On the 8th March, Rainer Rehwinkel kindly offered Field Naturalists the opportunity to join a ramble that he was leading with his Lawson Landcare group.
In morning drizzle, the ramble started from a diverse grassland site situated between Dawn Cres and the former Naval facility at Lawson. Here, Rainer discussed grassland ecology. He pointed out that this grassland was more than the observed native grasses, such as Kangaroo Grass Themeda triandra, wallaby-grasses Rytidosperma spp., Red-legged Grass Bothriochloa macra and Windmill Grass Chloris truncata. It contained grassland forbs, some of which were in flower, and also blue-green algae and symbiotic lichen. Our discoveries included the Blue Devil Eryngium ovinum, Scrambled Eggs Goodenia pinnatifidia, Tufted Bluebell Wahlenbergia communis, New Holland Fuzz-daisy Vittadinia muelleri , Common Everlasting Chrysocephalum apiculatum and Grassland Morning-glory Convolvulus angustissimus. Rainer also talked about the interaction of grassland fauna, telling us that the previously-thought single species of Grassland Earless Dragon has now been split into four. The local Canberra species Tympanocryptis lineata can conceal itself in spider holes, which are thought to be holes initially constructed by crickets and then occupied by wolf spiders.
Furthermore, Rainer gave us some historical context of land tenure and details of ensuing conservation efforts. To help conserve this patch of natural grassland, ACT Government departments will remove recent well-intentioned, but inappropriate, tree-plantings, spray weeds, erect conservation bollards and draft a plan of management to implement a more sympathetic mowing regime, so that flowers are not lost before seeding. These outcomes are thanks to Rainer’s negotiations with the ACT officers, with help from MLA Jo Clay. Regarding the bigger picture, these grasslands have connectivity to a more extensive area of grassland in the former Naval facility at Lawson. Defence Housing had plans for extensive development, which have been reduced, again in part thanks to advocacy from Friends of Grasslands and the Conservation Council. The final outcome has still to be determined.
As mentioned, weeds are an on-going issue. It wasn’t hard to spot invasive species such as African Lovegrass Eragrostis curvula, Serrated Tussock Nassell trichotoma and St. John’s Wort Hypericum perforatum. Active management will be required.
Leaving this grassland, we followed a connectivity corridor between the former Naval facility and new urban development to a woodland. It was densely planted in the 1980’s with native species to form forest structure. It is now starting to mature, but is still sorting itself out to a woodland structure, which may not even be the end-point on soils suited to natural grassland. In the plantation we found a carpet of moss and a hatched Praying Mantis egg sack.
After the woodland, we walked down to a secluded part of the Lake Ginninderra shore. This is where we were shown the highlight of the day – one of only three known locations of the endangered Ginninderra Peppercress Lepidium ginninderense. This sub-population was recently discovered by Rainer. It is a disturbance species, and with succession, has possibly disappeared from the initially discovered patch at Lawson only to emerge on a track some tens of metres away.
Along the way, we encountered several bird species. A flock of Little Corellas flew over the grassland, then in the woodland canopy there was a flock of Weebills. At the Lake Ginninderra shore we saw three Wedge-tailed Eagles high in the sky, then back at the grassland a Nankeen Kestrel was observed swooping down to catch prey. A few Welcome Swallows also perched nearby. It was a bit cool and damp for butterflies, but several late-season female Common Browns passed us by, and a few Common Grass-Blues were flitting through the grassland.
After the walk, an impromptu table appeared, full of shared plates for morning tea.
We were all so appreciative of the very informative and enjoyable morning facilitated by Rainer.
– John Stein
