Rapid warming leads to greening of the tundra biome
Abstract
The tundra biome is rapidly warming, but the impacts of recent warming on tundra plant productivity remain uncertain. Here, we assess changes in plant productivity and productivity-temperature relationships for circumpolar arctic tundra using more than three decades of Landsat satellite imagery and an ensemble of climate data sets. We first compare Landsat maximum summer NDVI (NDVImax) against several decades of biomass harvests from northern Canada and a network of shrub ring-width measurements from northern Alaska and Russia. These comparisons indicate Landsat NDVImax is a robust indicator of annual plant productivity in graminoid and shrub tundra. We then evaluate trends in Landsat NDVImax from 1984 to 2016 for North American and western Eurasian tundra, as well as from 1999 to 2016 when imagery was also available from eastern Eurasia. We find that mean NDVImax significantly increased during both time periods at a rate of 2 - 3 % per decade (P < 0.05). Plant productivity significantly (P ≤ 0.05) increased across 30% of the study area from 1984 to 2016, decreased across 3% of the study area, and exhibited no secular trend (P > 0.05) in the remaining areas. Interannual variability in mean NDVImax was strongly influenced by current and prior summer air temperatures from 1984 to 2016 (r2 > 0.80). Rising summer air temperatures thus appear to have widely stimulated tundra plant productivity since the early 1980s, leading to an overall greening of the biome. Nevertheless, plant productivity did not appear to increase in many areas that warmed, possibly due to water limitations or other factors imparting resistance to change. These findings provide important evidence for recent impacts of climate change on a fundamental aspect of ecosystem function in the tundra biome, while also highlighting the need to better understand landscape heterogeneity in plant response to rising temperatures.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.B14C..02B
- Keywords:
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- 0414 Biogeochemical cycles;
- processes;
- and modeling;
- BIOGEOSCIENCESDE: 0439 Ecosystems;
- structure and dynamics;
- BIOGEOSCIENCESDE: 0475 Permafrost;
- cryosphere;
- and high-latitude processes;
- BIOGEOSCIENCESDE: 1640 Remote sensing;
- GLOBAL CHANGE