Dr. Whinny Larson recognizes that convincing citizens with little or no ecological training that areas traditionally treated as wastelands and dumps should be preserved is an uphill battle. Now in her 80s, Larson has witnessed and documented a number of critical changes, both encouraging and discouraging, in the ecology of Lake Erie and the surrounding watersheds. One of the most dramatic and troublesome changes has been the steady decline in Ohio's native wetlands to the point that only 10% remain. Further loss is simply unacceptable. If she can somehow present her arguments in a way that addresses the long-term economic viability of the region, she feels she has a chance of swaying the decision.
During the late 1960s and early '70s Dr. Larson had been part of the team that negotiated the Great Lakes Agreements and the first Clean Water Act. This national, regional, and local legislation did a good job of reducing point-source pollution —wastewater treatment facilities were built and the discharge of industrial toxins was reduced substantially. Indeed, by the 1990s, Larson and others had documented dramatic improvements in the water quality of Lake Erie. However, going from severely polluted to moderately polluted was not good enough—further reductions were sorely needed in order to stimulate more complete ecological recovery. This further progress would require that the harder nut be cracked—"non-point source pollution" that enters over broad areas of land. This is where wetlands come into play.
A growing body of scientific research indicates that wetlands, areas of land that are submerged by water for all or part of the year, play a key role in pollution abatement. When speaking to lay audiences, Larson often describes wetlands as the "kidneys" of the landscape in the sense that their biogeochemical activity naturally purifies the water that flows through them. Furthermore, she is quick to point out that wetlands harbor a variety of endangered plant and animal species. Larson feels frustrated by the fact that environmental activists get caught up in preserving the spectacular species of the tropical rainforest while remaining largely ignorant of the dramatic loss in biodiversity brought about by habitat destruction occurring in their own backyards. She recently inventoried the airport site and found that while it contains a mixture of typical wetland vegetation including cattail, phragmites, sedges and button-bush, it also harbors a number of species on the Federal endangered species list, including the blunt mountain-mint. Experimental evidence continues to accumulate that biodiversity is linked to ecological function—like the rivets holding the wings on an airplane, you can remove species, functional groups or ecosystems one by one without noticing an effect, but at some point the results may be catastrophic.
Over the long term, Larson feels that the survival and quality of life possible for the human species are inextricably linked with preserving biodiversity at all scales. That means preserving genetic diversity of individual species, diversity of organisms within ecosystems, diversity of ecosystems within a landscape and diversity of biomes on Earth. On the regional scale, a case can certainly be made that wetlands serve an important economic function. Indeed, a number of Larson's colleagues have quantified the economic values of wetlands.[1] They have found, for instance, that an acre of wetland can be worth tens of thousands of dollars per year in terms of its role in flood control, reduced erosion, and improved water quality.
As far as Larson is concerned, the scientific validity of wetland "mitigation" is still open to debate. On one hand, she has visited constructed wetlands and been impressed by the numerous species of birds present. On the other hand, she firmly believes that constructed wetlands can never really take the place of those destroyed. In support of this position, Larson's colleague, Joy Zedler, recently published a paper indicating that even 10 years after mitigation, some constructed wetlands fail to exhibit critical functions of the natural marshes that were destroyed, such as habitat for endangered species.[2] Furthermore, the National Academy of Sciences reviewed hundreds of replacement wetland projects and found that some were never started, some were never completed, and others failed to provide the benefits of natural wetlands.[3] The study revealed that the Army Corps fails to adequately track compliance, and when it does, it finds that compliance is poor. In Larson's view, by all means society should experiment with building and restoring wetlands, but not at the expense of the few remaining intact native wetlands!
[1] R. Costanza, R d'Arge, R. de Groot et al. 1997. The value of the world's ecosystem services and natural capital. Nature 387:253-259.
[2] J. Zedler and J.C. Callaway. 1999. Tracking wetland restoration: Do mitigation sites follow desired trajectories? Restoration Ecology 7:69-73.
[3] National Academy of Sciences Committee on Mitigating Wetland Losses. 2001. Compensating for wetland losses under the Clean Water Act. National Academy Press, Washington DC.
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