To the Editor — There is a firm commitment in Europe to integrating environmental questions across the policies of multiple sectors1. However, several pitfalls complicate the effective integration of environmental policies2, including unintended environmental side-effects and failures in coordination, compliance and enforcement. Our research has made us particularly aware of the problems of slow policy incorporation across multiple levels of governance.

Some impacts of European sectorial policies on the environment may be evident before policies are put into practice, or may appear soon after. But conflicts between policies are not always easy to predict, as illustrated by the impact of European sanitary regulations on European scavengers3. Regulations prohibiting the abandoning of livestock carcasses were implemented in 20004, and partly amended by derogations in 2009 and 20115,6, which allowed avian scavenger and carnivore species listed in Annex 2 of the European Habitats Directive to feed on dead livestock left in situ, especially in extensive farming systems. But these amendments arrived a decade too late — and in some regions have still not been implemented.

Compliance is crucial if European legislation is to be effective7. Yet the degree of compliance is influenced by the process of transposition into domestic laws. Although the EU Regulation 142/20116 is directly applicable in all member states, transposition is still a weak point in decentralized systems such as Spain, which has 17 autonomous regions — despite specific national legislation adopted in 20118 to transpose this particular European legislation6.

Spain plays a key role in the conservation of European scavenger species and hosts 90% of breeding pairs of European avian scavengers, including around 25,550 Eurasian griffon pairs, 2,100 pairs of cinereous vultures, 1,550 pairs of Egyptian vultures and 135 pairs of bearded vultures (Fig. 1). Spain is also home to Western Europe’s most important large carnivore populations, including around 2,500 wolves and 350 brown bears. Yet the Spanish autonomous regions have taken on average 2.3 years (range 0.5–5.5 years) to transpose this national legislation affecting these species and, worryingly, four autonomous regions are still to do so. The urgency with which national legislation is transposed in any particular autonomous region bears no relation to the abundance of obligate and facultative scavengers there.

Fig. 1
figure 1

Antoni Margalida

Spanish autonomous regions have been slow to adopt European regulations on livestock carcasses, posing a threat to scavenger species such as bearded and griffon vultures.

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This example illustrates the significance of temporal mismatches between the integration of policies4, the identification of unexpected environmental consequences3 and the implementation of policies to reverse them. Such temporal mismatches (12–17 years in this example) may be too long when the policies affect threatened species. Improving the legal mechanisms to speed up transpositions, particularly in decentralized systems, is needed if we are to boost the effectiveness of policies designed to conserve the planet’s biodiversity.