This describes the reference states of natural habitats in Wales, many of which are confined to small fragments that are often located in areas unsuitable for human uses of the land. The modified states associated with each are also described, with this showing how different pressures on the landscape have impacted over varying time frames on these reference states and have led to the semi-natural habitats we see today. The different states of ecosystems and the transitions within and between states are also outlined, with this informing also on the potential for future restoration.