Identifying regime shifts, transients and late warning signals for proactive ecosystem management

Abstract

Conservation Biology fosters the study of Earth's ecosystems and biodiversity aiming at protecting species and their habitats from menaces causing the erosion of biotic interactions and extinctions. Its ultimate goal is to preserve biodiversity and promote sustainable ecological management maintaining both ecosystem's resilience and services. Ecosystems display complex patterns in time and space due to the intrinsic nonlinear nature of their interactions and can suffer regime shifts driven by the agents of global change. During the last decades, Ecology has turned from the equilibrium metaphor to the paradigm of non-equilibrium dynamics. This involves putting into the scene multiple stable states, nonlinear regime shifts, stochasticity, and ecological transients. These aspects are also crucial for biological conservation since they play a fundamental role in species' persistence, ecosystems' resilience, and in detecting warning signals prior to either the collapse or the recovery of the ecosystem. In this contribution, we discuss ecological regime shifts caused by tipping points in real ecosystems. Then, we provide information on some known dynamical features from theoretical ecology and dynamical systems theory associated to tipping points, mainly given by transient phenomena and the characteristic statistical patterns tied to early warning signals. These features are illustrated with a single-species mathematical model including facilitation and immigration. We also introduce and provide evidence of late warning signals as a way to identify when a tipping point has been surpassed but the system still remains in a transient state and recovery may be still possible. Our main goal is to near non-equilibrium concepts in Ecology to the conservationist community and promote bridges between such concepts and the management and conservation of ecosystems.