In Pembrokeshire, good breeding sites consist of heathlands that contain ground water-fed permanent flushes and shallow streams within heathlands. The streams have a gravely or clayey bed with patches of organic detritus. The watercourses are well vegetated, but have areas of open water. Emergent water plants that mark suitable habitat include Bogbean Menyanthes trifoliata, Marsh St John’s Wort Hypericum elodes, Bog Pondweed Potamogeton polygonifolius and Fool’s Watercress Apium nodiflorum.

The Southern Damselfly was once more widespread in Pembrokeshire. Two of the three main populations have gone extinct, leaving small, scattered populations within and around the Preseli SAC which is also common ground. These are now vulnerable due to a large reduction in grazing, especially of larger stock. This lack of grazing has led to flushes becoming swamped and choked by adjacent vegetation, thereby making the habitat unsuitable for Southern Damselflies. Past monitoring has shown that the population of Southern Damselfly in Pembrokeshire have declined in recent decades and in many cases clinging on to the last fragments of habitat that are still suitable, but no longer ideal.

Recent changes in land management have put particular pressure on the existing populations in Pembrokeshire. The Southern Damselfly needs well-grazed and open vegetation beside small streams. It is also beneficial for the streams to have trampled margins and tussocks created by heavy grazing animals, like cattle or horses.

There are many constraints to achieving the correct grazing regimes for Southern Damselflies on common land. These constraints are due to economic, legal and cultural reasons. There are also many separate parties with an interest in common land, resulting in there being a number of individual issues to overcome before the practical problems can be considered and assessed.