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Data set status is completed, indicating that data is no longer being collected

East and west boundary fence plant line intercepts - percent cover for 9 species, Jornada Basin, 1982 to 1992

Study number: 

120

Data set ID: 

210120002

Date range: 

1982-10-08 to 1992-09-11

Original investigator: 

Walter G Whitford

Data contact: 

Abstract: 

BACKGROUND. In the spring of 1982, as part of the establishment of the Jornada Long-Term Ecological Research site in southern New Mexico, a 135 ha portion of a 1500 ha, internally drained, watershed was exclosed from grazing by domestic livestock. Prior to exclosure the watershed, as well as the rest of the Jornada basin, had been moderately to heavily grazed for the past 100 years.

Concurrent with grazing, the vegetation had undergone a dramatic change from desert grassland, with an almost continuous cover of C4 perennial grasses, to isolated patches of the original grassland in a mosaic with desert shrub dominated plant communities (Buffington and Herbel, 1965). The exclosure lies along a northeast facing piedmont slope at the base of a steep isolated mountain peak, and covers a variety of component landforms from the foot of the mountain to the basin floor. This provided the opportunity to investigate the response of vegetation with respect to landscape characteristics as well as release from grazing. This summary data set consists of percent cover of 9 species from the plant line intercept measurements on either side of the LTER-I exclosure East and West boundary fence. Data is sorted by station, species i.d., then line segment. Along the East Boundary fence, the east side is ungrazed (control) and the west side is grazed (treatment). Along the West Boundary fence, the east side is grazed and the west side is ungrazed. Each plant line transect is divided into 6 5-meter segments. All perennials were measured at about 5 year intervals as the length of intercept along a 30-meter line perpendicular to the fence. Summary data includes only four of the 6 5-meter intervals due to disturbance along fenceline. Data from the 5-meter segment on either side of the fence was not included in summarizing the data. Summary data includes only 9 of the perennial species.

Data download: 

Arthropod Pitfall Traps-III in 5x1 grid at LTER II NPP sites

Study number: 

8

Data set ID: 

2100008001

Original investigator: 

John Anderson

Abstract: 

Objectives. Desertification is hypothesized to have
altered the spatial and temporal availability of resources
required by the biota. Results of desertification on the
Jornada include changes to shrub dominated communities and
major soil changes. We hypothesize that these shifts in
vegetation have changed resources temporally for many of the

Objectives. Desertification is hypothesized to have
altered the spatial and temporal availability of resources
required by the biota. Results of desertification on the
Jornada include changes to shrub dominated communities and
major soil changes. We hypothesize that these shifts in
vegetation have changed resources temporally for many of the
consumers. If grassland systems respond to rainfall without
significant lags, but shrub systems do not, then consumer
species should reflect these differences. In addition,
shifts from grassland to shrubland results in greater
structural heterogeneity of the habitats. We have
hypothesized that consumer populations, diversity, and
densities of some consumers will be higher in grasslands
than in shrublands. Diversity and/or densities are
hypothesized to be related to the NPP of the sites. Data
will be collected for the duration of the LTER program in
order to provide data to test these hypotheses.
Data for arthropods captured in pitfall traps on LTER
III consumer plots at 2 month intervals. Data includes
order, family, genus, species, and number.

Pre-dawn water potential for leaves from 5 precipitation treatments

Study number: 

40

Data set ID: 

2100409002

Date range: 

2007-07-25 to 2008-09-20

Original investigator: 

Heather Throop

Data contact: 

Abstract: 

Data are pre-dawn water potential for leaves collected from plants subjected to five possible precipitation treatments: -80%, -50%, control (0), +50%, +80%. The objective is to assess water status of plants in response to precipitation manipulations.

Data are pre-dawn water potential for leaves collected from plants subjected to five possible precipitation treatments: -80%, -50%, control (0), +50%, +80%. The objective is to assess water status of plants in response to precipitation manipulations.

Photosynthetic rates for leaves from 5 precipitation treatments

Study number: 

40

Data set ID: 

2100409001

Date range: 

2007-07-25 to 2008-09-20

Original investigator: 

Heather Throop

Data contact: 

Abstract: 

Data are photosynthetic rates (Amax) for leaves collected from plants subjected to five possible precipitation treatments: -80%, -50%, control (0), +50%, +80%. The objective is to assess photosynthetic response of plants to precipitation manipulations.

Data are photosynthetic rates (Amax) for leaves collected from plants subjected to five possible precipitation treatments: -80%, -50%, control (0), +50%, +80%. The objective is to assess photosynthetic response of plants to precipitation manipulations.

Drought recovery gas-exchange of Larrea Tridentata

Study number: 

391

Data set ID: 

210391001

Original investigator: 

John Anderson

Abstract: 

Principal questions include: How fast do key physiological functions (CO2 assimilation, stomatal conductance, leaf water status, leaf area , PS II function) recover upon soil rewetting after drought, and in what order?

Details include: Does stomatal conductance follow the Ball-Berry model, gs = m A hs/Cs + b, with A = CO2 assimilation rate, hs, Cs = relative humidity and CO2 mixing ratio at the leaf surface, and m, b= empirical constants (but almost universally near 10 and 0 for well- watered plants of diverse species and biomes) Do the stomatal parameters vary systematically with leaf and soil water status? Does recovery depend systematically upon neighbor biomass, net soil water input per area (dependent upon topography of water distribution), and plant size? Conversely, how do the functions change on entry into drought? Initial analyses of these and allied data indicate: Leaf water potential has anomalous diurnal trend in drought, peaking in mid-morning. Also, psi(leaf) only recovers to about -2 MPa even with abundant soil water. Leaves lose apparent photosynthetic capacity (Vcmax) daily in drought; much of this is loss of PS II function as measured by chlorophll; fluorescence...but PS II function is restored nearly completely every day. Recovery may be closely tied to high dark-respiration rates seen even in intense drought. We hypothesize that continuous repair enables the shrubs to capitalize upon transient water supplies after erratic and small summer rainfalls. Stomatal conductance, gs, drops with drought and diurnally within drought episodes. However, leaf-internal CO2 concentration, Ci, is nearly unchanged and does not decrease to improve water-use efficiency. The signal for diurnal decreases in gs is not any simple measure of water status, particularly not bulk leaf water potential or soil water potential, unlike signals demonstrated in other plants to date. Mild recovery from drought (modest rainfall - ca. 10 mm total) induces recovery of photosynthetic capacity but no new leaf area in some individual plants, new leaf growth in others. in strong recoveries, both photosynthetic capacity and leaf area recover in all plants.

Arson burn on LTER-I Transect plant line intercepts - field data (tape format)

Study number: 

384

Data set ID: 

210384001

Original investigator: 

John Anderson

Abstract: 

LTER-I Transect plant line intercept data. This data set is as transcribed (UNSORTED) from cassette tape with one intercept observation per record. Data consist of week number, transect, station, segment number, plant species, and length of species intercepted by line stretched between 2 rebar the length of the 30 meter plant line intercept transect.

Measurements are made on 30-meter line intercept transects located perpendicular to each of 91 stations on each of the 2.7 km long Control, Treatment, and Alternate Control Transects established at the beginning of LTER-I. Each plant line transect is divided into 6 5-meter segments. Annuals are measured only in the first meter of segments 1, 2, and 3 and in the last meter of segments 4, 5, and 6. Perennials are measured for the full length of all segments. On March 19, 2000, an arson burn occurred of 2.5 acres of the upper grassland area on the Summerford bajada just below the powerline road. The area affected included portions of the LTER-I Transect Plant Line Intercept study that was begun in 1982. To evaluate the impact of the burn on those lines, the line intercepts were read for the upper grassland area extending from immediately above the creosotebush fringe to the base of Summerford Mountain. The stations measured were C73-C89, T75-T90, and X76-X91 (Control, Treatment, and Alternate Control, respectively). Measurements were made immediately after the burn, after the spring growing season, and after the fall growing season in 2000 only. In the initial sampling period, the burn area intercepted by the line was noted in the data set using a "species" code of BURN. BACKGROUND. In the spring of 1982, as part of the establishment of the Jornada Long-Term Ecological Research site in southern New Mexico, a 135 ha portion of a 1500 ha, internally drained, watershed was exclosed from grazing by domestic livestock. Prior to exclosure the watershed, as well as the rest of the Jornada basin, had been moderately to heavily grazed for the past 100 years. Concurrent with grazing, the vegetation had undergone a dramatic change from desert grassland, with an almost continuous cover of C4 perennial grasses, to isolated patches of the original grassland in a mosaic with desert shrub dominated plant communities (Buffington and Herbel, 1965). The exclosure lies along a northeast facing piedmont slope at the base of a steep isolated mountain peak, and covers a variety of component landforms from the foot of the mountain to the basin floor. This provided the opportunity to investigate the response of vegetation with respect to landscape characteristics as well as release from grazing.

Arson burn on LTER-I transect plant line intercepts - LT series (percent cover)

Study number: 

384

Data set ID: 

210384002

Original investigator: 

John Anderson

Abstract: 

On March 19, 2000, an arson burn occurred of 2.5 acres of the upper grassland area on the Summerford bajada just below the powerline road. The area affected included portions of the LTER-I Transect Plant Line Intercept study that was begun in 1982.

To evaluate the impact of the burn on those lines, the line intercepts were read for the upper grassland area extending from immediately above the creosotebush fringe to the base of Summerford Mountain. The stations measured were C73-C89, T75-T90, and X76-X91 (Control, Treatment, and Alternate Control, respectively). Measurements were made immediately after the burn, after the spring growing season, and after the fall growing season in 2000 only. In the initial sampling period, the burn area intercepted by the line was noted in the data set using a "species" code of BURN. Average percent coverage of each plant species per 5-meter segment along a 30-meter line intercept perpendicular to each of 91 stations on each of the three LTER-I permanent transects. Data consists of week number, transect, station number, species, carbon reduction pathway, habit, form, and average percent cover. It is sorted by transect, station number, then plant species. Measurements are made on 30-meter line intercept transects located perpendicular to each of 91 stations on each of the 2.7 km long Control, Treatment, and Alternate Control Transects established at the beginning of LTER-I. Following January 1, 1987, spring line- intercepts will only record cover of annual species. All perennial cover data will be limited to fall samples. Both annuals and perennials are measured during the fall. Measurements were made biannually from 1982 - 1988. After this they are measured every 5 years. Annuals are measured through 1998; however, after this only perennials are measured and only in the fall. Each plant line transect is divided into 6 5-meter segments. Annuals are measured only in the first meter of segments 1, 2, and 3 and in the last meter of segments 4, 5, and 6. Perennials are measured for the full length of all segments. BACKGROUND. In the spring of 1982, as part of the establishment of the Jornada Long-Term Ecological Research site in southern New Mexico, a 135 ha portion of a 1500 ha, internally drained, watershed was exclosed from grazing by domestic livestock. Prior to exclosure the watershed, as well as the rest of the Jornada basin, had been moderately to heavily grazed for the past 100 years. Concurrent with grazing, the vegetation had undergone a dramatic change from desert grassland, with an almost continuous cover of C4 perennial grasses, to isolated patches of the original grassland in a mosaic with desert shrub dominated plant communities (Buffington and Herbel, 1965). The exclosure lies along a northeast facing piedmont slope at the base of a steep isolated mountain peak, and covers a variety of component landforms from the foot of the mountain to the basin floor. This provided the opportunity to investigate the response of vegetation with respect to landscape characteristics as well as release from grazing.

Data download: 

Nutrient losses in runoff from grassland and shrubland habitats in southern New Mexico: I. Rainfall simulation experiments --SUMMARY of SHRUB nitrogen and phosphorus chemistry

Study number: 

381

Data set ID: 

210381004

Original investigator: 

John Anderson

Abstract: 

This data set was collected to provide data for comparison of the losses of dissolved nitrogen and phosphorus in the runoff from grass- and shrub- dominated plots in the Jornada Basin of southern New Mexico. This summary dataset contains the following columns for the shrub plots: Plot: the identification number for the 6 grassland plots.

Q: the mean rate of discharge during the entire experiment, obtained by dividing the total runoff by l800 sec. The units are cubic centimeters per second. Total N yield: the total yield of dissolved nitrogen discharged from the plot during the duration of the experiment. The units are grams per square meter per l800 sec. This yield has been adjusted, by subtracting the content of total dissolved N applied in the simulated rainfall. Organic N yield: the yield of dissolved organic N, as above. Inorganic N yield: the yield of NH4-N plus NO3-N discharged from the plot during the duration of the experiment, as above. Total P yield: the yield of total dissolved P discharged from the plot during the duration of the experiment. The units are grams per square meter, per l800 sec. Organic P yield: the yield of dissolved organic P, as above. Inorganic P yield: the yield of PO4-P discharged from the plot during the duration of the experiment. Fines: the percent of the plot surface covered by materials < 2.0 mm diameter Gravel: the percent of the plot surface covered by materials > 2.0 mm diameter Vegetation: the percent of the plot surface covered by vegetation. Litter: the percent of the plot surface covered by plant litter. Slope: it was not possible to measure slope in plots with a shrub in them, since the mound dominated the slope in the plot.

Nutrient losses in runoff from grassland and shrubland habitats in southern New Mexico: I. Rainfall simulation experiments --SUMMARY of INTERSHRUB nitrogen and phosphorus chemistry

Study number: 

381

Data set ID: 

210381003

Original investigator: 

John Anderson

Abstract: 

This data set was collected to provide data for comparison of the losses of dissolved nitrogen and phosphorus in the runoff from grass- and shrub- dominated plots in the Jornada Basin of southern New Mexico. This summary dataset contains the following columns for the intershrub plots: Plot: the identification number for the 6 grassland plots.

Q: the mean rate of discharge during the entire experiment, obtained by dividing the total runoff by l800 sec. The units are cubic centimeters per second. Total N yield: the total yield of dissolved nitrogen discharged from the plot during the duration of the experiment. The units are grams per square meter per l800 sec. This yield has been adjusted, by subtracting the content of total dissolved N applied in the simulated rainfall. Organic N yield: the yield of dissolved organic N, as above. Inorganic N yield: the yield of NH4-N plus NO3-N discharged from the plot during the duration of the experiment, as above. Total P yield: the yield of total dissolved P discharged from the plot during the duration of the experiment. The units are grams per square meter, per l800 sec. Organic P yield: the yield of dissolved organic P, as above. Inorganic P yield: the yield of PO4-P discharged from the plot during the duration of the experiment. Fines: the percent of the plot surface covered by materials < 2.0 mm diameter Gravel: the percent of the plot surface covered by materials > 2.0 mm diameter Vegetation: the percent of the plot surface covered by vegetation. Litter: the percent of the plot surface covered by plant litter. Slope: the plot in degrees

Nutrient losses in runoff from grassland and shrubland habitats in southern New Mexico: I. Rainfall simulation experiments --SUMMARY of GRASSLAND nitrogen and phosphorus chemistry

Study number: 

381

Data set ID: 

210381002

Original investigator: 

William H Schlesinger

Abstract: 

This data set was collected to provide data for comparison of the losses of dissolved nitrogen and phosphorus in the runoff from grass- and shrub- dominated plots in the Jornada Basin of southern New Mexico. This summary dataset contains the following columns for the grassland plots: Plot: the identification number for the 6 grassland plots.

Q: the mean rate of discharge during the entire experiment, obtained by dividing the total runoff by l800 sec. The units are cubic centimeters per second. Total N yield: the total yield of dissolved nitrogen discharged from the plot during the duration of the experiment. The units are grams per square meter per l800 sec. This yield has been adjusted, by subtracting the content of total dissolved N applied in the simulated rainfall. Organic N yield: the yield of dissolved organic N, as above. Inorganic N yield: the yield of NH4-N plus NO3-N discharged from the plot during the duration of the experiment, as above. Total P yield: the yield of total dissolved P discharged from the plot during the duration of the experiment. The units are grams per square meter, per l800 sec. Organic P yield: the yield of dissolved organic P, as above. Inorganic P yield: the yield of PO4-P discharged from the plot during the duration of the experiment. Fines: the percent of the plot surface covered by materials < 2.0 mm diameter Gravel: the percent of the plot surface covered by materials > 2.0 mm diameter Vegetation: the percent of the plot surface covered by vegetation. Litter: the percent of the plot surface covered by plant litter. Slope: the plot in degrees

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