## Outline

1. Cascading regime shifts within and across scales

1. How do people behave when facing thresholds

## Forest to savanna

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

## Coral transitions

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

## Human-centered operational definition:

Large, persistent (and usually abrupt) shifts in the set of ecosystem services produced by a SES” —Oonsie Biggs

Abruptness affects the capacity to adapt to changes

## Cascading regime shifts within and across scales

Juan C. Rocha, Garry Peterson, Örjan Bodin & Simon Levin

Science. 362, 1379–1383 (2018)

## How regime shifts will interact?

Whether the occurrence of one will increase the likelihood of another, or simply correlate at distant places

## How regime shifts will interact?

Whether the occurrence of one will increase the likelihood of another, or simply correlate at distant places

## Hypotheses

~45% of the regime shift couplings analyzed present structural dependencies in the form of one-way interactions for the domino effect or two-way interactions for hidden feedbacks

## Driver sharing

Aquatic regime shifts tend to have and share more drivers. The most co-occurring drivers are related to food production, climate change & urbanisation. 36% of pair-wise combinations are solely coupled by sharing drivers

## Domino effects

Evidence of cross-scale interactions for domino effects was only found in space but not in time. The maximum number of pathways found was 4, and the variables that produce most domino effects relate to climate, nutrients and water transport

## Hidden feedbacks

Most hidden feedbacks occur in terrestrial and earth systems. Key variables that belong to many of these hidden feedbacks are related to climate, fires, erosion, agriculture and urbanisation

## Conclusions

• How a regime shift somewhere in the world could affect the occurrence of another regime shift remains an open question and a key frontier of research.
• Developed network-based method that allow us to explore plausible cascading effects and distinguish potential correlations from true interdependencies.
• Regime shifts can be interconnected: they should not be study in isolation assuming they are independent systems. Methods and data collection that takes into account the possibility of cascading effects needs to be further developed.
• The frequency and diversity of regime shifts interconnections suggests that current approaches to environmental management and governance are substantially underestimating the likelihood of cascading effects.

## Criticism: plausible vs. probable

“…the use of qualitative information inevitably has limitations […] it can only provide a catalog of the possible”

A case study on salmon

Juan C. Rocha & Jessica Gephart

Stockholm Resilience Centre

## Telecoupling and teleconnections

“human actions in one place may create unintended consequences elsewhere”

• By 2016 salmon trade accounted for 11.6B US\$:
• 93 countries
• 406 bilateral relationships
• In 2016 toxic algae bloom “red tide” killed 20% of Chile’s salmon:
• 27M salmon = 70M pounds
• >300 whales
• 40k tons sardines
• >800M dollars lost

## Method: convergent cross-mapping

Each link correspond to the relationship A -> B <- C, where the forecasting skill allow us to predict C dynamics given the time series of A with a rho > 0.1 (t-test, p < 0.05)

Salmon fisheries around the world are tightly connected, the dynamics of a country production can easily influence fishing efforts in far away ecosystems [Teleconnections!]

Each link correspond to the relationship A -> B <- C, where the forecasting skill allow us to predict C dynamics given the time series of A with a rho > 0.1 (t-test, p < 0.05)

Salmon fisheries around the world are tightly connected, the dynamics of a country production can easily influence fishing efforts in far away ecosystems [Teleconnections!]

41 out of 239 trading countries are causally related on the salmon trade network (~45%)

Prediction skill $$\rho$$ is weakly correlated to network structure but not necessarily with trade volume

## Lessons

• It is possible to detect interdependencies between natural resource exploitation in far way places = teleconnections
• Non-linear causality detection techniques help to identify relevant links on the network; relevant for management
• Governance of natural resources transcends national borders, but it’s important to know with whom to team up to better manage ecosystems

## How do people behave when facing thresholds?

Rocha, J; Schill, C; Saavedra, LM; Moreno, R; Maldonado, JH

## History of regime shifts

People do coordinate less under risk treatment, but they reach better agreements under uncertainty by reducing their variance. Higher levels of cooperation are related to higher levels of education and lower income in bad fishing days

## Lessons

• Fishermen facing thresholds fish less – they take care of the resources
• Higher resource dependence and higher education increase cooperation
• If cooperation increases in the face of thresholds, then communicating uncertainty is more policy relevant than estimating precisely where tipping points lay in social-ecological systems.

• How regime shifts can be interconnected?
• How regime shifts can be interconnected?
• Can we empirically detect cascading effects?
• How regime shifts can be interconnected?
• Can we empirically detect cascading effects?
• How do people behave when facing thresholds?

## Gracias | Tack

Questions?

email: juan.rocha@su.se