Pollutant-Habitat | 17.12.2024

Nitrogen deposition :: Neutral Grassland

Effects and implications

  • Increases in proportion of productive grasses at expense of fine leaved grasses.
  • Reduces species richness, especially among forbs
  • Possible reductions in productivity
  • Changes in species composition
  • Loss of rare or endangered species.
  • Loss of annuals and forbs will have implications for sustainability, due to the short lived nature of the seed bank (Bossuyt et al 2005) and the isolation of many of these small areas of grassland.
  • Loss of floral diversity, especially forbs/ herbs can reduce nutritional quality

Pollutant-Habitat | 17.12.2024

Nitrogen deposition :: Montane Habitats

Effects and implications

  • Eutrophication: 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.
  • Lichens and mosses are particularly sensitive to nitrogen both from direct effects associated with N accumulation and from shading as a consequence of N stimulated growth of over-storey vegetation.
  • Terricolous lichens (lichens growing on the ground): growth of some species is very sensitive to N con

Pollutant-Habitat | 16.12.2024

Nitrogen Deposition :: Inland Rock & Scree

Effects and implications

  • On P limited sites direct effects of N accumulation can affect lichens and mosses leading to species loss and a reduction in species richness.

Overview: evidence, processes and main impacts

Limestone pavements

Limestone pavements have not been studied specifically with respect to N deposition but aspects of responses of communities on calcareous grasslands and neutral/acid gra

Pollutant-Habitat | 16.12.2024

Nitrogen deposition :: Hedgerows

Effects and implications

  • Loss of sensitive lichen species

Overview: evidence, processes and main impacts

Hedgerows can support N sensitive epiphytes. Species diversity is often restricted by the absence of a source of appropriate seed, caused by the use of highway management herbicides, and cutting restricting seed and berry production.

Hedgerows containing evergreens will be sensitive to ammonia, especially during the winter when low temperatures compromise assimilation leading to toxicity and exacerbation of winter desiccation.

Pollutant-Habitat | 16.12.2024

Nitrogen Deposition :: Dunes, Shingle & Machair

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
  • Species sensitivi

Pollutant-Habitat | 16.12.2024

Nitrogen deposition :: Coniferous woodland

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.
  • Mechanical stability - broken stems associated with less non-structural carbohydrate