Cutting edge technology using Adenanthos for landscape restoration

For the first time at a large scale within southwest Australia’s Gondwana Link, we have used cuttings of key ecological species for landscape restoration. Glen Steven, Barry Heydenrych and Geoff Woodall explain how.

While seed can be easily collected from most native species, collecting seed from some key functional species (those which perform important ecological services such as providing nectar over a long period or dense cover for fauna) may be difficult and often not cost effective. An example is Adenanthos cuneatus, an ecologically important species which has not been used in large scale revegetation to date.

A. cuneatus, also known as Coastal Jug Flower, is a spreading shrub in the proteaceae family. It is a key functional species as the flowers, which are borne over a long period of the year, provide nectar over an extended period. It is an important food source for a number of animals, including Honey Possums, Silvereyes, Honeyeaters and particularly the Western Spinebill (Acanthorhynchus superciliosus).

Sandplain (Kwongan) ecosystems can have a high vegetation cover of Adenanthos and this species forms a key structural element in these ecosystems. Spreading and dense Adenanthos bushes are long lived and provide habitat for many native animals. These characteristics also play a key role in preventing the establishment and proliferation of perennial grass weeds such as Veldt Grass and Love Grass.

Identifying the problem

Geoff first noted the absence of this species in revegetation projects between the Porongurups, Stirling Range and Fitzgerald River in 2012. During that year he was asked by a conservation group to revegetate an area where previous revegetation attempts had failed.

It was clear during a site assessment that direct sowing natives with improved agronomic approaches would not alone deliver the result that the conservation group were after – Adenanthos cuneatus was absent from the proposed seed and seedling lists. Adenanthos cuneatus was a major player at this site – providing up to 50% of the vegetation cover – but there was no cost effective way that we were able to collect seed from it.

Finding a solution

With no cost effective way to collect seed, we decided to harvest cutting material from 10 wild plants growing in the South Stirlings and cuttings were struck at the Department of Agriculture’s propagation facilities in Albany. Cuttings from eight of the ten mother plants struck, though the strike rate was better from some individual plants than others.  The trial showed that the production of rooted cuttings, with a broad genetic base, could be produced for potential use in restoration.

Aren’t Adenanthos cuttings already used?

Although this species has not been used in broad scale revegetation projects in the Gondwana Link area, the species is commonly used in recreational and ornamental horticulture industry for recreational and ornamental purposes. Most of the material sold in the market is clonal material, often selected for particular desirable attributes. This means plants are often identical or from a narrow genetic base and therefore not desirable for broad-scale restoration projects.

Selected cutting material from stock mother plants often delivers better strike rates than cuttings taken from wild material.  However, in 2012 we were able to strike cuttings collected from numerous plants to ensure genetic diversity, confirming that a commonly used amenity horticultural approach could have merit for local restoration efforts.

Further trials

In the summer of 2014, hundreds of A. cuneatus cuttings were collected from healthy populations on the south coast and transported to Lullfitz Nursery in Perth. While it can be difficult to get good strike rates from A. cuneatus, we were very successful with a high strike rate. Our cuttings, which were originally about 5 cm had grown into approximately 30cm plants by the time they were planted back on the south coast in winter 2014. Planted cuttings were not irrigated and were essentially treated the same as any other nursery raised seedling. They were planted in an area where a previous revegetation attempt had failed.

Following good rains during spring 2014, the A.cuneatus had established themselves, and by the mid-summer of early 2015, the plants were thriving in their new habitat with very few deaths. The above process was duplicated in the Ranges Link area (Porongurup- Stirlings) with similar encouraging results. Bare-rooted cuttings were also planted at one Ranges Link site and high survival has been achieved.

This initial success has many people excited and Greening Australia is upscaling this technique to thousands of plants in current and future restoration works.

Funding for this project came from Commonwealth Government’s Biodiversity Fund via an arrangement with South Coast Natural Resource Management.

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