Urban Forestry Research in Europe-An Overview

A comprehensive European overview of recent and ongoing research in Europe has been carried out within the framework of COST Action E12 'Urban Forests and Trees', a pan-European research network. This paper presents some of the main findings of a comparative analysis of 20 individual country reports. The analysis shows that research on urban forests and urban trees in Europe has a wide scope and is rather fragmented and uncoordinated. Universities and state research institutes, mostly with a forestry or horticultural background, dominate the research. Relevant research is primarily funded from state and municipal sources. Significant differences exist between countries with regards to the level of activity, research topics and institutions involved.     

Toward sustainable harvest strategies for marine fisheries that include recreational fishing

Recreational fishing (RF) is a large yet undervalued component of fisheries globally. While progress has been made in monitoring, assessing, and managing the sector in isolation, integration of RF into the management of multi-sector fisheries has been limited, particularly relative to the commercial sector. This marginalises recreational fishers and reduces the likelihood of achieving the sector's objectives and, more broadly, achieving fisheries sustainability. We examined the nature and extent of RF inclusion in harvest strategies (HSs) for marine fisheries across 15 regions in 11 nations to define the gap in inclusion that has developed between sectors. We focused on high-income nations with a high level of RF governance and used a questionnaire to elicit expert knowledge on HSs due to the paucity of published documents. In total, 339 HSs were considered. We found that RF inclusion in HSs was more similar to the small-scale sector (i.e., artisanal, cultural, or subsistence) than the commercial sector, with explicit operational objectives, data collection, performance indicators, reference points, and management controls lacking in many regions. Where specified, RF objectives focused on sustainability, economic value and catch allocation rather than directly relating to the recreational fishing experience. Conflicts with other sectors included competition with the commercial sector for limited resources, highlighting the importance of equitable resource allocation policies alongside HSs. We propose that RF be explicitly incorporated into HSs to ensure fisheries are ecologically, economically, and socially sustainable, and we recommend that fisheries organisations urgently review HSs for marine fisheries with a recreational component to close the harvest strategy gap among sectors.     

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.     

Microbial environments in marine larviculture:Impacts of algal growth rates on the bacterial load in six microalgae

The impacts of varying algal growth rates on the bacterial load in the cultures were studied for six marine microalgae: Skeletonema costatum ,Chaetoceros mülleri (Bacillariophyceae), Nannochloropsis oculata (Eustigmatophyceae), Isochrysis galbana, Pavlova lutheri (Haptophyceae), and Tetraselmis sp. (Prasinophyceae). Samples were taken in batch cultures during early exponential phase and in stationary phase when the growth rate was below 5% of maximum growth rate (µ_max). Except for C. mülleri and N. oculata, the microalgae were thereafter grown semi-continuously at dilution rates of 20% and 60% of µ_max and samples taken during a period of 10 days.Higher bacterial levels were associated with slow-growing microalgae on a per volume basis. Per algal cell, variations in the bacterial load were more related to species. Relatively high bacterial densities (5.7–16.4 CFU algal cell^–1) with large proportions of opportunistic and haemolytic species were associated with the Bacillariophyceae. For the other species, the bacterial density was 0.2–4.3 CFU algal cell^–1. Bacterial levels were in general lower and not affected to the same extent by algal growth conditions in Tetraselmis sp. and P. lutheri. No or very low levels of presumptive Vibrio spp. were observed, except in semi-continuous cultures of P. lutheri. Cultures of Tetraselmis sp. had low levels of opportunistic bacteria at all growth conditions.     

Peptones from Atlantic Cod Stomach as Nitrogen Sources in Growth Media to Marine Bacteria

Peptones were obtained from cod stomachs as a by-product during enzyme production. Minced cod stomachs were autolyzed after acidification with either formic or phosphoric acid, and low molecular weight (< 10 kDa) peptones were recovered. When formic acid was used, an acid peptone was obtained, whereas phosphoric acid was removed from the peptone after calcium precipitation. The peptones were compared with Proteose Peptone (Difco, Detroit, MI, USA) as nitrogen sources in growth media for three marine bacteria. Two fish pathogens—Vibrio anguillarum and Aeromonas salmonicida—grew equally well or better on the cod stomach peptones, whereas a probiotic lactic acid bacteria (Carnobacterium divergens), isolated from salmon intestines, grew much better on the cod stomach peptones than on Proteose Peptone.     

Influence of mechanical weeding and fertilisation on perennial weeds,fungal diseases,soil structure and crop yield in organic spring cereals

ABSTRACT

There is a need both in organic farming and on farms using integrated pest management for non-chemical measures that control the perennial weed flora. The effect of mechanical weeding and fertilisation on perennial weeds, fungal diseases and soil structure were evaluated in two different experiments in spring cereals. Experiment I included six strategies. The first strategy was (1) without specific measures against perennial weeds. The other strategies encompassed one or two seasonal control measures; (2) rhizome/root cutting with minimal soil disturbance in autumn, (3) hoeing with 24?cm row spacing, (4) combined hoeing and disc harrowing in autumn, (5) ‘KvikUp’ harrowing in spring, and (6) ‘KvikUp’ harrowing in spring and autumn. Experiment II included factor (i) inter-row hoeing and (ii) fertilisation level. This experiment included the comparison between normal row spacing (12?cm) with weed harrowing versus double row spacing (=24?cm) in combination with inter-row hoeing and 4 fertilisation levels (50–200?kg N ha^?1). In experiment I the strategies consisting of no or one direct weed control measure (1, 2, 3 and 5) clearly did not control the perennial weeds. The two seasonal control measures (4 and 6) gave a satisfactory weed control and highest crop yield. The combination of best weed control and no measured harmful effects on soil structure or increase of fungal diseases may explain the highest yields for these strategies. In Experiment II, hoeing and 24?cm spacing gave less perennial biomass compared to 12?cm spacing. Grain yields increased linearly with increasing nitrogen input. The study shows that both inter-row hoeing and weed harrows, are important elements in integrated pest management practice and organic farming. In addition, our results indicate that efficient mechanical weeding is possible without harmful effects in crop rotation consisting of various spring cereals as regards soil structure and plant health.     

Mammary Secretion of IgG in Sows

The IgG-concentration was determined in serum of 3 pregnant sows before and after partus and in colostrum of 7 sows 0–6 days post partum. The IgG-concentration decreased in serum before partus and increased after partus. The lowest value (1.5 g/100 ml) was observed at partus. The results indicate that IgG is transmitted from serum to colostrum.The concentration of IgG in colostrum was found to be 2.1–10.4 g/100 ml at partus. The concentration decreased very fast during the first day post partum. During 3–6 days post partum the IgG concentration was rather constant (0.3–0.5 g/100 ml). The importance of the results for the passive immunization of piglets is discussed.     

Morphological and Ultrastructural Studies of Moose Spermatozoa

Epididymal spermatozoa from moose were studied in phase contrast, light interference and electron microscope. Some samples taken from cauda were diluted and frozen in liquid N₂. The motility of the sperms after thawing was good.The concentration of spermatozoa in cauda was calculated to 10 × 10⁶ cells per µl.Morphologically the spermatozoa of moose were found to be quite similar to those collected from bulls. The length of the sperm head was found to be approx. 8.8 µ and the average maximal width 5.2 µ. The average length of the tail was 54.7 µ and the entire length of the spermatozoon varied from 60 to 64 µ. Compared with sperm cells from bulls the moose spermatozoa appeared to have a somewhat shorter and broader head and a slightly shorter tail.The migration of the cytoplasmatic droplets, which was found to be completed in caput, seemed to follow the same pattern as in bulls and boars. As found in these species there was also in the moose a higher frequency of secondary abnormalities in the spermatozoa from cauda than in those from the other parts of epididymis.Studies of the fine structure of the moose spermatozoa seemed to indicate that these are of the same type as the spermatozoa of bulls, rams and boars. In sagittal sections the sperm head was thin, but in contrast to the sperm cells of the species mentioned above no typical waist-like narrowing in the equatorial region was found. The equatorial segment also seemed to be less arched than in the spermatozoa from bulls, rams and boars. Otherwise, no principal difference was found between ultrastructure of the moose spermatozoa and that of the spermatozoa collected from domestic species.     

An Intensive Approach to Atlantic Halibut Fry Production

The larval stage is regarded to be the main bottleneck of halibut production. Halibut eggs were obtained from captive broodstock both by stripping and by natural spawning. Artificial photoperiods were used to increase the total spawning season. Yolk sac larvae are presently produced either in small stagnant units or in large flow through systems. A major consideration is to avoid stress of the larvae, caused by mechanical disturbances of the larvae and by high bacterial load or high ammonia levels in the water.
The experiments showed that halibut larvae began to ingest algae earlier than rotifers Brachionus sp. Supplementation of algae to first feeding tanks resulted in enhanced survival and growth rate of the larvae. Both rotifers and Artemia can be enriched with very high levels of highly unsaturated n-3 fatty acids (n-3 HUFA). Enriched live feed, containing high levels of n-3 HUFA and total lipids, enhanced both survival and growth of the halibut larvae. The highest growth rates were obtained with wild zooplankton and addition of algae, but enriched cultivated feed combined with algae resulted in growth of the same magnitude as with wild zooplankton.     

Effects of acidification on the concentrations of heavy metals in running waters in Sweden

Heavy metals in running water are analysed within the Swedish Surface Water Monitoring Programme at about 80 stations. Data for selected rivers and brooks has been used to assess the effect of soil acidification on the concentrations of metals in waters. In southern Sweden, acidification shows a significant effect on Zn and Cd. In the upper parts of the drainage areas, there is an marked increased leakage of these metals from soils to waters indicated by elevated concentrations of Zn and Cd in brooks and also by high maxima during periods of low pH values. The increased leaching from forest soils also influences the concentrations in rivers in southern Sweden. During periods of high water flow, the pH values of the rivers decreases and the concentrations of Zn and Cd increases. At pH levels of 6.2–6.5 the concentrations of these metals are mostly 2–5 times higher as compared to pH levels of about 7.0. Since high concentrations of Zn and Cd coincides with high water flow, the transport of these metals has most certainly increased several times compared to the pre-industrial period. Hence, the by far most important human impact on the loading of Zn and Cd on the marine areas, surrounding southern Sweden is the increased leakage of these metals due to acidification. In northern Sweden the effects of acidification on Zn and Cd are less evident. In general, the concentrations of these metals are lower and the connection between pH and these metals are much less significant in the rivers. The links between acidification and the concentrations of Pb and Cu in the watercourses are comparatively much weaker. These two metals are more related to the content of organic matter in the waters and a possible effect of acidification is overshadowed by natural transport processes in soils and waters.