Inter-annual variability of NDVI in response to long-term warming and fertilization in wet sedge and tussock tundra

Publication Type  Journal Article
Year of Publication  2005
Authors  Boelman, N. T.; Stieglitz, M.; Griffin, K. L.; Shaver, G. R.
Journal Title  Oecologia
Volume  143
Issue  4
Pages  588-597
Journal Date  May
ISBN Number  0029-8549
Accession Number  ISI:000229781100011
Key Words  aboveground biomass; arctic tundra; normalized difference vegetation index; simulated environmental-change; arctic dwarf-shrub; carbon-dioxide; growth-responses; northern alaska; climate-change; co2 flux; ecosystems; vegetation; biomass
Abstract  

This study explores the relationship between the normalized difference vegetation index (NDVI) and aboveground plant biomass for tussock tundra vegetation and compares it to a previously established NDVI-biomass relationship for wet sedge tundra vegetation. In addition, we explore inter-annual variation in NDVI in both these contrasting vegetation communities. All measurements were taken across long-term experimental treatments in wet sedge and tussock tundra communities at the Toolik Lake Long Term Ecological Research (LTER) site, in northern Alaska. Over 15 years (for wet sedge tundra) and 14 years (for tussock tundra), N and P were applied in factorial experiments (N, P and N + P), air temperature was increased using greenhouses with and without N + P fertilizer, and light intensity was reduced by 50% using shade cloth. during the peak growing seasons of 2001, 2002, and 2003, NDVI measurements were made in both the wet sedge and tussock tundra experimental treatment plots, creating a 3-year time series of inter-annual variation in NDVI. We found that: (1) across all tussock experimental tundra treatments, NDVI is correlated with aboveground plant biomass (r(2) =0.59); (2) NDVI-biomass relationships for tussock and wet sedge tundra communities are community specific, and; (3) NDVI values for tussock tundra communities are typically, but not always, greater than for wet sedge tundra communities across all experimental treatments. We suggest that differences between the response of wet sedge and tussock tundra communities in the same experimental treatments result from the contrasting degree of heterogeneity in species and functional types that characterize each of these Arctic tundra vegetation communities.

Notes  

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URL  <Go to ISI>://000229781100011
DOI  DOI 10.1007/s00442-005-0012-9