Discovering the last sheoak of Walker Swamp

If you pay attention out at Walker Swamp, some very interesting ecological processes and transitions are underway. This little update is about letting the pictures do the talking… so let’s go for a stroll and read the landscape together!

First up, let’s start with the big picture, and this oblique aerial view. Looking over Walker Swamp from north to south, this is a perspective you may not have seen before. The good news for 2021 is that after a very mild summer and autumn, this is the driest you will see Walker Swamp this year – which is not dry at all – because it is still very wet out there!

June 2021 and Walker Swamp is primed for the season ahead. Photo: Mark Bachmann

In the foreground is the recreated northern basin at Walker Swamp, restored by back-filling the drain through the bed of Walker Swamp (the strip visible between the wetlands). The wetland vegetation response in this northern basin has been remarkable considering it had been entirely planted to blue gums and its hydrological functionality was only restored 2 years ago. On the right had side of the image above, you will see the northern levee bank, which has allowed us to restore Walker Swamp without causing any detrimental impact to our farming neighbours to the west. Let’s take a closer look at this spot on the ground…

The northern levee bank, looking south. Photo: Mark Bachmann

If you were wondering why the colour of the patterns in this area from the air look so different either side of the levee bank, now you can see why! On the recently restored eastern (left) side of the levee bank, sustained inundation has eliminated pasture grasses and is giving wetland plants the competitive edge, while also providing more open mudflats for wading birds to rummage around in looking for tucker as the water level recedes each year. If you look closely you can even see some blue gum logs and debris scattered on this side where the plantation used to be. To the west (right) side of the levee bank and, despite being a naturally soggy area, the introduced pasture grass species still have the competitive edge.

This impact of inundation on ground cover and competition is also shown below, from a little further south adjoining the main Walker Swamp waterbody. This photo shows the natural wetland edge zone between current low water mark (left of image) and the newly restored full supply level (right side of image) where water reached for the first time in spring 2020.

The wetted edge of a newly restored Walker Swamp – a zone where we expect a lot of rapid changes in vegetation to occur. Photo: Mark Bachmann

The band of exposed wetland bed in between is a zone where we expect to see rapid changes in native vegetation cover unfold over the years ahead. Inundation reduces competition and will give wetland flora the edge to bounce back. This area is only one year into the restoration process, and again you will notice a large amount of woody debris from the former blue gum plantation in this area. Notice how the old Red Gums were telling us all along where the old high water mark used to be!

And speaking of Red Gums… we have a few recruits!

Red Gum regeneration en masse near high water mark, after restoration achieved the first sustained inundation event at Walker Swamp in approximately 70 years. Photo: Mark Bachmann

One of the wonderful things about having Red Gums dotted across the floodplain at Walker Swamp is that they are capable of immediately taking advantage of the break in the long artificial drought, with a mass germination event occurring in many areas around the newly restored high water mark. Indeed this early success means we are going to have to think pretty quickly about whether we want to end up with a Red Gum forest, or implement management strategies to maintain a more open woodland structure.

Indeed, one of the potential management strategies is the use of fire – a tool used for millennia and with precision by Aboriginal people to manage the landscape. So it will come as no surprise that where we have burned off some of the old piles of debris from the blue gum harvest, that the seedbank has been stimulated by fire, in this case blackwoods – as shown below.

Blackwood seedlings emerge from seed, stimulated by fire. Photo: Mark Bachmann

The other place that I have started to notice blackwood seedlings coming up randomly, in the absence of fire, is in the former blue gum plantation areas… or is it random?

Blackwood seedling, next to a blue gum stump but far from the nearest mature blackwood tree. Photo: Mark Bachmann

The interesting thing about this, is that these seedlings are popping up all over the place and often long distances to the nearest mature (seed producing) blackwood tree.

And notice how the seedling is next to a blue-gum stump? When you wander around, this exact scenario is commonly repeated, indicating that the short lateral branches of the plantation blue gums, while they were still standing, were actually providing perches for native birds to stop and disperse seed through the property (deposited in their droppings) because we do have mature blackwoods within flying distance.

Now that the blue gum plantation is gone, in areas above high water mark on the central lunette, these blackwood seeds are germinating in response to the increased light and water coming their way since the artificial canopy was taken away. What a fascinating thing to witness. And so, despite the many challenges caused by the blue gum phase at Walker Swamp, that cloud does have a small silver lining.

But perhaps the highlight of the day was coming across a relic of another time, and a reminder of floristic diversity now mostly lost from the western Victorian plains. This is the last Drooping Sheoak of Walker Swamp…

The last Drooping Sheoak of Walker Swamp. A relic of another more floristically diverse time. Photo: Mark Bachmann

A grand old tree hanging on against the odds, it really stands out because I had never seen one on the property before. Like tree-form Silver Banksia plants, these fire sensitive and highly palatable species (to grazing livestock) – which were formerly much more common across Victoria – are now lost from so many areas that they have their own very special Friends Group interested in their preservation. If you would like to learn more or contribute to their fantastic work, then please visit the Friends of the Forgotten Woodlands website.

Finally, a photo that gives us hope and faith in the long-term recovery potential of this landscape. The northern edge of the Walker Swamp floodplain, bouncing back…

Spontaneous regeneration of native rushes, sedges and trees at Walker Swamp in former blue-gum plantation. Photo: Mark Bachmann

This spontaneous regeneration of native rushes, sedges and indigenous trees at Walker Swamp occurring in former blue-gum plantation is entirely natural – nothing in this image was planted. Imagine what this scene will look like in 5, 10 or 20 years?

Yes, we can safely say that this project is on the right track! And it wouldn’t be happening without those of you who helped us make it a reality, so thanks for joining me on this virtual stroll across the floodplain.

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is also grateful for the support of the following partners who supported us in bringing the vision for Walker Swamp to life:

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Mark Bachmann