Methods:
Arthropod pitfalls were established in January of 1995 at the
start of LTER III; this design is significantly different from the
pitfalls of LTER II, when lizards and arthropods were collected in
the same traps. The newer arthropod pitfalls consisted of a small
tin can (buried flush with the soil surface) in which a plastic
cup (10 oz.) fits snugly. The cup was filled (about 3/4 full) with
propylene glycol (the "non-toxic" antifreeze, Sierra
brand) which captures and preserves any arthropods that stumble
in. A ceramic tile shaded the trap, supported by 4 nails sticking
about 1" above the ground.
To minimize rodent damage to the pitfalls, chicken wire fences
with lids were installed around each trap. Unfortunately, rodents
or lizards smaller than the holes in the chicken wire continued to
cause significant damage to the traps after the exclosures were
added, so in June 1996, hardware cloth collars were also added to
the pitfalls. These collars were squares about 10" on a side
with a hole cut in the center for the can and cup combination.
Additional holes were cut for any grass clumps surrounding the
pitfalls to minimize disturbance to the vegetation. They were
buried under a thin layer of soil. Because of concern about the
numbers of vertebrates (small rodents and lizards) being caught in
the pitfalls, in February 1996, 1/4" hardware cloth ladders
(5 " long x 3/4 " wide) were added to the traps. It was
hoped that rodents and lizards would be able to escape, while
arthropods would not (due to the strength of the surface tension
of propylene glycol).
The traps were continuously open, and the arthropods in them
collected, identified, and counted every 2 months. If there were
no arthopods in the trap (count=0) then all taxonomic columns in
the data file are filled with 'XX'.
If time permitted, during the month in between collections, the
traps were checked once, to top off the propylene glycol, and
repair any wind/rain/rodent/coyote/vandal damage. During windy
seasons, the traps at M-RABB and M-NORT sometimes needed to be
collected monthly because of large volumes of sand collecting in
the cups. This occurred if cups became close to 1/2 full of sand
in one month’s time.
There are five arthropod pitfalls at each of the NPP study sites,
excluding the playas. The five traps are in a line, 15m from each
other, marked with orange pin flags. The following list tells
where the line of traps for each site was, relative to the NPP
grid: C-GRAV=NW corner, C- SAND=south side, C-CALI=SW corner,
G-SUMM=NE corner, G- BASN=east side, G-IBPE=NW corner, M-WELL=east
side, M- RABB=west side, M-NORT=south side, T-TAYL=east side, T-
EAST=east side, T-WEST=south side. In addition, from January 1995
to March 1997, at G-IBPE and C-SAND, there were 12 extra pitfalls,
used in a cross-site study for comparison to data from the
Sevilleta and Bandelier. These extra pitfalls were in 4 sets of 3,
distributed on all sides of the NPP grid (see maps). Each trap was
numbered for identification, and these numbers were written on the
underside of the tile over each trap.
Additional files
'jorn-arthpit-taxa-lst.txt' is a text file describing the
taxonomic codes used in the data file (order, family, genus, and
species columns). The 'Taxon Code' column should match (at least
some of) the taxonomic codes in the data file.
'arthpit3.dsd' is a metadata file created during the time of the
study. It contains additional metadata that may not have been
placed into the current EML file for this data package.
Related publications
Lightfoot, D. C., Brantley, S. L., & Allen, C. D. (2008).
Geographic patterns of ground-dwelling arthropods across an
ecoregional transition in the North American Southwest. Western
North American Naturalist, 68(1), 83-102.
