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Bio·R Newsletter | December 2019

Director’s Letter

There is a song written by Paul Seeger in the 1950s “Where have all the flowers gone, long-time ago? …When will they ever learn?”. The song is about the atrocities of war and has been recorded by many artists and in many languages ever since. The first version I recall hearing was by Peter, Paul and Mary (PPM) in the mid-1960s and I had largely forgotten the words and tune until the mid-1990s, some 30 years later. My PPM moment (as I refer to it) happened when I returned to Sandy Creek Conservation Park. In the 1970s and early 1980s this park was alive with birds particularly in winter, when about a dozen species of honeyeaters and silvereyes feasted on the nectar provided by the abundant understorey shrub, Flame Heath. But by the mid- to late-1990s the understorey was a shadow of itself, and both honeyeaters and Flame Heath were few and far between. I thought, where have all the flowers gone? The prophetic words of Seeger’s song came flooding back and have stayed with me ever since.

Anyone familiar with Flame Heath knows it is a prickly plant, but the plants that remained in Sandy Creek had been heavily grazed to the point of being bonsaied. A few years later those plants were dead. The culprits were Western Grey Kangaroos, which eat the fresh shoots before they become prickly. Their numbers had been steadily increasing whilst we lost plants, flowers and birds. In 2002 a series of fenced plots were established in some of the worst areas to exclude the kangaroos. Both inside and outside the plots, seedlings of Flame Heath, Silver Banksia and other plants appeared. However, these seedlings vanished from the outside, but inside most survived and within 10 years the heathy understorey that I remembered had been re-established, albeit only inside the small fenced “exclosures”.

Inspection of other reserves supporting woodland and heathland habitats showed that these too were also being severely overgrazed by kangaroos, and similar exclusion plots have been installed in these other reserves and have shown how widespread and destructive the overgrazing has been for many understory plant species and their associated fauna, both vertebrate and invertebrate. Species of Acrotriche, Leptospermum, Allocasuarina, Acacia, Hibbertia, peas, orchids and a suite of grasses are all doing much better inside these exclosures. Again these exclosures are small in scale and are largely addressing the symptom rather than the underlying cause which is the overabundance of kangaroos; they are not a solution. Last year Bio-R erected a kangaroo exclusion fence around a 135 ha of Frahns Farm to eliminate the grazing pressure exerted by macropods. This not only protects the seedlings that we have planted, but also allows a range of plants including Lomandra, Allocasuarina and Bursaria to recover – and the signs of recovery are obvious already.

A combination of factors have led to the overabundance of kangaroos in the Mount Lofty region. The most important is the provision of extensive areas of pasture grasses that provide kangaroos with the bulk of their food but, by day, kangaroos shelter in the few areas of native vegetation that remain and browse native plants there. Other factors that have likely helped kangaroo populations grow are the removal of dingos, a key predator from the region, and the provision of water. Ultimately the abundances of kangaroos need to be reduced substantially if the biodiversity of the region is to be sustained. There is a lesson here and that is that we need to manage our remnant flora and fauna in a proactive manner. Sadly, we continue to allocate too little time and resources to do this, and we continually duck the hard management decisions because of concerns of public backlash. When will we ever learn?

David C Paton AM
Director, Bio·R

DIRECTORS LETTER DCP 1


What Whistler’s Want: A Reveg Perspective – Tom Hunt

What’s the best way to restore habitat for wildlife? Most revegetation programs aim to replicate the plant community that grew in an area before clearance, but even the most diverse planting regimes struggle to approach the productivity and complexity of untouched native habitat. Intricate schemes also more expensive which, given the scarcity of the conservation dollar, can be restrictive.

More importantly, does this approach provide the greatest benefits for declining wildlife? Evidence suggests that while common species benefit from most plantings, rarer species usually have more specific habitat requirements and miss out. Amid the current biodiversity crisis into which the world’s wildlife is currently sinking, and the funding shortfall to properly address it, perhaps it’s time to flip our approach to revegetation on its head.

It may not appease the fundamentalist botanist, but, rather than trying to restore our guess at a pre-colonial plant community, it seems pragmatic to tackle habitat restoration from the perspective of those plant and animal species we’re aiming to conserve.

Research I undertook on Rufous Whistlers, a woodland bird found across South Australia’s Mount Lofty Ranges, illustrates a case as to why this approach may be more effective at delivering successful conservation outcomes. This study was based in the Monarto area where almost 1800 hectares of trees and shrubs were planted alongside patches of remnant eucalypt woodland in the 1970s, originally to beautify the area for a satellite city that never eventuated. The revegetation, known as the Monarto Woodlands, is now one of the largest areas of habitat in the region, but unlike most habitat plantings it was never created for biodiversity or restoration purposes and contains an odd mix of local, interstate and exotic plant species, though with dozens of species, diversity is high.

Calling this area home was my study species, the melodious and jaunty Rufous Whistler, which – along with a suite of other woodland birds in south-eastern Australia – is sadly undergoing significant declines due to habitat loss. I was particularly interested in how the whistlers used the remnant habitat versus the revegetation to see what we could learn about the requirements of these birds and how this can be incorporated to make future plantings more effective for their conservation.

Rufous Whistlers defend distinct territories throughout their summer breeding season, and after attaching tiny radio-trackers to seven birds, I followed them for several weeks from dawn to dusk to record their behaviour and determine the extent of their territories in different vegetation types.

The maps below show the areas several individual birds occupied over the study in areas across both remnant and revegetation. For ‘Whistler A’, requirements were met entirely in revegetated habitat, which is a good indication that these plantings can provide everything a Rufous Whistler needs. But what surprised me the most was that ‘Whistler B’ occupied mainly remnant woodland and was recorded over a 132 hectare area, an order of magnitude greater than the 5.3 hectares used by the Whistler A.

Habitat that is full of food and other resources will mean a bird won’t need to move far to fulfil its daily energy requirements, so a small home range size can be interpreted to represent a highly productive area; by this metric the revegetation appears to be much better habitat than the remnant. But why?

One explanation may be that over 20 different planted trees and shrubs were growing in Whistler A’s territory, compared with the 6 dominant natives found in the remnant habitat that Whistler B used. Rufous Whistlers like to forage for invertebrates in dense foliage from the ground to the canopy, so having a structurally diverse habitat that supports more prey items suits them well.

The revegetation was also established on the deeper soils of old farmland, whereas the remnant only persists on rocky slopes, so the underlying productivity of the soil may drive home range size by improving vegetation growth and therefore the resources available higher in the food web. It’s a reminder that in the Mount Lofty Ranges, disproportional clearance of fertile areas means that the 9% of vegetation remaining is mostly growing on shallow, poor soils that are unsuitable for agriculture, but also not ideal for wildlife (being the main cause of species declines in the region). This is not to say that revegetation is intrinsically preferable, but the remnant vegetation we have left may not provide the best blueprint on which to base habitat reconstruction.

The unusual mix of plants in the Monarto Woodlands, and the fact they were planted on reclaimed good-quality land, has inadvertently created a fantastic habitat for birds: an impressive 92 species have been recorded there, 40 of which – like the Rufous Whistler – are declining.

The introduced pines, peppercorns and Western Australian eucalypts of these plantings aren’t the key per se, but if we are serious about stopping wildlife disappearing, we may need to let go of the idea of restoring landscapes exactly to what we think their pre-colonial state was, and instead focus on innovative techniques to create novel, high-diversity habitats on good quality land. Establishing a novel range of plants to provide year-round resources (e.g. a mix of spring, summer and autumn flowering eucalypt species from the broader landscape) and an increased diversity of structures may mean the resulting habitat can support many more species of animal. This way, we can create habitats with the greatest productivity, function, and long-term value for the threatened species we are targeting.

There may be other benefits, too, such as an increased resilience of the habitat to climate change. With a more diverse combination of plant species with a variety of survival techniques, you improve the robustness and adaptability of your habitat in the face of a future where environmental conditions may change drastically.

An animal-centric approach to revegetation is unconventional, but promising. However, there are many things we still don’t know, especially what features of a habitat a species actually needs, so much more research is needed. Still, given our limited conservation resources, it might just be difference needed to create habitat that can support sustainable populations of our declining wildlife and save them from disappearing. If we know we can plant revegetation that supports 10 pairs of Rufous Whistlers instead of just one, why wouldn’t we?


Seedlings Thriving at Frahns Farm – Penny Paton

If you are reading this, there is a good chance that you were one of the 260 people who helped BioR put in 5,300 plants of 62 species at Frahns Farm inside the new kangaroo proof enclosure on 23rd June 2019. We had a magnificent day for planting and were overwhelmed by the support, camaraderie and wonderful sense of community engendered by the event.

Photo 3 SA blue gum FF rev 2019
A South Australian Blue Gum growing well in the Frahns Farm 2019 plantings.

But the growing and planting are only the beginning of the journey towards success in restoration. Previous years plantings showed us that watering of tubestock in the hotter drier months is essential at Frahns, where conditions over summer are difficult for newly planted tubestock. So, thanks to John Morley and his helpers, a system of black poly piping was installed along the scalped rows, which allowed us to access water from the SA Water pipeline via hoses that plugged in at intervals along the rows. 

Beginning in October, an intrepid band of waterers spent one or two days per month watering our precious plants, assisted by excellent rains at the end of January and start of February and through April. We also watered the many rows of native grasses which had germinated well in the spring (Photo 1 – direct seeded grasses in scalped rows). These direct seeded grasses flowered and set seed over spring and summer and hopefully will lead to many generations of native grasses over the site.

Photo 2 gen view reveg 2019
General view of scalped row

Although no actual counts of surviving plants were made, we estimated that about 85% of plants put in the ground in June survived through to March, by which time there was enough rainfall not to need to water again. There did not seem to be any pattern in terms of plant species that survived or otherwise, but the general feeling was that the plants at the top of the hill had fared worse than those lower down the slope. Also plants put in amongst the trees along the edges of the scalped plot, which had to deal with greater competition from native plants and weeds, had fared worse than those in the scalped rows (Photo 2 – general view of scalped row).  Regular watering as well as scalping of the topsoil to lessen weed competition has led to very healthy plants, some of which have flowered in their first year.

Thanks to all the people who came out and ensured the great survival of plants, and particularly to those who helped on multiple occasions – John, Loraine, Garry, Betty, Keith and Jan. We also acknowledge the Klein Family Foundation whose very generous donation made this project possible. 


Mallee Emu-wren Fundraising Pin

Illustrator and creative extraordinaire Jesses Mess will donate $500 to BioR when she sells 100 of her delightful Mallee Emu-wren pins.

Why not help her (and us!) reach that goal?

Simply follow the link to her Etsy store to sport one of these speccy pins and save our wildlife whilst you’re at it!

https://www.etsy.com/shop/jessesmess

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