Populations

LTER Core Area: Populations

Stressor II transect line point intercept data

Study number: 

461

Data set ID: 

210461001

Date range: 

1996-02-27 to 2009-10-27

Original investigator: 

Kris Havstad

Abstract: 

The goal of this sampling effort is to describe the vegetation response to treatments.  Data were collected following the line-point intercept method (Herrick et al.

2009).  Although the original LPI data set was in multivariate form with separate columns for canopy layers and soil surface, this data set has been transposed into vertical form, implementing a “layer” variable, so that all species and soil surface codes appear in one column.  Within each exclosure, 4837 points were sampled with the following exceptions:

year

exclosure

total_points_sampled

1996

5

4825

1996

7

4836

1996

9

4836

1996

10

4836

1997

1

4830

1997

2

4830

1997

3

4830

1997

4

4830

1997

5

4830

1997

6

4830

1997

7

4830

1997

8

4830

1997

9

4830

1997

10

4830

1997

11

4830

1997

12

4830

1997

13

4830

1997

14

4830

1997

15

4830

1997

16

4830

1997

17

4830

1997

18

4830

2002

12

4835

 

Data download: 

Conmod Pilot Study: Annual vegetation transect Line Point Intercept measurements

Study number: 

308

Data set ID: 

210308002

Date range: 

2008-06-10 to 2009-07-27

Original investigator: 

Debra Peters

Abstract: 

    Line-Point Intercept data are collected annually for this project beginning in 2008. No data were
    collected in 2011. There are 4 pairs of plots consisting of control and treatment. Each plot is
    8x8 meters with an 8x8 meter buffer plot above and below it. Treatment plots have connectivity modules
    Line-Point Intercept data are collected annually for this project beginning in 2008. No data were
    collected in 2011. There are 4 pairs of plots consisting of control and treatment. Each plot is
    8x8 meters with an 8x8 meter buffer plot above and below it. Treatment plots have connectivity modules
    (conmods) installed to decrease gap size between perennials.  Buffer plots do not have conmods.
    Four 24-meter transects run through the plot and 2 buffer plots. These transects are spaced
    0.8, 2.8, 4.3, and 7.2 meters across the plots (denoted as 1, 3, 5, and 7 meters in the database),
    paralleling the long axis of the combined buffer plots and central plot.
         Aeolian site:         Control plots 2,4,5,8  Treatment plots 1,3,6,7
         Dona Ana site:        Control plots 2,4,5,7  Treatment plots 1,3,6,8
         Gravelly Ridges site: Control plots 1,3,5,7  Treatment plots 2,4,6,8
 

Data download: 

Conmod Pilot Study: Annual plant canopy gap and basal gap intercept data

Study number: 

308

Data set ID: 

210308001

Date range: 

2006-06-10 to 2009-07-11

Original investigator: 

Debra Peters

Abstract: 

Canopy Gap and Basal Gap Intercept data are collected annually for this project beginning in 2008. No data were collected in 2011. There are 4 pairs of plots consisting of control and treatment. Each plot is 8x8 meters with an 8x8 meter buffer plot above and below it. Treatment plots have connectivity modules (conmods) installed to decrease gap size between perennials. Buffer plots do not have conmods. Four 24-meter transects run through the plot and 2 buffer plots. These transects are spaced 0.8, 2.8, 4.3, and 7.2 meters across the plots (denoted as 1, 3, 5, and 7 meters in the database), paralleling the long axis of the combined buffer plots and central plot.
Aeolian site:                Control plots 2,4,5,8  Treatment plots 1,3,6,7
Dona Ana site:            Control plots 2,4,5,7  Treatment plots 1,3,6,8
Gravelly Ridges site:  Control plots 1,3,5,7  Treatment plots 2,4,6,8

Jornada Experimental Range Permanent Quadrat Chart data beginning 1915 - plant cover

Study number: 

351

Data set ID: 

2100351001

Date range: 

1915-06-01 to 2001-12-31

Original investigator: 

William Ridgely Chapline

Abstract: 

The data set, along with other long-term data collected at multiple spatial scales, is being used to identify the landscape, climatic, and anthropogenic factors that influence grass abundance, growth, and persistence. Variables measured are basal area of grasses, canopy area of shrubs, and perimeters of both.
The data set, along with other long-term data collected at multiple spatial scales, is being used to identify the landscape, climatic, and anthropogenic factors that influence grass abundance, growth, and persistence. Variables measured are basal area of grasses, canopy area of shrubs, and perimeters of both.

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.

Plant cover in precipitation and nitrogen treatment plots (by species)

Study number: 

27

Data set ID: 

2100278002

Date range: 

2006-10-01 to 2008-09-30

Original investigator: 

Lara G Reichmann

Data contact: 

Abstract: 

We use vegetation cover as a proxy for plant biomass to avoid confounding spatial and temporal variability or confounding the impact of harvesting. The rate of biomass change is Aboveground net primary production, a key variable that will respond to our PPT and nutrient manipulations.

Measured variables: individual cover of plant species measured as cm of green biomass that intercepts a 250cm long line, then averaged for 3 lines/plot.

Data download: 

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: 

Ecotone rodent metrics (abundance, biomass, energy, species richness)

Study number: 

262

Data set ID: 

210262001

Original investigator: 

Brandon Bestelmeyer

Abstract: 

OBJECTIVE: The purpose of the study is to investigate how pulses of precipitation translate
into pulses of plant above ground net primary productivity (NPP) and how the small mammal
community responds to such changes also in relation to shrub gradient across the landscape.
Particularly we are interested in how the energy flows through the ecosystem in response to

OBJECTIVE: The purpose of the study is to investigate how pulses of precipitation translate
into pulses of plant above ground net primary productivity (NPP) and how the small mammal
community responds to such changes also in relation to shrub gradient across the landscape.
Particularly we are interested in how the energy flows through the ecosystem in response to
pulses of rain.

HYPOTHESES:
1) Small mammal abundance should respond positively to precipitation and NPP.
2) On a temporal scale, the small mammal energy use should show parallel fluxes along the
shrub gradient.

Variables measured: Rodent abundance expressed as Minimum Number Known Alive (MNKA),
rodent biomas, rodent energy, and rodent species richness.

Ecotone rodent trapping

Study number: 

262

Data set ID: 

210262003

Original investigator: 

Brandon Bestelmeyer

Abstract: 

OBJECTIVE: The purpose of the study is to investigate how pulses of precipitation translate into
pulses of plant above ground net primary productivity (NPP) and how the small mammal community
responds to such changes also in relation to shrub gradient across the landscape. Particularly

OBJECTIVE: The purpose of the study is to investigate how pulses of precipitation translate into
pulses of plant above ground net primary productivity (NPP) and how the small mammal community
responds to such changes also in relation to shrub gradient across the landscape. Particularly
we are interested in how the energy flows through the ecosystem in response to pulses of rain,
how the small mammal community partition resources (in terms of C3 (forbs and shrubs) and C4
(grasses) plants) and how the genetic structure of some species (i.e.: Dipodomys spp.) is
affected by their population dynamics.

HYPOTHESES:
1) Small mammal abundance should respond positively to precipitation and NPP.
2) On a temporal scale, the small mammal energy use should show parallel fluxes along the shrub
gradient.
3) The small mammal community should consume C3 and C4 plants according to their availability (or
NPP).
4) At low population density, dispersal should be limited and the genetic variance will be
distributed among populations rather than within (i.e., Fst will trend towards higher values).
After pulses of rain and NPP, population densities will be greater, dispersal prevalent, and
the genetic variance of populations will be distributed within populations (i.e., Fst will
approach zero) as dispersal homogenizes populations.

Variables include rodent species, sex, reproductive status, weight, and maturity status were recorded.

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