Читать книгу Fundamentals of Conservation Biology - Malcolm L. Hunter Jr. - Страница 43

Most conservationists believe that every species has intrinsic value; that is, its value is independent of its usefulness to people, to any other species, or to the ecosystem it inhabits. In other words, every species has some importance without reference to anything but its own existence (Fig. 3.4). The concept of something having value without reference to humans is not universally accepted by philosophers (Justus et al. 2009). Still, the intrinsic value of species is widely accepted among conservationists and has been embraced in important institutions like the Convention on Biological Diversity (Uggla 2010; Vucetich et al. 2015) and the US Endangered Species Act in which (in theory at least) any species can be listed for protection, no matter how obscure.

Figure 3.4 A species' intrinsic value is independent of its relationship with any other species as depicted on the left, whereas its instrumental value depends on its importance to other species, including people. This tree fern supports an epiphytic bromeliad that contains a small pool of water, home to many invertebrates and a breeding site for frogs.

(Malcolm L. Hunter Jr., author)

Once you accept the idea of species having intrinsic value, it is relatively straightforward to decide which species merit more attention from conservationists: they are the species most threatened with extinction. As illustrated in Boxes 3.1 and 3.2, the probability of extinction is the primary consideration for assigning species to categories of conservation status. The World Conservation Union (which is still widely known as the IUCN, the initials of its former name) maintains a web‐based database that lists the species that fall into these categories, commonly called the Red List (www.iucnredlist.org). This provides the primary international standard for tracking the conservation status of various species, but there are others. For example, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) (cites.org) classifies endangered species into various appendices, Nature Serve (natureserve.org) maintains lists for the western hemisphere, and the Habitats and Birds Directives list all species of conservation concern in the European Union (https://ec.europa.eu/environment/nature). At a more local level, many national and state governments also maintain lists of species that are threatened within their borders (e.g. https://www.fws.gov/endangered). Sometimes, global categories are used at these local levels (e.g. Quayle et al. 2007), but more often different criteria are used, sometimes leading to very different outcomes (Harris et al. 2012). Most of these organizations also maintain lists of species that are not yet endangered but that are declining and need to be monitored. These have names such as “species of special concern” or “species to watch.” Being on one of these lists does not necessarily translate into conservation action. Issues such as instrumental value (covered in the next section) influence these decisions, as does simple popularity of a species with the public. In particular, it is apparent that endangered animals, especially vertebrates, get far more attention than endangered plants. For example, in the United States 57% of federally listed endangered species are plants, but they receive less than 4% of federal funding for endangered species (Balding and Williams 2016).