The effects of clear-cutting on stream-water chemistry in northern Sweden remain largely unexplored. Here we report data collected during a reference period and the first two years after logging in two typical partially harvested northern catchments; the objective was to compare water chemistry along the stream with and without a forest buffer. Two typical uncut reference catchments are included for comparison. Runoff was measured at the outlet of each catchment, and water samples were generally taken every second week and analyzed for 20 constituents. Logging resulted in increased runoff and increased concentrations of sodium, potassium, chloride, total nitrogen, total phosphorus, and suspended material from both catchments. Nitrate (NO3-) leaching increased only from the catchment without a forest buffer. It has not yet been possible to evaluate fully the effects of the forest buffer on the NO3- leaching because the uphill clear-cut area leached minimal amounts of NO3-.

African swine fever (ASF) is one of the most important pig diseases, causing high case fatality rate and trade restrictions upon reported outbreaks. In Uganda, a low-income country with the largest pig population in East Africa, ASF is endemic. Animal disease impact is multidimensional and include social and economic impact along the value chain. In low-income settings, this impact keep people poor and push those that have managed to escape poverty back again. If the diseases can be controlled, their negative consequences can be mitigated. However, to successfully argue for investment in disease control, its cost-benefits need to be demonstrated. One part in the cost-benefit equations is disease impact quantification. The objective of this study was therefore to investigate the socio-economic impact of ASF outbreaks at household level in northern Uganda. In a longitudinal study, structured interviews with two hundred, randomly selected, pig-keeping households were undertaken three times with a six month interval. Questions related to family and pig herd demographics, pig trade and pig business. Associations between ASF outbreaks and economic and social impact variables were evaluated using linear regression models. The study showed that pigs were kept in extreme low-input-low-output farming systems involving only small monetary investments. Yearly incidence of ASF on household level was 19%. Increasing herd size was positively associated with higher economic output. The interaction between ASF outbreaks and the herd size showed that ASF outbreaks were negatively associated with economic output at the second interview occasion and with one out of two economic impact variables at the third interview occasion. No significant associations between the social impact variables included in the study and ASF outbreaks could be established. Trade and consumption of sick and dead pigs were coping strategies used to minimize losses of capital and animal protein. The results indicate that causality of social and economic impact of ASF outbreaks in smallholder systems is complex. Pigs are mostly kept as passive investments rather than active working capital, complicating economic analyses and further disqualifying disease control arguments based only on standard economic models.

The applications of data on biological variation include assessment of the utility of population-based reference intervals, evaluation of the significance of change in serial results, and setting of analytical quality specifications. We investigated the biological variation of 19 biochemistry analytes and total T4, measured in serum from 7 clinically healthy domestic cats sampled once weekly for 5 weeks. Samples were frozen and analyzed in random order in the same analytical run. Results were analyzed for outliers, and the components of variance, subsequently generated by restricted maximum likelihood, were used to determine within-subject and between-subject variation (CV and CV, respectively), as well as analytical variation (CV) for each analyte. Indices of individuality, reference change values, and analytical performance goals were calculated. The smallest CV and CV were found for calcium, chloride, and sodium, whereas the largest values were calculated for bile acids. Nine analytes (albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, cholesterol, creatinine, phosphate [phosphorus], total protein, total T4) demonstrated high individuality, indicating limited utility of population-based reference intervals. Individuality was low, and population-based reference intervals were thereby considered appropriate for 5 analytes (bile acids, calcium, fructosamine, glucose, potassium). The intermediate individuality observed for 4 analytes (creatine kinase, iron, magnesium, urea) indicated that population-based reference intervals should be used with caution.

Forestry operations can increase the export of mercury (both total and methyl) to surface waters. However, little is known about the relative contribution of different forestry practices. We address this question using a paired-catchment study that distinguishes the effects of site preparation from the antecedent logging. Runoff water from three catchments, two harvested and one untreated control, was sampled biweekly during one year prior to logging, two years after logging, and three years after site preparation. The logging alone did not significantly increase the concentrations of either total or methyl-mercury in runoff, but export increased by 50-70% in one of the harvested catchments as a consequence of increased runoff volume. The combined effects of logging and site preparation increased total and methyl-mercury concentrations by 30-50% relative to preharvest conditions in both treated catchments. The more pronounced concentration effect after site preparation compared to logging could be related to site preparation being conducted during summer. This caused more soil disturbance than logging, which was done during winter with snow covering the ground. The results suggest that the cumulative impact of forest harvest on catchment mercury outputs depends on when and how forestry operations are implemented.

No abstract

Ash dieback is a recent widespread disease on ash (Fraxinus sp.) that is causing important economic and ecological losses throughout Europe. The disease is initiated by the ascomycetous fungus Hymenoscyphus pseudoalbidus (anamorph Chalara fraxinea). The main aim of this study was to investigate seasonal pattern of lesion development associated with ash dieback. We present data on the spread of 324 natural lesions in ash shoots, branches and stems surveyed over a 32 month period. Most lesions were active and showed the greatest rate of growth during the summer; however, lesions were active throughout the year. Tree mortality was high, with more than a third of the surveyed trees dying during the study. Although many lesions permanently ceased to develop, the rate at which new lesions emerged was greater than the rate at which lesions entered a resting phase. The most common cause for a lesion going into a permanent state of rest was that it had encountered a branch-base. Genotype analysis showed that multiple infections can occur in a single tree given that different genotypes were identified in different lesions as well as in single lesions. A weak positive correlation was noted between tree health and tree size and a weak negative correlation was noted between tree overall health and lesion activity. The lower limit for H. pseudoalbidus growth in culture was between 4.0°C and 0.5°C.

Forest harvest is hypothesized to increase the mercury (Hg) load in aquatic ecosystems. The Balsjö paired catchment study examined the outputs of methylmercury (MeHg) and total mercury (Hg(tot)) from two boreal catchments during the 2 y following forest harvest but prior to site preparation. This enabled us to separate the effect of the two operations that followed best management practices. Hg(tot) concentrations increased by approximately 15%, and fluxes by 20-30%. The MeHg concentrations and fluxes either declined or increased by up to 60%, depending on whether annual MeHg peaks during summer low flows were considered to have been influenced by forest harvest. The lack of a severalfold increase in Hg outputs after forest harvest, as reported from other sites, may be the result of minimal soil disturbance during the winter forest harvest operations. If so, there may be a greater Hg response after soil scarification to prepare for planting.

No abstract