Major changes in fish thermal habitat diversity in Canada’s Arctic lakes due to climate change

Climate warming is a major disruptor of fish community structure globally. We use large-scale geospatial analyses of 447,077 Canadian Arctic lakes to predict how climate change would impact lake thermal habitat diversity across the Arctic landscape. Increases in maximum surface temperature (+2.4–6.7 °C), ice-free period (+14–38 days), and thermal stratification presence (+4.2–18.9%) occur under all climate scenarios. Lakes, currently fishless due to deep winter ice, open up; many thermally uniform lakes become thermally diverse. Resilient coldwater habitat supply is predicted; however, thermally diverse lakes shift from providing almost exclusively coldwater habitat to providing substantial coolwater habitat and previously absent warmwater habitat. Across terrestrial ecozones, most lakes exhibit major shifts in thermal habitat. The prevalence of thermally diverse lakes more than doubles, providing refuge for coldwater taxa. Ecozone-specific differences in the distribution of thermally d..., Overview of the Methods Used in This Paper
 
The following is an overview of the methods that we used in this paper. Each paragraph has an accompanying sub-section within the Methods section that provides more details. To develop the approach used in this paper, we applied both empirical and semi-mechanistic methods to build the set of predictive models needed to fulfill our primary objective: (i) predicting the impacts of climate change on the seasonal progression of thermal structure in Canadian Arctic lakes: and (ii) assessing how those impacts would change the character and diversity of the fish communities resident in those lakes24,35. A summary of issues addressed, and methods used follows:
 
(i) Ground-Truthing Lake Morphometry: Lake shape is a primary determinant of lake thermal structure. We used the GIS-based estimates of Canadian Arctic lake morphometry as the basis for our study, hereafter the Arctic GIS lake database13. Our Arctic GIS lake database provides the basic inform..., Spreadsheet editor to view files (e.g., Microsoft Excel). R to execute code., ## This README file was generated on 2024-02-09 by Daniel P. Gillis.

GENERAL INFORMATION

1. Title of Dataset: Major changes in fish thermal habitat diversity in Canada’s Arctic lakes due to climate change

2. Author Information
A. Corresponding Author:
Name: Daniel P. Gillis
Institution: 1) University of Toronto, Toronto, ON, Canada 2) Fisheries and Oceans Canada, Vancouver, BC
Email:
B. Co-Author 1:
Name: Charles K. Minns
Institution: University of Toronto, Toronto, ON, Canada
C. Co-Author 2:
Name: Steven E. Campana
Institution: University of Iceland, Reykjavik, Iceland
D. Co-Author 3:
Name: Brian J. Shuter
Institution: University of Toronto, Toronto, ON, Canada

3. Geographical location: Canadian Arctic. Focus of analysis is on areas at least 60 degrees N latitude.

4. Funding sources:
A. This work was supported by grants from the Canadian Network for Aquatic Ecosystems Services and the Discovery Grant program of the Natur...