4.4.4 Species Composition Dynamics
The groups of relevées that resulted from the TWINSPAN analysis appear to be
meaningful in several ways.
The gradual increase in species richness of the dune system from year 1 to year
24 was reflected in the number of TWINSPAN groups represented, which
increased from two to five, indicating an increasing habitat variation within the
dune system.
Second, the grouping clarifies, together with the changes in morphology, the
developmental trends in the dune system in the seaside park up to 2002. The
spatial position of the active dune formation, as indicated by the relatively high
speed of dune growth, gradually moved seaward from 1979 to 2002, leaving
behind an increasing area of stabilized dunes. This dynamic was reflected in the
distribution of the TWINSPAN groups (Table 4.4). The initial, man-made dune
during the first years was covered by group A vegetation, which was mostly based
on the Ammophila that had been planted. After a few years this vegetation changed
into group B1 or C1 vegetation, which after 14 years stabilized into C2 vegetation
or dune grassland (C3). In the oldest of the new, naturally formed foredunes
seaward to the man-made dune, the successional development followed the
sequence (A ?) B1 ? B2 ? C1, which reflects the increasing stability and
species richness. The younger, more seaward dune in 2002 had only reached group
B2 in this sequence, while the development of the youngest dune by 2002 had
occurred within the variation of group B1.
Third, the sequence of the TWINSPAN groups largely matches the succession/
zonations previously described from the younger parts of coastal dunes elsewhere
at the Baltic and in northwest Europe (e.g., Warming 1909; Ranwell 1972; Olsson
1974; Hundt 1985; Vestergaard 1991; Packham and Willis 1997; Frederiksen et al.
2006). This indicates that the dune vegetation in the seaside park developed
according to the same successional and ecological processes as in natural coastal
dunes. This result agrees with the experience of De Lillis et al. (2004) with
man-made dunes on the Mediterranean coast.
4.5 Conclusions
For 24 years, the initially man-made dune in the Køge Bay Seaside Park stabilized
quite quickly, while the beach expanded seaward because of the natural accretion
of marine sand. On the beach, three rows of coast-parallel foredunes developed
successively. The gradual change in plant diversity of the dune system, expressed
by a net increase in the species richness of the permanent plots from only one
planted species in 1978 to 26 species in 2002, could be related to the combined
effect of the following dune succession processes:
62
P. Vestergaard
The groups of relevées that resulted from the TWINSPAN analysis appear to be
meaningful in several ways.
The gradual increase in species richness of the dune system from year 1 to year
24 was reflected in the number of TWINSPAN groups represented, which
increased from two to five, indicating an increasing habitat variation within the
dune system.
Second, the grouping clarifies, together with the changes in morphology, the
developmental trends in the dune system in the seaside park up to 2002. The
spatial position of the active dune formation, as indicated by the relatively high
speed of dune growth, gradually moved seaward from 1979 to 2002, leaving
behind an increasing area of stabilized dunes. This dynamic was reflected in the
distribution of the TWINSPAN groups (Table 4.4). The initial, man-made dune
during the first years was covered by group A vegetation, which was mostly based
on the Ammophila that had been planted. After a few years this vegetation changed
into group B1 or C1 vegetation, which after 14 years stabilized into C2 vegetation
or dune grassland (C3). In the oldest of the new, naturally formed foredunes
seaward to the man-made dune, the successional development followed the
sequence (A ?) B1 ? B2 ? C1, which reflects the increasing stability and
species richness. The younger, more seaward dune in 2002 had only reached group
B2 in this sequence, while the development of the youngest dune by 2002 had
occurred within the variation of group B1.
Third, the sequence of the TWINSPAN groups largely matches the succession/
zonations previously described from the younger parts of coastal dunes elsewhere
at the Baltic and in northwest Europe (e.g., Warming 1909; Ranwell 1972; Olsson
1974; Hundt 1985; Vestergaard 1991; Packham and Willis 1997; Frederiksen et al.
2006). This indicates that the dune vegetation in the seaside park developed
according to the same successional and ecological processes as in natural coastal
dunes. This result agrees with the experience of De Lillis et al. (2004) with
man-made dunes on the Mediterranean coast.
4.5 Conclusions
For 24 years, the initially man-made dune in the Køge Bay Seaside Park stabilized
quite quickly, while the beach expanded seaward because of the natural accretion
of marine sand. On the beach, three rows of coast-parallel foredunes developed
successively. The gradual change in plant diversity of the dune system, expressed
by a net increase in the species richness of the permanent plots from only one
planted species in 1978 to 26 species in 2002, could be related to the combined
effect of the following dune succession processes:
62
P. Vestergaard