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.
Top
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. Top
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.
Top
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. Top
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. Top
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