Collections of airborne sand are obtained at the 15 NPP sites and the Geomet site. The collections are taken using BSNE collectors. The collectors are turned into the wind with wind vanes. The amount of material collected corresponds to the horizontal flux at the height of the collector and the opening area of the collector and the duration of the sampling time. The five heights of the BSNE collectors above the soil surface are 5, 10, 20, 50, and 100 centimeters for every location where samples are taken. The hypothesis of the experiment is that the vertical flux of the particles smaller than 10 micrometers is a constant ratio of the horizontal sand flux. The objectives of the experiment are to find patterns of sand flux rates as affected by soil and vegetation.
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
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
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.
Dataset consists of plant measurements used to calculate 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.
Repeat digital groundbased photos are taken once to twice a year to document plant litter and
soil deposition or removal by wind and water transport on ten microplots located on each of the
8 plots at each of the Aeolian, Dona Ana, and Gravelly Ridges sites. Five photos are taken of
each microplot: One overhead (from directly over the microplot) and 4 lateral views at ground
level of the microplot from each cardinal direction.
Digital filenames are fully descriptive of the site, plot, microplot, photo view, and date taken.
Photo filename structure:
Where 1 = site: A=Aeolian: D=Dona Ana; G=Gravelly Ridges
2 = plot (1-8)
3 = microplot (1-10)
4= photo view (O=overview; E=looking east; N=looking north; S=looking south; W=looking west
5-6-7 = year month day of photo
8 = original image number assigned by camera
There are 3 sites for this study: Gravelly Ridges, Aeolian, and Dona Ana. Within each site,
there are 8 plots. The plots are 8x8 meters and have an 8x8 buffer zone on both sides of the
plot (up and down). There are four BSNE stands for each plot, 2 in each of the 2 buffer zones
(8 collectors per plot). Each stand contains 2 BSNE collectors with the collection opening at
10cm and 30cm height and an opening of 2 cm wide and 5 cm height. These BSNE collectors are in
a fixed position pointing into the direction of the prevailing wind, which corresponds to the
plot alignment. The collectors in the upwind buffer are facing away from the plot and the
collectors in the downwind buffer are facing into the plot. The idea is the upwind BSNEs
measure the amount of dust entering the plot, and the downwind BSNEs measure the amount of dust
moving off the plot. This provides a measure of the effectiveness of the plot obstructions to
wind blown dust. It is important the BSNEs are fixed in an orientation that points across the
full length of the plot.
Monthly soil water content measurements are made at 10 depths (where
possible) at each of 10 access tubes at each of the 15 LTER-II NPP
sites using a neutron probe (CPN Model 503DR Hydroprobe). The counts
of thermalized neutrons are adjusted for the decay rate of Americium
241, then converted to soil water content using individual site
regressions. Soil water content is a volume/volume relationship and
represent cm3 water/cm3 soil. Data are provided at 30cm intervals from
30cm to a maximum of 270cm soil depth, shallower when an impenetrable
caliche layer is reached. Field readings may include one at 300cm;
however, the value for the deepest depth of each access tube is removed
from the calculated soil water content data because of the effect of
measuring greater soil volume directly below the probe than that of the
more shallow depths.
This data set is comprised of daily precipitation totals, in inches, measured by Belfort
Instruments weighing rain gauges at 58 locations on the Jornada Experimental Range.
Locations and the dates during which data were collected at them were generally project-oriented.
See comment section (#20) for start and end dates for each location.
Days on which data could not be obtained (due to equipment failure, user error, and/or
other reasons) are flagged as missing within this dataset. As of 31 December 2008 they
comprised 1,270 of the total 291,465 records, which is less than 0.44% of the data set.
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: