Joseph Gaudard 2022-06-14
We study how trait composition influences ecosystem functioning by measuring CO2-flux within and across plant communities, mainly focus on ecosystem carbon dynamics in response to climate change, but also nitrogen deposition and grazing. Twenty-four hours of carbon Flux measurement was conducted along the elevational gradients in the four different sites, which are Vikesland (408 masl, 6 plots), Hogsete (697 masl, 3 plots), Joasete (888 masl, 6 plots), and Liahovden (1.267 masl, 3 plots). Net Ecosystem Exchange (NEE) and Ecosystem Respiration (ER) along with Photosynthetic Active Radiation (PAR) were measured using Li-cor LI-840A.
| Variable name | Description | Variable type | Variable range or levels | Unit | How measured |
|---|---|---|---|---|---|
| datetime | Date and time of the carbon flux measurement | date_time | 2022-07-23 21:45:15 - 2022-07-31 08:12:45 | yyyy-mm-dd hh:mm:ss | recorded |
| time | Time of the carbon flux measurement (independent of date) | NA | NA | hh:mm:ss | recorded |
| origSiteID | Unique site ID of origin site | categorical | Hogsete - Vikesland | NA | defined |
| destSiteID | Unique site ID of destination site (the site they were measured at) | categorical | Hogsete - Vikesland | NA | defined |
| turfID | Unique ID of vegetation turf as origSiteID, treatments and destSiteID | categorical | 105 WN3C 173 - TTC 146 | NA | defined |
| warming | Warming treatment with W for warming or A for ambient | categorical | A - W | NA | defined |
| type | Types of the CO2 flux data: GPP = Gross Primary Productivity, NEE = Net ecosystem exchange, and ER = ecosystem respiration | categorical | ER - NEE | NA | defined |
| fluxID | Unique identifier for each flux measurement | numeric | 1 - 288 | NA | defined |
| flux_value | Flux as calculated with the slopes. No value replaced with flags. Corrected for CO2 accumulation in canopy at night. | numeric | -141.365 - 130.504 | mmol m-2hr-1 | calculated |
| PARavg | Mean Photosynthetic Active Radiation (PAR) | numeric | -2.843 - 1840.27 | µmol s-1sqm-1 | recorded |
| temp_soil | Mean soil temperature measured during flux measurements. | numeric | 0.84 - 32.13 | °C | recorded |
| temp_airavg | Mean air temperature measured during the flux measurments. Not recommended for microclimate analyses. | numeric | 0.807 - 32.454 | °C | recorded |
| flag | Flagging missing or unreliable data. This information can be used to sort unwanted observations. | categorical | discard - zeroNEE | NA | defined |
| Variable name | Description | Variable type | Variable range or levels | Unit | How measured |
|---|---|---|---|---|---|
| datetime | Date and time of measurement | date_time | 2022-07-23 00:15:00 - 2022-08-08 | yyyy-mm-dd hh:mm:ss | recorded |
| loggerID | Unique climate logger ID | categorical | 95221106, 95221107, 95221108, 95221109, 95221110, 95221146, 95221147, 95221148, 95221149, 95221150, 94195255, 94195259, 94195218, 94195214, 94200496, 94195247, 94195237, 94200491, 94194604, 94195201, 94195202, 94195203, 94195204, 94195205, 94195206, 94195207, 94195208, 94195209, 94195210, 94195211, 94195212, 94195213, 94195215, 94195216, 94195217, 94195219, 94195220, 94195221, 94195222, 94195223, 94195224, 94195225, 94195226, 94195228, 94195229, 94195231, 94195232, 94195233, 94195234, 94195235, 94195238, 94195239, 94195240, 94195242, 94195243, 94195244, 94195245, 94195246, 94195248, 94195249, 94195250, 94195253, 94195254, 94195257, 94195258, 94195260, 94195262, 94195263, 94195264, 94195265, 94195266, 94195267, 94195268, 94195269, 94195270, 94195271, 94195272, 94200493, 94200494, 94200495, 94200497, 94200498, 94200499, 94201707 | NA | defined |
| turfID | Unique ID of vegetation turf as origSiteID, treatments and destSiteID | categorical | 100 AN5M 100 - TTC 146 | NA | defined |
| origSiteID | Unique site ID of origin site | categorical | Hogsete - Vikesland | NA | defined |
| destSiteID | Unique site ID of destination site | categorical | Hogsete - Vikesland | NA | defined |
| warming | Warming treatment with W for warming or A for ambient | categorical | A - W | NA | defined |
| datetime_in | Date and time the logger was installed or date and time the logger data should be trimmed to | date_time | 2019-08-22 23:00:00 - 2022-07-29 22:30:00 | yyyy-mm-dd hh:mm:ss | defined |
| datetime_out | Date and time the logger was removed or date and time the logger data should be trimmed to | date_time | 2022-07-28 11:00:00 - 2022-09-02 06:00:00 | yyyy-mm-dd hh:mm:ss | defined |
| climate_variable | Microclimate variable including air_temperature, ground_temperature, soil_temperature, and soil_moisture | categorical | air_temperature - soil_temperature | NA | defined |
| value | Temperature or moisture reading including values later flagged as suspect | numeric | -1 - 34.625 | °C, (m3 water × m−3 soil) × 100 | recorded |
| flag | Warning for values that exceed expected parameters | categorical | cut_min_moist - keep | NA | defined |
Note: those data are representative of a single point in the season (close to peak productivity), but not necessarily representative of the entire season or annual carbon balance.
- How is the mean and/or median comparing to the calculated 24h fluxes?
- How much is the peak measurement (usual method) deviating from the calculated 24h fluxes?
- Temperature response curves, species composition of turfs (group 3)
- SLA / LMA to explain GPP with transplant treatment (or any other proxy of biomass)
- Impacts of traits on flux through 24h
- Greater diversity leading to greater productivity? Does this hold for transplants?
- Legacy effect versus adaptation on fluxes: is the transplant behaving (fluxes wise) more similarly to the local ambient or the origin ambient?
- Fluxes related to conditions and altitude gradient:
- gradient of temperature
- gradient of PAR?? (group 3, we need answers!)
- how are those gradients affecting c fluxes? (using ambient turfs)
- or is that only an effect of the species composition?
- Soil respiration: is photosynthesis or soil respiration the main driver in variation of NEE accross the altitude gradient?
- How much are the traits explaining the variability in fluxes? Can the altitude gradient and the transplanting explain more of that variation?
- Connect the chamber to the licor and the pump.
- Place PAR sensor and air temperature in the chamber and connect them to the logger.
- Connect the battery and see that the licor is working normally (there should be a green light).
- Connect and arm the logger.
- Check that the watch you will use to write down starting time is synchronized with the logger.
- Turn on the fan and the pump.
- Check the value from the licor (should be around 400ppm).
- Check that the fan and pump are working and that all the tubes are connected.
- Check that the logger is armed.
- Air the chamber.
- Put the chamber on the inner plot and apply the chain on the skirt of the chamber for airtightness.
- Write down the exact time at which the measurement started (with a 10 seconds resolution).
- Leave it undisturbed for 3 minutes. Be careful to not move around (might push gases out of the ground) and to not shade the chamber.
- Write down when the measurement ended.
- Remove the chain and the chamber, and air the chamber.
- To save battery, you can turn off the fan and the pump in between measurements (but do not turn off the licor!)
Cover the chamber with the dark tarp before measuring and do the same as for NEE.
Air temperature and PAR values will be logged directly in the same dataset as the cflux. Soil moisture and temperature will be measured using TMS microclimate loggers.
- Let the logger and licor run 1 minute after the last measurement
- Turn off the fan and pump
- Disarm the logger.
- Disconnect everything for transport.
- Take a picture of the field data sheet.
The battery has a button that you can briefly press to see the battery state. You should change the battery when it reaches 25% (the last liht).
- Turn off the fan and pump.
- Disconnect both cables from the old battery.
- Connect the new battery (Connect the correct colors or walk down the mountain to fetch the other licor!)
- Turn on the fan and pump and check that everything works normally.
- Wait a minute before starting a new measurement.
- Turn off the fan and pump
- Disarm the logger
- Disconnect the logger
- Change the batteries
- Connect the logger
- Check the logger’s clock again
- Arm the logger