DOI: 10.5061/dryad.bzkh189m1
title: Environment- and system-specific interactions between population and trait dynamics

description: Understanding population dynamics across environmental contexts is
 essential to predict ecosystem stability. Functional traits influence
 population growth, which can in turn influence the traits and thus create
 feedback between population and trait dynamics. Here, by augmenting models
 of population and trait change with trait and population information,
 respectively, we demonstrate that such feedback occurred in an autotrophic
 but not in a heterotrophic microbial system. Furthermore, exposure to a
 pollutant disrupted this feedback: trait change and population growth
 ceased to interact in either system. Finally, when the models augmented
 with trait/population information were superior, the improvement was
 substantial, showing that density-trait feedbacks are potentially large,
 even though they are system- and environment-specific.
description: # Ciliates and cyanobacteria: populations and traits ## Data All data is
 stored in the **data/** folder. This contains two CSVs.
 data/**ciliates.csv** : cilate system data with following columns : *
 species : abbreviated species/genus name (string) * strain : strain name
 (string) * treat : treatment abbreviation - C control, A atrazine, T
 temperature, AT atrazine and temperature (string) * day : sampling time in
 days (float) * density : cell density in cells per millilitre (float) *
 aspect_ratio : mean cell aspect ratio (float) * size : mean cell surface
 area in square micrometres (float) * speed : mean cell movement speed in
 micrometres per second (float) * linearity : mean linearity of cell
 movement (float) data/**cyanobacteria.csv** : * day : sampling time in
 days (integer) * strain : strain name (string) * species : cyanobacteria
 clade name (string) * treat : treatment abbreviation (string / factor) * C
 : control * A : atrazine * T : temperature * AT : atrazine and temperature
 * repl : replicate number between 1 and 3 (integer) * density : cell
 density in cells per microlitre (float) * size : unitless mean cell size
 as quantified by the forward scatter of the flow cytometer (float) *
 phycoerythrin : unitless mean phycoerythrin quantity as quantified by the
 flourescence channels of the flow cytometer (float) * chlorophyll :
 unitless mean chlorophyll quantity as quantified by the flourescence
 channels of the flow cytometer (float) * phycocyanin : unitless mean
 phycocyanin quantity as quantified by the flourescence channels of the
 flow cytometer (float) ## Code Code files to run analyses and generate
 figures associated with manuscript "Environment- and system-specific
 interactions between population and trait dynamics". Created figures
 will be saved in the figures/ folder (which does not initially exist - you
 will be prompted to create it when saving the plots). * **00-data.r** :
 load in the raw data and transform into more useful forms including
 performing the PCA to aggregate the traits * **01-fit-models.r** : fit the
 different models described in text i.e. growth ~ f(N, T), trait change ~
 g(N, T) * **02-bootstrapping.r** : run the PBLR test * **03-model-info.r**
 : combine and summarise the test results * **04-plots.r** : create the
 figures