Whole Perth Catalogue

Hotspot

In our biodiversity hotspot and Hotspot City, urbanisation is in conflict with ecology and biodiversity.

There are numerous intricate interdependencies between city and ecology. These flows, effects and synergies need to be better understood as hybrid and interconnected systems.

As an example, urban forms significantly impact groundwater recharge; these aquifers meet the deep tap roots of the banksia; these banksia provide vital habitat for endangered Carnaby’s black cockatoos.

Root architecture and attenuation on Banksia attenuata seedlings. Illustrated by Martin Thompson.

The taproots of many banksia species extend many metres below the ground to find the watertable. In cases where these levels are depleted, the Banksia woodlands will not survive. Illustration from Drake, Franks and Froend (2013).

Urban groundwater rechange is determined by the permeability of our urban designs and by soil types. Different methods need to be employed in different areas. For example, soakwells can cause many issues for water quality in clayey areas.

There are hundreds of thousands of private bores in backyards throughout Perth which extract water from the superficial aquifers. Thousands more regulated bores provide water for drinking and irrigaiton of public open space, argricultural and industrial uses, often drawn from the deeper aquifers.

An illustration by Philippa Nikulinsky of the Banksia grandis or Bull Banksia.

This is the Carnaby's black cockatoo or Ngoolark. The Carnaby's rely on Banksia woodlands across the Swan Coastal Plain as a primary food source. The disappearance of Banksia woodland, from land cleared or offset for urban development and groundwater drawdown, are threatening their extinction. Photograph by Georgina Steytler.