of the values for each agent being 11.1%. Significant influences on zone size were detected for all three parameters of the protocol. Media source effects were particularly notable with respect to oxytetracycline and oxolinic acid discs, disc source effects with respect to ampicillin and sulphamethoxazole/trimethoprim discs and incubation times with the ampicillin and amoxycillin discs. ANOVA analysis of the total data set confirmed that inter-laboratory variation was the major factor influencing the low precision of the protocol.

The overall precision of the protocols used here was found to be significantly lower than that implied by the control limits associated with the same bacterium in other validated disc diffusion protocols. The implications of these results, for the further development of the protocols under investigation, are discussed.     

Sprouting Dynamics of Bunias orientalis

Journal of Plant Diseases and Protection - Bunias orientalis is a highly vigorous weed and the powerful taproot makes control difficult. Taking action against unwanted plant species at the...     

Outside enclosure and additional enrichment for dairy goats – a preliminary study

Background

Dairy goats are commonly housed at a space allowance of 0.7 – 0.8 m²/goat in commercial Norwegian goat herds, which is very low compared to regulations and recommendations in other European countries. One easy and cheap way to increase space allowance is to allow the animals’ access to outdoor area. The aim of this study was to investigate the effect of access to an outside enclosure and environmental enrichment for dairy goats kept in slatted floor pens with low space allowance on their activity pattern and social behaviour.

Methods

A group of 82 dairy goats on a commercial Norwegian dairy farm were kept inside during the winter period from October to April. In April the goats were given access to an outside enclosure for 8 hours per day. After having access to the enclosure for another for two days, enrichment (branches) was provided, and after 19 days the enrichment were removed. The goats were observed for 5 hours per day for the two last days before they got access to the outside enclosure, the two days in the enclosure, the two first and the two last days with enrichment and for the following two days without enrichment by two trained observers.

Results

When allowed access to the enclosure, the goats spent nearly 50% of the time outside, and later the time spent outside was reduced to less than 40% (P < 0.0001), but there was no clear effect of enrichment. All the goats appeared to have a regular use of the enclosure. Time spent resting decreased 59.2% to only 25.2% when the goats first got access to the enclosure, but then started to increase again (P < 0.0001). Initially time spent exploring and chewing the branches was 20%, but this was reduced to around 12% in the last part of the ENRICH period (P < 0.0001). Number of aggressive interactions tended to increase when the goats were allowed access to the outdoor enclosure whereas play behaviour was only observed in the outside enclosure (P < 0.05).

Conclusions

In conclusion, the goats preferred to use the outside enclosure when being active, and branches were perceived as an attractive enrichment.     

Effect of feeding different levels of foliage from Erythrina variegata on the performance of growing goats

The effect of feeding different levels of foliage from Erythrina variegata on the performance of growing goats was studied using a local breed (Ma T'ou) with an average initial body weight of 11.2?kg (SD?=?0.9). Twenty-four animals were allocated to a randomized design, with six animals (three males and three females) per treatment. The treatments were four different levels of replacement of the diet crude protein (CP) with CP from Erythrina foliage (EF) at 0?% (E-0), 20?% (E-20), 40?% (E-40), and 60?% (E-60). There were no significant differences in the dry matter (DM) intake between treatments, but total CP intake was significantly higher in the goats fed the diet E-60 compared to E-20 (61.1 and 51.4?g/day, respectively). The average daily liveweight gain of the goats did not differ between treatments and ranged from 51 to 63?g/day. Sixteen animals were kept in metabolism cages for a digestibility study and given with the same four diets as in the main experiment. The digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber was significantly higher for diet E-60 than for E-0. Neither the apparent digestibility of CP and N retention nor carcass characteristics (16 animals) differed with an increase in the level of CP from EF in the diets. In conclusion, CP from EF can replace up to 60?% of CP from a mixed diet with soybean meal without any negative effect on the growth in goats.