Data file describing high frequency (every ~10 minutes), optial sensor-derived chemistry of river water from Trevor Creek near Toolik Field Station, North Slope of Alaska. Data file includes date, time, dissolved organic carbon (DOC) concentration, and nitrate concentration. Sensors (V2 s::can uv-vis spectrophotometers) were continuously deployed from June through August or September and optically determined nitrate and dissolved organic carbon concentrations.

Files used to generate the data for figures in: Rastetter, EB, Kwiatkowski, BL. An approach to modeling resource optimization for substitutable and interdependent resources. Ecological Modelling (2020). https://doi.org/10.1016/j.ecolmodel.2020.109033. This paper presents a hierarchical approach to modeling organism acclimation to changing availability of and requirements for substitutable and interdependent resources. Substitutable resources are resources that fill the same metabolic or stoichiometric need of the organism.

We deployed three eddy covariance towers along a burn severity gradient (i.e.

Stream temperature and discharge measured each summer for Roche Moutonnee Creek and Trevor Creek. Dataloggers measured stream temperature and stream height at regular intervals. Stream height is converted into stream discharge based on a rating curve calculated from manual discharge measurements throughout the season. The principal investigator in charge of the temperature and discharge measurements is Dr. Breck Bowden.

Vegetation (species) abundances were measured from LTER heath tundra herbivore exclosures using the point frame method. This file contains the number of pin hits per species for each subplot.

We use the Multiple Element Limitation (MEL) model to examine the responses of twelve ecosystems - from the arctic to the tropics and from grasslands to forests - to elevated carbon dioxide (CO2), warming, and 20% decreases or increases in annual precipitation.

We use a simple model of coupled carbon and nitrogen cycles in terrestrial ecosystems to examine how explicitly representing grazers versus having grazer effects implicitly aggregated in with other biogeochemical processes in the model alters predicted responses to elevated carbon dioxide and warming. The aggregated approach can affect model predictions because grazer-mediated processes can respond differently to changes in climate from the processes with which they are typically aggregated.

Relative percent cover was measured for plant species on Arctic LTER experimental plots at Toolik field station in moist acidic and non-acidic tundra
in greenhouse and control plots. Leaf percent carbon, percent nitrogen and percent phosphorus were collected from dominant species in greenhouse and control plots
on Arctic LTER experimental plots at Toolik field station in moist acidic, non-acidic tundra, wet sedge and shrub
tundra

Above ground plant biomass and leaf area were 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 and per cent carbon and nitrogen and phosphorous summaries for control and fertilized plots.

We used a fully factorial experiment to test effects of food availability and temperature (7.6, 12.7 and 17.4 degrees C; 50 days) on growth, consumption, respiration, and excretion of slimy sculpin (Cottus cognatus).

Weather data has been collected at Toolik Field Station (68 degrees 38'N, 149 degrees 36'W) since June 1988. The weather station located at the field station was originally installed by the Arctic Long Term Ecological Research (LTER) (ecosystems.mbl.edu/arc) and Toolik Field Station (TFS) assumed control of the station in 2007. The field station is an ideal location for maintaining long-term weather data, as it is located in a data sparse region and adds a data point along the north-south transect of the North Slope of Alaska, following along the Dalton Highway.

Weather data has been collected at Toolik Field Station (68 degrees 38'N, 149 degrees 36'W) since June 1988. The weather station located at the field station was originally installed by the Arctic Long Term Ecological Research (LTER) (ecosystems.mbl.edu/arc) and Toolik Field Station (TFS) assumed control of the station in 2007. The field station is an ideal location for maintaining long-term weather data, as it is located in a data sparse region and adds a data point along the north-south transect of the North Slope of Alaska, following along the Dalton Highway.

Understanding the impacts of climate change on freshwater ecosystems is highly dependent on quantifying the associated changes in instream temperatures. However, this can be complicated because these temperatures are related to both changing meteorology (e.g., air temperature and precipitation) and hydrology (e.g., instream flows and lateral inflows). The ability to predict climate related changes on instream thermal regimes in Arctic streams is limited by the minimal understanding of key processes and the availability of data to quantify heat fluxes.

Soil temperature data from the 1989 LTER Moist Acidic Tussock (MAT89) Experimental plots. The logging station was installed in 1990 in block 2 of a four block experimental block design. The plots are located on a hillside near Toolik Lake (68 38' N, 149 36'W). Two replicates depth profiles (10, 20 ,40 centimeters) were installed in each block 2 experimental plots. Frost heaving has caused uncertain depths of measurements for many of the profiles. This data set contains only the control profiles from 2008 to 2020.

This dataset consists of Eriophorum vaginatum tussock height and width (diameter) measurements, and was used to evaluate differences in physical strucutre of previously burned tundra (2007 Anaktuvuk River fire) and nearby unburned tundra. At each site, all tussocks that intersected four 100 meter transects were measured from soil surface to tussock top in four cardinal directions, and diameter was measured in two directions.

This file contains leaf area index (LAI) based on biomass measurements from an aboveground pluck in the southern portion of the Anaktuvuk River fire scar, and a nearby unburned site in late July 2017. Vegetation was sampled randomly at 10-m intervals along two 100 meter transects at both the burned and unburned sites. Vegetation was sampled within a 10X40 cm quadrat to the mineral layer, and plant material was sorted into new and old aboveground leaf and woody biomass by species.

Small mammals (rodents and shrews) were sampled 7-12 years following the Anaktuvuk River Fire to examine how post-fire ecological changes influence small mammal abundance. Small mammals were snap-trapped in August 2014, 2017-2019 at the site of the 2007 Anaktuvuk River Fire, and a nearby unburned control site. At each site, 120 traps were set in 3 parallel lines spaced 40m apart. Each trap was spaced 10m apart, baited, and set to rodent sign within one meter of the trap station. Traps were checked the following two mornings with all captures collected and sprung traps reset.

This file contains biomass measurements from vole-grazed and ungrazed Eriophorum vaginatum tussocks taken from the 2007 Anaktuvuk River Fire scar in 2019. Rodent-grazed and ungrazed tussocks were harvested to assess the impact voles have on biomass. Eighteen grazed tussocks and seven ungrazed tussocks were harvested and taken back to the lab. Ungrazed tussocks were subsampled to make seperation faster. Eight additional ungrzed tussocks were measured in the field and biomass estimates were made using allometry equations based on diameter.

Percent cover of tundra vole and brown lemming structures collected from within the Team Vole enclosure/exclosure fences near Nome, Toolik, Utqiagvik, AK 2019.

Climate change is increasing extreme weather events, but effects on high-frequency weather variability and the resultant impacts on ecosystem function are poorly understood. We assessed ecosystem responses of arctic tundra to changes in day-to-day weather variability using a biogeochemical model and stochastic simulations of daily temperature, precipitation, and light. Changes in weather variability altered ecosystem carbon, nitrogen, and phosphorus stocks and cycling rates.