ecology, evolution, and game theory at iiasa: overview ... · game theory at iiasa: overview &...

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