Figure 1: A map of the Fitz-Stirling landscape, an actively engaged operational area of Gondwana Link, where properties located between the Stirling Ranges and Fitzgerald River National Parks have been purchased and restored to increase the connectivity of this fragmented landscape. Clearly visable in the image are the Corackerup and Peniup Nature Reserves, along with 8 properties purchased specifically to contribute to the Gondwana Link vision. The 400 ha of cleared land featured in this case study - part of Bush Heritage Australia's larger Monjebup Reserve - is the dark green area circled in red.
Ecosystem type
Monjebup North's ecosystems are best defined as a semi-arid mixed mosaic of Open Shrub Mallee and Low Woodland vegetation associations. In 2011, Threshold Environmental Pty Ltd was commissioned by Bush Heritage Australia (BHA) to develop an Ecological Restoration Plan based on the analysis of soils, surrounding vegetation, and fauna habitat preferences. Seven main plant communities were identified for re-establishment according to soil type, including several types of Mallee, Open Woodlands, and a Swamp Woodland (Figure 2).
Figure 2: The broad ecosystem types as they could have occurred at Monjebup North prior to the clearing of 400 ha for agriculture. This map builds on soil sampling data and vegetation survey data.
Landscape condition
Monjebup North was purchased by Bush Heritage Australia for its significant proportion of remnant native vegetation in a global biodiversity hotspot (Figure 1). The property purchase included the acquisition of a 400 ha area of cleared agricultural land, which presented a zone of fragmentation between areas of remnant vegetation in the south of the property (Bush Heritage Australia's Monjebup Reserve) and the Corackerup Nature Reserve located to the north (Figure 3).
Figure 3: (click image to enlarge) Aerial image capturing the cleared areas on Monjebup North taken during a fly-over in 2009. The photo was taken from the northwest corner of the site, looking towards the southeast.
Restoration goals
The restoration of Monjebup North's cleared areas aims to significantly increase ecological connectivity within the local landscape. The outcomes of the project are conservation-focused, in particular the expansion of habitat access opportunities for the unique and diverse fauna and flora of the Fitz-Stirling region.
Works undertaken
After building a restoration map for the entire property in 2011, the north-western corner (100ha) of Monjebup North was subjected to a restoration program by Threshold Environmental Pty Ltd in 2012. Several restoration techniques were used (Figure 4), including:
Direct seeding of 8 different seed mixes matched to soil type (species count more than 100 species);
Planting seedlings of species across the whole site as well as in soil-specific “node” plantings;
Hand-broad seeding of ‘rare’ seed in patches of targeted soil types;
Development of habitat debris piles to encourage the return and occupancy of fauna, particularly ground-dwelling reptiles, marsupials, and native rodents;
On-site burning of serotinous species from the Proteacea family and subsequent in-situ seeding;
Chipping and mulching of select species for mechanical broadcast in contour graded ‘seams’.
Figure 4: (click image to enlarge) The 2012 post-restoration operational map showing the 7 meter tractor passes direct-seeding 8 different seed mixes across the entire 100 ha area, and the additional detailed, location-specific restoration treatments.
Threshold Environment Pty Ltd is currently implementing the restoration program for 150 ha on the eastern side of the property (2013).
Monitoring methodology
In November 2012, Threshold Environment Pty Ltd established a total of 21 long-term monitoring plots (15m x 15m) across the 8 vegetation systems seeded across the site. The monitoring counts all native species found within the plots, which enables identification of changes in germination, plant density and species composition over time (Figure 5).
Figure 6: (click imiage to enlarge) Visual output from two 15m x 15m monitoring plots following direct-seeding. The Y-axis captures 10 seeding rows (spaced at 1.4 m); the X-axis presents the exact location of each recorded germinant (m). Genera-specific germination data is presented using different symbols. The first monitoring results - 4 months after direct-seeding - indicate that there is strong germination across the site, with a good representation from all the main genera (Eucalyptus, Acacia, Melaleuca, Gastrolobium and Calothamnus). Excellent levels of survival for the hand-planted seedlings (mainly Banksia and Hakea species) were also noted. Monitoring will be ongoing.
Additionally, Bush Heritage Australia is also monitoring the site with a specific focus on the presence of vertebrate fauna and birds. To date, 10 monitoring locations have been established, including 5 locations within the re-vegetated area and 5 reference sites in adjacent remnant vegetation.
Lessons Learned and Future Directions
The restoration of patch-like vegetation communities as found in south-west WA requires a detailed approach which is at odds with industrial methods of broad-scale restoration. However, by layering different restoration treatments on top of each other, this contradiction can be overcome. For example, while the core vegetation structure and composition can be established through broad-acre direct-seeding, genetically viable sub-populations of less ubiquitous species can only be added through manual planting in specifically targeted soil types, thereby creating densely planted pockets of a given species ("nodes"). Future challenges lie in the restoration of heavy, impenetrable soils, the fine-tuning of seed quantities needed for direct-seeding, refinement of the design of habitat debris piles and other fauna microhabitat, and the successful establishment of sedges and native grasses.
Stakeholders and Funding
The restoration of Monjebup North is an initiative of Bush Heritage Australia contributing to the Gondwana Link vision, made possible through Wildlife Corridor funding by South Coast Natural Resource Management.
Contact details for this case study:
Threshold Environmental Pty Ltd
Justin Jonson, Director
P.O. Box 1124, ALBANY WA 6331, Australia
+61 (0) 427190465
jjonson@thresholdenvironmental.com.au
www.thresholdenvironmental.com