See also:

Waterfowl in the Old Crow Flats
 
Old Crow Temperatures
 
Old Crow Precipitation

Arctic Borderlands Ecological Knowledge Co-op

What is happening?

• This map of the Old Crow Flats uses different colours to represent what has happened to water levels between 1973 and 1999.
• The preliminary conclusion is that there has been a decline in about 6.8% of the surface area of water on the Flats (spots shown in red above). This includes only areas that have completely dried up and not those areas where the water levels decreased without exposing the lake bottom.
• It appears that most of the change in the study area came from partial draining of two large lakes and many smaller ones.
• For a more detailed look at the map click here. Warning: this higher resolution image (285kb, 2600 x 2500 pixels) may take a very long time to load...

Why is it happening?

• The lakes in Old Crow Flats have been changing for thousands of years as part of a natural cycle. This study suggests there is an imbalance between the rate at which lakes drain and the rate at which they refill.
• We can speculate about the role of climate warming in this change. The temperature indicator for Old Crow reveals a trend towards warmer temperatures in summer although there is no obvious trend in precipitation. Higher temperatures should increase rates of evaporation.

Why is it important?

• Old Crow Flats is a large system of lakes and wetlands in the North Yukon which is the home of a variety of breeding and molting waterfowl species during the summer. The Flats also provide important habitat for peregrine falcons, shorebirds, songbirds and aquatic and terrestrial mammals. Changes in water levels in the many lakes and wetlands of this area could have important effects on the wildlife that inhabit this area.

Technical Notes

• The area of surface water in the Old Crow Flats was measured from a series of satellite images obtained from various Landsat satellites between 1973 and 1999. The ground resolution varied with the type of image and ranged from 60 metres to 25 metres.
• Each image was analyzed by using a computer to separate the image into "land" and "water" classes and then comparing differences over time.
• Further details on this study are available from Jim Hawkings at the Canadian Wildlife Service office in Whitehorse, YT.