Declining plant species richness of grassland ditch banks—a problem of colonisation or extinction?

Small-scale landscape elements, such as ditch banks are an important remaining source of biodiversity in many agricultural landscapes, including the Western Peat District in the Netherlands. Unfortunately, plant species richness is declining even in these habitats. To understand the factors threatening biodiversity, we studied demographic traits (occupancy, trend, colonisation and extinction) for a large number of plant species, in a 25-year long data set. We developed a method to investigate the relative importance of colonisation and extinction for species increase and decrease in multi-species assemblages. We show that colonisation has been more important for determining species trends than extinction. Decreasing species were small and characterised by low nutrient tolerance and high light requirements, indicating that competitive ability influences species trends. The mechanism by which high nutrient levels reduce plant diversity appears to be closely related to colonisation (germination and seedling establishment). Local management should therefore continue to focus on nutrient reduction and the creation of regeneration sites. Yet, these measures will be insufficient for restoring species richness since isolation also hampers species increase. Therefore, to maximise the effects of local management, additional regional management solutions are required to improve seed dispersal for example, from nature reserves.     

Impact of harvest year on amino acids and sugars in potatoes and effect on acrylamide formation during frying

Acrylamide is formed via the Maillard reaction between reducing sugars and asparagine in a number of carbohydrate-rich foods during heat treatment. High acrylamide levels have been found in potato products processed at high temperatures. To examine the impact of harvest year, information on weather conditions during growth, that is, temperature, precipitation, and light, was collected, together with analytical data on the concentrations of free amino acids and sugars in five potato clones and acrylamide contents in potato chips (commonly known as crisps in Europe). The study was conducted for 3 years (2004-2006). The contents of acrylamide precursors differed between the clones and the three harvest years; the levels of glucose were up to 4.2 times higher in 2006 than in 2004 and 2005, and the levels of fructose were 5.6 times higher, whereas the levels of asparagine varied to different extents. The high levels of sugars in 2006 were probably due to the extreme weather conditions during the growing season, and this was also reflected in acrylamide content that was approximately twice as high as in preceding years. The results indicate that acrylamide formation is dependent not only on the content and relative amounts of sugars and amino acids but also on other factors, for example, the food matrix, which may influence the availability of the reactants to participate in the Maillard reaction.     

The index herd with PMWS in Sweden: Presence of serum amyloid A,circovirus 2 viral load and antibody levels in healthy and PMWS-affected pigs

Background

Postweaning Multisystemic Wasting Syndrome (PMWS) is an emerging disease in pigs of multifactorial origin, but associated to porcine circovirus type 2 (PCV2) infection. PMWS was first diagnosed in Sweden at a progeny test station that received pigs aged five weeks from 19 different nucleus herds on the day after weaning. The objective of this study was to examine, for the first time in an index outbreak of PMWS, the relationship between PCV2 virus, antibodies to PCV2 and serum amyloid a (SAA) in sequentially collected serum samples from pigs with and without signs of PMWS.

Methods

Forty pigs of the last batch that entered the station at a mean age of 37.5 days were monitored for signs of PMWS during the first 55 days after arrival. Serum was collected on six occasions and analysed for presence of PCV2 DNA and antibodies to PCV2, as well as for levels of SAA.

Results

Four of the pigs (10%) were concluded to have developed PMWS, with necropsy confirmation in three of them. These pigs displayed low levels of maternal antibodies to PCV2, more than 10⁷ PCV2 viral DNA copies per ml serum and failed to mount a serological response to the virus. Starting between day 23 and 34 after arrival, an increase in PCV2 viral load was seen in all pigs, but PCV2 did not induce any SAA-response. Pigs that remained healthy seroconverted to PCV2 as the viral load was increased, regardless of initially having low or high levels of PCV2-antibodies.

Conclusion

In this index case of PMWS in Sweden, pigs affected by PMWS were not able to mount a relevant serum antibody response which contributed to the disease progression. The maximal PCV2 virus load was significantly higher and was also detected at an earlier stage in PMWS-affected pigs than in healthy pigs. However, a viral load above 10⁷ PCV2 DNA copies per ml serum was also recorded in 18 out of 34 pigs without any clinical signs of PMWS, suggesting that these pigs were able to initiate a protective immune response to PCV2.     

Bioindication and modelling of atmospheric deposition in forests enable exposure and effect monitoring at high spatial density across scales

Key message

Moss surveys provide spatially dense data on environmental concentrations of heavy metals and nitrogen which, together with other biomonitoring and modelling data, can be used for indicating deposition to terrestrial ecosystems and related effects across time and areas of different spatial extension.

Context

For enhancing the spatial resolution of measuring and mapping atmospheric deposition by technical devices and by modelling, moss is used complementarily as bio-monitor.

Aims

This paper investigated whether nitrogen and heavy metal concentrations derived by biomonitoring of atmospheric deposition are statistically meaningful in terms of compliance with minimum sample size across several spatial levels (objective 1), whether this is also true in terms of geostatistical criteria such as spatial auto-correlation and, by this, estimated values for unsampled locations (objective 2) and whether moss indicates atmospheric deposition in a similar way as modelled deposition, tree foliage and natural surface soil at the European and country level, and whether they indicate site-specific variance due to canopy drip (objective 3).

Methods

Data from modelling and biomonitoring atmospheric deposition were statistically analysed by means of minimum sample size calculation, by geostatistics as well as by bivariate correlation analyses and by multivariate correlation analyses using the Classification and Regression Tree approach and the Random Forests method.

Results

It was found that the compliance of measurements with the minimum sample size varies by spatial scale and element measured. For unsampled locations, estimation could be derived. Statistically significant correlations between concentrations of heavy metals and nitrogen in moss and modelled atmospheric deposition, and concentrations in leaves, needles and soil were found. Significant influence of canopy drip on nitrogen concentration in moss was proven.

Conclusion

Moss surveys should complement modelled atmospheric deposition data as well as other biomonitoring approaches and offer a great potential for various terrestrial monitoring programmes dealing with exposure and effects.

     

Outdoor environments at three nursing homes-qualitative interviews with residents and next of kin

The present study aimed at describing older persons’ experiences of outdoor environments at nursing homes in Sweden in terms of what factors are important and in what way they are important. Twelve residents and seven next of kin from three nursing homes participated in 16 interviews. Two main themes were identified. The first theme, access to nature and surrounding life, describes the outdoor environment as a means for change and as promoting a feeling of freedom. This theme calls for an inspiring design. The second theme, being comfortable in the outdoor environment, describes how important it is that going outdoors can be something easy and natural, and it calls for a comfortable design. The results are intended to facilitate practical knowledge that is useful to planners, decision-makers and care workers striving to create attractive and useable environments that are part of the daily life of nursing home residents. The themes also exemplify how the outdoor environment at nursing homes can serve as a resource in promoting restoration, a feeling of being at home and positive development late in life.     

Separation of selenium, zinc, and copper compounds in bovine whey using size exclusion chromatography linked to inductively coupled plasma mass spectrometry

To study the role of trace elements for the quality and nutritional value of bovine milk, the distribution of selenium, zinc, and copper in whey was investigated using a method linking size exclusion chromatography to inductively coupled plasma mass spectrometry (SEC-ICP-MS). Three major peaks were detected for selenium, two peaks for zinc, and five peaks for copper. More than 65% of the selenium was found in protein fractions, mainly in fractions coinciding with the major whey proteins beta-lactoglobulin and alpha-lactalbumin. All zinc was associated with low molecular weight compounds (<5 kDa) and one of these compounds was probably citrate. More than 60% of the copper eluted in protein fractions and two of the five major peaks probably contained metallothionein and citrate. This method was used to compare milk and whey produced by organic and conventional feeding procedures. The selenium content in whey and desalted milk produced using organic regimens was significantly lower than that in conventional samples. Moreover, the proportion of selenium in protein fractions of organic whey was significantly smaller than that in conventional whey, but the distributions of zinc and copper did not differ. This study showed that with the SEC-ICP-MS technique the distribution profiles of several trace elements in whey could be studied in the same run and that the selenium profile differed in whey produced by organic and conventional procedures.     

Subgroups of canine antinuclear antibodies in relation to laboratory and clinical findings in immune-mediated disease

Background:  Autoimmune system diseases in dogs are commonly referred to as systemic lupus erythematosus (SLE), with a positive antinuclear antibody (ANA) test as a hallmark. In human patients, other systemic ANA-positive diseases with overlapping diagnostic features, referred to as SLE-related diseases, are described.  Objectives:  The objective of this study was to investigate whether different patterns of ANA reactivity represent different systemic autoimmune diseases in dogs. Methods:  Dogs with serum positive for ANA by indirect immunofluorescence (IIF-ANA, titer ≥1:100) (n=56) were identified retrospectively from the patient population at the Department of Small Animal Clinical Sciences, Swedish University of Agricultural Sciences. Dogs were grouped on the basis of ANA staining patterns, and the results of immunodiffusion tests. Clinical, hematologic, serum biochemical, radiologic, and pathologic examinations were described for each group.  Results:  Dogs with a chromosomal–positive, homogeneous ANA staining pattern (n=14) had clinical signs involving multiple organ systems; 8 dogs were anemic. Dogs with a speckled IIF-ANA staining pattern (n=42) primarily had clinical signs of musculoskeletal disorders, fatigue and fever. Precipitating antibodies by immunodiffusion were found only in dogs with a speckled IIF-ANA staining pattern and comprised 4 different subgroups based on antigen specificity. Conclusions: In dogs with homogeneous IIF-ANA staining, SLE is a probable diagnosis because of the diversity of clinical manifestations and autoantibody reactivity against chromosomal antigens. Dogs with a speckled IIF-ANA pattern may have SLE-related diseases, which, in turn, may be correlated with different immunodiffusion subgroups. These syndromes had overlapping clinicopathologic features, as described for human patients.     

Effects of seedbed substrate on moisture conditions and germination of Scots pine (Pinus sylvestris) seeds in a mixed conifer stand

The objective of this investigation was to comparemoisture conditions and Scots pine (Pinussylvestris L.) seed germination percentages in fourtypes of seedbed substrates, (i.e., feather mosses,mineral soil, humus, and ground organic material). Twoexperiments were conducted, with and withoutirrigation, in the summer of 1996 in a stand innorthern Sweden. The moisture conditions weredetermined by periodically weighing seedsamples. When plots were not irrigated, no seedsgerminated, probably because conditions were too dryin the seedbeds, as indicated by the low seed moisturecontent (under 15%). However, during rainy days, seedmoisture contents were relatively high (20–45%). Onthe irrigated plots the seeds germinated on allseedbed substrates, with the best germinationoccurring in humus (about 40%). Seed moisturecontents were high and relatively consistent in allirrigated seedbed substrates (35–55%). Inirrigated plots temperature rather than moisture, wasa limiting factor, and germination was highest in thewarmest seedbed types which are generally regarded aspoor germination substrates. We suggest that seedbedsin areas scheduled for harvesting be prepared in thestand before clear-cutting, and that the preparationshould enhance not only the substrates's water-holdingcapacity, but its thermal conductivity as well.     

Influence of veneer orientation on shape stability of plane laminated veneer products

One of the most important quality aspects of a laminated veneer product is its shape stability under changing relative humidity (RH). This study aimed to establish an understanding of how the orientation of individual veneers in the laminate, i.e., orientation according to fibre orientation and orientation of the loose (the side with ‘lathe checks’) or tight side of the veneer, affects the shape stability. Three-ply laminates from peeled veneers of beech (Fagus sylvatica L.) were studied. The four types of laminate were the following: loose sides of all veneers in the same direction (cross and parallel centre ply) and loose sides of the outer veneers facing inward (cross and parallel centre ply). Four replicates of each type yielded 16 samples. The samples were exposed to RH cycling at 20% and 85% RH at 20°C, and the shapes of the samples were determined. The shape stability was influenced by the veneer orientation. Laminations with the middle veneer perpendicular to the top and bottom veneer (cross-laminated) showed the best shape stability, especially when the loose sides of the veneers were oriented the same direction. In parallel-laminated veneers, the laminates with opposite directions of the loose sides in the two outermost veneers showed the best shape stability. The major explanation of the behaviour of the laminates is that the loose side expanded more than the tight side from the dry to the humid climate, which was shown by optical 3D deformation analysis (ARAMIS^TM). After RH cycling, the laminates with cross plies showed visible surface checks only when the tight side was facing outwards.