Bush regeneration basics for the Illawarra region

An area of bushland heavily infested by Trad (Tradescantia fluminensis), with active control efforts underway. Image by Emma Rooksby. 
Here are some introductory tips on bush regeneration in the Illawarra area. These may be useful if you have some remnant bushland on your property, or if you live near a natural area such as a nature reserve or conservation area.

Using bush regeneration approaches and techniques that have been developed and tested over many years, you can improve the health of local bushland or even expand it, creating more habitat for local fauna.

There is a wealth of information available on bush regeneration, both online and in publications, covering regeneration techniques and ways to individual weed species. This page lists a few key points you should consider before you start work, and provides some further resources.

One of the best sources of knowledge is your local Landcare or Bushcare group, as well as neighbours or other locals with bush regeneration knowledge. Get in touch with your local council, or contact Wollongong City Council Bushcare, Landcare Illawarra or Shoalhaven Landcare for advice and support. Illawarra District Noxious Weeds Authority may also be able to assist.

The context - bush regeneration in the Illawarra region

The physical conditions of the Illawarra - the fertile clay soils, good rainfall and warm, maritime climate across - are quite different from those of the regions further north (Sydney), west of the escarpment cliffline and south (Shoalhaven), which all have sandstone soils and lower rainfall. It is important to take these conditions into account when regenerating local bushland.

The conditions make many of the Illawarra indigenous plants very competitive against weeds, and choosing plants that grow naturally in the area is a vital first step. Unfortunately, the same conditions also favour some key woody weed species that if left unchecked will form strong communities in their own right and may exclude natural native plant regeneration. Few areas across the region are weed-free, and many are significantly degraded.

Some of the key woody weed species in the area include the two Privets (Ligustrum lucidum and L. sinense), African Olive (Olea europaea subsp. cuspidata), Cassia (Senna pendula var. glabrata), Wild Tobacco (Solanum mauritianum) and Camphor Laurel (Cinnamomum camphora). Herbaceous species that are a particular problem in Illawarra include Wild Ginger (Hedychium gardnerianum), which is favoured by moist rainforest conditions and Asparagus Fern (Asparagus aethiopicus) which is widespread in coastal vegetation communities. Climbers such as Madeira Vine (Anredera cordifolia), Cape Ivy (Delairea odorata), Moth Vine (Araujia sericifera), Coastal Morning Glory (Ipomea cairica) and Morning Glory (Ipomoea indica) are also problematic, and Cat’s Claw Creeper (Dolichandra unguis-cati) is also spreading into the area and has already become a well established environmental weed in northern NSW.

As already mentioned though, Illawarra has good soil conditions and a range of vigorous native plants that will compete strongly with introduced weeds if bush regeneration is conscientiously pursued or bush-reconstruction is carried out using revegetation (planting)  of appropriate local native species specific to the vegetation community you are trying to restore.

Things to discover


How healthy is your bushland?

You may be lucky and own or live near a natural area in good condition. Unfortunately, however, much local bushland has been degraded and weeds have outcompeted and replaced many of the native species. Generally speaking, the healthier the bushland, the less work will be involved in regenerating it.

Try and find an area of almost pristine bushland which is of the same vegetation type and aspect as your bushland; this will give you an idea of what species would have been present at your site in the past. Things you can pick up from looking at a good patch of bushland are whether your bushland has a lot of weeds, or has only a few native plant species or has too few trees or no mid- or ground-layer plants.

Signs that your bushland is not so healthy include:
  • Weed invasion, which is a common cause of bushland degradation, and an indicator of poor health. Invasion often starts around the edges of areas of bushland where weeds move in from adjacent verges, gardens or wasteland. in other cases weeds are imported by dumping of garden waste, or weedy seeds are dropped by birds and wind as well as dispersed by vehicles and machinery
  • Overuse or inappropriate use will damage plant communities and the soil they grow in. This can include grazing by deer or wallaby, and human use such as too many walking, car or bike tracks and agriculture
  • Water flows may have changed, for example through stormwater management works, so that water is now directed into your bushland. This can lead to unnaturally high soil fertility, erosion and the importation of silt and weed material.
  • Unnatural fire regimes may negatively affect bushland. Some areas are burnt too often and others not often enough. Fire will alter the species that are present, and can also provide the opportunity for weeds to invade. The native tree species Sweet Pittosporum (Pittosporum undulatum) growing in a woodland community is a common indicator that the fire regime has been altered allowing plants that generally favour wetter sites to regenerate.

Understanding the health of your bushland will help you devise a suitable strategy for restoration.

What do you need to know to start your regeneration work?

Don’t just leap in to change things. You may find that you make the situation worse. A bit of thought and planning is a good way to start.

  • Find out how your bushland might look if it were healthy. What is the type of vegetation – eg is it rainforest, eucalypt forest, woodland, wetland or coastal heath? What is the soil type - sandy, clay, or volcanic?
  • Is your bushland an endangered ecological community (EEC) or does it contain threatened species? If so, you may be able to find some more specific information on how to look after this valuable area from the NSW Office of Environment and Heritage.
  • Try and identify why your bushland is not healthy. See which of the above impacts are affecting the area and work out what you can do to reduce any of these impacts.
  • If there are a lot of weeds in your bushland, find out what species they are and the best way of removing or controlling them. There are many good weed guides out there, including handbooks developed by local councils in the region. Social media can help with plant identification and various groups and pages have members that are more than willing to assist with identification of any plants you may have growing on sites. Always be sure to check that plants identified using this method are checked by using plant identification books and websites such as PlantNET.
  • Look at what function weeds and other impacts are performing. Weeds are sometimes used by native fauna as habitat; weed-covered silted areas along a creek may be slowing the water follow and so minimising erosion. Although the broader aim is to have healthy native vegetation, you may need to think about how to replace such functions when they are currently performed by weeds. Healthy habitat might need to be created elsewhere in the interim; you might leave your weedy silted area until you can put in some other mechanism to slow water flow. As a general rule try not to overclear areas as this may lead to an influx of weeds that were not previously present or make the follow-up maintenance a daunting task.
  • Use the ‘And then what?’ method of planning your work. Whatever you do will have an effect and if you can think about this, you may plan your work a bit differently.
  • Keep in mind that once a plant is removed from a particular area, something else will always grow in its place. If your site has good resilience (ability to regenerate with native species) you may find native plants will take the place of weeds quickly and easily. Sites with lower resilience may require planting to assist natural regeneration by providing a seed source for future plant succession.


Some principles to guide you

When planning what to do, consider the following general principles:
  1. Retain first: keep your natural bushland, particularly the highest-quality areas, and take steps to minimise the impacts which may degrade it. Retaining the native diversity present on a site is crucial as this is where the seed source for successive regeneration will come from in the future.
  2. Regenerate second: aim to maximise the ability of bushland on your property to regenerate naturally, and continue to treat impacts such as minor weed incursions within the high-quality bushland area. This might require continued monitoring of weed growth and removal of weeds that return within the good areas to assist native plant succession.
  3. Replant last: Sometimes past impacts in certain areas are too great and the site has lost its resilience (ability to regenerate naturally). In these cases planting local native species can reinstate the biodiversity and fauna habitat of the site. Planting canopy species within a site will also help to exclude weeds that favour full sun and minimise the need to remove annual weeds that have a short life cycle and produce an abundance of seeds.  Ensure you use only local native species that would have occurred naturally within that particular vegetation community and obtain plants of local provenance (grown from locally sourced seed) where possible, not from seed sourced from another part of the state.
  4. Seek professional advice: The principles above are a general guide only and seeking professional advice from local botanists and bush regeneration experts will allow you to best support recovery of your local site. Bush regeneration experts can advise on prioritising weeds to remove and what approach to take overall. Botanists can help with more complex tasks such as conducting population age and class assessments for the species present on the site, checking other nearby sites to work out the original species mix, and evaluating whether any inbreeding is occurring.
It is important to work out how big an area to treat, so that you will be able to keep the area in good condition. If weed growth is the major degrading impact, your first weed removal work needs to be at a pace so that you will have the time remove the subsequent flushes of weed growth and so maintain the area weed-free.

Some good hints are:
  • Always start from the good (less weedy) areas and work outwards from there toward the weedier areas as time and resources permit. This allows you to retain the natural diversity on site and have minimal follow-up weed removal requirements.
  • Allow the health of treated sites to dictate how quickly you progress into less healthy areas.
  • Try to minimise over-clearing which can make follow-up weeding a daunting task.

Determining the species suitable for your regeneration site

The indigenous plants already growing on your site are typically among the species that occur their naturally, but some species may be missing due to degradation of the site over time. Species suitable for a given site can be determined by inference from nearby sites, either by observing what is growing nearby or by referring to the Illawarra Bushland Database which contains species lists for over 100 sites across the region.

Plant profiles on this website's database describe the habitats that each plant species prefers. You can search the database for plants that occur in a number of different zones. The whole area is divided into:
  • Coastline strip, which includes sandy seaside areas; seacliff areas such as Bombo Headland; hind dunes; and swampy saltmarsh sites.
  • Wetland areas including estuaries, lagoons and freshwater streams and lakes that lie between the coastline strip and coastal plain.
  • Coastal plain including outlying hills (e.g. at Blackbutt Reserve, Moeyan Hill Reserve, Mangerton Park); floodplains like Broughton Creek; floodplain swamp and other floodplain areas such as at West Dapto.
  • Riparian areas associated with creeks, which are mostly completely cleared or appear as degraded weedy communities
  • Escarpment, which is divided into lower escarpment (including the foothills) and upper escarpment (areas of warm temperate rainforest).
  • Volcanic, which covers areas with soils derived from igneous rocks (e.g. Berkeley Hills, Kiama and Saddleback Mountain, and the escarpment from Foxground to Cambewarra Mountain).


For more detailed information on these zones, see About the region. There are a few areas that are characteristically different from the overall vegetation patterns of the district that may also be referred to in the descriptions of individual plant species. These include Croom, West Dapto, Curry’s Mountain, Stockyard Mountain and Broker's Nose.

Historical records and photographs can also be useful resources to determine what plants grew on a particular site in the past. The Wollongong Spyglass is one useful tool to determine whether your site contains remnant vegetation or if the bushland existing on site is re-growth within the last 50 or so years. If your site is within a creek line, have a look at the top of the catchment. This can sometimes give a good indication of what the vegetation was once like within the site you are trying to restore and can also help to dictate what plants you choose if revegetating your site is the best method within that particular area.

Resources

There is a lot of information to help you on your way. Here are just a few of the most useful resources:
Notes prepared by Louise Brodie, with input from Leon Fuller, Carl Glaister and Marcus Burgess.

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