community patterns

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

Core Site Grid Quadrat Data for the Net Primary Production Study at the Sevilleta National Wildlife Refuge, New Mexico (2013- present)

Abstract: 

Begun in spring 2013, this project is part of a long-term study at the Sevilleta LTER measuring net primary production (NPP) across three distinct ecosystems: creosote-dominant shrubland (Site C), black grama-dominant grassland (Site G), and blue grama-dominant grassland (Site B). Net primary production is a fundamental ecological variable that quantifies rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses to a range of ecological processes.

Above-ground net primary production is the change in plant biomass, represented by stems, flowers, fruit and and foliage, over time and incoporates growth as well as loss to death and decomposition. To measure this change the vegetation variables in this dataset, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at permanent 1m x 1m plots within each site. A third sampling at Site C is performed in the winter. The data from these plots is used to build regressions correlating biomass and volume via weights of select harvested species obtained in SEV999, "Net Primary Productivity (NPP) Weight Data." This biomass data is included in SEV999, "Seasonal Biomass and Seasonal and Annual NPP for Core Grid Research Sites."

Data set ID: 

289

Additional Project roles: 

450
451
452
453

Keywords: 

Methods: 

Sampling Quadrats:

Each sampling grid contains 40 1x1m quadrats in a 5x8 array. However, only 30 quadrats are sampled at each. These are quadrats 1-15 and 26-40. Thus, the middle two rows (i.e., 10 quadrats) are not sampled. Locating the Sampling Quadrats: Three core sites (B, G, and C) contain five rodent trapping and vegetation sampling webs. The vegetation grids are near these webs at each core site. At the blue grama site, the grid is located at the southern end of web 5, between webs 2 and 4. At the creosote site, the grid is east of web 3, near the road. At the black grama site, the grid is just northeast of web 5.

Collecting the Data:

Net primary production data is collected twice each year, spring and fall, for all sites. The Five Points Creosote Core Site is also sampled in winter. Spring measurements are taken in April or May when shrubs and spring annuals have reached peak biomass. Fall measurements are taken in either September or October when summer annuals have reached peak biomass but prior to killing frosts. Winter measurements are taken in February before the onset of spring growth.

Vegetation data is collected on a palm top computer. A 1-m2 PVC-frame is placed over the fiberglass stakes that mark the diagonal corners of each quadrat. When measuring cover it is important to stay centered over the vegetation in the quadrat to prevent errors caused by angle of view (parallax). Each PVC-frame is divided into 100 squares with nylon string. The dimensions of each square are 10cm x 10cm and represent 1 percent of the total area.

The cover (area) and height of each individual live (green) vegetative unit that falls within the one square meter quadrat is measured. A vegetative unit consists of an individual size class (as defined by a unique cover and height) of a particular species within a quadrat. Cover is quantified by counting the number of 10cm x 10cm squares filled by each vegetative unit.

Niners and plexidecs are additional tools that help accurately determine the cover a vegetative unit. A niner is a small, hand-held PVC frame that can be used to measure canopies. Like the larger PVC frame it is divided into 10cm x 10cm squares, each square representing 1% of the total cover. However, there are only nine squares within the frame, hence the name “niner.” A plexidec can help determine the cover of vegetative units with covers less than 1%. Plexidecs are clear plastic squares that are held above vegetation. Each plexidec represents a cover of 0.5% and has smaller dimensions etched onto the surface that correspond to 0.01%, 0.05%, 0.1%, and 0.25% cover.

It is extremely important that cover and height measurements remain consistent over time to ensure that regressions based on this data remain valid. Field crew members should calibrate with each other to ensure that observer bias does not influence data collection.

Cover Measurements:

Grasses-To determine the cover of a grass clump, envision a perimeter around the central mass or densest portion of the plant, excluding individual long leaves, wispy ends, or more open upper regions of the plant. Live foliage is frequently mixed with dead foliage in grass clumps and this must be kept in mind during measurement as our goal is to measure only plant biomass for the current season. In general, recently dead foliage is yellow and dead foliage is gray. Within reason, try to include only yellow or green portions of the plant in cover measurement while excluding portions of the plant that are gray. This is particularly important for measurements made in the winter when there is little or no green foliage present. In winter, sometimes measurements will be based mainly on yellow foliage. Stoloniferous stems of grasses that are not rooted should be ignored. If a stem is rooted it should be recorded as a separate observation from the parent plant.

Forbs, shrubs and sub-shrubs (non-creosote)-The cover of forbs, shrubs and sub-shrubs is measured as the horizontal area of the plant. If the species is an annual it is acceptable to include the inflorescence in this measurement if it increases cover. If the species is a perennial, do not include the inflorescence as part of the cover measurement. Measure all foliage that was produced during the current season, including any recently dead (yellow) foliage. Avoid measuring gray foliage that died in a previous season.

Cacti-For cacti that consist of a series of pads or jointed stems (Opuntia phaecanthaOpuntia imbricata) measure the length and width of each pad to the nearest cm instead of cover and height. Cacti that occur as a dense ball/clump of stems (Opuntia leptocaulis) are measured using the same protocol as shrubs. Pincushion or hedgehog cacti (Escobaria viviparaSchlerocactus intertextusEchinocereus fendleri) that occur as single (or clustered) cylindrical stems are measured as a single cover.

Yuccas-Make separate observations for the leaves and caudex (thick basal stem). Break the observations into sections of leaves that are approximately the same height and record the cover as the perimeter around this group of leaf blades. The caudex is measured as a single cover. The thick leaves of yuccas make it difficult to make a cover measurement by centering yourself over the caudex of the plant. The cover of the caudex may be estimated by holding a niner next to it or using a tape measure to measure to approximate the area.

Height Measurements:

Height is recorded as a whole number in centimeters. All heights are vertical heights but they are not necessarily perpendicular to the ground if the ground is sloping.

Annual grasses and all forbs-Measure the height from the base of the plant to the top of the inflorescence (if present). Otherwise, measure to the top of the green foliage.

Perennial grasses-Measure the height from the base of the plant to the top of the live green foliage. Do not include the inflorescence in the height measurement. The presence of live green foliage may be difficult to see in the winter. Check carefully at the base of the plant for the presence of green foliage. If none is found it may be necessary to pull the leaf sheaths off of several plants outside the quadrat. From this you may be able to make some observations about where green foliage is likely to occur.

Perennial shrubs and sub-shrubs (non-creosote)-Measure the height from the base of the green foliage to the top of the green foliage, ignoring all bare stems. Do not measure to the ground unless the foliage reaches the ground.

Plants rooted outside but hanging into a quadrat-Do not measure the height from the ground. Measure only the height of the portion of the plant that is within the quadrat.

Creosote Measurements till 2013:

To measure creosote (i.e., Larrea tridenta) break the observations into two categories:

1.)Small, individual clusters of foliage on a branch (i.e., branch systems): Measure the horizontal cover of each live (i.e., green) foliage cluster, ignoring small open spaces (keeping in mind the 15% guideline stated above). Then measure the vertical "height" of each cluster from the top of the foliage to a plane created by extending a line horizontally from the bottom of the foliage. Each individual foliage cluster within a bush is considered a separate observation.

2.) Stems: Measure the length of each stem from the base to the beginning of live (i.e., green) foliage. Calculate the cumulative total of all stem measurements. This value is entered under "height" with the species as "stem" for each quadrat containing creosote. All other variable receive a default entry of "1" for creosote stem measurements. Do not measure dead stems or areas of dead foliage. If in doubt about whether a stem is alive, scrape the stem with your fingernail and check for the presence of green cambium.

Creosote Measurements 2013 and after:

Each creosote is only measured as one total cover. Each quad that contains creosote will have one cover observation for each creosote canopy in quad.

Recording the Data:

Excel spreadsheets are used for data entry and file names should begin with the overall study (npp), followed by the date (mm.dd.yy) and the initials of the recorder (.abc). Finally, "g" for "grid," along with the site abbreviation, should be added (i.e., gc, gg, gb). The final format for sites B, G, and C should be as follows: npp_core.mm.dd.yy.abgg.xls. File names should be in lowercase.

Data sources: 

sev289_nppgridquadrat_20161214.csv

Additional information: 

Other researchers involved with collecting samples/data: Chandra Tucker (CAT; 04/2014-present), Megan McClung (MAM; 04/2013-present), Stephanie Baker (SRB; 2013-present), John Mulhouse (JMM; 08/2009-06/2013).

Small Mammal Exclosure Study (SMES) Rabbit Feces Data from Chihuahuan Desert Grassland and Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (1995-2005)

Abstract: 

The purpose of this study is to determine whether or not the activities of small mammals regulate plant community structure, plant species diversity, and spatial vegetation patterns in Chihuahuan Desert shrublands and grasslands. What role if any do indigenous small mammal consumers have in maintaining desertified landscapes in the Chihuahuan Desert? Additionally, how do the effects of small mammals interact with changing climate to affect vegetation patterns over time?

This is data for numbers rabbit fecal pellets counted on each of the Small Mammal Exclosure Study (SMES) plots. Rabbit fecal pellets were counted from each of the 36 one-meter2 quadrats twice each year when vegetation was measured.

Data set ID: 

91

Core Areas: 

Keywords: 

Purpose: 

The purpose of this study is to determine whether or not the activities of small mammals regulate plant community structure, plant species diversity, and spatial vegetation patterns in Chihuahuan Desert shrublands and grasslands. What role if any do indigenous small mammal consumers have in maintaining desertified landscapes in the Chihuahuan Desert? Additionally, how do the effects of small mammals interact with changing climate to affect vegetation patterns over time? This study will provide long-term experimental tests of the roles of consumers on ecosystem pattern and process across a latitudinal climate gradient. The following questions or hypotheses will be addressed.

1) Do small mammals influence patterns of plant species composition and diversity, vegetation structure, and spatial patterns of vegetation canopy cover and biomass in Chihuahuan Desert shrublands and grasslands? Are small mammals keystone species that determine plant species composition and physiognomy of Chihuahuan Desert communities? Do small mammals have a significant role in maintaining the existence of shrub islands and spatial heterogeneity of creosotebush shrub communities?  

2) Do small mammals affect the taxonomic composition and spatial pattern of vegetation similarly or differently in grassland communities as compared to shrub communities? How do patterns compare between grassland and shrubland sites, and how do these relatively small scale patterns relate to overall landscape vegetation patterns?

3) Do small mammals interact with short-term (annual) and  long-term (decades) climate change to affect temporal changes in vegetation spatial patterns and species composition?

4) Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundance’s of other consumers such as ants and grasshoppers?

Data sources: 

sev091_smesrabbit_20160308.csv

Methods: 

Experimental Design: 

There are 2 study sites, the Five Points grassland site, and the Rio Salado creosotebush site. Each study site is 1 km by 0.5 km in area. Three rodent trapping webs and four replicate experimental blocks of plots are randomly located at each study site to measure vegetation responses to the exclusion of small mammals. Each block of plots is 96 meters on each side. Each block of plots consists of 4 experimental study plots, each occupying 1/4 of each block. The blocks of study plots are all oriented on a site in a X/Y coordinate system, with the top to the north. Treatments within each block include one unfenced control plot (Treatment: C), one plot fenced with hardware cloth and poultry wire to exclude rodents and rabbits (Treatment: R), and one plot fenced only with poultry wire to exclude rabbits (Treatment: L). The three treatments were randomly assigned to each of the four possible plots in each block independently, and their arrangements differ from block to block. Each of the three plots in a replicate block are separated by 20 meters. 

Each experimental measurement plot measures 36 meters by 36 meters. A grid of 36 sampling points are positioned at 5.8-meter intervals on a systematically located 6 by 6 point grid within each plot. A permanent one-meter by one-meter vegetation measurement quadrat is located at each of the 36 points. The 36 quadrats are numbered 1-36, starting with number 1 in the top left corner (north-west) of each plot (top being north), and running left (west) to right (east), then down (south) one row, and then right (east) to left (west), and so on Quadrat/rebar number one is in the northwest corner of each plot, and numbers 1-6 are across the north side of the plot west to east, then quadrat/rebar number 7 is just south of quadrat/rebar number 6, and rebar numbers increase 7-12 east to west, and so on. 3-inch nails were originally placed in the top left (north-west) corner of each quadrat. These may be difficult to see. A 3-meter wide buffer area is situated between the grid of 36 points and the perimeter of each plot.

While measuring vegetation on each quad, the total number of rabbit feces (pellets) that  were see on each quadrat was counted and recorded.

Maintenance: 

07/07/03  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using periods (.), duplicates of data points were removed, and errors were corrected.  If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Removed Species, Comments, and Per fields.  Tape field was changed to ID# and observations made in the Per field were moved to the new ID# field.  No observations were made in the tape field.  EC field was added and NA was recorded in this field for this year.  Date MM/DD/YY field was changed to just DATE.  Other changes in the fields include PLT to PLOT, BLK to BLOCK, and CNT to COUNT. 

- Missing all Plots for Block 1 at the Grassland site for the spring except BLOCK 1 PLOT 1 TRT L.  Other Plots that are missing are Site G Block 2 Plot 3 Treatment C, Site G Block 3 Plot 3 Treatment R, and Site G Block 4 Plot 2 Treatment C. These plots are from the spring field season.  All plots are present for the fall, but with several data points missing.

-Missing plots are Site G Block 1 Plot 2 Treatment R and Site G Block 2 Plot 1 Treatment L.  These plots are from the fall field season.  All plots are present for spring field season. 

- Any empty cells were filled in with either a period for missing data or an NA for not applicable.

- Quads 32-36 were originally classified as Trt C in the fall at the Creosote site for Blk 3 Plt 2.  Changed the Trt to Trt R.

- Quads 10-16 were originally classified as TRT C in the fall at the Grass Site for BLOCK 4 PLOT 1.  Changed the TRT to TRT R.

- For the fall field season at the Grass Site, BLOCK 2 PLOT 4 TRT R QUAD 7 was classified as Creosote, changed to Grass Site. 

- Quads 21-24 were originally classified as Trt C in the spring at the Grass site for Blk 4 Plt 3.  Changed the Trt to Trt L.

- Quads 10-17 were originally classified as TRT C in the spring at the Creosote Site for BLOCK 2 PLOT 2, changed the TRT to TRT L.

- Spring Field Season Changes

For BLOCK 1 PLOT 2 TRT R and BLOCK 2 PLOT 1 TRT L all quads classified as Creosote Site, changed to Grass Site.

For quads 1-18 at the Creosote Site for BLOCK 2 PLOT 1 TRT C, originally classified as PLOT 4, changed to PLOT 1.

For Creosote Site BLOCK 4 PLOT 2 TRT C: Quads 1-4, 28-35 originally PLOT 1 changed to PLOT 2 Quads 5-19 originally PLOT 3 changed to PLOT 2

- Fall Field Season Changes

For quads 1-18 at the Creosote Site for BLOCK 1 PLOT 4 TRT R, originally classified as PLOT 3, changed to PLOT 4.

- Spring Field Season Changes

For Grass Site BLOCK 1 PLOT 4 TRT C Quads 1-30, originally classified as BLOCK 2, changed to BLOCK 1.

For Grass Site BLOCK 3 PLOT 4 TRT C Quads 20-36, originally classified as BLOCK 4 PLOT 3, changed to BLOCK 3 PLOT 4.  

- Fall Field Season Changes

For Creosote Site BLOCK 2 PLOT 2 TRT L, date changed from 10/09/00 to 11/09/00 for quads 26-36.

For Grass Site BLOCK 1 PLOT 4 TRT C, date changed from 10/06/00 to 11/06/00 for quads 23-29.    

 - Any empty cells were filled in with either a period for missing data or an NA for not applicable.

 - Terri Koontz

07/14/03  - Modified metadata to correct format.

- Terri Koontz

07/21/03  - Spring Field Season Changes

For Grass Site BLOCK 2 PLOT 1 TRT L, there were two observations for some quads that had different dates (05/02/95, 05/03/95, and 05/04/95).  All data points with either 05/02/95 or 05/03/95 were changed to BLOCK 1 PLOT 1 TRT L.  This was done because one other plot for BLOCK 2 had some quads with this same date.  Also, it seemed logical that BLOCK 1 would have been measured first.

- Terri Koontz

07/29/03  – For fall at the Grass Site BLOCK 1 PLOT 4 TRT C QUADS 10-18 had double observations.  For one set of observations, the BLOCK was changed to BLOCK 3.  This was determined by looking at another year for vegetation data to see which set had similar values and species composition for BLOCK 3.

 - Terri Koontz

07/30/03  - Quads 11-14 were originally classified as TRT C in the spring at the Creosote Site for BLOCK 3 PLOT 4, changed TRT to TRT L.

- Terri Koontz

07/22/03  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using periods (.), duplicates of data points were removed, and errors were corrected.  If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE.

- Fall Field Season Changes

Changed dates to reflect that data was measured in 2001 and not in the 1970s.

Changed in the ID# field ‘1’ to SMESVQF01CR1, ‘2’ to SMESVQF01CR2, and ‘3’ to SMESVQF01CR3.

For Creosote BLOCK 2 PLOT 3 TRT R QUADS 34 and 36, originally BLOCK 1 PLOT 3 TRT R, changed BLOCK 1 to BLOCK 2. 

For Grass BLOCK 3 PLOT 4 TRT C, originally recorded as Creosote Site, changed to Grass Site.

For Grass BLOCK 4 PLOT 2 TRT C, originally recorded as Creosote Site, changed to Grass Site.

- Any empty cells were filled in with either a period for missing data or an NA for not applicable.

- Terri Koontz

03/14/06  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK.

- Changed dates to reflect that data was measured in 2002 and not in the 1970s.

- Changed to "1" in the EC field with comments.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

03/15/06  - For the Spring field season at the Creosote site, Plots missing are BLK 1 Plot 1 Trt C and BLK 3 Plot 3 Trt C. These plots are added to the dataset as missing values.

- Metadata was modified to correct format.

- Yang Xia

03/23/06  - changed start date from september 1995 to May 1995 in the research Hypotheses, since the data collection was starting on 05/02/95. 

- Yang Xia

05/02/06  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK.

- Changed dates to reflect that data was measured in 2003 and not in the 1970s. for the data of measured in August, changed to October. 

- Changed to "1" in the EC field with comments.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

06/12/06  - Checked data for missing data points, doubles, and errors.  Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK.

- Changed dates to reflect that data was measured in 2004 and not in the 1970s and 1990s. 

- Changed to "1" in the EC field with comments.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

06/14/06  - Modified metadata to correct format.

- For Creosote Site in the Spring, changed BLOCK 4 PLOT 1 TRT C QUAD 17-21 to BLOCK 4 PLOT 1 TRL L QUAD 17-21.

- For Grassland in the Spring, changed BLOCK 4 PLOT 1 TRT C QUAD 31-36 TO BLOCK 4 PLOT 1 TRT R QUAD 31-36.

- Yang Xia

06/26/06  - Checked data for missing data points, doubles, and errors. Missing data points were recorded using -999 (human Error), duplicates of data points were removed, and errors were corrected. If a data point contained a measurement of zero and a measurement with a count, the zero observation was removed.

- Date MM/DD/YY field was changed to just DATE. BLOCK field was changed to BLK. Tapeid was changed ID #.

- Any empty cells were filled in with -999 (human Error) for missing data or an NA for not applicable.

- Yang Xia

07/03/06  - Modified metadata to correct format. 

- An NA for not applicable in the EC field for 2005.

- Yang Xia

Additional information: 

Additional Information on the personnel associated with the Data Collection / Data Processing

Sevilleta Field Crew Employee History

Megan McClung, April 2013-present, Stephanie Baker, October 2010-Present, John Mulhouse, August 2009-Present, Amaris Swann, August 25, 2008-January 2013, Maya Kapoor, August 9, 2003-January 21, 2005 and April 2010-March 2011, Terri Koontz, February 2000-August 2003 and August 2006-August 2010, Yang Xia, January 31, 2005-April 2009, Karen Wetherill, February 7, 2000-August 2009, Michell Thomey, September 3, 2005-August 2008, Jay McLeod, January 2006-August 2006, Charity Hall, January 31, 2005-January 3, 2006, Tessa Edelen, August 15, 2004-August 15, 2005, Seth Munson, September 9, 2002-June 2004, Caleb Hickman, September 9, 2002-November 15, 2004, Heather Simpson, August 2000-August 2002, Chris Roberts, September 2001-August 2002, Mike Friggens, 1999-September 2001, Shana Penington, February 2000-August 2000.

Burn Study Sites Quadrat Data for the Net Primary Production Study at the Sevilleta National Wildlife Refuge, New Mexico (2004-present)

Abstract: 

In 2003, the U.S. Fish and Wildlife Service conducted a prescribed burn over a large part of the northeastern corner of the Sevilleta National Wildlife Refuge. Following this burn, a study was designed to look at the effect of fire on above-ground net primary productivity (ANPP) (i.e., the change in plant biomass, represented by stems, flowers, fruit and foliage, over time) within three different vegetation types: mixed grass (MG), mixed shrub (MS) and black grama (G). Forty permanent 1m x 1m plots were installed in both burned and unburned (i.e., control) sections of each habitat type. The core black grama site included in SEV129 is used as a G control site for analyses and does not appear in this dataset. The MG control site caught fire unexpectedly in the fall of 2009 and some plots were subsequently moved to the south. For details of how the fire affected plot placement, see Methods below. In spring 2010, sampling of plots 16-25 was discontinued at the MG (burned and control) and G (burned treatment only) sites, reducing the number of sampled plots to 30 at each.

To measure ANPP (i.e., the change in plant biomass, represented by stems, flowers, fruit and foliage, over time), the vegetation variables in this dataset, including species composition and the cover and height of individuals, are sampled twice yearly (spring and fall) at each plot. The data from these plots is used to build regressions correlating biomass and volume via weights of select harvested species obtained in SEV157, "Net Primary Productivity (NPP) Weight Data." This biomass data is included in SEV185, "Burn Study Sites Seasonal Biomass and Seasonal and Annual NPP Data."

Core Areas: 

Data set ID: 

156

Additional Project roles: 

438
439
440
441

Keywords: 

Data sources: 

sev156_nppburnquadrat_20161214.csv

Methods: 

Collecting the Data:

Net primary production data is collected three times each year, winter, spring, and fall, for all burn sites. Spring measurements are taken in April or May when shrubs and spring annuals have reached peak biomass. Fall measurements are taken in either September or October when summer annuals have reached peak biomass but prior to killing frosts. Winter measurements are taken in February before the onset of spring growth and only creosote is measured.

Vegetation data is collected on a palm top computer. A 1-m2 PVC-frame is placed over the fiberglass stakes that mark the diagonal corners of each quadrat. When measuring cover it is important to stay centered over the vegetation in the quadrat to prevent errors caused by angle of view (parallax). Each PVC-frame is divided into 100 squares with nylon string. The dimensions of each square are 10cm x 10cm and represent 1 percent of the total area.

The cover (area) and height of each individual live (green) vegetative unit that falls within the one square meter quadrat is measured. A vegetative unit consists of an individual size class (as defined by a unique cover and height) of a particular species within a quadrat. Cover is quantified by counting the number of 10cm x 10cm squares filled by each vegetative unit. It is possible to obtain a total percent cover greater than 100% for a given quadrat because vegetative units for different species often overlap.

Niners and plexidecs are additional tools that can help accurately determine the cover a vegetative unit. A niner is a small, hand-held PVC frame that can be used to measure canopies. Like the larger PVC frame it is divided into 10cm x 10cm squares, each square representing 1% of the total cover. However, there are only nine squares within the frame, hence the name “niner.” A plexidec can help determine the cover of vegetative units with covers less than 1%. Plexidecs are clear plastic squares that are held above vegetation. Each plexidec represents a cover of 0.5% and has smaller dimensions etched onto the surface that correspond to 0.01%, 0.05%, 0.1%, and 0.25% cover.

It is extremely important that cover and height measurements remain consistent over time to ensure that regressions based on this data remain valid. Field crew members should calibrate with each other to ensure that observer bias does not influence data collection

Cover Measurements:

Grasses-To determine the cover of a grass clump, envision a perimeter around the central mass or densest portion of the plant, excluding individual long leaves, wispy ends, or more open upper regions of the plant. Live foliage is frequently mixed with dead foliage in grass clumps and this must be kept in mind during measurement as our goal is to measure only plant biomass for the current season. In general, recently dead foliage is yellow and dead foliage is gray. Within reason, try to include only yellow or green portions of the plant in cover measurement while excluding portions of the plant that are gray. This is particularly important for measurements made in the winter when there is little or no green foliage present. In winter, sometimes measurements will be based mainly on yellow foliage. Stoloniferous stems of grasses that are not rooted should be ignored. If a stem is rooted it should be recorded as a separate observation from the parent plant.

Forbs, shrubs and sub-shrubs (non-creosote)-The cover of forbs, shrubs and sub-shrubs is measured as the horizontal area of the plant. If the species is an annual it is acceptable to include the inflorescence in this measurement if it increases cover. If the species is a perennial, do not include the inflorescence as part of the cover measurement. Measure all foliage that was produced during the current season, including any recently dead (yellow) foliage. Avoid measuring gray foliage that died in a previous season.

Cacti-For cacti that consist of a series of pads or jointed stems (Opuntia phaecantha, Opuntia imbricata) measure the length and width of each pad to the nearest centimeter instead of cover and height. Cacti that occur as a dense ball/clump of stems (Opuntia leptocaulis) are measured using the same protocol as shrubs. Pincushion or hedgehog cacti (Escobaria vivipara, Schlerocactus intertextus, Echinocereus fendleri) that occur as single (or clustered) cylindrical stems are measured as a single cover.

Yuccas-Make separate observations for the leaves and caudex (thick basal stem). Break the observations into sections of leaves that are approximately the same height and record the cover as the perimeter around this group of leaf blades. The caudex is measured as a single cover. The thick leaves of yuccas make it difficult to make a cover measurement by centering yourself over the caudex of the plant. The cover of the caudex may be estimated by holding a niner next to it or using a tape measure to measure to approximate the area.

Height Measurements:

Height is recorded as a whole number in centimeters. All heights are vertical heights but they are not necessarily perpendicular to the ground if the ground is sloping.

Annual grasses and all forbs-Measure the height from the base of the plant to the top of the inflorescence (if present). Otherwise, measure to the top of the green foliage.

Perennial grasses-Measure the height from the base of the plant to the top of the live green foliage. Do not include the inflorescence in the height measurement. The presence of live green foliage may be difficult to see in the winter. Check carefully at the base of the plant for the presence of green foliage. If none is found it may be necessary to pull the leaf sheaths off of several plants outside the quadrat. From this you may be able to make some observations about where green foliage is likely to occur.

Perennial shrub and sub-shrubs (non-creosote)-Measure the height from the base of the green foliage to the top of the green foliage, ignoring all bare stems. Do not measure to the ground unless the foliage reaches the ground.

Plants rooted outside but hanging into a quadrat-Do not measure the height from the ground. Measure only the height of the portion of the plant that is within the quadrat.

Creosote Measurements till 2013:

To measure creosote (i.e., Larrea tridenta) break the observations into two categories:

1.) Small, individual clusters of foliage on a branch (i.e., branch systems): Measure the horizontal cover of each live (i.e., green) foliage cluster, ignoring small open spaces (keeping in mind the 15% guideline stated above). Then measure the vertical "height" of each cluster from the top of the foliage to a plane created by extending a line horizontally from the bottom of the foliage. Each individual foliage cluster within a bush is considered a separate observation.

2.) Stems: Measure the length of each stem from the base to the beginning of live (i.e., green) foliage. Calculate the cumulative total of all stem measurements. This value is entered under "height" with the species as "stem" for each quadrat containing creosote. All other variable receive a default entry of "1" for creosote stem measurements.

Do not measure dead stems or areas of dead foliage. If in doubt about whether a stem is alive, scrape the stem with your fingernail and check for the presence of green cambium.

Creosote Measurements 2013 and after:

Each creosote is only measured as one total cover. Each quad that contains creosote will have one cover observation for each creosote canopy in quad.

Recording the Data:

Excel spreadsheets are used for data entry and file names should begin with the overall study (npp), followed by the date (mm.dd.yy) and the initials of the recorder (.abc). Finally, the site abbreviation should be added (i.e., mg, ms, or g). The final format should be as follows: npp_burn.mm.dd.yy.abc.xls. File names should be in lowercase.

August 2009 Burn:

On August 4, 2009, a lightning-initiated fire began on the Sevilleta National Wildlife Refuge.  The fire reached the Mixed-Grass Unburned plots on August 5, 2009, consuming them in their entirety.  As a result, in the spring of 2010, the Mixed-Grass (MG) unburned plots were moved to a different area within Deep Well, southwest of the Warming site. 

Also, on August 4, 2009, some of the webs and quadrats within the unburned Black Grama (G) site were impacted by the fire.  Thus, webs 2 and 3 were abandoned and extra plots added to areas within webs 1, 4, and 5 that were not burned.  Changes were as follows:

Webs 1, 4, and 5: A plot was added to the northeast to compensate for the loss of all plots at webs 2 and 3.

Web 4: A plot was added to the northwest to compensate for the northern plot, which was burned.

Maintenance: 

01/13/2011-Burn NPP quad data was QA/QC'd and put in Navicat. Matadata updated and compiled from 2004-2010. The mixed-grass unburned plot was moved to the south after the original plot burned unexpectedly in the fire of August 2009. (JMM) 11/28/2009-Burn NPP quad data was QA/QC'd and put in Navicat. Metadata updated and complied from 2004-2009. Mixed-grass unburned data (Fall 2009) was not collected due to unexpected fire at Sevilleta LTER in Aug 2009. (YX) 01/14/09-Metadata updated and compiled from 2004-2008 data. As of 2007, winter measurements are longer being taken. (YX) 12/20/2008-This data was QAQC'd in MySQL. I checked for duplicates and missing quads. (YX)

Additional information: 

Other researchers involved with collecting samples/data: Chandra Tucker (CAT; 04/2014-present), Megan McClung (MAM; 04/2013-present), Stephanie Baker (SRB; 09/2010-present), John Mulhouse (JMM; 08/2010-04/2013), Amaris Swann (ALS; 08/2008-01/2013), Maya Kapoor (MLK; 08/2003-01/2005, 05/2010-03/2011), Terri Koontz (TLK; 02/2000-08/2003, 08/2006-08/2010), Yang Xia (YX; 01/2005-03/2010), Karen Wetherill (KRW; 02/2000-08/2009); Michell Thomey (MLT; 09/2005-08/2008); Seth Munson (SMM; 09/2002-06/2004), Jay McLeod (JRM; 01/2006-08/2006); Caleb Hickman (CRH; 09/2002-11/2004), Charity Hall (CLH; 01/2005-01/2006); Tessa Edelen (MTE, 08/2004-08/2005).Data updated 08/18/15: MOSQ changed to MUSQ3; ARPUP6 changed to ARPU9; SPWR changed to SPPO6; a single entry BOER changed to BOER4.

Discontinued Vegetation Line-Intercept Transects in Transition Zones at the Sevilleta National Wildlife Refuge, New Mexico (1989-1998)

Abstract: 

The line-intercept transects included in this data set have been discontinued. These transects were installed to evaluate temporal and spatial dynamics in vegetation transition zones (e.g.black grama grassland/creosote shrubland) at one centimeter resolution. Each study site originally contained four 400 m transects, representing total coverage of 1 sq km. The transects were placed along a roughly north/south azimuth. The northwestern and southwestern transects were 100 meters from the western edge of the 1 sq km study area and the northeastern and southeastern transects were 100 m from the eastern edge, providing 800 meters between the eastern and western transects. The northeastern and northwestern transects began to the north and, after an interval of 200 meters, the southeastern and northeastern transects began, terminating at the southern edge of the study area.

Ongoing line-intercept transect data for transect 1, which continues to be sampled at both Deep Well and Five Points, can be found in SEV004.

Core Areas: 

Data set ID: 

200

Additional Project roles: 

191

Keywords: 

Data sources: 

sev200_disconlineint_20160303.csv

Methods: 

Measuring the Transects: A 100 m tape was attached to permanent pieces of rebar at each of the four segments of a 400 m transect. The tape was stretched as tightly as possible to get the straightest line. Windy days were avoided as this became impossible.

Crew members worked independently, each sampling a 100 m segment simultaneously. Microcassette recorders and standard microcassettes were used to record data. At each 100m segment, the following sequence was followed:

Each species or substrate encountered along a transect was recorded at the centimeter level. The distance at which a species or substrate first crossed the tape was recorded.  Starting points only were recorded as the ending point of a species or substrate was the starting point of the next. It was also noted whether vegetation was fully alive, fully dead or a mix of both.

Maintenance: 

Changes to the data: This dataset (SEV200) includes all discontinued line-intercept transect data files. In particular, data is included from Bronco Well, Valle de la Jornada, Rio Salado and Sepultura Canyon, as well as transects 2-4 from Deep Well and Five Points.  Transect 1, season 2 data from Deep Well and Five Points in 1994 is also included (1994 was the only year that three seasons od data were collected). Otherwise, SEV004 contains transect 1 data from Deep Well and Five Points.

The data in this file has not been rigorously QA/QCed. Old metadata and individual year data can be found in: /export/db/local/htdocs/data/archive/plant/transect/data_oldformat. This data will not be available online. See the Sevilleta data manager for data and metadata in this old format.

Additional information: 

Principle investigator:
1989-1998: Milne, Bruce; Gosz, Jim

Data Manager:
1989-1992: Taugher, Kimberly
1993: Maddux, Troy; Taugher, Kimberly
1994: Maddux, Troy; Taugher, Kimberly; Chavez, Melissa
1995: Geer, Susan; Taugher, Kimberly
1996-1998: Taugher, Kimberly

Field Crew
1989: Banar, Alethea; Keller, David; Loftin, Sam; Maddux, Troy; Wolterstorff, Susan
1990: Franklin, Jennifer; Loftin, Sam; Maddux, Troy; Murillo, Michelle; Shortess, Amy;
Viers, Joran
1991: Maddux, Troy; Loftin, Sam; Viers, Joran; McGee, Kathleen; Prichard, Susan
1992: Maddux, Troy; Chavez, Melissa; Valdez, Monica; Bradley, Mike; Knight, Julie;
Collier, Anthony; Persaud, Amanda; Ortiz, Ivan
1993: Oriz, Ivan; Swanick, Raine; Taylor, Rob; Wagner, Natalie
1994: Chavez, Melissa; Bocock, Jonathan; Altenbach, Marilyn; Yanoff, Steven; East,
Micheal; Muckenhoupt, Jim; Budkovich, Pamela; Grant, Tom
1995: Geer, Susan; Smith, Richard; Carpenter, Claire; Parker, Kelli; Giese, Kristy;
Belden, Lisa; Weiss, Linda
1996: Taugher, Kimberly; Belden, Lisa; Payne, Jennifer; Monteith, Nancy; Newingham,
Beth Oldehoeft, Kim; Sexton, Jason
1997: Taugher, Kimberly; Campbell, Mariel; Conn, Rachel; Kuehner, John; Helm, Amy;
Kendall, John
1998: Kuehner, John; Frasier, Jason; Korbe, Nicole; Kroll, AJ; Hayes, Betty; Hersch, Erika

More information about when the data were collected:

Spring 1989 Summer 1989
dw 5/17/89-6/4/89 8/4/89-8/7/89
fp 6/5/89-6/12/89 8/8/89-8/9/89
sp 5/22/89-5/30/89 8/1/89-8/3/89
vj 6/13/89-6/20/89 8/10/89-8/11/89

Spring 1990 Summer 1990
All 5/23/90-6/14/90 All 8/6/90-9/5/90

Spring 1991 Summer 1991
All 5/22/91-7/12/91 All 7/22/91-8/15/91

Spring 1992 Summer 1992
All 6/3/92-6/18/92 7/28/92-8/6/92

Spring 1993 Summer 1993
dw 5/27/93-5/31/93 7/14/93-7/20/93
fp 6/4/93-6/10/93 7/22/93-7/27/93
vj 6/14/93-6/17/93 8/3/93-8/4/93
rs 6/17/93-7/9/93 8/4/93-8/10/93
bw 6/21/93-7/21/93 8/12/93-8/17/93
sp 7/6/93-7/8/93 not measured

Spring 1994 Summer1994 Fall 1994
dw 6/6/94 7/26/94 9/27/94-9/28/94
fp 6/8/94-6/9/94 8/2/94 9/29/94-10/3/94
vj 6/20/94 8/1/94-8/2/94 10/5/94
rs 5/31/94-6/3/94 7/25/94 10/6/94
bw 6/15/94-6/16/94 8/4/94 10/10/94-10/11/94
sp 6/23/94-6/27/94 8/9/94 10/13/94

Spring 1995 Fall 1995
dw 5/25/95 10/2/95
fp 5/30/95 9/26/95
vj 6/5/95 9/27/95
rs 5/23/95 9/25/95
bw 5/31/95 10/3/95
sp 6/6/95 10/4/95

Spring 1996 Fall 1996
dw 5/23/96 9/17/96
fp 5/27/96 9/19/96
vj 6/5/96 10/8/96
rs 5/29/96 9/25/96
bw 6/13/96 10/2/96
sp 6/3/96 9/30/96

Spring 1997 Fall 1997
dw 6/10/97 10/2/97
fp 6/11/97 10/8/97
vj 6/5/97 10/14/97
rs 6/12/97 10/16/97
bw 6/4/97 10/15/97
sp 7/15/97 10/22/97

Spring 1998 Fall 1998
dw 6/8/98 9/15/98
fp 6/1/98 9/17/98
vj 6/15/98 9/16/98
rs 7/8/98 9/29/98
bw 6/11/98 10/6/98
sp 6/30/98 10/8/98

The Effect of Kangaroo-Rat Activity on Plant Species Composition at the Sevilleta National Wildlife Refuge, New Mexico (1999)

Abstract: 

Our objective was to evaluate the effects of kangaroo rat mounds on species diversity and composition at a semiarid-arid grassland ecotone. We expected that source populations of plants occurring on kangaroo rat mounds have important influences on the species composition of vegetation at the landscape scale, and that these influences differ by grassland type. Our study was conducted at the Sevilleta LTER in New Mexico, where a grassland type dominated by Bouteloua gracilis, a shortgrass steppe species, and a grassland type dominated by B. eriopoda, a desert grassland species, meet to form patches across the landscape.

Four 0.4 ha plots were sampled for species diversity and composition in a regular 7m x 7m grid in each grassland type. Kangaroo rat mounds were also mapped and sampled for vegetation measures in four areas of 1.6 ha in each type. The landscape scale abundance of many subordinate species was increased significantly by populations occurring on kangaroo rat mounds in both grassland types. However, the area affected by the burrowing activity of kangaroo rats was twice as large in the B. eriopoda dominated grassland type. Furthermore, dominant plants on mounds in the B. eriopoda type were also abundant in off-mound areas whereas dominant plants on mounds in the B. gracilis type were not as abundant off-mound. These results indicate that the presence of mounds in the B. gracilis dominated type is creating islands of plant communities that are distinct from the rest of the grassland. Therefore, the occurrence of certain plant species in this grassland type may be intimately associated with the disturbance regime at this ecotone. This study demonstrates that effects of small burrowing animals may facilitate the coexistence of species at this ecotone.

Data set ID: 

169

Additional Project roles: 

225

Core Areas: 

Keywords: 

Methods: 

Experimental Design - We selected eight stands, four dominated by Bouteloua eriopoda and four by Bouteloua gracilis (stands were marked with A1, A2, A3, A4 in the data set for the Bouteloua eriopoda type, and U1, U2, U3, U4 for Bouteloua gracilis type). Study areas were selected using aerial photos to ensure that they were located in well-defined black grama- or blue grama-dominated belts.  Study areas were 126 m x 126 m in size and were placed so that they contained a randomly selected, average-sized, and recently abandoned kangaroo rat mound in the center.

Field Methods - In each patch type, we mapped all kangaroo-rat mounds and measured their size within the four 1.6 ha (126 m x 126 m) areas (total areas = 8). We classified each mound as active, recently abandoned, or old according to the level of small mammal activity. We noted the dominant and co-dominant plant species on each mound (i.e. species with at least 5% relative cover). In the center of each 1.6 ha plot, we estimated canopy cover (visual cover estimation) by species in 100 2m2 quadrats arranged in a regular 7 m x 7 m grid centered on a randomly selected and recently abandoned mound. Each grid covered a 63 m x 63 m area in the centre of the 1,6 ha stands. For each quadrat, we noted its location as being on a mound proper, at the edge of a mound, or in the off-mound vegetation.

Data sources: 

sev169_krat_03072012

Small Mammal Exclosure Study (SMES) Ant Data from Chihuahuan Desert Grassland and Shrubland at the Sevilleta National Wildlife Refuge, New Mexico (1995-2005)

Abstract: 

Animal consumers have important roles in ecosystems, determining plant species composition and structure, regulating rates of plant production and nutrients, and altering soil structure and chemistry. This is data for numbers and species of seed harvester ant nests mapped from each of the SMES study plots. Seed harvester ant nests were mapped on each of the study plots once each year in the autumn. Ant nest maps were drawn on to pre-designed plot diagrams. Each nest was located on the diagram in reference to one of the 36 vegetation quadrat marker posts. The distance from the post, direction from the post, and species name were plotted on the map diagram. Data such as total numbers of nests of each ant species, and spatial arrangement of nests, were then taken from the diagram maps. The following question was asked: Do small mammals interact with other herbivore and granivore consumers enough to affect the species composition and abundances of other consumers such as ants?

Core Areas: 

Data set ID: 

88

Additional Project roles: 

188
189

Keywords: 

Data sources: 

sev088_smesant_04102009.txt

Methods: 

Experimental Design: 

The Small Mammal Exclosure Study plots are located in a grassland and shrubland. These plots were established in 1995 to monitor the effects of indigenous small mammals on plant communities across the Chihuahuan Desert grassland and shrubland. There are four blocks distributed randomly at each site; each block contains three treatments plots: unfenced control (C), fenced with poultry wire to exclude lagomorphs (L), and fenced with hardware cloth and poultry wire to exclude rodents and lagomorphs (R).  The three treatment plots in each block are separated by 20 meters and were randomly assigned to one of the four plots for each block.  Each plot (36m x 36 m) contains 36 permanent 1 m2 subplots.  Vegetation measurements have been consistently taken on these subplots since 1995 and  in 1996 fenced exclosures were installed.

Data Collection Methods: 

Ant nests were mapped from each of the study plots once each year, in the autumn. An observer walks east to west and west to east along each of the 6 lines of rebar markers looking for ant nests. The observer locates each ant nest on a diagram of the study plot using rebar markers as reference points. The position of the nest relative to the nearest rebar was marked on the diagram as a small circle. The species of ant was noted as a 2-letter acronym, first letter of the genus, and first letter of the species, within the circle on the paper. The distance from the rebar was noted in meters, and the direction from the rebar was indicated on the diagram by a line drawn between the rebar and the nest. Ant species mapped include: all Pogonomyrmex species, Aphenogaster cockerelli, and Myrmecocystus species (non-seed harvesters). Pheidole species were not mapped.

Maintenance: 

Metadata entered into access. 7 April 2009 tlk

Quality Assurance: 

Contact David Lightfoot for QA/QC procedures. dlightfo@unm.edu

Additional information: 

Snakeweed (Gutierrezia sarothrae) Habitat Vegetation Transect Data from the Sevilleta National Wildlife Refuge, New Mexico (1996)

Abstract: 

In 1984, a research project was initiated on a relatively small disturbance patch just south of Deep Well. This disturbance was thought to be the result of an old praire dog town, probably dating back to when a nearby ranch was active, and a lot of old mammal mounds remained in the disturbed area. One of the things that made the disturbance patch particularily noticeable was the lush growth of snakeweed (Gutierrezia sarothrae) within the patch. This prompted the designation of the disturbance patch as the "snakeweed patch" or "gutierrezia patch". In addition, there was an obvious increase in bare ground and a shift in vegetation composition across the patch boundary. The dominant vegetation was not consistent around the boundary, with a marked dominance of black grama on the west side of the plot and a blue/black grama mix on the other three sides. To obtain information on the cause and/or effect of this disturbance, a survey of the soil and vegetation was performed.

In 1996, standard 100 m transects were set up parallel to the original vegetation transects and measured in a manner similar to SEV004 (Plant Line-Intercept Transects).

Data set ID: 

151

Core Areas: 

Additional Project roles: 

187

Keywords: 

Methods: 

Transect set-up - A 100 m measuring tape was affixed to the 0 meter rebar stake (north) and run to the 100 meter (south) end of each of four transects. The tape was stretched as tight as possible to get the straightest line. Windy days were avoided to prevent the tape from billowing.

Recording data - Four crew members worked independently, each doing a 100 m segment simultaneously. Microcassette recorders and standard microcassettes were used to record data. At each 100 m segment, the following sequence was followed: Each species/substrate encountered along the line and the distance at which that species/substrate crossed the tape was recorded. Starting location only was recorded as the ending point was the starting point of the next species/substrate.

Coordinates (NAD27): 

End of

Transect Transect Latitude Longitude

North 0 34 21' 1.2" 106 41' 8.3"W

100 34 20' 57.9"N 106 41' 8.6"W

East 0 34 20' 47.0"N 106 41' 1.6"W

100 34 20' 46.5"N 106 41' 5.4"W

West 0 34 20' 53.7"N 106 41' 16.3"W

100 34 20' 53.7"N 106 41' 12.4"W

GCA 0 34 20' 49.1"N 106 41' 9.2"W

100 34 20' 45.6"N 106 41' 9.2"W


Data sources: 

sev151_snakeweedtransects_01122010

Additional information: 

1996 REU's with assistance from the 1996 Field Crew.

Pinon Juniper Net Primary Production Quadrat Data from the Sevilleta National Wildlife Refuge, New Mexico: 1999-2001

Abstract: 

This three-year study at the Sevilleta LTER was designed to monitor net primary production (NPP) across two distinct ecosystems: pinon/juniper woodland (P) and juniper savannah woodland (J). Net primary production (NPP) is a fundamental ecological variable that measures rates of carbon consumption and fixation. Estimates of NPP are important in understanding energy flow at a community level as well as spatial and temporal responses of the community to a wide range of ecological processes. While measures of both below- and above-ground biomass are important in estimating NPP, this study focused on estimating above-ground biomass production (ANPP).

To measure ANPP (i.e., the change in plant biomass, represented by stems, flowers, fruit and foliage, over time), the vegetation variables in this dataset, including species composition and the cover and height of individuals, were sampled twice yearly (spring and fall) at permanent 1m x 1m plots. The data from these plots was used to build regressions correlating biomass and volume via weights of select harvested species obtained in SEV157, "Net Primary Productivity (NPP) Weight Data." In addition, volumetric measurements were obtained from permanent plots to build regressions correlating biomass and volume.

Spring measurements were taken in April or May when shrubs and spring annuals reached peak biomass. Fall measurements were taken in either September or October when summer annuals reached peak biomass but prior to killing frosts. Winter measurements were taken in February before the onset of spring growth.

Core Areas: 

Data set ID: 

187

Additional Project roles: 

36

Keywords: 

Data sources: 

sev187_pjnppquadrat_04122010

Methods: 

Collecting the Data:

Vegetation data is collected on a palm top computer. Excel spreadsheets are used for data entry and file names should begin with the overall study (npp), followed by the date (mm.dd.yy) and the initials of the recorder (.abc). Finally, the site abbreviation should be added (i.e., c, g, b, p). The final format should be as follows: npp.mm.dd.yy.abcg.xls. File names should be in lowercase.

A 1-m2 PVC-frame is placed over the fiberglass stakes that mark the diagonal corners of each quadrat. When measuring cover it is important to stay centered over the vegetation in the quadrat to prevent errors caused by angle of view (parallax). Each PVC-frame is divided into 100 squares with nylon string. The dimensions of each square are 10cm x 10cm and represent 1 percent of the total area.

The cover (area) and height of each individual live (green) vegetative unit that falls within the one square meter quadrat is measured. A vegetative unit consists of an individual size class (as defined by a unique cover and height) of a particular species within a quadrat. Cover is quantified by counting the number of 10cm x 10cm squares filled by each vegetative unit.

Niners and plexidecs are additional tools that help accurately determine the cover a vegetative unit. A niner is a small, hand-held PVC frame that can be used to measure canopies. Like the larger PVC frame it is divided into 10cm x 10cm squares, each square representing 1% of the total cover. However, there are only nine squares within the frame, hence the name “niner.” A plexidec can help determine the cover of vegetative units with covers less than 1%. Plexidecs are clear plastic squares that are held above vegetation. Each plexidec represents a cover of 0.5% and has smaller dimensions etched onto the surface that correspond to 0.01%, 0.05%, 0.1%, and 0.25% cover.

It is extremely important that cover and height measurements remain consistent over time to ensure that regressions based on this data remain valid. Field crew members should calibrate with each other to ensure that observer bias does not influence data collection.

Cover Measurements:

Grasses-To determine the cover of a grass clump, envision a perimeter around the central mass or densest portion of the plant, excluding individual long leaves, wispy ends, or more open upper regions of the plant. Live foliage is frequently mixed with dead foliage in grass clumps and this must be kept in mind during measurement as our goal is to measure only plant biomass for the current season. In general, recently dead foliage is yellow and dead foliage is gray. Within reason, try to include only yellow or green portions of the plant in cover measurement while excluding portions of the plant that are gray. This is particularly important for measurements made in the winter when there is little or no green foliage present. In winter, sometimes measurements will be based mainly on yellow foliage. Stoloniferous stems of grasses that are not rooted should be ignored. If a stem is rooted it should be recorded as a separate observation from the parent plant.

Forbs-The cover of forbs is measured as the perimeter of the densest portion of the plant. If the forb is an annual it is acceptable to include the inflorescence in this measurement. If the forb is a perennial, do not include the inflorescence as part of the cover measurement. Measure all foliage that was produced during the current season, including any recently dead (yellow) foliage. Avoid measuring gray foliage that died in a previous season.

Cacti-For cacti that consist of a series of pads or jointed stems (Opuntia phaecantha, Opuntia imbricata) measure the length and width of each pad to the nearest cm instead of cover and height. Cacti that occur as a dense ball/clump of stems (Opuntia leptocaulis) are measured using the same protocol as shrubs. Pincushion or hedgehog cacti (Escobaria vivipara, Schlerocactus intertextus, Echinocereus fendleri) that occur as single (or clustered) cylindrical stems are measured as a single cover.

Yuccas-Make separate observations for the leaves and caudex (thick basal stem). Break the observations into sections of leaves that are approximately the same height and record the cover as the perimeter around this group of leaf blades. The caudex is measured as a single cover. The thick leaves of yuccas make it difficult to make a cover measurement by centering yourself over the caudex of the plant. The cover of the caudex may be estimated by holding a niner next to it or using a tape measure to measure to approximate the area.

Height Measurements:

Height is recorded as a whole number in centimeters. All heights are vertical heights but they are not necessarily perpendicular to the ground if the ground is sloping.

Annual grasses and all forbs-Measure the height from the base of the plant to the top of the inflorescence (if present). Otherwise, measure to the top of the green foliage.

Perennial grasses-Measure the height from the base of the plant to the top of the live green foliage. Do not include the inflorescence in the height measurement. The presence of live green foliage may be difficult to see in the winter. Check carefully at the base of the plant for the presence of green foliage. If none is found it may be necessary to pull the leaf sheaths off of several plants outside the quadrat. From this you may be able to make some observations about where green foliage is likely to occur.

Perennial shrub and sub-shrubs-Measure the height from the base of the green foliage to the top of the green foliage, ignoring all bare stems. Do not measure to the ground unless the foliage reaches the ground.

Plants rooted outside but hanging into a quadrat-Do not measure the height from the ground. Measure only the height of the portion of the plant that is within the quadrat.

Foliage canopy cover:

Cover and height are recorded for all separate vegetative units that fall within an infinite vertical column that is defined by the inside edge of the PVC-frame. A vegetative unit consists of an individual species with a unique cover and height. This includes vegetation that is rooted outside of the frame but has foliage that extends into the vertical column defined by the PVC-frame.

As mentioned above, cover is quantified by counting the number or fraction of 10 cm x 10 cm squares intercepted by each vegetative unit. It is possible to obtain a total percent cover greater than 100 for a quadrat because vegetative units often overlap (especially in shrubs and succulents). For perennial plants, cover is based only on the vegetative portion of the plant (stem and leaf). For annual plants, cover is based on both vegetative and reproductive (inflorescence) portions of the plant.

If the cover of a vegetative unit is less than 1, the increments used are as follows: 0.01, 0.05, 0.1, 0.25, 0.5, and 0.75. If cover is between 1 and 5, increments of 0.5 are used and, if greater than 5, increments of 1 are used.  Finally, if the cover is greater than 15, the total canopy cover is divided into smaller units and the cover and heights of each observation measured separately. This reduces the size of harvest samples.

Maintenance: 

January 7, 2008 KRW Data from the P and J sites from 1999 to 2002 were extracted from the ongoing npp database and put in its own table in navicat. Palmtop/pj_npp. NPP data from 1999-2001 was QAQC'd in MySQL. I checked for duplicates and missing quads. These most often happened when a recorder mislabeled a particular quad. I also checked every plant code against the USDA Plants database online at http://plants.usda.gov/. All plant codes that have had nomenclature changes were updated. All previously unknown plants that have since been identified were also updated. All unknown plants that will never be identified were left in the database. All types were corrected. A list of codes not in the USDA list are that are still in the data are as follows NONE = no plants in quad, and UKFO57 = unknowns that will never be identified, UKFO80 = unknown that has not yet been identified. A list of the updates and the reason for the change are in the table below along with comments where identifications were questionable.

Additional information: 

Employee History:Mike Friggens: 1999 to September 2001, Karen Wetherill: February 7, 2000 to August 2009, Terri Koontz: February 2000 to August 2003 and August 2006 to August 2010, Shana Penington: February 2000 to August 2000, Heather Simpson: August 2000 to August 2002, Chris Roberts: September 2001 to August 2002.

Snakeweed (Gutierrezia sarothrae) Habitat Soils Data from the Sevilleta National Wildlife Refuge, New Mexico (1984)

Abstract: 

In 1984, a research project was initiated on a relatively small disturbance patch just south of Deep Well. This disturbance was thought to be the result of an old praire dog town, probably dating back to when a nearby ranch was active, and a lot of old mammal mounds remained in the disturbed area. One of the things that made the disturbance patch particularily noticeable was the lush growth of snakeweed (Gutierrezia sarothrae) within the patch. This prompted the designation of the disturbance patch as the "snakeweed patch" or "Gutierrezia patch." In addition, there was an obvious increase in bare ground and a shift in vegetation composition across the patch boundary. The dominant vegetation was not consistent around the boundary, with a marked dominance of black grama on the west side of the plot and a blue/black grama mix on the other three sides. To obtain information on the cause and/or effect of this disturbance, a survey of the soil and vegetation was performed.

Core Areas: 

Data set ID: 

150

Additional Project roles: 

103
104
105

Keywords: 

Data sources: 

sev150_snakeweedsoil_03302009

Methods: 

Sample collection - The soil samples were collected using a hammer-driven soil corer. The barrel of the corer was fitted with a plastic sleeve that allowed extraction of the soil core generally intact. The  soil corer was driven to a depth of 50 cm and soils split ito 10 cm fractions. This data set contains data for only the top 30 cm.

Samples were taken along six 100 m transects. Four of these transects crossed the patch boundary on the four cardinal points. On these four transects the 0m sample was taken starting 50 m outside the boundary, the 50 m sample was taken at the patch boundary and the 100 m sample was taken 50 m into the patch. The other two transects formed a cross near the center of the patch.

Twenty-one cores were collected along each transect, with increased sampling intensity near the boundary. However, this data set contains data from only the 10 m intervals for a total of 11 samples.

Sample processing - Soil samples were kept in a refrigerator prior to analysis. Each sample was weighed and samples were well-mixed before analysis. Samples were sieved through 2mm screens to remove pebbles and roots. A sample of 25 g was added to a preweighed soil can. Samples were dried for 24 hours at 105 degrees C then cooled and then reweighed. This dry/wet moisture correction was used to calibrate weights for other samples. A 1 g sample was taken from the oven-dried samples and ashed at 500 degrees C for 2 hours and re-weighed after cooling. This provided a measure of organic content. A 12 g sample was weighed into a 125 ml plastic bottle and 100 ml of 2 N KCL added before the bottles were well-shaken. After standing for 24 hours, the KCL was decanted and the samples analyzed for NO3-N and NH4-N on a Technicon Autoanalyzer. Another 5 g sample was weighed into a centrifuge tube and extracted repeatedly with pH 7 ammonium acetate. These samples were brought up to 250 ml and analyzed for Ca, Mg and K using atomic absorption. Fifty g samples of soil were mixed and texture determined using the hydrometer method. Samples were mixed 2:1 with 0.001N CaCl2 and pH measured. From the oven-dried samples 1 g samples were digested using sulfuric acid using the Kjeldahl method. Samples were then brought up to 250 ml and analyzed on a Technicon Autoanalyzer for total nitrogen and phosphorous.

Coordinates (NAD27): 

End of

Transect Transect Latitude Longitude

North 0 34 21' 1.2" 106 41' 8.3"W

100 34 20' 57.9"N 106 41' 8.6"W

East 0 34 20' 47.0"N 106 41' 1.6"W

100 34 20' 46.5"N 106 41' 5.4"W

West 0 34 20' 53.7"N 106 41' 16.3"W

100 34 20' 53.7"N 106 41' 12.4"W

GCSA 0 34 20' 49.1"N 106 41' 9.2"W

100 34 20' 45.6"N 106 41' 9.2"W

GCSB 0 34 20' 47.1"N 106 41' 8.9"W

100 34 20' 47.4"N 106 41' 5.1"W

Maintenance: 

12/10/00 (DM) File created.2/10/2009. (DM) Metadata was updated and compiled.

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