Dryandra Woodland - Department of Environment and Conservation ...

south coast national parks of Fitzgerald River and Walpole-Nornalup contain 1748 species and 698
species respectively (CALM 1992a, CALM 199 1 a).
The greatest floristic diversity can be found in the Lateritic Plateau Woodlands, Dryandra/Petrophile
Shrublands, Low Kwongan, Marri Woodlands and Lithic Complexes. These communities make up
only a small proportion of the total area of Dryandra. At a community level, Wandoo and
Powderbark Wandoo woodlands occupy nearly 50% of the area of Dryandra, yet have only
approximately 25% of the recorded native flora species. The major families represented are
Myrtaceae (76 species), Proteaceae (75), Papilionaceae (73), Asteraceae (72), Orchidaceae (65),
Mimosaceae (37), Poaceae (32), Anthericaceae (29) and Cyperaceae (26).
Threatened and Priority Flora
All native flora are protected under the Wildlife Conservation Act (1950), but declared rare flora
(DRF) are given special protection. The DRF list is reviewed annually and published in the
Government Gazette. Currently there is two DRF species within the Dryandra Woodland (see
Appendix 1). In addition, CALM maintains a priority species list for flora that are poorly known and
in need of further survey, or are adequately surveyed but in need of monitoring. Twenty priority
species have been recorded in Dryandra, most of which require further survey to adequately assess
their conservation status (see Appendix 1).
Fungi, Mosses and Liverworts
In addition to the diverse array of vascular plants, there are many species of fungi, mosses, liverworts
and lichens. While only limited surveys of these groups have been conducted, to date more than 100
species of 'larger fungi' have been recorded in Dryandra. Many of the 'larger fungi' are hypogean
(underground) species, an integral part of the Woylie's (Bettongia penicillata) diet (Christensen
1980). Most species of hypogean fungi are also mycorrhizal, growing within or on the outside of
plant roots. This symbiotic relationship assists nutrient uptake by plants.
Keystone Species
A keystone species is one which, if removed, would precipitate significant losses of other species
(Gilbert 1980). Structurally dominant species that fruit, flower or seed outside the normal peaks in
community production, or that produce high levels of a reliable resource, may be important in
maintaining community cohesion. Possible keystone species include the hypogean fungi of the
Woodland.
Disturbance Cycles
Plant communities and populations may be severely disrupted by disturbances such as windstorms,
flood, fire and drought. Depending on factors such as season, species, and frequency of disturbance,
plants may temporarily disappear or be reduced in numbers. Often these disturbance events act as
'reset mechanisms', returning a plant community to an earlier seral stage. Rock Sheoak
(Allocasuarina huegeliana) and Brown Mallet forests are both vegetation associations that can
regenerate as single-aged stands following a disturbance event such as fire (see also Section 19. Fire).
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