Multicentury perspective assessing the sustainability of the historical harvest of seaducks

Published in: Proceedings of the National Academy of Sciences (PNAS) on April 1, 2019

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Historical Arctic seabird harvests were unsustainable

 

One of the main challenges in wildlife conservation biology is to understand what factors affect vulnerable populations. Often, wildlife population surveys are limited and only extend back a few decades at most, challenging our ability to understand what factors affect populations over time. These problems are most pronounced in remote areas like the Arctic, where wildlife monitoring is limited. For example, the population of the common eider, a seaduck long sought by Inuit for its meat and down, once numbered in the millions in the Eastern Canadian Arctic-Greenland region, but reports by northerners and some wildlife surveys suggested substantial reductions by the late 20th Century. Although hunting pressures were suspected to be the cause of the population declines, scientists have been trying to better understand factors affecting these populations to estimate how much hunting in a season is sustainable.

 

A new study published today in Proceedings of the National Academy of Sciences and led by scientists at the University of Ottawa showed that eider populations likely succumbed to hunting pressures in the mid-20th Century. The researchers used a novel method to track how nesting bird populations changed over time, even before population census data were collected. Their method involved taking lake sediment cores from the bottom of small lakes and ponds in Canada’s Eastern Arctic in the main breeding range where the common eiders nest.

 

Over time, sediments slowly accumulate at the bottom of lakes, archiving a detailed history of biological and chemical changes in those lakes, much like tree rings reveal historical information. When birds colonize a new area, they begin to fertilize the local environment with feces and carcasses, drastically changing the nutrient levels in the water. Scientists are discovering new and more sensitive ways to detect how birds alter the environment where they nest, allowing more detailed historical interpretations of how and when bird populations increased or collapsed.

 

By examining a range of chemical compounds recorded in pond sediments, including sterols, stanols, and nitrogen isotopes, the scientists found evidence that common eider populations in Hudson Strait near Cape Dorset, Nunavut, declined in the mid to late 20th Century, during a period of intense hunting pressure by Greenlanders and the relocation of nearby Inuit communities.

 

The scientists also looked for evidence of population decline at more remote eider nesting sites with lower hunting pressure, and found that indicators of eider populations remained stable in places where hunting pressure was low or absent. The eider population decline near Cape Dorset coincided with increased sales in firearms and motorized boats in Greenland in the mid 20th Century, indicating eider harvest at this time was unsustainable.  

 

 “Our study shows that hunting restrictions were necessary to prevent the collapse of the eiders in their core breeding area”, explained lead author Dr. Kathryn Hargan, a W. Garfield Weston postdoctoral fellow and a L’Oréal-UNESCO postdoctoral fellow at the University of Ottawa at the time the research was done.

 

“One of the biggest challenges we face in the ecological and environmental sciences is the lack of long-term monitoring data. Tools such as these offer a new perspective into tracking environmental changes going back hundreds of years, and can potentially revolutionize wildlife conservation efforts”, said Prof. Jules Blais from the University of Ottawa, who supervised the study.

 

"It is amazing to think that changes in the hunting practices of Greenland that occurred over the last century can be detected in the nutrient profiles of pond sediment found on remote eider duck colonies in the Canadian Arctic" said Dr. Grant Gilchrist, Arctic biologist at Environment and Climate Change Canada, a member of the research team.

 

This study was a partnership between indigenous, academic, and government partners. Other participating organizations in the study were Environment and Climate Change Canada, Carleton University, Acadia University, and Queen's University.

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Contact information for authors:

Jules Blais

Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada

Tel: (613) 562-5800 Ext. 6650 Jules.Blais@uottawa.ca  

Kathryn Hargan

Keck Sciences Department

Claremont McKenna, Pitzer, and Scripps Colleges

925 N. Mills Ave., Claremont, CA 91711

kathrynhargan@gmail.com

 

Grant Gilchrist

Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1S 5B6, Canada

Nik Clyde

Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1S 5B6, Canada

Mark Forbes

Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada

 

Mark Mallory

Department of Biology, Acadia University, 33 Westwood Ave., Wolfville, NS, B4P 2R6, Canada

Sam Iverson

Canadian Wildlife Service, Environment and Climate Change Canada, Gatineau, QC, K1A 0H3, Canada

&

​Wildlife Research Division, Science and Technology Branch, Environment and Climate Change Canada, Ottawa, ON, K1S 5B6, Canada.

John Smol

Paleoecological Environmental Assessment and Research Laboratory (PEARL)

Department of Biology, Queen’s University, Kingston, ON, K7L 3N6, Canada

smolj@queens.ca

Neal Michelutti

Paleoecological Environmental Assessment and Research Laboratory (PEARL)

Department of Biology, Queen’s University, Kingston, ON, K7L 3N6, Canada

Linda Kimpe

Department of Biology, University of Ottawa, Ottawa, ON, K1N 6N5, Canada