Our mid-October monitoring day is warm and calm, though clouds come over later. Warm enough for reptiles to appear - we see a Bearded Dragon and a Blue-tongued Lizard ambling through unburnt undergrowth. The dragon’s colouring, with yellowish 'beard' against grey body, provides particularly effective camouflage by matching the dried-out understorey colours. We haven’t seen these lizards before here - We hope they are residents rather than unwilling immigrants from elsewhere.
After the September fire, we are keen to see how the woodland plants have responded. We joined three Crested Pigeons in the area blackened by the fire; they are foraging on the ground, whereas we are checking for a wider variety of plant responses. Grasses do not seem to be flourishing, and in fact local reports suggest that those that resprouted early after the fire may have been grazed back by rabbits. However, we count at least 15 herb species resprouting. Plantago gaudichaudii resprouts are developing buds already, six weeks after the fire, while the trailing pea Desmodium brachypodum is suffering from herbivory. Resprouting plants amass biomass and flower faster than seedlings, giving them an advantage, although grazers are attracted to burnt areas with lots of new growth.
Interestingly, seedlings of some of these resprouting native species are also appearing in the burnt areas, particularly Dichondra repens, which is common throughout the woodland as a ground-hugging creeper. Its seeds don’t normally germinate easily, and it will be interesting to see whether it is heat or smoke that causes this germination response to fire. Even though Dichondra repens can survive and proliferate vegetatively, germination is needed to start a new generation.
Unfortunately some weeds are taking advantage of the cleared, ash-fertilised burnt areas too - there are lots of tiny seedlings of *Sida rhombifolia, Paddy’s Lucerne, and some of *Cirsium vulgare, Spear Thistle, and *Modiola caroliniana, the Red-flowered Mallow. However, fire may be useful in fighting the most troublesome weed, African Olive. We’ve tagged some young plants that seem to have been killed by the fire, and will keep a watch on them to see whether or not they recover.
The unburnt woodland has a pale brownish hue, largely from dead leaves and old inflorescences of some of the grasses. These not only look dead, but crunch underfoot. Lots of plants die back at this dry time of year, and resprout when conditions are better for growth. There are quite a few varieties on the theme of rootstocks for this purpose – thickened taproots, rhizomes (underground stems), fleshy tubers, corms and bulbs. It is thought that resprouting rootstocks may have developed initially as a response to drought, but now enable such plants to survive fire. Rainfall is lower in western Sydney than on the coast, and underground storage organs are a common characteristic of plants growing in the shale-based soils of the Cumberland Plain; this is reflected in the collective name for Aboriginal people of this area, Dharuk, meaning yam or tuber.
Occasional new inflorescences have appeared on the grasses, Themeda triandra, Bothriochloa macra, Austrodanthonia racemosa, Dichelachne micrantha, and Microlaena stipoides. And some of the herbs are flowering, though not in massed proportions – blue Ajuga australis and mauve Brunoniella australis. On Indigofera australis shrubs, seed pods are developing where sprays of pink flowers were in early September. The tiny sedge Carex breviculmis, noted flowering previously, doesn’t seem to have been so successful in forming seeds.
A long flowering season may be a characteristic that makes some weeds successful, and *Anagallis arvensis, *Hypericum perforatum, *Linum trigynum, *Medicago lupulina and *Verbena bonariensis are certainly quick off the mark with flowers this spring. *Senecio madagascariensis flowers are present too – but then, there have been yellow flowers of this weed in the woodland all through winter. (2001)
Asterisk * indicates exotic species naturalised at the Australian Botanic Garden.