Protected: Chapter 15. Saving Our Natural Capital
Chapter Summary
The most challenging problem facing humanity is the loss of biodiversity and ecosystem services. While climate disruption could theoretically be solved by limiting greenhouse gas emissions (no small task), that disruption is just one of the forces that are wiping out the millions of species and billions of populations of non-human organisms that need conservation. Even though many species share the same habitats, preserving that diversity will require huge investments.
Unfortunately, scientists often lack the ability to diagnose the cause or causes of a population’s decline or the ecological information necessary to restore a habitat when its deterioration is clearly the cause. They also often lack a good basis for determining the best choice when trade-offs are necessary, because populations and species are bound together in complex webs of relationships. But we know that many people value other organisms because they are humanity’s only known living companions in the universe (ethics) and are often beautiful and endlessly intricate and fascinating (esthetics). Perhaps most important, humanity is heavily dependent on both species and populations of other organisms because they supply us with a steady flow of indispensable services and goods. Multiple and diverse populations provide the services: if there were only one small population of spruce trees in Colorado, many homes now protected by the range of spruce populations would be subject to avalanches; if there were just one population of honeybees in Italy, many crops around the world would lack pollination. But global species diversity would not be reduced by the loss of all the other populations of spruces and bees.
The most common approach to preserving biodiversity has been to set aside “protected areas” in which efforts are made to minimize human impacts on endangered organisms and their habitats. This is especially true for species-rich areas, called “hotspots,” where reserves could have a disproportionate influence in protecting species diversity. For example, the remains of the Atlantic forests of Brazil contain some 40,000 plant species, 40 percent of which are found nowhere else—a true hotspot, where the creation of reserves is now being pressed. Other measures have included limiting harvests of exploited organisms when stocks show signs of depletion and restricting the use of toxins known to be harmful to wildlife. An outstanding example of the latter was stopping the use of an anti-inflammatory drug on cattle in South Asia when it was discovered that its presence in cattle carcasses was responsible for a catastrophic decline in populations of vultures, which play a key sanitary role in the area.
Much of the work on reserve design is based on the equilibrium theory of biogeography, originally developed to explain species diversity on islands. The theory has also been seen to work for habitat “islands” and has produced some useful estimates of extinction rates. Today much of the theoretical and practical work on reserves focuses on ways to provide extensions and corridors between them to effectively increase their size and make it easier for threatened organisms to migrate in the face of rapid climate disruption—a major enemy of attempts to preserve biodiversity. Reserves have played key roles in saving many elements of biodiversity from extinction, and marine reserves, protected from fishing, have shown great promise for restoring depleted fisheries.
But conservation biologists increasingly are focusing on strategies for protecting biodiversity that supplement terrestrial reserve systems, which (among other things) are often threatened by expanding human populations. A new subdiscipline of conservation biology, called countryside biogeography, is seeking ways to make seriously human-disturbed landscapes more hospitable to biodiversity. Work in Costa Rica has shown that if agriculture is not too intensive, farm areas can preserve a significant portion of the organisms in the tropical forests that once blanketed the area and have now been reduced to scattered fragments. In one case, it was shown that leaving small portions of a coffee farm in natural forest could greatly increase the quality and quantity of coffee harvested by providing habitat for the pollinators that enhanced the yield.
More general efforts are under way to emulate the coffee story and align financial and conservation efforts. A worldwide demonstration system is being set up by the Natural Capital Project (NatCap) to find ways to map ecosystem services and incorporate their value into land-use decisions. At the same time, recognizing the degree of alteration of ecosystems that has already occurred, projects are being carried out to restore stretches of degraded lands so that they can support more biodiversity and supply more ecosystem services. Classic examples are attempts in Costa Rica and Brazil to reestablish dry tropical forests in areas where they have been largely eliminated. At the extreme of the restoration movement is the Wildlands Project, aimed at “rewilding” much of western North America by reconnecting fragments of relatively undisturbed land to provide habitat for large animals such as bears and wolves.
The Millennium Ecosystem Assessment painted a dismal picture of the likely fate of biodiversity and the ecosystem services it supplies. There are a few bright spots in the picture, however. For instance, if NatCap can succeed, some of the tools necessary to rescue our natural capital will become available.
Key Terms
- Assisted migration (of species)
- Bush meat
- Captive breeding
- Charismatic species
- Colony collapse disorder
- Command-and-control policies
- Conservation biologists
- Conservation easements
- Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)
- Corridors (ecological)
- Countryside biogeography
- Debt-for-nature swap
- Ecoduct
- Ecological economists
- Endangered Species Act of 1973 (ESA)
- Endemic species
- Hotspots
- Individual transferable quotas (ITQs)
- Integrated pest management (IPM)
- Island biogeography
- Keystone species
- Marine reserves
- Mass extinction
- Megalinkages
- Millennium Ecosystem Assessment
- Natural Capital Project
- Reintroduction (of species)
- Reserves
- Restoration ecology
- Rewilding
- Shifting cultivation
- Umbrella species
- Wildlands Project
- “Wise use” groups
Discussion Questions
- Is protecting species diversity more or less important than protecting population diversity? Explain.
- If we tripled the size of Earth’s protected areas, how far do you think that would go toward protecting ecosystem services? Explain.
- What is CITES? What are the threats to biodiversity from the wildlife trade?
- What was the equilibrium theory of MacArthur and Wilson, and what has been its importance in thinking about conservation?
Further Study
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