Slow treatment promotes control of harmful species by multiple agents

Adam Lampert,Alan Hastings,James N Sanchirico

doi:10.1111/conl.12568

Adam Lampert, Alan Hastings + Show 1 more

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https://doi.org/10.1111/conl.12568

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Abstract

AbstractThe management of harmful species, including invasive species, pests, parasites, and diseases, is a major, global challenge. Harmful species cause severe damage to ecosystems, biodiversity, agriculture, and human health. The control of harmful species is challenging and often requires cooperation among multiple agents, such as land‐owners, agencies, and countries. Agents may have incentives to contribute less, leaving more work for other agents, which can result in inefficient treatment. Here we present a dynamic game theory model and we show that slow treatment may promote a stable solution (Markovian Nash equilibrium) where all agents cooperate to remove the harmful species. The efficiency of this solution depends critically on the life history of the harmful species that determines the speed of optimal treatment. Furthermore, this cooperative equilibrium may coexist with other Nash equilibria, including one dictating no treatment of the harmful species, which implies that coordination among agents is critical for successful control.

Highlights

Harmful species, among which are invasive species, pathogens and various pests, threaten ecosystems worldwide and are a major cause of biodiversity loss
Under certain conditions, there exist Markovian Nash equilibria where multiple agents simultaneously remove the harmful species (Figure 2 and Theorem 1)
The first condition, Equation (S1), implies that the harmful species population either does not decline or is slow to decline naturally. (Otherwise, agents will not contribute since recovery proceeds rapidly enough without intervention (Lampert & Hastings, 2014).) The second condition, Equation (S2), implies that the cost to a given contributing agent due to the pest, Ci, is not much lower than that cost to the other agents

Summary

Introduction

Among which are invasive species, pathogens and various pests, threaten ecosystems worldwide and are a major cause of biodiversity loss. The aggregate contribution to harmful species eradication by a group of agents is likely to be less than that made by a single manager in the same system. We address the basic question of whether and under what conditions a group of agents will be more likely to voluntarily cooperate (i.e., without the need for enforcement) to eradicate and/or control a harmful species (or, more broadly, restore ecosystems).

Results

Conclusion