opportunities and constraints - analysis

Urban Forest Strategies

Extensive established urban forest network in both LGAs.

ToVP - 10% UFS canopy, targeting 20%. CoSP - maintain their 20% canopy coverage.

Residential gardens and verges

As LGA land is exhausted for planting, private gardens and verges can be utilised. Private gardens can be quite homogenous biotopes. They represent an opportunity to implement diverse, waterwise and bee attracting additional habitats. The ToVP offer verge plant giveaways and $500 grants for gardens. (D Boston, personal communication, May 1, 2023)

Collier golf course

36.4Ha of vegetation patches between fairways. Utilised by Carnaby cockatoos for roosting. Located on Bassendean soil. Established matrix of established trees (e.g. Pinus sp., Eucalyptus sp.)

Jirdarup Bushland Precinct buffer

Land surrounding Jirdarup remnant bushland suitable for additional native bee habitat. Land use generally compatible.

George St. Reserve is a designated contaminated site (Parcel ID: 13212), as is the Kensington Sand Pit (ID: 71752) which has been remediated for “restricted use”. Harold Rossiter Reserve represents additional potential understory flowering plant habitat.

Nearby Banksia Woodland

Remnants

Remnant bushland located nearby at Hillview Community Park in ToVP (1.6km from Jirdarup) and Goss Ave. in CoSP (2.4km from Jirdarup). Increased cross-pollination strengthens genetic diversity.

Research institutions / Education

Curtin University, Tafe, CSIRO, DBCA, Dept. Agriculture and Food as well as a number of schools occur in the area. Opportunity exists for living lab sites that are monitored and maintained , or even sponsored by these institutions.

Urbanisation / Infill

Fragmented matrix of suitable habitat and often reduced quality. ToVP anticipates an extra 19,300 dwellings required by 2050, while CoSP estimates 6000. Available public space for planting will plateau.

Niche floristics

Low diversity / exotic urban landscape doesn’t meet floristic requirements. Private property trees continue to be removed (CoSP estimates by 20% in UFS, 2018).

Climate change

Rainfall in the SW has decreased by 15% since 1970’s (BoM, 2022). Climate change will affect vegetation and thermal tolerances of bees (e.g. US study found 1oC increase resulted in 41% decrease in bee abundance (Ayers and Rehan, 2021).

Image credit: BOM, 2022.

Flight range

Due to their size native bees are constrained to ~0.5km foraging radius (1km flight range). As an oligolectic forgarer, R. ignita’s specialised flora must be within this flight zone.

Plant heightvehicle visibility / CPTED and bird safety around traffic

T. of V.P. advise <700mm for plants near roads for vehicle and pedestrian visibility. (D Boston, personal communication, May 1, 2023).

Phytophthora cinnanomi

Dieback is a root rot fungus that causes plant disease and death. Mid-story trees such as Banksia’s typically show signs of wilting when first infected (Davieson, 2014). Banksia cluster root systems can make them vulnerable. Ecologic (2014) indicates B. attenuata, E. marginata, X. preissii etc in Jirdarup reserve expected to “reliably express disease symptoms”

Image credit: Dept. of Natural Resources and Environment Tasmania

Melifera apis

Exotic plants gives the generalist European bee competitive advantage. Treatment of Varroa mite and viruses may pose a threat to native bees. Image credit: G. Brashaw