Predator-mediated resource limitation shapes body and head size variation in stickleback populations

Predator and prey communities are key drivers of phenotypic variation in
consumers, yet the ecological interactions shaping these traits remain
understudied in natural food webs. This dataset supports a comparative
study examining how phenotypic variation in 34 Greenlandic threespine
stickleback (Gasterosteus aculeatus) populations is influenced by the
presence of an intraguild predator, Arctic char (Salvelinus alpinus). The
dataset includes morphological measurements of stickleback body and head
size, zooplankton community composition, and biomass estimates. Our
findings indicate that in the presence of Arctic char, stickleback exhibit
larger body sizes with relatively smaller heads, consistent with
resource-mediated ontogenetic shifts observed in other fishes. Path
analysis suggests that predator-mediated changes in zooplankton
communities partially explain this shift, highlighting indirect effects of
top predators on consumer resource limitation and allometric trait
variation. This dataset provides valuable insights into the ecological
mechanisms underlying phenotypic diversity and can be leveraged for
further studies on trophic interactions, trait allometry, and evolutionary
ecology.