Transcript Urbanecosystems2[1] File

Urban Ecosystems cont’
• How green are cities?
– Impact of gardens and cemeteries
• Gardens a place for foreign invasion.
• Turning green again.
– Secondary Succession on wasteland
• Rural-urban fringes
– A fuzzy interface
• Wildlife corridors
– Connecting it all together
Green Cities?
City
Popln (2001)
% Area gardens
% Area open space
London
Birmingham
Liverpool
Leeds
Manchester
7 138 236
970 892
469 017
443 247
394 269
24
29
22
11
20
38
35
32
71
36
Urban Gardens
• Gardens, parks etc. are all managed
ecosystems.
• Many reasons for their management
• Results of management (depending upon
the reason for it) vary but have a
significant impact.
• Current issues are – paving, lawns, foreign
species & wildlife gardens.
Cemeteries – Not all bad news!
• By the late 18th century churchyards were full.
• New cemeteries developed around London and were
beautifully designed, landscaped and planted so as
to attract rich clients.
• Today they are important wildlife areas, esp. as not
always well maintained.
Photo: Abney Park.
It opened in 1840 and was laid
out with over 2,500 trees
rivalling the Royal Botanic
Gardens at Kew as a spectacle.
Introduction of new Species
• This can be planned (eg. Garden species
imported from abroad). Eg. Japanese
Knotweed (now a very invasive pest), or
Buddleia.
• Or unplanned (eg. Seeds brought in on
packaging and cargo).
• Can however, have a big impact upon
indigenous species who can be unable to
compete with the foreign species.
Oxford Ragwort
• Imported from Sicily in 1700 by Duchess of
Beaufort.
• Transferred to Oxford Botanic Gardens.
• ‘Escaped’ in 1720 and grew around Oxford.
• Railway tracks echo its natural niche.
• Railways connected
Oxford from mid 1800s
and facilitated spread of
plant nationally.
New species article
• http://news.bbc.co.uk/1/hi/sci/tech/753157
5.stm
• Read article and research one (non) and
invasive species in your group. 10 facts /
bullets on each.
Walls.
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•
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Create their own microclimates
Different aspect
Different substrates
Moisture levels vary significantly up the
wall
• Provide places of shelter for insects
More?
http://www.field-studies-council.org/urbaneco/urbaneco/wasteland/walls.htm
Rural-Urban Fringe
Defined in 1942 by George Wehrwein as
“the area of transition between well
recognised urban land-uses and the area
devoted to agriculture”.
Describe what the land uses you would
expect to find on both sides of this area.
Rural-Urban Fringe
Changes to this area on the rural side
include:
• Tourism and recreational pressures
• Pollution (including fly-tipping)
• Development pressures (250,000
houses planned around London over
next 25 years).
• Pressure to release Green-belt land
Rural-Urban Fringe
Changes to this area on the Urban side
include:
• garden creation (already discussed)
• Wildlife corridors
– Specific plans to connect wildlife ‘islands’
– Important link between rural and urban
areas
– May have varied land-uses
– Important in rural areas too where faming
practices reduce certain wildlife.
Rural-urban fringe case study
• Read the information about the Lee Valley
Country Park. And complete a spider
diagram on the following:
How has this Country Park and the associated human
activity affected the environment along the Rural-Urban
Fringe?
Ecological Conservation Area
Using the GeoFile sheet research one of the options and
make notes. Homework will be to complete the essay
and the questions on the GeoFile sheet.
With reference to examples, describe and explain how
urban areas can be managed to conserve and promote
ecological conservation.