Читать книгу Fundamentals of Conservation Biology - Malcolm L. Hunter Jr. - Страница 65

With a large agenda and limited resources, conservation biologists have to be efficient strategists, and this often leads them to target certain species – generically often called surrogate species or proxy species –to advance their overall goal of maintaining biodiversity (Caro 2010). Best known are the flagship species, the charismatic species that have captured the public's heart and won their support for conservation (Verissimo et al. 2011; Skibins et al. 2013). Some species have won converts to conservation across the globe; consider the cuddliness of the giant panda, the haunting songs of the humpback whale, and the grandeur of the tiger. Some species have been rallying points for local action, engendering local pride and concern. In northeastern Peru, for example, conservationists built a program around the yellow‐tailed woolly monkey, an endangered species endemic to the area, using special T‐shirts, posters, and other means. Once the local people learned how special their monkey was, it was much easier to enlist their support for conservation of all the local biota (see Case Study 15.1).

Large mammals, especially those with big brown eyes, are often the most successful flagships, but many other species have been successfully used too. In northern Maine an inconspicuous rare plant with an unprepossessing name, Furbish’s lousewort, became a flagship species for the effort that stopped a dam that would have flooded 35,000 hectares of forest. This was a case where concern for an ecosystem pushed a species into the flagship role. A better‐known example of the flagship process in reverse comes from the northwestern United States where concern for old‐growth forests made the spotted owl a flagship species.

Conservationists sometimes focus on umbrella species on the assumption that addressing the habitat needs of a particular species can, under the right circumstances, benefit the habitat of many species, even whole ecosystems, thus making the target species an umbrella for many species. For example, to secure a viable population of snow leopards you will, by extension, have to secure a large population of various species of ungulates – the snow leopard’s prey – and the large mountain and grassland areas those herbivores require to survive, and hence all the plants and smaller animals that also live in such places. Typically umbrella species are relatively large animals and thus many umbrella species are also flagship species. However, the terms are not synonymous because it is their patterns of habitat use, not popularity, that make some species good umbrellas.

Conceptually, umbrella species should have large home ranges, and thus by protecting enough habitat for their populations, adequate habitat for many other species will also be protected. Similarly, if umbrella species are found in a wide variety of ecosystems across a broad geographic range they can provide an umbrella for a very large set of species. The tiger is a classic example (Fig. 3.12). Conservationists have also used the umbrella species concept in other ways with mixed results (Roberge and Angelstam 2004; Branton and Richardson 2011), for example, by conserving habitat specialists that will only generate a small umbrella, or, conversely, by identifying suites of umbrella species to generate a broader umbrella. When using the broad umbrella species concept for such specific applications, the conservation “shortcut” might disappear if the exercise requires detailed information on the habitat needs of co‐occurring species (Seddon and Leech 2008).

Figure 3.12 With a geographic range reaching from the Russian Far East south to Indonesia and west to India (formerly to Turkey and Iran), the tiger ranges across a broad set of ecosystems – boreal forests, mangrove swamps, rain forests, dry deciduous woodlands, riparian thickets, and more. Efforts to keep the tiger from going extinct have benefitted other wild creatures throughout much of Asia thus making it a classic umbrella species.

(Martin Prochazkacz/Shutterstock and Ondrej Prosicky/Shutterstock)

Some species are useful to conservation biologists because the health of their populations is an easy‐to‐monitor indication of environmental conditions or of the status of other species; these are called indicator species (Niemi and McDonald 2004). They are the “miners’ canaries” that can warn us about general environmental degradation just as miners used to carry canaries to warn them of poor air quality. The classic example comes from the impact of DDT on peregrine falcons, brown pelicans, and some other birds. DDT caused their eggs shells to thin, resulting in fewer young produced and catastrophic declines of these species. This phenomenon first alerted scientists to a subtle but pervasive and serious impact of DDT and similar compounds for an entire ecosystem and ultimately human health. Smaller species are often sensitive indicators; for example, lichens reflect forest management practices that change a forest’s microclimate (Nascimbene et al. 2013) as well as urban air quality, and aquatic invertebrates are monitored to track water pollution (Sundermann et al. 2013). Some indicator species provide “easy access”; for example, monitoring colonial seabirds to assess the health of the marine realm is often easier than deploying oceanic survey vessels (Cury et al. 2011). Indicator species may also reflect undisturbed ecosystems that are prime candidates for reserves. If, for example, you find an area with a sizable population of curassows, chachalacas, or guans (a family of large, delicious birds that are avidly sought by hunters throughout Latin America), you can be fairly confident that it is not heavily hunted and therefore might be a relatively easy place to establish a reserve (Thiollay 2005).