Priorities in Conservation
Given that some species and genes are sure to be lost and some natural habitats converted to other land uses in the coming decades, how should scarce human and financial resources be spent to minimize biotic impoverishment and maximize biodiversity’s contribution to human well-being? How can the most useful components of biodiversity be saved for current or future use? And how can such ethical considerations as our responsibility to other species and to future generations be incorporated into conservation priorities?
Clearly, these questions cannot be answered with scientific information on the nature, distribution, and status of biodiversity alone. Such factors as awareness of the problem and its solutions, perceived trade-offs with other basic human needs, and local political considerations will all influence conservation priorities.
Distinctiveness: Numbers Aren’t Everything.
To conserve the widest variety of the world’s life forms and the complexes in which they occur, the more distinctive elements of this diversity should receive high priority. For example, preserving an assemblage of plants and animals is comparatively more important if those species are found nowhere else or are not included in protected areas. Similarly, if the choice is between conserving a species with many close relatives or a species with few, the more distinctive species should be saved.
Maintaining the highest number of species without considering their taxonomic position makes little sense, as a comparison of marine and terrestrial environments shows. Terrestrial environments contain at least 80 percent of the world’s total species, mainly because vascular plants and insects are so numerous on land–accounting for nearly 72 percent of all described species in the world–and so poorly represented in marine environments. However, the sea contains greater proportions of higher taxonomic units. Marine ecosystems contain representatives of some 43 phyla while terrestrial environments are home to only 28 phyla. The sea contains fully 90 percent of all classes and phyla of animals. Clearly efforts to conserve the widest array of biodiversity must give attention to all levels of the taxonomic hierarchy.
Utility: Global or Local, Current or Future?
To some extent, utility is always a criterion in setting biodiversity priorities. Nobody opposed the extinction of wild populations of the smallpox virus, and most people would agree that it’s more important to conserve a subspecies of rice than a subspecies of “weed.” Similarly, maintaining forest cover in the watershed above a village or irrigation project seems more important than preserving a similar forest in a region where increased flooding or soil erosion would not affect human activities downstream.
Of course, many decisions about which species to save are much more difficult than the one governing smallpox’s fate. In general, questions about the usefulness of species, genes, or ecosystems can be complicated by two factors. One is the issue of inter-generational equity–whether today’s needs outweigh those of future generations. It seems reasonable enough to expect future generations to value the species most valued today, but it is impossible to predict humanity’s exact needs, and many other species of unknown value today are sure to become more important in the future. Amid attempts to conserve species prized today, some value has to be assigned to future generations’ needs.
Second, we must ask the question: “Utility for whom?” Biodiversity has obvious values to local communities, nations, and the entire world, but the benefit is not identical for each group. From a global perspective, the conservation of a region’s biodiversity might help to regulate climate, influence the atmosphere’s chemical composition, and provide all of humanity with industrial products, medicines, and a source of genes for crop breeding. Locally, conservation may also provide people with fuel, clean water, game, timber, aesthetic satisfaction, and important cultural symbols or resources.
Because the conservation benefits received by the local and global communities are not congruent, international and local priorities will also differ. To humanity at large, conserving tropical forests matters more than conserving semi-arid deserts since the forests contain a tremendous variety of life and heavily influence global climate. Locally, however, each region’s biodiversity is equally valuable since it provides essential ecosystem services that local people rely upon. Neither perspective is necessarily the “correct” view of biodiversity; either–global or local, current or future–reflects an implicit value judgment.
Threat: Saving the Most Beleaguered Species and Ecosystems First.
In general, the threat to biological diversity is influenced by how widespread species are, how common they are over their range, and by such human pressures as harvesting, land conversion, and environmental pollution. The threats to species vary dramatically by region, and in each region some ecosystems are more threatened than others. For instance, Central America’s tropical rainforests are less threatened than the remaining fragments of tropical dry forest in that region. In such cases, the dry forests should receive the most attention even though the rainforests contain more species.
These three factors–distinctiveness, utility, and threat–help make value judgments more explicit as conservation priorities are set. If a strictly global perspective is adopted, then preserving the most species-rich sites in the world seems most important. Indeed, this global perspective has led some organizations to focus on conservation in the “megadiversity” countries–Brazil, Colombia, Indonesia, Madagascar, Mexico, Zaire and others. In contrast, from a nationalist perspective, each country’s biodiversity is worth roughly what every other country’s is. Similarly, if today’s needs for genes, species, or ecosystems are considered paramount, tomorrow’s needs can’t be too.
