Tundra vegetation properties along a latitudinal gradient of the Yamal Region of Russia
Howard
E
Epstein, University of Virginia, hee2b@virginia.edu
(Presenting)
Donald
A
Walker, University of Alaska Fairbanks, ffdaw@uaf.edu
Patrick
Kuss, University of Bern, patrick.kuss@ips.unibe.ch
Elina
Kaarlejarvi, Arctic Centre, Rovaniemi, Finland, elina.kaarlejarvi@gmail.com
An understanding of ecosystem interactions in any system is predicated by knowledge of the spatial distribution of vegetation properties. In many regions of the Siberian arctic tundra, this baseline information on tundra vegetation in a spatial context does not exist in a systematic fashion. As part of a NASA/NEESPI Land Cover Land Use Change (LCLUC) project, we analyzed in detail the vegetation properties of three tundra locations along a latitudinal gradient in forest-tundra and arctic tundra east of the Ural Mountains, including the Yamal Peninsula. Our locations were situated near Nadym (65° 18 N), Laborovaya (67° 41 N), and Bovanenkova (Vaskiny Dachi 70° 17). At a minimum of two sites per location, using 50m x 50m grids, we systematically sampled leaf area index (LAI), Normalized Difference Vegetation Index (NDVI), species composition, vegetation biomass, and foliar nutrient concentrations. The LAI of vascular plants declined from an average of 1.08 m2 m-2 at Nadym to 0.36 at Vaskiny Dachi along the 5° latitudinal transect. NDVI values of the tundra vegetation did not decline with latitude and were 0.60 for Nadym, 0.67 for Laborovaya and 0.58 for Vaskiny Dachi. This is likely due to the contribution of non-vascular, understory vegetation to the NDVI signal. Related, average foliar nitrogen concentrations were greatest at Laborovaya, the site with the highest NDVI. Average tundra vegetation biomass decreased with latitude from 1130 g m-2 at Nadym to 636 g m-2 at Laborovaya and 451 g m-2 at Vaskiny Dachi. Biomass was linearly related to LAI (rē = 0.60), but not so to NDVI; outliers for Nadym showed lower than expected NDVI values, probably due to the dominance of highly reflective lichens. A key result is that, even along this transect of approximately 500 km, the heterogeneity of vegetation properties within a location can be greater than that over the entire transect.
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