A scheme to relate nitrogen loads to characteristic plant species of FFH habitat types in Germany

There is growing evidence that high nitrogen loads can change species composition of different FFH habitat types. We developed a scheme especially for the plant species characteristic to the german variety of the habitat type 6230. For the scheme, three trophic levels were defined according to N loads found in literature. These results will be discussed in an expert workshop to revise and verify them. The trophic levels of the scheme are 10-12 N ha-1 y -1 , 12-14 N ha-1 y -1 and ≥ 15 N ha-1 y -1 .

It is widely acknowledged in the scientific community, that elevated nitrogen (N) deposition can change plant community structure in various ecosystems as for example in the FFH habitat type 6230 (EUNIS category E.1.7) (e.g. reviewed in Bobbink and Hettelingh 2011). Critical loads (CL) were defined to protect such ecosystems from degradation in Europe and were most recently revised by Bobbink and Hettelingh (2011). However, these empirical CL relate to rather broad habitat type (ht) categories in different regions of Europe. Therefore, we focused on plant species characteristic to the german variety of the FFH ht 6230, aiming to give an orientation how the conservation status of the ht might relate to different nitrogen loads.