Jellyfish jelly press and jelly perception

Since the early 2000’s, invasions and blooms of jellyfish have been increasingly reported in scientific literature as well as in the general media. Despite this increased coverage, the global jellification issue remains unsolved due to the scarcity of extended time series. The aim of this study was to determine to what extent the main messages about jellyfish (increase, causes, threats, solutions, etc.) in the Flemish (Belgian Dutch-language) media correspond with the knowledge and perception of recreational users, tourism-related professionals and local government officials on the Belgian coast. The number of articles in the Flemish media (140) increased from <5 in 2000 to 27 in 2010, with half of them reporting on jellyfish in the Belgian Part of the North Sea. Almost 75 % of these articles reported on the causes (overfishing being mentioned as the main cause) and economic consequences of jellyfish blooms. Articles about the dramatic consequences of stinging, poisonous and non-indigenous species were also common. A questionnaire-based survey carried out on the Belgian coast in summer 2012 indicated that jelly perception is only partly driven by the general media, while personal experience seemed at least equally important as driver. Information on causes, threats, consequences and solutions for problems caused by jellyfish corresponded to a large extent with the answers given by recreational users and tourism-related professionals. Respondents generally agreed that all underlying causes of a potential jellification problem should be addressed and tackled at an international level. With keywords like “pain”, “smell” and “slime” used to describe jellyfish, they have little sympathy from most actors, and most recreational users of beaches and coastal waters are extremely careful with any type of jellyfish, especially when children are involved. Species-specific knowledge (names, ecology, stinging vs. harmless species) presented in the media is not assimilated by most recreational users or local officials, except for divers, who have a very different perception of jellyfish than most recreational users. This lack of knowledge appeared to be a key issue in perception among recreational users. As public perception is a key driver in policy decisions, integrated coastal zone management and measures should provide good and easily understandable information, for example by distributing leaflets and putting up warning signs on the beach. This will result in a better understanding and acceptance of jellyfish as well as generating high-quality data from citizen science programs. Better and more information on jellyfish will thus benefit all the actors and sectors potentially affected by jellification.     

Network structure and parasite transmission in a group living lizard,the gidgee skink, <Emphasis Type="Italic">Egernia stokesii</Emphasis>

Gidgee skinks (Egernia stokesii) form large social aggregations in rocky outcrops across the Flinders Ranges in South Australia. Group members share refuges (rock crevices), which may promote parasite transmission. We measured connectivity of individuals in networks constructed from patterns of common crevice use and observed patterns of parasitism by three blood parasites (Hemolivia, Schellackia and Plasmodium) and an ectoparasitic tick (Amblyomma vikirri). Data came from a 1-year mark-recapture study of four populations. Transmission networks were constructed to represent possible transmission pathways among lizards. Two lizards that used the same refuge within an estimated transmission period were considered connected in the transmission network. An edge was placed between them, directed towards the individual that occupied the crevice last. Social networks, a sub-set of same-day only associations, were small and highly fragmented compared with transmission networks, suggesting that non-synchronous crevice use leads to more transmission opportunities than direct social association. In transmission networks, lizards infested by ticks were connected to more other tick-infested lizards than uninfected lizards. Lizards infected by ticks and carrying multiple blood parasite infections were in more connected positions in the network than lizards without ticks or with one or no blood parasites. Our findings suggest higher levels of network connectivity may increase the risk of becoming infected or that parasites influence lizard behaviour and consequently their position in the network. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users. This contribution is part of the special issue “Social Networks: new perspectives” (Guest Editors: J. Krause, D. Lusseau and R. James).     

Biological and chemical assessments of zinc ageing in field soils

As zinc (Zn) is both an essential trace element and potential toxicant, the effects of Zn fixation in soil are of practical significance. Soil samples from four field sites amended with ZnSO₄ were used to investigate ageing of soluble Zn under field conditions over a 2-year period. Lability of Zn measured using ⁶⁵Zn radioisotope dilution showed a significant decrease over time and hence evidence of Zn fixation in three of the four soils. However, 0.01 M CaCl₂ extractions and toxicity measurements using a genetically modified lux-marked bacterial biosensor did not indicate a decrease in soluble/bioavailable Zn over time. This was attributed to the strong regulatory effect of abiotic properties such as pH on these latter measurements. These results also showed that Zn ageing occurred immediately after Zn spiking, emphasising the need to incubate freshly spiked soils before ecotoxicity assessments.     

Social and ecological facets of pest management in Honduran subsistence agriculture: implications for IPM extension and natural resource management

In subsistence farming systems of the developing world, adoption of resource-conserving practices such as integrated pest management (IPM) is often strikingly low. This has partially been ascribed to researchers’ limited understanding of how technologies develop at the interface of the systems’ social and ecological components. In Honduras (Central America), there exists concern about limited adoption and diffusion of IPM technologies in certain smallholder production systems. In this study, we determine social and ecological drivers of IPM adoption in subsistence maize production in the country’s hillside environment. Honduran small-scale maize production is typified by a key insect pest (the fall armyworm, Spodoptera frugiperda) being partly kept at bay through action of a diverse natural enemy complex, including ants, social wasps, carabid beetles, and spiders. Local agricultural landscapes, primarily shaped through shifting cultivation, provide key resources to maintain this natural enemy diversity. These local ecological conditions and related natural enemy abundance strongly influence farmers’ agroecological knowledge and pest management practices. In the meantime, farmer practices are also affected by local communication networks, which help validate and spread IPM concepts and technologies. Based on our findings, we advocate a holistic approach to improve IPM extension through mapping of agroecological opportunities, visualization of regional patterns in farmer knowledge, and associated priority setting. Local IPM capacity could be built through institutional strengthening and adaptive comanagement, while IPM training should be linked with natural resource management initiatives. These approaches may eventually improve the way IPM is delivered to small-scale farmers who operate in the ecologically diverse environments of the tropics.     

Comparison of forest edge effects on throughfall deposition in different forest types

This study examined the influence of distance to the forest edge, forest type, and time on Cl⁻, SO₄²⁻, NO₃⁻, and NH₄⁺ throughfall deposition in forest edges. The forests were dominated by pedunculate oak, silver birch, or Corsican/Austrian pine, and were situated in two regions of Flanders (Belgium). Along transects, throughfall deposition was monitored at distances of 0-128 m from the forest edge. A repeated-measures analysis demonstrated that time, forest type, and distance to the forest edge significantly influenced throughfall deposition of the ions studied. The effect of distance to the forest edge depended significantly on forest type in the deposition of Cl⁻, SO₄²⁻, and NO₃⁻: the edge effect was significantly greater in pine stands than in deciduous birch and oak stands. This finding supports the possibility of converting pine plantations into oak or birch forests in order to mitigate the input of nitrogen and potentially acidifying deposition.     

Occurrence of Human Enteric Viruses in Commercial Mussels at Retail Level in Three European Countries

In this study, the prevalence of different enteric viruses in commercial mussels was evaluated at the retail level in three European countries (Finland, Greece and Spain). A total of 153 mussel samples from different origins were analysed for human norovirus (NoV) genogroups I and II, hepatitis A virus (HAV) and hepatitis E virus (HEV). Human adenovirus (HAdV) was also tested as an indicator of human faecal contamination. A full set of controls (such as sample process control, internal amplification controls, and positive and negative controls) were implemented during the process. The use of a sample process control allowed us to calculate the efficiencies of extraction, which ranged from 79 to 0.5?%, with an average value of 10?%. Samples were positive in 41?% of cases, with HAdV being the most prevalent virus detected (36?%), but no significant correlation was found between the presence of HAdV and human NoV, HAV and HEV. The prevalences of human norovirus genogroup II, HEV and human NoV genogroup I were 16, 3 and 0.7?%, respectively, and HAV was not detected. The estimated number of PCR detectable units varied between 24 and 1.4?×?10³?g^?1 of digestive tract. Interestingly, there appeared to be a significant association between the type of mussel species (M. galloprovincialis) and the positive result of samples, although a complete overlap between country and species examined required this finding to be confirmed including samples of both species from all possible countries of origin.     

Land Management in the American Southwest: A State-and-Transition Approach to Ecosystem Complexity

State-and-transition models are increasingly being used to guide rangeland management. These models provide a relatively simple, management-oriented way to classify land condition (state) and to describe the factors that might cause a shift to another state (a transition). There are many formulations of state-and-transition models in the literature. The version we endorse does not adhere to any particular generalities about ecosystem dynamics, but it includes consideration of several kinds of dynamics and management response to them. In contrast to previous uses of state-and-transition models, we propose that models can, at present, be most effectively used to specify and qualitatively compare the relative benefits and potential risks of different management actions (e.g., fire and grazing) and other factors (e.g., invasive species and climate change) on specified areas of land. High spatial and temporal variability and complex interactions preclude the meaningful use of general quantitative models. Forecasts can be made on a case-by-case basis by interpreting qualitative and quantitative indicators, historical data, and spatially structured monitoring data based on conceptual models. We illustrate how science- based conceptual models are created using several rangeland examples that vary in complexity. In doing so, we illustrate the implications of designating plant communities and states in models, accounting for varying scales of pattern in vegetation and soils, interpreting the presence of plant communities on different soils and dealing with our uncertainty about how those communities were assembled and how they will change in the future. We conclude with observations about how models have helped to improve management decision-making.     

Dialdehyde starch and zein plastic: Mechanical properties and biodegradability

Dialdehyde starch (DAS) and zein, a hydrophobic corn protein, were investigated to produce biodegradable plastics with improved water resistance and mechanical properties. In the study, dialdehyde starch and zein ratio, plasticizers, and degree of starch oxidation were examined. Increased molding temperature and level of starch oxidation decreased water absorption of the plastic. Tensile strength and Young's modulus increased with starch oxidation. The biodegradation of starting materials and ground plastic specimens was studied in aerobic soil reactors maintained at 25°C for 180 days. Biodegradation of corn starch, zein, and dialdehyde starch for 180 days produced CO₂ equivalent to 64, 63, and 10% of theoretical carbon, respectively. Specimens of molded DAS and zein (3 : 1) plastic showed accelerated CO₂ evolution compared to DAS and other raw materials alone. By 180 days, specimens made with starch of low oxidation (1 and 5% oxidized) demonstrated a 60% biodegradation, and specimens with highly oxidized starch (90% oxidized) achieved 37% biodegradation.Paper presented at the Bio/Environmentally Degradable Polymer Society—Third National Meeting, June 6–8, 1994, Boston, Massachusetts.Journal Paper J-15927 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Project No. 3258.