Nitrogen Deposition

Lichen Diversity (Lallement)

Description: 

This method was developed in France to provide a rapid assessment of air pollution particularly nitrogen over a large geographical area using 14 easily recognisable macro-lichen species associated with well defined phytosociological communities selected from the van Haluwyn and Lerond scale (1988). Land use in each unit was used as a basis for assessing nitrogen levels.

Lichen Acidophyte-Nitrophyte Diversity (Dutch method)

Description: 

Lichen diversity and cover is assessed on trunks of specified trees and weighted according to selected species that are classified as "nitrophytes" (species preferring nitrogen enriched tree bark) or "acidophytes" (species preferring naturally acidic clean tree bark). The method was developed in the Netherlands based on large-scale monitoring in conjunction with physicochemical measurements (van Herk 1999, 2002).

Invertebrates responses

Description: 

Insect pests: It is generally thought that the increased infestations of insect pests particularly sucking insects, observed following N addition from the atmosphere or as fertiliser, is a response to increased N content of the plants. While the presence of certain pests may indicate an effect of N deposition, their absence does not indicate the lack of an effect and the introduction of pests in order to observe change is not acceptable.

Frost Hardiness (Nitrogen)

Description: 

The ability of plants to minimise the risk of freezing damage is conferred by sychronising their phenology with the growing environment. The indigenous flora generally has a good safety margin between its frost hardened status and minimum temperatures, unless the growth environment changes. A negative link between enhanced N deposition and reduced frost hardiness was widely suspected to be a casual factor in the observed decline of red spruce in the nineteen eighties (Eagar & Adams 1992).

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