Nitrogen Deposition

Nitrogen Deposition :: Dunes, Shingle & Machair

Pollutants: 

Effects and implications

  • These systems are adapted to low levels of mineral N availability: increasing the availability of N will threaten the competitive balance between species leading to changes in composition and loss of habitat species constants.
  • Speeds up succession through the chronosequence, movement between the dune stages.
  • Lichens and mosses are particularly sensitive both from direct effects associated with N accumulation and from shading as a consequence of increase growth of overstorey vegetation in response to N deposition

Nitrogen deposition :: Coniferous woodland

Pollutants: 

Effects and implications

Trees

  • Increased yields greatest where soil organic layer C:N ratio high (Guerrieri et al 2011).
  • Destabilisation; faster growth, reduced investment in roots leading to increased risk of drought stress (Anders et al 2002) and increased risk of uprooting.
  • Decreased fine root biomass and numbers of root tips, with associated increased above ground biomass, indicative of micro nutrient deficiencies induced by excessive growth.

Nitrogen deposition :: Broadleaved, Mixed and Yew Woodland

Pollutants: 

Effects and implications:

Trees

  • Increased growth, greatest where soil organic layer C:N ratio is high.
  • Destabilisation; faster growth, reduced investments in roots leading to increased risk of drought stress (Anders et al 2002) and increased risk of uprooting. Damage to mature beech in the 1999 storm in Switzerland positively correlated with leaf N (Meyer et al. 2008)

Nitrogen deposition :: Acid grassland

Habitats: 
Pollutants: 

Effects and implications

  • Nitrogen deposition provides a fertilization effect on acid grasslands which are generally N limited.
  • N deposition favours graminoids (grasses) at the expense of forbs and lower plants, especially where sites are surrounded by farmland.
  • Nitrophilous grasses tend to shade out slower growing species.
  • Nitrophilous grasses increase the amount of litter which falls on and shades out under-storey bryophytes (Berendse et al 1987).
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