air temperature

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Soil Temperature, Moisture, and Carbon Dioxide Data from the Sevilleta National Wildlife Refuge, New Mexico (2011 - present)

Abstract: 

Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Niño frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental drivers on grassland community composition, aboveground net primary production and soil respiration. The focus is on the response of two dominant grasses (Bouteloua gracilis and B eriopoda), in an ecotone near their range margins and thus these species may be particularly susceptible to global environmental change.

It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen availability, species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics and ecosystem processes. This dataset shows values of soil moisture, soil temperature, and the CO2 flux of the amount of CO2 that has moved from soil to air.

On 4 August 2009 lightning ignited a ~3300 ha wildfire that burned through the experiment and its surroundings. Because desert grassland fires are patchy, not all of the replicate plots burned in the wildfire. Therefore, seven days after the wildfire was extinguished, the Sevilleta NWR Fire Crew thoroughly burned the remaining plots allowing us to assess experimentally the effects of interactions among multiple global change presses and a pulse disturbance on post-fire grassland dynamics.

Core Areas: 

Data set ID: 

305

Keywords: 

Methods: 

Experimental Design

Our experimental design consists of three fully crossed factors (warming, increased winter precipitation, and N addition) in a completely randomized design, for a total of eight treatment combinations, with five replicates of each treatment combination, for a total of 40 plots. Each plot is 3 x 3.5 m. All plots contain B. eriopoda, B. gracilis and G. sarothrae. Our nighttime warming treatment is imposed using lightweight aluminum fabric shelters (mounted on rollers similar to a window shade) that are drawn across the warming plots each night to trap outgoing longwave radiation. The dataloggers controlling shelter movements are programmed to retract the shelters on nights when wind speeds exceed a threshold value (to prevent damage to shelters) and when rain is detected by a rain gauge or snow is detected by a leaf wetness sensor (to prevent an unintended rainout effect).

Each winter we impose an El Nino-like rainfall regime (50% increase over long-term average for non-El Nino years) using an irrigation system and RO water. El Nino rains are added in 6 experimental storm events that mimic actual El Nino winter-storm event size and frequency. During El Nino years we use ambient rainfall and do not impose experimental rainfall events. For N deposition, we add 2.0 g m-2 y-1 of N in the form of NH4NO3 because NH4 and NO3 contribute approximately equally to N deposition at SNWR (57% NH4 and 43% NO3; Bez et al., 2007). The NH4NO3 is dissolved in 12 liters of deionized water, equivalent to a 1 mm rainfall event, and applied with a backpack sprayer prior to the summer monsoon. Control plots receive the same amount of deionized water.

Soil Measurements

Soil temperature is measured with Campbell Scientific CS107 temperature probes buried at 2 and 8 cm In the soil. Soil volume water content, measured with Campbell Scientific CS616 TDR probes is an integrated measure of soil water availability from 0-15 cm deep in the soil. Soil CO2 is measured with Vaisala GM222 solid state CO2 sensors. For each plot, soil sensors are placed under the canopy of B. eriopoda at three depths: 2, 8, and 16 cm. Measurements are recorded every 15 minutes.

CO2 fluxes are calculated using the CO2, temperature, and moisture data, along with ancillary variables following the methods of Vargas et al (2012) Global Change Biology

Values of CO2 concentration are corrected for temperature and pressure using the ideal gas law according to the manufacturer (Vaisala). We calculate soil respiration using the flux-gradient method (Vargas et al. 2010) based on Fick’s law of diffusion where the diffusivity of CO2 is corrected for temperature and pressure (Jones 1992) and calculated as a function of soil moisture, porosity and texture (Moldrup et al. 1999).

Data sources: 

sev305_wenndex_soiltemp_moisture_co2_2011
sev305_wenndex_soiltemp_moisture_co2_2012
sev305_wenndex_soiltemp_moisture_co2_2013
sev305_wenndex_soiltemp_moisture_co2_2014
sev305_wenndex_soiltemp_moisture_co2_2015

Instrumentation: 

Instrument Name: Solid State Soil CO2 sensor
Manufacturer: Vaisala
Model Number: GM222

Instrument Name: Temperature Probe
Manufacturer: Campbell Scientific
Model Number: CS107

Instrument Name: Water Content Reflectometer Probe
Manufacturer: Campbell Scientific
Model Number: CS616

Warming-El Nino-Nitrogen Deposition Experiment (WENNDEx): Meteorology Data (4/30/2007 - 8/5/2009)

Abstract: 

Humans are creating significant global environmental change, including shifts in climate, increased nitrogen (N) deposition, and the facilitation of species invasions. A multi-factorial field experiment is being performed in an arid grassland within the Sevilleta National Wildlife Refuge (NWR) to simulate increased nighttime temperature, higher N deposition, and heightened El Niño frequency (which increases winter precipitation by an average of 50%). The purpose of the experiment is to better understand the potential effects of environmental change on grassland community composition and the growth of introduced creosote seeds and seedlings. The focus is on the response of three dominant species, all of which are near their range margins and thus may be particularly susceptible to environmental change.

It is hypothesized that warmer summer temperatures and increased evaporation will favor growth of black grama (Bouteloua eriopoda), a desert grass, but that increased winter precipitation and/or available nitrogen will favor the growth of blue grama (Bouteloua gracilis), a shortgrass prairie species. Treatment effects on limiting resources (soil moisture, nitrogen mineralization, precipitation), species growth (photosynthetic rates, creosote shoot elongation), species abundance, and net primary production (NPP) are all being measured to determine the interactive effects of key global change drivers on arid grassland plant community dynamics.

Core Areas: 

Data set ID: 

258

Keywords: 

Data sources: 

sev258_warmingmet_03012012.txt

Methods: 


Experimental Design

Our experimental design consists of three fully crossed factors (warming, increased winter precipitation, and N addition) in a completely randomized design, for a total of eight treatment combinations, with five replicates of each treatment combination, for a total of 40 plots. Each plot is 3 x 3.5 m. All plots contain B. eriopoda, B. gracilis and G. sarothrae. Our nighttime warming treatment is imposed using lightweight aluminum fabric shelters (mounted on rollers similar to a window shade) that are drawn across the warming plots each night to trap outgoing longwave radiation. The dataloggers controlling shelter movements are programmed to retract the shelters on nights when wind speeds exceed a threshold value (to prevent damage to shelters) and when rain is detected by a rain gauge or snow is detected by a leaf wetness sensor (to prevent an unintended rainout effect).

Each winter we impose an El Nino-like rainfall regime (50% increase over long-term average for non-El Nino years) using an irrigation system and RO water. El Nino rains are added in 6 experimental storm events that mimic actual El Nino winter-storm event size and frequency. During El Nino years we use ambient rainfall and do not impose experimental rainfall events. For N deposition, we add 2.0 g m-2 y-1 of N in the form of NH4NO3 because NH4 and NO3 contribute approximately equally to N deposition at SNWR (57% NH4 and 43% NO3; Bez et al., 2007). The NH4NO3 is dissolved in 12 liters of deionized water, equivalent to a 1 mm rainfall event, and applied with a backpack sprayer prior to the summer monsoon. Control plots receive the same amount of deionized water.

Response of Larrea tridentata to a Natural Extreme Cold Event at the Sevilleta National Wildlife Refuge, New Mexico

Abstract: 

Shrub expansion into grasslands can cause abrupt changes in ecosystem processes. Creosote (Larrea tridentata) is a native shrub in warm, arid deserts of the southwestern US and has taken over C4 grasslands. A limited freeze tolerance is thought to dictate the northern boundary of creosote and the Sevilleta National Wildlife Refuge occurs near to the northern extent of creosote. Cold temperatures are known to damage creosote. In laboratory trials, temperatures of -25 for 1 hour lead to xylem damaging embolism in nearly 100% of stems and temperatures of -24 C lead to seedling death in the lab. Sevilleta LTER meteorological data from a station located within creosote shrublands indicated a low temperature of -20 C between 1999 and 2010. On February 3, 2011 temperatures hit record lows in central New Mexico, reaching -30 C at shrublands within the SNWR. To address how creosote responds to a natural extreme cold events, plots were established to monitor creosote initial response and regrowth following the cold event. Initial surveys will determine canopy death and subsequent surveys of the same individuals will allow us to determine how creosote responds to record cold temperatures.

Core Areas: 

Additional Project roles: 

45

Data set ID: 

244

Keywords: 

Methods: 

Plots were established at 6 locations across SNWR. Criteria for site selection included the presence of L. tridentata, flat terrain to limit microtopographic impacts, close proximity to existing meteorological stations, and variation in shrub density between sites. At each site, approximately 200 shrubs were evaluated within circular plots (20m in diameter) with the number of plots at each site varying in shrub density. Initial surveys to determine canopy death were conducted in early April 2011. These surveys consisted of tagging each shrub with an unique ID, estimating canopy death, and measuring maximum canopy height, maximum width and the perpendicular width to max width.

Additional information: 

Study Area 1:  

Study Area Name:  South Gate

Study Area Location: Located across the road from the met station located at South Gate.

Bounding Box:  

North Coordinate:  34.42

South Coordinate: 34.19

East Coordinate: -106.513

West Coordinate: -107.08

Study Area 2:  

Study Area Name: Microwave shrubland

Study Area Location: Located near the Microwave tower on the West side of the SNWR. Plots are located 100 to 200 m down the road just East of the tower towards Red Tank. Plots are on the West side of the road.

Bounding Box:  

North Coordinate: 34.42

South Coordinate: 34.19

East Coordinate: -106.518

West Coordinate: -107.08

Study Area 3:  

Study Area Name: BurnX shrubland site

Study Area Location: Located near Met station 52b, established near the burn enclosure (BurnX) Black Grama site.

Bounding Box:  

North Coordinate:  34.42

South Coordinate: 34.19

East Coordinate: -106.513

West Coordinate: -107.08

Meteorology Data from the Sevilleta National Wildlife Refuge, New Mexico (1988- present)

Abstract: 

 This file contains hourly meteorological data that were collected from a network of 10 permanent weather stations on the Sevilleta National Wildlife Refuge.

Data set ID: 

1

Core Areas: 

Additional Project roles: 

324

Keywords: 

Purpose: 

To monitor meteorological conditions across the Sevilleta and surrounding areas through time.

Data sources: 

sev1_meteorology_1988-1995.txt
sev1_meteorology_1996-2000.txt
sev1_meteorology_2001-2005.txt
sev1_meteorology_2006-2010.txt
sev1_meteorology_2011-2015.txt

Methods: 

Sampling Design

Stations were located across the Sevilleta and surrounding areas to cover the entire spatial and elevational extent of the refuge. They were also generally located adjacent to other pertinent study locations such as plant and animal monitoring studies.

Measurement Techniques

Automated weather stations

Each weather station includes a 3 m tripod tower, on which is mounted most of the monitoring equipment. This equipment includes an enclosure housing a datalogger and power supply. On the tripod are mounted an anemometer and wind vane, a pyranometer, and a solar radiation shield that encloses a combination temperature and relative humidity sensor. Other attached sensors include: a precipitation gauge, soil temperature sensors and soil moisture potential sensors.

Instrumentation: 

* Manufacturer: Campbell Scientific Inc.* Component: Datalogger - Measurement and Control Module* Model Number CR10* Reference Manuals: CR10 Measurement and Control Module            Campbell Scientific Inc.* Manufacturer: Campbell Scientific Inc.Measurement Techniques: Automated weather stations Each weather station includes a 3 m tripod tower, on which is mounted most of the monitoring equipment. This equipment includes an enclosure housing a datalogger and power supply. On the tripod are mounted an anemometer and wind vane, a pyranometer, and a solar radiation shield that encloses a combination temperature and relative humidity sensor. Other attached sensors include: a precipitation gauge, soil temperature sensors and soil moisture potential sensors.* Component: Temperature/Relative Humidity Sensor* Model Number 207* Reference Manuals:         * Manufacturer: Campbell Scientific Inc.* Component: Temperature/Relative Humidity Sensor* Model Number HMP45C* Reference Manuals:* Manufacturer: MET-ONE* Component: Cup Anemometer* Model Number 14A* Reference Manuals:* Manufacturer: MET-ONE* Component: Wind Vane* Model Number 24A* Reference Manuals:* Manufacturer: LI-COR* Component: Pyranometer* Model Number 200SZ* Reference Manuals:* Manufacturer: Texas Electronics* Component: Rain Gauge* Model Number TE525 mm* Reference Manuals:* Manufacturer: Campbell Scientific Inc.* Component: Soil Temperature Probe* Model Number 108* Reference Manuals:    * Manufacturer: Campbell Scientific Inc.* Component: Soil Temperature Probe* Model Number 107* Reference Manuals:        * Manufacturer: Campbell Scientific Inc.* Component: Soil Moisture Block * Model Number 227* Reference Manuals:        * Manufacturer: Vaisala* Component: Barometer* Model PTB101B* Reference Manuals:       

Additional information: 

These data were collected from a network of 10 permanent weather stations on the Sevilleta National Wildlife Refuge. Station 40 has been in operation since the middle of 1987; Stations 41-44 were installed in the early part of 1989; Station 45 was put into operation on 26 Jan 1990 (hour 15); Station 46 was put into operation on 31 Aug 1990 (hour 17); and Station 1 was put into test operation on 29 Dec 1991 (hr 12) and official data recording started on 01 Jan 92 (hr 01). A new station (#48) was established during 1998 (on Oct 1 1998) at a site designated as Savana (initially called Blue Springs. Station 49 was installed in the Five Points area in 1999 and named Five Points. Another new station was established in 2001 at a new core study site designated as Blue Grama and given a station ID number of 50. These data have been run through a filtering program which replaces all obviously out-of-range values with -999.000's and flags questionable values for checking by data manager.

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