Vascular plant species list, by quadrat, for harvests of tussock tundra, wet sedge tundra, dry heath tundra, and a toposequence which also included "shrub/lupine," "riverside willow" and "footslope Equisetum" communities. Includes results of long-term nutrient enrichment, increased temperature, and shade houses in selected tundra types.
Data Set Results
Late season thaw depth was measured in the Arctic Long Term Ecological Research (ARC LTER) experimental plots (1981 Moist Acidic Tussock, 1989 Moist Acidic Tussock, 2006 Low Fertilization Moist Acidic Tussock, 1989 Moist Non-acidic Tussock, 1989 Moist Non-acidic Non-tussock and 1989 Wet Sedge tundra) at Toolik Lake, Alaska using a steel thaw probe. Note: for 2017-2018 only 1989 Moist Non-Acidic Tussock Tundra and 2006 Low fertilization Moist Acidic Tussock Tundra were measured. For other sites it has become difficult to distinguish rocks from frozen soil with a steel thaw probe.
Biomass was harvested from six vegetation types along a toposequence on a floodplain terrace of the Sagavanirktok River in the northern foothills of the Brooks Range , Alaska (68degrees 46' N, 148 degrees 51' W 50m). The vegetation sites are; upland tussock tundra, "hilltop heath", a "hillslope shrub-lupine", a "footslope Equisetum", a wet sedge tundra, and a "riverside willow".
Quadrats (20cm x 20cm squares) along a line (block) were collected for plant biomass in mesic acidic tussock tundra. Each quadrat was separated into individual species, new and old aboveground and belowground biomass. The harvest occurred in early July to coincide with a 15N plant and soil harvest.
Quadrats were harvested for aboveground biomass from eight plots within a tussock, watertrack, and snowbed community at 3 sites - acidic tundra near Toolik (site of acidic LTER plots), nonacidic tundra near Toolik Lake(site of non-acidic LTER plots), and acidic tundra near Sagwon. All vascular species were sorted, divided into new and old growth, dried, and weighed. Lichens were separated by genus in all quadrats. In half of the quadrats (n=4), mosses were separated by species. Moss and lichen data are presented by species elsewhere (see 97lgmosslichen.txt).
Leaf area for select species was measured in arctic tundra experimental sites from late June into early August. Measurements were made in acidic and non acidic tussock tundra and in shrub tundra in control and fertilized plots.
Biomass in shrub tundra near Toolik Lake North Slope AK (68 degrees 38N, 149derees 34W). There were three harvests; Late May-early June; Late July-early August; Late August-early September. See Shaver and Chapin (Ecological Monographs, 61(1), 1991 pp.1-31.
Phenological stages of sedges were observed at a long term experimental moist tussock tundra site and a long-term experimental wet sedge tundra sites near Toolik Lake, AK. Also, ITEX maximum growth measurements were recorded on August 19th (moist tussock tundra). Experimental treatments at each site included factorial NxP, greenhouse and shadehouse and were begun in 1989. See 96gsphdc.html and 96gsphsg.html for phenological data on deciduous and evergeen species.
Plant available NH4, NO3, and PO4 was determined at sites near ARC LTER Toolik acidic tundra and at a toposequence along the floodplain of the Sagavanirktuk River using 2 N KCL and weak HCL extracts. This file complies data collected at different times from 1987 through 2001 and includes initial extracts taken for buried bag method of net nitrogen mineralization.
Above ground plant biomass was measured in a tussock tundra experimental site. The plots were set up in 1981 and have been harvested in previous years (See Shaver and Chapin Ecological Monographs, 61(1), 1991 pp.1-31.) This file contains the biomass numbers for each harvested quadrat.
A spectrophotometer was used to scan the canopy vegetation of ITEX harvest plots. The resulting reflectance spectra were used to calculate several vegetation indices of interest (NDVI, EVI, EVI2, PRI, WBI, Chlorophyll Index). Average values of these vegetation indices for each ITEX harvest plot are presented here. These plots also had biomass harvests performed and were analyzed for leaf area and nitrogen content (see 2003-2009gsharvest.csv, 2003-2009gsharvestLAI-N.csv).
Plant biomass in arctic heath experimental plots. Plots set up in 1989 with nitrogen, phosphorus, nitrogen plus phosphorus and a shade treatment were harvested for above ground biomass. Root mass was also measured on a smaller subsample.
Above ground plant and below ground stem biomass was measured in Arctic LTER tussock tundra experimental small mammal exclosures. Treatments included Control, Nitrogen plus Phosphorus with both fenced and unfenced plots. In addition a moist non-acidic tussock tundra site was harvested. Leaf areas were also measured for each quadrat but are in a separate file.
A harvest was conducted to determine productivity of rare species not found in at least 4 quadrats per site in a separate small quadrat aboveground biomass harvest (see 97lg3sbm.txt). Harvests occurred in a tussock, watertrack, and snowbed community at 3 sites - acidic tundra near Toolik (site of acidic LTER plots), nonacidic tundra near Toolik Lake(site of non-acidic LTER plots), and acidic tundra near Sagwon. Moss and lichen data are presented by species elsewhere (see 97lgmosslichen).
Biomass in tussock tundra experimental plots near Toolik Lake, North Slope, AK (68 degrees 38N, 149derees 34W). There were five harvests in 1983. This file is the May 21-22, 1983 harvest.
Biomass in heath tundra near Toolik Lake North Slope AK (68 degrees 38N, 149derees 34W). .There were three harvests;Late May-early June; Late July-early August; Late August-early September. See Shaver and Chapin (Ecological Monographs, 61(1), 1991 pp.1-31.
Plant biomass, leaf area, carbon, nitrogen, and phosphorus were measured in three wet sedge tundra experimental sites. Treatments at each site included factorial NxP and at the Toolik sites greenhouse and shade house. Treatments started in 1985 (Sag site) and in 1988 (Toolik sites).
Precipitation, collected from a wet/dry precipitation collector located near University of Alaska Fairbanks Toolik Field Station, North Slope of Alaska (68 degrees 37' 42"N, 149 degrees 35' 46"W) was sent out for standardized EPA rain water analysis. Nutrient chemistry was also run on a sub sample at the field station.
GPS locations and vegetation descriptions for the ITEX flux survey plots. Survey plots were located in the Toolik Lake LTER fertilization experiment in Alaska; at Imnavait Creek, Alaska; at Paddus, Latnjajaure and the Stepps site near Abisko in northern Sweden; at various sites in Adventdalen, Svalbard; in the Zackenberg valley, Northeast Greenland; at BEO near Barrow, Alaska and at the Anaktuvuk River Burn in Alaska. Measurements were made during the growing seasons 2003 to 2009.
Foliar carbon and nitrogen concentrations of the dominant species from within the ITEX flux survey plots 2003-2004. Plots were located in the Toolik Lake LTER moist acidic tussock experiment plots in Alaska; at Imnavait Creek, Alaska.
Dissolved inorganic carbon, carbon dioxide, and methane in waters from pre-labeled wet sedge plots near Toolik Lake, AK during the summer of 2006.
Soluble reactive phosphorus (SRP) and ammonium in waters from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2004.
The methane fluxes from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2001.
The methane fluxes from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2002.
Soil respiration of carbon dioxide, and methane in waters from wet sedge plots near Toolik Lake, AK during the summer of 2001.
Dissolved inorganic carbon, carbon dioxide, and methane in waters from pre-labeled wet sedge plots near Toolik Lake, AK during the summer of 2003.
This file contains 13C and 15N content from tussock tundra and wet sedge vegetation collected from experiemental plots during the years 2001-2006.
Soluble reactive phosphorus (SRP) and ammonium in waters from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2006.
The methane fluxes from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2005.
This file contains the 14C content of tussock tundra vegetation from 2002-2006. The 14C labeling occurred the summer of 2002.
Dissolved inorganic carbon, carbon dioxide, and methane in waters from pre-labeled wet sedge plots near Toolik Lake, AK during the summer of 2005.
Microbial respiration of carbon dioxide, and methane in waters from wet sedge plots near Toolik Lake, AK during the summer of 2001.
Soluble reactive phosphorus (SRP) and ammonium in waters from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2003.
Soil respiration of carbon dioxide, and methane in waters from wet sedge plots near Toolik Lake, AK during the summer of 2004.
Dissolved inorganic carbon, carbon dioxide, and methane in waters from pre-labeled wet sedge plots near Toolik Lake, AK during the summer of 2000.
The methane fluxes from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2003.
Dissolved organic carbon, SRP, and ammonium in waters from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2005
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This file contains the 14C content of tussock tundra vegetation from 2002-2005. The 14C labeling occurred the summer of 2002.
Soil respiration of carbon dioxide, and methane in waters from wet sedge plots near Toolik Lake, AK during the summer of 2002.
The methane fluxes from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2004.
This file contains the Specific Activity of 14C from dissolved and gaseous species of carbon sampled from tussock tundra and wet sedge plots near Toolik Lake, AK during the summer of 2005.
Soil respiration of carbon dioxide, and methane in waters from wet sedge plots near Toolik Lake, AK during the summer of 2003.
Dissolved inorganic carbon, carbon dioxide, and methane in waters from pre-labeled wet sedge plots near Toolik Lake, AK during the summer of 2001.
Soil respiration of carbon dioxide, and methane in waters from wet sedge plots near Toolik Lake, AK during the summer of 2005.
Two cores of peat, approximately 15 cm2, were cut to the depth at which mineral soils were encountered at each site. The sites of sampling correspond to an elevational gradient leading from the lakeside upslope to the begining of the water track at the ridgetop. Each sample was divided into three sections, one section to be used for radiocarbon age , one for loss on ignition, and the remainder to be kept for future needs.
Burned and unburned moist acidic tundra sites used to estimate C and N loss from the Anaktuvuk River Fire (2007). These sites were sampled in summer of 2008. Unburned sites were used to develop a method for estimating soil organic layer depth and plant biomass, and for determining the characteristics of unburned soil organic layers. In burned sites, we characterized residual organic soils and used biometric measurements of tussocks to reconstruct pre-fire soil organic layer depth.
In contribution to the Arctic Observing Network, the researchers have established two observatories of landscape-level carbon, water and energy balances at Imnavait Creek, Alaska and at Pleistocene Park near Cherskii, Russia. These will form part of a network of observatories with Abisko (Sweden), Zackenburg (Greenland) and a location in the Canadian High Arctic which will provide further data points as part of the International Polar Year.
The Biocomplexity Station was established in 2005 to measure landscape-level carbon, water and energy balances at Imnavait Creek, Alaska. The station is now contributing valuable data to the Arctic Observing Network that was established at two nearby stations. These will form part of a network of observatories with Abisko (Sweden), Zackenburg (Greenland) and a location in the Canadian High Arctic which will provide further data points as part of the International Polar Year.
The Biocomplexity Station was established in 2005 to measure landscape-level carbon, water and energy balances at Imnavait Creek, Alaska. The station is now contributing valuable data to the Arctic Observing Network that was established at two nearby stations. These will form part of a network of observatories with Abisko (Sweden), Zackenburg (Greenland) and a location in the Canadian High Arctic which will provide further data points as part of the International Polar Year.
The Biocomplexity Station was established in 2005 to measure landscape-level carbon, water and energy balances at Imnavait Creek, Alaska. The station is now contributing valuable data to the Arctic Observing Network that was established at two nearby stations. These will form part of a network of observatories with Abisko (Sweden), Zackenburg (Greenland) and a location in the Canadian High Arctic which will provide further data points as part of the International Polar Year.