One of the twenty-first century’s greatest environmental challenges is to recover and restore species, habitats and ecosystems. The decision about how to initiate restoration is best-informed by an understanding of the linkages between ecosystem components and, given these linkages, an appreciation of the consequences of choosing to recover one ecosystem component before another. However, it remains difficult to predict how the sequence of species’ recoveries within food webs influences the speed and trajectory of restoration, and what that means for human well-being. Here, we develop theory to consider the ecological and social implications of synchronous versus sequential (species-by-species) recovery in the context of exploited food webs. A dynamical systems model demonstrates that synchronous recovery of predators and prey is almost always more efficient than sequential recovery. Compared with sequential recovery, synchronous recovery can be twice as fast and produce transient fluctuations of much lower amplitude. A predator-first strategy is particularly slow because it counterproductively suppresses prey recovery. An analysis of real-world predator–prey recoveries shows that synchronous and sequential recoveries are similarly common, suggesting that current practices are not ideal. We highlight policy tools that can facilitate swift and steady recovery of ecosystem structure, function and associated services

This paper was authored by Jameal F. Samhouri, Adrian C. Stier (me), Shannon M. Hennessey, Mark Novak, Benjamin S. Halpern & Phillip S. Levin. You can find a copy of the manuscript here, or contact me directly for a PDF. 

Ecosystems often shift abruptly and dramatically between different regimes in response to human or natural disturbances. When ecosystems tip from one regime to another, the suite of available ecosystem benefits changes, impacting the stakeholders who rely on these benefits. These changes often create some groups who stand to incur large losses if an ecosystem returns to a previous regime. When the participation cost in the decision-making process is extremely high, this can “lock in” ecosystem regimes, making it harder for policy and management to shift ecosystems out of what the majority of society views as the undesirable regime. Public stakeholder meetings often have high costs of participation, thus economic theory predicts they will be dominated by extreme views and often lead to decisions that do not represent the majority viewpoint. Such extreme viewpoints can create strong inertia even when there is broad consensus to manage an ecosystem towards a different regime. In the same manner that reinforcing ecological feedback loops make it harder to exit an ecosystem regime, there are decision-making feedback loops that contribute additional inertia.

This paper was authored by Lynham J, Halpern BS, Blenckner T, Essington T, Estes J, Hunsicker M, Kappel C, Salomon AK, Scarborough C, Selkoe KA, and Stier A (me). You can find a copy of the manuscript here, or contact me directly for a PDF. 

Habitat loss, overexploitation, and numerous other stressors have caused global declines in apex predators. This “trophic downgrading” has generated widespread concern because of the fundamental role that apex predators can play in ecosystem functioning, disease regulation, and biodiversity maintenance. In attempts to combat declines, managers have conducted reintroductions, imposed stricter harvest regulations, and implemented protected areas. We suggest that full recovery of viable apex predator populations is currently the exception rather than the rule. We argue that, in addition to well-known considerations, such as continued exploitation and slow life histories, there are several underappreciated factors that complicate predator recoveries. These factors include three challenges. First, a priori identification of the suite of trophic interactions, such as resource limitation and competition that will influence recovery can be difficult. Second, defining and accomplishing predator recovery in the context of a dynamic ecosystem requires an appreciation of the timing of recovery, which can determine the relative density of apex predators and other predators and therefore affect competitive outcomes. Third, successful recovery programs require designing adaptive sequences of management strategies that embrace key environmental and species interactions as they emerge. Consideration of recent research on food web modules, alternative stable states, and community assembly offer important insights for predator recovery efforts and restoration ecology more generally. Foremost among these is the importance of a social-ecological perspective in facilitating a long-lasting predator restoration while avoiding unintended consequences.

This paper was authored by Adrian C. Stier (me), Jameal F. Samhouri, Mark Novak, Kristin N. Marshall, Eric J. Ward, Robert D. Holt, and Phillip S. Levin. You can find a copy of the manuscript here, or contact me directly for a PDF.