Impact Type: Deposition of pollutant
Key Concerns:
Twinflower, Linnaea borealis, which is adapted to very nutrient poor sites (Hill et al. 1999), is a priority species in the Scottish Biodiversity Ac tion Plan (Usher 2000) and is also listed in the UK BAP. It is found in pine woodland in eastern and northern Scotland. It has been declining since the turn of the 20th century. Increases in nitrogen deposition, which have been observed to affect woodland ground flora (Pitcairn et al. 1998), may be contributing to this decline by encouraging growth of fast growing competitors.
Additional Comments:
Westlund and Nohrstedt (2000) have shown that in Sweden the use of urea in the treatment of cut tree stumps substantially increases local ammonium concentrations and causes severe damage to understorey vegetation killing L. borealis by direct toxicity.
| Habitat/ Ecosystem Type | Eunis Code | Critical Load/ Level | Status | Reliability | Indication of exceedance | Reference |
|---|---|---|---|---|---|---|
| Broadleaved deciduous woodland | G1 |
10-20 kg N ha-1 year-1 |
UNECE 2010 - Noordwijkerhout workshop | reliable |
Changes in soil processes, nutrient imbalance, altered composition mycorrhiza and ground vegetation. |
472 |