Flora survey for Hamersley Drive recreation - Environmental ...

FRNP Improvement Project: Culham Inlet to Hamersley Inlet GF Craig– July 2010
Threatened Ecological Communities
No listed Threatened or Priority Ecological Communities were found during the field survey, although a
community of ecological significance is located on the wave-cut bench that extends south of East Mt
Barren.
Significant Ecological Community
The perched micro-wetlands on the wave-cut bench are considered to be a rare community on the south
coast (A. Chapman 2009; S.Comer, pers.comm.). These sedge-dominated communities occur within the
Banksia speciosa vegetation unit and have permanently wet soil fed by freshwater from further upslope -
they were too subtle to map individually. A number of small, freshwater pools were present. According
to Chapman (2009) they are significant because “they maintain small patches of mesic environment in
an otherwise very fire prone and possibly drying environment”.
Currently, Hamersley Drive cuts through these micro-wetlands, but the porosity of the road base does
not appear to be impeding water flow. It is imperative that any upgrade does not prevent natural water
flow downslope of the road, nor cause unnatural ponding of water on the upside.
Vegetation Condition Assessment
The vegetation was generally in excellent health, although small patches of weeds were observed at
some campsites and recreation nodes. These are described in more detail below.
Fire
In 1989, much of the survey area was burnt during a wildfire started by lightning strikes. Now, twenty
years later, most of the plant communities have re-established with the majority of plants being sexually
mature (producing fruits and seeds).
An escaped prescribed burn in October 2006 burnt most of an area between West Beach Road and the
western slopes of East Mt Barren area for a second time. Resuckering species are up to 1 m tall, with
many having flowers and/or fruits, while obligate seeder species are still establishing. Sandier soils have
some relatively bare patches, although overall the original pre-burn suite of plants appears to be
establishing successfully. Notes were taken during the survey of the method of regeneration of plants, ie
resuckering from rootstock or obligate seeders (see Appendix 5).
Climate change
Following the hottest day (48 o C) on record for
Hopetoun in January 2010, along with the strong
northerly winds with only 5% relative humidity,
many species in the FRNP showed signs of
severe scorching. Species along Hamersley
Inlet Road that were particularly affected with
>70% leaf death on numerous individual plants
were Acacia phlebopetala, A. moirii spp.
dasycarpa, Allocasuarina humilis, Andersonia
parviflora, Banksia nutans, B. violacea, Daviesia
emarginata, D. incrassata ssp. reversifolia, D.
striata, Dryandra quercifolia, Hakea trifurcata,
Isopogon sp. Fitzgerald River, Lambertia inermis,
Leptospermum sp. Bandalup and Petrophile
squamata ssp. northern.
23