Species of the Month

Species of the Month: December


Chocolate Lily (Arthropodium strictum)

Credit: http://www.marion.sa.gov.au/webdata/resources/images/Arthropodium-strictum.jpg

Credit: http://www.marion.sa.gov.au/webdata/resources/images/Arthropodium-strictum.jpg

Scented flowers are often high up on the suburban gardener's wish list. Roses often take centre stage, complemented by gardenias and magnolias, and bordered by lavender bushes. However, there are numerous indigenous scented shrubs and flowers that Melbournians can plant if they wish to maintain their scented garden while helping to support native wildlife. The Chocolate Lily (Arthropodium strictum) is such a plant. A small, grassy looking plant, this purple lily will brighten up any garden, and its scent is delectable. Also known by the name of Dichopogon strictus, the Chocolate Lily is indigenous to a vast majority of Melbourne.

Lilies are fleshy perennials with tuberous roots and appear to have six petals, but in truth they have three petals and three sepals. Sepals are not true petals, and typically act to protect the flower before it has bloomed, but in several plant groups the sepals are colourful and act as petals. The flowers of the Chocolate Lily are three centimetres wide and are violet in colour, and are produced singly on erect stalks up to one meter tall. The petals are broad with undulating, ruffled margins, while the sepals are strap-like and curl backwards. Chocolate Lilies can be found flowering in September through until the end of the calendar year. Lilies are monocots, which means that their leaves have parallel veins as opposed to the veins that you find on the leaf of a dicot (for example, a eucalyptus tree), which form a complex network. The leaves of the Chocolate Lily are flat and narrow, and can grow up to 60cm long and 10mm wide. The Chocolate Lilies defining feature is its scent. You might have guessed from its name: the Chocolate Lily does, in fact, smell like Chocolate!

Chocolate Lilies are found in full sun and part shade, and thrive in well-drained soils. These lilies populate a wide range of woodland and forest habitats, from box ironbark forests and grassy dry forests to damp forests and swampy woodlands. This species is frost and drought tolerant, and is relatively adaptable, in the sense that it can survive in varying conditions. This species is rarely found in mallee regions and is completely absent from Victoria’s alpine region, but is found throughout much of Victoria’s woodland and forest ecosystems. National parks in which Chocolate Lilies can be easily found include Lysterfield Park, Organ Pipes National Park, Langwarrin Flora and Fauna Reserve and Westgate Park.

Chocolate Lilies will die back to the rootstock after they have finished flowering, will remain dormant throughout the summer, but then reshoot after the autumn rains. This species is pollinated by a range of insects, but does not attract birds or butterflies.

This plant is ideal for anyone who loves both gardening and cocoa-flavoured treats. If this sounds like you, head down to you’re nearest indigenous nursery and pick up a few for the garden, you wont be disappointed!

Author: Emma Walsh


The Black Swan (Cygnus atratus

Credit: Christopher McCormack

Credit: Christopher McCormack

If you’ve ever been for a stroll around Albert Park Lake, been down to Swan Bay outside of Queenscliff, or visited another of our regions wetlands, than you might have found yourself staring at one of our country’s more peculiar waterbirds. Black swans are small as far as swan species go, but proportionally speaking they have the longest neck of any of the seven recognized species. 

These birds endemic to Australia have been turning heads for a long time. The Dutch were the first people from the Old World to see the birds when they came ashore in Western Australia, and they have since come to adorn the state’s emblem and the logo of the famous Swan Brewery. 

Prior to their discovery, the concept of the "Black Swan" had always been considered a mythical anomaly. Indeed, philosophers who argued that some truths are obvious and do not need to be proven would often support their contention with the concept that all swans are white. The discovery of a whole new species of black swans threw a spanner in the works, and would come to support those who argued that all truths require evidence. But while Europeans were astonished, the Black Swan had long been a familiar sight to Australia’s Aborigines – they made for good eating!  

They can have up to six eggs and are often very devoted parents. Pairs reaffirm their bonds and celebrate territorial victories by calling to one another, bowing their heads, and lifting their bills to the sky in a display known as a triumph. Males are typically larger than females, though overall the species shows little difference between the sexes - although, unlike most birds, males of the species do possess a penis! Possibly to aid in the transmission of sperm in an aquatic environment. 

Work done by the Mulder Lab at the University of Melbourne has revealed a number of interesting things about these birds. For example, while swans are often depicted as the epitome of monogamous devotion, about 1 in 6 cygnets are the product of mating outside of the pair. Also of interest is the white bill markings that adorn their red bills. Zoologist and artist, Milly Formby, found that these markings appear to play a role in social interactions and may be indicative of the dominance rank of an individual. The Mulder Lab continues to study these birds at Albert Park Lake, where they collar individuals for identification purposes. You can get involved by downloading the My Swan app and reporting collared swans that you see. Visit the My Swan website for more information.   

Credit: http://raoulmulder.org/research/

Credit: http://raoulmulder.org/research/

Author: Christopher McCormack

Species of the Month: November

Garden Skink (Lampropholis guichenoti)

Amongst the leaf litter lies an impressive creature; sleek and scaled, agile and alert, a formidable predator — although the latter is only of concern to small invertebrates! Measuring a mere nine centimetres, in length the Garden Skink (Lampropholis guichenoti) is possibly one of the most common skink species found within Victoria and most certainly within suburbia.

They are an attractive slender skink often with a copper to brown-grey upper body, a dark brown and a pale stripe running from head to tail along the sides of their body, and a cream coloured underbelly. The species may be found throughout most of the state, with the exception of the semi-arid regions to the north and west. The species occupies a range of tree-filled habitats; however, they have also become accustomed to modified human environments and may be found happily living within backyards amongst the suburbs of Melbourne.

Given its diminutive size and secretive behaviour, it is perhaps not surprising that this species is often overlooked. It is quite conceivable that many Melburnians may be cohabitating with Garden Skinks without realising. Nevertheless, the little guys play an important role in maintaining the ecological balance of natural systems, ensuring that populations of small invertebrates — which make up the bulk of their diet — are kept in check. This is particularly helpful if you happen to grow your own veggies, as the small skinks can aid in mitigating the negative effects of many terrestrial insect pests.

It doesn’t take much effort to employ the services of the Garden Skink either; simply by providing mulch for them to forage in or some rocks or logs for basking, you might be able to encourage this humble garden inhabitant to visit your backyard (although it is also important to ensure that cats and dogs that may harm Garden Skinks are kept at bay, as well as refraining from pesticide use). They are also a very interesting species to observe, particularly at this time of year. If one sits still and quiet in Garden Skink habitat, they are likely to be rewarded with an insight into the small reptile’s world. Up to a dozen or more may emerge from the leaf litter within a few metres of the observer where at first there appeared to be none. This is because Garden Skinks tend not to be territorial, instead favouring to spend energy foraging rather than expending energy on patrolling and chasing away intruders. Having said this, it is not uncommon to see fights erupt during breeding season — which is occurring at present — in which one individual will latch onto another’s torso and tumble about until its grip loosens. The reasoning for these disputes is not particularly well understood, but it is thought that it probably relates to hierarchical dominance and associated mating rights. If you sit still enough they may even come right up to you, but just remember to refrain from handling them, as they have a tendency to ‘drop’ their tail in high stress situations, which is not ideal as it requires a lot of energy for another to grow back.

So on warm days, keep an eye out for this remarkable little Aussie who may be calling your backyard home. Alternatively, if they do not appear to be present, perhaps consider making some of the small changes discussed to entice them into your garden.

                                                                                                                         Author: Nathan Gregory

 

Mountain Ash (Eucalyptus regnans)

 

The tallest flowering plant on the planet, Mountain Ash is a species that towers over its neighbours. With the botanical name of Eucalyptus regnans, this species is a member of the genus that dominates the tree flora of Australia. There are over 700 Eucalyptus species, with less than ten species occurring exclusively outside Australia.

Trees of this species can reach up to 100m tall, with anecdotal evidence suggesting that some trees can grow even taller. Mature trees can measure as much as 15m around the base. Mountain Ash grow tall and straight, often with branches present only beyond 30m above the ground. They have fibrous, brown-grey bark for the first 15m above the ground, beyond which the bark peels away in ribbons to reveal the pale, smooth bark underneath. If undisturbed, Mountain Ash can live for up to 500 years.

Mountain Ash usually grow in deep soils and are found in mountainous areas with high levels of precipitation. This means that Mountain Ash are usually found in cool temperate rainforests and wet sclerophyll forests. Mountain Ash forests can be found in the Dandenong Ranges, Strzelecki State Forest, Walhalla, and in the Otways.

Mountain Ash is unusual compared to many other eucalypts because it has evolved to survive in wetter environments. They produce up to three times the amount of leaf litter than other species. In addition, Mountain Ash possess no insulating bark and no lignotuber, which are both adaptations to minimise damage caused by fire. The excess leaf litter, the stringy nature of the bark and the oily leaves, in addition to the lack of insulating bark and lignotuber make Mountain Ash fire sensitive. Mountain Ash don’t shoot from epicormic buds after a fire, instead the release huge quantities of seeds, which fall to the ground and germinate in the ash-ridden soil below. This species flowers profusely between December and May.

Mountain Ash forests are environmentally significant for a number of reasons. They provide habitat for many species of our native fauna, most notably the Wedge-tailed Eagle (Aquila audax) and the Leadbeater’s Possum (Gymnobelideus leadbeateri). Old-growth mountain ash forests are most significant in this respect because mature trees develop tree hollows, which are essential to many species of mammals and birds that require hollows for nesting.

Mountain Ash is also economically important. It is a hardwood timber and is used extensively as a source of timber for flooring, furniture, and other construction purposes. In the twentieth century it was used in the production of newsprint. Mountain Ash is favoured in the logging industry in part due to its fast growth rate: individuals of this species can grow up to one meter a year.

As you would expect, the main threat to Mountain Ash forests is logging. Although Mountain Ash are not threatened as a species, old growth Mountain Ash forests only exist in small pockets due to extensive logging. As mentioned earlier, the complete loss of these old growth forests would have significant implications for many of our native faunal species. These ancient forest giants are an iconic and essential component of our cool temperate rainforests and wet sclerophyll forests. And given their lengthy lifespan, the history that our remaining giants have experienced is awe-inspiring!

Author: Emma Walsh

Species of the Month: October

Pobblebonk Frog (Limnodynastes dumerilii)

Credit: http://ashdown4628.clients.cmdwebsites.com/blog/wp-content/uploads/2012/03/Pobblebonk_02.jpg

Credit: http://ashdown4628.clients.cmdwebsites.com/blog/wp-content/uploads/2012/03/Pobblebonk_02.jpg

Named for its unusual call, the Pobblebonk Frog, also known as the Eastern Banjo Frog (Limnodynastes dumerilii) is common throughout our city's suburbs. You may find one in a backyard pond, or even in a garden bed while digging! 

The Pobblebonk is found throughout Victoria and Tasmania, but also west to Adelaide and north along the coast of New South Wales. One subspecies, L. dumerilii dumerilii is found throughout the northern and western suburbs of Melbourne, while L dumerilii insularis is found throughout the eastern and southern suburbs. Eastern Banjo Frogs  inhabit a range of environments, including woodlands, rainforests, farmlands, coastal areas and urban regions. These frogs live in and around the still water bodies found in swamps, dams streams and lakes. 

The Pobblebonk Frog can be up to 85mm long, often with a warty appearance that can cause them to be confused for the dreaded Cane Toad (Rhinella marina). They can vary greatly in colour, ranging from dark browns and blacks to olive green. Pobblebonks have a pale, yellow stripe from the eye to the top of the front leg and there may also be a pale stripe down their back.  This species lacks webbing between the toes, but has a shovel-like toe on each rear foot to aid them in burrowing. The most defining features of the Pobblebonk include a prominent tibial gland on the lower portion of each rear leg, and fleshy metatarsal tubercles  (fleshy lumps) on each hind foot.

Mating occurs from August all the way through to April. Females are able to lay up to four thousand eggs, which they deposit into a large, white, floating raft that made from mucous and bubbles. These rafts are usually found concealed in aquatic vegetation. Depending on water temperature (which affects metabolic rates), tadpoles can take up to fifteen months to fully develop. When they hatch, pobblebonk tadpoles are large, dark brown or black, with dark grey or brown fins.

This species of frog has a call that sounds like a plucked banjo string: a resonant ‘bonk’ sound. Nearly all year round these calls can be heard, especially after heavy rains. Males call every few seconds, usually from the shelter of floating aquatic vegetation, but also less regularly from the waters edge. During dryer spells, Pobblebonks will burrow themselves into the ground with their well equipped back feet, and wait for rain. 

Author: Emma Walsh


White Cypress-Pine (Callitris columellaris)

Credit: http://www.pfaf.org/Admin/PlantImages/CallitrisColumellaris2.jpg

Credit: http://www.pfaf.org/Admin/PlantImages/CallitrisColumellaris2.jpg

Many Melbournians are familiar with the ornamental juniper and fir trees that you find in many suburban gardens, or with the pine trees that we decorate at Christmas time. These are all foreign species, however there are a few gymnosperm species that are native to Victoria. Furthermore, there is just one gymnosperm that is indigenous to Melbourne: the White Cypress-pine (Callitris columellaris).

What is a gymnosperm I hear you ask? Gymnosperms are the primitive cousins of the flowering plants, the angiosperms.  They differ to flowering plants in that they do not produce flowers and instead produce cones, and that the ovule is not enclosed in an ovary. In species that are monoecious (hermaphroditic) individuals bear both male and female cones, while in dioecious species male and female cones are only found on individuals of their respective genders. Male and female cones are easily distinguished by their size: the male, pollen-producing cones are smaller than their female, ovule-bearing counterparts. Gymnosperms rely mostly on wind pollination, not insect pollination like many flowering plants.

There are four plant phyla that represent the gymnosperms, and by far the largest and most diverse is the Coniferophyta. Also known as conifers, members of the Coniferophyta are monoecious, deciduous (or evergreen) and have needle- or scale-like leaves. Some of the better-known conifer groups include the spruces, firs, pines and redwoods. Victoria is home to six conifer species, the Mountain Plum-pine (Podocarpus lawrencei), the Port Jackson Pine (Callitris rhomboidea), the Black Cypress-pine (Callitris endlicheri), the Scrub Cypress-pine (Callitris verrucosa), the Slender Cypress-pine (Callitris preissii), and of course, the White Cypress-pine (Callitris columellaris).

The White Cypress-pine (also known as Callitris glaucophylla) is a slender, conical tree with a single straight trunk with thick greyish bark and scale-like leaves. It’s female cones are relatively small and round, while it’s male cones are so small that they appear to be the dead ends of the leaves. The White Cypress-pine was originally widespread across Australia, but its distribution has been altered post-European settlement by domestic livestock and feral animal grazing, altered fire regimes and invasive weeds. Today its distribution is largely fragmented, with much of it’s Victorian range managed as forest reserves. White Cypress-pines are indigenous to the northern suburbs of Melbourne, namely Maribyrnong, Diggers Rest and Bulla. The good place to find the White Cypress-pine in its natural habitat is in the Organ Pipes National Park in Keilor North, northwest of the CBD.

This species is generally found in areas with sandy, well-drained soils. It does not survive in finer soils due to its susceptibility to water logging.  White Cypress-pines are extremely drought tolerant, and often develop fine ‘feeder roots’ in the upper few inches of soil for added water absorption. Although this species is hardy in dry conditions, it is sensitive to fire. Tree crowns will not regenerate and seed output can be suppressed for up to five years after being damaged by fire. Seedlings are also vulnerable to fire, as well as introduced herbivores such as sheep, goats and rabbits.

In the past aboriginal communities have used the timber of the White Cypress-pine to make spears, spear throws and paddles, and have mixed its resin with kangaroo dung to create an adhesive. It’s bark and foliage were also used as insect repellent.

It is easy to overlook conifers when considering iconic indigenous plants because they aren’t as pleasing to the eye as their angiosperm counterparts, but I find them fascinating because of the way they endure and persist in an environment where flowering plants are so dominant. White Cypress-pine is our ONLY indigenous gymnosperm, stoically holding its own against the countless angiosperms that call Melbourne home. 

Author: Emma Walsh

Species of the Month: September


Forest pollinators: the grey headed flying fox (Pteropus poliocephalus)

Image Credit: http://www.nationalparks.nsw.gov.au/~/media/NPWS/Images/Parks/Wingham-Brush-Nature-Reserve/park/wingham-brush-01.ashx

Image Credit: http://www.nationalparks.nsw.gov.au/~/media/NPWS/Images/Parks/Wingham-Brush-Nature-Reserve/park/wingham-brush-01.ashx

With Melbourne’s warmer weather fast approaching, a unique little Australian mammal fills the night sky with a quirky array of sound and colour.  The grey headed flying fox is a megabat only found along the East coast of Australia.  Sporting a distinctive grey head and orange-brown collar the grey headed flying fox is a keystone species to our forests and is our only long distance pollinator, flying up to 50km in one night, and maintaining the biodiversity and health of forest ecosystems.  Victoria’s largest colony of grey headed flying foxes is located at the Yarra Bend reserve in Kew where up to 30,000 bats roost in trees along the Yarra River.   Unfortunately despite having large, seemingly stable populations, Melbourne’s grey headed flying foxes are faced by a couple of major threats.  With rising temperatures and increasing urban growth, this species which once numbered in their millions are facing massive population declines with as few as 400,000 grey headed flying foxes remaining in the wild.

Humans and flying foxes share a similar preference for where to establish their homes.  Because of this, increasing human populations and expanding urban sprawl have impeded greatly on the habitat of grey headed flying foxes, pushing their colonies to relocate each time their homes are destroyed.  Prior to the 1980s we had very few flying foxes in Melbourne because the winter climate was too cold for the bats to remain year round, but by 1986 warmer temperatures and a significant increase in the number of feed trees available to these pollen and nectar loving creatures allowed the first colony of flying foxes to establish in the heart of Melbourne.  By 2003 the population of grey headed flying foxes in Melbourne had quickly grown from only 15 bats to over 30,000 individuals.

Photo: Sarah Beebe

Photo: Sarah Beebe

Unfortunately with bats living so close to us and in such large numbers, there’s often a lot of conflict between humans and bats.  Flying foxes are frugivores and as such they feed on the fruits of many trees grown by landowners and farmers.  For this reason many people hold a negative perception of flying foxes without understanding just how important these creatures are in maintaining the health and biodiversity of our gum forests.  Most times humans and urbanisation pose one of the biggest threats to our flying foxes with shooting still legal in certain areas, powerlines causing electrocution, and entanglement from fruit tree netting being just a few of the dangers our bats are faced with.

The other key threatening process that our bats face is global warming.  With temperatures rising at an unprecedented rate each year, our flying foxes are acting as the ‘canaries in the coalmine’ of the climate crisis.  Unlike humans, flying foxes lack the ability to sweat, and with temperatures rising so rapidly they haven’t had time to adapt.  For the grey headed flying fox temperatures over 42 degrees are considered days of extreme heat where these creatures suffer from severe heat stress and are often seen dropping from the trees out of exhaustion.  Global warming is one of the biggest drivers of population declines of our already vulnerable flying fox colonies.

Maintaining flying fox colonies is extremely important, as without these animals we would be without the financial or physical means to do the sheer volume of work that these bats perform every night, at no cost, to conserve our forest ecosystems.  Luckily for these creatures there are many organisations dedicated to ensuring their survival such as the Australian Bat Society and the Australian Research Centre for Urban Ecology who perform monthly bat counts to monitor the success of Melbourne’s Yarra Bend population.  The next megabat count is on the 8th of October, and the group are always looking for volunteers to help out.  To get involved you can contact the counts organiser Rod on 0412 562 429.

Image Credit:  Alison Kuiter, Animalia wildlife shelter.

Image Credit: Alison Kuiter, Animalia wildlife shelter.

 Author: Sarah Beebe. 


Nodding Greenhood (Pterostylis nutans)

Pterostylis-nutans-Nodding-Greenhood-Cows-Horns-Parrots-Beak-Orchid-111.jpg

It’s September and the  weather is finally warming up! Many plant and animal species come out of their winter dormancy at this time of year. Road traffic will soon be held up by hoards of ducklings, possum joeys will start falling out of trees, and everyone will need to dust off the old anti-magpie helmet. However, one species will go about its springtime business largely unnoticed. Nodding Greenhoods (Pterostylis nutans) are flowering right now, all over Victoria.

Nodding Greenhoods, also known as Parrot’s Beak Orchids, are a relatively small orchid that grows up to 30cm high, with flowers up to 25mm long. Each plant bears a single flower, which are easy to overlook as they are green and translucent. Their name refers to the way the flower droops over, causing it to look like a hooded figure (or a parrot’s beak). At the base of the flower stem is a rosette of three to six oval leaves.

Nodding Greenhoods are found throughout most of Victoria, excluding only the dry north-western corner of the state. In regards to Melbourne, this species once inhabited much of the eastern and southern parts of the city, and today can be found in numerous parks and reserves. Nodding Greenhoods can be found throughout the Dandenong Ranges, south to Frankston and surrounds, and as far west as the CBD. Most recently I found them at Baluk Willam Nature Conservation Reserve - an absolute must-see for anyone who is interested in Australian orchids. This reserve is home to 73 orchid species - that’s over one third of Victoria’s orchids all in the one spot! Nodding Greenhoods are locally common, forming large colonies on moist, sheltered sites in a wide range of woodland and open forest habitats.

Nodding Greenhoods are able to reproduce both sexually and asexually. This means that they produce seeds, but also form clonal colonies. This species has a long flowering season, some plants flowering as early as May, others as late as December. The flowers of Nodding Greenhoods are not at all spectacular or eye-catching. Instead, this species attracts its pollinators (namely male fungus gnats) by exuding a scent that mimics the pheromones released by their pollinators’ female counterparts. The male fungus gnat lands on the touch-sensitive labellum (a modified petal), which catapults and temporarily traps the gnat against the column (an organ that both distributes and collects pollen). As the gnat struggles free, it picks up and deposits some pollen, escapes the flower, and then moves on to the next orchid. This is sexual deception as its best - Greenhoods do not produce nectar, so the gnat does all the work of pollinating the Nodding Greenhoods, but alas receives no reward.

As this species exists in relatively dry, nutrient-poor habitats, it has evolved a few mechanisms to help it survive. All Greenhoods are deciduous, meaning that for much of the year they exist as tubers in the soil, avoiding the hot and dry periods that occur over much of Summer and Autumn. Another mechanism that assists in water conservation is the rosette of leaves at the base of the flower, which helps to funnel rain towards the centre of the plant. The water then falls between the leaves at the centre of the rosette to the ground, and is absorbed by the plants roots. In order to combat nutrient-deficiency, Nodding Greenhoods have evolved a mycorrhizal relationship with fungi in the soil. This allows the orchid to exchange photosynthesised organic matter with the fungi in return for inorganic nutrients that the fungus is able to extract from the soil.

This hardy little orchid is inconspicuous and quite boring when you first look at it, but it has a pretty interesting lifestyle. If you find yourself out in the forest anytime soon, make sure to look down. There may be a Nodding Greenhood at your feet - but hopefully not under them!

PHOTO: EMMA WALSH

PHOTO: EMMA WALSH

 

Author: Emma Walsh