Impact Type: Deposition of pollutant
Wood cow-wheat (Melampyrum sylvaticum) is an annual hemiparasitic herb of upland woodlands mostly in northern Britain and Northern Ireland. Occurrences are very localised. It is a species listed in the UK BAP. It may be sensitive to Nitrogen deposition, as other woodland ground flora, but this seems unlikely given its tendency to parasitism (carbon is acquired from the host and via photosynthesis direct), unless concentrations are very high (toxicity). However, Hattenschwiler & Korner (1997) showed that nitrogen has little effect and that atmospher ic CO2 enrichment is more important.
Melamphyrum species supplement their carbon supply from a variety of host plants via a 'fragile' haustoria, even falling twigs can damage plants. Therefore, trampling and increased 'traffic' through a woodland could be detrimental to the species. Vitality fitness can be assessed from seed production. Herbivory does not appear to present a threat (Lehtila & Syrjanen). The species can be colonised by various 'rusts' (Kaitera 1999) and increasing N deposition will probably favour such pathogens.
|Critical Load/ Level|
No comparable habitat with established critical load estimate available