Science Seminar Series 12 Sean Connell
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Environment Institute Science Seminar Series 2009 Final Seminar Sem 1: 29 June – 12pm Policy responses to a drying climate may save Adelaide’s kelp forests Presented by: Associate Professor Sean Connell
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Associate Professor Sean Connell presents the topic ‘Policy responses to a drying climate may save Adelaide's kelp forests’. Sean’s seminar is based on 10 years of experimental analyses of observations derived from the natural history of temperate Australian kelp forests. Theory-centric observations can hamper science and he happily admits where his prior biases have caused mistaken starts. Sean argues that if such bias of theory-centric science can be recognised as a possible model, its correctness can be investigated. Sean notes that a modern bias is our culture for alarming news of ecosystem change, he sees it as playing an increasing role in ecology; in not only what is funded and published, but also in how data is acquired and interpreted. Sean indicates that less research seems constructed to survive beyond short-term headlines. He passionately advocates that if we can recognise the theory-laden traps that seek to account for the will-o'-the-wisp, we may return value to research programs that are less about chasing ambulances and wild geese.
Transcript of Science Seminar Series 12 Sean Connell
Environment InstituteScience Seminar Series 2009
Final Seminar Sem 1: 29 June – 12pm
Policy responses to a drying climate may save Adelaide’s kelp forests
Presented by: Associate Professor Sean Connell
is playing an increasing role:
funded and published
how data are acquired and interpreted
“Since the Jamaica story was an anomaly, it makes a poor foundation for general models of reef ecology” Bruno et al. 2009 Ecology
In a race for $ and the headlines needed to lobby $...
If theory ladnness can be recognised as a possible model
Policy
1. Reconstruction of a lost-baseline
2. Drivers of habitat-loss
3. Solutions for restoration
4. Contingencies via biogeography
an immersion of science
5. Contingencies via climate
NN
Australia
Australia
South
AdelaideUrban 1
Agricultural 1
Natural 1Natural 2
Urban 2
Victor Harbor
Adelaide
25 km
Agricultural 2
South North
Sites
#1. Baseline
Cape Leeuwin
Encounter Bay
#1. Baseline
#1. Baseline
# 2. Causes
0.00
0.20
0.40
0.60
0.80
0.00
0.10
0.20
0.30
0.40Heavy rainfall
Light rainfall
Me
an
NO
x c
on
c.
he
avy (
mg
L-1
)
Me
an
NO
x c
on
c.
ligh
t ra
infa
ll (m
g L
-1)
Urban Agricultural Natural
Catchment type
# 2. Causes
Diameter of habitat patches (m)
20
0
10
0
10
20
0
Tu
rf-f
orm
ers
Can
op
y-f
orm
ers
Urban Agricultural Natural
10 3020 0 10 3020 0 10 3020
PA
TC
H-S
IZE
FR
EQ
UE
NC
Y
40
mean: 5.9 mean: 9.5 mean: 11.4
mean: 4.1 mean: 3.4 mean: 2.3
# 2. Causes
δ13C (‰ SE)
δ1
5N
(‰
S
E)
Urban Agricultural Natural
Ch
an
ge
in δ
15N
(‰
SE
)
(a)
0
2
4
6
4
6
8
10
12
-22 -21 -20 -19
AgriculturalNatural
Urban
(b)uptake of urban derived nitrogen
# 2. Causes
# 2. Mechanisms
Urban catchmentNatural catchment
Elevated Nutrients
Ambient Nutrients
Elevated Nutrients
Ambient Nutrients
Summer WinterWinterSummer
Pe
rce
nta
ge
co
ve
r o
f tu
rf
20
40
60
80
100
0
# 2. Mechanisms
# 3. Restoration
Recovery
(%
)
Turf-dominated sites
1 2 3
Turf removal
Non-removal control
0
20
40
60
80
100
Contingencies
Production & consumption via humans & biogeography
#4. Contingencies
Human population
Envir
onm
en
tal Im
pa
ct
Perth
Adelaide
Sydney
Bigger cities = bigger impacts?
#4. Contingencies
• Oceanography
0.5 1.0 1.5
0
10
20 Eastern AustraliaSouthern AustraliaWestern Australia
0
% c
ove
r of tu
rf
Chlorophyll a
Sydney
Southern Eastern
0.0
0.1
0.2
0.3
NO
x (
Mill
igra
ms/l)
a b a b
insitu sampling at depth of subtidal habitats
Sydney
0
5
10
15
20
Southern Eastern
Chlo
rop
hylla
(mg l-1
)
Sydney
• Oceanography
1000 Km
Cape Jervis
Tu
rfs
(% c
ove
r)0
5
10
15
20
25
south coast
49.64%
Ambient
Enriched 7.25 %
eastcoast
• Oceanography
2 4 6 8 10 12 14
1000
2000
3000
4000
5000
6000
SE Alaska
Southern California S Chile
East AustraliaSouth & West Australia
Norway
Gulf of MaineS Africa-South CoastP
rod
uctivity
Integrated Monthly NO3 Flux
JapanCentral California
The poster child
easy ecology
• Consumers
75 % (n = 113 sites) have no barrens
Data courtesy of Nick Shears
70 % (n = 60 sites) have no barrens
1000 Km
Cape Jervis
0
20
40
60
80
100
Pe
rce
nta
ge
Co
ve
r
Grazers present
Grazers absent
south coast
eastcoast
• Consumers
KELP PRODUCTION
KE
LP
C
ON
SU
MP
TIO
N
coralline
world
kelp
world
A B
C D
Case A: consumption is much
higher than production, and small
variation in either has little
impact.
Cases B and C: when
consumption roughly equals
production, small changes in
either can shift the system to a
different state.
Case D: production is much
higher than consumption, and
small variation in either has little
impact.
A continuum
KELP PRODUCTION
KE
LP
C
ON
SU
MP
TIO
N
coralline
world
kelp
world
Eastern Australia
Productivity is high
and varies little, but
large variation in
consumption is driven
by patchy distributions
of urchins (in both
space and time).
KELP PRODUCTION
KE
LP
C
ON
SU
MP
TIO
N
coralline
world
kelp
world
Western & South Australia
Variation in herbivory is
relatively low, but large
variation in productivity is
driven by land use
Policy: long-term benefits?
Global Local Global & Local
Size of Effect
Conceptual summary of experiments
Stressors
Connell (2007) Oxford University Press
Climate
Individuals
Global
Biogeography
Flindersia
Coastal morphology
Gulf
Local conditions
Depth
Per
cen
tag
e co
ver
of
rock
y h
abit
at
Per
cen
tag
e co
ver
of
rock
y h
abit
at
year 2050 (550 ppm)
Per
cen
tag
e co
ver
of
rock
y h
abit
at
....
“Political decisions are empowered by scientific evidence in support of policy initiatives” Steve Kennelly
(Director Fisheries, NSW DPI)
Bring back the kelp
Policy
Environment InstituteScience Seminar Series 2009
Semester 2 Series begins Friday 31 July
Program to be released shortly
www.adelaide.edu.au/environment
