Spatial and temporal patterns of greenness on the Yamal Peninsula, Russia: interactions of ecological and social factors affecting the Arctic normalized difference vegetation index

Abstract

The causes of a greening trend detected in the Arctic using the normalized difference vegetation index (NDVI) are still poorly understood. Changes in NDVI are a result of multiple ecological and social factors that affect tundra net primary productivity. Here we use a 25 year time series of AVHRR-derived NDVI data (AVHRR: advanced very high resolution radiometer), climate analysis, a global geographic information database and ground-based studies to examine the spatial and temporal patterns of vegetation greenness on the Yamal Peninsula, Russia. We assess the effects of climate change, gas-field development, reindeer grazing and permafrost degradation. In contrast to the case for Arctic North America, there has not been a significant trend in summer temperature or NDVI, and much of the pattern of NDVI in this region is due to disturbances. There has been a 37% change in early-summer coastal sea-ice concentration, a 4% increase in summer land temperatures and a 7% change in the average time-integrated NDVI over the length of the satellite observations. Gas-field infrastructure is not currently extensive enough to affect regional NDVI patterns. The effect of reindeer is difficult to quantitatively assess because of the lack of control areas where reindeer are excluded. Many of the greenest landscapes on the Yamal are associated with landslides and drainage networks that have resulted from ongoing rapid permafrost degradation. A warming climate and enhanced winter snow are likely to exacerbate positive feedbacks between climate and permafrost thawing. We present a diagram that summarizes the social and ecological factors that influence Arctic NDVI. The NDVI should be viewed as a powerful monitoring tool that integrates the cumulative effect of a multitude of factors affecting Arctic land-cover change. ReferencesBelopukova E B, Leibman M O and Tukacheva L A 1989 The effect of climatic parameters on ground temperature regime and active layer depth on the Yamal Peninsula Engineering and Engineering Construction Studies in the Yakutia Republic (Yakutsk: NTO) Bhatt U S, Walker D A, Raynolds M and Comiso J 2007 The relationship between sea ice variability and Arctic tundra on the pan-Arctic, regional, and site scales Eos Trans. AGU 88 (52) Fall Meet. Suppl. Abstract U41C-0612 Bhatt U S, Walker D A, Raynolds M K and Comiso J 2008 Circumpolar and regional analysis of the relationship between sea-ice variability, summer land-surface temperatures, Arctic tundra greenness and large-scale climate drivers

Trends in normalized difference vegetation index (NDVI) associated with urban development in northern West Siberia

“…The development has left significant footprints on the vegetation cover. These footprints were found not only at the development sites but also across large distances (Walker et al, 2009;Kumpula et al, 2012). More specifically, Kumpula et al (2011) reported extensive transformation from shrub-to more productive (greener) grass-and sedge-dominated tundra in NWS that reclaim artificial terrain disturbances at Bovanenkovskiy gas field, Yamal peninsula (70 • N).…”

“…For example, for the Yamal peninsula, Elsakov and Teljatnikov (2013) concluded that its widely referred greening (Macias-Fauria et al, 2012) could be traced to statistically significant changes over just 4.8 % of the total area. Moreover, this greening was linked to shrub growth on the patches with disturbed permafrost or within the patches of already established shrubs (Walker et al, 2009). Barichivich et al (2014) noted that browning in southern forest biomes could also be partially associated with disturbances.…”

“…As in other polar regions, biomes of northern West Siberia (Fig. 1), hereafter referred to as NWS, respond to global warming with complex patterns of multidirectional changes (Bunn and Goetz, 2006;Lloyd and Bunn, 2007;MacDonald et al, 2008;Walker et al, 2009;Bhatt et al, 2013). Although the patterns are geographically fragmented (Elsakov and Teljatnikov, 2013;Barichivich et al, 2014;Guay et al, 2014), the northern biomes (tundra and foresttundra) demonstrate widespread increase of the vegetation productivity ("greening").…”

Recent Declines in Warming and Vegetation Greening Trends over Pan-Arctic Tundra

“…Most tundra vegetation is summer-temperature limited so summer warming will generally enhance productivity, however, other local factors are also important such as glacial history [22], winter temperatures, snow cover, precipitation, soil moisture [23], and land-use history [24,25]. These factors are very important for understanding the very heterogeneous signals that are coming from global assessments of plot-scale response to experimental warming [23].…”

Long-Term Effects of Grazing and Global Warming on the Composition and Carrying Capacity of Graminoid Marshes for Moulting Geese in East Greenland

“…Jia et al 2009;Walker et al 2009). A variety of tundra manipulative experiments and observations suggest vegetation productivity is increasing with rising temperatures (e.g.…”