Change in threespine stickleback defensive traits, following brook trout introduction

In recent decades, numerous observations have been made of evolution
induced by anthropogenic change in natural populations. Evolution in
response to harvest, climate change, pollution, landscape change, and
introduced invasive species is common. In the article "Evolution of
threespine stickleback (Gasterosteus aculeatus) defensive traits following
the stocking of brook trout (Salvelinus fontinalis)" in the American
Naturalist, we provide evidence for evolution in a new context by
documenting a large increase in the frequency of defensive pelvic spines
in two unusual threespine stickleback (Gasterosteus aculeatus) populations
previously shown to mostly lack such structures. These populations, in
Parc national du Lac-Témiscouata, Québec, Canada, were historically free
of predatory fish and consisted nearly entirely of pelvic-spineless
stickleback. This phenotypic change coincided with the stocking of the
lakes with brook trout (Salvelinus fontinalis), a stickleback predator,
and the introductions of other species used by anglers as live bait. The
rapid evolutionary change towards a more defensive morph in the
populations should prompt increased caution regarding the effects of
management practices on native species. Here we provide data (in csv
files) and code (in an R Markdown file) necessary to reproduce the
analyses and figures in the article. These data include lateral plate and
defensive spine phenotypes observed within the park's threespine
stickleback populations, as well as historical stocking data that was
obtained from the park and the provincial government.