Assessing the sensitivity of bivalve populations to global warming using an individual‐based modelling approach

Abstract

Climate change exposes benthic species populations in coastal ecosystems to a combination of different stressors (e.g., warming, acidification and eutrophication), threatening the sustainability of the ecological functions they provide. Thermal stress appears to be one of the strongest drivers impacting marine ecosystems, acting across a wide range of scales, from individual metabolic performances to geographic distribution of populations. Accounting for and integrating the response of species functional traits to thermal stress is therefore a necessary step in predicting how populations will respond to the warming expected in coming decades. Here, we developed an individual-based population model using a mechanistic formulation of metabolic processes within the framework of the dynamic energy budget theory. Through a large number of simulations, we assessed the sensitivity of population growth potential to thermal stress and food conditions based on a climate projection scenario (Representative Concentration Pathway; RCP8.5: no reduction of greenhouse gas emissions). We focused on three bivalve species with contrasting thermal tolerance ranges and distinct distribution ranges along 5,000 km of coastline in the NE Atlantic: the Pacific oyster (Magallana gigas), and two mussel species: Mytilus edulis and Mytilus galloprovincialis. Our results suggest substantial and contrasting changes within species depending on local temperature and food concentration. Reproductive phenology appeared to be a core process driving the responses of the populations, and these patterns were closely related to species thermal tolerances. The nonlinear relationship we found between individual life-history traits and response at the population level emphasizes the need to consider the interactions resulting from upscaling across different levels of biological organisation. These results underline the importance of a process-based understanding of benthic population response to seawater warming, which will be necessary for forward planning of resource management and strategies for conservation and adaptation to environmental changes.

Trans-Atlantic Distribution and Introgression as Inferred from Single Nucleotide Polymorphism: Mussels Mytilus and Environmental Factors

“…A contraction of the western Atlantic M. edulis population northward by 350 km of Cape Hatteras has been a sign of serious displacements of populations, which should be expected as a consequence of global climate changes [57]. A northward shift of M. edulis and M. galloprovincialis populations in Europe in response to climate changes in the North Atlantic area has been also predicted by an individual-based model [58].…”

“…and reported salinity among the most important environmental drivers in the North Atlantic and Arctic regions. However, other authors indicate temperature and food concentration as prime environmental factors affecting distribution and geographic range of Mytilus populations [57][58][59].…”

Forecasting species range dynamics with process‐explicit models: matching methods to applications

“…Combining multiple approaches (e.g. using output from an eco‐physiological model as input into an IBM or population model) could draw on the strengths of different approaches (Malishev et al ; Thomas & Bacher ). However, more complex models can take longer to build, lack appropriate data to parameterise, and can also be more difficult to interpret and communicate to other researchers and decision‐makers (Dormann et al ).…”

The meagre future of benthic fauna in a coastal sea—Benthic responses to recovery from eutrophication in a changing climate

“…It should also be noted that although the scenario simulations combine a large number of drivers and responses in the ecosystem, there are additional potentially important processes not considered in this study, such as changes in reproductive phenology (Thomas & Bacher, 2018) and effects of salinity, acidification and species invasions on the benthic communities (Cloern et al, 2016;Crain, Kroeker, & Halpern, 2008;Holopainen et al, 2016;Norkko et al, 2012). For example, projected reductions in salinity ( Figure S1, Meier, Müller-Karulis, et al, 2012) would probably shift the benthic species composition towards a larger proportion of species of freshwater origin, but the effects on biomass and productivity of such a shift are highly uncertain (Remane, 1934;Vuorinen et al, 2015).…”