- Laced Fritillary
- Rusty Pomaderris and the Jewel Butterfly
- Edge Senna, Small Grass-yellow and Yellow Migrant
- Coastal Caper - host to five species
- Blue Tiger
- Richmond Birdwing
- Love Flower (Pseuderanthemum Variabile)
- Hedge Grasshoppers and Fireflies
- Local Efforts
Brisbane Forest Park catchments have a long history of naturalist excursions since settlement.
On July 16th 1887 the Field Naturalists section of the Royal Society held their twenty-first excursion. This excursion started at the gates of the Toowong Cemetery and followed the gullies of Ithaca Creek up Mount Coot-tha.
One of the plants they recorded was the Arrowhead Violet (Viola Betonicifolia). This small herb is the host plant of the Laced Fritillary Butterfly.
The Naturalists made no mention of this butterfly being present at the time but, years later, in 1916 it was captured by a young boy at nearby Indooroopilly.
Another excursion to this catchment on January 5th 1889 did not record this plant.
The excursion report writer did note that "a great deal had been cleared" and "the collecting ground of former excursions was therefore very much curtailed".
It is not often that the demise of a particular species is documented. It shows that the process of the disappearance of the Arrowhead Violet in this catchment started quite a long time ago.
And now, many years later, the Laced Fritillary Butterfly that depends on this violet has become critically endangered.
Rusty Pomaderris and the Jewel Butterfly
Another plant that has almost disappeared from the catchment is Rusty Pomaderris (Pomaderris Ferruginea).
This year I could only find three plants on the eastern slopes of Mount Coot-tha, down from five last year. A few more occur on the western side.
This attractive plant is the host of the Yellow Jewel Butterfly. There are now not enough plants to support the butterfly. While I have found no records that it occurred in this catchment, there is a specimen in the DPI collection labelled Mount Gravatt 1901 so it may have once occurred in this area as well.
Edge Senna, Small Grass-yellow and Yellow Migrant
The Edge Senna (Senna Acclinis) is a rare plant found above Enoggera Dam and in other parts of Brisbane Forest Park.
It is a special plant because, not only do two species of butterflies breed on it, the Small Grass-yellow (Eurema Smilax) and the Yellow Migrant (Catopsilia Gorgophone), it is also very bee friendly.
Teddy Bear, Carpenter and Blue-banded bees can be seen frequenting the flowers, buzzing the stamens to release the pollen. These bees are now being studied for their usefulness in pollinating tomatoes (which also need to be buzz pollinated) in greenhouses. Finding a native bee for the purpose is important to prevent the importation of foreign bumblebees.
Coastal Caper - host to five species
One plant that still occurs in the catchment in sufficient numbers to support some butterflies is the Coastal Caper (Capparis arborea once known as Capparis nobilis). Some fine specimens can be found in the Banks Street Reserve. While the mature trees look similar to an Orange tree, young plants are heavily protected by sharp spines. Suckers frequently appear around the parent tree. These patches provide safe nesting sites for small birds.
The Coastal Caper is host to five species of butterflies - the Caper White, the Caper Gull and three species of Pearl Whites. It is thought that Bouloumba Creek in the Connondales means place of white butterflies. The mainly white butterflies associated with the Coastal Caper are certainly common in that locality.
The Caper White butterfly is well known for its migrations. Vast numbers of this butterfly could be seen heading north recently in October. Later in the season descendents of those butterflies, that are lucky enough to find host plants, can be seen heading south. There are substantially fewer numbers of these subsequent generations and this return migration often goes unnoticed.
Another butterfly that also migrates in vast numbers, firstly in a south then later north direction, is the Blue Tiger. Because there are now not as many host plants Corky Milkvine (Secamone Elliptica) for it to breed on in the Brisbane area, only low numbers make it back later in the season.
Corky Milkvine is often found in Hoop Pine forests. I have not yet found it growing naturally below Enoggera Dam though it does occur in Brisbane Forest Park. This plant has silky wind blown seeds and, therefore, could be expected to turn up anywhere. The vine gets really hammered by the caterpillars during the migration, but it has a secret weapon. The tiny flowers which are produced in profusion are not pollinated by bees, but by Tachinid flies. These flies parasitize the caterpillars which eat the leaves. As the Tachinid fly populations build up, eventually they reduce the numbers of caterpillars. The flies in their turn become food for insect eating birds.
The Richmond Birdwing butterfly is another that often migrates. One particularly famous migration led to the appearance of many butterflies in the streets of Brisbane in 1870. However, I could find no records of any natural breeding in Brisbane or in Brisbane Forest Park. There are no herbarium records of its host plant, Coastal Birdwing Vine (Pararistolochia Praevenosa) occurring in the park, even in the rainforest of Mt Nebo or Mt Glorious.
There are records of birdwings breeding on plants grown in gardens in Brisbane. Lately this butterfly has become rare because the young caterpillars need very soft growth to start feeding on. Due to the drought most garden grown plants have only older, tougher leaves. Birdwing vines grown along creek-lines and close to permanent water should be able to avoid this problem.
Love Flower (Pseuderanthemum Variabile)
Understorey plants are often the most neglected but are important for maintaining biodiversity. One species in particular, the Love Flower (Pseuderanthemum Variabile), supports a number of butterflies. This includes the Leafwing; the others are the Varied, Danaid and Blue-banded Eggflies. A massed groundcover of this species can be very attractive when in flower. Flower sprays are eaten by Bearded Dragon Lizards.
Some plants are especially useful for a wide variety of animals. Native Mulberry (Pipturus Argenteus) is a host for the Speckled Line-blue Butterfly as well as the Jezebel Nymph. The Yellow Admiral and Varied Eggfly caterpillars are occasionally found on this plant. Many other insects feed on the leaves and become food for insect eating birds. Female trees produce a multitude of small white berries for six months of each year. These berries are eaten by many birds, most notably the Scaly-breasted Lorikeet.
Hedge Grasshoppers and Fireflies
The Hedge Grasshopper rarely eats grass, preferring the leaves of rainforest plants. The young grasshoppers start out on Love Flowers, Stinging Nettles and other understorey plants. Here they are food for lizards. As they grow larger they end up on Native Mulberry leaves. This tree is a fast-growing pioneer species, and so can support many grasshoppers. These then become food for the Crested Hawk and other large insect eating birds.
Fallen leaves, twigs, branches and even trees are very important in revegetation and regeneration projects because, as well as providing shelter, they become food for a great variety of fungi. These in turn are eaten by variety of different animals, including snails. In wet areas, small snails in the leaf litter become food for the larvae of fireflies (a type of beetle). These delightful creatures come out at dusk, usually when the Bladder Cicadas stop calling. They fly around for a short period, blinking their lights and looking for mates, before they too retire for the night. I have seen them near the section of Enoggera Creek where it is crossed by Illowra St.
Given the reducing biodiversity and local efforts such as SOWN's to improve the situation, it is worthwhile contemplating large scale approaches also. For example, the famous Kew Royal Botanic Gardens has a scheme to collect seed of a significant sample of the world's estimated 420,000 plants. It is called the Millennium Seed Bank Project.
It is certainly important to preserve our plant biodiversity. Hopefully it won't need to be used because any plant brought back from the brink of extinction would be very lonely indeed, and may not be able to survive without all its associated wildlife. In this context local efforts are all the more important.