Lisa K. Harris

A model for assessing wildlife habitats in urban landscapes of eastern Pima County, Arizona (USA)

The loss of large natural areas due to development has increased interest for and use of vegetated areas in urban and suburban areas for wildlife habitats. The goal of this study was to quantify vegetation characteristics for each type of land cover found in the greater Tucson, Arizona area, thereby providing a predictive tool for wildlife management and other land management issues. This research was based on and is a continuation of a pilot study that developed a method associating land cover categories to aerial photographs in eastern Pima County, including the City of Tucson. Aggregation of land cover categories used by Tucson and Pima County and verifications of any uncertain classifications of land cover with field evaluations produced a consistent land cover classification system and database. Natural open space was the largest land cover category within our study area, comprising 52% of the total land cover. Riparian areas, low-density housing and natural open space areas had the highest percentage of native vegetation and escape cover. Golf and neighborhood parks ranked much lower than these land covers relative to native vegetation and escape cover (vegetation with foliage/stems at ground level). The most structurally diverse plant communities were associated with medium density residential areas and zoos that contain a relatively high number of exotic species. Results from the wildlife habitats index indicated riparian areas as the most valuable habitats in eastern Pima County (the county where Tucson is located), followed by low-density housing (≤1 residence/acre), natural open space, and federal/state parks and forests.

Effects of military operations on behavior and hearing of endangered Sonoran Pronghorn

: Our objectives in this study were to determine whether military activities (e.g., overflight noise, noise from ordnance delivery, ground-based human activity) on the Barry M. Goldwater Range (BMGR) affect the behavior and hearing of Sonoran pronghorn (Antilocapra americana sonoriensis). We contrasted the behavior of pronghorn on BMGR with the closest population of pronghorn in the United States that was not subjected to routine military activity (i.e., on the Buenos Aires National Wildlife Refuge [BANWR], Arizona). Forty percent of the landscape used by the endangered Sonoran pronghorn in the United States is within the 5,739 km2 BMGR, a bombing and gunnery facility in southwestern Arizona. The range of Sonoran pronghorn covers about 88% of BMGR. The 179 Sonoran pronghorn that lived in the United States in December 1992 declined to 99 by December 2000. The Sonoran pronghorn has been listed as endangered for >30 years, but population limiting factors are unknown. Because Sonoran pronghorn use BMGR, land and wildlife managers raised concerns about the potential effects of military activities on the population. Possible indirect effects of military activities on Sonoran pronghorn, aside from direct mortality or injury, from ordnance delivery, chaff, flares, live ammunition, aircraft mishaps, interference from ground vehicles and personnel, include alteration of behavior or physiology. We conducted the study on the North and South Tactical Ranges (NTAC and STAC), BMGR, from February 1998 to June 2000. Hearing exams were conducted in Camp Verde, Arizona, the University of Arizona, and on the East Tactical Range (ETAC), BMGR. Interactions between pronghorn and military activity were restricted to 4 observation points that provided viewing areas from which pronghorn and military activity could be observed from ≤ 10 km. We systematically located pronghorn with spotting scopes and telemetry. When located, we described their behavior and military activity using scan sampling. We tested hearing using auditory brainstem responses (ABR). We could not test the hearing of Sonoran pronghorn because of their endangered status, so we contrasted hearing of pronghorn near Camp Verde, Arizona, and desert mule deer (Odocoileus hemionus eremicus) that were and were not exposed to sound pressure levels from military activity. We recorded behavior observations of Sonoran pronghorn on 172 days (44,375 observation events [i.e., 1 observation/30 second]) over 373 hours. These data were compared with 93 days of behavioral data (24,297 observation events) over 202 hours for pronghorn not regularly influenced by military aircraft. Overall, we did not detect behavioral differences (i.e., time spent bedding, standing, foraging, traveling) between males and females. Pronghorn exposed to military activity, and those that were not, bedded the same amount of time. Pronghorn at BMGR foraged less and stood and traveled more than pronghorn not exposed to military activity. These trends were the same with and without anthropogenic activity. Only 7.3% of behavioral events occurred with identifiable stimuli. Military overflights occurred 363 times (0.8%) and non-military overflights occurred 77 times ( 10 m when ground stimuli were present. Ambient noise levels ranged up to 123.1 decibels (dB). The average sound pressure level on days with military activity was 65.3 dB compared to 35.0 dB without military activity. Because we obtained hearing tests from deer and pronghorn, we were able to develop an ungulate weighting filter on the noise generated from overflights of A-10 and F-16 aircraft. Desert ungulates do not hear sound pressure levels generated from these aircraft as well as humans do (i.e., 14–19 dB lower). The military activity we examined had only marginal influence on Sonoran pronghorn. Pronghorn used the ranges shared with the military throughout the year and behavioral patterns of pronghorn were similar with and without the presence of military stimuli. Furthermore, pronghorn behavior exposed to military activity was similar to behaviors of pronghorn not exposed to regular military activity. The auditory characteristics of pronghorn were similar for those that have and have not been exposed to military activity. The population of Sonoran pronghorn in the United States continues to decline and is in serious danger of extirpation. Clearly, additional work needs to be done, but military activity as measured herein is not a limiting factor.

Vegetative characteristics of urban land covers in metropolitan Tucson

In this study we developed a methodology that associated land cover categories to aerial photographs. We selected 4, 42-mile (10 km2) study sites within metropolitan Tucson, Arizona for our pilot study. Land uses within these sites covered the range of landscapes found within Pima County, Arizona, although not necessarily in proportions representative of the metropolitan area. We designated land cover categories within the pilot sites based on recent (March, 1990) aerial photographs and developed a geographical information system (GIS) database of these land cover categories. We measured vegetation attributes on randomly selected samples within each land cover category and classified vegetation occurring on specific land cover categories according to the Brown et al. (1979) system. Our land cover classification system was nominal with a hierarchical structure, facilitating organization and providing flexibility for adding new categories.Our results showed that although neighborhood parks contained the greatest vegetated areas within our four study plots, very low density housing (≥4 acres/house), rivers whose banks were partially stabilized, naturally occurring washes (with no bank stabilization), and natural open space contained the highest percentage of native vegetation. Within our four study sites, low density housing (≥4 acres/house), rivers with partially stabilized banks, naturally occurring washes (no bank stabilization), and natural open space land cover categories contained the most area that was covered with vegetation providing escape cover.

Sonoran pronghorn habitat use on landscapes disturbed by military activities

Abstract The Sonoran pronghorn (Antilocapra americana sonoriensis) population in the United States declined to ≤33 animals in January 2003. Low population numbers and unstable recruitment are concerns for biologists managing this subspecies. We examined habitat use by pronghorn from 1999 to 2002 on a portion of the Barry M. Goldwater Range (BMGR) used for military exercises. We overlaid locations of pronghorn (n=1,203) on 377 1-km2 blocks within the North (NTAC) and South Tactical Ranges (STAC), BMGR; we classified vegetation associations and disturbance status (e.g., airfields, targets, roads) for each block. Locations of pronghorn were distributed in proportion to vegetation associations on NTAC and STAC. Sightings of pronghorns were biased toward disturbed blocks, with 73% of locations of pronghorn occurring in proximity to mock airfields, high-explosive hills (e.g., targets for live high-explosive bombs and rockets), other targets, and roads. Disturbed landscapes on the BMGR may attract Sonoran pronghorn by creating favorable forage. Habitat manipulations simulating the effects of military disturbances on the landscape (e.g., improved forage) may improve remaining Sonoran pronghorn habitat.

Multiple use management: using a GIS model to understand conflicts between recreationists and sensitive wildlife

The management of natural resources involves the integration of physical, biological, and sociological information. Computerized geographical information systems (CIS) offer the capacity to combine this information. GIS has the potential to be a powerful wildlife management tool for integrating recreational and biological information. This study develops a recreational use model using data from a traditional recreational survey and a mountain sheep habitat model within a GIS database. This study develops a method that provides the resource manager with a toot to make predictions about the locations where recreational users may be encroaching on mountain sheep. Findings of this study illustrate that frequent recreational use along two trails occurred within preferred sheep habitat. More than 45% of recreationists surveyed travel extensively off the designated trails into the wilderness areas and thereby further encroach upon sheep habitat. This study demonstrates the use of a GIS to identify critical habit...

Introduction: management for the survival of Sonoran pronghorn in the United States

Wildlife Society Bulletin 2000, 28(4):5–xxx Peer refereed Historical population estimates of pronghorn (Antilocapra americana) in North America are as high as 60,000,000 (O’Connor 1939). In 2000 the population of pronghorn was estimated at 799,200 (Yoakum 2004). Currently there are 5 recognized subspecies of pronghorn based on differences in color, size, and form: American pronghorn (A. a. americana), Mexican pronghorn (A. a. mexicana), peninsular pronghorn (A. a. peninsularis), Oregon pronghorn (A. a. oregona), and Sonoran pronghorn (A. a. sonoriensis). However, recent genetic analyses have not revealed differences significant enough to retain these subspecies designations. Some suggest that a species decline is more legitimate than the 5 subspecies classified (Malone et al. 2002, O’Gara and Janis 2004). As genetic tools allow biologists to learn more about the genome of all species, classifications will evolve. However Sonoran pronghorn are eventually classified subspecifically, they will be protected under the Isolated Vertebrate Population Policy in the Endangered Species Act (United States Fish and Wildlife Service 1998). Current management of Sonoran pronghorn is also controversial (Paradiso and Nowak 1971, Cockrum 1981, United States Fish and Wildlife Service 1998, Malone et al. 2002, O’Gara and Janis 2004). The United States government listed Sonoran pronghorn as endangered in 1967. Since then, recovery efforts have been limited because much of Sonoran pronghorn habitat in the United States is inaccessible. Sonoran pronghorn historically ranged from eastern California into southeastern Arizona and south to Sonora, Mexico but are currently limited to <25% of their historical habitat in Arizona and northern Sonora, Mexico. Estimated numbers in the United States have been low since the early 1900s, ranging from approximately 100 in 1925 to <300 in 1998 (United States Fish and Wildlife Service 1998). However, during the current drought, numbers plummeted to <30 in 2002, and the subspecies was on the verge of extinction in the United States. The population of Sonoran pronghorn increased to <51 by December 2004 (J. C. deVos, Jr., Arizona Game and Fish Department, personal communication), but their survival is precarious and drastic and untested methods are ongoing to pull the subspecies from the brink of extinction. Aggressive management tactics including manipulation of forage and water availability and captive breeding have been initiated; efforts that some question. In the past decade, dedicated and determined individuals from the Arizona Game and Fish Department and the United States Fish and Wildlife Service initiated recovery efforts that had been proposed for nearly 3 decades. Those individuals (some of whom are authors and coauthors of the following papers) generated funds, interest,

Military jet activity and Sonoran pronghorn

SummaryForty percent of the habitat for the endangered Sonoran pronghorn (Antilocapra americana sonoriensis) in the United States is on the Barry M. Goldwater Range (BMGR), a bombing and gunnery range located in southwestern Arizona, USA. Wildlife and land managers have expressed concerns that military aircraft activity may be detrimental to Sonoran pronhom. We observed the response of Sonoran pronghorn to military jet activity from 4 vantage points, BMGR from February 1998 to June 2000. We obtained behavioral observations on 172 days and obtained 44,773 observation events (i.e., 1 observation / 30 seconds). Pronghorn were exposed to 109 direct military overflights, but only 6 were <305 m above ground level. Overall, behavior of males and females was not significantly different and the presence of military aircraft did not cause changes in behavior.ZusammenfassungVierzig Prozent des Lebensraums des gefährdeten Sonora-Gabelbockes (Antilocapra americana sonoriensis) in den USA liegen auf dem Barry M. Goldwater Range (BMGR), einem militärischen Schiessplatz und Bombenzielgeländc in Südwest-Arizona. Wildbiologen und Landespfleger sind darüber besorgt, dass sich der militärische Flugbetrieb nachteilig auf die Gabelböcke auswirken könnte. Von Februar 1998 bis Juni 2000 beobachteten wir von 4 Beobachtungspunkten auf dem BMGR aus die Reaktion von Sonora-Gabelböcken auf militärischen Düsenflugbetrieb. Die Verhaltensbeobachtungen fanden an 172 Tagen statt, und es wurden 44733 Einzelbeobachtungen gesammelt (1 Bobachtung/30 Sekunden). Die Gabelböcke waren 109 direkten überflügen durch Militärflugzeuge ausgesetzt, wovon allerdings nur 6 in weniger als 305 m Höhe über dem Boden stattfanden. Insgesamt unterschied sich das Verhalten von Männchen und Weibchen nicht signifikant voneinander, und die Anwesenheit von Militärflugzeugen rief keine Verhaltensänderungen hervor.

Bombing and Sonoran Pronghorn: A Clear and Present Danger?

Abstract The United States Air Force (USAF) uses part of Sonoran pronghorn (Antilocapra americana sonoriensis) habitat for bombing exercises (i.e., Barry M. Goldwater Air Force Range [BMGR], southwest AZ, USA) that could be detrimental to the endangered subspecies. To minimize injury or death to Sonoran pronghorn, the USAF and United States Fish and Wildlife Service developed a monitoring protocol that would eliminate live ordnance delivery in the vicinity of pronghorn. From 1998 to 2003, we searched for pronghorn on or near military targets prior to ordnance delivery. If we observed pronghorn within 5 km of a target, the target was closed for ≥24 hours. We monitored bombing ranges on BMGR and closed >5,000 targets for >1,000 days due to military activity. To our knowledge, no pronghorn were killed or injured. We recommend that the monitoring program continue as long as military activity occurs in pronghorn habitat.