Python Notes for mca i year students osmania university.docx
Sustainable Cities: Urban Ecology
1. PLAN 1900: Sustainable Cities
Week 14: Urban Ecology
Anuradha Mukherji
Assistant Professor of Urban and Regional Planning
2. URBAN ECOLOGY
• Study of human dominated eco-systems, i.e., cities – system
where human species is a central agent
• Urbanization ‘fragments, isolates, and degrades natural
habitat, disrupts hydrological systems, modifies nutrient
cycling”
• Cities and rapid urbanization impact ecological functions –
Ecological functions are the building blocks of specific habitat
types on which species depend.
• Disruption to ecological functions including physical habitat
results in a change or loss in habitat type.
3. INTEGRATING ECOLOGY
• Integrating ecology into cities is essential to sustainability
• Can help mitigate human impact on ecosystems
• Enhances ecosystem services (i.e., the combined actions of
species in an ecosystem that perform functions of value to
society, such as production of oxygen, decomposition of
waste, pollination)
• Protects biodiversity (i.e., the variety of life forms indicated by
numbers of different species of plants and animals in an
ecosystem)
• Maintains a healthy functioning planet for future generations
4. GREEN NETWORKS SYSTEM
System of interconnected or related patches and corridors that
provide and sustain ecological values within a human
dominated landscape.
Goal is to preserve or restore the ecological integrity of critical
natural systems while allowing for compatible human activities
within the network and productive use of adjacent lands.
Ecological integrity is the health, structure and functioning of an
ecosystem consisting of near natural levels of production,
biodiversity, soil and water.
5. GREEN NETWORKS HIERARCHY
System linked at multiple scales:
1. Mega – significance at continental level
2. Macro – National and regional levels
3. Meso – City level
4. Micro – Individual projects and sites
Linking scales creates possibility for connectivity and flows
between levels that are essential for sustainability
6. EUROPEAN GREEN BELT
This image is attributed to Smaack @ 2011 (CC BY-SA 3.0)
Old forest area along eastern European borders
Multinational movement to conserve & protect
Connects national parks, nature parks, biosphere reserves
7. GREEN NETWORK EXAMPLE
Lifelines: Rivers, Streams, and Riparian Areas
1. Biologically most diverse and rich
2. Critical lifelines for providing connectivity that facilitates
flows
3. Important to preserve these critical corridors
4. Most places, rivers, streams and their drainage basins are
modified from their original condition
5. Sometimes channelized or straightened to manage flooding
or maximize land for urban development
6. In the long-term this increases the speed of water flow, in
turn the force causing erosion of stream banks, thus
carrying more sediment & reducing water quality.
7. The sediment load drops downstream, filling the channel,
reducing carrying capacity for water, resulting in flooding
beyond historical flood zones.
9. Enz River, Pforzheim, Germany
City of 120,000 at the edge of Germany’s Black Forest
River runs through center of town and was channelized and straightened in
early 1900s
Land adjacent to river developed through decades of urban housing, industrial
complexes, shops and other intense urbanization
A river restoration project as part of large scheme to create an urban park
following the natural course of the river for 15 km through the city
Re-naturalization process reintroduced the normal meander cycle of river prior
to channelizing, with trees and shrubs replanted
Now 20 years later, the river corridor is well established, vegetation has
matured providing species habitat, many ecological functions restored
Ecological corridor linking Black forest to other ecological zones
12. GREEN NETWORK EXAMPLE
Sources and Core Areas: Urban Nature Preserves
1. Large areas of natural or near natural landscapes
2. Prime habitat for various species
3. Improve air quality – supply oxygen & remove carbon
4. Mitigates urban heat island effect
5. Perform hydrological functions – water retention,
groundwater recharge, surface water filtration
13. The Phoenix Mountains Preserve, Arizona, USA
This image is attributed to
City of 120,000 at the edge of Germany’s Black Forest
River runs through center of town and was channelized and straightened in
early 1900s
Land adjacent to river developed through decades of urban housing, industrial
complexes, shops and other intense urbanization
A river restoration project as part of large scheme to create an urban park
following the natural course of the river for 15 km through the city
Re-naturalization process reintroduced the normal meander cycle of river prior
to channelizing, with trees and shrubs replanted
Now 20 years later, the river corridor is well established, vegetation has
matured providing species habitat, many ecological functions restored
Ecological corridor linking Black forest to other ecological zones
An example of open-space preserves that function as core areas
All natural or near-natural condition & part of the city of Phoenix Park System
Largest city park in the United States comprising – South Mountain Park, North
Mountain Range, and Sonoran Preserve
15. The Phoenix Mountains Preserve, Arizona, USA
Downtown Phoenix from South Mountain
This image is attributed to
City of 120,000 at the edge of Germany’s Black Forest
River runs through center of town and was channelized and straightened in
early 1900s
Land adjacent to river developed through decades of urban housing, industrial
complexes, shops and other intense urbanization
A river restoration project as part of large scheme to create an urban park
following the natural course of the river for 15 km through the city
Re-naturalization process reintroduced the normal meander cycle of river prior
to channelizing, with trees and shrubs replanted
Now 20 years later, the river corridor is well established, vegetation has
matured providing species habitat, many ecological functions restored
Ecological corridor linking Black forest to other ecological zones
16. GREEN NETWORK EXAMPLE
Gray to Green Infrastructure: Transport & Utility Corridors
1. Roads, rail lines, and utility corridors form barriers, interrupt
flows & accelerate fragmentation
2. Ecological bridges & eco-ducts used to overcome the
barriers
3. Infrastructure travels through wide rights of ways – residual
space beside roads & rails or underneath utility lines can be
ecological corridors (e.g., for animal migration corridor) –
safer for motorists on roadways
17. Wildlife Overpass, Banff National Park, Canada
This image is attributed to Qyd @ 2006 (CC BY 2.5)
18. Watchung Reservation, I-78, New Jersey
Bridge for animal crossing
This image is attributed to Doug Kerr @ 2009 (CC BY-SA 2.0)
19. GREEN NETWORK EXAMPLE
Forgotten Space: Vacant Land, Underutilized Sites, and
Brownfields
1. Vacant, underutilized land and derelict or post-industrial
brownfield sites are a resource
2. Brownfield sites were previously occupied, often in some
industrial capacity, and are now abandoned and may have
contamination issues
3. A study of 70 cities in the United States showed that 15% of
land on average is vacant
4. Often privately owned, these parcels can play a role in
establishing green networks or provide linkages between
other ecological zones
5. Example: BP Park in Waverton Peninsula, Sydney. A former
BP storage depot with 31 oil tanks carved into sandstone
bedrock. Bio-remediation carried out.
