In Djaara country, we are just coming into Wurrumuk and Dhurung time – Long-necked Turtle and seed time. As the weather continues to warm in the early summer period, Long-necked Turtle is laying its eggs, while native grasses are producing masses of seed across the landscape (see the Dja Dja Wurrung Seasonal Calendar here).
Kangaroo Grass (Themeda triandra) at Happy Valley, Castlemaine
Grasses are often over-looked and under-appreciated, but they play a major role in our ecosystems. They not only provide food for grazing mammals such as Eastern Grey Kangaroo, but they are also host plants for thousands of insects. These include many moths, whose larvae feed on the roots of grasses, and some butterflies, whose larvae feed on the leaves. The seeds of grasses are also a protein-rich food source for many of our birds, including red-browed finches and diamond firetail.
The Marbled Xenica – the larvae of this species feed on native grasses such as Tussock-grass (Poa spp.) and Kangaroo Grass (Themeda triandra).
Grasses also help to sequester carbon and reduce soil erosion. Most of our native grasses are perennial, so they are generally deep-rooted and do a great job at holding the soil together. This contrasts to many of the annual grasses that have been introduced for agriculture, which tend to die back over spring, leaving the soil exposed and bare over the hot summer months.
There are two broad types of grass, called C3 and C4. The C3 grasses predominantly grow over the winter-spring period and include some of our most diverse genera such as Spear Grass (Austrostipa), Wallaby-grass (Rytidosperma) and Tussock-grass (Poa), as well as Weeping-grass (Microlaena stipoides) and Wheat-grass (Anthosachne scabra). The C4 grasses evolved more recently in response to drying across planet Earth and have adaptations that allow them to conserve water. These species don’t begin their main growth phase until mid-spring, continuing to grow over the summer period. C4 grasses in our region include Kangaroo Grass (Themeda triandra) and Red-legged-grass (Bothriochloa macra).
Identifying different grass species can be tricky but is well worth the effort. Once you start looking closely, you will find that each species has different types of seeds that distinguish it from others. A small hand lens will enable you to see these seeds up close, or a step further is to invest in a stereo microscope, many which now have cameras that can take great macro photos.
Different species of Wallaby-grass (Rytidosperma spp.)
So if you can spare some time in the next few months, get out in the Box Ironbark and check out some grasses, you will be amazed at what you find! Many of our native grasses are also easy to grow, require minimal watering and can look spectacular in the garden.
Native garden in Castlemaine dominated by Common Tussock-grass (Poa labillardieri)
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