Contemporary evolution of an at-risk stickleback population during a severe drought

Populations can be granted conservation status because they harbour a set of unique traits, evolutionary histories, or ecological roles. Such populations are often isolated and specialized and, as such, can be particularly vulnerable to environmental disturbances. Even if distinct populations survive and adapt to severe disturbances, they could show changes in the very traits that made them distinct in the first place. Here, we leverage a natural “experiment” involving an unarmoured population of threespine stickleback (Gasterosteus aculeatus) in Rouge Lake (Haida Gwaii, BC) – a population listed as Special Concern under the Canadian Species at Risk Act. In 2015, Rouge Lake nearly dried up during a severe drought event; yet the stickleback population appeared to have fully recovered its abundance in subsequent years. Using phenotypic measurements, we assessed the extent to which evolution in this population was impacted by the drought. We document important shifts in several phenotypic ..., , # Contemporary evolution of an at-risk stickleback population during severe drought

## Description of the data and file structure

This dataset contains phenotypic measurements and associated metadata for an unarmoured population of threespine stickleback (*Gasterosteus aculeatus*) from Rouge Lake, Haida Gwaii (BC, Canada). This unique population experienced a severe drought in 2015, which resulted in a major demographic bottleneck. By comparing fish sampled before and after the drought, the dataset documents a marked increase in lateral plate number—the trait that originally motivated the population’s conservation listing under COSEWIC.

### Files and variables

#### File: rouge_morpho_data.csv

**Description:** Note: \"NA\" means data unavailable

##### Variables

* ID: Unique identifier assigned to an individual stickleback.
* site: Lake or outlet.
* year: Year of capture (2007, 2012, 2013, 2018, or 2022)
* sl: The standard length (mm) of a given individual.
* body_depth: The body dep...,