Tolga Bat Hospital - Tolga Scrub
 


The Tolga Scrub is one of the last remaining fragments of the critically endangered type 5b or Mabi rainforest (Complex Notophyll Vine Forest) on the Atherton Tablelands. There is about 2% of original Mabi forest left. It once covered areas north and west of Malanda, on fertile basalt soils of the Atherton Tablelands, where the annual rainfall is 1300 - 1600 mm.

Tolga Scrub is on the very north-west boundary and in the driest part of Mabi distribution. Mabi is characterised by the presence of scattered, mainly deciduous emergent trees up to 45m tall, heavy leaf fall during times of moisture stress and a well-developed shrub layer. It is the most drought resistant type of rainforest in Australia. Widespread clearing of Mabi has resulted in several endemic plant species being listed as 'critically endangered'.

The Scrub was gazetted in 1938 as Subject Reserve #1310 for Flora Preservation Purposes "to indicate and protect what the Tolga area of the Atherton Tablelands was once like".

Tolga Scrub, only 26 hectares or 65 acres in area, is long and narrow. It is about 2 kms long and 100 metres wide. This high edge to interior ratio results in significant edge effects such as invasion by feral and domestic animals and weeds. The Scrub is bordered on its longer eastern and western boundaries by a railway line / farmland / industrial estate and the Kennedy Highway respectively; the short northern and southern boundaries by a caravan park and high voltage powerlines. Beantree road separates the northern and southern ends. Some believe this degree of stress will cause the Tolga Scrub to destabilise and deteriorate beyond repair. Our experience has been that the Scrub is changing, for better and worse, but retains an enormous vigour that will ensure its survival. Not only that, it is in the hearts of many Tablelanders, far more so than the more intact fragments of Mabi. It is a landmark through which many drive each day, and it is an island of dense vegetation in the midst of cleared farming land and other development.

What does all this mean for Tolga Bat Hospital?

  • We take an interest in the health of the Tolga Scrub, for its own sake as well as its provision of habitat for flying foxes.
  • The shrub layer makes it very difficult for us to search for fallen bats.
  • Our work at the Tolga Scrub is one more avenue for our group to enter into partnerships with other community groups.

REVEGETATION PROJECTS
We received a grant from the World Wide Fund for Nature (Threatened Species Network) in 2004 for a project "Abating Threats to Spectacled Flying Foxes and their Mabi Habitat". Our partners included the Atherton Shire Council, TREAT, Mareeba Environmental College, Eacham Revegetation Unit, and BRICMA. The aim of the project was to have 2 areas planted on the eastern side of the Tolga Scrub to limit edge effects and improve the integrity of this small fragment of forest. Providing a bushy edge to the Scrub and closing the canopy, limits the effect of weeds and other invasive elements. Eacham Revegetation Unit dug the holes and students from the Mareeba Environmental College planted the trees. The trees had an initial setback as the treeguards we chose were inadequate for predation by pademelons. Stronger treeguards made from wire mesh and fixed to the ground with 3 tent-pegs ensured the safety of the young trees and they have done extremely well. One particularly bare area was fenced before planting, rather than using individual treeguards. All areas within the fence or within treeguards showed good ground cover even at the height of the dry season (see photos below), an indicatio of the level of predation by pademelons and rabbits. During the first dry season we started a watering system using old 20 litre water bottles from the recycling area of the local Waste Station. A small hole was drilled in the base to allow slow drip feed watering. The bottles were filled 3 times over a period of 6 weeks by a water truck. We have continued to maintain these plantings over the years.

   
Fenced area August 04   Tree Guards and watering system Tree planting July 04  

 

 
Fenced area November 06   Same view as above, February 06

Fortunately the WWF-funded planting survived Cyclone Larry in March 2006 as the wind blew from the west. However it did significant damage to the western side of the Scrub, including a large old fig tree that was the centrepiece of a picninc area, and under which we would always get a shady park while working in the Scrub. It was also an important creche tree for the young flying foxes before they could fly out with the colony. After dark, when their mothers had flown out, they would flap and climb their way to this tree and socialise. From here they had some clear space to practice flying without the impediment of canopy.

Tolga Bat Hospital met with the Atherton Shire Council in late 2006 to discuss the repair of this area. A draft landscaping plan is being drawn up by David Leech, and Conservation Volunteers Australia have agreed to help plant the trees.

LAKESIDE SCRUB
Lakeside Scrub is a patch of forest established with the help of TREAT and the old Wet Tropics Tree Planting Scheme in the late 1980s and early 1990s. It is on a piece of land that local government required developers to set aside for environmental purposes. It slopes fairly steeply down to Lake Tinaroo, just outside Yungaburra on the Atherton Tablelands. It is fairly small, 200metres by 100 metres, but despite this, since 2006, has become home to a large maternity colony of Spectacled flying foxes. The bats arrive in September and leave about May/June. A census in December 2009 established the population at about 25000. Tolga Scrub is only about 10 kms away as the bat flies, but since the destructive cyclone Larry in March 2006, the Spectacled flying-foxes (SFF)have camped here in greater numbers than at Tolga. The presence of the SFFs resulted in some community conflict in early 2007, with some residents asking EPA to move the bats.

The Bat Hospital recognised the need for maintenance at Lakeside, not only to gain access for rescue purposes but also to eradicate large amounts of the prickly asparagus fern, seedlings of wild tobacco whose seeds were being brought in by the bats, and coffee. Our partnership with a Green Corps team in 2008 (through Conservation Volunteers Australia and the Tableland Regional Council), allowed this team of young people to help. Another team of young people from the University of New Platz in New York has also helped. Since 2008, Tableland Regional Council has begun a maintenance schedule.

THE BATS
The Tolga Scrub is critical habitat for flying foxes. Spectacled flying foxes are usually at the Tolga Scrub, though the numbers will vary throughout the year, being least in winter. It is a very important maternity camp for them, and is sometimes the only maternity camp on the Tablelands. Census counts in November usually report about 5000 to 10000. The total count for Spectacleds in the Wet Tropics is about 180,000

The Little Red flying foxes (Pteropus scapulatus) are sometimes at Tolga, and often in large numbers compared to the Spectacleds. They rarely use Tolga as a maternity camp, but often arrive when the young are flying, around September. The numbers will sometimes build up by the end of the year to be over a million, but they are usually gone again by March when the wet season sets in. Little Reds can do significant damage to the forest if they hang in the weaker mid-canopy trees. This damage is the result of their characteristic behaviour of hanging in 'bunches' - the branches cannot take the weight and often bend until they break. This damage will repair itself, unlike the damage being done by the cockatoos that results in the death of the tree. However the Little Reds are sometimes camped in large numbers and do no damage, by camping in the larger trees and hanging apart from each other, rather than in bunches. This seems to happen late in the year, just before mating season.

THE COCKATOOS
We work with the Tablelands Regional Council which has trusteeship of the Tolga Scrub. Issues at the moment are weed control and the damage done by sulphur-crested cockatoos. Four consecutive years of heavy winter use in 2000 to 2004 caused the death of 65 tall canopy trees and subsequent closure of the walking track through the Scrub. Council has been granted a permit to use birdfrite as a deterrent to the cockatoos every year since 2003, and this has been quite successful. A condition of their permit from the Environmental Protection Authority is that they notify us when commencing the birdfrite action. The cockatoos camp higher in the trees than the bats and as long as the birdfrite is aimed high, it appears to have little impact on them. Nevertheless we feel it's important that birdfrite is not used until the young are independent of their mothers which happens about March.

TONY IRVINE
Tony was a great friend of the Tolga Scrub until his death in late 2008. He was a superb bushman with an enormous knowledge of native plants, and an advisor to Tablelands Regional Council on the health of the Scrub.

Tolga Bat Hospital - Tolga Scrub 2  

The cockatoos arrive on the Tablelands in large numbers when the peanuts are being harvested, and try to use the Scrub as a camping spot close to the farms. Unfortunately they trim the new growth off the emergent canopy trees, and over 65 such trees died in the early 1990s in the northern area where the flying foxes camp.

Our role is to monitor the effect of the birdfrite on the bats. If the bats are being 'unduly disturbed' then the shooting needs to stop. The noise from the birdfrite appears to have little effect on the bats unless it is fired directly overhead. It has the least effect in the late afternoons, when the bats have 'batnap' for about an hour before flyout. During the 2003 birdfrite trial, the numbers of bats decreased, but in 2004 the numbers increased. So the effect appears to be minimal.

We were partners in installing flying fox signage at the Scrub, at the beginning of the walking track. There are a choice of 4 'hanging signs' below the main permanent sign:

  • No bats at home Flying foxes away on holidays
  • Little Reds have babies Please do not walk through their roost. They willl easily drop their babies if disturbed
  • Little Reds are visiting They disturb very easily,please avoid walking through their roost.
  • Tick paralysis and baby time for Spectacleds Watch for fallen bats
  Tolga Bat Hospital - Bat Sign