WEED ECOLOGY
A Very Brief Introduction to Coastal Dunes.
Coastal dunes can vary significantly from one beach to the next.
However, the morphology and vegetation of coastal dune systems
can be classified into zones that run roughly parallel to the shore
line. The communities differ in terms of vegetation structure,
composition and disturbance history. These are important differences
when studying invasive species, because they have the potential
to moderate the impacts and degree of invasion within a community.
The three main zones of a coastal dune system are described below:
1. Strand
The first vegetative zone immediately behind the beach is
referred to as the ‘strand’ or ‘pioneer zone’.
This area is inhabited by primary stabilizing plants, predominantly
Spinifex sericeus (Hairy Spinifex). When dunes first begin
their development, the primary species are the first to inhabit
the
area. They promote the establishment of secondary species
by trapping additional sand and stabilizing existing sand.
This
results in further dune formation and build-up behind the
strand line, and the development of a fore dune.
2. Fore dune
Coastal fore dune communities are typically comprised of
shrubland (<1.5m tall) vegetation. Storm action and proximity
to the beach mean inhabiting species must tolerate a harsh
and
disturbed
environment that is often exacerbated by human recreation.
Common plant species include shrubs such as Acacia
longifolia var. sophorae (Coastal Wattle) and Leucopogon parviflorus (Coastal
Beard-heath), and ground-cover species such as Scaevola
calendulacea (Fan
Flower) and Carpobrotus glaucescens (Pigface).
Foredune with some bitou
3. Hind dune
Lying behind the fore dune, the hind dune environment is
buffered from much of the natural and human induced disturbances
experienced
by fore dune communities. The underlying soils are also
much more stable allowing for the presence of tall (>10m)
canopy species along with shrubs, grasses and herbs. Hind dune
communities
are often classified as woodland or forest and may include
canopy species such as Banksia integrifolia (Coastal
Banksia), Eucalyptus
pilularis (Blackbutt) and Cupaniopsis anarcardioides (Tuckeroo).
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