Complexity

The ecological and human systems which form the coastal zone are ecologically and demographically highly complex.

The interface of land and sea is a dynamic habitat where energy, nutrients and populations of plants and animals mix and are recycled. This results in some of the most productive areas on earth characterized by complex food chains that maintain high production potential. Anecdotal evidence speaks of the historically high levels of productivity of coastal areas, especially high levels of fish stocks. There is good reason to believe that the current dismal nature of some coastal areas is primarily due to the chaotic destruction of the complex ecological networks. By reversing the overexploitation of key parts of the food chain, which are often commercially valuable predatory species, the ecological balance can be restored.

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Flow is an important part of the complexity of the marine and estuarine habitats. The complexity and flow of coastal resources and coastal communities make assessment or information gathering by outsiders a difficult task.

It is hard to observe resources that are: mobile, underwater, change seasonally and move between different habitats.

Such movement is often predictable on a seasonal, monthly or daily cycle but knowledge of the exact location or size of fish stocks is not easily obtained although local knowledge may be available. However, if the ecology has changed through overexploitation or habitat degradation, traditional ecological knowledge may no longer be relevant, or young, active fishers may not have experienced the richness of the habitat prior to its devastation. One option is to seek information from older residents but it is difficult to cross check such information. Fish catches many years ago occurred under very different market conditions and it may not be possible to obtain a good estimate of the potential yield of the resources even if the habitat is restored. Furthermore, if those active in fishery have recently moved to the area, their depth of knowledge of the local ecology may be limiting.

There is less isolation of marine ecosystems than one finds on land even when the marine habitats differ in appearance. The aquatic medium connecting different places in the sea is itself habitat and provides connectivity among distant locations. Many species spend different life cycle stages in very different habitats and fish move along the three dimensions of the sea.

Although they may be physically distinct, ecosystems such as coral reefs, mangroves and marshes are highly interactive with surrounding marine habitats. Outsiders may view the coastal ecosystem in separate units and not appreciate the level of interaction among them.

The ecological links between land and sea are tremendously important. Aside from the flow of people, possibly the most important connection, is the flow of water and silt from rivers to the estuaries and coastal areas. Under natural conditions in the uplands, this flow of nutrients would maintain a healthy coastal ecosystem. However, degradation of uplands, primarily due to deforestation, causes increased erosion and siltation, resulting in degradation of coastal ecosystems. Further impacts from the land come in the form of water pollution from cities and intensive farm lands.

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