Four part blog series ghost written for Ecological Consultants Australia
PART 1: WHAT LIVES IN OUR TREES?
Trees are vital habitats for Australia’s wildlife, providing areas to nest, seek refuge, breed and forage. Tree work done by Arborist’s is crucial for keeping trees healthy, but it is equally as important to protect local wildlife to maintain the health of the environment. Each animal plays an important part in the ecosystem such as keeping pest populations under control and assisting with plant fertilisation by dispersing seeds.
Animals that live in bush close to urban areas are already threatened by predation from domestic pets, road accidents and habitat loss, so it is important for arborists to take care to minimise disturbance to wildlife while undertaking tree works. The first step in doing so is to understand what lives in our trees and where.
Many animals use different parts of a tree for a variety of reasons. Ground mammals such as Bandicoots, Quolls, Antechinus and native rodents can be found in tree roots, leaf litter and fallen logs where they take refuge, nest or forage for food. Repltiles also use leaf litter as breeding areas.
Loose bark on the tree trunk is used by microbats and reptiles for roosting, refuge and breeding; birds forage for insects living under loose bark and native bees use loose bark for hive development.
Tree hollows found on the trunk and on large branches are used by birds, bats and arboreal mammals (tree dwellers) such as Squirrel Gliders and possums for nesting, roosting and refuge although these mammals can also be found in dead trees on the ground.
The canopy, which is where the majority of pruning takes place, is used by birds for nesting; by fruit bats for roosting and a variety of animals such as microbats, Koalas, possums and Squirrel gliders for foraging.
All parts of a tree are important to a variety of animals. In order for arboritsts to work in an animal friendly way, a basic understanding of what animals to expect in different parts of a tree is important. From here, arborists can identify what animals they could disturb while undertaking works and what animals will need alternate habitats if pruning or tree removal is taking place. Once identified, alternate habitats such as nest boxes should be created to replace those that will be removed or disturbed. More on this topic in part 2.
For more information, see Dragonfly Environmental’s Minimal Guidelines for Wildlife Care and their Habitats during works. Dragonfly Environmental and Ecological Consultants Australia provides training for arborists as well as ecological assessments and wildlife recommendations
PART 2 – PROVIDING ALTERNATE HABITAT
In the previous post, we explained how animals use different parts of a tree. With this knowledge, arborists should be able to identify areas within their work site that might be used by wildlife. This is an important step that should take place during site inductions and pre-work meetings.
Obvious tree hollows, loose bark, dead trees and logs should be investigated before works. Even if they are empty, check for feathers, eggs or bones which may indicate that they are still active. It is also important to note that some animals such as Squirrel Gliders Iive in large family groups so if one is spotted, there is likely to be many.
Once animal use areas have been identified, re-evaluate plans and asses whether parts of the tree that are being used by wildlife need to be pruned. To minimise the disturbance try to prune or cut branches above tree hollows and loose bark; choose branches without tree hollows for removal or consider not removing dead branches or branches with lots of loose bark.
If this is not possible, alternate habitats such as nest boxes should be installed and enough time should be allowed time for the animals to relocate.
There are a number of different options for creating alternate habitats for displaced animals.
Native Bees: Native bees live in tree hollows – replacing hollows and providing habitat such as this for other native bee species assists in keeping populations sustainable.
Nest Boxes: Nest boxes come in a variety of sizes and shapes depending on the species that they are intended for use. Generally, larger nest boxes are used by large tree dwelling (arboreal) mammals and owls; medium-sized nest boxes are used by large parrots and gliders; and smaller nest boxes are used by smaller parrots and reptiles. Micro-bats prefer nest boxes with slit openings at the bottom for them to climb into, whereas other wildlife will enter the hole at the front.
Nest boxes should be placed at least 3m high away from disturbance and protected from direct sunlight and prevailing winds. Different species have different requirements so check with a fauna expert if you’re unsure.
Old hollows and logs: Hollows and stumps that have been removed due to tree works are ideal for re-usage if attached and placed correctly. They are also cheaper. Old hollows can be fitted to a tree and should be placed similarly to nest boxes. Old hollows and logs can also be placed in suitable, vegetated areas on the ground.
Old jeans: These are great for micro-bats and reptiles that would normally roost under tree bark. They can be easily nailed to a tree.
Re-planting: Tree species that have been removed can be replaced by planting tube stock of the same species in areas more suitable. This is especially important when working with endangered species and communities.
After identifying active wildlife habitat in a site, alternate homes should be installed for wildlife to relocate to. Working with environmental specialists such as Dragonfly Environmental or Ecological Consultants Australia will ensure the most effective alternate habitats are used.
For more information on Wildlife Friendly Tree Works see Dragonfly Environmental’s ‘Minimal Guidelines for Wildlife Care and their Habitats during works’ document and look out for our next post on how to relocate animals.
PART 3: RELOCATING WILDLIFE PRIOR TO WORKS
In previous posts, we explained how to identify wildlife habitats on a site and how to create alternate habitats such as nest boxes for displaced animals. It is very important to have alternate habitat sites ready well before works take place in order to give wildlife enough time to relocate.
Before attempting to relocate wildlife, it is highly recommended that you arrange for an animal rescuer to be on site so that they can tend to the animals in the most appropriate manner. Dragonfly Environmental and Ecological Consultants Australia provide these services. Stress can be extremely detrimental to an animals wellbeing and can even cause death. At the very least, you should be equipped with blankets, containers with lids, water and the contact number for your local vet in case you need to tend to injured wildlife.
The most commonly recommended method of encouraging wildlife to relocate on their own is by tree tapping, however success rates tend to be low because the animals are afraid that if they leave, they will be eaten.
Most Australian animals are nocturnal which means that they are likely to remain in their refuge areas if they are disturbed during the day. For this reason, it is best to relocate animals at dusk or dawn as animals are more likely to flee if disturbed.
To maximise results, disturb the tree by loudly tapping tree hollows, roots and any other usage areas identified at prior visits which will encourage the wildlife to move away. Don’t forget to create disturbance on the ground where you will be working, particularly where branches will fall to ensure ground dwellers are cleared. The areas should be tapped loudly for at least 10 minutes.
This should be done at least one day before tree works to allow enough time for the animals to relocate to alternate habitats and repeated immediately before tree works begin to ensure no new animals have inhabited recently vacated areas.
Once you’ve finished disturbing the habitats, be sure to stay on the site to ensure that fleeing wildlife safely relocates to the new habitats. If they don’t, a wildlife rescuer should be on-hand to rescue them. If a wildlife rescuer is not on site, use a blanket to capture the animal. A carry container with a lid should be kept on-hand with blankets and water. The blanket should cover the basket to minimise stress to the animal. The animal should then be released in a safe environment or if injured, either a local wildlife rescue centre should be contacted or the animal be taken to a local vet for treatment.
Remember, the best way to safely relocate wildlife is by having professionals on hand. Dragonfly Environmental and Ecological Consultants Australia can provide these services as well as wildlife training for arborists to ensure that wildlife is taken care of prior to tree works. It is also important to be aware of wildlife during and after tree works as this is the time where the animals will be most stressed. Look out for our next post for tips on wildlife safety during and after works.
For more information on Wildlife Friendly Tree Works see Dragonfly Environmental’s Minimal Guidelines for Wildlife Care and their Habitats during works document.
PART 4: CARING FOR WILDLIFE DURING AND AFTER WORKS
Previous posts explain wildlife friendly pre-works tips such as understanding wildlife and how to safely relocate animals to alternate habitats. However, the reality is that no matter how much you prepare, there is still a chance that you’ll encounter wildlife while doing tree works, and as this is the time when animals will be most stressed, knowing what to do is extremely important.
As with relocation efforts prior to works, it is important for a wildlife professional to be on site to ensure the most appropriate care is given to any animals that need it. Also be sure to have the appropriate materials such blankets, containers with lids and water on site during works. This is critical as it is the time that animals are most likely to be encountered.
The noise of tree works is a major disruption for wildlife and it is likely that any remaining wildlife will flee while works are being conducted. If you see wildlife escape, stop working to observe the animals and ensure they reach a safe place. This is particularly important for sites that are situated near roads or urban areas that pose various threats to wildlife. If an animal heads toward roads or houses, catch it with a blanket and place it into a container with a lid and call a wildlife rescuer or vet if there isn’t one on site.
Be sure to check cut branches for wildlife before putting them in the chipper to ensure that no animals are hurt. Often the first sign of an animal is when a hollow is placed in the chipper as they will flee the noise and vibration. Also remember that Sugar Gliders, Squirrel Gliders and other animals live in large family groups, so if you see one in a cut branch, look out for others as there are likely to be more.
If hollowed branches were pruned, it is better to leave them on site or reinstall them in nearby areas as alternate habitat. You can also connect councils or environmental works groups such as Dragonfly Environmental who often seek hollow logs for use in environmental enhancement works.
Once tree works are complete, it is important to continue to monitor and care for the site to minimise the impact of tree work disturbance. If animals were released, they should be observed to ensure they are safety and healthy. Nest Boxes and tree hollows should also be monitored to confirm that they were correctly installed.
Replanting after works will also help to maintain a healthy environment and ensure that there will be plenty of habitat for wildlife in the future. Plant trees often so that when the old ones have to come out there are sufficient young ones already coming up to mature size. Also plant a variety of locally native plants. Vegetation is the supermarket for native animals and variety is the answer to ensuring there are things flowering year round. Contact bush regeneration companies such as Dragonfly Environmental to assist with environmental restoration works.
Dragonfly Environmental and Ecological Consultants Australia also provide training for arborists, which is a great way to gain valuable knowledge on how to conduct wildlife friendly tree works.
Trees and the wildlife that inhabit them are important for a healthy environment and although tree works are necessary, the protection and maintenance of wildlife and their habitats is essential. For more information, see the Minimal Guidelines for Wildlife Care and their Habitats during works document by Dragonfly Environmental.
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