Vascular Plants

N deposition :: Juniper

Impact Type: Deposition of pollutant

Key Concerns:

Juniper, Juniperus communis, is a member of the cupressaceae and is found on limestone heathland and moorland where it can be widespread but local (Biodiversity Steering Group 1995). It is not known to be sensitive to air pollution. Such sites are normally co N/P limited so that growth responses to N would be limited. Generally growth is slow.

Additional Comments:

N deposition :: Irish Lady's tresses

Impact Type: Deposition of pollutant

Key Concerns:

Irish Lady's tresses (Spiranthes romanzoffiana) is a rare orchid of boggy pastures and meadows which occurs particularly in Northern Ireland, the extreme west of Scotland and at one site in England in south Devon (Biodiversity Steering Group 1995). This UK BAP species has declined in intensive agricultural areas, probably due to eutrophication and habitat loss. Atmospheric N deposition is expected to be a contributing factor since it will increase competition from grasses and tall forbs.

N deposition :: Filmy ferns

Impact Type: Deposition of pollutant

Key Concerns:

Filmy ferns (Hymenophyllum spp) are small ground or epiphytic ferns often associated with bryophyte communities. They are likely to be sensitive to nitrogen deposition. However, there is no published research on the effect of air pollution on this group, so it is uncertain how filmy ferns compare in sensitivity to bryophytes. As a first approximation, a similar sensitivity might be assumed to the more sensitive bryophyte species.

Additional Comments:

N deposition :: Blaeberry

Impact Type: Deposition of pollutant

Key Concerns:

Blaeberry, Vaccinium myrtillus, is an important component of the understorey vegetation in native pine woodland and plays an important role in the life cycle of some birds (i.e. Capercaillie). A number of studies has shown that raised levels of N deposition lead to increased growth of grasses at the expense of ericaceous shrubs such as Blaeberry (Pitcairn et al. 1998, De Vries et al. 1995).

Additional Comments:

NH3 :: Twinflower

Impact Type: Direct exposure to pollutant

Key Concerns:

Twinflower (Linnaea borealis), which is adapted to very nutrient poor sites (Hill et al. 1999), is listed in the UK BAP. It is restricted to pine woodland or shaded rocky places in eastern and northern Scotland, where it has under gone substantial decline in the 20th century. The reason for this is unclear.

Additional Comments:

NH3 :: Scots pine

Impact Type: Direct exposure to pollutant

Key Concerns:

The health of Scots pine in central and western Europe, and in forests such as Thetford, may be affected by increased atmospheric ammonia emissions from intensive livestock farming. Symptoms include needle yellowing, needle loss and large concentrations of N in the foliage. While this problem is largely associated with the Netherlands, there is evidence of damage to Scots pine in the vicinity of intensive animal farms in Scotland (Pitcairn et al. 1998).

NH3 :: Ferns (general)

Impact Type: Direct exposure to pollutant

Key Concerns:

Available evidence suggests that ferns are sensitive to elevated ammonia concentrations (Schumann and Mills 1996, Pitcairn et al. 1998). Measurements of Pitcairn et al. (1998) showed changes in Dryopteris dilatata abundance near to intenstive livestock farms.

Additional Comments:

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