LTER

U.S. Long-Term Ecological Research Network (https://www.lternet.edu)

Dataset: 

Study number: 

121

Data set ID: 

210121002

Date range: 

1998-06-29 to 1998-07-31

Original investigator: 

Laura Huenneke

Data contact: 

Abstract: 

Overview: In semiarid ecosystems the diversity of plant functional types ( grasses, shrubs, succulents, and so on) and of species may interact with the severe stresses imposed by the desert environment to influence ecosystem processes. Erosion and transport of surface sediment by wind and water is one process that may be affected by the physical structure of the plant community.

The Jornada plant diversity experiment, in which the diversity and structure of the plant community have been manipulated in large (25 m x 25 m) plots, offers the opportunity to examine the relative importance of vegetation characteristics and landscape position in determining rates of sediment movement within the plots. Each of the 48 plots of the plant diversity experiment contains 5 pans or trays on the downslope side; these accumulate sediments and plant litter that are moving within the plots (carried by wind or by water). Data have been collected on the amount of sediment accumulated in the pans during rainy and during dry seasons, with material sorted and weighed as fine (< 2 mm diameter) or coarse > 2 mm) mineral sediment, plant litter, or rabbit/jackrabbit pellets. Previous statistical analyses found that the mass of material collected per plot is explained only poorly by the treatment (plant community manipulation) of the plot and by block (a rough indication of location on the slope). Objectives: We will test the relative significance of the following variables in explaining plot-level accumulations of sediment and litter: treatment, block, position on slope (the row, from 1 (top of slope) to 10 (bottom), in which the plot is located), the treatment of the plot immediately upslope from the plot, and indices of plant cover and volume (total and by functional group) from the plot-level sampling of vegetation (using fall 1997 data). In addition, we will test the significance of the following variables in explaining the accumulation of sediment and litter in individual pans within a plot: all variables listed above for the plot, plus indices of the vegetative cover and volume located immediately upslope of the pan (weighted for distance from the pan itself). Response variables: Vegetative cover measurements are made immediately upslope of erosion pans to estimate plant cover and volume. This is done at two scales. The three large quadrats (2 m x 2 m) are used to look at all large plants (height > 25 cm) rooted within them. The six small plots (50 cm x 50 cm) are used to look at all small plants (greater or equal to 3 cm maximum diameter, but less than or equal to 10 cm) rooted within them. Maximum diameter, maximum perpendicular diameter, and height are measured to the nearest centimeter.

Data download: 

Description: 

Data file information for the following Jornada data set: Erosion zone vegetation

LTER Core Area(s): 

Dataset: 

Study number: 

9

Data set ID: 

210009001

Date range: 

1989-03-08 to 1994-12-02

Original investigator: 

David Lightfoot

Data contact: 

Abstract: 

Data for rabbits, birds, and lizards recorded from the LTER II animal transects. Data consists of species names, numbers of individuals, and distances observed from transects. Data is collected from each transect once every two weeks. See history file for exceptions.

Data for rabbits, birds, and lizards recorded from the LTER II animal transects. Data consists of species names, numbers of individuals, and distances observed from transects. Data is collected from each transect once every two weeks. See history file for exceptions.

Data download: 

Description: 

Data information for the following Jornada data set: Animal Transects

LTER Core Area(s): 

Dataset: 

Study number: 

8

Data set ID: 

210008002

Date range: 

1988-01-01 to 1994-12-31

Original investigator: 

David Lightfoot

Data contact: 

Abstract: 

Data for arthropods captured in pitfall traps on LTER II consumer plots. Data includes order, family, genus, species, and number.

Data for arthropods captured in pitfall traps on LTER II consumer plots. Data includes order, family, genus, species, and number.

Description: 

Data file information for the following Jornada data set: Arthropod Pitfall Traps-II in 4x4 grid at LTER II NPP sites

LTER Core Area(s): 

Dataset: 

Study number: 

393

Data set ID: 

210393001

Date range: 

1988-06-08 to 1988-06-30

Original investigator: 

William H Schlesinger

Data contact: 

Abstract: 

Ammonia volatilization was measured at three sites in the Chihuahuan Desert of southern New Mexico, U.S.A. In dry soils, ammonia volatilization ranged from 9 to 11 micrograms of nitrogen per square meter per day, but rates increased to 95 micrograms of nitrogen per square meter per day in a shrubland site after an experimental addition of water.

Ammonia volatilization also increased with experimental additions of NH4Cl and decreased with additions of sucrose. Competition by nitrifiers for available NH4+ had little effect on NH3 volatilization: N-Serve, added to inhibit nitrification, decreased NH3 volatilization in a grassland site and had little effect at other sites. We suggest that NH3 volatilization is controlled by the rate of mineralization of NH4+ from soil organic matter, and mineralization is stimulated by rainfall. Overall rates of NH3 volatilization from undisturbed desert ecosystems appear to be much lower than those reported for rangeland and agricultural soils.

The data set shows ammonia volatilization from grassland, cresotebush, and playa habitats in response to a variety of experimental treatments chosen to elucidate the processes controlling the volatilization under dry and post-rainfall conditions. Ammonia is collected in weak acid in scintillation vials placed inside PVC chambers in the field. The rate of ammonia volatilized per unit area ugN/m2/day) is found by mulitplying the concentration in the acid by 1250 to account for volume and area corrections.

Data download: 

Description: 

Data file information for the following Jornada data set: Ammonia volatilization from Chihuahuan Desert habitats - 1988

LTER Core Area(s): 

Dataset: 

Study number: 

393

Data set ID: 

210393002

Date range: 

1989-06-01 to 1989-06-30

Original investigator: 

William H Schlesinger

Data contact: 

Abstract: 

Ammonia volatilization was measured at three sites in the Chihuahuan Desert of southern New Mexico, U.S.A. In dry soils, ammonia volatilization ranged from 9 to 11 micrograms of nitrogen per square meter per day, but rates increased to 95 micrograms of nitrogen per square meter per day in a shrubland site after an experimental addition of water.

Ammonia volatilization also increased with experimental additions of NH4Cl and decreased with additions of sucrose. Competition by nitrifiers for available NH4+ had little effect on NH3 volatilization: N-Serve, added to inhibit nitrification, decreased NH3 volatilization in a grassland site and had little effect at other sites. We suggest that NH3 volatilization is controlled by the rate of mineralization of NH4+ from soil organic matter, and mineralization is stimulated by rainfall. Overall rates of NH3 volatilization from undisturbed desert ecosystems appear to be much lower than those reported for rangeland and agricultural soils. Data set shows ammonia volatilization from the grassland soils at the base of Mount Summerford in response to a variety of experimental treatments chosen to elucidate the processes controlling the volatilization rate. Ammonia is collected in weak acid in scintillation vials placed inside PVC chambers in the field. The rate of ammonia volatilization per unit area (ugN/m2/day) is found by multiplying the concentration in the acid by 1250.

Data download: 

Description: 

Data file information for the following Jornada data set: Nitrogen volatized as ammonia -- 1989

LTER Core Area(s): 

Dataset: 

Study number: 

369

Data set ID: 

210369002

Date range: 

1985-04-01 to 1986-04-30

Original investigator: 

David Lightfoot

Data contact: 

Abstract: 

*We conducted a field study to test the hypothesis that creosotebush (Larrea tridentata) shrubs growing in naturally nutrient-rich sites had better quality foliage and supported greater populations of foliage arthropods than shrubs growing in nutrient-poor sites. This is data for foliage arthropods sampled from Lm LVAR creosotebush shrubs. Sampling was done in April of 1985 and 1986.

Shrubs were sampled from 5 separate sites, designated A-E. 10 shrubs of 3 different selected types, random = R, high quality = H, low quality = L, were sampled at each site. Total numbers of individuals of each of the common species of foliage arthropods from each of the 30 shrubs/site are listed.

Data download: 

Description: 

Data file information for the following Jornada data set: Foliage Arthropods

LTER Core Area(s): 

Dataset: 

Study number: 

369

Data set ID: 

210369001

Date range: 

1985-04-01 to 1986-04-30

Original investigator: 

David Lightfoot

Data contact: 

Abstract: 

*We conducted a field study to test the hypothesis that creosotebush (Larrea tridentata) shrubs growing in naturally nutrient-rich sites had better quality foliage and supported greater populations of foliage arthropods than shrubs growing in nutrient-poor sites. This is data for foliage arthropods sampled from LVAR creosotebush shrubs. Sampling was done in April of 1985 and 1986.

Shrubs were sampled from 5 separate sites designated A-E. 10 shrubs of 3 different types, R=random, H=high quality, L=low quality were sampled at each site. Total numbers of taxa and individuals of each major trophic group, herbivores, predators, omnivores, from each of the 30 shrubs/site are listed.

Data download: 

Description: 

Data file information for the following Jornada data set: Arthropod Trophic Group Composition Data

LTER Core Area(s): 

Dataset: 

Study number: 

7

Data set ID: 

210007001

Date range: 

1989-01-01 to 2006-12-31

Original investigator: 

David Lightfoot

Abstract: 

In conjunction with net primary production studies, consumer and faunal studies were conducted at or near NPP sites using pitfall traps. We used live traps, not employing ethylene glycol or other killing/preservative agents, with traps checked once a week at the minimum. Sampling-with-replacement was used with the lizards.

Variables measured included species, sex, recapture status, snout-vent length, total length, weight, and whether tail was broken or whole. This study is complete.

Data download: 

Description: 

Data file information for the following Jornada data set: Lizard pitfall trap data (LTER-II, LTER-III)

Data file information for the following Jornada data set: Lizard pitfall trap data (LTER-II, LTER-III)

Data download: 

Description: 

LTER Core Area(s): 

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