Time to monitor livestock carcasses for biodiversity conservation and public health.
Law enforcement and integration of environmental issues into other policies able to affect species and ecosystems are cornerstones for the effective protection of biodiversity. We illustrate the necessity of monitoring and improving such enforcement and integration through the example of the European sanitary policies for managing livestock carcasses after the "mad cow disease" outbreak while supporting scavengers' conservation. Continuous updates of EU sanitary regulations for reconciling scavenger conservation and public health have led to actions whose implementation and monitoring rely on delineating scavenger feeding zones and estimating livestock mortality and scavenger feeding requirements (SFRs). However, the lack of clear and homogeneous criteria to calculate SFRs results in remarkable variations (e.g. of up to >450% in some regions). Although we offer a prospective approach to improve SFR calculations, we show here the high levels of uncertainty in these estimates based on the imperfect information available regarding scavengers' ecology. Synthesis and applications: The multiple socioeconomic and ecological impacts of sanitary crises such as "mad cow disease" underpin the need for high-level political commitments to guarantee public health, food security and biodiversity conservation. To effectively integrate scavenger conservation into sanitary policies, the shortfalls here detected when estimating scavenger feeding requirements should be addressed. We recommend policymakers establish systematic on-ground carcass monitoring for detecting implementation gaps (e.g. food shortages compromising scavenger conservation, potential risks of disease transmission), and to modify EU sanitary regulations accordingly. This monitoring would increase knowledge on scavenging ecology and epidemiological surveillance while enhancing cross-compliance. Lessons learned in Europe may help to integrate conservation issues into other sectorial policies worldwide.