EVSC30006 Lecture Notes - Lecture 3: Growling Grass Frog, Urban Growth Boundary, Yarra River
1 Jun 2018
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LECTURE 3: CHARACTERISTICS OF URBAN LANDSCAPES
• Expansion for previously rural areas, being transformed into urban land use on the urban growth boundary
• Microclimates have changed due to black colour of roofs and impervious surfaces
• Development of technology has allowed cities to develop in previously inhospitable places
o Dubai, Phoenix – ability to manipulate natural systems for use of humans – temperature, water
• UHI Effect: heat experienced overnight becoming more extreme, buildings holding heat
o Most pronounced in still with no clouds conditions – 7-10 degrees difference
Melbourne
• Inner city: 1.66% remnant vegetation – average patch size 1.4Ha
• Outer city: 16% remnant vegetation – average patch size 6.8Ha
• C.C: annual frost days majorly reduced from 1850-2000 and 1 degree of warming since 1950
• Wetland & stream systems altered by humans – Yarra River constrained without variety
PRIMARY BIOPHSYCIAL PROCESES OF URBANISATION
• Removal of vegetation, often indigenous and/or native
• Construction of buildings and roads
• Replacement of permeable surfaces with impermeable surfaces
• Reduction of open space
• Production of pollution and waste
• Increase noise and artificial light
• Decline in tree cover along the urban-rural gradient – inverse relationship
to impermeable surfaces
SECONDARY BIOPHSYCIAL PROCESES OF URBANISATION
• Habitat loss, isolation and fragmentation
• Loss of habitat complexity
• Climatic and weather changes
• Altered hydrological regimes
• Pollution of water
o Changes to water quality: increased pollutants, turbidity,
including nitrogen & phosphorous compounds
• Pollution of air and soil
o NOx, CO, CO2 & SO2 particulates
o Heavy metals in soil, including nitrogen deposition
• Altered noise and light regimes
• Growling Grass Frog: lives in gardens around the city, noise
impacts ability of organisms to communicate via sound
Hydrological Changes
• Imported potable water & wastewater
• Increased volumes and flow rate of stormwater runoff to urban streams
• Pollutants arrive in stream quickly and untreated
• Gouging of urban stream channels resulting in increased flows
• Urban landforms are often modified to reduce lateral flooding
• Streams, floodplains, deltas & estuaries may be modified
• In urban areas: quick increase in flow, then low base flow – short lag time between rainfall event & runoff
Document Summary
Primary biophsycial proceses of urbanisation: construction of buildings and roads, decline in tree cover along the urban-rural gradient inverse relationship. Removal of vegetation, often indigenous and/or native to impermeable surfaces. Secondary biophsycial proceses of urbanisation: habitat loss, isolation and fragmentation, climatic and weather changes. Loss of habitat complexity: altered hydrological regimes. Pollution of water: changes to water quality: increased pollutants, turbidity, including nitrogen & phosphorous compounds. Increased volumes and flow rate of stormwater runoff to urban streams. Pollutants arrive in stream quickly and untreated: gouging of urban stream channels resulting in increased flows, urban landforms are often modified to reduce lateral flooding. Streams, floodplains, deltas & estuaries may be modified.
