[Environmental protection: ethical and scientific sources of tension].

Environmental ethic is complex, dynamic, and related to cultural contexts that are neither given once and for all, nor valid for all people. Yet, the current biodiversity crisis tends to be followed by the spread of universal values related to nature and its protection. Far from standardizing the pluralism of these values, this universal trend leads to two major tensions in the field of nature conservation. The first concerns the scientific or epistemic values: nature or "biodiversity" is altogether being reduced in sub-categories or by contrast considered as a complex object by modern ecological science. Biodiversity is indeed both increasingly considered in terms of its complexity and unpredictability, or on the contrary, as a collection of natural objects that can and must be managed with easily quantifiable indicators. The second tension concerns ethical values. These values tend to be reduced and simplified in equating nature with "services" that can benefit human societies. But this utilitarian reduction also hides a diversification of ethical values. This article aims to analyze what characterizes this contemporary ethical and scientific floating with respect to the values involved in the protection of nature.