TY - JOUR

T1 - Temperature‐mediated changes in zooplankton body size: large scale temporal and spatial analysis

AU - Evans, Lowri

AU - Hirst, Andrew

AU - Kratina, Pavel

AU - Beaugrand, Gregory

PY - 2020/4

Y1 - 2020/4

N2 - Climate warming has been linked with changes in the spatiotemporal distribution of species and the body size structure of ecological communities. Body size is a master trait underlying a host of physiological, ecological and evolutionary processes. However, the relative importance of environmental drivers and life history strategies on community body size structure across large spatial and temporal scales is poorly understood. We used detailed data of 83 copepod species, monitored over a 57‐year period across the North Atlantic, to test how sea surface temperature, thermal and day length seasonality relate to observed latitudinal‐size clines of the zooplankton community. The genus Calanus includes dominant taxa in the North Atlantic that overwinter at ocean depth. Thus we compared the copepod community size structure with and without Calanus species, to partition the influence of this life history strategy. The mean community body size of copepods was positively associated with latitude and negatively associated with temperature, suggesting that these communities follow Bergmann's rule. Including Calanus species strengthens these relationships due to their larger than average body sizes and high seasonal abundances, indicating that the latitudinal‐size cline may be adaptive. We suggest that seasonal food availability prevents high abundance of smaller‐sized copepods at higher latitudes, and that active vertical migration of dominant pelagic species can increase their survival rate over the resource‐poor seasons. These findings improve our understanding of the impacts that climate warming has on ecological communities, with potential consequences for trophic interactions and biogeochemical processes that are well known to be size dependent.

AB - Climate warming has been linked with changes in the spatiotemporal distribution of species and the body size structure of ecological communities. Body size is a master trait underlying a host of physiological, ecological and evolutionary processes. However, the relative importance of environmental drivers and life history strategies on community body size structure across large spatial and temporal scales is poorly understood. We used detailed data of 83 copepod species, monitored over a 57‐year period across the North Atlantic, to test how sea surface temperature, thermal and day length seasonality relate to observed latitudinal‐size clines of the zooplankton community. The genus Calanus includes dominant taxa in the North Atlantic that overwinter at ocean depth. Thus we compared the copepod community size structure with and without Calanus species, to partition the influence of this life history strategy. The mean community body size of copepods was positively associated with latitude and negatively associated with temperature, suggesting that these communities follow Bergmann's rule. Including Calanus species strengthens these relationships due to their larger than average body sizes and high seasonal abundances, indicating that the latitudinal‐size cline may be adaptive. We suggest that seasonal food availability prevents high abundance of smaller‐sized copepods at higher latitudes, and that active vertical migration of dominant pelagic species can increase their survival rate over the resource‐poor seasons. These findings improve our understanding of the impacts that climate warming has on ecological communities, with potential consequences for trophic interactions and biogeochemical processes that are well known to be size dependent.

KW - biogeography

KW - body size

KW - climate warming

KW - continuous plankton recorder

KW - seasonality

KW - species distribution

KW - temperature

KW - traits

KW - zooplankton

U2 - 10.1111/ecog.04631

DO - 10.1111/ecog.04631

M3 - Article

VL - 43

SP - 581

EP - 590

JO - Ecography

JF - Ecography

SN - 1600-0587

IS - 4

ER -