Landscape-scale approaches are emerging as central to ecosystem management and biodiversity conservation globally, triggering the requirement for collaboration between multiple actors and associated risks including knowledge asymmetries; institutional fragmentation; uncertainty; power imbalances; “invisible” slow-changing variables; and entrenched socio-economic inequities. While social science has elucidated some dimensions required for effective collaboration, little is known about how collaboration manages these risks, or of its effects on associated social-ecological linkages. Our analysis of four different Australian contexts of collaboration shows they mobilised institutions matched to addressing environmental threats, at diverse scales across regulatory and non-regulatory domains. The institutions mobilised included national regulatory controls on development that threatened habitat, incentives to farmers for practice-change, and mechanisms that increased resources for on-ground fire and pest management. Knowledge-sharing underpinned effective risk management and was facilitated through the use of boundary objects, enhanced multi-stakeholder peer review processes, interactive spatial platforms, and Aboriginal-driven planning. Institutions mobilised in these collaborations show scale-dependent comparative advantage for addressing environmental threats. The findings confirm the need to shift scientific attention away from theorising about the ideal-scale for governance. We argue instead for a focus on understanding how knowledge-sharing activities across multiple scales can more effectively connect environmental threats with the most capable institution to address these threats.