%0 Journal Article %J Science Advances %D 2019 %T Atlantic Multidecadal Oscillations drive the basin-scale distribution of Atlantic bluefin tuna %A Robin Faillettaz %A Grégory Beaugrand %A Goberville, Eric %A Richard R Kirby %X

The Atlantic bluefin tuna (hereafter referred to as “bluefin tuna”), one of the world's most valuable and exploited fish species, has been declining in abundance throughout the Atlantic from the 1960s until the mid-2000s. Following the establishment of drastic management measures, the stock has started to recover recently and, as a result, stakeholders have raised catch quotas by 50{%} for the period 2017–2020. However, stock assessments still omit the natural, long-term variability in the species distribution. Here, we explore the century-scale fluctuations in bluefin tuna abundance and distribution to demonstrate a prevailing influence of the Atlantic Multidecadal Oscillation (AMO) to provide new insights into both the collapse of the Nordic bluefin tuna fishery circa 1963 and the recent increase in bluefin tuna abundance in the Northeast Atlantic. Our results demonstrate how climatic variability can modulate the distribution of a large migrating species to generate rapid changes in its regional abundance, and we argue that climatic variability must not be overlooked in stock management plans for effective conservation.

%B Science Advances %V 5 %P eaar6993 %G eng %R 10.1126/sciadv.aar6993 %0 Journal Article %J Nature Climate Change %D 2019 %T Prediction of unprecedented biological shifts in the global ocean %A Grégory Beaugrand %A Alessandra Conversi %A Angus Atkinson %A Jim E. Cloern %A Sanae Chiba %A Serena Fonda-Umani %A Richard R Kirby %A Greene, C. H. %A Goberville, Eric %A Otto, S. A. %A Philip Chris Reid %A Stemmann, L. %A Martin Edwards %X

Impermanence is an ecological principle1 but there are times when changes occur nonlinearly as abrupt community shifts (ACSs) that transform the ecosystem state and the goods and services it provides2. Here, we present a model based on niche theory3 to explain and predict ACSs at the global scale. We test our model using 14 multi-decadal time series of marine metazoans from zooplankton to fish, spanning all latitudes and the shelf to the open ocean. Predicted and observed fluctuations correspond, with both identifying ACSs at the end of the 1980s4,5,6,7 and 1990s5,8. We show that these ACSs coincide with changes in climate that alter local thermal regimes, which in turn interact with the thermal niche of species to trigger long-term and sometimes abrupt shifts at the community level. A large-scale ACS is predicted after 2014—unprecedented in magnitude and extent—coinciding with a strong El Niño event and major shifts in Northern Hemisphere climate. Our results underline the sensitivity of the Arctic Ocean, where unprecedented melting may reorganize biological communities5,9, and suggest an increase in the size and consequences of ACS events in a warming world.

%B Nature Climate Change %V 9 %P 237–243 %8 mar %G eng %U http://www.nature.com/articles/s41558-019-0420-1 %R 10.1038/s41558-019-0420-1 %0 Journal Article %J PLoS ONE %D 2018 %T Marine biodiversity and the chessboard of life %A Grégory Beaugrand %A Christophe Luczak %A Goberville, Eric %A Richard R Kirby %X

© 2018 Beaugrand et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Species richness is greater in places where the number of potential niches is high. Consequently, the niche may be fundamental for understanding the arrangement of life and especially, the establishment and maintenance of the well-known Latitudinal Biodiversity Gradient (LBG). However, not all potential niches may be occupied fully in a habitat, as measured by niche vacancy/saturation. Here, we theoretically reconstruct oceanic biodiversity and analyse modeled and observed data together to examine patterns in niche saturation (i.e. the ratio between observed and theoretical biodiversity of a given taxon) for several taxonomic groups. Our results led us to hypothesize that the arrangement of marine life is constrained by the distribution of the maximal number of species' niches available, which represents a fundamental mathematical limit to the number of species that can co-exist locally. We liken this arrangement to a type of chessboard where each square on the board is a geographic area, itself comprising a distinct number of sub-squares (species' niches). Each sub-square on the chessboard can accept a unique species of a given ecological guild, whose occurrence is determined by speciation/extinction. Because of the interaction between the thermal niche and changes in temperature, our study shows that the chessboard has more sub-squares at mid-latitudes and we suggest that many clades should exhibit a LBG because their probability of emergence should be higher in the tropics where more niches are available. Our work reveals that each taxonomic group has its own unique chessboard and that global niche saturation increases when organismal complexity decreases. As a result, the mathematical influence of the chessboard is likely to be more prominent for taxonomic groups with low (e.g. plankton) than great (e.g. mammals) biocomplexity. Our study therefore reveals the complex interplay between a fundamental mathematical constraint on biodiversity resulting from the interaction between the species' ecological niche and fluctuations in the environmental regime (here, temperature), which has a predictable component and a stochastic-like biological influence (diversification rates, origination and clade age) that may alter or blur the former.

%B PLoS ONE %V 13 %G eng %R 10.1371/journal.pone.0194006 %0 Journal Article %J Scientific Reports %D 2016 %T Climate change and the ash dieback crisis %A Goberville, Eric %A Nina-Coralie Hautekèete %A Richard R Kirby %A Yves Piquot %A Christophe Luczak %A Grégory Beaugrand %X

© The Author(s) 2016. Beyond the direct influence of climate change on species distribution and phenology, indirect effects may also arise from perturbations in species interactions. Infectious diseases are strong biotic forces that can precipitate population declines and lead to biodiversity loss. It has been shown in forest ecosystems worldwide that at least 10{%} of trees are vulnerable to extinction and pathogens are increasingly implicated. In Europe, the emerging ash dieback disease caused by the fungus Hymenoscyphus fraxineus, commonly called Chalara fraxinea, is causing a severe mortality of common ash trees (Fraxinus excelsior); this is raising concerns for the persistence of this widespread tree, which is both a key component of forest ecosystems and economically important for timber production. Here, we show how the pathogen and climate change may interact to affect the future spatial distribution of the common ash. Using two presence-only models, seven General Circulation Models and four emission scenarios, we show that climate change, by affecting the host and the pathogen separately, may uncouple their spatial distribution to create a mismatch in species interaction and so a lowering of disease transmission. Consequently, as climate change expands the ranges of both species polewards it may alleviate the ash dieback crisis in southern and occidental regions at the same time.

%B Scientific Reports %V 6 %G eng %R 10.1038/srep35303 %0 Journal Article %J Global Change Biology %D 2016 %T Global impacts of the 1980s regime shift %A Philip Chris Reid %A Renata E. Hari %A Grégory Beaugrand %A David M. Livingstone %A Christoph Marty %A Dietmar Straile %A Jonathan Barichivich %A Goberville, Eric %A Rita Adrian %A Yasuyuki Aono %A Ross Brown %A James Foster %A Pavel Groisman %A Pierre Hélaouët %A Huang‐Hsiung Hsu %A Richard R Kirby %A Jeff Knight %A Alexandra Kraberg %A Jianping Li %A Tzu‐Ting Lo %A Ranga B. Myneni %A Ryan P. North %A Alan J. Pounds %A Tim Sparks %A René Stübi %A Yongjun Tian %A Karen H. Wiltshire %A Dong Xiao %A Zaichun Zhu %K Climate %K Earth systems %K Global change %K Regime shift %K Statistical analysis %K Time series %K Volcanic forcing %X

© 2016 John Wiley {&} Sons Ltd. Despite evidence from a number of Earth systems that abrupt temporal changes known as regime shifts are important, their nature, scale and mechanisms remain poorly documented and understood. Applying principal component analysis, change-point analysis and a sequential t-test analysis of regime shifts to 72 time series, we confirm that the 1980s regime shift represented a major change in the Earth's biophysical systems from the upper atmosphere to the depths of the ocean and from the Arctic to the Antarctic, and occurred at slightly different times around the world. Using historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and statistical modelling of historical temperatures, we then demonstrate that this event was triggered by rapid global warming from anthropogenic plus natural forcing, the latter associated with the recovery from the El Chichón volcanic eruption. The shift in temperature that occurred at this time is hypothesized as the main forcing for a cascade of abrupt environmental changes. Within the context of the last century or more, the 1980s event was unique in terms of its global scope and scale; our observed consequences imply that if unavoidable natural events such as major volcanic eruptions interact with anthropogenic warming unforeseen multiplier effects may occur.

%B Global Change Biology %V 22 %G eng %R 10.1111/gcb.13106 %0 Journal Article %J Nature Climate Change %D 2015 %T Future vulnerability of marine biodiversity compared with contemporary and past changes %A Grégory Beaugrand %A Martin Edwards %A Virginie Raybaud %A Goberville, Eric %A Richard R Kirby %X

© 2015 Macmillan Publishers Limited. Many studies have implied significant effects of global climate change on marine life. Setting these alterations into the context of historical natural change has not been attempted so far, however. Here, using a theoretical framework, we estimate the sensitivity of marine pelagic biodiversity to temperature change and evaluate its past (mid-Pliocene and Last Glacial Maximum (LGM)), contemporaneous (1960-2013) and future (2081-2100; 4 scenarios of warming) vulnerability. Our biodiversity reconstructions were highly correlated to real data for several pelagic taxa for the contemporary and the past (LGM and mid-Pliocene) periods. Our results indicate that local species loss will be a prominent phenomenon of climate warming in permanently stratified regions, and that local species invasion will prevail in temperate and polar biomes under all climate change scenarios. Although a small amount of warming under the RCP2.6 scenario is expected to have a minor influence on marine pelagic biodiversity, moderate warming (RCP4.5) will increase by threefold the changes already observed over the past 50 years. Of most concern is that severe warming (RCP6.0 and 8.5) will affect marine pelagic biodiversity to a greater extent than temperature changes that took place between either the LGM or the mid-Pliocene and today, over an area of between 50 (RCP6.0: 46.9-52.4{%}) and 70{%} (RCP8.5: 69.4-73.4{%}) of the global ocean.

%B Nature Climate Change %V 5 %G eng %R 10.1038/nclimate2650 %0 Journal Article %J Proceedings of the Royal Society B: Biological Sciences %D 2014 %T Marine biological shifts and climate %A Grégory Beaugrand %A Goberville, Eric %A Christophe Luczak %A Richard R Kirby %K environmental science %X

Phenological, biogeographic and community shifts are among the reported responses of marine ecosystems and their species to climate change. However, despite both the profound consequences for ecosystem functioning and ser- vices, our understanding of the root causes underlying these biological changes remains rudimentary. Here, we show that a significant proportion of the responses of species and communities to climate change are determinis- tic at some emergent spatio-temporal scales, enabling testable predictions and more accurate projections of future changes.We propose a theory based on the concept of the ecological niche to connect phenological, biogeographic and long-term community shifts. The theory explains approximately 70{%} of the phenological and biogeographic shifts of a key zooplankton Calanus finmarch- icus in the North Atlantic and approximately 56{%} of the long-term shifts in copepods observed in the North Sea during the period 1958–2009.

%B Proceedings of the Royal Society B: Biological Sciences %V 281 %P 20133350 %G eng