ppendix 10: Weed, Dieback and Native Flora assessment of the Millbrook Nature Reserve wetland, King River wetlands, and Seven Mile and Five Mile Creeks, by the Denmark Weed ction Group and the Denmark hytopthora cinnamomi Working Group.
Wetland Survey March 3 + 4, 2008
SUMMARY: x Millbrook Nature Reserve is important for the conservation of several Declared Rare Flora species x Dieback disease, caused by the soil pathogen Phytophthora cinnamomi, is present in parts of the reserve, causing the deaths of many species, including some of the DRF x Changes to the hydrology of the catchment has caused the deaths of Paperbark trees in the lower section of the reserve. x Weed infestations within the reserve occur only in two isolated sites, in the floodplain of the western arm of the creek system
Millbrook Nature Reserve
Method: Millbrook Nature Reserve was visited on March 3 & 4, 2008. We inspected part of the reserve on the southern boundary (accessable thru the Bluegum plantation), as well as driving along the fire access trail from the NW corner and along the western arm of the creek system.
DESCRIPTION: This Reserve consists of She-oak/Jarrah/Marri Woodland, on hillsides surrounding wide floodplains dominated by sedges & shrubs. .
In the woodland parts of the reserve, the largest trees are 0-20m tall ucalyptus marginata (Jarrah), Allocasuarina fraseriana (She-oak) and Corymbya callophylla (Marri). Common understory tree species are Banksia grandis, Banksia attenuata, Nuytsia floribunda, and ucaluptus staeri. The shrub layer includes many Xanthorrea priessi, Kingia australis, several Hakea species, Jacksonia horrida, Isopogon spp, Agonis hypericifolia, Acacia webbii Gompholobium confertum, Anarthrea scabra
2 The woody hills divide the arms of the creeks which flow through wide, open sedgeland dominated by Meeboldina scariosa, Adenanthos cuneatus , Banksia serra, Calitris, Acacia hastulata, Banksia brownii. In the lower section, the creekline runs thru stands of Melaleuca raphiophylla, Taxandria linearis, Leptospermum drummondi, L. squarulosa?, Callistemon, vandra aristata, Astartea fascicularis, Nuytsia floribunda, Jacksonia horrid.
Melaleuca thicket
3 The western arm of the creek forms a large body of water in the lower section. This area appears to be permanently flooded and the deaths of the Melaleuca raphiophylla suggests that the flooding regime has altered at some stage.
There are several Declared Rare Flora & Priority listed species occur in the reserve. They are not able to listed in this report, under DEC secrecy provisions for the protection of native plants.
A large proportion of the native plant species in this reserve are known to be susceptible to Pc. Species at risk include Banksia grandis, Banksia attenuate, Banksia illicifolia, Banksia quercifolia ,Xanthorrea preisii, Banksia sessilis, Hakea sp, , Adenanthos cuneatus, ucalyptus marginata,Allocasuarina, Jacksonia horrida, Gompholobium confertum, Andersonia caerulea and more
The loss of these species throughout the reserve will radically alter the structure of the plant communities and their habitat value.
DIEBACK
Dead Banksia grandis in woodland
Phytophthora cinnamomi is already present throughout most of the reserve, particularly in the lower areas along the creeklines and floodplains. Most of the reserve is currently recovering from a recent fire (2005?), and dieback impact is apparent. Areas recovering from fire events are generally considered “ uninterpretable “ by Dieback Interpreters, but in this case there is already ample evidence of the continuing impact of Pc. The combination of increased soil temperatures post fire and wet soils (as occur in the wet soils of the floodplain), can
4 create favourable conditions for the rapid spread of Pc throughout an area. This may be what has occurred here, with many recent deaths of susceptible species Recent Indicator Species Deaths were observed along the NW fire trail and up-slope of the floodplain , as well as in the flood plain and along the southern boundary of the reserve eg dead Banksia grandis, Banksia attenuata, Jacksonia horrida, Xanthorrea priessii, Banksia brownie
There were scattered indicator species deaths throughout most of the reserve, although the NW portion of the reserve seemed to be free of Pc
Pc may have been introduced to the reserve during construction or maintenance of the fire access trails , or possibly just through water flow from the catchment of the creeks. DEC Albany would have more information on the history of the Reserve, as well as a more detailed survey of Pc occurance (see map below). Due to the presence of so many Declared Rare Flora, there is probably already a species recovery plan for this reserve which may include a phosphite treatment program.
EEDS: Despite the heavy impact of dieback, most of this reserve is native vegetation in good condition. There has been little disturbance in the interior of the reserve, and no weeds were observed along the interior fire access trails.
The only occurrences of weed infestations were : . Typha orientalis in 3 patches along the middle section of the southern creekline floodplain. The largest patch is 0.5 ha in size, a smaller patch (0.2 ha) 50m west and another smaller patch 00m further west.
5 Recommendation: Typha has the potential to invade large areas in seasonally inundated floodplains such as this one. Spreads by seeds blown in wind so it is important to remove all seed heads before they mature and seed starts to disperse. This should be done annually, before the seed-heads ripen , to contain the infestation and to prevent new infestations occurring. If the area is naturally flooded each year, slashing the typha just before the water returns can ‘drown’ the roots of the plants and reduce the degree of infestation. GPS Co-ordinates for the typha infestations are:
(50 H 057444 , UTM 6 4 650), (50 H 057523 , UTM 6 4 533),(50 H 0575 93, UTM 6 4 555)
A grassy area in the Melaleuca raphiophylla stands in the lower section of the western arm of the creek. Several Rough Tree Ferns (Cyathea cooperi ), are growing on the banks of the creek in this section. There are also some Inkweed (Phytolacca octandra) and nightshade (Solanum sp)in this area. The grass growing here is Yorkshire Fog (Holcus setiger) and is grazed by kangaroos. GPS Co-ordinates: (50 H 0576486, UTM 6 40994)
Recommendation: This site is difficult to access, but it would be possible to remove the nightshade and inkweed as these infestations are relatively light. Hand removal is suitable for many weed species and for small infestations. Herbicide treatment of weeds could be used as part of an integrated weed management approach. The tree ferns could be killed and left in situ using glyphosate (with surfactant) sprayed on the stems. The grass (Holcus setiger) is quite extensive thru this area and is grazed by kangaroos etc. Herbicide may be useful to kill weeds in high erosion sites, such as creek banks, leaving the root mass intact to help hold the bank together. However, as this site is a Nature Reserve with several rare flora species (and possibly fauna species), we would not recommend the use of potentially damaging herbicides in this instance.
*NOTE: The water in the creek here has a soapy and salty taste, which seems unusual for a freshwater stream in a nature reserve. We would suggest testing of water
6 samples for presence of chemicals used in neighboring tree plantations and farms, to determine if the surrounding land use is affecting flora and fauna in the reserve
Prickly paddymelon (Cucumis myriocarpus) on firebreak between Millbrook Reserve and neighboring Bluegum plantation.
The southern boundary of the reserve adjoins Bluegum plantations separated by a 0m wide firebreak and a dilapidated fence. Some parts of the plantations are heavily infested with weeds, particularly Inkweed (Phytolacca octandra.) Weeds are beginning to spread into the reserve along southern boundary, inkweed (Phytolacca octandra), nightshade (Solanum sp) ,fleabane (Conyza sp), Afghan melon(Citrullus lanatus), Prickly Paddymelon (Cucumis myriocarpus) GPS Co-ordinates: (50 H 0575995, UTM 6 40664)
Recommendation: Hand removal of isolated Inkweed (50 H 0576534, UTM 6 40675) that has spread from the plantation. Regular control of weed species along southern boundary to prevent escape of weeds into the reserve.
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