ecology, evolution, and game theory at iiasa: overview ... · game theory at iiasa: overview &...
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Ecology, Evolution, and Game Theory at IIASA: Overview & Highlights Ulf Dieckmann Program Director Evolution and Ecology Program
Early Highlights in Ecology
Resilience dynamics
Pest management models Adaptive management
Early Highlights in Game Theory Game theory, decision analysis Indirect reciprocity
Replicator dynamics Win-stay, lose-shift Adaptive dynamics
Methodological integration
Interdisciplinary Bridges
Anthropogenic environmental impacts
Evolution Ecology Socio- economics
on fisheries, biodiversity, common goods, …
Ecology: Recent Highlights
Management measures
Socio-economic system
Processors and retailers
Fishers
Consumers
Socio-economic environment
Fishery Systems Management system
Fishery policy and planning
Fishery management
Fishery development
Fishery research
Service values
Fishing pressure
Ecosystem status
Ecosystem services Supporting services
Regulating services
Provisioning services
Cultural services
Natural system Target stock
Non-target species
Ecosystem embedding
Physical environment
Management of Northeast Arctic Cod
Adult biomass (1000 tonnes)
Marine Policy 39:172 (2013)
• Challenge Harvest-control rules are politically negotiated without support from quantitative modeling
• Innovation Our assessment is process-based, couples an individual-based biological model with an economic model, and accounts for three alternative objectives
• Results Current rule maximizes profit, while alternative objectives lead to more aggressive exploitation
Yield-maximizing HCR (Johannesburg World Summit 2002)
Welfare-maximizing HCR Current HCR Profit-maximizing HCR
0 20 40 60 80 100 Mi
nim
um-s
ize lim
it (c
m)
Annual harvest proportion of unprotected stock (%)
5
10
15
2
0
Status quo
70%
Management of Barents Sea Capelin • Challenge Traditional
assessments account for quotas, yields, and a single stakeholder group
• Innovation Our assessment accounts for two regulations (quotas and minimum-size limits), four benefits (yields, profits, employment, and ecological impact), and five stakeholder groups
• Results Maximum joint satisfaction is high, and is best achieved through minimum-size limits
Evolution: Recent Highlights
• Challenge Stock collapsed in 1992 and has not recovered since; heavy exploitation favors earlier maturation at smaller size
• Innovation Pioneering statistical and modeling techniques
• Results We have documented a 30% drop in size at maturation and showed that such evolutionary impacts of fishing are very slow and difficult to reverse
Collapse of Northern Cod
Moratorium
1975 1992 2004 30
80
70
60
50
40
Size at 50% maturation probability at age 5 (cm)
Nature 428:932 (2004)
Improving Fishing Policies • Challenge Evolutionary
considerations are a blind spot of current fisheries management
• Innovation Convened international expert group on Fisheries-induced Evolution as part of the scientific advice by the International Council for the Exploration of the Sea (ICES)
• Results Monitoring maturation evolution has become a binding EU requirement; new tool: Evolutionary Impact Assessments (EvoIAs)
Science 318:1247 (2007) Science 320:48 (2008)
A New Understanding of Biodiversity • Challenge Factors
maintaining biodiversity are poorly understood
• Innovation New model accounting for spatial structure and partner choice
• Results Correction of a textbook error: biodiversity can be maintained without ecological differentiation Nature 484:506 (2012)
Calibrated Stream Ecosystem Models
• Challenge Causal processes underlying biodiversity patterns need to be understood
• Innovation New process-based and empirically calibrated model of biodiversity in stream ecosystems
• Results Patterns observed in unpolluted rivers are recovered; responses to pollution can be predicted
Polluted rivers
Unpolluted rivers
Log
rela
tive
abun
danc
e
Species rank
1
10-3
10-1
10-2
1
10-3
10-1
10-2
1 10 30 20
Game Theory: Recent Highlights
Global climate Demography
Urbanization Social security
Living resources Land use
Social Dilemmas & Common Goods • Challenge Many common
goods are under the threat of selfish actors (such as individuals, companies, governments)
• Innovations IIASA’s work is overcoming key limitations of current cooperation models:
• Wealth inequality • Institutional sanctioning • Mixed incentives
Without wealth inequality With wealth inequality
A few rich cooperators suffice to enable cooperation under adverse conditions
Blue: cooperators, red: defectors, bright: rich sites, dark: poor sites
Effects of Wealth Inequality
4:2453 (2013)
Penalties with an Exit Option
109:1165 (2012)
Mixed Incentives • Challenges Game-theoretical analyses of incentives have focused on peer-to-peer interactions; positive and negative incentives are mostly studied in separation
• Innovation We show how institutional positive and negative incentives are best combined
• Results “First carrot, then stick” incentive policy is not only most effective, but also most efficient (cost saving) 12:20140935 (2014)
Interdisciplinary Bridges
Anthropogenic environmental impacts
Evolution Ecology Socio- economics
on fisheries, biodiversity, common goods, …
Two cross-cutting projects on systemic risk and equitable governance