plant species

Dataset: 

Study number: 

39

Data set ID: 

210392001

Date range: 

1939-01-01 to 2001-12-31

Original investigator: 

Ken A Valentine

Abstract: 

The purpose of this study is to quantify vegetation dynamics in response to lagomorph and shrub exclusion. Data consist of vertical line intercept measures of the perennial grasses, suffretescents and shrubs. Sixteen plots at each of 3 sites (Gravelly Ridges, Dona Ana exclosure, and Parker Tank) were established in 1938-39 by Ken Valentine.

Plots were 21.3 x 21.3 m in 4 rows of 4 plots with a 7.6 m buffer zone. All plots were sampled before treatments. Plots were divided into east and west halves and 14 randomly located 10.65 m transects were located in each half plot. Vegetation (black grama, dropseeds, bush muhly, fluff grass, other grasses, creosotebush, honey mesquite, tarbush, mariola, and other shrubs) was measured using vertical line point intercepts. Plots have been re-read in 1947, 1956, 1960, 1967, 1989, 1995, and 2001 for Gravelly Ridges and 1939, 1947, 1960, 1967, and 2001 for Dona Ana and Parker Tank using the same methods. Treatments were applied factorially yielding a control plot, single factor plots, and plots with varying degrees of combinations of factors. The factors were lagomorph exclusion (using wire fencing), shrub removal (hand grubbing at the ground surface), furrowing (shallow, hand raked furrows to trap surface water), and seeding (broadcast applications of seeds of native perennials). Seeding and furrowing treatments were only applied in 1939. Lagomorph exclusion has persisted since establishment, and shrub removal treatments have been reapplied immediately following all years of vegetation sampling. This study is complete.

For more information, refer to:

Havstad, K.M., R.P. Gibbens, C.A. Knorr, and L.W. Murray. 1999. Long-term influences of shrub removal and lagomorph exclusion on Chihuhuan Desert vegetation dynamics. Journal of Arid Environments 42: 155-166.

 

Data download: 

Description: 

<p>Data file information for the following Jornada data set: Line intercept data of long-term vegetation responses to shrub removal and lagomorph exclusion in a creosotebush community</p&g

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LTER Core Area(s): 

Dataset: 

Study number: 

11

Data set ID: 

210011004

Date range: 

1989-04-25 to 2017-09-21

Original investigator: 

Laura Huenneke

Data contact: 

Abstract: 

This is the reference harvest biomass data of plants near, but outside the grid of permanent NPP quadrats that was harvested for each of 15 sites. Height and cover are recorded in the field. Live biomass is weighed in the lab and all measurements are recorded as reference harvest data.

The NPP sites are grids of permanent 1 square meter quadrats established in 15 sites: three sites in each of 5 community zones (grama grassland, creosotebush scrub, tarbush flats, mesquite dunes and playa). Grids consist of 49 quadrats arranged in a square 7 x 7 pattern, with quadrats 10 m apart (P-COLL has 48 quadrats in a 3 x 16 pattern).

Data download: 

Description: 

Data file information for Jornada data set: NPP Study: Reference harvest data file

LTER Core Area(s): 

Keywords: 

Dataset: 

Study number: 

11

Data set ID: 

210011001

Date range: 

1989-05-09 to 2015-12-31

Original investigator: 

Laura Huenneke

Data contact: 

Abstract: 

These data sets contain calculated aboveground biomass values, by species, for each quadrat in each site for a given season. They are constructed (as outlined below) from the field data which are measurements of the physical dimensions (horizontal cover, vertical height) of plants or plant parts in the quadrats.

Objective is to monitor patterns (both temporal and spatial) of aboveground biomass across a range of ecosystem types; to allow the estimation of net primary production and its variability in those ecosystems; and to provide a quantitative description of plant community structure over time in those ecosystems.

Please refer to these publications to evaluate the appropriateness of these data for your intended use prior to contacting Debra Peters, Responsible Investigator, with a data request.

    Attention: These data are not appropriate for estimates of percentage 
    cover. NPP-associated percent cover measurements were developed for 
    and are used solely to provide the best estimate of biomass production. 
    Becuase the methodology results in measurements of overlapping subcanopy 
    systems and canopies of adjacent individuals, NPP percent cover 
    measurements are not an appropriate measure of actual aerial plant cover. 
    Doing so will result in inflated numbers for the "actual" vegetative cover. 
 
    Attention: Data through 2003 was replaced online per below on 9/22/2011. 
    Analyses and results for ANPP differ from previous uses of the data from 
    1989-1998 (Huenneke et al., 2002) in three ways: 
      (1) Yucca elata was removed prior to analysis because its growth form 
          results in large errors in biomass estimates from year-to-year, 
      (2) regressions between biomass and plant volume used an intercept equal 
          to 0 to be consistent with a recent study in a similar system 
          (Muldavin et al., 2008), and 
      (3) reference harvests obtained in extreme years resulted in adjusted 
          regression coefficents through time that reflect year-to-year variation 
          in ANPP. These changes result in ANPP values that are smaller compared 
          (Peters et al. submitted) with previous studies (Huenneke et al., 2002).

LTER Core Area(s): 

Dataset: 

Study number: 

86

Data set ID: 

210086002

Date range: 

1995-04-10 to 2015-10-29

Original investigator: 

David Lightfoot

Data contact: 

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 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 as Brown and Heske (1990a) and Gibbens et al. (1993) suggest? 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?

Data download: 

Description: 

Data file information for the following Jornada data set: SMES vegetation quadrat data

LTER Core Area(s): 

Dataset: 

Study number: 

86

Data set ID: 

210086001

Date range: 

1995-11-08 to 2005-11-17

Original investigator: 

David Lightfoot

Data contact: 

Abstract: 

This is data for perennial plant vegetation canopy cover measured from all SMES study plots, fall 1995. The purpose of this data is to provide ground-truth data for comparison with low-level aerial photographs of each study plot. Three, 29 meter lines were measured along three of six rows of the permanent vegetation measurement quadrats.

Each line was measured at 10cm resolution for intercepts of perennial plant live canopy cover, and for bare ground. 10cm resolution is comparable to the resolution of the aerial photos. All plants were identified to the species level. These line-intercept measurements are taken once every ten years, at the same time that low-level aerial photographs are taken. These data will be compared to both decadal air photos, and annual measures of vegetation from one-meter2 quadrats on each plot to provide information on vegetation change over time relative to the various animal exclosure treatments.

Description: 

Data file information for the following Jornada data set: SMES vegetation line intercept data

LTER Core Area(s): 

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