A climate for commerce: the political agronomy of conservation agriculture in Zambia

The promotion of conservation agriculture (CA) for smallholders in sub-Saharan Africa is subject to ongoing scholarly and public debate regarding the evidence-base and the agenda-setting power of involved stakeholders. We undertake a political analysis of CA in Zambia that combines a qualitative case study of a flagship CA initiative with a quantitative analysis of a nationally representative dataset on agricultural practices. This analysis moves from an investigation of the knowledge politics to a study of how the political agendas of the actors involved are shaping agrarian practices. From its initial focus on CA as soil conservation and sustainable agriculture, the framing of the initiative has evolved to accommodate shifting trends in the policy arena. In tandem with the increased focus on climate adaptation, we see an increased emphasis on private sector-led modernisation. The initiative has shifted its target group from the poorest smallholders to prospective commercial farmers, and has forged connections between its farmer-to-farmer extension network and private input suppliers and service providers. The link between CA and input intensification is reflected in national statistics as a significantly higher usage of herbicides, pesticides and mineral fertilizer on fields under CA tillage compared to other fields. We argue that the environmental and participation agendas are used to buttress CA as an environmentally and socially sustainable agricultural development strategy, while the prevailing practice is the result of a common vision for a private sector-led agricultural development shared between the implementing organisation, the donor and international organisations promoting a new green revolution in Africa.     

Thresholds in nesting habitat requirements of an old forest specialist, the Brown Creeper (Certhia americana), as conservation targets

Many bird species respond to forestry, even at moderate intensities. In New Brunswick, Canada, the Brown Creeper exhibits a negative, threshold response to harvesting intensity. This study aimed to determine whether (a) the threshold found in Brown Creeper occurrence is lower than eventual thresholds in its nesting requirements, and whether (b) the conservation of this species could be achieved through moderate-intensity harvest systems. Creepers are particularly sensitive to forestry because they nest on snags with peeling bark and they mainly forage on large-diameter trees. In northern hardwood stands, we compared habitat structure at local- (r = 80 m) and neighbourhood-scales (r = 250 m) around nest sites and sites not used by creepers. Over two years, we found 76 nests, 66 of which were paired with unused sites for comparison. At the local scale, densities of trees 30 cm dbh and snags 10 cm dbh, and the probability of presence of potential nest sites were significantly higher near nests than at sites where no creepers were detected. At the neighbourhood scale, the area of untreated mature forest was significantly higher around nests. Variance decomposition indicated that habitat variables at the local scale accounted for the majority of explained variation in nest site selection. We also found significant thresholds in the densities of large trees (127/ha) and snags (56/ha), and in the area of mature forest (10.4 ha). The conservation of breeding populations of Brown Creepers may thus require densities of large trees nearly twice as high as those associated with its probability of presence. Such a target seems to be incompatible even with moderate-intensity harvesting.     

Unterschiede im Befall der Fichtengallenlaus Sacchiphantes abietis L. an Fichtenkreuzungen

Zusammenfassung An jungen Fichten 9 verschiedener Kreuzungen wurde das Vorkommen von Gallen vonSacchiphantes abietis L. untersucht. Es traten genetisch bedingte Unterschiede in der Stärke des Gallenbefalls auf. Die Häufigkeit der Gallen war nicht vom Zeitpunkt des Knospenaustriebs abhängig. Fichten mit Gallenbesatz hatten im Durchschnitt besseren Höhenzuwachs als Bäume ohne Gallen. Gallen m Gipfeltrieb hemmten den Höhenzuwachs. Die Stärke des Gallenbefalls war positiv von dem Vorkommen von Prolepsis beeinflußt. Es bestanden Beziehungen zwischen der Häufigkeit der Gallen und der Anzahl überwinterder Läuse.

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Differences in attack of the spruce gall aphid Sacchiphantes abietis L. in a Norway spruce progeny trial

The occurence of galls caused by the spruce gall aphid (Sacchiphantes abietis L.) was studied on young Norway spruce progeny from 9 different full sib families with parents from Sweden and Western Europe. The frequency of galls was found to vary significantly with genetic origin. Time for bud flushing did not influence the frequency of galls. Attacked trees had on verage better height increment than trees without galls. Galls on the leading shoot reduced height increment. The frequency of galls was positively influenced by the occurence of prolepsis. The abundance of hibernating aphids was positively correlated to the frequency of galls.

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Mit 4 Abbildungen und 6 Tabellen     

Isolation, biochemical and serological characterisation of Plesiomonas shigelloides from freshwater in Northern Europe

Isolation and characterisation of Plesiomonas shigelloides from fresh water in Northern Europe is reported in this study. The organisms were isolated from two lakes and a river in Sweden. All isolates of P. shigelloides showed an identical biochemical profile and belonged to different serotypes, namely, O18, O23, O26, O58 and O60. The study indicates that P. shigelloides may occur in the aquatic environment of cold climates and as a result, it is likely to be associated with human infections caused by waterborne pathogens in geographical areas with similar climatic conditions.     

Development strategies for privately owned forestry in the mountainous region of Sweden

Forestry in Sweden as well as in other European countries is characterised by intense and increasing international competition resulting in decreasing roundwood prices in real terms. This is especially the situation in the mountainous region of Sweden with long transportation distances between the felling site and the processing industries located at the coast. The question arises whether forestry must be run more extensively than at present to achieve the optimal rate of silvicultural activities compared with the amount of timber cut. With this in mind, optimising economic analyses have been performed at the stand level as well as at the level of forest estates. Results of the analyses reveal that more intensive thinning (more frequent operations) and shorter rotation periods would increase profit and offset continuously decreasing roundwood prices. Intensive pre-commercial thinning (cleaning) is especially important for profitability of the subsequent thinnings and the final cut. The large number of cuts during the rotation will increase logging costs. However, this will be more than offset by the increasing production of economically matured dimensions of timber, an effect that will be still more pronounced when using new harvesting technology. Moreover, frequent high thinning operations (thinning ‘from above’ or removal of dominant trees) will result in more dense wood close to the pith, more evenly distributed year rings, and fewer and smaller knots in the lower part of the stem — in other words more valuable roundwood which will justify high transportation costs. Several biological and technical aspects of these treatment programs are discussed in the paper.     

Effects of temporal aggregation in integrated strategic/tactical and strategic forest planning

Integrated approaches to forest planning lead to large models and there is a subsequent need for a reduction of the number of constraints and variables. One way of achieving this is to aggregate data, either spatially or temporally. In this paper an integrated forest planning mixed integer model that takes into account both long-term strategic and shorter-term tactical forest management decisions is utilised. The study analyses the consequences of temporal aggregation in the strategic part of the integrated model, whereas the tactical part is modelled by a fixed set of years divided into seasons. For reference, analyses are also made using a pure strategic linear programming model. Cases using both equal and variable strategic period lengths are presented, and two case study areas are used. Results indicate that integrated plans, as well as strategic plans, are not particularly affected by the number of equal length strategic periods when more than five periods, i.e. less than 20 year period length, are used. When modelling strategic and integrated problems using variable-length periods, care should be taken to ensure that harvest operations late in the planning horizon get enough timing options to be adequately described.     

Effects of dietary marine microalgae,Tetraselmis suecica,on production,gene expression,protein markers and bacterial count of Pacific white shrimp Litopenaeus vannamei

The marine flagellated Chlorophyta Tetraselmis suecica is among the most important live food species in marine aquaculture. In the present study, the effects of dietary supplementation of dried marine microalgae, Tetraselmis suecica, on growth performance; feed utilization; chemical composition; gene expression of superoxide dismutase (SOD), glutathione peroxidase (GPx) and insulin‐like growth factor 2 (IGF‐II) gene of Pacific white shrimp, Litopenaeus vannamei; muscle protein polymorphism; and microbial count were assessed and evaluated. Three hundred and sixty L. vannamei (postlarvae) Pls (0.124 ± 0.002 g) were randomly stocked into 40‐L glass aquaria (30 shrimp/aquarium) and fed three times daily four tested diets: a basal diet (control), diet incorporated with 2.5 g kg^?1 dried T. suecica (T1), 5 g kg^?1 dried T. suecica (T2) and 7.5 g kg^?1 dried T. suecica (T3) in triplicates, for 90 days. At the end of the trial, the survival rate (SR) of L. vannamei fed diets supplemented with different levels of T. suecica was significantly (p < .05) higher than the control diet. The highest weight gain and specific growth rate and the best feed conversion ratio were recorded on L. vannamei fed a diet supplemented with a 7.5 g/kg dried T. suecica. The highest protein, lipid and ash contents were obtained in L. vannamei fed the diet containing 7.5 g/kg T. suecica, when compared with the remaining tested diets. The gene expression of antioxidant genes SOD and GPx was the lowest in the T3 group in comparison with the control group. Meanwhile, expression level of IGF‐II was higher in the T2 group. The total heterotrophic bacterial count was significantly (p < .05) increased with the cumulative T. suecica level, while no significant (p > .05) differences were found in the total Vibrio count among treatments. Overall, the present results have shown that the diet supplemented with the highest inclusion level of dried T. suecica resulted in improved growth and nutrient utilization.     

Prospects for the future of pink salmon in three oceans: From the native Pacific to the novel Arctic and Atlantic

While populations of other migratory salmonids suffer in the Anthropocene, pink salmon (Oncorhynchus gorbusca Salmonidae) are thriving, and their distribution is expanding both within their natural range and in the Atlantic and Arctic following introduction of the species to the White Sea in the 1950s. Pink salmon are now rapidly spreading in Europe and even across the ocean to North America. Large numbers of pink salmon breed in Norwegian rivers and small numbers of individuals have been captured throughout the North Atlantic since 2017. Although little is known about the biology and ecology of the pink salmon in its novel distribution, the impacts of the species' introduction are potentially highly significant for native species and watershed productivity. Contrasts between pink salmon in the native and extended ranges will be key to navigating management strategies for Atlantic nations where the pink salmon is entrenching itself among the fish fauna, posing potential threats to native fish communities. One key conclusion of this paper is that the species' heritable traits are rapidly selected and drive local adaptation and evolution. Within the Atlantic region, this may facilitate further establishment and spread. The invasion of pink salmon in the Atlantic basin is ultimately a massive ecological experiment and one of the first examples of a major faunal change in the North Atlantic Ocean that is already undergoing rapid changes due to other anthropogenic stressors. New research is urgently needed to understand the role and potential future impacts of pink salmon in Atlantic ecosystems.     

Changes in Phytoavailability and Concentration of Cadmium in Soil Following Long Term Salix Cropping

Cadmium concentrations in Salix (willow) shoots are generally high and Salix can therefore potentially remove significant amounts of Cd from soil. The aim of this study was to investigate how long-term Salix cultivation had affected total and plant available Cd concentrations in agricultural soil. The study was made in 8 to 30 yr old plantations. Soil profiles down to 65 cm depth were sampled and conditions within the plantations were compared to those in nearby reference areas. When consideration was given to certain pH differences, concentrations of exchangeable Cd throughout the soil profiles were significantly lower in the Salix stands than in the reference areas. However, the effect on concentrations of total Cd was negligible. The yield levels proved not to be optimal and Cd concentrations in shoots were lower than average in the investigated stands. Data on exchangeable Cd show that uptake occurs throughout the soil profile and the Cd pool involved is thus large. These facts may explain why total concentrations were only slightly influenced. The conclusion reached was that Salix cultivation reduces the amount of plant-available Cd in the soil. However, more investigations are needed to evaluate how this effect can be optimized by choice of clone and other management measures.     

In vitro evaluation of five canine tibial plateau leveling methods

OBJECTIVE: To compare application time, accuracy of tibial plateau slope (TPS) correction, presence and magnitude of rotational and angular deformities, and mechanical properties of 5 canine tibial plateau leveling methods. SAMPLE POPULATION: 27 canine tibial replicas created by rapid prototyping methods. PROCEDURE: The application time, accuracy of TPS correction, presence and magnitude of rotational and angular deformation, and construct axial stiffness of 3 internal fixation methods (tibial plateau leveling osteotomy, tibial wedge osteotomy, and chevron wedge osteotomy [CWO]) and 2 external skeletal fixation (ESF) methods (hinged hybrid circular external fixation and wedge osteotomy linear fixation [WOLF]) were assessed. RESULTS: Mean bone model axial stiffness did not differ among methods. Mean application time was more rapid for WOLF than for other methods. Mean TPSs did not differ from our 5 degrees target and were lower for ESF methods, compared with internal fixation methods. Mean postoperative rotational malalignment did not differ from our target or among groups. Mean postoperative medio-lateral angulation did not differ from our target, except for CWO. Internal fixation methods lead to axially stiffer constructs than ESF methods. Reuse of ESF frames did not lead to a decrease in axial stiffness. CONCLUSIONS AND CLINICAL RELEVANCE: The 5 tibial plateau leveling methods had acceptable geometric and mechanical properties. External skeletal fixation methods were more accurate as a result of precise data available for determining the exact magnitude of correction required to achieve a 5 degrees TPS.