+------------------------------------------------------------------+
|                             JORNADA LTER                         |
|                      New Mexico State University                 |
|                   Research Project Description Form              |
+------------------------------------------------------------------+
All Jornada Desert Site NSF / LTER projects must be documented on
the following form.  In addition, associated data sets must also
be described on Data Set Documentation Forms, available from the
data manager. Information that is not available at this time,
must be included when available. For these fields, enter
<NOT AVAILABLE>.  For fields that will not have information, enter
<NONE>. See data manager for any questions regarding this form.
--------------------------------------------------------------------

 1) Project title:
    --------------
    Effects of harvester ant nests on soil properties and vegetation

 2) Responsible investigator:
    -------------------------
    Rodolfo R. Di Marco

 3) Date research commenced (mm/dd/yyyy):
    -------------------------------------
    January 1987

 4) Date research terminated (mm/dd/yyyy):
    --------------------------------------
    June 1987

 5) PI funding the research:
    ------------------------
    W. G. Whitford

 6) Additional investigator(s):
    ---------------------------
    <NONE>

 7) Funding agency (ex. NSF, USDA):
    -------------------------------
    NSF

 8) Funding cycle (Ex. LTER II, N/A):
    ---------------------------------
    LTER I


 9) Informative abstract (Describe research project completely.
    Include project OBJECTIVES/HYPOTHESIS.)
    ----------------------------------------------------------------
       Cover and density of winter annual plants on the perimeters of
    ant nests were compared with those of adjacent reference sites in
    three habitats at Jornada LTER, New Mexico, USA.  There was a
    distinct floristic assemblage of winter annual plants on ant nest
    perimeter in comparison to reference sites.  Descurainia pinnata,
    Lesquerella gordonii, Malacothrix fendleri and Eriogonum
    abertianum were strongly associated with ant nest perimeters and
    had higher cover on ant nest perimeters.  The floristic
    assemblages and cover were least affected by presence of
    harvester ant nests in the grama grassland habitat and most
    affected in the basin slope mixed habitat.  Soil chemical
    analyses did not show large generalized differences in nutrient
    contents.  However, there were higher concentrations of NO3-N and
    inorganic P on ant nest perimeters and also, there were different
    ratios of resources (e.g., water and N and P availability) due to
    ant soil disturbance on ant nest perimeter.  Floristic assemblage
    could be determined by a fortuitous juxtaposition of clumped
    seeds at beginning of winter, by intra and interspecific
    competition of winter annual during February and March, and
    mediated by ant clipping at the end of April and May.  There were
    no significant differences in below ground biomass between ant
    nest perimeter and reference sites.  This many be due to intense
    clipping of annual plants by ants on nest perimeters in April.

10) Data set(s) associated with project:
    ----------------------------------------------------------------
                                                       Documentation
    Data set title                                     file name
    -------------------------------------------------  -------------
    Density and cover of winter annual plants          ANDENCOV.DSD
    Ant nest soil nutrients                            ANSNUTR.DSD
    Ant nest soil organic matter                       ANSORGAN.DSD
    Ant nest soil water content                        ANSWC.DSD

11) Publications resulting from project research:
    ----------------------------------------------------------------
    Di Marco, Rudolfo Ruben. 1987. "Effects of harvest ants,
       Pogonomyrmex rugosis, nest on soil properties and vegetation
       in the Chihuahuan Desert." M.S. Thesis, New Mexico State
       University.
    Whitford, Walter G., and DiMarco Rudolfo. 1995. Variability in
       soils and vegetation associated with harvester ant
       (Pogonomyrmex rugosus) nests on a Chihuahuan Desert watershed.
       Biology and Fertility of Soils 20: 169-73.

12) Comments (Include any comments that here that more full describe
              this project):
    ----------------------------------------------------------------
    No documentation was completed by the investigator.  Project and
    data set documentation was completed by the LTER Data Manager
    with information obtained from Di Marco (1987) and header infor-
    mation from SAS files which also contained the data.

13) Project file history log:
    ----------------------------------------------------------------
    Project title     - Effects of harvester ant nests on soil
                        properties and vegetation
    Project file name - ANTNESTS.PRJ
    -------------------------------------------------------------
         mm/dd/yyyy      - Date of comment (month/day/year)
         Int             - Initials of person making comment
                           JPA = John P. Anderson
                           MAB = Michelle A. Buonopane
         Changes/Updates - List any changes made to document

    mm/dd/yyyy  Int  Changes/Updates
    ----------  ---  -----------------------------------------------
    02/04/1998  JPA  Project documentation completed.
    06/04/2002  MAB  Associated data sets updated.
    ----------------------------------------------------------------
                           END OF PROJECT FILE
    ----------------------------------------------------------------