Canada Centre for Remote Sensing Field measurements and remote sensing-derived maps of vegetation around two arctic communities in Nunavut F. Zhou, W. Chen, B. A. Marriner

Canada’s Natural Resources – Now and for the Future2 Introduction  Objectives  Quantitatively assess spatial distribution of vegetation around two northern communities using remote sensing technology  Provide vegetation information for  Community planning/development  Impact assessment of climate warming on  Ecosystems  Environment  Wildlife habitat

Canada’s Natural Resources – Now and for the Future3 Community Locations of the Study

Canada’s Natural Resources – Now and for the Future4 Field Measurements  Vegetation parameters  Leaf Area Index (LAI)  Cover Percent  Aboveground Biomass (all species)  Total 73 plots at 7 sites measured  34 plots of 3 sites at Iqaluit  39 plots of 4 sites at Clyde River  Each plot has a size of 0.5m by 0.5m, separated by 5 meters along a 100 meter transect  Include sparse, medium, and dense vegetation coverage  Remote sensing images used for site selection  Geographic Coordinates

Canada’s Natural Resources – Now and for the Future5 Harvest

Canada’s Natural Resources – Now and for the Future6 Vegetation Species  Arctic willow  Labrador tea  Arctic white heather  Mountain Avens  Lingonberry  Blueberry  Net-veined willow  lichen  Saxifrage  Sedge  Arctic oxytrope  Blue grass  moss  Pepper grass  Forbs  Mountain sorrel  Pepper grass  Crowberry

Canada’s Natural Resources – Now and for the Future7 Sorting Separate species Separate live and dead Separate leave and stems

Canada’s Natural Resources – Now and for the Future8 Weight (wet and dry)

Canada’s Natural Resources – Now and for the Future9 Measurement Results Veg. Param. Site (No. of Plots) IqaluitClyde River 1 ( 20 ) 2 ( 7 ) 3 ( 7 ) 1 ( 8 ) 2 ( 5 ) 3 ( 6 ) 4 ( 20 ) BiomassMean SE RSE 44%15%12%9%24%11%29% LAIMean SE RSE 44%14%7%8%21%8%22% Cover %Mean SE RSE 46%24%12%23%27%22%26%

Canada’s Natural Resources – Now and for the Future10 Images and Processes  Landsat 7 ETM+  Multiple bands covering from blue to near Infrared  Resolution: 30 by 30 meters  Geometrical correction  Atmospheric correction (6s)  true reflectance from vegetation (+background)  for result comparison of the two communities  Plot coordinates superimposed on the images  Reflectance at the measurement sites extracted from the images for regression analysis

Canada’s Natural Resources – Now and for the Future11 Regression between RS Images (Reflectance) and Vegetation Parameters  Three groups of linear regression model are experimented 1.Single band (3, 4 and 5) 2.Band combination (3 & 4; 4 & 5; and 3, 4 & 5) 3.Vegetation Index  Normalized Difference Vegetation Index (NDVI)  (b4-b3)/(b4+b3)  Soil Adjusted Vegetation Index (SAVI)  (b4-b3)*(1+L)/(b4+b3+L)  Ratio Vegetation Index -- (RVI)  b4/b3

Canada’s Natural Resources – Now and for the Future12 Regression Statistics  Single band vs. Vegetation parameter Linear regression Adjusted correlation coefficient R 2 for sample size bias Vegetation parameterCover %BiomassLAI band band band

Canada’s Natural Resources – Now and for the Future13 Regression Statistics (cont.)  Band combination vs. Vegetation parameter Linear regression Adjusted correlation coefficient R 2 for sample size bias Vegetation parameterCover %BiomassLAI bands 3 and bands 4 and bands 3, 4 and

Canada’s Natural Resources – Now and for the Future14 Regression Statistics (cont.)  Vegetation Indices vs. Vegetation parameter Linear regression Adjusted correlation coefficient R 2 for sample size bias Vegetation parameterCover %BiomassLAI Normalized Difference Vegetation Index (NDVI) Ratio Vegetation Index (RAI) Soil Adjusted Vegetation Index (SAVI)

Canada’s Natural Resources – Now and for the Future15 Regression Statistics (cont.)  Band combination  P-value of the coefficient for Bands 3 and 5, and the intercept is very big.  Band 4  P-value for variable coefficient and intercept is small intercept (<0.001).  SAVI ( Soil Adjusted Vegetation Index)  has the similar magnitude of P-values to those of Band 4.  has an advantage that background soil contribution to image reflectance is reduced.

Canada’s Natural Resources – Now and for the Future16 Regression Equations Leaf Area Index Aboveground Biomass Cover %  Soil Adjusted Vegetation Index ~ Vegetation Parameters

Canada’s Natural Resources – Now and for the Future17 Vegetation Cover % Map Iqaluit Clyde River

Canada’s Natural Resources – Now and for the Future18 Aboveground Biomass Map Iqaluit Clyde River

Canada’s Natural Resources – Now and for the Future19 Vegetation LAI Map Iqaluit Clyde River

Canada’s Natural Resources – Now and for the Future20 Vegetation Cover Statistics  Clyde River  ~50% of lands -- polar desert  ~30% -- polar semi-desert  Ecosystem with vegetation percent cover > 50% only accounts for ~1.5% of the lands  Iqaluit  ~30% of lands -- polar deserts  ~30% -- polar semi-deserts  Ecosystem with vegetation percent cover > 50% accounts for about 5% of the landmass

Canada’s Natural Resources – Now and for the Future21 Discussion  Relative sample errors of measurements reduce with increases in plot number and vegetation coverage.  For the two communities, SAVI has a good correlation coefficient with the measured vegetation parameters.  Vegetation in Arctic varies locally and regionally. Remote sensing is an efficient tool to investigate the spatial distribution and temporal variation of the vegetation in Arctic region. It usually could produce more accurate results.  The vegetation maps around the two communities are derived from the field measurements at 7 sites and RS images. More field measurements may be required to improve the accuracy of the results.

Canada’s Natural Resources – Now and for the Future22 The team in the field … Thank you