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Monitoring - Habitat

Satellite Monitoring of Plant Productivity

Rationale

Arctic willow.
Arctic willow.

Some environmental changes are best understood by looking at entire landscapes. A "big picture" approach provides information about how entire ecosystems function and change. This can provide information that complements smaller scale monitoring activities. Parks Canada Agency uses Advanced Very High Resolution Radiometer (AVHRR) satellite images to monitor landscapes. Of special interest to Parks Canada Agency is the Normalized Difference Vegetation Index (NDVI), which is recorded by the AVHRR satellite. NDVI measures the productivity or growth of vegetation. AVHRR satellite images provide information about plant productivity, peak times of vegetation growth and snow cover, which can be used to monitor long term changes in the park environment.

Objectives

  • To monitor plant productivity, the timing of plant growth and the extent of snow cover in Aulavik, Ivvavik and Tuktut Nogait national parks.

Methods and Information Collected

  • Satellite monitoring of plant productivity is conducted for the Western Arctic Field Unit in Aulavik, Ivvavik and Tuktut Nogait national parks. This is part of a larger program that is conducted in 11 National Parks.
  • Satellite images are taken from April to October each year. The images are created by combining the best images taken over a 10-day period.
  • Information from the composite images are used to determine primary productivity, the timing of plant growth and the extent of snow cover.
  • Analysis of satellite images is conducted by the Parks Canada Western Canada Service Centre in Winnipeg.
  • A series of ground sample sites were selected in different vegetation types in each park. These sites are used for analysing productivity information measured from the satellite images.

Years of Data

  • 1998-ongoing

Partners

  • Parks Canada Agency - Western Canada Service Centre (Winnipeg)
AVHRR satellite monitoring in Tuktut Nogait National Park. AVHRR satellite monitoring in Tuktut Nogait National Park. AVHRR satellite monitoring in Tuktut Nogait National Park.
  AVHRR satellite monitoring in Tuktut Nogait National Park.  

Results

  • Data from 1999 to 2001 for Ivvavik and Tuktut Nogait national parks, and from 1998 to 2001 for Aulavik National Park, were analysed to determine if there are changes in NDVI.
  • NDVI was found to be different in the spring of these three years. These changes may be due to a later start in the growing season since 1998.
  • NDVI at the peak of growing seasons and midsummer did not change from year to year. The stability of NDVI values in midsummer may make this period a good indicator of long term changes in vegetation growth.
  • The timing of vegetation growth for 1998 and 1999 for all three parks is indicated in the table below.
* 1998-1999 estimated dates based on a temperature value>10,000
  Ivvavik Aulavik Tuktut Nogait
1998
1999
1998
1999
1998
1999
Spring Thaw
May 16
May 16
June 6
June 16
Na
June 6
Peak of Growth
July 16
July 16
July 16
Aug 6
Na
Aug 6
Winter Freeze-up
Sept 6
Sept 26
Aug 16
Sept 16
Na
Oct 6

  • In 2000 the methods for analysing the timing of plant growth changed to measure growing season onset and end.

* 2000 estimated dates based on NDVI value of 0.09
  Ivvavik Aulavik Tuktut Nogait
Growing Season Onset
June 6
June 26
June 26
Peak of Growth
July 26
July 26
July 26
Growing Season End
Sept 16
Sept 16
Sept 16