The Values of Ecosystems
Species cannot survive in isolation from other species; they are all part of some ecosystem. Therefore all ecosystems have value because the species they support have value. In other words, at a minimum the value of an ecosystem is the summation of the value of all its constituent organisms. This idea is simple enough, but it is not the end of the story. We must also consider the possibility that ecosystems have special attributes that make them valuable beyond the sum of species-specific values. Let us consider each of the major types of values that we evaluated from this perspective.
Whether or not ecosystems have intrinsic value independent of the intrinsic value of their constituent species is an issue that hinges on a complex and controversial question. Are ecosystems tightly connected, synergistic systems built around a set of closely coevolved species? Or are they based on a loose assemblage of species that happen to share similar habitat needs and end up interacting with one another to varying degrees because they are in the same place at the same time? To put it another way, are ecosystems analogous to supraorganisms in which different populations are closely connected, or are they just a collection of competing populations? This question has stimulated ecologists for decades (McIntosh 1980). Undoubtedly, the truth lies somewhere between the poles presented here and varies somewhat from ecosystem to ecosystem, but for our purposes it is sufficient to note that the closer ecosystems lie to the “Tightly connected” pole of the spectrum, the easier it is to acknowledge that they have intrinsic value.
If ecosystems do have intrinsic value, then conservationists need to protect some examples of each different type of ecosystem, especially those that are in danger of disappearing. Some types of ecosystems are rare because they occur only in uncommon environments. For example, cool forests and alpine areas are rare in Africa because the continent has only a few, isolated mountains tall enough to support these ecosystems. Other ecosystem types have become uncommon because of human activities. In particular, many types of forest and grassland ecosystems with fertile soils and benign climates have largely been converted to agricultural lands.
|1) Aquatic root mat community in caves of the Swan Coastal Plain|
|2) Cumberland Plain woodlands|
|3) Eastern Stirling Range montane heath and thicket|
|4) Grassy white box woodlands|
|5) Perched wetlands of the Wheatbelt region|
|6) Swamps of the Fleurieu Peninsula|
|7) Temperate highland peat swamps on sandstone|
|1) Atlantis sand fynbos|
|2) Bloemfontein dry grassland|
|3) Cape vernal pools|
|4) Ironwood dry forest|
|5) Legogote sour bushveld|
|6) Lowveld riverine forest|
|7) Swartland alluvium fynbos|
|1) Longleaf pine forests and savannas in the southeastern coastal plain|
|2) Tallgrass prairie east of the Missouri River and on mesic sites across range|
|3) Wet and mesic coastal prairies in Louisiana|
|4) Lake sand beaches in Vermont|
|5) Coastal strand in southern California|
|6) Ungrazed sagebrush steppe in the Intermountain West|
|7) Streams in the Mississippi Alluvial Plain|
Conservationists recognize the importance of protecting a representative array of ecosystems, but they have not yet developed many endangered ecosystem lists, at least ones with legal status analogous to various official endangered species lists. Political hurdles may be paramount, but the challenges of classifying ecosystems discussed above also play a role. Are the spruce-fir forests that occur on a few summits in the southern Appalachians a different type of ecosystem from the spruce–fir forests that stretch across Canada? If so, they are a very rare ecosystem; if not, they are just a peripheral variation of one of the planet’s most widespread ecosystems. Decisions like this are absolutely critical if you are trying to protect ecosystems for their intrinsic values, but they are not quite so important if your focus is on the instrumental values of ecosystems.