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7. Functions and Values of Tidal Wetlands
- University of Massachusetts Press
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211 Today tidal wetlands are universally regarded as valuable natural resources by scientists, and most North Americans probably share this view. Wetlands are the vital link between land and water, a location that endows them with many properties that support fish and wildlife and produce many services that benefit people. Tidal wetlands can be among the world’s most productive natural ecosystems. Wetlands temporarily store potentially harmful floodwaters, buffer and stabilize shorelines, help cleanse natural waters, reduce siltation in navigable waters, and yield natural products for human use and consumption, all while providing vital fish and wildlife habitat. This is a win-win situation for both people and wildlife. For these reasons, laws have been passed and policies issued in the United States and Canada to protect wetlands, or at least control their exploitation, whereas most upland habitats have not been accorded similar protection. Wetland functions and wetland values are quite different in meaning, although they are frequently used interchangeably to underscore the importance of wetlands to people (Table 7.1). Functions are activities that wetlands perform whether or not people consider them to be important. Hence, functions are value-neutral. Nonetheless, values are the direct result of people’s perspectives—their views on how good or useful something is. Values change over time, while functions do not (unless changed by natural forces or human actions). Changing Attitudes about Tidal Wetlands For natural resources, their value or the perception of their value by the masses is largely based on the nature of the society or culture and varies according to the needs of the society. Generally speaking, the closer one’s lifestyle is tied to nature, the greater the appreciation of natural resources. As the majority of a society moves away from this dependency, the less valuable the resources appear in the view of the populace—perhaps until such time as the resource becomes scarce, rare, or threatened with extinction. Despite public attitudes, natural resources in one way or another are the foundation supporting all societies. Before European colonization, Native Americans relied on natural resources for all of their needs—food, fiber, and shelter. For tribes along the coast, tidal marshes provided a wealth of food in the form of fish, shellfish, terrapins, waterfowl, and mammals ; materials for clothing and adornment; and items for trade (e.g., wampum made from the shells of quahogs and whelks) (Kraft 1986). “Middens”—piles of shells, bones, and other refuse—located in and adjacent to today’s marshes provide ample evidence of this life-supporting relationship. 7 Functions and Values of Tidal Wetlands 212 Chapter 7 Table 7.1. Major functions of tidal wetlands and some of their values Function Values Water storage Flood- and storm-damage protection, water source during dry season (freshwater wetlands), peat deposits, fish and shellfish habitat, waterfowl and waterbird habitat, recreational boating, fishing, shellfishing, waterfowl hunting, nature photography, aesthetic appreciation Nutrient retention and cycling Water-quality renovation, increases in plant productivity and aquatic productivity, decreases in eutrophication, pollutant abatement, global cycling of nitrogen, sulfur, methane, and carbon dioxide, peat deposits, carbon sequestration, greenhouse gas reduction Sediment retention Water-quality renovation, reduced sedimentation of waterways, pollution abatement (contaminant retention) Provision of substrate for plant colonization Shoreline stabilization, reduction of flood crests and water’s erosive potential, plant-biomass productivity, organic export, aquatic productivity, fish nursery grounds, bird breeding habitat, other fish and wildlife habitat, trapping, hunting, fishing, nature observation, production of timber (mangroves and tidal swamps), production of salt hay, scientific study, environmental education, nature photography, aesthetic appreciation Hunter-gatherer societies are solely dependent on natural resources and likely hold these lands in the highest regard. Native Americans had a healthy respect for what we call the environment and, perhaps better than any culture that followed, revered human kinship with nature and its wildlife. When America was first settled by Europeans , Colonists initially were as dependent as the natives were on the available natural resources. They were farmers, hunters, trappers , fishermen, and gatherers living from whatever nature could provide and they could grow. They probably held the Old World utilitarian attitude toward natural resources—they were to be used for the sole benefit of mankind. Tidal marshes provided free pastures for livestock grazing and winter fodder that helped farmers keep some livestock through the harsh New England winters. Their fledgling agrarian society depended on livestock to do labor that was not possible for people to do by hand (e.g., haul timber and remove stumps to clear forests for farmland...