Ways to improve natural assets on a farm Protecting patches of remnant vegetation

The woodlands of south-eastern Australia

The woodlands that once characterised south-eastern Australia were significantly reduced in extent by land clearing over the past two hundred years. 85% of the original woodland cover inland of the Great Dividing Range, from southern Queensland, through NSW, Victoria and eastern South Australia, has been cleared.

Box-gum grassy woodlands, the major woodland type in the Sustainable Farms project area, have been similarly cleared and fragmented. The patches of remnant woodland that remain are often located on farms, or adjacent to farms as part of Travelling Stock Routes or roadside vegetation.

Woodlands are distinguished from forests by the open nature of their canopy and the wide spacing between trees. Healthy box-gum grassy woodlands are typically highly diverse, both in terms of vegetation structure (a mix of overstorey and understory) and species diversity.

Patches of remnant woodland are important natural assets for farms. They can provide shelter for livestock, havens for predatory insects that help control pest species, and refuges for pollinators of crops such as canola. They are also key habitats for a wide range of native animals and plants.

Remnant woodlands and biodiversity

Remnant woodland patches are often the most biodiverse places on a farm. They have generally experienced less disturbance, enabling native plants such as forbs, grasses and shrubs to persist. Remnant patches will often contain trees of mixed ages, and habitat features such as fallen logs, dead trees and tree hollows. The combination of these features make remnant woodland patches vital for biodiversity, particularly for rare and threatened plant and animal species.

Large remnants are typically the most valuable for supporting biodiversity, but small remnants – even a single isolated paddock tree – are also incredibly important. How a remnant patch is managed will play a role too – a small, well-managed patch of remnant vegetation may support a range of species of plants and animals.

The role of remnant vegetation in supporting farm productivity

Agricultural productivity relies on healthy, well-functioning ecosystems and the ecosystem services that these provide. In largely cleared landscapes, the patches of vegetation that remain take on a disproportionate significance. While the loss of one small patch might not seem important, at a landscape scale the cumulative loss of vegetation can have a serious impact.

The presence of native vegetation on farms is important for a range of reasons, including:

• Carbon storage
• Stabilising soils and contributing to water infiltration
• Managing water tables and reducing the risk of secondary salinity affecting agricultural land
• Providing habitat and resources for pollinating insects
• Provide shelter and shade for stock
• Act as windbreaks, reducing evaporation and desiccation
• Support biodiversity that provide ecosystem services.

Ways to manage remnant vegetation on a farm

While new plantings, shelterbelts and regrowth woodland are important environments on farms, they represent a different type of vegetation assets on a farm when compared to remnant vegetation. Even if your farm has recent plantings, or you’re planning to plant shelterbelts, it is vital to retain remnant old trees and woodland. Managing these areas carefully can help enhance the vegetation structure and diversity, and contribute to broader landscape function and farm productivity.

Management actions for remnant patches

Limit grazing pressure, particularly by fencing to control livestock access, but also by controlling exotic herbivores such as rabbits and overabundant native animals such as kangaroos.

Allow natural regeneration of overstorey and understorey plants to occur.

Keep fallen timber. Resist the temptation to remove fallen timber and logs – these provide habitat and food resources for a range of native animals. Fallen timber can also provide refuge for wildlife during fire. If fallen timber does need to be removed for safety or access considerations, move it to patches of bush or new plantings where it can add value as habitat and to help control erosion.

Keep large dead trees as they provide nesting and denning sites for many native animals, including sugar gliders, squirrel gliders, feathertail gliders, laughing kookaburras and superb parrots. Suitable nesting hollows can take more than a century to develop in most species of eucalypts.

Avoid clearing or burning dead trees or fallen timber. While fire is a natural part of woodlands ecology, even cool fires can destroy important habitats that take hundreds of years to develop. Note that while dead trees and fallen timber will burn, they are “heavy fuels” which are slow to ignite and are not a major factor in high fire risk.

Leave mistletoe. It is a valuable food source for native animals and usually does not have significant adverse effects on host trees.

Use wildlife-friendly fencing around remnant patches. Given the likelihood that marsupial gliders will utilise vegetation patches, consider using electric fencing or replacing barbed wire with plain wire on the top strand of fences in key glideways. Alternatively, cover the top barbed strand with polypipe. This will reduce the chance of gliders and other animals becoming tangled and dying.