This file was created by scanning the printed publication. Errors identified by the software have been corrected; however, some errors may remain. Observations of Arthropod Populations Following the La Mesa Fire of 197']1 Warren F. Pippin2 and Barry Nichols3 Abstract.-Sampling sites were selected in burned and unburned areas where transects for bird surveys had previously been established. Plots were selected randomly in each site and sampled weekly. A 50 m2 plot was selected in a severely burned area and an unburned area nearby and observations made on arthropod populations. There were more genera collected in the unburned than the burned areas. Generally, the most com­ mon arthropods found in burned and unburned areas were ants and spi­ ders. A New Jersey light trap operated at Ponderosa campground in 1977, before the fire, collected several hundred specimens per trap night. In 1978, the volume of specimens collected in the trap was similar to that collected before the fire. In some areas the drastic reduction in arthropod popula­ tions might have had an adverse effect on populations of some insectivo­ rous birds or other animals. INTRODUCTION pine-fir-aspen forest; and Frijoles Canyon, riparian habitat (1/2 mile below Upper Crossing). On June 16, 1977, the La !v1esa Fire started adja­ cent to Bandelier National Monument, New To sample the arthropod populations in the se­ Mexico and subsequently swept through a large lected burned and unburned sites, a metal frame part of the Monument. The progress of the fire and was constructed that was large enough to cover an its ecological aftermath have been extensively area 1/2 X 1 m. The frame was then thrown in a ran­ documented, providing a framework for investi­ dom manner so it fell within the sample site. The gating fire effects upon arthropod populations. area within the frame was then examined for ap­ proximately 15 minutes and all observed A general inventory of arthropods that occur on arthropods collected and placed in collecting vials Bandelier had been initiated in May 1977 as part of containing 70% alcohol. Any flying insects that the VIP program of the NPS. Approximately one landed in the sample area were stunned with a fly month after the fire, it was decided to sample ar­ swatter and collected. The frame was then flipped to thropod populations in burned and unburned ar­ cover another 1/2 m and the process repeated. The eas of the Monument, in an effort to document total area covered for each sample was then 1 sq. changes, if any, in genus composition and to some meter. Five such paired samples were taken from extent numbers. Collections were largely confined each site on a weekly basis from July 18-August 26, to macrofauna of the Class Insecta. 1977. Vials containing the samples were labeled and returned to the laboratory for sorting, counting and shipment to specialists for generic determination. MATERIALS AND METHODS Sampling sites were selected in are~s where per­ 1 Technical editor's note: This paper was presented at the original La manent transects for bird surveys had previously Mesa Fire Symposium in October, 1981, and was inadvertently omitted been established by Roland Wauer. These areas are: from that symposium proceedings. It is included here to make its find­ Frijoles Mesa, pinyon-juniper woodlands; Burnt ings more generally available. Mesa, ponderosa-pinyon-juniper woodlands; 2Medical Entomologist (retired), 227 Whitecliff, San Antonio, TX 78227 Escobas Mesa, ponderosa forest; Apache Mesa, 3Park Technician, 1105 Lauren Lane, Dayton, TX 77535 161 Approximately 10 days after the fire was Table 1.-Arthropod genera collected in burned and unburned brought under control the principal author, while areas of Frijoles Mesa. in a volunteer status, selected two 50 m square Burned (7214)1 Unburned (97/13) plots for observation and collection of arthropod specimens. One plot was in a severely burned area Hymenoptera Hymenoptera of ponderosa pine-scrub oak near Ponderosa Formicidae Formicidae Campground and the other in a similar unburned Camponotus sp. Pheidole sp. Formica sp. Camponotus sp. 1/2 area approximately mile down the fire road Formica sp. toward Frijoles Canyon from Ponderosa Camp­ ground. Specimens were collected with a standard Coleoptera insect collecting net and by physical examination Tenebrionidae Coleoptera of the plots. Collections were made in July 1977 Eleodes sp. Buprestidae Acmaeocora sp. and July 1978. Orthoptera Coccinellidae sp.* It was intended to use a 12 volt battery-operated Acrididae Anatis sp. Melanoplus sp. UV light trap in the transect sampling sites in 1977, Diptera but unfortunately none became available. A 110 Chloropidae volt New Jersey light trap, borrowed from the U.S. Hippelates sp. Air Force, was operated 3 nights per week at Pon­ Muscidae derosa Campground from May 18-June 24, 1977, Fannia sp. prior to the fire and from July I-Sept. 1, 1977, fol­ Orthoptera lowing the fire. Ouring the summer of 1978 a 12 Gryllidae volt battery-operated light was available and was Gryllus sp. used to sample night flying insects in the burned and unburned 50 m2 plots described above. Hemiptera-Heteroptera Miridae Irbisia sp. Psyllidae RESULTS Trioza sp. Tables 1,2,3,4 and 5 show the relative number of Araneida Lycosidae genera collected in each site in the transect areas. Lycosa sp. As might be expected there were more genera col­ Theridiidae lected in the unburned than the burned areas. For Theridion sp. example, Table 1 shows 72 individuals collected Chilopoda from 4 genera in the burned site and 97 individuals Arenophilus sp. belonging to 13 genera in the unburned. (These 1 # of individuals/# of genera. numbers are indicated in parentheses following the * Only identified to family. column headings for the table.) The number of in­ dividuals did not vary significantly. Generally the most common arthropods found in burned and unburned sites were ants and spiders. The only found on grass. In the unburned plot 24 genera specimen collected of special interest was one spi­ were collected in 1977 and 44 genera in 1978. der, Robertus sp. found in a burned area on Escobas A New Jersey light trap operated at Ponderosa Mesa. This is apparently a new record for this ge­ Campground in 1977 before the fire collected sev­ nus in New Mexico and may be a new species. eral hundred specimens per trap night, primarily Table 6 shows the result of collections in the Lepidoptera, Coleoptera and Diptera. Following burned and unburned 50 m2 plots near Ponderosa the fire collections were reduced an estimated 75%. Campground in July 1977 and 1978. In 1977 the Collections never reached pre-fire levels by Sep­ burned area was almost devoid of visual arthropod tember 1977. No records were kept of actual num­ activity. Four genera, consisting primarily of ants, bers, except in the case of mosquitoes. It is interest­ were collected. The only apparent arthropod life ing to note the average number of mosquitoes per was found under fairly large stones and then only trap night was 4 before the fire and 5 after. It was in limited numbers. In 1978, 15 genera were col­ observed that after the fire there was a dramatic lected in the burned plot. The first insect to appear reduction in filth fly populations. The numbers in any abundance was a species of leafhopper remained very low the remainder of the summer. 162 Table 2.-Arthropod genera collected in burned and unburned Table 3.-Arthropod genera collected in burned and unburned areas of Burnt Mesa. areas of Escobas Mesa. Burned (78/5)1 Unburned (91/14) Burned (51n)1 Unburned (72113) Hymenoptera Hymenoptera Hymenoptera Hymenoptera Formicidae Formicidae Formicidae Formicidae Pheidole sp. Myrmica sp. Camponotus sp. Formica sp. Camponotus ap. Pheidole sp. Formica sp. Lasius sp. Lasius sp. Pheidole sp. Araneida Camponotus sp. Diptera Lycosidae Muscidae Diptera Pardosa sp. Hemiptera-Heteroptera Musca sp. Muscidae Cicadel/idae Fannia sp. Diplopoda Gyponata sp. Areneida Abacion sp. Miridae Lycosidae Coleoptera Polymerus sp. Lycosa sp. Carabidae Chilopoda Nabidae Robertus sp. Harpalus sp. Arenophilus sp. Nabis sp. New record from NM, Curculionidae Deptera may be new species. Thricolepis sp. Muscidae Musca sp. Diplopoda Hemiptera Fannia sp. Abacion sp. Cicadellidae Gyponana sp. Orthoptera Chilopoda Miridae Acrididae Arenophilus sp. Psallus sp. Melanoplus sp. Araneida Coleoptera Lycosidae Scaratraeidae Lycosa sp. Polyphaga sp. Pardosa sp. Gnaphosidae Araneida Gnaphosa sp. Lycosidae Thomisidae Lycosa sp. Xysticus sp. Gnaphosidae Gnaphosa sp. Diplopoda Abacion sp. Diplopoda Abacion sp. 1 # of individuals/# of genera. 1 # of individuals/# of genera. unburned areas. The number of individual speci­ mens collected did not vary significantly. This may In 1978 the volume of specimens collected per be due to easier visibility for collecting in burned trap night was similar to that collected before the areas. Most of the individual specimens collected fire in 1977. The UV light trap that was operated in the burned areas were ants and spiders. In se­ two nights in July at the burned and unburned verely burned areas, such as the 50 m2 plot near plots produced similar catches at each plot, consist­ Ponderosa Campground, virtually all arthropods ing primarily of Lepidoptera in the families were eliminated. One year after the fire the number Arctiidae, Lasiocampidae, N octuidae, Sphingidae, of genera collected increased, but were below the Geometridae, Zygaenidae, Pyralidae, Gelechioidea, number of genera collected in the unburned area in Notodontidae, and Saturniidae. 1977. The unburned 50 m2 plot was near burned areas and was undoubtedly subjected to heat and smoke. This may account for the small number of SUMMARY AND CONCLUSIONS fly genera collected in 1977 (3) as opposed to the larger number collected in 1978 (10). Strong fliers Arthropod collections were made in selected may have an opportunity to leave the area or per­ sites at Bandelier National Monument, NM, follow­ haps most were eliminated by heat and smoke.