Climate Change Threats to Native Species
by
Naomi Hall
Part of the Blackburn Lake Walk and Talk with Eastern Climate Action Melbourne March 2015
I want to talk to you today about how climate change is affecting all the other species that we share
the world with, because our decisions affect them all.
This lovely park at Blackburn Lake is a good place to start talking about this, because it is a place
where for many years local community volunteers have been working to preserve and restore the
bushland, in conjunction with government. And the benefits of their work are enjoyed by our native
animals as well as us.
Blackburn Lake is the starting point for Gardiner’s Creek, which is a significant waterway for the east
of Melbourne. From here it does a big loop through the east and southeast and joins the Yarra River
in Hawthorn. Within the city of Whitehorse there are further parks of restored native bushland
lining the creek down to Middleborough Road, which make up the Blackburn Creeklands.
Animals that use this habitat include birds, bats, possums (marsupials), insects, fish and frogs
(amphibians). They represent most of our native animal groups.
I want to talk about what is happening to animals as the climate heats up, and I’ll also touch on some
of the issues for creatures in the sea, particularly around the Australian coastline.
Probably the most serious issues for animals here are heatwaves and fires.
How do these animals cope with extreme heatwaves?
One of the animals for whom the effects are obvious is the flying fox. You will all be familiar with the
sight of these bats flying over Melbourne in the evening. These are animals that have an important
role in keeping our eucalypt forests healthy, because they pollinate the flowers and disperse the
seeds.
Early last year (2014), 9,000 flying foxes died in Queensland following a heatwave. The same thing
happened in Victoria in 2009, when around 5000 deaths were recorded. Flying foxes aren’t able to
survive more than about two consecutive days over 40 degrees, and because they are in big flocks,
they show us what may be happening to other animals.
We know that possums die from the heat - last year some were found on the tracks in this park
following a severe heatwave. We also know that birds die but it is not so obvious because they are
not usually in flocks.
And bushfires of course are even more deadly.
Larger animals and birds can possibly run or fly away; some might find a safe place underground, like
wombats and snakes. But animals that get caught up in trees like koalas and possums, and small
birds that don’t fly very far, like the blue wren, can’t escape.
Rising temperatures are affecting animals all over the world in a number of ways.
Most living species can’t evolve fast enough to adapt to a hotter climate so they have to migrate to
cooler conditions. This means moving closer to the north or south pole, or higher up mountains.
Neither of these options is going to work for very long. As we know, the polar bear is in trouble at
the north pole with the huge melting of ice sheets.
And when there is nowhere else to go, the species will become extinct.
There are many problems in species migrating. They move into areas where other animals already
live, so there are problems with food supply and establishing breeding territories. Also diseases and
parasites which the migrating animals bring to the area can jump to the new hosts, and cause rapid
spread of infectious diseases.
For us in Victoria, mosquitoes moving further south as the climate warms means exposure to
diseases previously confined to the tropics, such as dengue fever.
And now I want to make a quick jump from Blackburn Lake to the oceans.
Heat waves also happen in the ocean, and in W.A. in 2011 there was an unprecedented marine heat
wave which affected 2000 km of coast from the Ningaloo Reef in the north down to the Southwest
corner of W.A. The ocean temperature rose by more than 2 degrees above the seasonal average for
10 weeks. In some places it rose 3-6 degrees for several weeks.
The heat killed off underwater kelp forests, abalone, crayfish, crabs and fish, and bleached coral on
the Ningaloo reef.
In the four years since, the sea life has not recovered.
A commercial abalone fishery which was decimated, is trying to recover by restocking, but time is
needed for this which we might not have.
The heat wave was driven by a La Nina event on top of the already existing rise in ocean
temperature. This was the same La Nina event that caused the extreme floods in Queensland in
2011 which Peter (another speaker) has mentioned.
Now scientists project that as our temperatures continue to rise, these extreme La Nina events,
which used to occur every 23 years, will now occur every 13 years. On top of this, increasing acidity
in the oceans means that calcium is becoming less available to shellfish to make their shells. This
may also affect their recovery.
Around Australia’s coastline we have tropical waters and temperate waters. Kelp forests grow in
temperate waters, and they are the feeding grounds, nurseries and breeding grounds for a large
range of temperate marine life that we depend on including many commercial fish and shellfish,
such as Abalone and Wrasse.
In response to climate change all the fish around Australia are basically moving south.
And as the tropical fish, many of which are herbivores (plant eaters), are able to move down into the
kelp forests, they can eat them out very quickly, with devastating results for all the temperate
species.
And this will affect our commercial fisheries.
Dangerous pest species like the Box jellyfish are migrating further south as well, which has
consequences for our safety of the beach.
Conclusion:
All these species that are affected by climate change can’t speak up for themselves, and they can’t
vote.
What’s more, as part of the same ecosystem, if they are damaged, so are we. So it’s up to us to take
action.
We don’t have much time, but we do have enough to take action, and we need to use that time to
achieve the best outcomes possible.