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.

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.

Marine legislation is becoming more complex and marine ecosystem-based management is specified in national and regional legislative frameworks. Shelf-seas community and ecosystem models (hereafter termed ecosystem models) are central to the delivery of ecosystem-based management, but there is limited uptake and use of model products by decision makers in Europe and the UK in comparison with other countries. In this study, the challenges to the uptake and use of ecosystem models in support of marine environmental management are assessed using the UK capability as an example. The UK has a broad capability in marine ecosystem modelling, with at least 14 different models that support management, but few examples exist of ecosystem modelling that underpin policy or management decisions. To improve understanding of policy and management issues that can be addressed using ecosystem models, a workshop was convened that brought together advisors, assessors, biologists, social scientists, economists, modellers, statisticians, policy makers, and funders. Some policy requirements were identified that can be addressed without further model development including: attribution of environmental change to underlying drivers, integration of models and observations to develop more efficient monitoring programmes, assessment of indicator performance for different management goals, and the costs and benefit of legislation. Multi-model ensembles are being developed in cases where many models exist, but model structures are very diverse making a standardised approach of combining outputs a significant challenge, and there is a need for new methodologies for describing, analysing, and visualising uncertainties. A stronger link to social and economic systems is needed to increase the range of policy-related questions that can be addressed. It is also important to improve communication between policy and modelling communities so that there is a shared understanding of the strengths and limitations of ecosystem models

Aim: Previous work demonstrated a pronounced geography of synchrony for marine phytoplankton and used that geography to infer statistical environmental determinants of synchrony. Here, we determine whether terrestrial vegetation (measured by the enhanced vegetation index, EVI) also shows a geography of synchrony and we infer determinants of EVI synchrony. As vegetation is the basis of the terrestrial food web, changes in spatio-temporal vegetation dynamics may have major consequences.Location: The land. Results: The first main result is that there is a pronounced and previously unrecognized geography of synchrony for terrestrial vegetation. Some areas, such as the Sahara and Southern Africa, exhibited nearly perfect synchrony, whereas other areas, such as the Pacific coast of South America, showed very little synchrony. Spatial modelling provided the second main result, namely that synchrony in temperature and precipitation were major determinants of synchrony in EVI, supporting the presence of dual global Moran effects. These effects depended on the time-scales on which synchrony was assessed, providing our third main result, namely that synchrony of EVI and its geography are time-scale specific.Main conclusions: To our knowledge, this study is the first to document the geography of synchrony in terrestrial vegetation. We showed that geographical variation in synchrony is pronounced. We used geographical patterns to identify determinants of synchrony. This study is one of very few studies to demonstrate two separate synchronous environmental variables driving synchrony simultaneously. The geography of synchrony is apparently a major phenomenon that has been little explored.

Aim: Spatial synchrony in plankton is imperfectly understood yet may have far-reaching implications, for example for carbon export to the deep ocean. Several techniques have been used to describe patterns of spatial synchrony, from correlation coefficients to spectral methods. Some studies have used temporally extensive data sets to identify causes of synchrony. This study instead uses the exceptional spatial extent provided by remotely sensed data to describe, for the first time as far as we know, geographical patterns of synchrony in marine phytoplankton. We use these patterns to illuminate drivers of synchrony and of its geography.Location: The oceans. Time period: 2003-2015.Major taxon: Chlorophyll a-containing phytoplankton.Methods: Synchrony in chlorophyll a concentrations is mapped globally. Spatial statistics and model selection are used to illuminate main statistical determinants of synchrony and of geographical patterns in synchrony. Results:The first main result is that there is a pronounced and previously unmapped geography of synchrony for phytoplankton. For instance, synchrony was highest in the open ocean, specifically in gyres, and lowest in coastal regions. Spatial modelling provided the second main result that synchrony in sea surface temperature (SST) was a major statistical determinant of chlorophyll synchrony in both the Pacific and Atlantic Oceans, indicating a strong Moran effect, although possibly an indirect and/or complex one. In the Pacific Ocean, this effect depended on the time-scales on which synchrony was assessed, providing our third result, which is that synchrony of phytoplankton and its geography can be time-scale specific. Synchrony of surface solar irradiance was not associated with synchrony of chlorophyll.Main conclusions: To our knowledge, this study is the first to map geography of synchrony in marine plankton. We showed that this geography is pronounced. Geographical patterns illuminated determinants of synchrony. The geography of synchrony is a major phenomenon that has been little explored. K E Y W O R D Scospectrum, Moran effect, phytoplankton, remote sensing, spatial modelling, synchrony