Information on the ecological values of wetlands is important to evaluate their contribution to social and economic well-being and thus, to improve their management. Awareness of the wetland role in creating and maintaining biodiversity, and especially their support role to migratory birds, has led to worldwide initiatives of conservation.
Wetlands host complete food chains with producers, consumers and decomposers that purify water as it flows to the sea. As in all ecosystems, the succession of micro-organisms that occurs in detritus (involving bacteria and fungi as well as detritus-feeding invertebrates) reduces organic material to elemental nutrients. Wetlands are major "sinks" of nutrients and pollutants and are particularly important in the conversion of nitrates to harmless nitrogen gas. This is due to denitrifying bacteria that are especially active in waterlogged anaerobic soils.
The nutrient cycling pattern of wetlands determines the biodiversity they sustain. The hydrological change brought by reclamation is bound to bring a shift in the composition and concentration of plant and animal species that can only be felt in the longer term.
Biological information on wetlands includes plant and animal resources, major habitats and reproduction sites, and presence of special species. In this respect, a quantification (or qualification) of wetland primary and secondary productivity, biodiversity and abundance of species (e.g. waterfowl), habitats for shorebirds nesting and roosting, important flyways, hatching and nursery areas for fisheries, threatened and endangered animal and plant species, exchange zones, etc. are all important aspects.
The energy and nutrient flow that governs wetland productivity and the various environmental services should be understood. Tides, sedimentary dynamics, watershed inputs, hydric balance (in surface, underground and coastal waters), water quality, salinity and permanence, local climatic conditions, soils, etc. are all important to investigate.