The habitats in this section are generally considered to be ‘semi-natural’ in that they are historically recognised as having been a part of the UK landscape for hundreds, if not thousands, of years. They also tend to be dominated by species considered native to the UK. However, they invariably have a history of cultural management and, with the possible exception of some cliff ledges, been impacted indirectly by the actions of humans, i.e. through acid rain and atmospheric nitrogen depositions. The biodiversity associated with these habitats can be strongly linked to how they are managed, and removing that management will often result in significant declines in biodiversity. As such, management changes should be considered carefully and strategically.
Semi-natural ecosystem components
Forests and Woodland
This section provides brief descriptions of the commoner woodland ecosystems in Wales, outlining both the reference state/s and the commoner modified states likely to be encountered. The scrub habitats are described first, then the pioneer woodland types, followed by mature broad-leaved woods and finally yew woodland, dominated by the only native needle-leaved tree in Wales.
Bracken and scrub
The sections below cover the most common forms of bracken and scrub in the Welsh landscape. There are many other scrub forming species in Wales, such as dogwood (Cornus sanguineus) and wayfaring tree (Viburnum lantana), but these are the species that you are most likely to come across. On sand dunes, sea buckthorn (Hippophae rhamnoides)…
Semi-natural grasslands
Most of the land area of Wales is covered by grassland, much of this, if not all, has been modified through agricultural processes, atmospheric depositions or both. We have used an initial dichotomy of dry grassland and marshy grassland, with more detailed descriptions of the main grassland types provided under the relevant section. Note that…
Heaths and mires
This section covers the heath and bog habitats in Wales, all of which are considered to be under threat and listed in Annex I of the EC Habitats Directive. There tends to be a lot of overlap between the dominant species in these habitats, making the habitats potentially difficult to differentiate, particularly in transitional states.…
Fens and swamps
Fen and swamp habitats often occur together, forming complex mosaics in areas of waterlogged ground, the differences can be difficult to clearly define. Generally, swamps tend to be dominated by tall grasses, e.g. common reed (Phragmites australis), or scrub, while lowland fens can encompass a wide range of wetland types on wet acid, neutral or…
Coastal Dunes
Although sand dune systems are well represented around the Welsh coastline, they are much less well represented in Europe as a whole. The most important sites are located mostly along the Atlantic coast, i.e. in the UK, France, and Spain, and in The Netherlands. Virtually all phases of dune development are listed in Annex I…
Cliffs, boulder fields and screes
Cliffs and screes are found mostly around the coast and in the mountains in Wales. Cliff ledges and crevices provide a refuge for rare wildlife, notably for Peregrine falcons and iconic species of plant, such as the Snowdon lily (Gagea serotina) and yellow whitlow grass (Draba aizoides). Scree and boulder habitats can also be important…
Estuaries
Estuaries are highly productive ecosystems that form where rivers enter the sea: in Wales, this is often signified by the Welsh place name having the pre-fix ‘Aber’ and followed by the name of the river, e.g. Aberystwyth, Aberdyfi etc. The larger, fully developed, saltmarsh systems, e.g. the Severn Estuary, the Dee Estuary and the Burry…
Standing waters and watercourses
This section covers standing waters, streams and rivers. These habitats, and the species associated with them, are particularly vulnerable to changes relating to pollution incidents and climate change. Changes in temperature and the periodicity of inundation, influenced by the changing seasonality and levels of precipitation, can have a dramatic impact on the biodiversity of the…
Intertidal
All of the broad habitats outlined briefly here are either inundated by water or exposed to the air at least partially for a few days each year, though some will experience both daily, making them potentially visible on satellite images and by drones. They differ from most of the other habitats covered here by being…