Читать книгу Fundamentals of Conservation Biology - Malcolm L. Hunter Jr. - Страница 61

Most of the economic values described previously involve species that serve as goods – physical objects that people can use – but there are some exceptions. When wild relatives of domestic species provide genetic information for plant and animal breeders, or when wild species give enjoyment to outdoor recreationists, they are providing services rather than goods. Other examples include the pollination services rendered to farmers by bees, bats, gnats, and other species, the aeration of soils and decomposition of organic matter by earthworms and many other organisms, and the removal of pollutants from air and water by plants and other organisms (for example, bacteria play an important role in degrading crude oil after accidental spills). Many of these services are not routinely purchased and could be described as ecological values, which we will address in subsequent sections. On the other hand, the absence of these services often has direct, easily measured economic costs; for example, farmers often have to rent beehives because wild pollinators have been decimated by insecticides, and the global value of pollination services has been estimated at $153 billion (Gallai et al. 2009).