According to the Ramsar convention of 1971, wetlands are areas of fen, marsh or peat land or water whether natural or artificial, permanent or seasonal, with water flowing or static, fresh, brackish or salty, including marine waters of depth at low tides not exceeding six metres.
Wetland ecosystems account for about 6% of the global land area and perform various functions vital to all of us. Wetland functions are defined as a process or series of processes that take place within a wetland.
Functions that provide internal values are the functions that maintain or sustain the wetland and are essential to the continued existence of the wetland.
Conversely, many functions have external values that extend beyond the wetland itself. On a local scale, wetlands affect adjacent or nearby ecosystems, for example, by reducing flooding in downstream communities or by removing nutrients from wastewater, and in habiting biological species. However, the broadest influence of wetland functions is global.
Wetlands as habitats for biological species
Wetland functions can be grouped broadly as habitat, hydrologic, or water quality.
They include the storage of water, transformation of nutrients, growth of living matter, and diversity of wetland plants, and they have value for the wetland itself, for surrounding ecosystems, and for people.
However, not all wetlands perform all functions nor do they perform all functions equally well. The location and size of a wetland may determine what functions it will perform its functions.
Also other factors like climatic conditions, quantity and quality of water entering the wetland, and disturbances or alteration within the wetland or the surrounding ecosystem.
Wetlands are now thought to have a significant effect on air quality, which is influenced by the nitrogen, sulfur, methane, and carbon cycles.
In addition, migrating birds are dependent upon wetlands as they travel. They provide food, water, and shelter for fish, shellfish, birds, and mammals, and they serve as a breeding ground and nursery for numerous species.
Many endangered plant and animal species are dependent on wetland habitats for their survival. (See the article “Wetlands as Bird Habitat” in this volume.
. “While wetland functions are natural processes of wetlands that continue regardless of their perceived value to humans, the value people place on those functions in many cases is the primary factor determining whether a wetland remains intact or is converted for some other use” (National Audubon Society, 1993).
It is unfortunate that, even with all the above functions, wetlands every where are being lost or altered because of the disruptions in their natural flow, and in most areas wetland loss has reached critical proportions with resource exploitation surpassing the appropriate providing capacity.
Wetland disturbances may be the result of natural conditions, such as an extended drought, or human activities, such as land clearing, dredging, or the introduction of nonnative species.
Wetland loss within and even around Rwanda is mainly due to selfish consumptive interests of the people. In a chaotic situation, especially during wartime, everybody tried to get his personal advantage, without thinking about others or future.
Besides, the Rwandan civil war (1994) happened in a particularly fragile environment not only in terms of it being a highly populated area, but also biodiversity.
During the war, important losses were registered in Rwanda in terms of the environment (habitat destruction, pollution and wildlife), and the consequences will be felt over the long term.
The war bombs killed all life forms, the water quality was affected, mainly due to corpses being thrown into rivers, and this even affected the entire Nile basin and its biodiversity.
Because the economic value of wetlands can not easily be determined, there is limited appreciation of their realistic value to justify their conservation especially to the local users who even happen to be the closest and direct users.
Therefore assessing each function of a wetland and then assigning a value to each function is a step toward the protection of sensitive wetlands.
Furthermore, an evaluation system that provides the basis for comparing wetlands would facilitate mitigation for unavoidable wetland losses, would provide a tool for determining the success (or failure) of programs and policies intended to protect or manage wetland resources, and would assist in identifying long-term trends in the condition of wetland resources.
The evaluation if based on functions and values in terms of wetland effectiveness to perform a particular function, opportunity or the potential for a wetland to perform a specific function, social significance value of a wetland in terms of special designations (does it have endangered species?), potential economic value (is it used regularly for recreational activities?), and strategic location (is it in a State where very few wetlands of its type remain?), and habitat suitability is more suitable and this can be based on “predictors” that relate to the physical, chemical, and biological characteristics of the function being evaluated can be used.
If any hope remains for preserving the Nations wetland resources, it depends upon obtaining public support. Public support can be won if scientists can explain clearly how wetlands function, how they interact with their surroundings, and how their functions can benefit society.
Wetlands have come under intensive scientific study only during the last two decades. Techniques of wetland evaluation will improve as scientists gather more information about the processes that take place in wetlands and about the similarities and differences among the functions of different types of wetlands.
In order to protect wetlands, the public first must recognize the values of wetlands. People need to understand what is lost when a wetland is changed into an agricultural field, a parking lot, a dump, or a housing development.
Understanding the functions of wetlands will make it easier to evaluate wetlands when other uses are considered.
In order to develop public support and to encourage enlightened policy decisions and regulations, it is critical to create and maintain a data base of wetland characteristics in which the data are reliable, comparable, and repeatable at periodic intervals in order to monitor long-term trends.