The Feasibility of Gray Wolf Reintroduction to the Grand Canyon Ecoregion Paul G. Sneed Environmental Studies , Master of Arts Program, Prescott College, 4906 Box Canyon Road, Billings, MT 59101; (406) 245-9117; (fax) (406) 245-0787; [email protected] Abstract As part of a regional conservation planning initiative, this study is being undertaken to determine the biophysical and socioeconomic feasibility of reestablishing a top carnivore, the gray wolf (Canis lupus), in the Grand Canyon Ecoregion (GCE). The GCE is a roughly 1.5 million km2 area located on the southern Colorado Plateau. The last remaining gray wolves were probably eradicated in the 1920s and 1930s. Because of an interest in restoring extirpated native species to this ecoregion, and the desire to increase the size of the gray wolf metapopulation in the Southwest, there is need for an objective and spatially explicit landscape-scale model of potential gray wolf habitat. The first phase of this conservation GIS analysis involves utilizing six habitat characteristics or factors—vegetation cover, surface water availability, prey density, human population density, road density, and land ownership—to identify and describe potential reintro- duction sites in the Arizona section of the Grand Canyon Ecoregion. Initial results show that there are at least two localities in northern Arizona suitable for reintroduction of around 100 wolves. This paper is a preliminary report on observations, results, and some recommendations deriving from the feasibility study. Introduction Crumbo 1998). This paper, how- Regardless of inaccuracies in the Conservation biologists have shown ever, will focus on current, prelimi- historical record, a partial picture of that large or top carnivores are often nary results from research done on where wolves occurred prior to their keystone species whose removal a limited number of factors in the extermination in the Southwest can jeopardizes the maintenance of eco- northern Arizona section of the still be pieced together. These records logical integrity in large-scale ecosys- ecoregion (see Figure 1). show that at least small populations tems (Soule and Noss 1998; Terborgh of wolves were found throughout the et al. 1999). Therefore, conservation Historic occurrence and woodlands and forests of northern planners interested in restoring and taxonomic position Arizona (Brown 1984). For example, protecting large ecosystems or To accurately reconstruct the his- from these records we know that there ecoregions emphasize recovery of top toric distribution of gray wolves in were at least 30 wolves on or near the predators. The primary goal of this the GCE is challenging for a vari- North Kaibab because of the number study—which is supported by the ety of reasons. Nineteenth century reported killed between 1907 and Grand Canyon Wildlands Council, writers often accidentally or pur- 1926 (Russo 1964). Brown (1984) Defenders of Wildlife, and Prescott posefully misidentified coyotes claimed that "the last wolf in this part College—is to determine the capabil- (Canis latrans), wolves, and wolf- of northern Arizona was taken on the ity and suitability (together, the fea- dog hybrids (Gipson et al. 1998). Paria Plateau about 1928", but a sibility) of reintroducing one top car- Wolf hunters and trappers some- former Civilian Conservation Corps nivore, the gray wolf (Canis lupus), times exaggerated the number of worker recently reported that he saw to the Grand Canyon Ecoregion wolves in an area to enhance their wolves on three different occasions (GCE) (Figure 1). job security and occasionally mis- in 1935 on the North Rim of Grand Ultimately, this study will ad- represented where a wolf was killed Canyon National Park (GCNP) dress 26 factors or aspects, grouped in order to claim a local bounty. (Leslie, personal communication). into two dimensions—biophysical Furthermore, the widespread use of Moreover, "as recently as March 3, and human—that are expected to af- poisons meant that many animals, 1948, assistant chief ranger A.L. fect the feasibility of wolf recovery including wolves, were dispatched Brown reported wolf tracks in fresh in the entire GCE (Sneed and without any record of their death. snow in the area of Bright Angel Vol. 18 No. 4 2001 Endangered Species UPDATE 153 contemporary molecular ge- to adequate food supplies, security netics (Wayne et al. 1992). from human disturbance and perse- Adopting this approach, cution are important factors affect- Nowak (1995) lumps the two ing the suitability of a landscape for previously identified GCE wolf recovery. At this stage in the wolf subspecies, (C. l. research, three critical human di- mogollonensis and C. l. mension aspects are considered: youngii), in with the geographi- human population density, road cally widespread subspecies C. density, and land status. l. nubilus. Nowak (1995) also affirms the validity of a truly Biophysical factors Southwestern subspecies, the Several reintroduction studies (e.g., Mexican wolf (C. l. baileyii), Mladenoff et al. 1995) suggest that which may have occupied or gray wolves, at least those living Figure 1. Grand Canyon ecoregion dispersed into the southeast- south of the Arctic, tend to prefer for- ern part of the GCE. ested landscapes. Historically, in the Southwest, wolves were most com- Point" on the North Rim of GCNP Habitat capability and monly found associated with wood- (Hoffmeister 1971). Finally, the last suitability mapping lands and montane forests (Groebner wolf inhabiting the Mogollon Rim Restoration of viable large carnivore et al. 1995; FWS 1996). When ob- area in the southern part of the GCE populations is probably among served elsewhere, such as in grass- was reportedly taken in 1942 society's greatest challenges, requir- lands, they were probably simply (Hoffmeister 1986). Clearly, gray ing extraordinary innovation and co- passing through as they moved be- wolves occurred within the Grand operative management on an tween their preferred habitat of for- Canyon Ecoregion well into the twen- ecoregional scale (Paquet and Hack- ested highlands. Figure 2 maps the tieth century, although their exact man 1995). Furthermore, solutions distribution of these two vegetation numbers and range will probably to large predator conservation are types, as well as others such as never be known with certainty. economic, sociological and political shrublands and grasslands. This fig- Due to the taxonomic splitting (human dimension issues), as well as ure plainly illustrates a broad band of approach of the time, Young and biological and ecological (biophysi- forestlands-woodlands extending Goldman (1944) identified 23 sub- cal factors) (Clark et al. 1996). The north-south from the Kaibab Pla- species of North American gray feasibility of wolf recovery depends teau, through the Flagstaff area to wolves (based on skull measure- on the capability and suitability of the Mogollon Rim, interrupted only ments, pelage color, and size) and habitat for sustaining wolf popula- by the Grand Canyon and urbanized mapped their geographic distribution. tions. Although many factors can and areas such as Flagstaff. Other ar- Two of these 23 nominal subspe- should be considered, the ultimate de- eas of woodland/forest vegetation cies—C.l. mogollonensis (the Ari- terminants are ungulate prey and hu- types are found in isolated moun- zona wolf), C.l. youngii (the Great man impact (Fuller et al. 1992) or, put tain areas of the Arizona Strip as Basin or Intermountain wolf), and, another way, sustenance and security. well as the Hualapai and Navajo possibly, C.l. baileyii (the Mexican Course screen landscape-scale Indian Reservations. wolf)—inhabited the Grand Can- habitat mapping for the Arizona por- Because wolves require large yon Ecoregion (Brown 1984; FWS tion of the GCE (see Figure 1) has amounts of water to aid digestion 1996). Development of similar been done following other similar (Lopez 1978; Mech 1970), several classification schemes continued studies (Mladenoff et al. 1995; studies of wolves in the Southwest into the 1970s (e.g., Hall and Quinby et al. 1999; Ratti et al. 1999; (Groebner et al. 1995; FWS 1996) Kelson 1959) until some taxono- Wydeven et al. 1998). Various bio- and elsewhere (Quinby et al. 1999) mists began questioning the split- physical factors can be considered in have suggested that the availability ting tradition of wolf taxonomy. evaluating the capability of habitat to of free water is an important deter- Modern lumping systems of wolf support wolves, but this study focuses minant of gray wolf abundance and taxonomy are based on multivariate on vegetation cover, surface water distribution. Figure 3 illustrates the statistical analysis of large sample availability, and, most importantly, distribution of currently mapped sizes and confirmed by the results of ungulate prey abundance. In addition lakes, springs, and streams in the Ari- 154 Endangered Species UPDATE Vol. 18 No. 4 2001 man population den- sity. Studies (e.g., Mladenoff et al. 1995; Ratti et al. 1999) have shown that lands with a hu- man population den- sity greater than 12 to 13 persons per square kilometer will not be suitable wolf habitat. The Figure 2. Vegetation cover Figure 3. Surface water map displayed in Figure 6 indicates zona portion of the Grand Canyon teau enjoys a very high density of that most of the Arizona section of Ecoregion. Although the digital data mule deer (eight to 13 animals per the Grand Canyon Ecoregion has available is very incomplete, this fig- km2), while the remainder of the area population densities less than 13 per- ure shows that there are more than has an adequate density of three to sons per km2. Except for the Flag- enough sources of surface water on eight deer per km2. The Coconino staff-Sedona urban zone, the entire the Kaibab Plateau, in the Flagstaff Plateau around Flagstaff also supports north-south corridor from the Kaibab area, and along the Mogollon Rim. quite dense populations (three to eight Plateau to the eastern, slightly urban- This conclusion is supported by the per km2).