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Locality records (dots) of Sciurus arizonensis in New Mexico. Numbers refer to locations listed in Appendix. Some dots represent more than one record. Shading represents elevations: white ,1,700 m; pale gray, 1,700-2,100 m; medium gray, 2,100-2,500 m; dark gray .2,500 m. Rectangular shading on inset map of New Mexico illustrates region of coverage.
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Little is known about the Arizona gray squirrel (Sciurus arizonensis), which is endemic to mid-elevation riparian habitats in Arizona, New Mexico, and Sonora. In New Mexico, previous compilations of specimen records were restricted to the San Francisco River drainage in western Catron County. We compiled information on museum specimens, literature...
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We investigated localities from which Eutamias atristriatus Bailey, 1913 (= Tamias minimus atristriatus) and Zapus luteus Miller, 1911 (= Zapus hudsonius luteus) were collected during a 1902 survey in the Sacramento Mountains, New Mexico, by the United States Biological Survey. The locality from which the holotype of Eutamias atristriatus was colle...
A compliance survey was conducted in July 2015 to determine presence of the New Mexico meadow jumping mouse (Zapus hudsonius luteus) within property owned by the city the Alamogordo near the upper end of Bonito Lake, Lincoln County, New Mexico. Riparian habitat consistent with the requirements of Z. h. luteus occurred within a wetland adjacent to B...
Citations
... Native Arizona gray squirrels (Sciurus arizonensis) and introduced Abert's squirrels (S. aberti) inhabit the Santa Catalina Mountains of southern Arizona, USA (Lange 1960). These two species may be syntopic (Brown 1984;Best and Riedel 1995;Frey et al. 2008). Each spe cies uses dreys and tree cavities for nests and protection (Brown 1984;Steele and Koprowski 2001) and consume similar foods that include cones and seeds, acorns, stami nate flowers, mistletoe, and fungi (Brown 1984). ...
... Arizona gray squirrels on the Santa Catalina Moun tains are rarely observed and thought to be in decline; however, not a single intensive study has ever been con ducted on the status of this species in any portion of their distribution with all concerns because of anecdotal infor mation. Once listed as a candidate species for protection as threatened under the U.S. Endangered Species Act in the Santa Catalina Mountains (Lange 1960;Frey et al. 2008), formal protection did not occur. Recently, modi fied fire regimes may be contributing to this decline since Arizona gray squirrels appear to use unburned riparian areas with dense understory (Brown 1984). ...
... In our study, Abert's squirrels appear to use a broader range of vegetation types after fire than native Arizona gray squirrels. Con versely, Arizona gray squirrels are a riparian obligate spe cies (Best and Riedel 1995;Frey et al. 2008) and lower elevations on the Santa Catalina Mountains were not as intensely burned as higher elevations. This may explain why the native species remains at lower elevations with dense understory in unburned and low burn severities but are no longer found at higher elevations. ...
Disturbance events can alter habitat properties, leading to species displacement, isolation, and/or local extinction. Therefore, understanding the interactions of potential ecological drivers on native and introduced wildlife species post-fire is critical to understand influences on distribution. We studied native Arizona gray squirrels (Sciurus arizonensis), which are believed to favor dense riparian habitat, and introduced Abert's squirrels (S. aberti), which prefer open ponderosa pine (Pinus ponderosa) forests. We examined how uncommon native Arizona gray squirrels and introduced Abert's squirrels used areas previously burned by widespread fires more than a decade prior to our study. To determine how past fire may affect squirrel habitat, we examined squirrel use and occupancy within fire altered habitats and used distance sampling to determine squirrel distribution, feeding, and nest use within a mosaic of burn severities. Occupancy and habitat use indicated that introduced Abert's squirrels readily used post-fire conditions more than native Arizona gray squirrels, likely due to the opening of a dense understory. Arizona gray squirrels remained in unburned riparian areas; therefore, fire affected riparian areas can be directly targeted for management to increase abundance of the native species.
... iucnredlist.org). Recent publications have provided muchneeded information on space use and ecology (Frey et al., 2008;Cudworth and Koprowski, 2010, 2011, 2013, yet no literature is available on survival and causes of mortality, although anecdotal reports suggest individuals may be killed by both mammalian and avian predators as well as through collisions with vehicles (Brown, 1984). A better understanding of survival and mortality is critical for conservation and management of this sensitive species. ...
Arizona gray squirrels (Sciurus arizonensis) are endemic to the southwestern United States and northwestern Mexico. Despite classification as a species of concern in portions of its range, little is known about Arizona gray squirrels. We investigated survival and causes of mortality for a population of squirrels in the Huachuca Mountains in 2007 and 2008. Adult survival was high and did not differ between sexes, with probability of survival >0.70 one year postcapture. Predation was the most common known cause of mortality; consequently, management plans should account for habitat characteristics that provide protection from predators when managing for Arizona gray squirrels.
... The herbaceous plants that occur in these communities tend to be more arid-adapted grasses and forbs. The Arizona gray squirrel (Sciurus arizonensis) is the only species of terrestrial mammal in the upper Gila River region that is strongly associated with riparian forest to the exclusion of other riparian associations (Frey et al. 2008), but it is also uses Madrean pine-oak forests (Cudworth and Koprowski 2011). ...
The region surrounding the upper Gila River watershed is one of two hotspots of mammal diversity outside of the tropics in North America. A total of 106 species of native, non-human mammals have been documented from the upper Gila River watershed, with 83 species in the Cliff-Gila Valley. Of the species known from the Valley, nearly half (41%) were categorized as either strongly associated or obligate to riparian habitats. Overall, the most important riparian habitat types for mammals were herbaceous. The mammal fauna of the upper Gila River watershed is in a state of ecological decline with a high rate of extirpation (9.4% of fauna), establishment of nonnative species, and an additional 50% of the mammal fauna at risk of population loss in the region. Ecological changes to riparian systems are more likely to result in wholesale loss of unique species and escalated destabilization of the system. Thus, it is essential to maintain and enhance riparian habitat to maintain mammal diversity in the region. Key flow-ecology relationships for mammals include:
American beavers (Castor canadensis) require perennial water with pools that exceed 1.0 m (3.28 ft) in depth. Reductions in frequency and magnitude of floods cause channel stabilization and narrowing which eliminates the secondary channels preferred by beavers on large rivers. Rapid fluctuation of flows, particularly during winter, can negatively impact beavers.
Muskrats (Ondatra zibethicus) require perennial water with deep pools (> 0.3 m [1 ft]). They require relatively stable flows, in part because this enhances production of emergent aquatic food plants. Reductions in frequency and magnitude of floods causes channel stabilization and narrowing which eliminates the secondary channels and ponded water preferred by muskrats.
New Mexico meadow jumping mice (Zapus hudsonius luteus) require well-developed herbaceous riparian vegetation on saturated soil. Loss of frequency and magnitude of moderate and large floods diminishes hydro-geomorphic processes that promote herbaceous vegetation. Reductions in base flows and loss of frequency and magnitude of elevated flows and small floods reduce the extent of wetted habitat during the crucial summer low flow and monsoon periods when the species is active above ground.
Terrestrial small mammal assemblages are best expressed in native early successional riparian habitats. Flow reductions lower groundwater levels that result in a decrease in abundance of hydrophilic species, which allows more drought-resistant species such as exotic saltcedar (Tamarix spp.) to outcompete native riparian species. Loss of peak flows causes loss of gravel bars and subsequent deposition of finer textured sediments above flood stage, which normally promotes mature cottonwood gallery forests to the exclusion of earlier successional stage herbaceous and willow-dominated communities preferred by the majority of aquatic and terrestrial mammals.
Bats utilize riparian systems for important life history functions, including access to free drinking water and the production of insect prey.
North American river otters (Lontra canadensis) require adequate perennial flow (> 35.31 cubic feet per second [cfs]) that provides abundant and diverse fish prey and dilutes pollutants. Flow regimes that benefit beavers also benefit otters.
... However, our estimates of squirrel density are expected to be maximal as we likely missed nests during radio-telemetry and consequently underestimated number of nests used per individual. Densities were higher in riparian than pine-oak woodlands, in agreement with scant existing information on the habitat of Arizona gray squirrels (Theobald 1983, Brown 1984, Hoffmeister 1986, Frey et al. 2008. Riparian areas may contain more tall trees suitable for nesting and provide an increased supply of drinking water and walnuts, suggested to be an important food item for Arizona gray squirrels (Theobald 1983;Brown 1984;Hoffmeister 1986; N. Cudworth and J. Koprowski, The University of Arizona, unpublished data). ...
Nests provide a place for individuals to rest, raise young, avoid predators, and escape inclement weather; consequently, knowledge of habitat characteristics important to nest placement is critical for managing species of conservation concern. Arizona gray squirrels (Sciurus arizonensis) are endemic to mountains of southwestern United States and northwestern Mexico. We investigated factors influencing nest-site selection at 4 spatial scales (forest-type, nest-site, nest-tree, and within-canopy placement) to provide ecological information and management recommendations for this sensitive species. Nest densities were 2.6 times higher in riparian than pine-oak woodlands. Nest sites had more large trees, snags, logs, and canopy cover and had lower slope. Arizona gray squirrels selected tall trees with more interlocking trees and tended to place nests adjacent to the main trunk. Regardless of scale, Arizona gray squirrels seemed to select nesting areas for their ability to provide protection from predators and the elements as well as access to food. Consequently, maintaining large trees with closed canopies and downed logs should be considered when determining land management plans. © 2011 The Wildlife Society.
... The Huachuca Mountains are believed to have among the highest densities (Brown 1984;Hoffmeister 1986). Despite a federal listing as threatened in Mexico due to habitat loss (Alvarez-Castañeda and Patton 1999), and sensitive by the United States Forest Service (S. a. catalinae- Best and Riedel 1995), little is known about the species, with only a single publication in the primary, ecological literature (Frey et al. 2008;Koprowski 2005 We focused our study in ,150 ha of oak-juniper (Quercus-Juniperus) forests of lower Huachuca Canyon at 1,555-1,860 m in an area with an ephemeral stream flowing from late summer through winter. Major tree species included Arizona white oak (Quercus arizonica), Emory oak (Q. ...
Space use frequently differs between sexes and may reflect differences in parental investment and limiting resources. We examined Arizona gray squirrels (Sciurus arizonensis) from April 2007 to December 2008 to determine effects of mating strategy on patterns of home-range size and overlap. Home ranges were large compared to those of congeners, suggesting an environment with low availability and predictability of resources, and differed by sex and season. Females maintained smaller home ranges overlapped more by males than females; overlap by male home ranges increased during the breeding season. Males had larger home ranges that overlapped females more than males; home-range size and overlap of both sexes increased during the breeding season. Additionally, male Arizona gray squirrels appear to respond to the distribution of females by enlarging home ranges to maximize proportion of females overlapped. Consequently, Arizona gray squirrels conform to theoretical predictions, with female space use influenced by access to food and male space use influenced by access to mates.
... The lowest elevation is 1,008 m Western New Mexico University Gila Natural History Collection, New Mexico State University Vertebrate Museum, University of Arizona Mammal Collection, and the National Museum of Natural History. My research on the mammals of the upper Gila region extends back more than 20 years and has involved general mammal surveys and reviews (e.g., Frey 1995Frey , 1996Frey , 2004Frey , 2007Frey and Yates 1996;Frey et al. 2006;Frey et al. 2007) and an array of species-specific studies (e.g., Ditto and Frey 2007;Frey 1989Frey , 1999aFrey , 1999bFrey , 2005Frey , 2008aFrey , 2008bFrey , 2008cFrey , 2009Frey and Burt 2001;Frey and LaRue 1993;Frey and Moore 1990;Frey et al. 1995;Frey et al. 2008). ...
The mammal fauna of the upper Gila River region is exceptionally
diverse. I documented 107 species of non-human
mammals in the region. Rodents constituted almost half the
species while bats and carnivores made up an additional
38%. Most species exhibited habitat specialization, with 42%
of species using only one or two biotic communities. Most
species that used only one biotic community were associated
with riparian habitats. The current fauna included only
one well-established exotic species, the house mouse (Mus
musculus), although there are isolated reports of feral goats
(Capra hircus) and feral pigs (Sus scrofa), and others are possible.
Ten species of native mammals were extirpated from
the region. I identified species at risk of population loss in
the study area as those that were determined to be rare and
facing potential threats. Species were classified into eight
rarity classes and four rarity ranks. Only 8% of the fauna
was in the most common category, while 16% of the fauna
was in the most rare category. The high proportion of rare
species in the Gila mammal fauna likely is a function of the
disjunct distribution of biotic communities and a high degree
of habitat specialization within the fauna. More than half of
species were facing potential threats, and species in the rarest
ranks also had a higher incidence of threats. In total, 50% of
the mammal fauna was found to be at risk of population loss
in the region. Although at-risk species were identified in each
order of mammals, rodents made up half the at-risk species.
Species at risk were more likely to be associated with higherelevation
biotic communities, particularly subalpine conifer
forest. General conservation and management efforts in the
upper Gila region may be most successful in maintaining
mammal diversity by focusing on riparian and high-elevation
conifer forest habitats. However, management to maintain or
enhance diversity will be challenging because specific species,
habitats, and geographic areas are likely to require independent
considerations. Formal conservation lists that guide
management do not fully reflect the scope of species’ risk of
population loss in this region. The methods developed in this
paper provide a quantitative approach for developing formal
conservation lists, such as Species of Greatest Conservation
Need in state wildlife conservation plans.
... Distributions of mammals change through time and are not static. Changes in habitat and climate have been implicated in the purported distributional shifts for some species (e.g., Dasypus novemcinctus-Humphrey 1974; Sorex cinereus, Microtuspennsylvanicus, Zapus hudsonius, and Mustela nivalis-Frey 1992; Sciurus niger-Geluso 2004b; Sigmodon fulviventer- Geluso et al. 2005), whereas others represent recently dis¬ covered populations because of lack of prior surveys (e.g., Peromyscuspectoralis-Geluso 2004a; Sciurus arizonensis- Frey et al. 2008). Additionally, some changes are related to misidentification of museum specimens (e.g., Peromyscus truei-Cook 1986; Leptonycteris nivalis- Hoyt et al. 1994), and others are the result of human introductions (e.g., Ammotragus lervia- Dickinson and Simpson 1980;S. ...
... The poor documentation of red squirrel distribution is somewhat surprising given that this species is generally conspicuous in mammalian faunas due to its diurnal behavior, distinctive vocalizations, and construction of prominent and distinctive middens. However, there has been little research on mammals of the Mogollon Plateau in New Mexico (Frey et al. 2008). I expect that the species' distribution in this region is even broader than the records presented herein. ...
In the American Southwest, the red squirrel (Tamiasciurus hudsonicus) occurs as disjunct populations in coniferous forests on mountaintops. There is a paucity of information concerning the species' distribution and habitat in western New Mexico. I report new records that document and verify the occurrence of red squirrels in additional montane areas in west central New Mexico, including the Mangas Mountains, Canovas Rim, Turner Mountain, Tularosa Mountains, Elk Mountains, Bearwallow Mountain, and Pinos Altos Mountains. I also report observations of red squirrels from an atypical habitat—low-elevation riparian forests. These new records suggest that the geographic distribution of the species in west central New Mexico is broader than indicated by existing records. However, I also document the apparent extirpation of red squirrels from the Zuni Mountains in northwestern New Mexico. The red squirrel is one of several avian and mammalian species associated with mixed coniferous forests that have become extirpated in this mountain range.
A study of the mammals of the Gila region of New Mexico was conducted from 2012 through 2020, with 2,919 voucher specimens collected through fieldwork and collaborations with commercial trappers, in addition to data from camera traps, review of major holdings at 46 museums (n = 12,505 georeferenced specimens), and literature review. Specimens cover a 170-year span, dating back to 1850 and were unevenly distributed spatially and temporally across the Gila region. Most areas were very poorly represented and when summed across all mammal species, ranged from 0.02 to 3.7 specimens per km2. The survey documented 108 species (104 now extant) for the region. High species richness, greater than that reported for 38 states in the United States, is likely due to the juxtaposition of multiple biomes in the Gila, including the Sonoran, Chihuahuan, and Great Basin deserts, the Rocky Mountains and Sierra Madre Occidental, and nearby “sky islands’’ of the Southwest. Two species, Leptonycteris yerbabuenae and Zapus luteus, are documented for the first time from the study area. Expansions of the known range of these species, and Sciurus arizonensis are described from specimen and camera data. Preliminary phylogeographic studies of four species (Notiosorex crawfordi, Neotoma albigula, Perognathus flavus, and Thomomys bottae) using the mitochondrial cytochrome-b gene reveal the dynamic biogeographic history of the region and reinforce how landscape complexity and climate change have jointly contributed to diversification and thus high mammalian diversity in the region.
The Balsas Basin is one of the largest and most varied formations in Mexico with a high degree of
endemism and variety of flora and fauna. To date, there has been no in-depth study of spider diversity in this
region. This paper details a survey of spiders found in the Balsas Basin, collected at 20 localities in the states of
Guerrero, Puebla, and Morelos between 1997 and 2011. During our survey, we identified 437 mature spiders
and grouped them into 24 families, 53 genera, and 56 species and sorted as follows: we found 15 species in
Guerrero, 29 in Morelos, and 20 in Puebla. We found five new country records for Mexico and 28 new state
records (nine for Guerrero, 10 for Morelos, and nine for Puebla), with a total of 13 possible new species. We
estimated beta diversity (change in species composition), and indicated that most localities shared only a few
species (fewer than 40%), which suggests that each locality has a unique suite of species with specific habitat
characteristics. This first report on spiders from this extensive region shows the necessity for further study in
the areas of biodiversity, ecology, and conservation biology.
