In early Spring, we finally made a visit to Mt Imlay, a long-held ambition ever since we first arrived here. Mt Imlay (886m) dominates the skyline from Merimbula to the Victorian border and is accessed via Burrawang Rd, 20 km (15 mins drive) south of Eden, on the Far South Coast of New South Wales. Here is a photo of the National Parks map: It was named after the Imlay Brothers, who settled in this region in the 1830s and 1840s, establishing a huge pastoral, whaling and trading empire. It was known to the local aborigines as ‘Balawan’ and is a place of spiritual significance for them. Apparently, it was used as a site for telepathic communication with groups to the north near Wallaga Lake. The foothills were selectively logged in the 1960s and a fire trail was built to the summit, giving access to the trig station, but the track was closed in the 1970s to allow the area to revegetate. There is also a Telstra Sea Phone facility, built in 1994 and serving as the last communication link between Melbourne and Sydney for coastal vessels. In 1972, 3808 ha of steep, heavily forested country around the peak was reserved as Mt Imlay National Park, which has since been extended to 4822 ha. The park has a variety of habitats and is an important refuge area for the conservation of the local native flora and fauna, including a number of threatened or geographically significant species. The summit is of particular scientific interest because of its predominantly undisturbed nature, the presence of several threatened plant species and its biogeographical similarity to Tasmanian peaks. I will be describing our walk soon, but first some introductory notes about this beautiful national park.
Most of Mt Imlay National Park was formed during the Ordovician Period, 500 to 435 Million years ago, from sedimentary and metamorphosed rocks of the Mallacoota Beds, part of the Southern Highlands Fold Belt, including greywacke, sandstone and shale. The summit of Mt Imlay and the upper slopes are younger, with Devonian (395 to 345 Million years ago) rocks of the Merimbula Group, lying above the Ordovician sediments. The Merimbula Group includes sandstone, conglomerates, quartzite, siltstone and shale. Quaternary sediments form narrow river flats along the Towamba River on the northern edge of the park. The soils on the summit and ridges are shallow with many rock fragments and the upper slopes are very sandy, loose and very erodible and subject to movement. I always marvel at the tenacity and optimism of seedlings growing in rock! The summit area is only small and drops steeply in all directions with cliff lines in the north and east and a series of steps on the western slope. These steps are formed by the differential erosion of the alternating bands of sandstone, conglomerate and shale. Ridgelines extend from the summit, dissecting the rest of the park, which has narrow rocky ridges and deep gullies, as seen in the photo below.Vegetation
The ridges and dry lower slopes are covered by open forest, dominated by Silvertop Ash, Eucalyptus sieberi and also includes Yellow Stringybark E. muelleriana and occasionally E. globoidea and Blue-Leaved Stringybark E. agglomerata. The understorey is shrubby and includes Native Cherry Exocarpos cupressiformis, Hickory Wattle Acacia falciformis, Shiny Cassinia Cassinia longifolia, Tetratheca thymifolia , Narrow-Leaf Geebung Persoonia linearis, Acacia obtusifolia , Prickly Broom-Heath Monotoca scoparia , Smooth Geebung Persoonia levis, Banksia collina, Bedfordia arborescens, Hakea macreana, Mountain Speedwell Derwentia perfoliata, which had just finished flowering when we visited, and Hibbertia saligna, which is regionally uncommon and at the southern limit of its range. The steep south-east facing slopes (especially just below the ridge crest) are covered by stands of White Ash, E. fraxinoides, a species with a restricted distribution.
The moist sheltered gullies and slopes support a tall open forest of Yellow Stringybark, Monkey Gum E. cypellocarpa and River Peppermint E. elata, with a shrub layer of Hop Goodenia Goodenia ovata , Blue Olive-Berry Elaeocarpus reticulates, Lance Beard-Heath Leucopogon lanceolatus and Fireweed Groundsel Senecio linearifolius.
There are also pockets of rainforest, including Black Olive-Berry, Elaeocarpus holopetalus, Banyalla Pittosporum bicolour, Soft Tree-Fern Dicksonia antarctica, Hard Water Fern, Blechnum wattsii and Pomaderris species, including Pomaderis phylicifolia subsp. ericoides.
Other ferns include: Maidenhair fern Adiantum sp (Photo 1); Bracken fern Pteridum esculentum; Coral Fern Gleichenia rupestris (Photo 2); and Rock Felt Fern Pyrrosia rupestris (Photo 3). Climbers include Austral Sarsparilla, Smilax australis, which is shown in the first three photos at various stages and Drooping Mistletoe, Amyema pendula (Photos 4 to 5).On the rocky summit is a woodland, dominated by Narrow-Leafed Peppermint, Eucalyptus sp. aff. radiata, but also including Silvertop Ash and Messmate E. obliqua. There is also a stand of less than 200 trees of the very rare, endemic Mallee Gum, Eucalyptus imlayensis, which emerges from a closed tall heath, containing Leptospermum scoparium (1st photo below), Scented Paperbark, Melaleuca squarrosa, Mat Rush Lomandra longifolia, Sunshine Wattle Acacia terminalis (2nd photo below), Prickly Broom-Heath Monotoca scoparia, Common Oxylobium Oxylobium arborescens, Boronia pinnata and Hibbertia dentata. Other plants we saw on our walk included: Hairpin Banksia Banksia spinulosa (photo 1), Old Man Banksia Banksia serrata (photo 2), and plenty of flowering Epacris impressa (photos 3 and 4), which was quite spectacular!The Imlay Mallee is only found at a single site on the steep rocky east-facing slope at an altitude of 850m to 870m. It grows to a height of 7 metres and is multi-stemmed with smooth orange-brown and grey bark, which is shed from the stems in ribbons. Seed production is rare and there are no juvenile plants recorded. Mallee Gum appears to be related to Tasmanian eucalypts, an association backed up by the presence of Eriostemon virgatus, which normally grows in Tasmania, Mt Imlay being one of the few mainland locations of this shrub. Known by its common name, the Tasmanian Waxflower, it is the only four-petalled Eriostemon in Eastern Australia. The Weevil Aterpus kubushas, also found in Tasmania and the Victorian Alps, has also been collected on the summit, further evidence of Mt Imlay’s biogeographical similarity with the Tasmanian peaks.
The summit of Mt Imlay also has a number of threatened and biogeographically significant plant species including: Pomaderris costata, Persoonia brevifolia (close to northern limit), Monotoca elliptica, Saw Sedge Gahnia subaequiglumis, Prostanthera walteri, and Leafless Pink Bells, Tetratheca subaphylla, seen in the photo below. We enjoyed seeing the early Spring blooms of another endangered endemic species, Boronia imlayensis, seen in this photo. It had only just started flowering on our visit in late August. We could not identify this shrub- perhaps someone could help us?Recent mapping of the park revealed that half of the park is fragmented old-growth forest, whose hollows provide essential habitats for all the arboreal mammals.Fauna
Native mammals include: Red-Necked Wallaby, Swamp Wallaby, Greater Glider, Brush-Tail Possum, Eastern Pygmy Possum, Platypus, Wombat, the Large-Footed Myotis and Bush Rat. There are three threatened species: the Long-Nosed Potoroo, the Koala and the Tiger Quoll. Native birds recorded include: the Gang-Gang Cockatoo, the Superb Lyrebird, the Little Eagle, the Wedge-Tailed Eagle, the Wonga Pigeon, Common Bronzewing, Yellow-Tailed Black Cockatoo, King Parrot, Grey Currawong, Little Lorikeet and Red-Browed Finch. Reptiles include: Red-bellied Black Snake, Brown Snake, Lace Monitor and Cunningham’s Skink.And now to our walk, as seen in the National Parks map above! From the Princes Highway, a 20 minute (10 km) drive up the gravel Burrawang Rd through the East Boyd State Forest with dramatic examples of the devastation of clear felling practices along the way , as well as revegetated areas from 1977 and 1978, brings you to the Burrawang Picnic Area and the start of the Mt Imlay Summit Walking Track. At the start of the walk and the last stretch to the summit are Boot Cleaning Stations with an information board (seen in the 2nd photo), to stop the spread of the Cinnamon Fungus, Phytophthora cinnamomi. These include a brush to clean your boots and a dip with a chemical solution to wash your soles. Already, a number of species have been affected including the Austral Grass Trees, Tea Broom-Heath, Common Heath, Leafless Pink Bells and Hairpin Banksia. The fungus attacks the roots and causes them to rot and has already destroyed large areas of Grass Trees in particular.The track is described as a challenging 3 km walk, rising 600 m to the summit (6 km return; 3 to 4 hours), but because the walk is broken up into different sections and there is so much botanical interest, we managed it quite easily with photography stops along the way. Also, I think we are fairly fit, as our daily walks in Candelo involve steep hills either side of the valley, and we weren’t even stiff the next day. I was very impressed with my usually suspect knee, which behaved beautifully on the walk with not a twinge of pain! The walk follows the ridge up the right hand side of the mountain, shown in the photo below. The track is marked by silver tags on the trees and there are interesting information boards at intervals. The first stretch of the track is a bit boring through dry open eucalypt forest along the old road, but once you reach the Austral Grass Tree (Xanthorrhoea australis) ridge, it becomes much more interesting. We ascended a steep path past Dianella tasmanica outcrops (photo 2) to our first set of large boulders. We skirted around a natural amphitheatre on the same level, then ascended to the base of a cliff with huge boulders under a tall forest of Silvertop Ash trees. A steep slope leads to a razorback ridge, which runs 500m to the trig station. There were lots of Spring wildflowers in a variety of colours- whites, creams, yellows, pinks, blues, purples and reds. Here are a few more photos. In order: Eriostemon virgatus, Lance Beard-Heath Leucopogon lanceolatus , Hakea macreana, Pomaderris phylicifolia subsp. ericoides, Sweet Wattle Acacia suaveolens, and Common Heath Epacris impressa (last two photos). The stunning photo opportunities were further increased by the spectacular views of the coast, north to Mt Dromedary (photos 1 and 2) and Eden, including the wood chip mill (photos 3 and 4); west to the mountains (photos 5 and 6); east to Green Cape and Bay Cliff and the Wonboyn River (photos 7 to 10); and to the far south, the holiday shacks, beaches and river entrance at Mallacoota (photos 11 and 12).Unfortunately, the day was a bit cloudy and grey and the summit quite cold and windy, so we ate a quick picnic lunch at the top, disturbing a roosting Little Eagle in the process. Then descended back to the Silvertop Ash forest, where we met the only other bushwalkers we saw that day- a couple with a six year old daughter, whose timing was better as the sky had just turned a bright blue for their arrival at the summit. Their views would have been even better! These photos contrast our day (photo 1) and that of the next couple (photo 2). We really enjoyed visiting this iconic local landmark. Next week, we explore the Merrica River, another stunning walk in Springtime. I will finish with a lovely photo of the stump of a dead Austral Grass Tree, which captured our attention!