Knowing how and why wetlands are changing is vital information for resource managers. NWI employs two basic approaches for evaluating wetland changes: 1) statistically based probabilistic sampling and 2) inventory of change. The former approach was developed for estimating status and trends of the nation's wetlands and involves analyzing changes in 4-square mile plots. This approach provides useful information for federal agency policy analysts but given its national focus is not as useful for guiding wetland conservation efforts at state and local levels.

The second approach – inventory of change – was developed by the region's NWI Program for obtaining more detailed and area-specific information on the nature of local changes and the underlying causes than generated by the Service's national status and trends study.

NWI+ is an expanded database where other descriptors are added to the standard NWI database to improve its utility for preparing more detailed characterizations of wetland resources and for predicting wetland functions at the landscape level.

Hydrogeomorphic-type descriptors describe landscape position (i.e., the relationship between a wetland and a watercourse or water body if present), landform (the shape or physical form of a wetland), and water flow path (the directional flow of water). Other descriptors address the diversity of water bodies, especially for ponds, since every wetland trend study has shown an increase in pond acreage while vegetated wetlands declined.

Potential wetland restoration sites include former wetlands that have been drained or filled but are still in a condition where restoration is possible and existing wetlands that have functions impaired by ditching, excavation, impoundment, or cultivation. The former sites are identified using soil maps and locating hydric soil areas that are not mapped as NWI wetlands and do not have any buildings or other structures built upon them. These restoration site inventories are now often part of watershed-based wetland inventories and functional assessments as the data used in these investigations make it easy to document potential restoration sites.

Through the watershed assessments, it is also possible to identify sites for possible restoration of streamside (riparian) vegetation. Depending on project funding and objectives, the region's NWI Program is attempting to include wetland restoration site inventories as part of its standard NWI updating procedures.

Looking beyond wetlands to the entire watershed is important to assess the health of wetlands and waters since activities in the surrounding landscape significantly affect water quality and habitat quality of wetlands. The condition of wetland and stream buffers is particularly important for wetland and aquatic wildlife. The widespread availability of land use/cover geospatial data make it possible to integrate NWI data with these data to evaluate and report on the condition of natural habitat surrounding wetlands and water bodies and for watersheds as a whole. To accomplish this, the region's NWI Program developed a set of "natural habitat integrity indices" that can be used for reporting on the condition of natural habitats for large geographic areas – a suite of useful metrics for an environmental report card.