Download Biodiversity and Urban Streets

Biodiversity and Urban Streets
Urban Street Design for Engineers CPD
Session 3 – Constituent Elements
Engineers Ireland
Maryann Harris BSLA MSc Dip Law
Past-President, Irish Landscape Institute
Parks Services
Dublin City Council
Where we are: DMURS 2013
 No reference to Biodiversity in DMURS.
 Only reference to Green Infrastructure is in relation to
mitigate air pollution.
 Trees considered as spatial objects, not habitat.
 Continuous soil planting strips for trees
recommended – only ref. to soil
 No consideration of Soils in DMURS
 SuDS – directs to GDSDS (2005) – to be revised!
Understanding urban biodiversity
 Biodiversity = all living things – includes flora, fauna, soils!
 Exists at different levels: landscape, ecosystem, habitat
 Influenced by landscape context, history of city
 1,400 ha of public parks
and open spaces city-wide
 >2,000 ha of wetlands in
Dublin Bay, shallow, large
intertidal
 2 no. Natura 2000 sites
(both SPA and SAC) and a
National Special Amenity
Area in Dublin Bay
 3 main rivers - the Liffey,
Dodder and Tolka
- all flow into Natura 2000!
- all have wild salmon
stocks present - only
European capital city to
have this!
Characteristics of Dublin’s landscape context
Sensitive landscapes with urban impacts
How biodiverse is Dublin City?
 Dublin is 10th of all major European cities in terms of the area
covered by Natura 2000 sites
 These are sites designated by the European Union for the
importance of their habitats/species under EU Birds and
Habitats Directives
Characteristics of biodiversity in cities
1. Cities often have higher biodiversity due to influences of
humans and are often situated in naturally high biodiversity
areas e.g. harbours
2. Global and Irish urbanisation phenomenon = 60% of
population lives in cities, so urban biodiversity is nature for
many – an ‘artificial ecosystem’
3. Urban biodiversity can be more complex due to multi-causal
dynamics, more non-natives, niche habitats
4. Some species adapt to urban conditions better – generalists
better off than specialists, which become locally extinct
5. Not well-studied, ecological literature based on natural
habitats not urban – more complex to model
Threats to Biodiversity Globally (and Downtown)
1.
2.
3.
4.
5.
Habitat loss and fragmentation – urbanisation severs
Invasive species – along transport corridors
Population pressure – disturbance, pollution, volume
Climate Change – runoff, heat island effect, CO2
Overharvesting
Most of these threats occur in urban areas!!!
fragmentation
interior habitats and species decrease
interior habitat
edge habitat
edge habitats and species increase
EU law and designing to prevent fragmentation
 Article 10 of EU Habitats Directive requires:
‘land-use and development policies… to manage features of the
landscape which are of major importance for wild fauna and flora
and which by virtue of their linear and continuous structure… or
their function as stepping stones …are essential for migration,
dispersal and genetic exchange of wild species’
 Note: this legislation is inclusive of ALL species, not solely
designated flora and fauna!
 Streets can play a role in increasing connectivity of habitats
 Street design must be informed by landscape features of cities
 Green infrastructure strategies may exist in development plans
or LAP’s
What is Green Infrastructure?
 Green Infrastructure = an interconnected network of green
space that conserves natural ecosystem values and functions
and provides associated benefits to human populations
(Benedict and MacMahon, 2006)
 Emphasis on multi-functional and benefits to us, not just for
nature’s sake
 Ecological networks are boosted
 Cities are more resilient to disasters such as flooding
 Ecosystem services – what does nature do for us?
How to build GI into a city
Green infrastructure systems are spatially made of:
1. Core areas = nucleus of the network and provide
essential habitat for sensitive species
2. Hubs = buffering the core areas, the largest, least
fragmented continuous area of forest, wetlands,
stream systems, or other native landscape type
3. Corridors = maintain connectivity in the landscape
and provide for animal movement, seed and pollen
dispersal, and plant migration
Green Infrastructure policy in City
Development Plan
DCC GI Working Group for 2011-2017 Plan
 Overall public open
space: 5.09 ha/1000 pop.
DCC-owned: 2.96
ha/1000 pop.
 22% of the land area
within the city boundary
zoned Z9 = 2,580 hectares
as ‘recreational amenity
and open space’

 25% of city area is private
gardens
Distribution of Public Open Space Network
Areas Zoned in City Development Plan
Fundamentals of Urban Streets and Biodiversity
 Soil sealing and permeability – bare ground as
habitats
 Microclimate and trees – shelter, cooling,
evapotranspiration, energy production and
transfer, air purification and filtration
 Soils for bacterial action to convert waste
 Water as a resource - stormwater
Soil sealing
 Dublin has 50-79% degree
of soil sealing (EU)
 Bacterial processes in soil
can break down and treat
waste
 Soils as a biodiversity
resource and a living
medium as a buffer
 Effects on a city – paving
of front gardens in Dublin
 Soils management on site
Built and green space in Dublin region 2006 (Brennan et al
2009)
 Red zones show loss of green




space
Green zones show gains of
green space
22% of Dublin city is zoned as
green space, but patterns are
fragmented
10% open space requirement
as national planning policy but
no specific guidance on how
to structure it
The city centre has areas of
open space deficits
Continuous tree pit
(UK)
Suds retrofit in an urban street.
Source: Susdrain 2011
www.susdrain.org
Philadelphia Green Streets
watershed project: streets to
store stormwater
NYC Greenstreets Project: target CSO’s on a
street basis
Courtesy: Jim Mituzas, NYC Parks Dept.
Principles of street design for biodiversity
 Leave strips of soil large enough for vegetation to filter
runoff, provide habitat
 Look at green roofs on a street basis
 Leave adequate space for trees when designing
services layouts
 Ensure that connections to existing green networks
(parks, open spaces, cemeteries, waterbodies) are not
severed
Principles of street design for biodiversity
 Take back corners and unnecessary hardscape for
increased permeability and living surfaces
 Provide light and water for living things – don’t expect
growth on north-facing aspects
 Consider micro-climate e.g. ground temperature can
be elevated if shelter and foster insect life
 Lighting should minimise spill, only light what’s
needed to be seen
Designing for Biodiversity in Streets
 Adequate budget – for site survey, design, landscape
elements
 Adequate time – to survey when appropriate, to allow
establishment, to not leave as an afterthought
 Ecosystem services – there can be benefits for
humans as well as other wild species – health, shelter,
food resources, quality of life, amenity
 Look at potential hotspots, where street clusters can
augment existing networks, rather than fragmented
approach
 Allow for change and movement from disturbance
 Leave meaningful space for growth
 Connect to existing park networks as much as you can
Irish Urban Biodiversity Research Project
 EPA STRIVE Doctoral Programme (2012-B-PhD-10)
 ‘Enhancing biodiversity potential of urban parks
through improved management and public
engagement’
 EPA/UCD/DCC partnership
 Questionnaire to inform Irish guidance document –
please assist by completing today
 Survey of Irish professionals whose work can impact
on biodiversity in urban areas
Thanks!
[email protected]