There are a variety of ways to combine ggplot2 plots with a single shared axis, but things can get tricky if you want a lot of control over all plot elements. I show four approaches to make such a plot: using facets and with packages cowplot, egg and patchwork.

Checking for autocorrelation must be done carefully when some observations are missing from a time series or the time series is measured for independent groups. I show an approach where I pad the dataset with NA via tidyr::complete() to fill in any missed sampling times and make sure groups are considered independent prior to calculating the autocorrelation function.