Data for: Climate change-induced landscape alterations increase nutrient sequestration and cause severe oligotrophication of subarctic lakes. DOI: https://onlinelibrary.wiley.com/doi/10.1111/gcb.70314

This data set contains data for the nine lakes and their drainage areas, i.e. water chemistry data, temperature and Normalized Difference Vegetation Index data, as well as calculated sequestration of N and P based on relationships in the publication. 

Sampling and analyses of all water chemistry variables were based on standard protocols throughout the study period. These protocols are quality controlled and certified by the Swedish Board for Accreditation and Conformity Assessment (SWEDAC; https://www.swedac.se/). All physicochemical analyses have been performed at the Department of Aquatic Sciences and Assessment following international (ISO) and/or European (EN) standards.

Water chemistry data are openly available from the MVM Soil, Water and Environmental data platform at the Swedish University of Agricultural Sciences: https://miljodata.slu.se/MVM/Search. Enter lake names and select time period and parameters to download data. 
Temperature data used in the study have been obtained from Climate Research Unit Time-series database (CRU TS version 4.06) at https://crudata.uea.ac.uk/cru/data/hrg/.
NDVI data were extracted from the NOAA Climate data record (normalized NDVI version 4) using the Google Earth engine. https://www.ncei.noaa.gov/products/climate-data-records
Data on reindeer population size have been extracted from the Swedish Sami parliament https://www.sametinget.se/statistik/renhjorden

FILE INFORMATION:
Data files contain data for all years for each of the lakes/catchments. However, "null" (data lacking) is given for years where data were either missing, not extracted from data bases (T-data), or not used when the set criterion of at least 3 measures per year was not fulfilled (water chemistry data).  

Columns in the file Data catchments_NDVI_vegetationP_VegetationN_water chemistry2 contain the following variables: 
Name: Lake name 
EUid: European ID of the lake, used in European water management. The ID consists of the country abbreviation (SE) and the X and Y coordinates for the outlet of the lake, given in the 
CoordinateX: The X coordinate for the outlet of the lake in the SWEREF99 coordinate system.
CoordinateY: The Y coordinate for the outlet of the lake in the SWEREF99 coordinate system.
Year: Year of sample collection.
Air_T: The daily mean air temperature as C for the period June through September.
Drainage_area_size: The size of the drainage area in km2.
MaxNDVI: The maximum Normalized Difference Vegetation Index value for the drainage area. 
N_vegetation: The amount of sequestered nitrogen in drainage area vegetation (as ton N), calculated using the relationship outlined in the publication.
N_vegetation_average: The 3-year moving average for the amount of sequestered nitrogen in drainage area vegetation (as ton N).
Area_specific_N_vegetation: The amount of sequestered nitrogen in drainage area vegetation per square kilometer (as ton N/km2).
P_vegetation: The amount of sequestered phosphorus in drainage area vegetation (as ton P), calculated using the relationship outlined in the publication.
P_vegetation_average: The 3-year moving average for the amount of sequestered phosphorus in drainage area vegetation (as ton P).
Area_specific_P_vegetation: The amount of sequestered phosphorus in drainage area vegetation per square kilometer (as tonP/km2).
P_concentration: Annual mean water concentration of total phosphorus (as gP/L) based on at least 3 monthly values per year. If data were lacking (no monitoring) or if the criterion of at least three monthly values per year was not met, cells are marked null.
DIN_concentration: Annual mean water concentration of dissolved inorganic nitrogen (as gN/L) based on at least 3 monthly values per year. If data were lacking (no monitoring) or if the criterion of at least three monthly values per year was not met, cells are marked null.
TOC_concentration: Annual mean water concentration of total organic carbon (as mgC/L) based on at least 3 monthly values per year. If data were lacking (no monitoring) or if the criterion of at least three monthly values per year was not met, cells are marked null.

Columns in the file DataF4_Cover_estimation_of_dwarf_shrubs_in_the_Swedish_alpine_mountains contain the data from the National Inventory of Landscapes in Sweden (NILS)-monitoring sites that are plotted in figure 4 of the publication. Columns contain the following variables:
Period: The time interval (years) used for calculation the five-year average that is plotted in figure 4 of the publication.
Vegetation_type: The type of vegetation that has been extracted from NILS data bases. In the publication dwarf shrubs have been defined as species belonging to the following genera: Vaccinium, Cassiope, Kalmia, Empetrum, Phyllodoce, Rhododendron, Calluna, Arctostaphylos, Harrimanella, Arctous, Andromeda.
Source: The source for dwarf shrub cover data. This column refers to the site of the National Inventory of Landscapes in Sweden (NILS). Note that coordinates for the NILS sites are diffused in the data source given.
Year: The median-year for the period given in the first column of the file. This values has been plotted on the X-axis of figure 4 in the publication. 
Cover: The 5-year moving average of dwarf shrub cover (as %) plotted in the Y-axis of figure 4 in the publication. 

Columns in the file Data_F5_ndvi_plant biomass_N_P contain the data that are plotted in figure 5 of the publication. Columns contain the following variables:
NILS-grid: An identification number for the NILS-grid in vegetation monitoring. 
MaxNDVI: The maximum Normalized Difference Vegetation Index value for the vegetation plot for the snow period of the year.
n: the sample size, i.e., the number of vegetation plots sampled. 
N_vegetation_plot: Mean nitrogen concentration of sampled vegetation at a sampling plot, as g N per kg of dry mass vegetation.
P_vegetation_plot: Mean phosphorus concentration of sampled vegetation at a sampling plot, as g P per kg of dry mass vegetation.
N_vegetation_per_m2: Mean nitrogen concentration of sampled vegetation, as g N per square meter.
P_vegetation_per_m2: Mean phosphorus concentration of sampled vegetation, as g P per square meter.

Additional information is given in the publication. Additional questions about vegetation data can be answered by responsible NILS-staff at the Swedish University of Agricultural Sciences.


