Unifying sources and sinks in ecology and Earth sciences

• Published in: Biological reviews of the Cambridge Philosophical Society Vol. 88; no. 2; pp. 365 - 379
• Main Authors: Loreau, Michel, Daufresne, Tanguy, Gonzalez, Andrew, Gravel, Dominique, Guichard, Frédéric, Leroux, Shawn J., Loeuille, Nicolas, Massol, François, Mouquet, Nicolas
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.05.2013; Wiley
• Subjects: Animals; Biological Evolution; Conservation; Conservation of Natural Resources; Earth science; Earth sciences; ecology; Ecosystem; Ecosystem conservation; Ecosystem services; Ecosystems; Evolution; Life Sciences; Models, Theoretical; sink; Sinkholes; source; Source-sink relationships; EVOLUTIONARY RESCUE; earth sciences; sink; ENVIRONMENTAL FLUCTUATIONS; evolution; source; HABITAT SELECTION; conservation; SPATIAL HETEROGENEITY; ecology; PLANT-COMMUNITIES; CARBON EXCHANGE; ecosystems; HETEROGENEOUS LANDSCAPE; META-ECOSYSTEMS; POPULATION-DYNAMICS; PREVENT EXTINCTION
• ISSN: 1464-7931; 1469-185X; 1469-185X
• DOI: 10.1111/brv.12003

ABSTRACT The paired source and sink concepts are used increasingly in ecology and Earth sciences, but they have evolved in divergent directions, hampering communication across disciplines. We propose a conceptual framework that unifies existing definitions, and review their most significant consequences for the various disciplines. A general definition of the source and sink concepts that transcends disciplines is based on net flows between the components of a system: a source is a subsystem that is a net exporter of some living or non‐living entities of interest, and a sink is a net importer of these entities. Sources and sinks can further be classified as conditional and unconditional, depending on the intrinsic propensity of subsystems to either produce (source) or absorb (sink) a surplus of these entities under some (conditional) or all (unconditional) conditions. The distinction between conditional and unconditional sources and sinks, however, is strongly context dependent. Sources can turn into sinks, and vice versa, when the context is changed, when systems are subject to temporal fluctuations or evolution, or when they are considered at different spatial and temporal scales. The conservation of ecosystem services requires careful consideration of the source−sink dynamics of multiple ecosystem components. Our synthesis shows that source−sink dynamics has profound consequences for our ability to understand, predict, and manage species and ecosystems in heterogeneous landscapes.