Science Seminar Series 12 Sean Connell

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

is playing an increasing role:  funded and published  how data are acquired and interpreted

In a race for $ and the headlines needed to lobby $... “Since the Jamaica story was an anomaly, it makes a poor foundation for general models of reef ecology” Bruno et al. 2009 Ecology

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 5. Contingencies via climate an immersion of science

#1. Baseline N Australia Adelaide Urban 1 South Australia Agricultural 1 Victor Harbor Urban 2 Adelaide Natural 2 Agricultural 2 Natural 1 25 km South North Sites

#1. Baseline Cape Leeuwin Encounter Bay

#1. Baseline

# 2. Causes

# 2. Causes 0.80 Heavy rainfall 0.40 Light rainfall Mean NOx conc. light rainfall (mg L-1) 0.60 0.30 Mean NOx conc. heavy (mg L-1) 0.40 0.20 0.20 0.10 0.00 0.00 Urban Agricultural Natural Catchment type

# 2. Causes 20 Urban Agricultural Natural Canopy-formers mean: 5.9 mean: 9.5 mean: 11.4 PATCH-SIZE FREQUENCY 10 0 20 Turf-formers mean: 4.1 mean: 3.4 mean: 2.3 10 0 0 10 20 30 0 10 20 30 0 10 20 30 40 Diameter of habitat patches (m)

# 2. Causes 0 Urban Agricultural Natural 12 uptake of urban derived nitrogen (b) 10 δ15N (‰  SE) Urban 8 6 Natural Agricultural 4 -22 -21 -20 -19 δ13C (‰  SE)

# 2. Mechanisms

# 2. Mechanisms Ambient Nutrients 100 Elevated Nutrients Percentage cover of turf 80 60 40 20 0 Summer Winter Summer Winter Natural catchment Urban catchment

# 3. Restoration Non-removal control Turf removal 100 80 Recovery (%) 60 40 20 0 1 2 3 Turf-dominated sites

#4. Contingencies Contingencies Production & consumption via humans & biogeography

#4. Contingencies • Oceanography Bigger cities = bigger impacts? Sydney Environmental Impact Perth Adelaide Human population

• Oceanography Western Australia 20 Southern Australia % cover of turf Sydney Eastern Australia 10 0 0 0.5 1.0 1.5 Chlorophyll a 20 Chlorophylla (mg l-1) 15 10 5 Sydney 0 Southern Eastern 0.3 insitu sampling at depth of subtidal habitats NOx (Milligrams/l) 0.2 0.1 Sydney 0.0 a b a b Southern Eastern

• Oceanography 25 Ambient Enriched 7.25 % 20 49.64% Turfs (% cover) 15 1000 Km 10 5 0 south east coast coast Cape Jervis

6000 Productivity 5000 SE Alaska 4000 Japan 3000 Norway Central California S Chile Southern California 2000 S Africa-South Coast Gulf of Maine East Australia 1000 South & West Australia 2 4 6 8 10 12 14 Integrated Monthly NO3 Flux

The poster child easy ecology

• Consumers

Data courtesy of Nick Shears 75 % (n = 113 sites) have no barrens

70 % (n = 60 sites) have no barrens

• Consumers 100 Grazers present 80 Grazers absent Percentage Cover 60 1000 Km 40 20 0 south east coast coast Cape Jervis

A continuum Case A: consumption is much coralline A B KELP CONSUMPTION higher than production, and small variation in either has little world 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 C D higher than consumption, and small variation in either has little kelp impact. world KELP PRODUCTION

coralline world KELP CONSUMPTION 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 world KELP PRODUCTION

coralline world KELP CONSUMPTION Western & South Australia Variation in herbivory is relatively low, but large variation in productivity is driven by land use kelp world KELP PRODUCTION

Policy: long-term benefits?

Conceptual summary of experiments Size of Effect Global Local Global & Local Stressors

Connell (2007) Oxford University Press

Climate Global Flindersia Biogeography Gulf Coastal morphology Depth Local conditions Individuals

Percentage cover of rocky habitat

Percentage cover of rocky habitat year 2050 (550 ppm)

Percentage cover of rocky habitat

“Political decisions are empowered by scientific evidence in support of policy initiatives” Steve Kennelly (Director Fisheries, NSW DPI) ....

Bring back the kelp

Policy

Environment Institute Science Seminar Series 2009 Semester 2 Series begins Friday 31 July Program to be released shortly www.adelaide.edu.au/environment

Science Seminar Series 12 Sean Connell

by University of Adelaide

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