Fens, wetlands and peatlands are under threat due to drainage for agricultural use. Other activities that are having a significant effect on these areas are peat extraction for the horticultural industry, for fuel and industrial use and for commercial afforestation with fast growing exotic species. Pollution with agrochemicals, industrial sewage, farm waste, agricultural lime, effluent from processing agricultural produce and acid deposition is a cause for concern for these areas. The enrichment (eutrophication) caused by pollution means a change in acidity and nutrient status that will affect the wildlife and alter the quality and rate of accumulation of peat. Fire is also a threat to the ecology of these areas.
Wetlands are areas inundated or saturated by water at a frequency and duration sufficient to support permanent, semi-permanent or episodic aquatic communities. This means species adapted for life in saturated soil conditions. Wetlands are often lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water arising from surface flows.
Fens are characterized by a high water table with slow internal drainage by seepage down low gradients. Their surface waters may be acidic or alkaline. Fens are not as low in nutrients as bogs and as a result are more productive. Although fens are dominated by sedges they may also contain shrubs and trees.