656 research outputs found

    Connectivity and ecological networks : Technical Information Note 01/2016

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    This Information Note introduces connectivity and ecological networks within the context of landscape planning, design and management and should assist discussions members typically hold with professional ecologists

    Alterations in microbial community composition with increasing fCO2: a mesocosm study in the eastern Baltic Sea

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    Ocean acidification resulting from the uptake of anthropogenic carbon dioxide (CO<sub>2</sub>) by the ocean is considered a major threat to marine ecosystems. Here we examined the effects of ocean acidification on microbial community dynamics in the eastern Baltic Sea during the summer of 2012 when inorganic nitrogen and phosphorus were strongly depleted. Large-volume in situ mesocosms were employed to mimic present, future and far future CO<sub>2</sub> scenarios. All six groups of phytoplankton enumerated by flow cytometry ( &lt;  20 µm cell diameter) showed distinct trends in net growth and abundance with CO<sub>2</sub> enrichment. The picoeukaryotic phytoplankton groups Pico-I and Pico-II displayed enhanced abundances, whilst Pico-III, <i>Synechococcus</i> and the nanoeukaryotic phytoplankton groups were negatively affected by elevated fugacity of CO<sub>2</sub> (<i>f</i>CO<sub>2</sub>). Specifically, the numerically dominant eukaryote, Pico-I, demonstrated increases in gross growth rate with increasing <i>f</i>CO<sub>2</sub> sufficient to double its abundance. The dynamics of the prokaryote community closely followed trends in total algal biomass despite differential effects of <i>f</i>CO<sub>2</sub> on algal groups. Similarly, viral abundances corresponded to prokaryotic host population dynamics. Viral lysis and grazing were both important in controlling microbial abundances. Overall our results point to a shift, with increasing <i>f</i>CO<sub>2</sub>, towards a more regenerative system with production dominated by small picoeukaryotic phytoplankton.</p

    Livestock disease management for trading across different regulatory regimes

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    The maintenance of livestock health depends on the combined actions of many different actors, both within and across different regulatory frameworks. Prior work recognised that private risk management choices have the ability to reduce the spread of infection to trading partners. We evaluate the efficiency of farmers' alternative biosecurity choices in terms of their own-benefits from unilateral strategies and quantify the impact they may have in filtering the disease externality of trade. We use bovine viral diarrhoea (BVD) in England and Scotland as a case study, since this provides an example of a situation where contrasting strategies for BVD management occur between selling and purchasing farms. We use an agent-based bioeconomic model to assess the payoff dependence of farmers connected by trade but using different BVD management strategies. We compare three disease management actions: test-cull, test-cull with vaccination and vaccination alone. For a two-farm trading situation, all actions carried out by the selling farm provide substantial benefits to the purchasing farm in terms of disease avoided, with the greatest benefit resulting from test-culling with vaccination on the selling farm. Likewise, unilateral disease strategies by purchasers can be effective in reducing disease risks created through trade. We conclude that regulation needs to balance the trade-off between private gains from those bearing the disease management costs and the positive spillover effects on others
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