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We discuss a diversity measure combining information of relative abundances and taxonomic distinctiveness suggested by Ricotta (2004). We show that Ricotta's measure violates weak species monotonicity, a condition that requires that the addition of a species should always increase a diversity index if abundances change only marginally. We suggest an alternative index satisfying weak species monotonicity and apply it to the 'Zeesserveld' forest reserve in the Netherlands.

The EU Marine Strategy Directive (MSD) has a regional focus in its implementation. The directive obliges countries to take multiple uses and the marine strategies of neighboring countries into account when formulating marine strategies and when designating marine protected areas (MPAs). We use game theoretical analysis both to find the optimal size of MPAs with multiple uses by multiple countries and to investigate the influences of multiple uses on cooperation. To this end, we develop a model in which two specific uses, fisheries and nature conservation, by multiple countries are considered in a strategic framework. The results of the paper suggest that EU marine policy such as the MSD and the coming Maritime Policy may help to secure the highest possible benefits from these MPAs if these policies induce cooperation among countries, but only if policies force countries to consider all possible benefits of MPAs. In fact cooperation on a single issue may give a worse outcome than the noncooperative equilibrium. The results also indicate that cooperation may be hard to achieve because of defector incentives, and therefore policy measures should be strict in enforcing cooperation on all possible uses of MPAs.

We estimate the perceived costs of legal requirements (‘coexistence measures’) for growing genetically modified (GM) Bt maize in Germany using a choice experiment. The costs of the evaluated ex‐ante and ex‐post coexistence measures range from zero to more than €300 per measure and most are greater than the extra revenue the farmers in our survey expect from growing Bt maize or than estimates in the literature. The cost estimates for temporal separation, the highest in our evaluation, imply that the exclusion of this measure in Germany is justified. The costliest measures of the ones that are currently applied in Germany are joint and strict liability for all damages. Our results further show that neighbours do not cause a problem and opportunities for reducing costs through agreements with them exist. Finally, we find that farmers’ attitudes towards GM crops affect the probability of adoption of Bt maize. Our results imply that strict liability will deter the cultivation of Bt maize in Germany unless liability issues can be addressed through other means, for example, through neighbours agreements.

Summary We describe the maize supply chain in Portugal for maize bread, a traditional bread type. As this bread is not labelled as ‘contains genetically modified organisms’ it should not contain more than 0.9 per cent genetically modified ingredients. On the basis of interviews we identify a general lack of documentation of the presence or absence of genetically modified ingredients along the complete supply chain (farmers, traders, mills and bakeries). Part of this deficiency is probably driven by a lack of awareness of the labelling rules at the end of the supply chain. A test of maize bread showed that more than 40 per cent of breads were indeed over the labelling threshold, and should be labelled. This includes GM maize that is not cultivated in the EU and enters the supply chain via international trade. We conclude that the realisation of coexistence and segregation requires involvement of the full supply chain, rather than just segregation at the start, if bread is to be sold with a GMO content below the 0.9 per cent threshold level. Alternatively, retailers can label their bread. This might be a cheaper solution and as a study from Switzerland shows may not result in adverse consumer reaction.