N deposition :: Capercaillie

Latin name: 
Tetrao urogallus

Impact Type: Deposition of pollutant

Key Concerns:

Increases in nitrogen deposition to Scots pine forest may be beneficial to adult capercaillie, as there are potential changes to nutrient value of the pine needles which the adult birds feed on in winter (Spidsx & Korsmo 1993).

Additional Comments:

The changes to the ground flora may nevertheless have a knock on effect on the feeding success and survival rate of the chicks, thus reducing breeding success. There is no published research on which to base a definitive answer to this question. Effects of N deposition are expected to be small by comparison with those due to climate change. Likewise, management intervention to control predators will be important. Given that Blaeberry and Scots pine shoots form an integral part of the diet, loss of Blaeberry shoots due to N/winter damage will have a detrimental effect on breeding success. An increase in the amino acid content of Pine needles would be expected to have a beneficial effect so long as the enhanced foliar N levels do not cause a mismatch between budburst, late frosts and the feeding demands of the breeding buds.

��G'�p(�o and NO3- (Risager 1998). Carfrae et al 2002 showed changes in the ratio of oxidised to reduced Nitrogen could potentially alter the balance between different Sphagnum species growing in bogs. Response to nitrogen is dependent on the availability of Potassium, and is also influenced by the height of the water table (Williams et al 1999). Nitrogen tends to accumulate in the Sphagnum as amino acids so that initially almost none of the additional nitrogen is available to other plant species. Aerts et al (1992) recorded a 4 fold increase in the growth of S. balticum in response to additions of 20 and 40 kg N in Sweden (background 0.4 kg N ha-1 yr-1). Growth stimulation is phosphorous dependent. 

 

Critical Load/level: 
Critical Load/ Level

No comparable habitat with established critical load estimate available

References: 
Spidsx, T.K.; Korsmo, H. 1993 Effect of acid rain on pine needles as food for capercaillie in winter Oecologia 94 565-570
Species group: 

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