A project to enable the Christmas Hills Landcare Group to take a strategic approach to managing the threat to our local biodiversity posed by weeds and rabbits.

Project aim
The aim of this project was to map the distribution of the more serious weed species, as well as rabbit warrens, on private properties in Christmas Hills, to enable the CHLG to take a strategic approach to the management of these threats to our local biodiversity.
Funding
Based on an initial cost estimate of $20,000 for a contractor to deliver this project, the CHLG sought funding from two separate sources for which applications were due at the same time.
An application for $9,800 was made to the 2007/08 PPWCMA Community Grants, and for $10,000 to the Norman Wettenhall Foundation. The PPWCMA Community Grants application was successful, whereas the Norman Wettenhall Foundation application was not.
We elected to proceed with the step of recruiting landholders willing to participate to enable us scope the project in more detail.
Letters were sent to all private land owners (approximately 180) in the Christmas Hills Landcare Group area. The mailing addresses were kindly provided by the Shire of Nillumbik. Each letter explained the purpose and method of the mapping project, and included a property access permission form, with stamped, return-addressed envelope, for landholders to grant permission for a CHLG representative to access their property for this project.
In response we received forms authorising access to 65 properties covering a total area of 721 hectares.
A project brief and contract tender specifications document was prepared and sent to four suitable contractors who were invited to submit a bid.
We received full proposals from two of these contractors – one bid totalled $86,550 and the other totalled $24,926.
The CHLG concluded that the $24,926 bid represented a realistic costing of the project, and sought the balance through an application to the philanthropic R.E. Ross Trust. Late in 2008 we learned that this application had not been successful, requiring us to rethink how best to complete this project with the available funds.
An alternative approach for achieving the outcomes was developed based on engaging a suitably skilled tertiary student, and equipping them with a GPS, laptop and GIS software.
Fortunately the investor agreed to a project variation, including an extension to the expected completion date.
11 days after receiving notification of the variation agreement, the Black Saturday bushfires swept through parts of Christmas Hills further delaying implementation of this project.
Method
We purchased a refurbished laptop, external hard drive, GPS and GIS software (approximately $2,000 in total), and engaged the services of a third year Deakin University student to undertake the mapping and GIS layer creation using this equipment.
Each participating landholder was notified of the engagement of the student, who then contacted each landholder to arrange a mutually suitable time to access their property.
Often with assistance from the landholder, the location of any rabbit warrens and infestations of the ten weed species on each property were recorded either using the GPS, or by marking up a hard copy aerial photo of the property.
A field estimate of the density of weed infestations was also recorded.
This data was the digitised by the student, to create separate GIS layers for each weed species.
Results
Field data was collected from 61 properties covering 698 ha (some owners who had previously granted access permission had either changed their mind, or were unable to be contacted).
Four A0 maps were then prepared, printed and laminated to depict the distribution of each weed species, and the rabbit warrens, and their spatial relationship to different EVCs, property boundaries, group member properties, etc.
Weed species mapped
The ten environmental weed species identified by the CHLG as priorities for mapping were:

Bridal Creeper (Smilax) Asparagus asparagoides

Brooms Cytisus scoparius, Genista monspessulana, G. linifolia

Sweet Pittosporum Pittosporum undulatum

Blackberry Rubus spp aggregate

Spanish Heath Erica lusitanica

English Ivy Hedera helix

Boneseed Chrysanthemoides monilifera

Bulbil Watsonia Watsonia meriana

Cootamundra Wattle Acacia baileyana

Radiata Pine Pinus radiata
 
PDF maps depicting the data collected are available here