Grazing Swamp Wallabies are a huge hurdle to successfully growing new trees in sections of Tarra-Bulga National Park. Hard lessons have been learnt, 1000’s of trees have been planted, but experience has shown that even if they are hidden or planted among unpalatable species the Wallabies will eventually find them and eat them. Regular tree-guards have proven to be of little use, they may protect the plant for a short while but Wallabies will chew any growth at the top of the guards that they can reach, the plant will remain stunted and eventually die. A commercially available Wallaby repellent mixture can be sprayed on new growth to protect it, but that is labor intensive and requires regular follow up to have any chance of success, not a viable task in our situation with limited time and rough terrain to encounter . The only strategy that does seem to work for us is to use large wire mesh tree-guards which are expensive and very labor intensive to install and eventually remove once the trees have grown big enough..
Why do we think direct seeding might be a solution? Nursery grown tube-stock are generally grown in ideal conditions, with fertiliser, controlled sunlight and regular watering, as a result the leaves are highly palatable. Plants that germinate from seed on sites should be tougher, slower growing and as a result have less tasty foliage. Mountain Ash along with other species of Eucalyptus seeds are very small, one gram of Mountain Ash seed contains nearly 200 viable seeds. For our trial we have 390 grams of Mt Ash seed, if all of them germinate we would have almost 80,000 seedlings scattered over the site. That is clearly an optimistic outcome but hopefully we can get a good germination strike rate and some of those tiny little seedlings can overcome the Wallabies and other forces of nature to successfully grow into mature trees. We will keep you posted.
Mountain Hickory Wattle, seed should still be good even though it is 8 years old.
Mountain Ash (Eucalyptus regnans seed) potentially 78,000 trees in this bag.
A recent post reporting on the results of our camera trap monitoring program for 2013, identified a trend with Swamp Wallabies where numbers photographed by across the park by camera traps dropped very sharply after July. We have no real explanation for this, but as we gather further data, it will be interested to see large annual fluctuations in the Wallaby count continues.
We had an inquiry as to whether it was more common to record Swamp Wallabies in daylight or during the night-time, which is an interesting question and one which is easy to work out from our database. So after crunching some numbers here are some answers, not just for Swamp Wallabies, but for all our commonly recorded species.
Swamp Wallaby triggers are fairly regular at any time of day or night, they do seem to slow down as you might predict in the middle of the day, but then fire up to have their peak numbers in the early evening.
Although it is not particularly uncommon to see Wombats out during the day sometimes, perhaps surprisingly we have never had one trigger a camera between 8am to 4pm. They seem to have peak activity in the evening and another peak around 4am.
It’s no surprise that these Bandicoots are rarely seen, although we get fairly regular photos of them, they seem to have a definite peak of activity between 2am and 4am.
The graph shows here that there is never any time of day for animals to be complacent. Foxes can be active at any time of day, seems like they are marginally more common at night. Also have data on Feral Cats, they too can be around at all hours, but seem less likely than a Fox to be around in daylight.
Lyrebirds in Tarra-Bulga obviously need to make the most of the daylight hours. It seems there is a slightly greater chance they will be snapped by a camera in the morning, but overall any time of the day is good for them.
Here’s a breakdown for you all showing the species that triggered our remote cameras last year. The lower number of detection in the later part of the year can be explained by a few issues that we had with dodgy SD cards causing the batteries to conk out prematurely. Can’t explain why the Wallaby numbers vary so much each month. Some of the other species e.g. Lyrebirds, seem much more evenly represented over the year.
Breakdown of Remote Camera
Triggers – Tarra Bulga National Park 2013
Took the trek in to check on the progress of this site recently. Part of our strategy against Wallaby predation, as well as using big guards, had been to plant Mountain Ash among some of the large dead Sycamore Maple that had been fallen at the site. Initially it had seemed that this plan had worked a treat, but we had underestimated the Wallabies and last time I visited the site (6 months ago) the pesky Macropods had pretty much munched all of the carefully placed plants; all but confirming that our conventional method of using big wire mesh tree guards is the only way to beat these beasts.
Even species that were meant to be Wallabies least preferred food such as Olearia lirata (Snowy Daisy-bush) were being heavily chewed.
On this visit things were actually looking a little better and it seemed that there had been some recovery of planted tubestock; although the ones not properly guarded were not much bigger than when they were planted over 18 months ago.
The Sycamore Maple which had once completely covered the 2ha site is also not giving up without a fight. A clamber around the site revealed many seedlings emerging and we as a group will focus on removing them before they become large feral trees. On the plus side there is mass natural regeneration of native understorey occurring with an impressive diversity of species, including plenty of Wattles; that have germinated without the aid of fire. The Maple logs that we left in-situ have been a massive bonus because the micro-climate they created has been perfect for fern regeneration, which is happening all over the site. The logs are breaking down quickly now with a variety of Fungi helping the process. We will have another planting day later in the year on this site (using the big Wallaby guards) so keep a look out for it if you are keen to lend a hand.
Overall view of site, showing the mass regeneration of shrubby understorey.
Hiding among the undergrowth a planted Mountain Asf
Snowy Daisy-bush showing the impact of Wallaby grazing.
New Sycamore Maple Seedling emerging.
Rainbow Fungus – Trametes versicolor aiding the decay of the Maple logs.
Logs left on the site aiding fern regeneration
Another log microhabitat providing a great site for fern regeneration.
Prickly Coprosma full of red berries
Lots of Kangaroo Apple with ripe fruit at the site.
Naturally Regenerated Tree Lomatia
Pine Tree that should have been dead by now.
No shortage of Sycamore Maple on site to be found and exterminated.
This post is a summary of the Remote Camera Monitoring results over December and January 2012/13
Camera 1 – Still out of action after it was attacked by an aggressive lyrebird.
Camera 2 – Located in mature Wet Forest in the Tarra Valley was quite a prolific site, with the camera picking up lots of small birds e.g. White-browed Scrub Wrens and Bassian and Grey-Shrike Thrushes, as well as mammals such as Antechinus and Long-nosed Bandicoots, unfortunately there were plenty of Foxes and a Feral Cat present. Also plenty of Wombats, Wallabies and some Brushtails.
This vision of a mother Swamp Wallaby (Wallaby bicolor) and her young one was snapped at one of our monitoring sites in the Tarra Valley section of the park. The camera was ideally located to catch the action.