Most revegetation programs consist of an initial investment in planting seedlings, followed by at most a few years of management to confirm that most of the plants establish. Success is often measured as the number of plants that initially survive. This does not secure habitat that benefits wildlife.
Bio·R believes ongoing investment is needed to maintain the initial plantings and effectively manage them into the future. This involves tracking the success of plantings, recording habitat quality, controlling weeds and monitoring the effects of grazing herbivores.
By monitoring outcomes we can also adjust our on-ground works to deliver continual improvements in the habitats we create, developing world-class techniques for habitat reconstruction.
One of the greatest challenges to habitat reconstruction – apart from keeping seedlings alive in southern Australia with the increasingly harsh summers in a changing climate – is the impact of introduced and overabundant native herbivores.
The seedlings planted and sown at our planting festivals at Frahns Farm, Monarto, need care to successfully establish them beyond their first summer. The thousands of hours our team and volunteers spend preparing soil and growing, planting and watering these seedlings can all be wasted if they are grazed to the ground.
Like many woodland areas in south-eastern Australia, overgrazing by kangaroos in particular causes damage to plants and is a pressing issue at Frahns Farm. To determine the extent of this issue we ran experiments where we left 25% of 250 test seedlings unguarded after planting. All were consumed and removed within 2 months. But guarding every seedling that is planted is expensive, laborious and, to an extent, restricts the plant’s growth in its first few years. Fencing large areas of land to exclude unwanted herbivores is more efficient and cost-effective, as was found at Cygnet Park Sanctuary, Kangaroo Island.
In 2018, funding from the Klein Family Foundation and the Federal Government’s National Landcare Program enabled Bio·R to construct a 5-km kangaroo-proof fence around 167 hectares of Frahns Farm and remove the kangaroos. Not only does this fence now prevent any newly reconstructed habitat from being grazed by kangaroos, but it also protects the small patches of remnant native vegetation, allowing remnant plants to resprout and recruit.
To monitor the benefits of this fencing, Bio·R has established permanent vegetation transects inside and outside the fenced area, where key plant species are identified, measured and mapped at regular intervals. By noting how the leaves and branches have been chomped, we can also assess the level of damage done by these hungry herbivores. We will continue to survey these transects into the future to see how the plants inside the fenced area recover and inform the best ways to manage herbivores in future plantings.
Bio·R monitors the survival and health of the many thousands of seedlings we plant annually, noting planting densities, aspect, vigour and susceptibility to heat waves. This gives us detailed information on which species grow most successfully and which species might need extra help to establish.
We also use the Native Vegetation Council’s Bushland Assessment Method to track the health of the habitat we have established as it grows. Having a repeatable way to track the trajectory of the plant communities we have reconstructed allows us to judge the success of our revegetation techniques, and continually improve them as we learn more.
Restoration of the landscape is a key part of improving habitat for our woodland birds. One of Bio·R’s biggest challenges is that in the Mount Lofty Ranges, the amount of land needed for the survival of all our birds is three times the current area of native and restored vegetation. That much land is hard to come by quickly. So what can we do in the short term?
Any land that becomes available for revegetation should be planted out to provide the maximum ecological benefit for our wildlife. For honeyeaters, this means giving them a year-round supply of nectar. There are always some South Australian Blue Gum (Eucalyptus leucoxylon) trees flowering at all times of the year in the Mount Lofty Ranges but never in the one location. It is unclear whether these flowering patterns are caused by local environmental factors or genes.
At Frahns Farm, Monarto, we have established an experiment to test if seeds collected from a population that flowers at a known time but planted in a completely different area will flower true to their source population once mature, rather than just flower in response to local environmental conditions. If they do, we can establish trees of different provenances and create revegetation that provides resources for nectar-lovers throughout the year, providing another planning tool to ensure future reconstructed habitats are as productive for our fauna as possible.
Plant monitoring surveys are the perfect introduction to fieldwork. If you’re looking to improve your flora identification skills or develop your ecological expertise sign up to be notified of the next volunteer opportunities on these projects.
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