EVSC30006 Lecture Notes - Lecture 19: Urban Growth Boundary, Sloss Debate, Urban Design
1 Jun 2018
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LECTURE 19: RESERVE DESIGN IN URBAN AREAS
• Nature reserves are areas reserved for nature or natural values
o Include protected areas, national parks, wilderness areas, informal & formal green space
o Form a network of reserves where biodiversity values can persist
• In urban design, happens at 2 frontiers:
o Expansion of Urban Growth Boundary:
▪ Direct development to areas with lowest impact on biodiversity through mapping biodiversity
values
o Planning & development of existing green spaces – maintain biodiversity within city boundaries
• Persistence: need to think about amount of habitat, habitat quality, reserve shape & connectivity
• Currently unaware of how much area & connectivity is need – should promote pop dynamics & long-term viability of
species
o SLOSS debate: single large or several small
RESERVE PLANNING & DESIGN
• 2 fundamental questions:
o Where are the most important areas?
▪ Use species as measure of biodiversity – most agreed on & most data
▪ Main target to protect as many species as possible, given limited space in urban areas
o What is the correct amount of green space needed to maintain ecological function?
Spatial Prioritization
Scoring
• Look at characteristics of site & rank them (scoring)
• Based on selected attributes – including species richness, rarity & endemism
• Commonly used, relatively easy and fast
• Issues: no set to do it – subjective & non-transparent, if you take top scores may be protecting
same species twice, doesn’t measure network as a whole within the landscape
Complementarity-
based Approach
• Select sites that best complement each other in respect to the objective
• Measure attributes of the network, as well as individual sites
• Cost-efficient, should be chosen over scoring
• First protect patch with largest number of species, then patch with largest number of
unprotected species
INSIDE THE URBAN GROWTH BOUNDARY
• Focus on how to maintain & expand ecologically functional network – layout for green space predicted by decisions
made on UGB
• Maintain/restore – local habitat quality and connectivity
• Current debate between land sparing and land sharing – highly dependent on species
o Need more knowledge on housing density, configuration, softening the matrix & cumulative impact on
biodiversity of cities as a whole
Land Sparing
• Retention of large, isolated, patches of habitat
• Land developed intensively
• Requires less land, leaving more area untouched
Land Sharing
• Land developed less intensively – more, smaller green spaces
• Requires more land but allows co-existence of humans and nature
• Connectivity means individuals can disperse, allows populations to survive in urban areas
Document Summary
Lecture 19: reserve design in urban areas: nature reserves are areas reserved for nature or natural values. Include protected areas, national parks, wilderness areas, informal & formal green space. Form a network of reserves where biodiversity values can persist. Expansion of urban growth boundary: direct development to areas with lowest impact on biodiversity through mapping biodiversity values, planning & development of existing green spaces maintain biodiversity within city boundaries. Persistence: need to think about amount of habitat, habitat quality, reserve shape & connectivity: currently unaware of how much area & connectivity is need should promote pop dynamics & long-term viability of species. Look at characteristics of site & rank them (scoring) Based on selected attributes including species richness, rarity & endemism: commonly used, relatively easy and fast. Issues: no set to do it subjective & non-transparent, if you take top scores may be protecting same species twice, doesn"t measure network as a whole within the landscape.
