Data for the manuscript: Demographic basis of spatially structured fluctuations in a threespine stickleback metapopulation

Uncovering the demographic basis of population fluctuations is a central
goal of population biology. This is particularly challenging for spatially
structured populations, which require disentangling synchrony in
demographic rates from coupling via immigration. In this study, we fit a
stage-structured metapopulation model to a 29-year times series of
threespine stickleback abundance in the heterogeneous and productive Lake
Myvatn, Iceland. The lake comprises two basins (North and South) connected
by a channel through which the stickleback disperse. The model includes
time-varying demographic rates, allowing us to assess the potential
contributions of recruitment and survival, spatial coupling via
immigration, and demographic transience to the population’s large
fluctuations in abundance. Our analyses indicate that recruitment was only
modestly synchronized between the two basins, whereas survival
probabilities of adults were more strongly synchronized, contributing to
cyclic fluctuations in the lake-wide population size with a period of
approximately six years. The analyses further show that the two basins are
coupled through immigration, with the North Basin subsidizing the South
Basin and playing a dominant role in driving the lake-wide dynamics. Our
results show that cyclic fluctuations of a metapopulation can be explained
in terms of the combined effects of synchronized demographic rates and
spatial coupling.