Modeling reproductive traits of an invasive bivalve species under contrasting climate scenarios from 1960 to 2100
Authored by Yoann Thomas, Stephane Pouvreau, Melaine Gourault, Sebastien Petton, Laure Pecquerie, Goncalo M Marques, Christophe Cassou, Elodie Fleury, Yves-Marie Paulet
Date Published: 2019
DOI: 10.1016/j.seares.2018.05.005
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Abstract
Identifying the drivers that control the reproductive success of a
population is vital to forecasting the consequences of climate change in
terms of distribution shift and population dynamics. In the present
study, we aimed to improve our understanding of the environmental
conditions that allowed the colonization of the Pacific oyster,
Crassostrea gigas, in the Bay of Brest since its introduction in the
1960s. We also aimed to evaluate the potential consequences of future
climate change on its reproductive success and further expansion.
Three reproductive traits were defined to study the success of the
reproduction: the spawning occurrence, synchronicity among individuals
and individual fecundity. We simulated these traits by applying an
individual-based modeling approach using a Dynamic Energy Budget (DEB)
model. First, the model was calibrated for C. gigas in the Bay of Brest
using a 6-year monitoring dataset (2009-2014). Second, we reconstructed
past temperature conditions since 1960 in order to run the model
backwards (hindcasting analysis) and identified the emergence of
conditions that favored increasing reproductive success. Third, we
explored the regional consequences of two contrasting IPCC climate
scenarios (RCP2.6 and RCP8.5) on the reproductive success of this
species in the bay for the 2100 horizon (forecasting analysis). In both
analyses, since phytoplankton concentration variations were, at that
point, unknown in the past and unpredicted in the future, we made an
initial assumption that our six years of observed phytoplankton
concentrations were informative enough to represent ``past and future
possibilities{''} of phytoplankton dynamics in the Bay of Brest.
Therefore, temperature is the variable that we modified under each
forecasting and hindcasting runs.
The hindcasting simulations showed that the spawning events increased
after 1995, which agrees with the observations made on C. gigas
colonization. The forecasting simulations showed that under the warmer
scenario (RCP8.5), reproductive success would be enhanced through two
complementary mechanisms: more regular spawning each year and
potentially precocious spawning resulting in a larval phase synchronized
with the most favorable summer period. Our results evidenced that the
spawning dates and synchronicity between individuals mainly relied on
phytoplankton seasonal dynamics, and not on temperature as expected.
Future research focused on phytoplankton dynamics under different
climate change scenarios would greatly improve our ability to anticipate
the reproductive success and population dynamics of this species and
other similar invertebrates.
Tags
Energy budget model
Phytoplankton
growth
Suspended culture
Oyster crassostrea-gigas
Pacific oyster
Marine-invertebrates
Deb model
Ipcc scenarios
Reproductive traits
Crassostrea gigas
Bay
of brest
Biochemical-composition
Change
impacts
Peg-model