This data package contains reference harvest measurements for the
long-term Net Primary Production (NPP) study at the Jornada Basin
LTER. Data here include horizontal cover, vertical height, and
aboveground biomass of plants harvested near, but outside, a grid of
permanent NPP quadrats at each of 15 NPP sites. These sites were
selected to represent the 5 major ecosystem types in the Chihuahuan
Desert (upland grasslands, playa grasslands, mesquite-dominated
shrublands, creosotebush-dominated shrublands, tarbush-dominated
shrublands). For each ecosystem type, three sites were selected to
represent the range in variability in production and plant
diversity; thus the locations are not replicates. All sites are
excluded from domestic grazing. Eleven sites are in non-grazed
pastures, and at the other four sites 1 hectare areas around the
observational plots were fenced in 1988. At all sites a grid of 49
(48 at one playa location) 1m x 1m replicate quadrats was laid out
when sampling began in 1989. Harvests are made outside the quadrat
grid, but inside the fence. Height and cover are recorded in the
field. Live biomass is weighed in the lab and all measurements are
recorded as reference harvest data. Subsequently, regressions
between the harvested biomass and plant volume values are used to
derive allometric equations that determine biomass from
non-destructive volume measurements in the permanent NPP quadrats.
Further details are described in the methods metadata. This is an
ongoing study with new harvest data (from selected species)
collected in the spring, fall, and winter each year.
Attention:
These data are not appropriate for
estimates of percentage cover because of the way the data are
collected.
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Seasonal non-destructive vegetation measurements at 15 net primary production (NPP) study sites at Jornada Basin LTER, 1989-ongoing
This data package contains non-destructive quadrat measurements
collected for the long-term Net Primary Production (NPP) study at
the Jornada Basin LTER. Data here include measurements of horizontal
cover and vertical height of plants observed at permanent NPP
quadrats at 15 study sites. Sites were selected to represent the 5
major ecosystem types in the Chihuahuan Desert (upland grasslands,
playa grasslands, mesquite-dominated shrublands,
creosotebush-dominated shrublands, tarbush-dominated shrublands).
For each ecosystem type, three sites were selected to represent the
range in variability in production and plant diversity; thus the
locations are not replicates. All sites are excluded from domestic
grazing. Eleven sites are in non-grazed pastures, and at the other
four sites 1 hectare areas around the observational plots were
fenced in 1988. At all sites a grid of 49 (48 at one playa location)
1m x 1m replicate quadrats was laid out when sampling began in 1989.
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). Standing vegetation in quadrats is sampled three times a
year: in winter (February - March), before shrubs begin spring
growth; in spring (May), when shrubs and spring annuals have reached
peak biomass; in fall (late summer; October), when summer annuals
have reached peak biomass but before killing frosts. Additional
observations of plant count and phenological stage are also made.
This dataset is subsequently used to determine quadrat biomass and
net primary production. Details and linked data packages are
described in the methods element. This is an ongoing dataset with
new quadrat measurements collected in the spring, fall and winter of
each year.
Attention:
1) For most species, these data are
not appropriate for estimates of percentage cover because of the way
the data are collected.
See Note 1 in the methods element
for further details.
more »
« less
- Award ID(s):
- 2025166
- PAR ID:
- 10476988
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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This data package contains reference harvest measurements for the long-term Net Primary Production (NPP) study at the Jornada Basin LTER. Data here include horizontal cover, vertical height, and aboveground biomass of plants harvested near, but outside, a grid of permanent NPP quadrats at each of 15 NPP sites. These sites were selected to represent the 5 major ecosystem types in the Chihuahuan Desert (upland grasslands, playa grasslands, mesquite-dominated shrublands, creosotebush-dominated shrublands, tarbush-dominated shrublands). For each ecosystem type, three sites were selected to represent the range in variability in production and plant diversity; thus the locations are not replicates. At each site, a 1 hectare area was fenced in 1988 and a grid of 49 (48 at one playa location) 1m x 1m replicate quadrats was laid out when sampling began in 1989. Harvests are made outside the quadrat grid, but inside the fence. Height and cover are recorded in the field. Live biomass is weighed in the lab and all measurements are recorded as reference harvest data. Subsequently, regressions between the harvested biomass and plant volume values are used to derive allometric equations that determine biomass from non-destructive volume measurements in the permanent NPP quadrats. Further details are described in the methods metadata. This is an ongoing study with new harvest data (from selected species) collected in the spring, fall, and winter each year. Attention: These data are not appropriate for estimates of percentage cover because of the way the data are collected.more » « less
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