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Confounded winter and spring phenoclimatology on large herbivore ranges

April 21, 2013

Annual variation in winter severity and growing season vegetation dynamics appear to influence the demography of temperate herbivores but parsing winter from spring effects requires independent metrics of environmental conditions specific to each season. We tested for independence in annual variation amongst four common metrics used to describe winter severity and early growing season vegetation dynamics across the entire spatial distribution of elk (Cervus elaphus) in Wyoming from 1989 to 2006. Winter conditions and early growing season dynamics were correlated in a specific way. Winters with snow cover that ended early tended to be followed by early, but slow, rises in the normalized difference vegetation index (NDVI), while long winters with extended periods of snow cover were often followed by late and rapid rises in NDVI. Across the 35 elk ranges, 0.4–86.8 % of the variation in the rate of increase in NDVI’s in spring was explained by the date snow cover disappeared from SNOTEL stations. Because phenoclimatological metrics are correlated across seasons and shifting due to climate change, identifying environmental constraints on herbivore fitness, particularly migratory species, is more difficult than previously recognized.

Publication Year 2013
Title Confounded winter and spring phenoclimatology on large herbivore ranges
DOI 10.1007/s10980-012-9840-2
Authors David Christianson, Robert W. Klaver, Arthur Middleton, Matthew Kauffman
Publication Type Article
Publication Subtype Journal Article
Series Title Landscape Ecology
Index ID 70045160
Record Source USGS Publications Warehouse
USGS Organization Earth Resources Observation and Science (EROS) Center