In the discussion of the existence and avoidance of tipping points between desirable and undesirable states, e.g. the transgression from a clear water lake to a turbid one, the interpretation of alternative stable states undergoing a regime shift is usually dominating in those studies. Inspired by a Swedish case of shallow lake restoration, we instead looked into trajectories for restoring a clear water state from a previously turbid lake. We simulated different timings of a restoration policy and two social interventions to support policy implementation. Delays in the design of the policy and its implementation affect the nutrient leakage into the lake from private sewage water treatment. Our results show how delays in policy making can up to a degree be compensated by accelerating policy implementation, but also that the total lake restoration time is often more dependent on the time lag in policy making. The study highlights the importance of considering transient dynamics, which is the time that the ecosystem is in transition between alternative states. This transition matters because the strengths of ecological feedbacks of the desired or undesired regime change over time. This influences how societal actions such as reduction in nutrient inflows affect ecological dynamics.

LimnoSES conceptual sketch of policy making, implementation and reinforcements, and ecological causal loops (Martin et al. 2020).

Design of experiments to evaluate transient dynamics with time lags between alternative stable states in a shallow lake (Martin et al. 2020).

Simulated trajectories of shallow lake restoration with different policy time lags (Martin et al. 2020).

If you want to learn more about the analysis of transient, social-ecological dynamics, and how considering transitions and time lags can be more relevant than solely tipping points, we invite you to read our open access PNAS paper and the recent news article. We all might need more stories about restoration of ecosystems and social-ecological systems happening now than collapses in the near future.

Sources:

• The publication: Martin, Romina, Maja Schlüter, and Thorsten Blenckner. 2020. “The Importance of Transient Social Dynamics for Restoring Ecosystems beyond Ecological Tipping Points.” Proceedings of the National Academy of Sciences 117 (5): 2717–22. https://doi.org/10.1073/pnas.1817154117.
• The news at stockholmresilience.org
• The model behind: LimnoSES – [ComSES, bitbucket]
• The projects during which this paper was developed: LimnoTip (2013-2015), Aquacross (2015-2018), LimnScenES (2019-2021), SESlink (2012-2017) and MuSES (2017-2021).