- Regime shifts in marine environments
- Fisheries collapse
- Mangroves collapse
- Coral transitions
- Coastal eutrophication
- Hypoxia

- Potential impacts on society
- ~50M people depend on small-scale fisheries
- Mostly in developing countries

Juan Rocha, Caroline Schill, Lina M Saavedra, Rocio Moreno, & Jorge H Maldonado

Regime shifts are large, abrupt and persistence critical transitions in the function and structure of (eco)systems

Regime shifts are large, abrupt and persistence critical transitions in the function and structure of (eco)systems

- Regime shifts in marine environments
- Fisheries collapse
- Mangroves collapse
- Coral transitions
- Coastal eutrophication
- Hypoxia

- Potential impacts on society
- ~50M people depend on small-scale fisheries
- Mostly in developing countries

- Previous research:
- WEIRD people
- Lab experiments

- Predicts negative relationship between uncertainty and cooperation
- CPR games: static and dynamic games shows uncertainty \(\downarrow\) cooperation
- Public good games: threshold impact and location uncertainty \(\downarrow\) cooperation
- Critical role of communication

- 256 participants from 4 fishing communities
- Largely depend on natural resources as main source of income
- History of regime shifts:
- Mangroves collapse (1980s -90s)
- Hypoxia events and fish deadzones

- 256 fishers groups of 4 players
- Communication allowed
- Threshod: 100% probability of climate event
- Risk: 50% probability
- Uncertainty: 10-90% probability

- Individual extraction: \[x_{i,t}\]
- Proportion of extraction: \[x_{i,t}/S_t\]
Cooperation: \[C_{i,t} = \frac{x_{i,t}}{\frac{S_t - \theta}{N}}\]

Diff-in-diff regression: \[\hat{Y_i} = \hat{\mu} + \hat{\gamma}G_i + \hat{\delta}T_i + \hat{\tau}G_iT_i\]

It’s harder to coordinate under treatments, but agreements increase the probability to coordinate and react to lower stock sizes by reducing fishing preasure. Agreements also reduce the variance of extraction and the variance of cooperation. **Changes in fishing effort depends on treatments while changes in cooperation depends on context.**

- Fishermen facing thresholds fish less – they take care of the resources
- By reducing fishing effort or keeping close to the social optimal people do cooperate. However, cooperation by itself is not affected by our treatments, it seems to be driven more by personal and group dynamics.
- If the existence of threshold effects already triggers cooperative behavior in natural resource users, then communicating their potential effects on ecosystems and society is more important that quantifying the precise point at which ecosystems tip over. Specially because such thresholds are hard to observe, measure, and they change over time.

Questions?

email: juan.rocha@su.se

twitter: @juanrocha

slides: juanrocha.se

paper: Preprint coming soon!

Stockholm Resilience Centre

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