Rainforest Restoration Manual for South-Eastern Australia

Bill Peel

• Publisher: CSIRO PUBLISHING
• Year: 2010
• ISBN:
  9780643102040
• Topic: Technik & Maschinenbau
• Subtopic: Nachhaltige Landwirtschaft

Rainforest Restoration Manual for South-Eastern Australia is the definitive guide to the recovery and restoration of Subtropical, Warm Temperate, Cool Temperate, Gallery, Dry, Dry Gully and Littoral Rainforests from south-eastern Queensland toTasmania. All of these rainforest types were inherently rare prior to settlement, and today with depletion, feral animals, weeds and climate change, all are threatened – with many listed under state and federal legislation.

The manual presents detailed restoration methods in 10 easy-to-follow steps, documenting the research and trials undertaken during rainforest restoration over more than two decades. These experiments and their results will empower readers to uncover answers to many of the problems they could encounter. The manual is supported by a CD that provides important background information, with 32 appendices, a propagation manual for the region's 735 rainforest plants, an illustrated glossary and resources for teachers. Species lists and specific planting guides are provided for the 57 rainforest floristic communities that occur from thecoast to the mountains between Durras Mountain in New South Wales and the Otways in Victoria.

Extensively illustrated with colour photographs, this book will empower you or your group to be able to restore, manage, protect and conserve the magnificent rainforests that are in your care. The general principles and techniques described will meet the needs of students and teachers, novices, experienced practitioners, community groups and agencies alike.

CHAPTER 1

Background to rainforest restoration

Take the cows away and this old orchard transforms itself into rainforest

Durras Mountain, Murramarang National Park, New South Wales. Achieving effective rainforest restoration does not necessarily require long and complicated management or large amounts of money or resources. Here the old farmstead orchard – consisting of one walnut tree (yellow foliage), one cherry tree and one apple tree – has attracted fruit-eating species (birds and mammals) that have voided seed from the fruits of rainforest plants growing in the nearby rainforest remnants. The rainforest regeneration illustrated has been facilitated with only two simple changes: the removal of domestic stock grazing and the control of transforming weeds. On this former dairy farm, these relatively cheap and straightforward management actions have released the two ecological brakes that had previously prevented this orchard from returning to rainforest. This is the key to rainforest restoration: applying the minimum amount of effort to get the maximum result. The fruiting rainforest species that have regenerated include: Black Plum Diospyros australis, Red Olive Plum Elaeodendron australe, Rusty Fig Ficus rubiginosa, Climbing Guinea-flower Hibbertia scandens, Muttonwood Myrsine howittiana, Large Mock-olive Notelaea venosa, Small-leaved Bramble Rubus parvifolius and Lilly Pilly Syzygium smithii. Other rainforest species that have colonised beneath the expanding evergreen rainforest canopy include the shade-tolerant species: Bergalia Tussock Carex longebrachiata, Kidney-weed Dichondra repens, Cranesbill Geranium sp., Weeping Grass Microlaena stipoides, Australian Basket-grass Oplismenus hirtellus and Common Tussock-grass Poa labillardierei. The latter observations indicate that once there is a shady evergreen canopy, other shade-dependent species will arrive. This, in turn, illustrates another important component of rainforest restoration: that, with patience, succession will occur and that you – as the rainforest restoration practitioner – are not responsible for returning all of the original biodiversity that was once present on the site. In many ways, it is important that we do not try to complete the picture. There is an ecological, as well as an economic, reason for this advice. The ecological reason for stepping back at some point and letting Nature take her course is that we cannot know every detail of every niche that is available and when it should be filled. We could spend a lot of money and effort trying to discover this, to little advantage, because Nature will put it right when the conditions are the most favourable. The economic reason is self-evident: it would take an enormous amount of time and money to renew every last piece of damaged rainforest in the region. Restoration is about knowing when to act and when not to act. Maximising the effectiveness of our restoration techniques should be our aim, to enable maximum coverage and recovery.

Rainforests of the south-east: small, precious and unique

The rainforests of this region exist as a scattered archipelago of small island-like stands occupying fire-sheltered refuges across an otherwise fire-adapted landscape. They represent the remaining small and precious jewels of a once more widespread and magnificent rainforest estate. The decline in that estate has been going on for millions of years (as a result of continental drift and climate cycles). More recently, there have been cataclysmic changes to both the extent of rainforests and their remaining refuges. They are threatened both by habitat loss and by many more sinister and subtle changes to their habitat, which is being undermined by destructive and all-pervasive factors such as climate change, weeds and pest animals, even in the most remote and virgin bush.

Different but how?

Four things set rainforests apart from all other forests in Australia:

1. They are refugia for taxa that are either ancient (mosses, lichens and ferns) or of Late Cretaceous to Early Tertiary origin. This means that rainforests provide essential habitat to species that cannot live elsewhere and which arose when Australia was still part of Gondwana, flowering plants were just beginning to appear and dinosaurs ruled the Earth.

2. Rainforests are also shadier places than eucalypt forests, with more than 70% of incident light being intercepted by the leaves of the canopy (mature rainforests transmit a mere 4EV of sunlight compared with 16EV for eucalypts; see Chapter S4: Incident light niches (in nature and restoration): Table S8 and Figure S131). With many species not (or only rarely) being found outside these moist, sheltered, verdant and vaulted canopies, their fidelity to this environment is reflected in the many specialised life-forms and species that can cope with low light levels, including vines and bryophytes.

3. Rainforests share their nutrients through very efficient nutrient cycling in the litter layer. This is possible because of the moist microclimate beneath the shady rainforest canopy. Unlike the eucalypt forests – where most nutrients are withdrawn before their leaves are shed (and the frequently dry conditions leads to heavy litter accumulation because of low rates of decomposition) – rainforest plants shed leaves with nutrients still in them, relying on their diverse and abundant soil microbial factories to release nutrients rapidly. The useful nutrients are then taken up again by the plants of the rainforest through their root systems. Rainforests plants therefore have a more ‘socialistic approach’ to sharing plant nutrients, when compared with eucalypt forests. You can test this yourself: how deep is the leaf litter in your local rainforest compared to the next nearest eucalypt forest community? In one example, students investigated this in the Warm Temperate Rainforest of Lake Tyers Forest Park in Victoria, which registered an average 2 cm of leaf litter compared with the adjacent Damp Forest with 15 cm – a relationship replicated across all rainforest EVCs in the region (Additional reading: Leaf litter: rainforest versus non-rainforest communities). The lower ground fuels helps to reduce fire intensity, when and if they do burn. The apparent fertility of rainforests is in reality held in the litter layer and the plants themselves, rather than in the soils per se. This, in part, helps to explain why clearing rainforest for agriculture leads to rapid nutrient loss and site degradation. This occurs because of the rapid oxidation of carbon, which destroys the essential fuel that powers the nutrient cycling machine, and explains why so many agricultural El Dorado’s on volcanic soils have fizzled out as site fertility plummeted soon after the clearing of the rainforests.

4. All rainforests are sensitive to fire. Though most rainforests occur in habitats that have moisture as their main mechanism for avoiding or minimising fire’s impact, others occur in dry and droughty conditions: relying instead on topographic and landscape features to keep fire at bay. This habitat protection is augmented by their shade and lower fuel levels and higher fuel moisture. But there are also other factors at play: in general, rainforest plants have lower volatile oil levels in their leaves and these are less flammable (see Additional reading: Ignition times), their trunks have thin and non-flammable barks and there are usually significant breaks between fuel layers (all of which add up to prevent fuel ladders developing) that could lift a low intensity ground fire into the canopy to become a raging inferno. Most eucalypt forests are exactly the opposite and actually promote fire, with high leaf oil content, flammable litter, bark connected fuels designed to catch and burn into their flammable canopies. Consequently, in most fire events, fire only ‘bites’ into the margins of rainforests while entirely consuming the adjacent eucalypt forests. See also Chapter S7: Fire management at the local scale.

Each of these rainforest features contributes either partially, wholly or in concert to their rarity, conservation significance, threatened status and importance for biodiversity in the Australian landscape today.

Rainforest: from dinosaurs to present day

Rainforests have been around for a long time (around 60 million years), while some rainforest plants, such as the club mosses, have persisted from the time of the first forests on the planet, with the earliest records from Victoria in the Silurian about 400 mya (Richards 2000). Ferns, which are ubiquitous in most rainforests of the region, are also ancient, with the first of the ‘modern’ ferns appearing in the Early Carboniferous 250 mya (Wikipedia).

In the beginning, rainforests were dominated by conifers, but today (in our region) coniferous rainforests are rare (although they still dominate in some of the Cool Temperate Rainforests of Tasmania). In Australia, rainforests are dominated by flowering plants, which began to evolve when Australia was still attached to Antarctica and the other southern landmasses (Africa, South America and India) as a part of the supercontinent Gondwana. Rainforests comprising flowering plants and conifers were present on the (now) Monaro Tableland in the Palaeocene (65–55 mya), with some of the types recognisable today being represented in the Eocene Epoch (55–37 mya) (Peel 1999).

Rainforests arose in cooler, wetter times; and, as the Gondwanan continent began to break up, they have been adapting to the new climates of their Australian continental home as it has moved north for the last 60 million years at the rate of several centimetres per annum (about the same rate that your fingernails grow). Gradually, this brought with it massive changes in climate. Climate change affects organisms in one of three ways: they can stay and adapt; stay and die out; or move. Rainforests and their cargo of organisms have been doing just that and, while they have been adapting and evolving, there have been countless extinctions...

Table of contents

• Cover
• Title
• Copyright
• Dedication
• Contents
• Acknowledgements
• Summary and key findings
• How to use this Manual
• Rainforest restoration updates
• Chapter 1 Background to rainforest restoration
• Chapter 2 Understanding your rainforest and applying first aid
• Chapter 3 Your rainforest and regional context
• Chapter 4 Immediate actions and site planning
• Chapter 5 Choosing the method of restoration
• Chapter 6 Resources
• Chapter 7 Project planning
• Chapter 8 Project implementation
• Chapter 9 What is success in restoration?
• Chapter 10 Maintenance and ongoing ecological management
• Index