Our next morning Landcare working bees: Sunday 23rd May & Monday 7th June.
As we observed the floral
displays, often in miniature as is normal with many Australian species, it soon
became apparent that thousands of seedlings were colouring the ground green. Millions
of seeds have been “lying in wait” in the soil’s seed bank for the re-hydration
and warmth of Sprummer 2020–2021. The seeds germinated into an invasion of
weed species that swamped the native plants, visually and possibly biologically.
It was disheartening to realise
that we hadn’t “won the battle” against Paterson’s Curse. The sheer volume of weed
‘biomass’ meant that it was unwise and daunting to move into the wilder parts
of Mt Rogers without gaiters, snake bandages and a mobile phone. What weeding impact
could be achieved when we couldn’t see where we were going or know where next
to tread?
As ever, the active Landcare
volunteers have enjoyed conversations with you, the Mt Rogers community, and
welcomed the hundreds of newcomers to the reserve met during the mostly co-operative
summer weather.
Our target species were Cootamundra Wattle saplings and Black Nightshade, Solanum nigrum (shown in this photo).
Acacia
baileyana (Cootamundra Wattle) is local to the Cootamundra area and was widely planted before its
invasiveness became known. The attractive species also has a reputation for
being ‘short-lived’. Whilst this may be true it’s not characteristic of all the
700+ wattle species.
These trees provide pollen to
attract pollinators: the pollen and the seeds are food for a range of
species. Insects amongst the wattles’ foliage are eaten by small birds. Shelter
is provided for them and ant species nurturing the larvae of specific butterfly
species. Even when dead there are borers and other invertebrate larvae under
the wattles’ bark that feed strong-billed cockatoos. The birds can apparently
hear the hidden larvae. Perhaps they also see the signs of trees under stress.
Fire heats Acacia seed capsules, causing the pods to twist and release the seeds onto the ashy ground. Thousands of seedlings germinate. We’ve already been through the reserve's burnt areas several times pulling out the seedlings. Phil counted 353 during one of his pulling sessions. Pulling is easiest when the soil is moist, and it reduces the need to use herbicide. We cut down the larger saplings, very close to the soil. If left, the Cootamundra Wattles would create a monoculture with little space for other species. There are several other species of Acacias in the reserve’s 65 hectares ensuring the enrichment of soils and other plants’ healthy growth through their roots’ nitrogen-fixing properties.
The Nightshade plants’ berries (see the photo above) are attractive to birds, including Crimson Rosellas. We pulled the plants and made several large, dense piles, working on the principle that all their berries would fall in the same place if they did ripen (see next two photos). There are several native nightshade species occurring in southern Australia. Another Solanum, the Kangaroo Apple has attracted the attention of bush-walkers and foraging enthusiasts this Sprummer. Tomatoes, chillies, peppers, eggplant, tobacco and potatoes are useful relatives of the hundreds of invading Black-berry Nightshade plants we have piled up.
In previous years volunteers had
pulled out 6 wool bags of Mustard plants from this same area. TCCS crews
trucked the bags to the green-waste sites for composting at very high
temperatures. It’s heart-breaking for Landcare volunteers to see that there were
dozens of Mustard bags-full that we weren’t able to reach this Sprummer when
feral grasses and wild-oats grew to off-putting heights due to the rains. Butterflies
and other pollinators were able to find the pale-yellow Mustard blooms. The
cuboid seeds that result are about the size of an ‘o’, so you can imagine
how many seeds fall out of each plant’s ripening pods!
It’s easy to see how each species
flourishing outside of its normal range and beyond the reach of natural
controls can cause significant problems whilst simultaneously being beneficial to
both native and introduced animal species.
Where are the saving graces of
the ubiquitously invasive and detrimental African Lovegrass? I’ve heard
the species was introduced to stabilise creek banks. Ted has spent countless
hours on his daily walks daubing ALG tussocks by the hundred-fold, and Steve uses a
back-pack spray for infestations across the reserve. These major individual
and voluntary efforts are recorded to the Collector App by rangers of the ACT
Government’s Invasive Species unit. A contractor was employed by TCCS in February
to spray ALG along the paths and tracks of the reserve. It’s clear that this work
was thwarted by the rain and warmth that stimulated rapid growth of small or
newly germinated tussocks.
ALG is spread by mowing. The machines come into Mt Rogers in clean condition, later moving to heavily infested areas
such as the Wickens Place carpark. The ALG seeds are tiny: imagine trying to
clean every seed out of the nooks and crannies of machinery. Footwear, paws,
wheels, wind and water also move seeds around.
The next morning Landcare working
bees: Sunday 23rd May & Monday 7th June.
I am fascinated by Kurrajongs.
They belong to an iconic family related to the extraordinary Bottle Trees. In
the reserve there are several, and they represent a good-news, bird-dispersal story, because the parent trees’ seeds are eaten elsewhere and pooed by birds perching on one
or other of ‘our’ eucalypts’ branches. I like to think that the main dispersal
species are the maligned Currawongs….a ‘nasty’ species doing some good. In
their large, boat-shaped pods, the Kurrajong seeds are surrounded by bristly hairs.
Indigenous people used to eat the seeds raw or roasted once these hairs were removed. The photo here shows two young Kurrajongs at Theodore.
It’s a bit difficult to describe where the Mt Rogers Kurrajongs are but there are two young ones growing outside the Hall Museum on Palmer Street. Inside there’s a display that includes Kurrajong seeds as the recent history of Halls Creek and Ginninderra’s first ‘European’ village is explained. Indigenous tools & artefacts from this region are there too. Opening hours: Thursday mornings and Sunday afternoons.
Rosemary,Convenor Mt Rogers Landcare Group.
6258 4724. 11.05.21.
