Synchrony is more than its top-down and climatic parts: Interacting Moran effects on phytoplankton in British seas

This work is licensed under a Creative Commons Attribution 4.0 International License. Large-scale spatial synchrony is ubiquitous in ecology. We examined 56 years of data representing chlorophyll density in 26 areas in British seas monitored by the Continuous Plankton Recorder survey. We used wavele...

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Bibliographic Details
Published in:PLOS Computational Biology
Main Authors: Sheppard, Lawrence W., Defriez, Emma J., Reid, Philip C., Reuman, Daniel C.
Format: Article in Journal/Newspaper
Language:unknown
Published: Public Library of Science 2020
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Online Access:http://hdl.handle.net/1808/30909
https://doi.org/10.1371/journal.pcbi.1006744
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Summary:This work is licensed under a Creative Commons Attribution 4.0 International License. Large-scale spatial synchrony is ubiquitous in ecology. We examined 56 years of data representing chlorophyll density in 26 areas in British seas monitored by the Continuous Plankton Recorder survey. We used wavelet methods to disaggregate synchronous fluctuations by timescale and determine that drivers of synchrony include both biotic and abiotic variables. We tested these drivers for statistical significance by comparison with spatially synchronous surrogate data. Identification of causes of synchrony is distinct from, and goes beyond, determining drivers of local population dynamics. We generated timescale-specific models, accounting for 61% of long-timescale (> 4yrs) synchrony in a chlorophyll density index, but only 3% of observed short-timescale (< 4yrs) synchrony. Thus synchrony and its causes are timescale-specific. The dominant source of long-timescale chlorophyll synchrony was closely related to sea surface temperature, through a climatic Moran effect, though likely via complex oceanographic mechanisms. The top-down action of Calanus finmarchicus predation enhances this environmental synchronising mechanism and interacts with it non-additively to produce more long-timescale synchrony than top-down and climatic drivers would produce independently. Our principal result is therefore a demonstration of interaction effects between Moran drivers of synchrony, a new mechanism for synchrony that may influence many ecosystems at large spatial scales. UK Natural Environment Research Council grant NE/H020705/1 UK Natural Environment Research Council grant NE/I010963/1 UK Natural Environment Research Council grant NE/I011889/1 James S McDonnell Foundation US National Science Foundation grant 1442595 US National Science Foundation grant 1714195 University of Kansas US National Science Foundation grant 1225529