Jornada Basin LTER Research

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Dataset: Transect Mesquite Litterfall


   Download data: File mesqlitr.dat
   File description including attribute definitions: data_JornadaStudy_389_transect_mesquite_litterfall
   Original Investigator: Walter G Whitford
   Data contact: John Anderson
   Duration: 1985 - 1988
   Dataset ID: 210389002
   Abstract:

Mesquite litterfall collected monthly from mesquite fringe on south side of College Playa. Oven-dry weights of leave, stem, and seed fractions as well as total dry weight are recorded.


   Additional information:

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. The northeast side of the exclosure is immediately upslope of the College Playa located near the NMSU College Ranch. Three parallel transects (2.7 km in length) run from the middle of the College Playa up into the foot of Mt. Summerford. The Control transect is to the west, the Treatment transect on the east side of the Control transect, and the Alternate Control to the east of the Treatment transect. Each transect is 30 meters wide with a 45 meter buffer zone between each transect. The Treatment transect was treated annually until 1987 with NHNO3 in a concentration equal to 10g N/m2. The station markers at 30 meter intervals along each transect. Perpendicular to each transect and crossing at each station marker is the 30 meter plant line intercept transect. This extends 15 meters on either side of the station marker. The ends of the plant line intercept transect are marker by short rebar sticking up about 6 inches aboveground. The plant line intercept transects are thus perpendicular to the direction of major drainage flow. The litterfall traps are in the mesquite fringe by the College Playa. LTER-I Control transect, between Station C7 and C10 LTER-I Treatment transect, between Station T7 and T9

   Methods:

field data book

   Methods:

Litter is collected monthly using a CarVac vacuum run off of a rechargeable 12 volt battery. There are 10 mesquite shrubs from which mesquite litter is collected. Litter is caught under each mesquite with 4 30 cm2 aluminum screen baskets located midway under the canopy with a basket at each of the cardinal directions. Baskets are elevated on 3/8" rebar situated under mesquite shrubs on each transect. Litter is dried at 55 degrees Celcius for 72 hours. Dry weight of total mesquite litterfall per basket is recorded. The sample is sorted into leaf, stem, and seed fractions, and the dry weight of each is recorded as described below. For the period 07/11/1985 through 11/01/1985 the litter from all 10 shrubs was combined, mixed thoroughly, and approximately 10 grams subsampled which was sorted for leaf, stem, and seed fractions. Beginning in 12/03/1985 a 5 gram subsample from each shrub was sorted into leaf, stem, and seed fractions. During late winter, spring, and early summer there was no mesquite litter to collect and these periods are not represented in the data set for mesquite litterfall.

   Maintenance:

monthly