The natural imperative for biological conservation

To contribute significantly to environmental policy of the next century, co nservationists will need to reach a consensus on their fundamental values a nd goals and to persuade society to adopt them. Resolution of the debate ov er the continued role of naturalness as a guiding concept has important imp lications for how conservation is practiced and the future of the disciplin e. I examine five aspects of naturalness in the context of biological conse rvation: (1) its utility, (2) its assessment, (3) its relation to values an d ethics, (4) alternative imperatives, and (5) implications of adopting it as a guiding concept. Naturalness can be viewed as a continuous gradient wi th completely natural and completely artificial extremes. Human actions are unnatural to the extent that they rely on technology to transform natural ecosystems. The ecological consequences of technological transformation oft en overwhelm the capacity of other biota to adapt and are a root cause of b iodiversity loss. The naturalness of most ecosystems or ecosystem alteratio ns can be assessed objectively despite imperfect knowledge if evolutionary limits and natural ranges of variability are carefully considered. Most con servationists value naturally evolved biotic elements such as genomes and c ommunities over artificial elements. This judgment, which is not shared by society at large, is based on intrinsic and instrumental values, including respect for nature and recognition that many ecosystem amenities stem from natural processes. Given the wide accessibility of ecologically destructive technology, fundamental shifts in societal values and approaches to ecosys tem alteration are needed to achieve conservation. Respect for nature must supplant the prevailing world view of human superiority. Although sometimes difficult to assess, naturalness is a more reasonable guide for conservati on than are other ecosystem features such as diversity, productivity, or ev olution, and naturalness is the foundation for several current conservation concepts such as ecological integrity and ecological restoration. Conserva tion biologists can help develop conservation practices and ethics that emp hasize the importance of natural ecosystems. Key roles include refining dis tinctions between natural and anthropogenic conditions, devising ways to us e ecosystems without losing biotic diversity, and facilitating shifts in so cietal values toward more respect for nature.