foredune complex, with some blowout and parabolic dune development at the
northern (relatively exposed) end of the barrier. At this time the flora of the barrier
would have comprised both dune-specific and cosmopolitan scrub and forest
margin plants. Some species, including the endemic Euphorbia glauca (shore
spurge) and the indigenous sand tussock, (Poa billardierei (Spreng.) Soreng et al.
2009; formerly Austrofestuca littoralis), had probably been eliminated by introduced mammal browse and granivory before marram invasion. Pı ¯ngao (Ficinia
spiralis (A. Rich.) Muasya and de Lange 2010; formerly Desmoschoenus spiralis)
would have grown across much of the barrier, and moribund colonies persist where
marram grass has not invaded. Only one pı ¯ngao plant was observed within the
marram foredune ridge sequence in 1999. Ironically, the diversity of the marramdominated ridges was very high—a consequence of the stability and senescence of
marram on the inner ridges as the barrier prograded.
The geomorphology of the barrier was also transformed. Transgressive dunes,
blowouts and, parabolic characterized the surface of the pre-marram barrier;
however, these dunes are now stable and vegetated, since they are located in the
lee of the sequence of marram-forced foredunes. In 1999 the seaward half of the
barrier comprised a series of linear foredunes (Figs. 5.10, 5.11). Remnant blowouts and saucer-shaped parabolic dunes, now stable, occupy the landward half of
the barrier. During the period from 1958 to 1998 the southern barrier prograded
60–200 seaward and 400 m to the north. This northward growth of the barrier was
forced by marram colonization of the pre-marram barrier margins. Pı ¯ngao may
have been established there from time to time, but both aeolian and marine
sedimentation would have prevented prolonged colonization and foredune
establishment.
The Doughboy case is typical of the impact of marram grass on the dune
systems of southern New Zealand. The DoC intervened in the Doughboy Bay case
Fig. 5.10 An aerial oblique view of the southern barrier. The ‘‘scarp’’ separates the prograded
foredune barrier associated with marram, which formed after the first aerial photograph was
obtained in 1958 from the pre-marram dune system. The latter contains remnant blowouts and
parabolic dunes
5 Restoration of Foredunes and Transgressive Dunefields
79
northern (relatively exposed) end of the barrier. At this time the flora of the barrier
would have comprised both dune-specific and cosmopolitan scrub and forest
margin plants. Some species, including the endemic Euphorbia glauca (shore
spurge) and the indigenous sand tussock, (Poa billardierei (Spreng.) Soreng et al.
2009; formerly Austrofestuca littoralis), had probably been eliminated by introduced mammal browse and granivory before marram invasion. Pı ¯ngao (Ficinia
spiralis (A. Rich.) Muasya and de Lange 2010; formerly Desmoschoenus spiralis)
would have grown across much of the barrier, and moribund colonies persist where
marram grass has not invaded. Only one pı ¯ngao plant was observed within the
marram foredune ridge sequence in 1999. Ironically, the diversity of the marramdominated ridges was very high—a consequence of the stability and senescence of
marram on the inner ridges as the barrier prograded.
The geomorphology of the barrier was also transformed. Transgressive dunes,
blowouts and, parabolic characterized the surface of the pre-marram barrier;
however, these dunes are now stable and vegetated, since they are located in the
lee of the sequence of marram-forced foredunes. In 1999 the seaward half of the
barrier comprised a series of linear foredunes (Figs. 5.10, 5.11). Remnant blowouts and saucer-shaped parabolic dunes, now stable, occupy the landward half of
the barrier. During the period from 1958 to 1998 the southern barrier prograded
60–200 seaward and 400 m to the north. This northward growth of the barrier was
forced by marram colonization of the pre-marram barrier margins. Pı ¯ngao may
have been established there from time to time, but both aeolian and marine
sedimentation would have prevented prolonged colonization and foredune
establishment.
The Doughboy case is typical of the impact of marram grass on the dune
systems of southern New Zealand. The DoC intervened in the Doughboy Bay case
Fig. 5.10 An aerial oblique view of the southern barrier. The ‘‘scarp’’ separates the prograded
foredune barrier associated with marram, which formed after the first aerial photograph was
obtained in 1958 from the pre-marram dune system. The latter contains remnant blowouts and
parabolic dunes
5 Restoration of Foredunes and Transgressive Dunefields
79