Greg's Indigenous Plants & Landscapes

Environmentally friendly landscapes.

" The exotic vegetation that replaces indigenous plant communities in urbanising regions, disassociates us from the rhythms and diversity of the native landscape
and a sense of the place; and we are the poorer because of it."

Michael Hough, Professor of Landscape Architecture, York University, Canada

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Scuba Diving

I recently purchased a new scanner, that is capable of scanning photographic slides and negatives, in order to digitise a number of slides from scuba diving trips that I undertook in my younger days. 

So I thought I would share a few of them here.

The Cod Hole near Lizard Island QLD

My brother with two of the Potato Cod. These two had just left a 'clean station' and were in some sort of an ecstatic trance, totally unaware of my brother's proximity and touch. When they came out of it and realised my brother was touching them, they darted off in shock.

My brother being dive bombed by a huge Maori Wrasse as he was feeding the Potato Cod. The Wrasse was hovering above my brother for some time watching and I could see it was up to something, so I was ready when it made its move. My brother later reported that it was like having your hand in a vice as it was slammed shut. They actually have quite small teeth that don't do much damage.

Moray Eel being fed by our dive guide. You need to be careful when feeding these as their backward pointing teeth would shred your flesh to the bone and they are very short sighted

Mount Gambier Sink Holes

10-80 sink hole - named after the poison 10-80.

My dive buddy exiting the 'railway tunnel' in 10-80 sink hole.

My dive buddy exiting the bottom of the 'Cathedral' in Piccaninnie Ponds, so named because the underwater cavern is as big as a cathedral.

Looking straight up from the bottom of 'The Chasm' in Piccaninnie Ponds, after exiting the 'Cathedral'. We were at a depth of about 40m, which is close to the maximum depth you can go safely on compressed air and still have a reasonable amount of 'bottom time'. Much deeper requires special gas mixes with reduced oxygen, as the oxygen content of compressed air starts becoming quite toxic to the lungs at depths of greater than about 50m.

This is my dive buddy doing some precautionary decompression, before surfacing, at the top of 'The Chasm'.

Osprey Reef in the Coral Sea

My brother watching the shark feed in progress. The dive boat crew were sending fish carcasses down the anchor line to the assembled White Tip Reef Sharks that were in a feeding frenzy. The show little interest in divers and probably view us as just another big fish and possible threat to them. My brother ended up being jostled by this shark after it tore off a large chunk of fish off and tried to make his escape before the others could pinch it off him.

Skull Rock Sea Lion colony off Wilson's Promontory

This particular colony of Australia Sea Lions are particularly naive towards humans and therefore very 'tame'. It is the juvenile individuals that show the greatest interest in divers. As we cruised up to the colony there was a huge stampede of sea lions into the water and they then proceeded to chase our boats as we identified a good place to drop anchor.

They are actually very difficult to photograph since they tend to stick their snout in the camera lens and hang on to your arms, fins, snorkel and various other dive equipment and body parts. They have been known to steal things from divers and then play with them. It is a matter of just clicking away and then sorting out the worth while photos from the crappy ones later.

If you hold out your hand they will nibble your fingers and their teeth are exceptionally sharp, more like those of a cat than a dog.

Yongala Wreck of Townsville

This steam ship went down without a trace in the early 1900s with the loss of all passengers and crew. It where abouts remained a mystery until an Australian Navy ship stumbled upon the wreck in the 1970s while conducting exercises.

The remains of many of her passengers and crew remain inside the wreck which is a designated grave site. It has become an artificial reef and fish magnet although, due to its relatively close proximity to the shore , it is in quite murky water.

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A Guide To Grassland Restoration

This guide is specific for the types of remnant grasslands that you are likely to find around the northern suburbs of Melbourne. It may be applicable to other types of grasslands in other areas, but that will have to be up to those with experience working in other types of grasslands. The grasslands are dominated by Themeda, Bothriochloa, Dicantheum, Austrostipa and Austrodanthonia in varying proportions, with a wide variety of other herbs etc scattered through them.

I am going to add to this as I think of things as it it fairly difficult to grasp all of have learned through my experience in one go.

1:1000 Glyphosate

Applying dilute glyphosate is a brilliant technique for selectively eliminating a wide range of weedy annual grasses from among perennial native grasses, most particularly the C4 grasses but also many of the C3 grasses such as Austrodanthonia. 

We have found that you can overspray Bothriochloa, Themeda, Dicantheum, Austrostipa, and Austrodanthonia caespitosa when ever they are largely dormant with only minimal detrimental effect. Generally their foliage is burned back but nearly always seem to recover quickly particularly if you slash them back a little later on. Dormancy can include winter dormancy for the C4 species or simply drought induced dormancy for all species, i.e. we have over sprayed Themeda etc in spring and summer while there was little viable foliage on them and they recovered as per usual.

The weedy annual grasses rarely survive such treatment. However spraying herbicides at below the recommended dilution can promote the development of glyphosate resistant varieties so you need to be on the look out for this. Combining dilute glyphosate spraying with traditional slashing, where necessary, to prevent seed set among the weedy annual grasses is a good idea.

Robust native plants like Atriplex, Einadia, Acaena, Convolvulus and perennial Wahlenbergia etc can also be over sprayed without causing lasting damage to them.

If you are unsure about using this technique then it is a good idea to trial it in small areas at different times of the year and under different rainfall conditions.

Expendable Natives

When you have a grassland containing robust natives like Atriplex, Einadia, Acaena, Convolvulus and perennial Wahlenbergia, and that is also heavily infested with various Brassica such as Wild Mustard, then these native plants are fairly expendable.

These native herbs etc have large tap roots or tuberous roots and are likely to survive even if over sprayed with broadleaf specific herbicides like MCPA or KambaM at the recommended dilution. If not then they all self seed vigorously and are likely to be replaced in time and under the right conditions with abundant seeds lying dormant in the soil. But clearly, once you get the Brassica under control, you need to keep it that way so as to avoid having to do this again and thus drawing down of the native seed bank to much. 

It is also a fairly easy matter to collect seeds from these species and scatter them over the area that you have sprayed and thus effect  rapid replacement of any plants that you end up killing. It would be nice if you had the resources to hand weed in and around every patch of the above natives but in this industry that is rarely the case.

I would recommend against trying this with woody weed killers like Garlon and Esteem/Brushoff as you are much more likely to kill them outright.

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Why did Australia become fire prone?

Mud cores have been taken from various locations around Australia like the continental shelf of the QLD coast, lake George and a volcanic lake on the Atherton table land in QLD. The further towards the bottom of the mud core you go the further back in time that those particular sediments were deposited. The mud also contains the pollen grains of plants and so, by examining the types of pollen present in different sediment layers, you can infer the dominant plant genera that were growing in Australia at the time.

The pollen of all plant species within a particularly genera are always very similar and distinctive. For example the pollen of all Eucalypts is very similar, even those Eucalypt species that have long since become extinct.

The evidence points to the fact that much of Australia was blanketed in various types of rainforest up until quite recently. The precise time is under debate within the scientific community and estimates vary from 100,000 years ago to as little as 38,000 years ago. Familiar 'temperate rainforest' blanketed the wetter niches of the Australian landscape but the majority of it, including the dry western flanks of the Great Dividing Range, was blanketed in a very unusual type of rainforest. It is called 'dry rainforest' and it was dominated by fire sensitive conifers from the Araucaria genus. 'Dry rainforest' looks more or less the same as a 'temperate rainforest' except that the component species were able to survive in much drier conditions. Eucalypts were present in Australia, probably in fire prone heath lands, but were far less prevalent than they are at present. 

The only remaining tiny remnants of these 'dry rainforests' are found in the midst of Brigalow Scrubs on the western slopes of the Great Dividing Range. Brigalow Scrubs are extraordinarily resistant to fire and in the midst of these scrubs small patches of 'dry rainforest', as well as other very unusual and fire sensitive plant communities, are protected from bushfire that ravage the region from time to time. Sadly Brigalow scrubs themselves are extremely endangered due to past land clearing to make way wheat crops.

At the time that much of Australia was blanketed in rainforest, both temperate and dry, Australia's megafauna was at its zenith. Herds of Diprotodons and short faced kangaroos roamed the plains and forests and they were hunted by Tasmanian tigers, marsupial lions and even carnivorous Kangaroos. There were also familiar Eastern Grey Kangaroos but back then they were about 30% larger than today's Eastern Grey Kangaroos and stood about 3 metres tall.

Then abruptly, at some point between 100,000 years ago and 38,000 year ago, the number of microscopic charcoal particles present in the sediments of many of the core samples dramatically increases. There after Eucalypts become by far the dominant plants along the east coast of Australia. At the same time or soon after Australia's megafauna became extinct and mangrove pollen makes a sudden appearance in the sediments. Mangroves thrive in tidal mud flats produced by accumulated sediments eroded from hills and mountains and transported by rivers. 

What happened in Australia at this time to cause the extinction of our megafauna and such a dramatic and rapid shift in Australia's flora?

It is widely accepted that Aborigines have been present in Australia for at least 40,000 years. But many scientists believe it is likely that they arrived in Australia perhaps as much as 60,000 years ago, although palaeontological evidence is very rare and inconclusive. Either way it is a reasonable proposition that the the arrival of Aborigines in Australia, the extinction of our megafauna and the dramatic shift in Australia's ecosystems were not coincidental.

In many regions of the world there is sufficient palaeontological evidence to suggest that the much of the megafauna of those regions became extinct soon after the arrival of humans beings. In short the number of human beings increased rapidly due to the abundant supply of meat, resulting in over exploitation of the megafauna to feed the growing number of mouths and eventual extinction of the megafauna. This often happened in a very short space of time, geologically speaking, perhaps as little as 200 years in some cases. 

The most recent example of megafauna extinction, for which there is abundant archaeological evidence, is the extinction of the Moa in New Zealand brought about by the Maori. There are sites in New Zealand that consist of tens of acres covered in the bones of tens of thousands of Moa. There are ancient ovens that contain cooked Moa haunches that the Maoris of the time never even bothered to open. The Maoris only ate the haunches and left the other parts to rot. So when Moa meat was abundant the Maoris were incredibly wasteful. When the British arrived Maori civilisation was in terminal decline with chronic food shortages and a widespread culture of theft, violence, cannibalism and warfare. Is this sounding vaguely familiar in the context of contemporary western economic civilisation? We seem to be experiencing increasing crime and ethnic tension within our societies along with increasing warfare between neighbouring nations and between nations and their own ethnic minorities, often over resources like land and water?

In Africa large herds of large herbivores consume enormous quantities of vegetation and convert it to dung. The dung is quickly incorporated into the soil, along with abundant plant nutrients, by hordes of dung beetles. This is a closed and very productive ecological system where nutrients are cycled very rapidly and little if any nutrients are lost from the system. This is much like a modern economic system, with trade barriers, where money is continually cycled through the economy and makes it vibrant and productive.

If the large herbivores are removed then vegetation quickly builds up and grass lands give way to woodlands and scrubs and then forests. Trees and shrubs continually shed their leaves and branches while dry uneaten grasses foliage continually builds up. Sooner or later lightening will spark a fire that rapidly gets out of control with so much fuel on the ground. Fire replaces large herbivores as the consumer of vegetation, however it is far less efficient because so much of the nutrients in the plant matter are lost in the smoke that drifts away.

Could it be that the the ancestors of Aborigines arrived in Australia about 100,000 years ago and quickly hunted the megafauna into extinction? Tim Flannery thinks this is very likely.

If so then with the megafauna gone there was nothing to consume the vegetation which kept growing until vast quantities of fuel built up. When lightening ignited fires these would have spread rapidly out of control over vast areas with so much accumulated fuel. The regular fires would have driven the fire sensitive 'dry rainforest' plants into rapid decline and opened vast new opportunities for the fire loving Eucalypts which then proliferated equally rapidly. 

Could the sudden appearance of mangroves indicate that, at the time that massive wildfires were ravaging the ancient rainforests and before Eucalypts had dominated the landscape, there was an episode of massive erosion on the exposed eastern flanks and foot hills of the Great Dividing Range  resulting in massive quantities of sediments being deposited in the river estuaries? Is this why Australia's top soils are generally so very thin?

The nutrient value of  Eucalypt foliage is very much less than the foliage of 'dry rainforest' plants and there were only a handful of marsupial herbivores, the ancestors of possums and koalas, that could eat it. The closed and efficient nutrient cycle of Australian ecosystem was broken to be replaced by a very much less efficient one where fire was the key to releasing the sparse nutrients held in Eucalypt foliage. But nutrients were continually leaching out of the Australian ecosystem with the smoke of the fires, resulting in soils becoming ever poorer. Any chance that 'dry rainforests' could make a major come back were lost long ago.

The ancestors of Aborigines would have been in dire trouble. They would have seen their traditional food sources going up in smoke with the dry rainforests at an alarming rate to be replaced by inedible Eucalypts. The megafauna was extinct or almost so, with only small to medium size game remaining. But that would have been driven away from their homelands as vast areas of it burned to ash.

Over time the Aborigines realised that they could control the fire / fuel build up cycle by burning the bush at safe times of the year before fuel loads built up to dangerous levels. In so doing it suppressed the growth of forest and scrub and promoted the growth of herb rich grasslands that in turn attracted small to medium herbivores, like kangaroos and wallabies, that were able to proliferate to a greater extent than they otherwise would have. The intimate relationship between our flora and fauna and fire had begun and eventually gave rise to the incredible biodiversity that we are now custodians of. 

The Aborigines learned the lessens of unsustainable growth and consumption well and transformed their culture into one that as eminently sustainable and has lasted, largely unchanged, for at least 40,000 years. The future eaters had become experts in extracting a living from Australian ecosystems while preserving and enhancing biodiversity. Johnny come lately Europeans had the poor grace to regard Aborigines as being primitive and inferior.

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A word from Chris McLean

According to Chris McLean from the Centre for the Risk Management of Bushfires at the University of Wollongong:

"There are a number of studies that have occurred throughout Australia on fauna recovery post fire yet unfortunately control impact studies (where monitoring had occurred before and after wildfire) are a little scarce. One of the most famous studies have occurred in the heathland of Nadgee Nature Reserve since the early 1970s by Dan Lunney, Harry Recher and other associates with monitoring mainly concentrating on small mammal populations. The area experienced a high severity wildfire in 1972 (2 years into the study) and a low severity wildfire in 1980 with no fires since. Small mammals have been continuously sampled on the site since 1972 and their population trends are summarised by Recher et al in the current issue of Wildlife Research. While undertaking his PhD at the Myall Lakes in northern NSW, Barry Fox's study site experienced a wildfire thus presenting a nice opportunity to document small mammal recovery post fire (documented in papers in the early 1980s with one in Ecology in 1982 if my memory serves rightly). The conclusion to these studies from infrequent high intensity wildfires in heathlands (ie 'flammable environments') is that populations of common species such as Brown Antechinus/ Agile Antechinus and Bush Rat/ Swamp Rat  peak at around 7 years post fire and decline thereafter. Having said that several 'threatened' rodent species (New Holland Mouse and Eastern Chestnut Mouse) reach a maximum population density within 2-3 years post fire and decline thereafter and are probably threatened by infrequent fire. Several reviews on small mammal fire ecology have been completed, for example Liz Sutherland and Chris Dickman in Wildlife Research around 1999/00 but I would also have a look at Peter Catling's critisism/ critique of frequent hazard reduction burning in the 1st edition of The Conservation of Australia's Forest Fauna (ed D Lunney, published by the RZS NSW).

More importantly I suppose for the victorian Mountain Ash/ Alpine Ash/ Messmate forests and fire recovery a great deal of work has documented the requirement of these communities of infrequent high severity fire (ie crown fire) to regeneration (ie to stop them becoming rainforests). Dave Ashton completed a PhD around Kinglake in around 1964 and Malcolm Gill (CSIRO) has worked extensively on the ecology of Alpine Ash. Anyway back to fauna responses. Brendan Mackey, David Lindenmayer and associates published a book by CSIRO publishing in around 2001/02 called Wildlife, fire and future climate based on fire ecology of Mountain Ash. This book might be out of print but good uni and TAFE libraries should have a copy. It contains details of modelling of mountain ash hollow dynamics post fire and lots on the leadbeater's possum, a bit of a conservation paradigm as it requires hollows but also Acacia in the understorey thus fire events are good but also bad. There have been a number of studies in Mountain Ash and other recently burnt vegetation types, for example one in Wildlife Research by van der Ree and Loyn (from around 2000) that compared Greater Glider and Small Eared Possum abundance among sites last burned in 1939 in comparison to those last burned in 1983. There were more Greater Gliders in 1939 sites yet due to a lack of fire severity work I wouldnt conclude anything further on it.

So I guess in conclusion with fires there are winners and their are losers. Certain species are sensitive to frequent fire while others relish frequent fire. Unfortunately we cant cater to all species with single fire regimes and at best we can probably only cater to species that are easiest to monitor, represent the greatest ecological importance or are flagship species (ie cute and cuddly)."

I would add to this, that as long we don't put all or prescribed burning eggs in the one basket and implement a large variety of prescribed burning regimes in different regions and different areas within given regions, then we stand a reasonable chance of preserving even the non-flagship elements of our fauna in the long term.

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Environmental Weeds & Bushfires

After you have worked in the bush for a year or more you start to notice a fundamental difference between they way exotic environmental and noxious weeds respond to rainfall and the way in which most native plant species respond.

The seeds of all environmental and noxious weeds  germinate rapidly with the least little bit of rainfall, grow very quickly and then, once the rainfall dries up, the weeds rapidly dry out and leave dense thickets of very dry vegetation. Most native plants show virtually no response to brief and transient showers and their seeds will only germinate when there is sustained and substantial rainfall. This is why it takes a lot of time and effort to restore infested remnant bushland.

Consequently intact native bush land is often quite open with surprisingly little ground storey vegetation while weed infested native bushland is dense and often impenetrable. So it should be fairly obvious that weeds make a significant contribution to the propagation of bushfires at ground level.

You also notice in weed infested bushland, that when you remove large Eucalpyts, you often get a rapid boom in weed growth. More sunlight reaches the ground and the Eucalypts roots no longer steal water and nutrients from the weeds.

So the frenzy of tree removal that is currently taking place on the urban fringes of Melbourne in response to the 2008 bushfires may actually contribute to making the bushfires worse in two ways. By increasing their intensity by improving weed growth and thus the density of the fuel load at ground level. And by increasing their speed of bushfires by removing the only thing that can slow down strong winds - large trees.

So I would recommend that, if you are participating in this tree removal frenzy, you take a step back and think a little more carefully about the possible unintended consequences of what you are doing.

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