Section 404 of the Clean Water Act requires mitigation to offset wetland losses. Thus far, all mitigation required under this Act has been for the creation and/or restoration and enhancement of existing wetlands. It would not be that much of a policy stretch to require that at least some mitigation for loss of coastal wetlands include an inland buffer that would contain potentially inundatable lands. Buffers are often required in existing wetland mitigation projects anyway in terms of protection from development and polluted runoff.
But because there is no statutory requirement for protection of dry lands that might one day become wetlands, a major policy change would be needed at the agency level, and perhaps even an act of Congress to effectuate such a change. On the state level, however, especially in a state like Florida with a robust wetland program, it would be relatively easy to require mitigation that preserves inundatable lands, although state politics could also encounter legislative hurdles to overcome to effect such a change.
There is nothing to stop non-profits from purchasing inundatable lands, or purchasing the development rights to those lands. Given the rapid and massive loss of existing wetlands to development right now, it is probably unreasonable to expect many land trusts to devote significant resources to future wetlands. If, however, these organizations were sensitized to the need for this kind of preservation, they might easily be able to work additional upland buffers into coastal wetlands preservation projects that they would be working on anyway.