This data set contains records for the numbers of selected groups of ground-dwelling arthropod species and individuals collected from pitfall traps at 4 sites on the Sevilleta NWR, including creotostebush shrubland, both black and blue grama grasslands, and a pinyon/juniper woodland. Data collections begin in May of 1989, and are represented by subsequent sample collections every 2 months. One site (Goat Draw/Cerro Montosa) was discontinued in 2001, and a new site (Blue Grama) was initiated . Only three sites, creosotebush, black grama, and blue grama were continued between 2001-2004.
To monitor the species composition and relative abundance's of select ground dwelling arthropod taxa and trophic groups from principal long-term study sites/environments in relation to climate change and plant production.
Arthropods have been collected from four subjectively chosen sites on the Sevilleta National Wildlife Refuge (SNWR), representing the following habitat types: pinyon-juniper (elev. 2195 m), black grama grassland, blue grama grassland, and creosotebush shrubland (elev. ~1400 m for all three). At each of the four sites there were 30 traps arranged in five replicate lines with six traps per line. Each line was located outside a mammal trapping web, except at Goat Draw, where mammal trapping webs were installed three years after the arthropod traps. In 1995 Robert Parmenter and Sandra Brantley decided to reduce the number of traps by half. Comparative statistical tests run with data from 15 traps showed no difference in mean abundances of dominant species compared to tests with 30 traps. The interannual variability is high and it is hoped that the long-term aspect of the monitoring will produce clearer patterns than intensive sampling over a short period has done. Traps 1, 3 and 5 were left and traps 2, 4 and 6 were removed. The decision was also made to process samples from only the odd-numbered traps beginning with the 1993 samples. The experimental design was intended to provide data for long-term monitoring of ground arthropods in relation to climate and plant production. The traps within each trap line are subsamples, and data from those should be summed or averaged for a single value per line, per sample period. The lines are intended to serve as replicate samples for each habitat site, however, they were not randomly located. The lines were located to provide a systematic array with trap lines approximately 200 meters from each other on the landscape.
During a collection period the contents of each trap are strained out of the glycol so that it can be reused. Glycol is replenished as needed to keep the cups about half full. Arthropods are transferred from the strainers to glass vials containing site labels. The contents of each trap are stored in a separate vial. Trap condition forms are filled out at the time of collection and kept with the samples. Any traps that are damaged or not functioning are re-set.
Arthropods are collected in pitfall traps, made of a 15 oz. can (11 cm tall and 7.5 cm in diameter) dug into the ground so that the opening of the can is flush with the ground. A screen apron was fitted around the top of the can to prevent rodent digging. Plastic 10 oz. cups about half-full of propylene glycol (ethylene glycol prior to March 1994) are inserted in the can. The glycol is a preservative; no live pitfall trapping of arthropods is done. The traps are covered by raised ceramic lids, 15 cm x 15 cm in size. The traps remain open all year, and samples are collected everly two months during the week of the 15th day of each months, for the months: February, April, Jun, August, October, and December.During a collection period the contents of each trap are strained out of the glycol so that it can be reused, using standard hand-held metal screen kitchen strainers approximately 3 inches diameter. Glycol is replenished as needed to keep the cups about half full. Arthropods are transferred from the strainers to glass vials containing site labels. The contents of each trap are stored in a separate vial. Trap condition forms are filled out at the time of collection and kept with the samples.
Specimens are stored in 70 % ethanol. Specimens are brought back to the UNM Museum of Southwestern Biology (MSB) wet lab for processing. Sample sorting, arthropod identification, and data tabulation are performed only by individuals trained as entomologists, or entomologically experienced graduate students trained in arthropod identification specifically for this project. Individual arthropods are identified to morphospecies and counted. Classifications generally follow Nomina Insecta Nearctica: a checklist of the insects of North America, Volumes 1-4, however, taxonomic levels above family follow Borror, DeLong and Triplehorn's An Introduction to Entomology, 5th edition. Higher classification for Orthopteroids follow Arnett, 2000 (per DLC). And classification of Aranae follows Roth's Spider Genera of North America, 2nd and 3rd editions. The species code, number of individuals, site name and date of collection are entered on a data sheet. After processing, all the samples from one site and date are pooled for long-term storage in sealed jars containing 70% ethanol, at the UNM Biology Field Station, located at the Sevilleta NWR. Detailed procedures for sorting and identifying the arthropods are available from the Sevilleta data manager (firstname.lastname@example.org). Reference collections are maintained at the Sevilleta Field Station and at the UNM Museum of Southwestern Biology Division of Arthropods. Voucher specimens are housed in the UNM MSB Division of Arthropods.
Ground arthropod species in the following taxonomic groups are collected, counted and identified to morphospecies:-orthopterans, including grasshoppers, field crickets and camel crickets-blattarians, sand cockroaches-mantodeans, only ground mantids-phasmatodeans, walkingsticks-hemipterans, selected taxa only: lygaeids, alydids, one genus of mirid, thyreocorids, cydnids-coleopterans-microcoryphians, bristletails-chilopods-diplopods -isopods-arachnids, including spiders, scorpions, solpugids, uropygids, opiliones.
Specimens are pinned or placed in 70 % ETOH, labeled, and added to the LTER collection or to the UNM Division of Arthropods collection as needed. If the specimens are not needed they are kept in alcohol storage and housed at the Sevilleta Field Station. See: /sevilleta/export/db/work/insect/specieslists/sevrefcoll for a list of specimens vouchered by the MSB. The focus of the pitfall collections is on the adult stage, but nymphs of orthopteroids and hemipterans and immature stages of arachnids are identified to genus or species if possible. If not, these groups have species i.d. numbers for nymphal or immature stages. Larval beetles are not counted. The aleocharine staphylinid species are grouped together under species number Co Sta 001 088.
January 2009Combined all data from 1992-2004. QA/QC'd data from 2001-2004 in excel using a filter and checking data line by line. All data were then imported into Navicat using the import wizard.
Data from 1989-1991 were removed and stored elsewhere. Contact data manager for data. --A.Swann
Field collections are made every even-numberedmonth as close to the 15th as possible.
This study/data set is a subset of the original larger scale Sevilleta LTER data set #: SEV0029; "Arthropod Populations". The number of arthropod taxa included in this data set ("Sevilleta Ground Arthropods") has been reduced to those taxa that are appropriately sampled by pitfall traps, and those taxa or taxonmic ranks that can be easily identified and tabulated by expert technical staff. The number of study sites also was reduced from seven to four for this data set. Associated data sets include climate data from representative Sevilleta LTER meterological stations, and plant production data from Sevilleta LTER above ground net primary production plots, located on or near the arthropod pitfall trap sites.