Climate change‐related regime shifts have altered spatial synchrony of plankton dynamics in the North Sea

Abstract

During the 1980s, the North Sea plankton community underwent a well-documented ecosystem regime shift, including both spatial changes (northward species range shifts) and temporal changes (increases in the total abundances of warmer water species). This regime shift has been attributed to climate change. Plankton provide a link between climate and higher trophic-level organisms, which can forage on large spatial and temporal scales. It is therefore important to understand not only whether climate change affects purely spatial or temporal aspects of plankton dynamics, but also whether it affects spatiotemporal aspects such as metapopulation synchrony. If plankton synchrony is altered, higher trophic-level feeding patterns may be modified. A second motivation for investigating changes in synchrony is that the possibility of such alterations has been examined for few organisms, in spite of the fact that synchrony is ubiquitous and of major importance in ecology. This study uses correlation coefficients and spectral analysis to investigate whether synchrony changed between the periods 1959-1980 and 1989-2010. Twenty-three plankton taxa, sea surface temperature (SST), and wind speed were examined. Results revealed that synchrony in SST and plankton was altered. Changes were idiosyncratic, and were not explained by changes in abundance. Changes in the synchrony of Calanus helgolandicus and Para-pseudocalanus spp appeared to be driven by changes in SST synchrony. This study is one of few to document alterations of synchrony and climate-change impacts on synchrony. We discuss why climate-change impacts on synchrony may well be more common and consequential than previously recognized.

Synchrony affects Taylor’s law in theory and data

“…Increasing evidence shows that changing Moran effects, possibly due to climate change, modify synchrony (19,21,(26)(27)(28). This work indicates that changed synchrony will modify the slope and possibly the validity of TL, with ramifications for applications of TL in many areas, including resource management (3), conservation (11), human demography (6), tornado outbreaks (8), and agriculture (2,12,13).…”

“…Understanding the relationship of synchrony with TL is important, because both patterns are widespread in population ecology, and because TL and recent observed climate changeinduced modifications in synchrony have applied importance (19,21,(26)(27)(28).…”

“…Synchrony, like TL, may reflect aggregation, because the spatial extent of correlations among population time series indicates the geographic size of outbreaks (26). Engen,et al (25) connected TL with synchrony theoretically but did not use spatial or temporal TL.…”

“…Large-scale climatic changes in the North Atlantic Oscillation caused changes in winter temperature synchrony, which in turn caused changes in the synchrony of pest aphid species in the United Kingdom (27). Changes in the synchrony of plankton (26) and tree rings (28) have been associated with climate change. If synchrony influences TL,…”

Quantifying the contribution of sea lice from aquaculture to declining annual returns in a wild Atlantic salmon population

“…The negative impact of sea lice on salmonid survival appears to be exacerbated by warmer environmental conditions (Bateman et al 2016, Shephard et al 2016). In the ocean, salmon respond to large-scale climate forcing (ICES 2016) by the North Atlantic Oscillation (NAO) and the At lantic Multi-decadal Oscillation (AMO) that drive sea surface temperature (SST) and thus salmon thermal habitat (Friedland et al 1993, 2003, Jonsson & Jonsson 2004, Mills et al 2013) and asso ciated prey dynamics (Beaugrand & Reid 2012, Defriez et al 2016. Recent studies suggest that ocean warming has had a negative impact on oceanic growth and survival (McCarthy et al 2008, Todd et al 2008, Friedland et al 2009) and genetic diversity (Horreo et al 2011) of Atlantic salmon.…”