Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska
1
ABR, Inc.—Environmental Research & Services, P.O. Box 80410, Fairbanks, AK 99708, USA
2
University of Maine—Fort Kent, 23 University Dr., Ft. Kent, ME 04743, USA
*
Author to whom correspondence should be addressed.
Remote Sens. 2017, 9(10), 1024; https://doi.org/10.3390/rs9101024
Received: 17 August 2017 / Revised: 26 September 2017 / Accepted: 29 September 2017 / Published: 4 October 2017
(This article belongs to the Special Issue Remote Sensing of Arctic Tundra)
Ecosystem maps are foundational tools that support multi-disciplinary study design and applications including wildlife habitat assessment, monitoring and Earth-system modeling. Here, we present continuous-field cover maps for tundra plant functional types (PFTs) across ~125,000 km2 of Alaska’s North Slope at 30-m resolution. To develop maps, we collected a field-based training dataset using a point-intercept sampling method at 225 plots spanning bioclimatic and geomorphic gradients. We stratified vegetation by nine PFTs (e.g., low deciduous shrub, dwarf evergreen shrub, sedge, lichen) and summarized measurements of the PFTs, open water, bare ground and litter using the cover metrics total cover (areal cover including the understory) and top cover (uppermost canopy or ground cover). We then developed 73 spectral predictors derived from Landsat satellite observations (surface reflectance composites for ~15-day periods from May–August) and five gridded environmental predictors (e.g., summer temperature, climatological snow-free date) to model cover of PFTs using the random forest data-mining algorithm. Model performance tended to be best for canopy-forming PFTs, particularly deciduous shrubs. Our assessment of predictor importance indicated that models for low-statured PFTs were improved through the use of seasonal composites from early and late in the growing season, particularly when similar PFTs were aggregated together (e.g., total deciduous shrub, herbaceous). Continuous-field maps have many advantages over traditional thematic maps, and the methods described here are well-suited to support periodic map updates in tandem with future field and Landsat observations.
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Keywords:
plant functional types; Arctic tundra; vegetation mapping; random forest; phenology; reflectance composites; Landsat; North Slope; Alaska
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Link: http://catalog.northslope.org/catalog/entries/8595
Description: Raster map products for Regional Cover Mapping of Tundra Plant Functional Types in Arctic Alaska, circa 2015.
MDPI and ACS Style
Macander, M.J.; Frost, G.V.; Nelson, P.R.; Swingley, C.S. Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska. Remote Sens. 2017, 9, 1024. https://doi.org/10.3390/rs9101024
AMA Style
Macander MJ, Frost GV, Nelson PR, Swingley CS. Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska. Remote Sensing. 2017; 9(10):1024. https://doi.org/10.3390/rs9101024
Chicago/Turabian StyleMacander, Matthew J.; Frost, Gerald V.; Nelson, Peter R.; Swingley, Christopher S. 2017. "Regional Quantitative Cover Mapping of Tundra Plant Functional Types in Arctic Alaska" Remote Sens. 9, no. 10: 1024. https://doi.org/10.3390/rs9101024
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