Does proactive biodiversity conservation save costs?

Ecologists usually argue for a proactive approach to species conservation-it should start before a species is endangered and under substantial risk of extinction. In reality, however, conservation often only starts when species populations are already in a critical state. This may be the result of a policy process in which those actors who see only little or no benefits from conserving species try to delay conservation as long as possible to avoid its cost. A frequent consequence is that populations decline to critical levels so that once conservation policies set in due to legal obligations, political pressure or any other reason, additional conservation measures are required to re-establish the populations. We show that the costs associated with this policy process may be higher than those of a proactive policy. This is somewhat surprising because the costs of maintaining populations at a level at which they are not endangered may occur over a longer period. However, the costs of bringing species populations back to those levels may be so high that they outweigh the costs of the proactive approach. We develop simple cost functions that capture the main economic and ecological parameters relevant to our argument and apply them for an assessment of the costs of common hamster (Cricetus cricetus) conservation in the region of Mannheim, Germany. We find that a proactive approach would have saved between a,not sign17.2 and a,not sign36.4 mn compared to the existing policy where conservation was delayed until legal requirements forced local policy makers to implement a comprehensive hamster protection programme.