€¦ · Web view2021. 3. 21. · SYMBIOSIS: THE ART OF LIVING TOGETHER. Theme. This Special Guided Walk was planned to run in conjunction with a performance, “Symbiosis”, by

SYMBIOSIS: THE ART OF LIVING TOGETHER

Theme This Special Guided Walk was planned to run in conjunction with a performance, “Symbiosis”, by the Australian Dance Party during Enlighten 2021. The walk was open to Friends of the Australian National Gardens and to the General Public.

Contents of this folder1. Cover page2. A map of the Route3. Walk Notes4. Images

As with any planned walk, the notes and images far exceed what you will be sharing with our visitors.

Where possible, we have given references for the information and images

Start of the WalkThe walk is designed to start at the Visitor Centre with the Introduction and Stop 1 at the Bog and Fen Display. At the time of writing, due to the Covid-19 pandemic the start of Regular Guided Walks had been changed to the clock at the end of Banks Way. Feeling optimistic, we decided to leave the walk notes beginning at the Visitor Centre, our pre-Covid start

During the Covid-19 pandemic, we leave it up to Guides to decide whether to: 1. Omit Stop 1 completely and begin the walk by the clock with the Introduction and Azolla

now Stop 1.2. Walk up to the VC for Stop 1 3. Omit Stop 1 but talk about Carnivorous Plants as you walk between stops, or at the end of

the walk.

Thanks toMegan Donaldson and the rest of the Visitor Services Team, who provided the impetus for the walk, advertising and assistance.

Alison Plevey of the Australian Dance Party, who shared the ideas behind their performance and walked and talked us through their route.

Volunteer Guides who came on the practice runs contributed constructively with information, ideas, tips and positive encouragement.

The planning team accepts full responsibility for any errors. Please let us know of any you find so that the document can be amended.

Robyn Black, Mary Bush, Christianna Cobbold, Sue Genner, Wayne Hoy and Tricia MortonMarch 2021

SYMBIOSIS: THE ART OF LIVING TOGETHER

STAND BY THE BOG & FEN DISPLAY SO YOU CAN SEGUE EASILY TO STOP 1

INTRODUCTION: Welcome Name: Volunteer Guides, Members of the Friends of the ANBG Practicalities: length, parking, water Friends: Support of Gardens, Guides

SYMBIOSIS: THE ART OF LIVING TOGETHERWhat is Symbiosis? “Organisms interact with each other in a variety of ways. These interactions can be cooperative, antagonistic, defensive, reciprocal, harmful, communal, opportunistic, beneficial, or neutral. Symbioses encapsulate the relationships that different species of organisms have with each other: the good, the bad, and the ugly.”1

Etymology: From Greek sim, with & biosis, living

Types of Symbiosis:Some debate about what a symbiotic relationship should include.Basic Types2:

Mutualism: both species benefit Commensalism: one species benefits while the other is not affected Parasitism: one species (the parasite) benefits while the other (the host) is harmed

Sometimes the following are included: Predation: one species hunts and kills another species Competition: species compete for the same limited resource.

1 http://untamedscience.com/biology/ecology/basics-of-symbiosis/2 http://untamedscience.com/biology/ecology/basics-of-symbiosis/

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STOP 1: CARNIVOROUS PLANTS - PREDATION

NB: There is not an example of carnivorous plants at this stop but the bog and fen display represents the HABITAT where you might find some carnivorous plants.

CARNIVOROUS PLANTS1 Derive some or most of their nutrients from trapping and consuming animals or protozoans

(single-celled organisms) Can still photosynthesize Approximately 700 species Habitat: thin and/or poor soils, i.e., lacking in nutrients, particularly nitrogen, such as

acidic bogs. Charles Darwin wrote the first well-known treatise of carnivorous plants, “Insectivorous

Plants”, in 1875. Distribution: On all continents except Antarctica, and also many Pacific islands Types of trapping mechanisms:

o Pitfall traps attract prey through nectar &/or bright flower-like patterning. The lining of the tube covered with waxy flakes – slippery for insects & they fall to a pool of digestive enzymes or bacteria e.g. pitcher plants

o Flypaper traps use a sticky mucilage or glue e.g. Droserao Snap traps use rapid leaf movements to trap creature e.g. Venus Fly Trapo Bladder traps have a bladder that generates an internal vacuum and the creature is

sucked into the bladder where it is digested, e.g. bladderwortso Lobster-pot trap is a chamber that is easy to enter but the exit is tricky to find or

obstructed by inward pointing bristles, e.g. Genlisea or corkscrew plants.

DROSERA OR SUNDEWS2

Botanic Name: o from Greek, drosos, meaning dew or dewdrops

Common Name:o From Latin ros solis “dew of the sun”o Refers to drops of mucilage at the tip of the glandular trichomes that resemble

drops of morning dew. Distribution:

o At least 194 specieso On every continent except Antarcticao Australia has approx. 50% of known specieso Prefer bog habitats & soils that lack nutrition.

1 Wikipedia2 Wikipedia

PREDATION: One species kills and consumes another.

Common examples are a large organism consuming a smaller one e.g. owls hunting small mammals. But can also involve small individuals consuming a larger one e.g. piranha fish

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Groups:o Temperate: All North American & European species belong to this groupo Sub-tropical: vegetative growth year round under uniform or nearly uniform

climatic conditionso Pygmy: approx. 40 Australian species with miniature growth, dense formation of

hairs in the crown centre & formation of gemmae (single cell or bunch of cells or modified bud of tissue for asexual reproduction)

o Tuberous sundews: approx. 50 Australian species which have an underground tuber to survive extremely dry summers

o Petiolaris complex: Group of 14 tropical Australian species, which experience constantly warm but sometimes wet conditions.

Description:o Perennial herbaceous plants varying in size and formo Prostrate or upright rosettes 1-100 cm high. Climbing species can reach much

longer lengthso Can live up to 50 yearso Roots weakly developed because nutrient uptake is through carnivorous behaviouro Tentacles: long tentacles protrude from leaves, each with a sticky gland at the tip.

Glands produce nectar to attract prey, a strong adhesive to trap the prey & enzymes to digest it.

IMAGES

1. https://www.nwf.org/Educational-Resources/Wildlife-Guide/Plants-and-Fungi/Sundews2. http://www.sci-news.com/genetics/science-carnivorous-bladderworts-02528.html3. https://physicsworld.com/a/slippery-surface-inspired-by-pitcher-plant/4. https://www.newscientist.com/article/2074582-venus-flytrap-can-count-preys-steps-to-

dissolve-them-alive/5. https://carnivorousplantnursery.com/blogs/carnivorous-plant-information/Genlisea

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WALK ALONG BANKS WAY TO THE POND BY THE CLOCK

STOP 2: ALGAE & CYANOBACTERIA - MUTUALISM

AZOLLA Botanic name: 1

o Named by French naturalist Jean-Baptiste Lamarck in 1783 from specimens collected by Philbert Commerson and his assistant Jeanne Bare from the Magellan region of South America during Louis-Antoine de Bougainville’s 1766-1769 expedition around the world

o From Gk azo meaning to dry and allyo to kill. Refers to the fact that the fern is killed by drought

o In 2010 it was suggested by Carrapico that the name was adopted from the word used by the local population in Argentina or Chile where Commerson collected his specimen.

Azolla is an Australian native fern that is common in many waterways and is commonly used as a decorative feature in garden ponds.

It supports a nitrogen-fixing cyanobacterium in its fronds. This nitrogen is released when the plants decay.

Symbiotic Relationshipo The plant photosynthesizes to produce carbohydrates which it shares with the

cyanobacteria. o The cyanobacteria share the nitrogen they produce with the fern. o This is therefore a resource-resource mutualism.

Description: o Azolla is a free-floating fern, 1–2.5 cm in diameter. o The leaves are tiny, scale-like and 2-lobed (lobes 0.2 cm long). Older leaves can be red

in sunlight and green in the shade. o The main stem has pinnate branches, and branches are longer towards the base of

the stem giving the plant a triangular shape. Distribution:

o Azolla is found in slow moving and stationary waterways, and at least one species is found in each state and territory.

o It can quickly spread to cover open areas of water and may build up in stationary water bodies, particularly if nutrient levels are adequate.

1 www.theazollafoundation.org/Azolla/the-west-discovers-azolla/

MUTUALISM: A relationship between two organisms, which is beneficial to both – a win-win situation

Both organisms benefit from the interaction often resulting in a significant fitness gain for either one or both parties.

Can take the form of resource-resource relationships, service-resource relationships, or service-service relationships

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o Classified as a waterweed in parts of Australia, Azolla produces spores like all ferns and can spread by fragments, so it is exceedingly difficult to remove by mechanical means. Leave one fragment behind and you will quickly have a water body (lake, stream, pond) covered again.

Uses: o Often grown in paddy fields in Asia as a fertilizer.o Great to add to your compost at home as it adds nitrogen and there is always a ready

supply as it spreads so rapidly on home ponds.o Can have it in ponds with fish as it provides a hiding place and, if you have frogs

instead, the tadpoles hide out under it as well. Also means you don’t get any algae growing in your pond.

Types of Azollao Azolla filiculoides does not have fine rootlets. o Azolla pinnata does have fine rootlets.o Similar looking species include: salvinia (Salvinia molesta) in its primary growth stage

and duckweed (Lemna spp. and Spirodela spp.) but these do not have an association with nitrogen-fixing cyanobacteria.

IMAGES:1. Azolla2. Garden pond with Azolla covering surface of pond

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WALK OVER CAFÉ BRIDGE, IN FRONT OF CAFÉ, ELLIS ROWN BUILDING TO THE PIPE WITH THE QUANDONG

STOP 3: PARASITISM USING QUANDONG & EXOCARPUS CUPRESSIFORMIS AS EXAMPLES

QUANDONG SANTALUM ACUMINATUM Botanic Name:1

o Santalum – Latin form of the Gk word santalon, which means Sandalwoodo acuminatum – refers to the acutely shaped leaf tips that are characteristic of this

species Other common names: Desert or sweet quandong, or Native peach. Belongs to the Santalaceae family along with the Sandalwood (Santalum album) and Native

cherries (Exocarpus spp.).1 www.anbg.gov.au/gnp/interns-2002/santalum-acuminatum.html

PARASITE: A plant that derives some or all of its nutrients from another living plant (the host) without contributing to the benefit of the host, and in some cases, causing extreme damage to the host.

The defining structure of a parasitic plant is the haustorium, a specialised organ that penetrates the host and forms a vascular union between the plants

Differs from other plants such as vines, epiphytes and aerophytes, which though supported by other plants, use the other plants simply as a structure on which to grow rather than as a direct source of water and nutrients.

Parasitic plants differ in the extent to which they depend on their host for nutrients:Hemiparasites

o Have at least some ability to photosynthesizeo Primarily rely on hosts for water and mineral nutrients, e.g. Mistletoeo Some species (Obligate parasites) rely on their host for reproduction, whereas

others (facultative parasites) can live and reproduce in the absence of a host.Holoparasites

o Are non-photosynthetico Depend on their host for nutrients.

Parasites manifest in different ways: Some parasitize the roots of the host, e.g. Rape broom, whereas others parasitize the stems.

All parasitic plant species are angiosperms. o Approx. 4,500 species of parasitic plants in 20 families

All evolved from non-parasitic plants (& therefore underwent evolutionary transition from autotrophy to heterotrophy).

Display a wide range of morphologies (forms)o Most grow externally - with the haustorium embedded in the host, but some

grow internally and only emerge to flower. o The haustorium (connecting tissue) may develop from roots or stems.

Britannica.com: Professor James Westwood, Dept. Plant Pathology, Physiology and Weed Science, Virginia Tech US

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o Not to be confused with the tall rainforest trees of the same common name found in subtropical rainforests in NE Queensland, parts of the Northern Territory and northern NSW to Nambucca.

Blue Quandong, Elaeocarpus grandis: Also called Blue Marble Tree or Blue Fig Can grow to be a huge tree, typically 40 metres tall, with well-developed

buttress roots. It has marble sized blue fruits and a distinctive seed that looks like a brain.

Parasitic Nature:o The quandong is a hemiparasitic plant. This means that the plant is partially

parasitic and relies on host plants for water and mineral nutrients (from the soil) but not for sugars – which is why such parasites have green leaves, i.e. they have the ability to photosynthesize and produce their own supply of carbohydrates.

o It has a modified root structure called a haustorium, which attaches to the roots of other trees for nutrients and water supply.

o The Quandong normally has more than one host. It commonly attaches to nitrogen-fixing trees such as Acacias (wattles) and Casuarinas (she oaks), but also parasitises other legumes, shrubs (e.g., saltbush and bluebush) and grasses.

Habitat:o Endemic to Australia, the quandong is widely dispersed throughout most southern

regions of Australia including the arid area of the central deserts. It is found north to Karratha in WA and east to Dubbo in NSW.

o It is found in a wide variety of habitats characterised by nutrient poor, free draining soils, e.g. semi-arid sandy habitats.

o Tolerates drought and salinity. It favours full sun. Description:

o Small desert tree that grows from one to 6 metres in height, with rough bark o Pale green to olive leaves that are classically eucalyptus shaped – elongated and

often with a sickle-like curve. Fruit:

o The bright red 2-2.5 cm long fruit contains one large nut, which is sometimes only marginally smaller than the fruit.

o Game of Bully1: Game common among boys. A hole was drilled through a quandong nut so that a piece of string could be threaded through it and then knotted at one end. A 50cm to 75cm circle was drawn on the ground, a boy put his ‘bully’ in the middle, holding the string, and the other boy whacked it with his ‘bully’, trying to smash it. They take it in turns if they miss. Spare bullies are stored on another string. Newer bullies more prized as older ones too brittle. Elaborate number system!

o It is prized by Aboriginal Australians as highly nutritious bush tucker and contains approximately twice the vitamin C of an orange. It is described as slightly sour and salty with its sweetness varying considerably between trees. Its aroma is likened to “dry lentils or beans with earthy fermented notes”. 2

o It is increasingly used commercially across Australia in condiments e.g. quandong jam.

1 www.macquariedictionary.com.au & personal recollection by Wayne Hoy, ANBG Volunteer Guide2 Hospitality Magazine, August 2018

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CHERRY BALLART, EXOCARPOS CUPRESSIFORMIS – A LOCAL EXAMPLE OF A PARASITE Botanic name:

o Exocarpos – From Gk exo, outside and carpos, a fruit, meaning ‘outside fruit’ - refers to the fleshy false ‘fruit’

o cupressiformis meaning cypress like – refers to the similarity to the conifer Cupressus

Other common names: native cherry, cypress cherry Belongs to the Sandalwood family of plants. Parasitic Nature:

o In early stages of development especially, they are hemiparasitic on the roots of other trees, particularly Eucalyptus.

o Mature trees are less parasitic – less reliant as photosynthesis is established in their stems.

o Common locally, e.g. Mt Majura, Black Mountain. Also in ANBG, e.g. Sydney Gully Habitat:

o Endemic to Australia, common to southeast Australia from Mackay to Adelaide and Tasmania, with a few outlier populations near Cairns.

o Often grows in sclerophyll forests in shallow soils (hence the parasitic use of roots of the host).

Description:o Shrub or small tree 3-8 m that resembles a cypress – often pyramidal in shape. o The drooping stems are the site of the photosynthesis.o Inconspicuous flowers are arranged in clusters on short spikes 3-6 mm long but only

one flower on each spike forms a fruit. o Flowers throughout the year but mainly October – May.

Fruit:o The inedible fruit forms as a globular hard greenish nut containing one seed, on top

of a short stalk, the pedicel. o As the fruit develops the stalk swells to 5-6 mm in diameter and turns yellow or red

to form the edible “cherry”. o Note: the swollen stalk has no hard stone in the middle as in a European cherry.

Hence the original name Exocarpos from the Latin meaning outside fruit. o Bush Tucker: Some say to wait until the fruit is dark before eating.

IMAGES:1. Quandong fruit and seed2. Exocarpus cupressiformis tree3. Exocarpus cupressiformis fruit4.

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CONTINUE WALKING TO THE BANKSIA GARDEN & TO THE BANKSIA BLECHNIFOLIA PLANTING BY THE SHELTER

STOP 4: BIRD & MAMMAL POLLINATION - MUTUALISM

Although most plants rely on insects for pollination, in Australia there are many for which birds are the primary pollinators, even though insects are frequent visitors. There are others where non-flying mammals are also important or even the primary pollinator.

Birds pollinate 1000 Australian plant species. At equivalent latitudes in N America the number is 8, in Asia it is 2, in all of Europe and N. Africa the figure is zero1.

Banksia inflorescence & flowers The flowering spikes have many hundreds of individual flowers, which usually open from

the bottom up. Individual flowers resemble Grevillea flowers with the style and stigma initially acting as a

pollen presenter.

Bird-pollinated banksia: Often brightly coloured Not usually perfumed as birds have no sense of smell Produce abundant nectar and The pollen presenter is remote from the nectar. Flowers are closely grouped and often high up on the plant and conspicuous.

Pollination: When the bird visits the flower in search of nectar from the base of the flower, pollen is dusted onto its forehead, throat and beak. After the pollen has been transferred the flower becomes receptive to accept pollen from the head of another visiting bird.

Mammal-pollinated banksia: Produce copious nectar, Many have a strong perfume, The flower head may be close to the ground and often concealed in the foliage Some are dull or brown coloured. Perfumed banksias:

o Can have a spicy or sweet scent. For example, B. solandri has been described as having a ‘sweet and musky’ odour, smelling of ‘coconut, cherry and musk’.

o Others smell less sweet: Alex George is reported as describing B. nutans as having a ‘pungent onion smell’ and saying that several species smell like rodents.

o It is thought that the odour helps the non-flying animals find the flowers at night, which is when they are most active, and some banksias also produce more nectar at night to attract them.

Mammals known to visit and probably pollinate banksias include honey possums, pygmy possums, dunnarts, antechinus and bush rats.

1 Ian Fraser Four Seasons of the Bush Capital CD


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Banksia blechnifolia Botanic name: Banksia after Joseph Banks, and blechnifolia for Blechnum (a fern) and

folium (leaf) for its resemblance to the Blechnum fern. Found in SW WA around Esperance on sandy soil no closer than 10kms from coast No studies have been conducted on B. blechnifolia but its characteristics are similar to

other banksias from SW WA, which are pollinated by non-flying animals.

IMAGES:1. Banksia ericifolia with Red Wattlebird showing opening from the top, bright colour and

held high up in the plant 2. Banksia blechnifolia showing dull colour, opening from the bottom and easily accessible to

non-flying marsupials and rodents. 3. Honey Possum or Noolbenger

RETURN TO MAIN PATH, WALK TO JUST BEFORE MARKER #17 ON THE MAIN PATH ON LHS. HERE A LEPTOSPERMUM TREE HAS LICHEN ON ITS BARK

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STOP 5: LICHENS: A RESULT OF A SYMBIOSIS BETWEEN DIFFERENT ORGANISMS - MUTUALISM

LICHENS1

Botanic Name: o From Greek, leichen, meaning “licker” to lick

Distribution:o 20,000 known species worldwide, 3000 from Australiao Occur from sea level to high alpine elevationso Many different environments: artic tundra, deserts, rocky coasts, toxic slag heapso Generally terrestrial but a few aquatic lichens knowno Grow on almost any surface: from natural (bark, leaves, mosses, rocks, soil, bone,)

to man-made (walls, gravestones, rubber, slagheaps, bitumen, concrete, glass, metal). Can even grow inside solid rock between the grains.

o 6-8% Earth’s land surface covered by lichens Uses

o Food: not as a major food source o Medicine: o Dyeing of textiles, e.g. Harris Tweedo Still used today in manufacture of perfumeso Pollution monitor:

Growth Formso Display a variety of forms. 3 common types are fruticose, crustose & foliose

Fructose: erect or pendulous and markedly 3-dimensional Crustose: markedly 2-dimensional and firmly attached to substrate by their

entire lower surfaces. Impossible to see their undersurface. Looks like a thin crust on the substrate.

Foliose: halfway between fruticose & crustose. Obviously 3-dimensional, they grow in more-or-less sheet form, but often with a lobed appearance. Not attached by entire lower surfaces so it is possible to see lower and upper surfaces.

SYMBIOTIC RELATIONSHIP Lichen is NOT a single organism but a composite organism that is a symbiosis between

different organisms – a fungus & an alga or cyanobacterium. Latter often called ‘ blue-green algae’ but are not algae.

Non-fungal partner contains chlorophyll and is called a photobiont Fungal partner may be called a mycobiont Most partnerships are with 1 photobiont & 1 mycobiont. But there are lichens with more

than one photobiont partner.

1 anbg.gov.au/lichen


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Fungi cannot photosynthesize. Every fungus needs existing organic matter from which to obtain carbon, which they get from the alga/cyanobacteria. Alga and cyanobacteria contain chlorophyll and therefore can photosynthesize producing carbohydrates

The alga/cyanobacteria benefits through protection from the environment by the filaments of the fungi, which also gather moisture & nutrients from the environment. The fungi also provide an anchor to it.

The lichen symbiotic relationship extends the ecological range of both partners.

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WALK UP THE MAIN PATH, CUT THROUGH TO ROAD BY BOTTLE TREE. AS WALK ALONG TALK ABOUT…

ANIMALS LIVING AMONST PLANTS & BIRDS NESTING IN TREE HOLLOWS: COMMENSALISM

ANIMALS LIVING AMONGST PLANTS: Xanthorrhoea species, which form a skirt from old leaves, can provide safety and shelter

for small birds and mammals. Other prickly shrubs provide safety and shelter

o Certain WA banksias – B. repens & B. blechnifoliao Triodia sp e.g. T. scariosa or Spinifex/Porcupine Grass, has sharply pointed leaves

that end up rolled and stiff, making tussocks impossible to enter for most larger animals.

o The Striated and Carpentarian grasswrens spend most of their time in & around Triodia tussocks, feeding on insects & seeds. When predators appear, they dart inside the tussocks for protection.

o RCG has examples of Triodia

IMAGES 1. Carpentaria Grasswren

BIRDS NESTING IN TREE HOLLOWS1

Tree hollows take many years to develop:o 100 years for small hollows suitable for small mammals e.g. Brush-tailed phascogale

& eastern pygmy possum o 200 years for medium sized suitable for parrotso Even longer for larger & deeper hollows suitable for larger parrots e.g. glossy black-

tailed cockatoos & animals, e.g. masked owl Entrance size & shape, depth & degree of insulation influence which species use which

hollows & the frequency of use 17% bird species, 42% mammals, 28% reptiles (% are for Australian species) need tree

hollows Range of hollow types needed for biodiversity Eucalypts appear to be the preferred tree but there does not appear to be a species-

specific relationship between tree & animal. Maybe eucalypts live long enough to form the most tree hollows?

1 https://www.wires.org.au/wildlife-info/wildlife-education/tree-hollows-for-wildlife

Commensalism: A relationship between two organisms, in which one species obtains food or other benefits from the other without either harming or benefiting the latter. Win-neutral

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WALK UP ROAD TO ROCK GARDEN WATERFALL & STOP AT THE EREMOPHILAS…STOP 6: FLOWER SHAPES & POLLINATION USING EREMOPHILAS AS AN EXAMPLE – MUTUALISM

NB: Check this stop before the walk to see if there are any flowers on the plants. There is another insect-pollinating eremophila on the route opposite the Eucalyptus macrocarpa

EREMOPHILAS

Botanic name: o Named by Robert Brown in 1810 (botanist with Flinders, librarian to Bankso eremos: meaning desert and phileo meaning lover.

Common Names: Poverty Bush: refers to poor soils it grows ino Emu Bush: emus eat large amounts of fruit and seeds. Seeds then distributed in

droppings along with some fertilizer.o Fuchsia Bush, Tar or Turpentine Bush

Distribution: semiarid and arid regions. All mainland states and NT but majority in WA especially around Kalgoorlie

Pollination: 2 groupings: 75% insect attracting and 25% bird attracting.o Insect: white, blue, violet with lower lips projecting forward to provide a landing

place for insects; shorter floral tubes & shorter stamenso Bird: red, orange, yellow or green with lower lobes that point downwards to

discourage insects; longer stamens that brush nectar onto a bird’s head; longer floral tubes

Uses: Indigenous peoples used plant material in ceremonial rites, extracts and decoctions used as liniments, medicines and antiseptics

REPLENISHING NECTAR1

Providing nectar uses energy but the plant benefits because transfer of pollen is more likely Time to replenish nectar varies from 20 minutes for some plants to a day Depends on

o Plant health – large, healthy plants produce more flowers and each flower is likely to have more nectar

o Microclimate – in hot dry conditions nectar evaporateso Flower age

For many species nectar production is fairly constant until the flower reaches a certain age

IMAGES1. Parts of a Flower

WALK UP THROUGH RHS OF ROCK GARDEN TO THE ACACIA SECTION…

1 www.askascientist


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STOP 7: NITROGEN-FIXING BACTERIA & ACACIAS – MUTUALISM2

ACACIAS Acacias are legumes, as are the peas and beans that we eat, sweet peas, clovers, other

herbaceous plants such as Sturt's Desert Pea and many shrubs and trees with pea flowers. Acacias used to be in a separate family, Mimosaceae, but this has now become a subfamily,

Mimosoideae, within Fabaceae (formerly called Leguminoseae). Their flowers are quite different from pea flowers but the fruit are pods like those of other

legumes. Root nodules:

o Like other legumes, most acacias can form symbiotic associations with nitrogen (N2)- fixing bacteria.

o Infection of acacia roots by nodule forming bacteria often occurs through root hairs, but it can also occur through wounds or breaks in the root system2 (NFinA p.36).

o The bacteria multiply and gradually nodules start to form.

NITROGEN-FIXING BACTERIA Belong to Rhizobiaceae family & referred to as rhizobia Able to utilize inert atmospheric nitrogen to produce ammonia (NH3) At least 6 genera form associations with acacias, inc. Rhizobium & Bradyrhizobium. Some acacias are limited to a very few species of bacteria while others have many.

SYMBIOTIC RELATIONSHIP Ammonia produced by the rhizobia is absorbed by the plant and used to manufacture

amino acids and proteins. The plant, through its roots, supplies the energy required by the rhizobia. If the soil is fertile, acacias can grow quite well without the N2-fixing bacteria. However,

the association with N2-fixing bacteria means that acacias can compete ecologically & grow in poor soils.

Similarly, the rhizobia can survive long periods in the soil without a nodule-forming plant to associate with, but flourish when in a symbiotic relationship.

SAHEL REGION AFRICA Plantations of acacias are helping to halt desertification Grown as a pioneer species, improving the soil so that other plants can be grown. Then

insects & other animals return. Acacias provide wood for fuel & other uses, leaves & seeds for fodder for livestock.

2 A simple botany of wattles, Calder Chaffey, Australian plants online, at http://anpsa.org.au/APOL8/dec97-1.htmlNitrogen fixation by legumes: https://aces.nmsu.edu/pubs/_a/A129/#:~:text=In%20legumes a%20bacterium%20and%20a%20plant. Nitrogen fixation in Acacias: https://aciar.gov.au/sites/default/files/legacy/node/619/mn115part1.pdfThe Acacia Tree Project, at http://acaciatreeproject.com.au/acacia-tree-project/Information on Acacia colei provided by John Turnbull, ANBG Volunteer Guide, in 20132 Nitrogen fixation in Acacias: P.36 https://aciar.gov.au/sites/default/files/legacy/node/619/mn115part1.pdf


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http://acaciatreeproject.com.au/acacia-tree-project/

Importantly, in an area subject to drought & famine, the seeds of some acacias can be processed and used in traditional cooking.

Acacia colei was selected for its bountiful production of nutritious seeds which are high in protein (21%), can be processed easily and store well.

Some years ago, Aboriginal women from central Australia visited Niger and taught the local people how to prepare food from the seeds.

Acacia flour has subsequently become a part of many local dishes.

IMAGES1. Legume plant root showing nodules attached to roots2. Nitrogen-fixing nodules of Acacia saligna3. Root nodules on an Acacia sp4. Farmers with acacia crops in Niger

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WALK ALONG ROAD TOWARDS RAINFOREST. AT TOP OF STEPS LEADING DOWN TO ROCK GARDEN…

STOP 8: ANOTHER EXAMPLE OF FLOWER SHAPE & POLLINATION, USING GREVILLEA “MASON’S HYBRID” 1- MUTUALISM

Grevilleas Botanic name: Genus Grevillea is named after Charles Francis Greville who was one of the

founders of the Royal Horticultural society in 1804 In Proteaceae family along with Banksia, Hakea, Isopogon, Telopea and Dryandra etc. 300 species in the genus, most endemic to Australia but some in PNG & islands to the

north In flower most of the year but winter –early spring peak time Most Proteaceae species are designed for fertilization by birds and grevillea flowers are

especially well designed for this. Some species rely on other methods of pollination, e.g. beetles, moths, bees, ants and even small mammals.

Grevillea Morphology & Pollination: Small flowers occur in clusters or inflorescence. Common forms of inflorescence are described as ‘spider’ and ‘toothbrush’. Flowers are often red-orange which is the end of the spectrum that birds see best. In the bud:

o Each flower is an elongated narrow tube (perianth)o The anthers are appressed (very close) to the insides of the four segments

(petals/sepals or tepals) of the flower tube or perianth, instead of the usual arrangement in flowers of the male stamen, which has the anthers atop a filament, free from the flower tube.

o The female stigma and style lie within the closed perianth, the stigma held near the tip alongside the four anthers.

Development: o During development, the style elongates and protrudes, hook-like, through a break

between perianth segments.o The (male) anthers mature, releasing pollen before the stigma matures and

becomes receptive. This condition, called protandry,is one method of ensuring cross-pollination rather than self-fertilization.

o When the pollen grains are released from the anthers they adhere to the immature stigma. This is then released from the perianth and becomes the ‘pollen presenter’ held some way from the perianth, now open. It is ‘presenting’ the pollen to the pollinator.

o A honeyeater, accessing the nectar, brushes its head against the pollen presenter and flies away with pollen on its head to another flower that may already have a receptive stigma.

1 ANPSA Plant Guide: Grevillea


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o After all the pollen is removed, the style becomes receptive so that pollination can occur with pollen from another flower. A bird, already with pollen on its head, transfers pollen by brushing against the now receptive style as it drinks the nectar.

Images1. Photo of Grevillea ”Mason’s Hybrid” 2. Photo of a Grevillea inflorescence & diagram of a flower3. Diagram of New Holland Honeyeater drinking nectar from a flower4. Botanical illustration of Grevillea asplenifolia

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WALK DOWN STEPS, TURN RIGHT INTO GYMNOSPERM SECTION, PASSING ON LHS…

STOP 9: BIOCHEMICAL INTERFERENCE OR ALLELOPATHY USING CASUARINA AS AN EXAMPLE - COMPETITION

WHAT IS ALLELOPATHY?1

Allelopathy: from Greek allelo and pathy meaning “mutual harm” or “suffering” A biological phenomenon where one plant inhibits the growth of another through the

release of biochemicals, called allelochemicals. Can be beneficial (positive allelopathy) or detrimental (negative allelopathy) Term first used in 1937 Characteristic of certain plants, algae, bacteria, coral and fungi Important factor in species distribution & abundance within plant communities and, also,

the success of many invasive plants

BACKGROUND2

Research in late 60s-early 70s in mostly chaparral in NW USA Communities dominated by small leaved evergreen shrubs Well adapted to recovering from grassland fires Cyclical pattern - biodiversity increases after fire, but decreases as time since last fire

increases Frequent fires can result in almost pure stands of just one or a few species Community type common across world, including SE Australia

Findings Dominant plants produce chemicals Gases released from leaves inhibit growth of nearby susceptible plants Stored in leaves, bark etc., become part of litter Washed into soil by rain, inhibit germination - both their own and other seeds Destroyed by fire – allowing germination again Gradual re-accumulation after fire starts the cycle again Some plants can also release chemicals directly into soil from their roots.

1 Wikipedia2 Robyn Black, ANBG Volunteer Guide, pers.comm.

COMPETITION: A relationship between two or more organisms, populations or species that share an environmental resource when this is in short supply. It results in either replacement of one species by another or in the modification of species by selective adaptation.

Typical resources within the plant world include light, water, specific nutrients, space, and pollinators

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Typical indicators of allelopathy at work a) Little or no undergrowth - “Where Gidgee grows little else grows”1

b) Stand of single age trees.

Casuarina: Note dense litter and lack /scarcity of understory plants. Compare this with what we’ve seen so far on this walk, and keep in mind for when we are

in the rainforest. Can you think of any other trees that might display allelopathy? Examples include:

o Pines o Black Walnuto Eucalyptso Rhododendron

HUMAN IMPACT & ALLELOPATHY 2

Positive stories 2005: Callisto - a registered herbicide from Callistemon citrinus was released as a broad-

spectrum maize-weed herbicide. 2005 Acacia cambagei being investigated for control of annual ryegrass 2019 Findings that some cereals are doing their own weed control – with just a little help

from humans! At least three cereal species release weed inhibiting allelochemicals from their roots – but the natural mycorrhizal fungi and soil bacteria associated with the roots change these chemicals into different, much more effective ones. So, the human lesson/imperative here is that making sure that cropping practices keep a really healthy soil micro biota in place will reduce weeds without any other intervention.

A quirky story – 1986: In the USA wheat area, there is a parasitic weed, Striga, whose germination is actually stimulated by allelochemicals released by their host plants! The very complicated chemical involved is sufficiently similar to ethylene that the control method developed is to inject ethylene gas into the soil during the fallow period to induce “suicidal germination” and reduce the seed bank before the growing season.

Negative stories 2015: South Africa - Western Cape E. camaldulensis

o Purpose – not knowno Effect – inhibition of at least 4 native species, now invasive and changed river

morphology and stream flow, i.e., virtually destroyed riverine habitats 2018 Kenya E.grandis

o Purpose – provide fast growing, coppicing firewood supplies for small farmers to improve life.

o Effect – inhibition of many of the basic crops reduced self-sufficiency, i.e., poor became poorer!

2016 SE China Eucalyptus spp - finding a solution to a problemo Purpose – plantations because of fast growth and versatile useso Effects – a native fern was the only plant, which grew as understory, any other

planting attempts failed.o Research findings

1 2005 Min An & J Pratley2 Robyn Black, ANBG Volunteer Guide, pers.comm.

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Both species released allelochemicals, but the combination was synergistic, i.e., they mutually increased each other’s effects

Removing the fern improved the chances of other angiosperms growing Choosing tree and shrub species less susceptible to the eucalypt

allelochemicals made planting multi species mixed forests possible giving better ecosystem services and greater productivity.

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CONTINUE INTO GYMNOSPERM SECTION…STOP BY MACROZAMIA COMMUNIS.

STOP 10: POLLINATION BY INSECTS USING MACROZAMIA AS AN EXAMPLE – MUTUALISM

CYCADS Ancient plant – fossil record to Permian, 280ma. Jurassic period common. Changed very

little since then. Gymnosperm (naked seeded) i.e. unfertilized ovules are open to the air to be directly

fertilized by pollinators. (Flowering plants have enclosed ovules) Grow very slowly – some specimens over 1000 years old.

Description: o Cylindrical trunk. Leaves grow directly from trunk, fall when older leaving a crown of

leaves at top. Leaves large in proportion to trunko Wide variety of leaf shapes, cones & seeds. o Similar in appearance to palms & ferns but only distantly related to either

Uses: o Food by some indigenous tribes. Health risk, as seeds have to be ground and soaked

to remove toxins. Eating bush animals that have eaten cycad seeds also risky.o Decoration during festivals & celebrations

Pollination Dioecious – male & female plants Most Australian cycads pollinated by thrips or weevils

Macrozamia communis aka Burrawangs 1

Burrawang – name in Dharuk language Most southerly occurring cycad in the world - found from Taree to Bega Pollination

o On the male plant, the cones are home to generations of weevils. o When a female cycad is ready to be fertilised, it emits a pheromone. o The male cycads in the vicinity detect the smell and an interesting process occurs.

The male cones heat up through a process called thermogenesis. o The temperature increase can be up to 16°C. This makes the male cone very

unpleasant for the weevils. o So they leave, carrying a load of pollen. They also detect the female pheromone

and visit the female cone and the pollen they are carrying fertilises the female ovules.

o Once fertilised, the female plant ceases to emit the pheromone and the nearby male plants begin to reduce the heat in their cones. However, the female plant now increases the temperature of its cones to deter the weevils so that they do not remain to eat the developing seeds. The weevils leave the female plant and return to the males.

1 Plant Evolution Walk by Pam Cooke, ANBG Volunteer Guide, on Guides Web


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IMAGES1. Male cone dehiscing Macrozamia communis2. Female cone receptive Macrozamia communis3. Weevils congregating on a male cone4. Thermal imaging of Macrozamia communis5. Macrozamia communis weevil, Tranes lyterioides

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EXIT GYMNOSPERM SECTION ON PATH LEADING UP TO ROAD, WALK TOWARDS RAINFOREST TO SECTION WITH ARMILLARIA. TURN UP THE ROAD FOR A SHORT DISTANCE & STAND WITH YOUR BACK TO THE RAINFOREST, LOOKING NORTH

STOP 11: FUNGAL DISEASES, e.g. ARMILLARIA – PARASITISM

ARMILLARIA1

Botanic Name: o From Latin, armilla, meaning bracelet – refers to the bracelet-like frill on the fruiting

bodies Common Name:

o Honey mushroom, honey agaric: after colour & mushrooms producedo Mushroom root rot, toadstool disease: refers to the mushrooms produced

1 Wikipedia & https://projects.ncsu.edu/cals/course/pp728/Armillaria/Armillaria.htm

PARASITE: A plant that derives some or all of its nutrients from another living plant (the host) without contributing to the benefit of the host, and in some cases, causing extreme damage to the host.

The defining structure of a parasitic plant is the haustorium, a specialised organ that penetrates the host and forms a vascular union between the plants.

Differs from other plants such as vines, epiphytes and aerophytes, which though supported by other plants, use the other plants simply as a structure on which to grow rather than as a direct source of water and nutrients.

Parasitic plants differ in the extent to which they depend on their host for nutrients:Hemiparasites

o Have at least some ability to photosynthesizeo Primarily rely on hosts for water and mineral nutrients, e.g. Mistletoeo Some species (Obligate parasites) rely on their host for reproduction, whereas

others (facultative parasites) can live and reproduce in the absence of a host.Holoparasites

o Are non-photosynthetico Depend on their host for nutrients.

Parasites manifest in different ways: Some parasitize the roots of the host, e.g. Rape broom, whereas others parasitize the stems.

All parasitic plant species are angiosperms. o Approx. 4,500 species of parasitic plants in 20 families

All evolved from non-parasitic plants. (& therefore underwent evolutionary transition from autotrophy to heterotrophy.)

Display a wide range of morphologies (forms)o Most grow externally - with the haustorium embedded in the host, but some

grow internally and only emerge to flower. o The haustorium (connecting tissue) may develop from roots or stems.

Britannica.com: Professor James Westwood, Dept. Plant Pathology, Physiology and Weed Science, Virginia Tech US

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o Resin glut or resin flow: conifers often respond to infection by producing copious amounts of resin

Distribution: At least 10 species: 5 in Australia

o On every continent except Antarcticao One of the most common fungi in a forest soilo Lives on wide range of angiosperms & gymnosperms

Description:o Long lived & forms some of the largest living organisms in the world e.g. patch in

Oregon’s Malheur National Forest covers more than 8.8 km2 & is more than 2,400 years old

o Destructive forest pathogen: Feeds on dead plant material as well as living & therefore will kill its host

o Some species display bioluminescenceo Occurs naturally and becomes a problem when it has the potential to increase in

size and become the sole fungus in an area.o Spread by root to root contact (cf Phytopthora which spreads through soil like

water)

Armillaria & the ANBG1

Armillaria luteobubalina was probably occurring naturally on the ANBG site before the Gardens’ development. It would have maintained a stable population in Black Mt vegetation without having the ability to increase in size and therefore kill off surrounding vegetation.

The development of the ANBG in the 1960’s provided an increased food source (plants being planted more densely than the natural vegetation) & improved growing conditions (soil, water, maintenance), thus giving the fungus an opportunity to increase in size.

Strategies:o Open fell clearingo Trenching: used here (Look at bitumen and note re-surfaced area running alongside

the bed) Trench dug down to approx. 3-4 m Stiff plastic sheet of root barrier inserted down one side of trench Herbicide applied to the bottom of the trench, back fill with 300mm thick

fill, more herbicide, more back fill, and so on until trench fullo Sanitation:

Collection of fruiting bodies for destruction Separating & burning of infected timber Keeping soil contained Disinfecting tools and machinery

o Monitoringo Testing myceliumo Inoculums: Armillaria is not a competitive fungal pathogen. Believed that some

fungi can ‘out compete’ Armillaria so if inoculate area with another fungus that would keep Armillaria to a size that is not a problem

NB: New plantings of Prostanthera cineolifera or Singleton mint bush, in February 2021. Will be interesting to monitor these plantings.

1 https://www.anbg.gov.au/gardens/about/management/policy-docs/Armillaria-Strategy-2003-2013.pdf

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ENTER RAINFOREST, WALK DOWN TO BRISBANE BRIDGE. AS WALK ALONG TALK ABOUT…

STRUCTURE OF RAINFORESTS – COMPETITION

STRUCTURE OF RAINFOREST Canopy, mid-level, forest floor Reduced sunlight: plants competing for sunlight not water. Characteristics of plants:

o Large, spreading, glossy leaves with central vein to shed watero Dark greeno Densityo Plants growing straight up to sunlight

Vines1:o From Latin vinea grapevine or vineyardo Any plant with a growth habit of trailing or scandent (i.e. climbing) stems, lianas or

runnerso Growth:

Some plants always grow as vines while a few grow as vines only part of the time, e.g. poison ivy can grow as low shrubs if no support but will become vines when support is available

Growth form based on long stems: Advantage of not investing energy in supportive tissue, enabling a

plant to reach sunlight with minimal investment of energy e.g. kudzu and Japanese honeysuckle.

Also enables plants to colonize large areas quickly, e.g. ground ivy, periwinkle. This is because it can root in soils adjacent to exposed areas with more sunlight but little or no soil but its leaves can be in the sunnier areas

Some tropical vines can exhibit skototropism, i.e. can grow away from the light. This means they can reach a tree trunk, which they then climb to reach the sunlight

o Climbing methods Twining around a support, e.g. morning glories, Ipomoea sp Adventitious, clinging roots, e.g. ivy Twining petioles, e.g. Clematis sp Tendrils, which can be specialized shoots, e.g. Vitaceae, leaves, e.g.

Bignoniaceae, or even inflorescences, e.g. Passiflora Tendrils that produce adhesive pads at the ends, e.g. Parthenocissus

1 wikipedia.org/wiki/Vine

COMPETITION: A relationship between two or more organisms, populations or species that share an environmental resource when this is in short supply. It results in either replacement of one species by another or in the modification of species by selective adaptation.

Typical resources within the plant world include light, water, specific nutrients, space, and pollinators

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Prickles, e.g. climbing roses, or other hooked structures

AT BRISBANE BRIDGE

BIRDS SPREADING PLANT SEEDS USING CASSOWARY AS AN EXAMPLE - MUTUALISM

CASSOWARY1

Sixty six million years ago a large asteroid impacted the earth causing a mass extinction of species. A number of groups did survive including the ancestors of the birds.

The same height as a human, 50-60kg, this ground dwelling bird eats fruit, occasionally insects, fungi and small vertebrates and carrion2.

Ratites – large flightless birds - relatives include emu, ostrich, rhea Three species:

o Southern Cassowary: limited in Australia to 3 unconnected populations in northern Queensland, also in New Guinea

o Dwarf Cassowary: smallest cassowary, mountain forests of New Guinea, New Britain & Yapen Island

o Northern Cassowary: northern New Guinea They have dagger-like claws and a lethal kick Only 1500-2000 birds remain in Australia today, putting them on the endangered list. So,

they can survive a catastrophic extinction event, but not the arrival of Europeans and their associated feral companions.

A habitat-specific bird, living only in the ever-shrinking rainforests of northern Queensland. Similar to emus, but don’t take to the wide-open spaces.

Females tend to be large and domineering and take on up to 3 mates per season, leaving the males to hatch the eggs (50 days) and rear the young through to about 12 months.

Survival of the cassowary depends on healthy rainforests, however these are being increasingly cleared for 'development'. Climate change is producing longer dry periods and more severe cyclones, restricting feed availability for the cassowaries. Feral animals, such as pigs, cats, dogs and foxes as well as humans, add to the pressure on the remaining cassowary populations.

Recently authorities have seen the need for wildlife corridors linking the remaining rainforest patches in Northern Queensland. Long live the cassowaries!

SYMBIOTIC RELATIONSHIP Cassowaries eat up to about 5 kg of mainly fruit each day and walk up to about 7km per

day, spreading the seed of many forest species.

1 Documentary ‘About Cassowaries’ by David Attenborough and Brendan Chew2 www.bushheritage.org.au/species/cassowary


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Eat fruit from 238 plant species1

Their digestive tract is short and gentle, so very little damage is done to the seeds as they pass through.

Some rainforest species, e.g. the Cassowary Plum (Cerbera florabunda), produce a large fruit that is toxic to other animals but not to the cassowary. Seeds of this variety that pass through the digestive system of a cassowary are actually much more likely to grow into a plant than those that just fall to the ground.

The plants in the rainforest benefit because cassowaries distribute not only a wider variety of seeds than other animals, but a higher volume.

IMAGE1. Cassowary scat with seeds

EPIPHYTES - Commensalism

WHAT IS AN EPIPHYTE? "An epiphyte is an organism that grows on the surface of a plant and derives its moisture

and nutrients from the air, rain.... or from debris accumulating around it." 2

o Epiphytes gain access to higher light levels than on the forest floor. As well as direct rainfall, rainwater trickling down tree trunks tends to accumulate nutrients.

Worldwide, most epiphytes are flowering plants such as orchids and bromeliads while the second largest group is ferns. There are also mosses, gnetales and cycads (!).

In Australia: 3

o Southeastern Australia: ferns and mosses grow as epiphytes on tree ferns.o Further north in subtropical and tropical rainforests: ferns and orchids

predominate. There are a few dicots as well. Australian Epiphytes: 4

o Ferns: Bird's nest ferns - see example at Brisbane Bridge - and staghorn ferns are two species which gain much nutrient from decomposition of leaf litter and insects collecting in the 'nest'.

Bird's nest fern, Asplenium australasicum, occurs in rainforest and wet sclerophyll forest near the east coast from northeastern Queensland to southeastern NSW, on Norfolk Island and New Caledonia. As an epiphyte or on rocks or banks. 5

1 www.bushheritage.org.au/species/cassowary2 https://en.wikipedia.org/wiki/Epiphyte3 The University of Tasmania Open Access Repository The distribution of epiphytes over environmental and habitat gradients in tropical and subtropical Australia, at https://eprints.utas.edu.au/23443/#:~:text=Epiphytes%2C%20plants%20which%20grow%20on,have%20been%20undertaken%20in%20Australia.4 The Australian Vascular Epiphytes: Flora & Ecology, UNE Doctoral thesis, Wallace, BJ, at https://rune.une.edu.au/web/handle/1959.11/233485 Flora of Australia, Asplenium australasicum https://profiles.ala.org.au/opus/foa/profile/Asplenium%20australasicum

Commensalism: A relationship between two organisms, in which one species obtains food or other benefits from the other without either harming or benefiting the latter. Win-neutral

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https://eprints.utas.edu.au/23443/#:~:text=Epiphytes%2C%20plants

Staghorn fern, Platycerium superbum, occurs in lowland rainforest in Queensland and northern NSW. A large nest frond attaches to and wraps around the trunk of the host tree and holds the rhizome and short roots. The antler-shaped fronds produce the spores.1

o Orchids:2

Less than 20% of Australia’s 1700 species of orchids are epiphytic Although two species are found in Tasmania, nearly all the epiphytes occur

in the tropics

ANBG RAINFOREST GULLY Lots of bird's nest ferns, other ferns and various orchids. Tree a few meters from entrance: A staghorn, a bird's nest fern and another small-fronded

fern plus an orchid.

IMAGES:1. Plant in cultivation on an Angophora , Rainforest Gully2. Ficus watkinsiana growing on a brush box (Lophostemon confertus)3. Ficus watkinsiana on Syzygium hemilampra [Acmena hemilampra], Iluka, NSW.4. A young Moreton Bay Fig starting life as an epiphyte in an Auckland, NZ park5. Base of a large specimen of Moreton Bay Fig, growing in the Jardin do Utramar, Bazi, Portugal

1 ANBG, Growing Native Plants, Platycerium superbum, at https://www.anbg.gov.au/gnp/interns-2006/platycerium-superbum.html2 Introduction to Australian Orchidaceae https://www.anbg.gov.au/cpbr/cd-keys/orchidkey/html/intro-c.html

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RETURN TO PATH RUNNING ALONG EDGE OF RAINFOREST, HEAD DOWN PATH, PASSING ON THE RIGHT, BEFORE THE TWO BENCHES ON PATH…

YOUNG STRANGLER FIG ON A STUMP Strangler Figs start life as epiphytes! Thus termed hemi-epiphytes. Growth

o Deposited high in the canopy of a rainforest tree by bird, the seed germinates and the seedling attaches itself to the host tree.

o It obtains water and mineral nutrients in the same way as other epiphytes and sends down aerial roots.

o The roots eventually reach the ground and thicken, supporting the canopy. o They grow massively and end up killing the host tree, not by consuming it or

poisoning it but effectively by strangling it. Hence their common name.o In horticulture, strangler figs can be grown independently as free-standing trees.

Australia has about 40 species of the genus Ficus, of which a number are strangler figs. These include:

o Moreton Bay Fig, Ficus macrophylla (Wide Bay-Burnett region, Qld to the Illawarra, NSW, also Lord Howe Island)

o Watkins’ fig or Green-leaved Moreton Bay Fig, Ficus watkinsiana (North east Qld, south east Qld, north east NSW).

…AND AFTER THE TWO BENCHES, PAUSE AT THE FALLEN LOG…

SEED REGENERATION IN RAINFORESTS1 – COMPETITION

RAINFOREST SEEDS This fallen log represents an essential part of Rainforest processes RF seeds don’t survive long once fallen Germinate rapidly / eaten by animals / rot quickly / lose viability For ANBG Seed Bank they’re a problem - Recalcitrant! Seedlings survive at a very early stage & low light levels – “suspended animation” for years Canopy break, e.g. fallen log, the increased light starts rapid growth till canopy cover

restored NB an exception – Pioneer plants, e.g. A. melanoxylon, seeds survive as usual very

important

RE-VEGETATION GROUPS IN FAR NORTH QUEENSLAND Use this knowledge in the way that they propagate plants

o Rapid collection of fresh seedo Germination in shallow trays of low nutrient soil and kept at low light levelso Can keep large numbers of seedlings in small nurseries at a manageable cost for

considerable periods of timeo Preparation for suitable planting conditions by potting up into larger pots with

better soil and increasing lighto Ensure enough plants of varied species to re-vegetate damaged habitat or create

corridors between existing habitat areas

1 Robyn Black, ANBG Volunteer Guide, pers.comm.

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EXIT RAINFOREST JUST BELOW SEED BANK, CONTINUE WALKING DOWN TO CLOCK. AS WALK ALONG TALK ABOUT ANY OR ALL...

Point out features of a Rainforest not already mentioned, repeat information or add o Armillaria is cause of damage to flowering trees within the Gully, Tree Ferns not

affected by ito Pioneer plant A. melanoxylon has been planted here to begin regenerationo Some of the black wattles are self-sown demonstrating the longevity of their seed,

the importance of variability within a species and the early stages of RF regeneration

Give a short summary of the types of symbiosis seen today

Discuss the impact of humanso Allelopathy: refer back to information under Stop 8

Thank you for coming

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Documents

€¦ · Web view2021. 3. 21. · SYMBIOSIS: THE ART OF LIVING TOGETHER. Theme. This Special Guided Walk was planned to run in conjunction with a performance, “Symbiosis”, by