Environment- and system-specific interactions between population and trait dynamics

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., , , # 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 tem...