Increasing Urban
Biodiversity Using
Green Infrastructure
Dr Nicholas (Nick) Williams
School of Ecosystem and Forest Sciences
[email protected]
www.thegirg.org.au
Global Urban Biodiversity
• Cities support a substantial proportion of the
world’s biodiversity
– >20% of the world’s bird species
– > 5% of the world’s plant species
• Density of bird and plant species (# of spp
/km2) has declined substantially:
– only 8% of native bird and 25% of native plant
species are currently present compared with nonurban estimates.
Aronson M.F.J., La Sorte F.A., Nilon C.H., Katti M., Goddard M.A., Lepczyk C.A., Warren
P.S., Williams N.S.G., Cilliers S., Clarkson B., Dobbs C., Dolan R., Hedblom M., Klotz S.,
Kooijmans J.L., Kühn I., Macgregor-Fors I., McDonnell M., Mörtberg U., Pyšek P., Siebert S.,
Sushinsky ., Werner P. & Winter M. 2014. Proc. R. Soc. B 281: 1780
Global Urban Biodiversity
Species persistence
• Cities have extinction debts that are likely to
be paid in the near future.
1.0
0.8
Extinction debt
0.6
0.4
0.2
0.0
0.0
0.2
0.4
0.6
0.8
1.0
Current proportion native vegetation
Hahs, A.K., McDonnell, M.J.,
McCarthy, M.A., Vesk, P.A.,
Corlett, R.T., Norton, B.A.,
Clemants, S.E., Duncan,
R.P., Thompson, K.,
Schwartz, M.W. and Williams,
N.S.G (2009) A global
synthesis of plant extinction
rates in urban areas. Ecology
Letters 12, 1165-1173
To retain urban biodiversity:
• Stop destroying and degrading remnant
habitats as cities expand
However, we can’t create more remnant
habitat. So we need to:
• Manage existing remnant habitats better
• Create new habitat in areas not currently
managed for biodiversity
This means integrating habitat into existing
urban land use = reconciliation ecology
Key Question
Can we use green infrastructure
to improve urban biodiversity?
• Green infrastructure is the network of
natural and designed vegetation elements
within our cities and towns, in both public
and private domains
Green Infrastructure
Urban recreational parks
Forest remnants
Streetscapes
Green roofs
Golf courses
Residential gardens
Example 1:
• Using existing green
infrastructure to improve
biodiversity outcomes?
Example 2:
• Creating biodiversity
habitat where there was
none previously
Example 1: Ecosystem services from large
urban green spaces: the biodiversity and
carbon benefit of urban golf courses
Investigators: Dr Stephen Livesley, Dr Nick Williams, Prof Nigel
Stork, Dr Amy Hahs, Dr Caragh Threlfall, Dr Ken Walker
Students: Alessandro Ossola, Luis Mata, Jess Mackie, Lee
Wilson, Jarvis Mihsill, Virginia Harris
Research Assistants: Alessandro Ossola, Jess Mackie, Jarvis
Mihsill, Virginia Harris, Luis Mata
Project design
~10 km
• 13 neighbourhoods
• Age = 5-110 years
• Management regime –
vegetation structure
Project Design
Brighton, VIC
~10 km
• 13 neighbourhoods
• Age = 5-110 years
• Management regime –
vegetation structure
Cranbourne, VIC
Project Design
Survey plots in different forms of urban green infrastructure
e
Vegetation Variables
In each plot we measured:
•Biomass
• Understorey Volume
(Structural complexity)
• Floristic composition
• % Indigenous sp.
• Tree DBH
• Tree Density
• # of large native trees
• % Impervious surface
(landscape)
Vegetation Structure
STRUCTURAL COMPLEXITY – the vertical arrangement of the habitat
HIGH
LOW
30 m
Measuring Understorey Volume
20 m
Understorey Volume varied in GC
Structural Complexity (%)
50
40
30
20
10
0
0
20
40
60
Site Age (years)
80
100
120
Understorey volume across urban
green space types
Structural Complexity (%)
50
40
30
20
10
0
Golf Course
Garden
Park
Link between vegetation, biodiversity
and ecosystem services
Bees
Birds
• Pollinators
• Sensitive to
disturbance
• Seed dispersal,
insect pest
control
• Sensitive to
change
Beetles and Bugs
Bats
• Insect pest
control
(predators)
• Insect pest
control
Invertebrate Surveys
• Targeting bees, bugs and beetles
• Daytime and night time sampling
• Repeated in summer and spring 2012
Light Trap
Pan Traps
Sweep Net
Beetles (Coleptera)
• Collected over 40,000
beetles in light traps
• 197 morpho-species
• Most abundant families
were Carabidae,
Scarabaeidae and
Hydrophilidae
Hydrophilidae
Carabidae
Griffith Uni Honours Student Jess Mackie
Scarabaeidae
Average Beetle Abundance
Beetles (Coleptera)
1200
1000
800
600
400
200
0
Golf Course
Gardens
Parks
True Bugs (Hemiptera)
• Collected 9500 bugs in
sweep nets & light traps
• 119 species
Luis Mata
• Most abundant species
were herbivores, predatory
bugs appear to be sensitive
to site conditions
Mutusca sp
Nabis sp
True Bugs (Hemiptera)
600
(individuals per plot)
Average Bug Abundance
700
Secondary rough has
more than double the
abundance of predatory
bug species
500
400
X
300
200
100
0
Golf Course
Gardens
Parks
Bees
• ~2000 native species in
Australia
• >150 species in
Melbourne
• Apis melifera introduced
• Essential for plant
pollination
• No Australian urban bee
ecology studies to date
Photos: Ken Walker
Bees
10
Bee Species Richness
9
8
7
6
5
4
3
2
1
0
Golf Courses
Gardens
Remnant Heathlands
Homalictus sp.
Bees
• 19 species: Colletids,
Halictids, Megachilids and
Apis
Halictid– pointed tip
• Halictidae: most abundant
and widespread
o “Trash” bees – because of
their short, pointed tongue
• Colletidae: Specialised
short, broad tongued bees
were the least widespread
Photos: Ken Walker & WA
Museum
Colletid – broad tip
1.5
Bee Communities
Golf Course
Residential
Urban Parks
0.0
-1.0
Halictids
-0.5
NMDS2
0.5
1.0
Colletids
Green Space
ANOSIM p<0.01
-1.5
Stress 0.2
Apis
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Bee Community Drivers
Environmental vectors p<0.01
1.5
Green Space
0.0
-0.5
-1.0
Flower Diversity
Plant Diversity
-1.5
NMDS2
0.5
1.0
Nativeness
Tree Health
Vegetation Structure
Golf Course
Residential
Urban Parks
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
Bees
• Bee community changed
based on:
o Floristics
o Vegetation structure
• The most diverse
communities & specialised
species found in older,
native parks and golf
courses
Bird and Bat Surveys
Birds:
– 3 repeat, early morning
surveys in Spring/Summer
– Used stopping rules to
survey areas of different
sizes
Bats:
– Ultrasonic recording for
multiple nights
Anabat Bat Detector
Birds Species Richness
• Recorded 106 species
• 60 species in one golf course
• Min # seen in golf courses was
always greater than the
maximum recorded elsewhere
Average Bird Species Richness
35
30
25
20
15
10
5
0
Golf Course
Residential
Garden
Urban Park
Average Incidence of Breeding
Breeding Birds
10
9
8
7
6
5
4
3
2
1
0
Golf Course
Residential
Garden
Urban Park
Insect-eating Bat Sp. Richness
Average Bat Species Richness
• We recorded 24,000 bat calls from 14 species
• Bats in every course, park and yard – some golf
courses had 10 bat species
9
8
7
6
5
4
3
2
1
0
Golf Course
Residential
Garden
Urban Park
300
250
200
150
Freq kHz
Average Bat Activity
350
Freq kHz
Insect-eating Bat Sp. Activity
Time ms
100
50
Time ms
0
Golf Course
Residential
Garden
Urban Park
Modelling
• To understand the effect of vegetation
management on bird and bat communities, we
fitted generalised linear models (GLM’s) using
highest ranked of 7 vegetation variables.
• Ranked by Akaike Information Criterion
corrected for small sample size (AICc).
• All analyses were conducted using ‘R’
a)
12
Bird Breeding Activity
30
25
20
15
10
0.2
0.3
0.4
6
4
2
0.5
% Understorey Volume 0.0 - 0.5m
30
25
20
15
10
0.1
0.2
0.3
0.4
0.5
Prop Locally Indigenous plants
0.0
Insectivorous Bird Species Richness
0.1
35
Bird Species Richness
8
0
0.0
b)
10
0.1
0.2
0.3
0.4
0.5
% Understorey Volume 0.0 - 0.5m
12
10
8
6
4
2
0.0
12
0.1
0.2
0.3
0.4
0.5
% Understorey Volume 0.0 - 0.5m
c)
12
Bird Breeding Activity
Bird Species Richness
35
Insectivorous Bird Species Richness
Bird GLMs
10
8
6
4
2
10
8
6
4
2
0
0.1
0.2
0.3
0.4
0.5
Prop Locally Indigenous plants
0
5
10
15
No. trees >81cm DBH
20
Bat GLMs
600
Vegetation is
influencing
bat richness
and activity
through
insect
abundance
500
8
Bat Activity
Bat Species Richness
10
6
400
300
200
4
100
2
0
0
1000
2000
3000
4000
5000
0
600
600
500
500
400
300
200
0
0.4
0.5
5000
0.6
Prop Native Plants
0.7
More
vegetation =
> insect
density &
diversity = >
bat diversity
and foraging
activity
200
0
0.3
4000
300
100
0.2
3000
400
100
0.1
2000
Insect Abundance
Bat Activity
Bat Activity
Insect Abundance
1000
0
5
10
15
No. trees >81cm DBH
20
Summary
• Large urban green spaces,
particularly golf courses,
have high biodiversity value
• But this varies with
vegetation management
• Results provides information
about how to modify green
infrastructure to improve
biodiversity
• Urban recreation and
biodiversity conservation are
compatible
Summary: Greater vegetation
structure = more biodiversity
HIGH
LOW
Example 2: Invertebrate Biodiversity
on Melbourne’s Green Roofs
Investigators: Dr Nick Williams, Dr Caragh Threlfall, Dr Briony
Norton, Dr Ken Walker
Students: Jacinda Murphy
Green Roofs & Biodiversity
• Green roofs increasingly common in cities
• Could support urban biodiversity but only a
small % specifically designed for this
• Biodiversity benefits claimed by industry
– compensate for lost habitat
– provide pollinator resources, rare species habitat
– Increase connectivity
• BUT few studies have rigorously evaluated
biodiversity benefits of green roofs
Williams, N.S.G, Lundholm, J.T., MacIvor, J.S. (2015) Can
green roofs help urban biodiversity conservation? Journal
of Applied Ecology 51: 1643-1649
Invertebrate Diversity on Extensive
Green Roofs in Melbourne
Questions:
Monash Council - Succulent Green Roof
1. Do green roofs compare to
similar ground-level habitat?
2. Are grassland green roofs
specifically designed for
biodiversity better than
“traditional” succulent green
roofs?
3. What features of roofs influence
invertebrate communities?
• Sampled insects using pan and
pitfall traps on 6 green roofs
Minifie Park Grassland Green Roof
Companion site: 501 Swanston St, Melbourne
Nearby site: Scots Church
Green roof: Council House 2
Invertebrate Abundance
• Collected >30,000
individual inverts
• Roofs had fewer
individuals that
adjacent ground level
habitats
6000
Invertebrate Abundance
a
5000
4000
3000
a
2000
1000
b
0
Companion
Nearby
Roof
Invertebrate Abundance
9000
• There was no
difference between
‘grassland’ &
succulent roofs
Invertebrate Abundance
8000
7000
6000
5000
4000
3000
2000
1000
0
Companion
Roof
Grassland
Companion
Succulent
Roof
Types of invertebrates
• Often claimed roofs can support
a similar suite of inverts to
ground-level, including pollinators
• We found evidence of this
– Same 8 species of bees and
hoverflies found in all sites
– Providing pollination services
• Some groups of invertebrates
were under-represented
– Millipedes, slaters
Photos: Ken Walker
Feeding guilds
100%
Predator
90%
80%
Nectarivore
% of catch
70%
60%
Omnivore
50%
40%
Herbivore
30%
20%
Detritivore
10%
0%
Companion
Nearby
Roof
What features of roofs influenced
invertebrates?
• Proximity to surrounding
green areas
– Influences connectivity,
dispersal, colonisation
• Age
– Older roofs were more
biodiverse
– But most grassland roofs are
young
• Height
– Roofs lower to the ground
were more biodiverse
Urban Green
Infrastructure
Management
Recommendations
Increase vegetation complexity
• Revegetate with native plants
– Target out of the way,
unused areas
• Weed removal
• Encouraging natural
regeneration by
– Reducing mowing
– Fire
Retain large trees
Trees are:
– Critical habitat for bats,
birds, reptiles,
invertebrates......
– Provide connectivity at the
landscape scale
– Socially, culturally and
aesthetically important
– Long lived assets that are
expensive to replace
Retain leaf litter
Important for:
• Invertebrates
• Predators of
Invertebrates
• Water infiltration
• Seed germination
Retain Coarse Woody Debris
Important because they provide:
• shelter for nesting and refuge
from the environment.
• foraging sites for many different
animal species.
• sites for water infiltration,
nutrient capture and fungi
growth.
• assist organisms move through
the landscape.
Barton et al (2009) Conserving ground-dwelling beetles
in an endangered woodland community: multi-scale
habitat effects on assemblages diversity. Biological
Conservation , 142, 1701-1709
Supplement Scarce Resources
Beetle Banks: Piles of
decaying wood provide
important beetle habitat
rare in urban areas
Bee Hotels: Native
bees nest in hollow
twigs and soil
Green Roof Biodiversity
Green roofs in dense urban
areas will attract less biodiversity
than those near remnant
habitats, parks
Green Roof Biodiversity
• Higher green roofs will attract less biodiversity
than those lower or at grade
Chicago
Moos water filtration plant Switzerland
Green Roof Biodiversity
• Provide fauna resources
– Different substrate types
– Logs
– Water
– Rocks
Sharrow School, Sheffield,
Bee hotels
Pyrenees Green Roof
Augustenborg Botanical
Roof Garden Malmö,
Sweden
Write Design Guides
Get advice to those who
need it
Merci beaucoup
• For funding my travel
• Danielle Dagenais for inviting me
• My research group, (particularly Caragh
Threlfall)
www.thegirg.org.au
• Funding agencies