Rehabilitation: the act of partially or, more rarely, fully replacing structural or functional characteristics of an ecosystem that have been diminished or lost, or the substitution of alternative qualities or characterisitcs than those originally present with the proviso that they have more social, economic or ecological value than existed in the disturbed or degraded state.
The majority of habitat "restoration" projects only achieve some degree of rehabilitation, i.e. the lesser goal of just increasing the social, economic or ecological value of degraded systems. This may involve alternative uses of degraded areas rather than a return to a former state.