Cascading regime shifts within and across scales

Regime shifts are large, abrupt, and persistent critical transitions in the function and structure of ecosystems. Yet, it is unknown how these transitions will interact, whether the occurrence of one will increase the likelihood of another or simply correlate at distant places. We explored two types of cascading effects: Domino effects create one-way dependencies, whereas hidden feedbacks produce two-way interactions. We compare them with the control case of driver sharing, which can induce correlations. Using 30 regime shifts described as networks, we show that 45% of regime shift pairwise combinations present at least one plausible structural interdependence. The likelihood of cascading effects depends on cross-scale interactions but differs for each type. Management of regime shifts should account for potential connections.

Cascading regime shifts within and across scales

Regime shifts are large, abrupt and persistent critical transitions in the function and structure of systems (1, 2). Yet it is largely unknown how these transitions will interact, whether the occurrence of one will increase the likelihood of another, or simply correlate at distant places. Here we explore two types of cascading effects: domino effects create one-way dependencies, while hidden feedbacks produce two-way interactions; and compare them with the control case of driver sharing which can induce correlations. Using 30 regime shifts described as networks, we show that 45% of the pair-wise combinations of regime shifts present at least one plausible structural interdependence. Driver sharing is more common in aquatic systems, while hidden feedbacks are more commonly found in terrestrial and Earth systems tipping points. The likelihood of cascading effects depends on cross-scale interactions, but differs for each cascading effect type. Regime shifts should not be studied in isolation: instead, methods and data collection should account for potential teleconnections.

Beyond Actorness

This paper is concerned with the determining factors of the interregional relationship between the European Union (EU) and the Association of Southeast Asian Nations (ASEAN), specifically its institutional proliferation on the three institutional levels of EU-to-ASEAN relations (bi-regionalism), relations inside ASEM (trans-regionalism) as well as relations between the EU and individual ASEAN member states (region-to-state). Commonly, interregional relations are seen as depending on the actorness of the regional organisations involved. This paper proposes an alternative approach, focusing on structural interdependence and agency on the part of both regional actors as the two main determinants of the institutional proliferation. The analysis suggests that levels of political and economic interdependence are low at the bi-regional level and higher at both the trans-regional and region-to-state level, leading to a proliferation of institutional structures at these levels. Additionally, the analysis reveals three unique strategies by ASEAN and the EU contributing to the design of their interregional relationship. For ASEAN, these strategies consist of (1) omni-enmeshment, (2) vertical and horizontal hedging, and (3) the rule of relative institutionalisation. For the EU, these strategies consist of (1) a pragmatic approach towards ASEAN, (2) a widening of interest towards East Asia, and (3) capacity-building bi-regionalism.