Introduction
An urban ecosystem is the trees, shrubs, soils, water, animals, that make up our cities. The natural environment is mixed with the built form infrastructure. The natural environment provides the plant and animal community with a multitude of benefits. These benefits, if converted into financial benefit have a value. This urban ecosystem is however, under tremedous pressure due to pollution. Wetlands are a crucial part of the ecosystem and form a dynamic, highly productive and valuable interface between land and water. Wetlands are among the most productive ecosystems providing unique habitats for a wide variety of flora and fauna. Wetlands provide wide range of functions, including food chain support, flood control, shoreline stabilization, sediment, nutrient and toxicant retention.

Definition
The characteristics and functions of each type of wetland is unique. Wetlands range from areas that are infrequently flooded to those that are constantly flooded with deep water. Individual wetlands also have unique soil conditions as well as particular composition of hydrophytic plant species. These characteristics have been incorporated into the following widely cited definition (Cowardin et al. 1979) :

"Wetlands are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface of the land is covered by shallow water. Wetlands can be divided into broad catagories tidal and nontidal. Its functions refer to chemical, biological or physical processes or attributes that are crucial to the integrity and stability of a wetland ecosystem."

Similarly, Government of India has adopted the definition of wetlands given by the convention on wtland of international importance (Ramsar) according to which "Wetland consists of areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or saltish including areas of marine water, the depth of which at low tide does not exceed six metres."

Wetlands in MMR
Greater Mumbai island, which has the largest coastline in the Mumbai Metropolitan Region, owes much of its present state to existance of large wetlands, spanning over three centuries. Its typical geography, i.e. a narrow wedge-shaped landmass surrounded by sea on three sides, and the reclamation of the area between 7 islands (through which Mumbai island was formed), makes it impossible to avoid infringment on the wetlands in the process of its development. The geography of Mumbai Metropolitan Region, shows that creeks originate from the point where the river reaches its senile stage and starts salination. The entire north-south coastline along the mainland have small inlets of creeks, the main ones being Versova, Manori and Vasai creeks, besides the larger Thane, Vasai, Panvel and Dharamtar creeks. Loss of wetlands in these creeks on account of reclamation, their contamination through dumping of solid waste and proliferation of slums, and destruction of mangroves, are the critical problems related to wetlands in this Mumbai Metropolitan Region. Similarly, the areas around Vasai-Virar, Navi Mumbai and southern parts of MMR also have large tracts of wetland cover.

As our understanding of the importance of wetlands expand, so do the number and scope of central and state laws to protect them. So far, the laws have generally attempted to restrict certain activities that may destroy wetlands with the Coastal Zone Management Act and The Central Water Pollution Control Act, enacted in 1985, more and more wetlands have been sheltered under the umbrella of central protection. Wetlands still face a barrage of threats from real estate and agricultural development. The subject of wetlands comes under the purview of Revenue department. This department is responsible for giving permission and allocating land for development purposes. While doing this, the ecological value of wetlands is not taken into consideration and wetlands are easily given over to development demands. Despite a plethora of laws and programs to protect them, wetlands are likely to encounter increasing development pressures. Apart from this, the pervasive definition fof Coastal Regulation Zone (henceforth, CRZ) converting even minor creeks and backwater extending several kilometres in the land, and stringent control of activities prescribed by the notification have complicated the task of evolving an implementable Coastal Zone Management Plan (henceforth CZMP). The problem is further compounded by the lack of base maps indicating high tide line that would satisfy the exact definition given in the notification. Besides, preparation of CRZ rules under CZMP, there is, at present, no defined policy or program to preserve wetland areas in MMR.

Some concrete steps needs to be taken to conserve the wetlands. Current estimates indicates that wetland area make up 1.12% of total land area in MMR. However, from satellite imageries, it is reasonable to assume that wetland areas have overall declined. If a study is conducted to identify the sites of these natural environment across the country, state or a city, can collectively provide an ecological feature layer for the city planners and environmentalists, to use in the decision making process.

Strategy
Eventhough, the recent study on Environmental Management strategy and Action plan for MMR (April 1994), mentions to some degree, a separate policy for wetland protection, fails in its recommendations to mention the causes of depletion of wetlands. The study also fails to assess more clearly the necessary magnitude of effort required and determine the Action Plan for necessary implementation measures. Wetlands comprise one of the earth's most productive natural ecosystems and have a skill for capturing and storing sunlight and efficiently recycling materials. They provide vital resting, breeding and feeding places for birds, help to maintain the water quality, controlling floods, etc. As a primary step it is necessary to explore the current issues in wetland preservations in MMR, critically examine Central, State and Local wetland regulations; and analyze and draw inferences from the successful wetland mitigation strategies undertaken in other parts of the world. One wetland biologist aptly cited the concept of Urban Renewal to illustrate the criteria that should be applied in protecting the degradation of existing wetlands. The current method of dealing with preservation of wetlands on a case-by-case basis is inadequate. The rather ungainful administrative framework makes the process inefficient and costly too. To minimize wetland degradation and to have integrated management and protection of wetland areas in MMR, the following actions could be initiated :

1. Identify the areas covered under the wetlands and estimating the loss of area under wetlands over a decade for the development projects.
2. Conduct an inventory of all wetland and mangrove areas in MMR including their condition, level of environmental stress and requirements for regeneration.
3. It is necessary to formulate a wetland conservation strategy. Norms and guidelines need to be prepared on the basis of which, conservation areas, such as wetlands can be considered. (such an effort has been already made in case of quarry areas in MMR).
4. Develop and implement a public education and awareness program on the value of wetland.
5. The responsibility for wetland/mangrove areas to be transformed from the Revenue Department to the Forest Department.
6. Use Environmental Conservation fund to provide additional assistance in financing schemes for conservation of wetlands.

Tools like Geographic Information Systems, Global Positioning Systems will be required along with the latest satellite imageries and aerial photos of the region, to identify the existing wetland coverage in the MMR. This type of joint collaboration program can be feasible through monitoring of international agencies like U.S.AID, MMRDA and with technical assistance from consultants will help in this regard.