primary productivity

Dataset: 

Study number: 

262

Data set ID: 

210262005

Date range: 

2005-01-01 to 2014-12-31

Original investigator: 

Brandon Bestelmeyer

Data contact: 

Abstract: 

   Dataset consists of the annual aboveground net primary production (ANPP) across 3
   habitats grouped by plant form and total ANPP.  The habitats are grassland, mesquite
   shrubland, and the ecotone between the 2. The plant forms are winter annual forb,
   annual forb, bi-annual forb, perennial forb, annual grass, perennial grass, shrub, and
   sub-shrub.

   Dataset consists of the annual aboveground net primary production (ANPP) across 3
   habitats grouped by plant form and total ANPP.  The habitats are grassland, mesquite
   shrubland, and the ecotone between the 2. The plant forms are winter annual forb,
   annual forb, bi-annual forb, perennial forb, annual grass, perennial grass, shrub, and
   sub-shrub.

   OBJECTIVE:  The purpose of the study is to investigate how pulses of precipitation
   translate into pulses of plant aboveground 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 (e.g., 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.

   Total aboveground annual net primary productivty is calculated for winter annual forb,
   annual forb, bi-annual forb, perennial forb, annual grass, perennial grass, shrub,
   sub-shrub, and the total of these.
 

Data download: 

Description: 

Data file (CSV) for the Jornada dataset: Ecotone Study: Plant Above Ground Net Primary Productivity by Site

Data file (CSV) for the Jornada dataset: Ecotone Study: Plant Above Ground Net Primary Productivity by Site

LTER Core Area(s): 

Keywords: 

Dataset: 

Study number: 

11

Data set ID: 

210011003

Date range: 

1990-01-01 to 2015-12-31

Original investigator: 

Laura Huenneke

Data contact: 

Abstract: 

Summarizes mean aboveground net primary production, in g/m2/yr, by year for each of 15 sites. Annual totals derived by summing seasonal production values for winter (October - February), spring (February - May), and fall (May - October) increments for a single calendar year.

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).

Data download: 

Description: 

LTER Core Area(s): 

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): 

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