Nitrogen limitation in the coastal heath at Anholt, Denmark

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Ib Johnsen, Steen Christensen, Torben Riis-Nielsen

The purpose of the study was to investigate, whether
the coastal grey dune vegetation at Anholt, Denmark, is
limited by nitrogen or phosphorus. The island Anholt
(22,37 km2) is situated in the centre of Kattegat A two factor
fertilization experiment with nitrogen as NH4NO3 (Naddition)
and phosphorus as KH2PO4 (P-addition) was carried
out in the coastal grey dune vegetation of Anholt. The Naddition
corresponded to 40 kg N ha−1 year−1 and the Paddition
to 7 kg P ha−1 year−1 The experiment included N-,
P-, N + P-addition and control. Lichens (genera: mainly
Cladonia, Stereocaulon, Cetraria, Hypogymnia) and bryophytes
(genera: Polytrichum, Racomitrium) cover most of
the surface. Only two plant species, Corynephorus canescens
and Empetrum nigrum, constitute nearly all vascular plant
cover and biomass of this calcium poor coastal heath community.
Corynephorus and Empetrum increased their cover significantly
following N and N + P addition. No effect was
observed by P addition alone. N limitation of this coastal
heath vegetation remote from agricultural and industrial activities
was evident. The effect on the plant species of the
single application was short-lived. After two-three years of
enhanced cover, the Corynephorus and Empetrum cover had
returned to their level before the experiment. The lichen
vegetation, however, changed more permanently, and after
12 years the subplots with N + P addition was dominated by
rich growth of Cladina and Cetraria species. The results are
discussed in relation to anthropogenic nitrogen deposition and
conservation of this high priority ecosystem
Original languageEnglish
JournalJournal of Coastal Conservation
Issue number4
Pages (from-to)369-382
Number of pages14
Publication statusPublished - 2014

ID: 113375047