Coastal and rocky habitats

Ozone :: Coastal and Rocky Habitats

Effects and Implications

  • Visible leaf injury and/or premature leaf die-back, which could subsequently result in reduced growth during a growing season;
  • Reduced growth of sensitive species;
  • Potential alterations in numbers and timing of flowering and seed production;
  • Alterations of response to other environmental stresses such as drought stress;
  • Potential enhanced susceptibility to pests and diseases.

Soil gas fluxes


The gases NO and N2O are produced in soils by nitrifying and denitrifying bacteria, and the magnitude of the emissions is controlled by the availability of N as ammonium (NH4) or nitrate (NO3) and also by certain climatic and soil properties which promote nitrification or denitrification, e.g. temperature, rainfall, organic matter content (Skiba & Smith 2000).

N:P ratio in leaf tissues


Where plant growth may be limited by P availability or when enhanced N deposition may lead to reduced availability and/or uptake, measurements of the N:P ratios in selected species may provide a better indication of N saturation. Optimum N:P ratios for plant growth range from 10-14 (van den Driesshe, 1974; Ingestad, 1979). Low ratios (<10) indicate N limited growth and high ratios (>14) indicate P limitation (Koerselma & Meuleman, 1996).

Previous experience:

Invertebrates responses


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)


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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