(DRAFT) - Taxonomy
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
TAXONOMY
NAME - VOLE, HUALAPAI
OTHER COMMON NAMES - VOLE, HUALAPAI; VOLE, MEXICAN; VOLE, MEXICAN, HUALAPAI;MOUSE, MEADOW and HUALAPAI MOUNTAINS
ELEMENT CODE -
CATEGORY - Mammals
PHYLUM AND SUBPHYLUM - CHORDATA,
CLASS AND SUBCLASS - MAMMALIA,
ORDER AND SUBORDER - RODENTIA,
FAMILY AND SUBFAMILY - MURIDAE,
GENUS AND SUBGENUS - MICROTUS,
SPECIES AND SSP - MEXICANUS, HUALPAIENSIS
SCIENTIFIC NAME - MICROTUS MEXICANUS HUALPAIENSIS
AUTHORITY -
TAXONOMY REFERENCES -
COMMENTS ON TAXONOMY -
Hualapai Vole
Microtus mexicanus hualpaiensis Goldman, 1938
KINGDOM: Animal GROUP: Mammal
PHYLUM: Chordata CLASS: Mammalia
ORDER: Rodentia FAMILY: Muridae
Microtus mexicanus hualpaiensis is a small, cinnamon-brown,
mouse-sized mammal with a short tail and long, loose fur that nearly
obscures its small round ears. It appears thickset, blunt-nosed, and
short-legged. The mammae are 4; one pair pectoral, the other
inquinal. The 12 molar teeth (3 on each side of each upper and lower
jaw) are rootless, ever-growing and flat-crowned with enamel patterns
of alternating triangles. The skull is short, wide, relatively
angular, and sculptured. Characters which it shares with other
members of the species M. mexicanus and which separate it from other
members of the species Microtus in Arizona include: a shorter tail
(usually less than 34 mm and less than 29 percent of head and body
length); lighter (cinnamon-brown) fur; fewer mammae (2 pair rather
than 4); shorter skull; and shorter length of lateral ossifications of
the baculum (less than 1/3 breadth of stalk) (01).
This subspecies was described and named by E.A. Goldman in 1938
Taxonomy - 1 (DRAFT) - Taxonomy
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
from 4 specimens (type = No. 244108) collected on Hualapai Peak in
1923 and subsequently deposited in the U.S. National Museum,
Biological Survey Collection, Washington D.C. (02). Goldman (02)
considered the paler dorsal color, longer premaxillae, and slightly
shorter molar toothrows of this subspecies to distinguish it from its
closest relative, M.m. mogollonensis found along the Mogollon Rim of
central Arizona. Other than inclusion in species lists (03,04,05,06)
this animal has not been critically examined until recently when
Hoffmeister (01) noted that M.m. hualpaiensis could be distinguished
by its paler dorsal color, shorter body, shorter and broader skull,
and longer hind foot from M.m. mogollonensis and by its generally
larger size, longer tail, longer body and hind foot, broader skull
from M.m. navaho. He nevertheless considered it difficult to
characterize due to the small sample size (05). No systematic or
nomenclatural changes have been suggested for specimens from the
Hualapai's since Goldman first described the subspecies. In addition
to the four specimens at the National Museum, eight others have been
deposited at the University of Illinois Natural History Museum,
Urbana, Illinois and at the University of Arizona Mammal Collection,
Tucson, Arizona (07).
The taxonomy, and indirectly the distribution, of this subspecies
is complicated by two recent developments (07). First, Hoffmeister
(01) considered the subspecies hualaiensis poorly defined partly
because of the small sample size. Nevertheless, after reviewing two
specimens previously classified as M.m. mogollonensis from Prospect
Valley (about 90 miles northeast of the Hualapais) Hoffmeister
reassigned these specimens to M.m. hualpaiensis, pending a larger
sample size (01). He based this referral on body and skull
measurements that were closest to M.m. hualpaiensis. He suggested
further, that with a larger sample from the Hualapais,
M.m. hualpaiensis could "be better characterized or synonymized" and
that a larger sample from Prospect Valley might indicate that the two
specimens from there are referable to M.m. navaho to which on a
geographical basis they would seen referable (01).
Second, four specimens (skeletons without study skins) were
collected during 1981 from the Music Mountains, a previously unknown
locality about 50 miles north of Hualapai Peak and 55 miles southwest
of Prospect Valley (07). These specimens located in the University of
Arizona Mammal Collection, were identified as M. mexicanus; however,
they have not yet been identified to subspecies. No voles of any
species have been collected or reported from this area previously. It
is likely that because of its geographical proximity to the range of
M.m. hualapaiensis that it will be found to belong to that subspecies.
Geographically the Music Mountains are not only closest to the known
range of M.m. hualpaiensis, but are completely separated from other
subspecies by that range.
Taxonomy - 2 (DRAFT) - Status
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
STATUS
Coded Status
E: Federal Endangered
COMMENTS ON STATUS -
U.S. STATUSES AND LAWS:
The Hualapai vole (Microtus mexicanus hualpaiensis) has been
designated as Endangered pursuant to the Endangered Species Act of
1973 (50 CFR 17.11; P.L. 93-205, 87 Stat. 884; 16 U.S.C. 1531-1540),
as amended. The subspecies has this status wherever found including
the State of Arizona.
This subspecies is protected by the Lacey Act (P.L. 97-79, as
amended; 16 U.S.C. 3371 et seq.) which makes it unlawful to import,
export, transport, sell, receive, acquire, or purchase any wild animal
(alive or dead including parts, products, eggs, or offspring):
(1) in interstate or foreign commerce if taken, possessed,
transported or sold in violation of any State law or
regulation, or foreign law; or
(2) if taken or possessed in violation of any U.S. law,
treaty, or regulation or in violation of Indian tribal law.
It is also unlawful to possess any wild animal (alive or dead
including parts, products, eggs, and offspring) within the U.S.
territorial or special maritime jurisdiction (as defined in
18 U.S.C. 7) that is taken, possessed, transported, or sold in
violation of any State law or regulation, foreign law, or Indian
tribal law.
RESPONSIBLE FEDERAL AGENCIES:
USFWS -Responsible for the management/recovery, listing, and
law enforcement/protection of this species.
BLM -Responsible for the law enforcement/protection of this
species with applicable State and Federal laws on
public land under their control (43 CFR 4140). Also
responsible for management/recovery on Bureau of Land
Management lands.
All Federal agencies have responsibility to ensure that any
action authorized, funded, or carried out by that agency is not likely
to jeopardize the continued existence of the species or result in the
destruction or adverse modification of Critical Habitat (50 CFR 402),
and to utilize their authorities to carry out programs for the
conservation of the species.
STATE STATUSES AND LAWS:
STATE: Arizona
DESIGNATED STATUS: Group 2, Threatened Native Wildl. in Ariz.
Status - 1 (DRAFT) - Status
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
ADMINISTRATIVE AGENCY: Arizona Game and Fish Department.
STATE STATUTE: Ariz. Rev. Stat., Sec. 17-231(B)7.
INTERNATIONAL STATUSES, TREATIES, AND AGREEMENTS:
None.
ECONOMIC STATUSES:
This species has a value to society as a living wild subspecies
of Microtus mexicanus and needs to be maintained as such.
82/12/30:47 FR 58454/58460 - Notice of review
85/09/18:50 FR 37958/37967 - Revised notice of review
87/01/05:52 FR 00306/00309 - Proposed rule - Endangered
87/10/01:52 FR 36776/36780 - Final rule, listed as Endangered
Status - 2 HABITAT ASSOCIATIONS
HABITAT - TERRESTRIAL
INLAND AQUATIC
SOCIETY OF AMERICAN FORESTRY TYPES
SAF TYPE STAGE CLOSURE
Interior Ponderosa Pine shrub--seedling
Interior Ponderosa Pine young tree
Interior Ponderosa Pine mature tree
Interior Ponderosa Pine Old Growth
LAND USE -
Shrub and Brush Rangeland
Evergreen Forest Land
Mixed Forest Land
Forested Wetland
Nonforested Wetland
NATIONAL WETLAND INVENTORY CODES
NWI NWICLS NWIMOD NWISPEC
Palustrine SS6
Palustrine EM1
COMMENTS ON HABITAT ASSOCIATIONS -
In the Hualapai Mountains, Microtus mexicanus hualpaiensis has
been found between elevations of about 5200 and 8400 feet primarily
associated with conifer forest (07). Voles found in 1984 occupied
narrow strips of moist grass-sedge along permanent or semi-permanent
water from springs and seeps at the lower edge of ponderosa pine
forest and the upper edge of chaparral (07). Localities where voles
found in the 1960s and 1970s, but not in the 1980s, were primarily
associated with open ponderosa pine-Gambel oak forest in either open
forest floor or shrubby openings and not in association with springs
or seeps (07). At one locality, sign was found in aspen stands among
ponderosa pine and mixed conifer forest where, at the time, the soil
was wet with good grass cover or mat-like moss (07).
Relatively little ground vegetation appears to be common to all
vole sites. Where ground cover was measured, substrate without
vegetation ranged from 57 to 83 percent, but was usually 60 to 70
percent (07). At sites examined in 1984, all of which were associated
with water, grass, grass-like plants, and forbs accounted for about
24 (11-32 percent) percent coverage at ground level and grass and
grass-like plants averaged about 14 inches tall (07). At other
localities vegetation cover measurement techniques were different but
were roughly comparable. One locality in open ponderosa pine-Gambel
oak averaged only 3.4 percent coverage of vegetation up to 12 inches
high (07). Soils in the Hualapai's, mostly derived from gneiss and
granite, are generally coarse, shallow, and subject to erosion, which
when combined with poor land use results in unstable conditions for
the development and continuance of grass/forb habitats along
watercourses (07).
Nothing is known about burrow and nest requirements except that
runways, both underground and on the surface, often follow abandoned
and sometimes collapsed gopher burrows (07). Downed logs and rotting
stumps can provide both a cover from above (where runways maybe
adjacent or under logs) and cover for burrow entrances (02).
Habitat Associations - 1 Grasses, sedges, and forbs occurring in wetter vole habitat in
the Hualapai's include: a grass (Polypogon); sedge (Carex);
spikerushes (Eleocharis); rushes (Juncos); monkeyflowers (Mimulus);
smartweed (Polygonum); willowweed (Epilobium); meadow rue
(Thalictrum); geranium (Geranium); and dock (Rumex) (07). In drier
habitats occupied by voles large clumps of deer grass (Muhlenbergia
rigens) with waterweed (Baccharis sergiloides) or Emory baccharis
(B. emoryi) were found (07). Other woody plants scattered along the
water courses included the vine, canyon grape (Vitus arizonicus), and
the shrubs, snowberry (Symphoricarpos), wild rose (Rosa), buckthorns
(Rhamnus), and coyote willow (Salix lasiolepsis) (07). Trees found
occasionally in creek bottoms with vole habitat included: Arizona
walnut (Juglans major); ponderosa pine (Pinus ponderosa); and pinyon
pine (P. edulis) (07).
Of the habitats occupied by M.m. hualpaiensis in the Hualapai's
the grass-forb habitats along watercourses seems to be the most
important because it is only in the vicinity of such isolated and
undisturbed areas that ground cover can maintain itself (07). Because
of the many years of poor land practices and the continuing heavy
grazing, ground cover cannot develop or maintain itself elsewhere
except possibly in some places in years of good rainfall or
non-grazing. Thus, Spicer et al. (07) suggest that due to current
land use patterns other habitats where voles have been found are only
marginal for the vole and have been occupied only during better years.
In the Music Mountains M. mexicanus subsp. was found in one
locality among shrubs in a pinyon-juniper community. A second
locality consisted of a sagebrush community with some grass (07). In
the Music Mountains the pinyon-juniper locality showed about
36 percent of the vegetation to be 1 to 26 inches tall and 90 percent
of the sagebrush locality vegetation was 0 to 26 inches tall (07).
In the Music Mountain species found at one of the localities
included: single-leaved pinyon pine (Pinus monophylla; one-seed
juniper (Juniperus monosperma); manzanita (Arctostaphylos); and shrub
live oak (Quercus turbinella) (07). Vegetation at the other Music
Mountain locality included: big sagebrush (Artemesia tridentata) and
big galleta (Hilaria rigida) (07).
Note: These habitat associations for the Music Mountains are not
included in the habitat keyword items because the taxonomic status of
these individuals have not been determined.
Habitat Associations - 2 (DRAFT) - Food Habits
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
FOOD HABITS
TROPHIC LEVEL -
HERBIVORE
LIFESTAGE FOOD FOOD PART
General Roots/Tubers/Rhizomes-Herbaceous
General Roots/Tubers/Rhizomes-Woody
General Deciduous Shrubs-Leaves/Twigs
General Deciduous Shrubs-Flowers/Fruit/Seed
General Evergreen Shrubs-Leaves/Twigs
General Evergreen Shrubs-Flowers/Fruit/Seed
General Arthropods
General Vascular Plants-Emergent Nonwoody
General Poaceae
General
General Forb Leaves/Stems
General Forb Flowers/Fruit/Seed
Food Habits - 1 (DRAFT) - Environment Associations
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
ENVIRONMENTAL ASSOCIATIONS
G = General A = Adult
LIM = Limiting RA = Resting Adult
J = Juvenile FA = Feeding Adult
RJ = Resting Juvenile BA = Breeding Adult
FJ = Feeding Juvenile P = Pupae
L = Larvae E = Egg
RL = Resting Larvae
FL = Feeding Larvae
LIFESTAGE ENVIRONMENTAL ASSOCIATIONS
G
G Aquatic Features: Springs [flowing]
G Terrestrial Features: Burrows
G Terrestrial Features: Downed logs
Environment Associations - 1 (DRAFT) - Life History
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
LIFE HISTORY
FOOD HABITS:
There is virtually no information on food habits of Microtus
mexicanus hualpaiensis. In 1984, in the Hualapai Mountains, vole
runways contained cuttings of grasses and grass-like plants and bright
green fecal pellets (an indication of feeding on green vegetation)
(07). Another subspecies of Mexican vole, M.m. navaho, living in
similarly arid conditions (Navajo Mountain) with little ground cover
other than patches of heavily browsed shrubs, cut stems of buckbrush
(Ceanothus) and snowberry (Symphoricarpos) and was though to have been
feeding on the leaves of snowberry (08). Microtus in other places eat
a great variety of plant parts and species, but green, succulent
vegetation seems to be the most important (09). In winter, if green
vegetation is scarce, the Hualapai vole likely does as other Microtus
do by eating dead vegetation, roots and bark of shrubs and trees,
fungi, carrion, and excavated insect pupae (10,11). Fresh green
vegetation, shown to stimulate breeding in M. montanus by increasing
ovarian activity and uterine hypertrophy (12,13,14), may through its
effect on reproduction have an important influence on the population
and distribution of M.m. hualpaiensis (07). During times of drought
or of habitat degradation due to poor land use, the lack of poor
quality fresh green vegetation could result in a low level of
successful reproduction. Conversely, increased fresh plant growth
during periods of increased precipitation could contribute to the
increase and expansion of vole populations (07).
HOME RANGE/TERRITORY:
Other than the presence of extensive interconnected networks of
runways which indicate some degree of coloniality (07), nothing is
known about home range and territory in Microtus mexicanus
hualpaiensis. Home ranges among other species of Microtus are mostly
stable (i.e., center of activity and shape are similar day after day),
but depending on environmental and social conditions may include
variable (shape and center of activity varies day to day but remains
mostly in the same area over the long term) and shifting (center of
activity moves significantly from one area to another) home ranges
(15). Territoriality varies greatly in other species of Microtus. It
may be exhibited by males, females, pairs, or communally and may
change withina population depending on season or on environmental or
population conditions (15). Territoriality is expressed through
aggressive behaviors establishing dominance over other individuals or
obtaining access to an area in dispute. When females show these
behaviors they exhibit more non-contact threat displays than males
(16).
PERIODICITY:
Microtus mexicanus hualpaiensis is active both day and night:
having been seen or trapped during both the daylight hours and during
the night (07). They are probably similar to other Microtus in being
active during all parts of the year, including under snow cover.
Madison (15), summarizing for voles in general, described 2-6 hours
rhythms of activity and suggested they are related to food quality
Life History - 1 (DRAFT) - Life History
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
and energy needs.
MIGRATION PATTERNS:
Microtus mexicanus hualpaiensis is not known to be migratory nor
are any of the other subspecies of M. mexicanus.
COVER/SHELTER REQUIREMENTS:
Microtus mexicanus hualpaiensis belongs to a species that,
although occupying a great variety of mesic to xeric habitats, is most
commonly associated with dry, grass/forb areas associated with
ponderosa pine forests (01,17). In the Hualapai Mountains, most such
grass/forb ground cover appears to either have been replaced by coarse
perennials (e.g., goldenrod, Solidago) or to be restricted to small
areas with at least small amounts of permanent water (07). When such
grassy areas are not grazed or otherwise disturbed they may be
occupied by voles (07). Such areas provide both food items and cover
protection from predators. The smallest such area with active sign
consisted of 0.07 acres and contained bunches of deer grass (07).
Relatively little ground vegetation appears to be common to all
vole sites. Where ground cover was measured, substrate without
vegetation ranged from 57 to 83 percent, but was usually 60 to 70
percent (07). At sites examined in 1984, all of which were associated
with water, grass, grass-like plants, and forbs accounted for about
24 (11-32 percent) percent coverage at ground level and grass and
grass-like plants averaged about 14 inches tall (07). At other
localities vegetation cover measurement techniques were different but
were roughly comparable. One locality in open ponderosa pine-Gambel
oak averaged only 3.4 percent coverage of vegetation up to 12 inches
high (07). Soils in the Hualapai's, mostly derived from gneiss and
granite, are generally coarse, shallow, and subject to erosion, which
when combined with poor land use results in unstable conditions for
the development and continuance of grass/forb habitats along
watercourses (07).
Nothing is known about burrow and nest requirements except that
runways, both underground and on the surface, often follow abandoned
and sometimes collapsed gopher burrows (07). Downed logs and rotting
stumps can provide both a cover from above (where runways maybe
adjacent or under logs) and cover for burrow entrances (02).
REPRODUCTIVE SITE REQUIREMENTS:
Nothing is known of these requirements for Microtus mexicanus
hualpaiensis. They may, however, build nests of grass, sedges, or
rushes located along runways, under rocks, logs or stumps as do other
subspecies of Microtus (16).
REPRODUCTIVE CHARACTERISTICS:
There is little data on reproduction in the Hualapai vole.
Spicer et al. (07) found one pregnant female and one that appeared to
have just given birth, both in late May. On Black Mesa, La Rue (18)
found M. mexicanus pregnant from mid-March to mid-May. Brown (19)
working near Flagstaff found pregnant females from mid-April to early
May. Hoffmeister (01), collecting throughout Arizona, reported
pregnant M. mexicanus during April through August, although he noted
Life History - 2 (DRAFT) - Life History
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
that there were many months for which he did not have specimens.
Conley (20), cited in Keller (21), reported M. mexicanus breeding in
New Mexico from May through November. The gestation period for
M. mexicanus is unknown. For other species of Microtus, however, it
varies from about 20 to 24 days (22).
Microtus mexicanus hualpaiensis probably has a small litter size,
as do other M. mexicanus. In contrast to the 4 pairs of mammae of
most Microtus all M. mexicanus have only 2 pair, thus limiting the
number of young that can be nursed. Hoffmeister (01) found a mean of
2.51 (range = 6) embryos in 49 female M. mexicanus from Arizona.
Brown (19) reported a mean of 2.23 (1-3) embryos for 22 females from
Arizona. La Rue (18), working on Black Mesa, found a mean of 2.33
embryos (1-3) for 6 females. Keller (21), summarizing numerous
studies and localities, reported mean litter size in M. mexicanus
ranging from 1.6 to 3.11 (1-6). Among temperate voles, only
M. pinetorum has a smaller litter size (21).
The time of sexual maturity, first mating, and first conception
is not known for this subspecies nor for M. mexicanus as a group.
Nadeau (22) has summarized some of the literature on some of these
characteristics for other Microtus. Males achieve sexual maturity at
weights ranging from 25 to 41 grams and mate for the first time at 42
to 60 days of age. Females achieve sexual maturity at weights of 13
to 100 grams and may mate for the first time at ages between 14 and
105 days. Noting that the first mating may be sterile, Nadeau (22)
points out that the first litter may not be produced until 60 to 100
days of age. He also notes that sexual maturity may occur earlier or
at different times in different years and that when it occurs depends
on a variety of factors; nutrition and social conditions being among
the more important (22). Mating systems of M. mexicanus are not
known, however, other Microtus have been found to be promiscuous,
polygynous, or rarely, monogamous, or exhibiting various combinations
(16).
Although nothing is known about the reproductive potential of
M. mexicanus it is high for most other Microtus. Seabloom (23) points
out that reproductive efficiency in voles is maximized through estrus
being induced by pheromones in male urine and ovulation being induced
by copulation. Further, among voles as well as among other microtines
a post-partum estrus 1 to 4 days after parturition is typical and
sometimes estrus and ovulation may even occur on the same day as
parturition (23). This helps to explain the high productivity
described in Bailey's (24 in 11) report of 17 litters (83 young)
produced by one captive female M. pennsylvanicus and 13 litters (78
young) produced by her daughter and both occurring during a single
year or less. Fewer mammae, smaller litter size, and no evidence of
large population irruptions suggest, however, that M. mexicanus may
not have as high a reproductive potential as other species of
Microtus.
PARENTAL CARE:
Nothing is known about parental care in Microtus mexicanus
hualpaiensis nor in the species M. mexicanus. Wolff (16) has
summarized literature on this subject for other Microtus. Males do
not usually take part in caring for the young, however, there are
Life History - 3 (DRAFT) - Life History
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
exceptions among some species. In several species the males were
reported to groom, retrieve, and brood the young. They have also been
reported to build a second nest and brood part of the litter there
while the female brooded the rest of the litter in the primary nest.
Cannibalization by males of nestlings not their own has also been
reported.
POPULATION BIOLOGY:
The population biology of Microtus mexicanus hualpaiensis is
poorly known, nor is it much better known for the species. Current
limiting factors appear to be related to lack of ground vegetation
throughout the Hualapai Mountains (07). Grass/forb and grass/sedge
habitats that can support voles appear to be limited to a few small,
ungrazed areas at permanent or semi-permanent springs and seeps. As
noted in the section on REASONS FOR STATUS, such areas are few,
restricted, and highly vulnerable. It is possible that in good years
if ground vegetation has the opportunity to develop that the voles are
then able to move out from their refugia and expand into new areas.
While very small numbers of voles have been found away from the known
suitable localities these may have been young, recently dispersed,
individuals or otherwise small, temporary populations (07).
Taitt and Krebs (24) have summarized literature on vole
population dynamics and cycles. They found that among North American
Microtus, 3 demographic patterns prevail: "annual fluctuations,
multi-annual cycles, and both, in sequence." The first, annual
fluctuations, appeared to be the most common. Data from a 61 week
study of M. mexicanus and M. longicaudus (20, cited in 21) suggested
that the M. mexicanus pattern is one of annual fluctuations (21,24).
The sex ratio of M.m. hualpaiensis based on all specimens and
individuals handled from the Hualapais, Musics, and Prospect Valley at
100:70 (10 males and 7 females) favors males (07). This is likely too
small a sample to reliably reflect the actual sex ratio in
M.m. hualpaiensis.
Longevity and mortality in M.m. hualpaiensis is not known;
however, relatively few Microtus live past 1 year. For example, in
M. pennsylvanicus (with a higher reproductive potential than
M. mexicanus), one study indicated a 100 percent mortality rate for
animals at about 17 weeks (11). Another study indicated that
M. townsendii males had a life expectancy of about 21 weeks and
females of about 20 weeks (11). In the M. pennsylvanicus study
mortality rates ranged from 61 to 53 percent for each of several age
groups: post nestling juveniles, young adults, and older age groups.
Also, the lowest mortality was during winter and the highest during
summer (11). Such characteristics vary, no doubt, depending on
species and local conditions.
In suitable circumstances recovery potential should be good (07)
due to the inherent capacity of microtines to respond to favorable
environmental conditons (11). Favorable conditions include:
increased precipitation; reduced disturbances such as grazing;
improved land management practices; and any other factors encouraging
the growth and spread of grasses, sedges, forbs, and the like (07).
SPECIES INTERRELATIONSHIPS:
Life History - 4 (DRAFT) - Life History
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
No direct casual relationships involving Microtus mexicanus
hualpaiensis are known. No other microtine species occur within the
known range of this vole and none of the other small mammal species
sympatric with it are known to have such a relationship with it (07).
OTHER LIFE HISTORY DESCRIPTORS:
So little is known of the life history of Microtus mexicanus
hualpaiensis that there are no pertinent parameters to be described at
this time.
Life History - 5 (DRAFT) - Management Practices
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
MANAGEMENT PRACTICES
RESULT MANAGEMENT PRACTICE
Beneficial Suppressing wildfire
Beneficial Controlling/Restricting Off-Road Vehicles
Beneficial Maintaining/Controlling Water Flow
Beneficial Land Acquisition
Beneficial Water Right Acquisition
Beneficial Reforestation
Beneficial Maintaining Later Stages of Succession
Beneficial Controlling/Removing Domestic Animals
Adverse Off Road Vehicles
Existing Off Road Vehicles
Adverse Hiking/Camping
Existing Hiking/Camping
Adverse Climate Alteration
Existing Climate Alteration
Adverse
Existing
Adverse Food Supply Reduction
Existing Food Supply Reduction
Adverse Low Gene Pool
Existing Low Gene Pool
Adverse Underground Mines
Existing Underground Mines
Adverse Rural Residential/Industrial Areas
Existing Rural Residential/Industrial Areas
Adverse Recreational development
Existing Recreational development
Adverse Highway/Railroads
Existing Highway/Railroads
Adverse Siltation
Existing Siltation
Adverse Exotic/Feral/Introducted Species
Existing Exotic/Feral/Introducted Species
Adverse Erosion
Existing Erosion
Adverse Grazing
Existing Grazing
Adverse Vegetation Composition Changes
Existing Vegetation Composition Changes
Adverse Forest Alteration
Existing Forest Alteration
COMMENTS ON MANAGEMENT PRACTICES -
The current status of Microtus mexicanus hualpaiensis is the
result of the cumulative impact of past geological and climatological
events that restrict it to the mixed conifer and ponderosa pine
habitats of the Hualapai Mountains plus past and recent human-related
activities (07). Isolation, habitat restriction, and population
restrictions within the Hualapai Mountains have been the result of
Management Practices - 1 (DRAFT) - Management Practices
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
past climatic changes and Pleistocene glaciations resulting in
disjunct, relict populations of conifer forest communities and their
component parts which include this vole. Some component species, both
plant and animal, have probably gone extinct as environmental
conditions changed over thousands of years; nevertheless,
M.m. hualpaiensis populations, among others, persisted. Human-related
activities have speeded up the natural process of restriction and
fragmentation of habitat. The reduction and elimination of ground
vegetation appears to be the primary reason for endangerment. Loss of
ground cover resulting from land use practices such as road and
recreational facilities construction, camping, off-road vehicle
activity, mining, and livestock grazing has compounded natural
problems of steep slopes, erodable granite soils, and a dry and
variable climate. With the loss of ground vegetation, or its
replacement with coarse apparently unpalatable perennials, food and
cover for this animal were also lost. The vole has apparently
retreated to the few remaining areas where cover can still be found.
Such areas are located around surface water that have not been or are
not frequented by livestock. In such places, small populations of
voles subsist and perhaps, when the conditions are right, disperse to
colonize a grassy or grass/forb area resulting from a year with high
precipitation and no disturbance (07).
The known areas of habitat where the Hualapai vole is found
presently are small enough that any one of them could be: eliminated
by a few head of livestock grazing for a week; severely damaged by
erosion and deposition resulting from a heavy rain after months of
drought; or severely damaged by fire, pollution or irresponsible
actions of recreationists, road builders, miners, or ranchers.
UNAPPROVED PLAN:
There is no recovery plan for the Hualapai vole at the current time.
Initiation of the plan is scheduled for fiscal year 1988.
Recommendations made in a 1985 status report will likely form the
basis of a recovery effort. That report recommends maintaining and
enhancing present populations and habitats by:
1) fencing water and surrounding areas where voles or their
sign occur to protect the habitat from off-road vehicle
disturbance and cattle grazing;
2) when springs/seeps are developed, leave enough free-flowing
water to support ground vegetation during the dry season
(June) and place livestock troughs away from stream
bottoms;
3) prevent channel cutting or sanding-in by preventing soil
disturbances and encouraging revegetation upstream and
upslope in order to rehabilitate habitat;
4) filing for water rights where appropriate;
5) controlling livestock use to improve and recover riparian
vegetation, and;
6) acquire important habitat that is currently privately
owned.
Management Practices - 2 (DRAFT) - Management Practices
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
Restricting livestock access through fencing of north slopes
adjacent to streams could provide additional suitable habitat for the
voles. Habitat in Hualapai County Mountain Park could be improved by:
1) fencing boundaries to exclude livestock,
2) enclosing waters and immediately adjacent areas,
3) initiation of an erosion prevention and recovery program by
rehabilitating and revegetating the habitat,
4) continuing to exclude ORV's and,
5) allowing charcoal fires only to reduce chances of
wildfires.
Biological investigations should continue and include:
1) intensive searches of permanent water and grass-forb areas
above 1640 m for additional populations and potential
habitat in the Hualapai and Music Mountains and Prospect
Valley,
2) surveys in other potentially suitable mountainous areas in
northwest Arizona,
3) taxonomic studies of the Music Mountain specimens and any
new populations that may be found,
4) initiation of life history, food habits, ecology, and
population studies of the Hualapai vole to gain
understanding of adaptive, reproductive, dispersal and
resource utilization strategies, and
5) initiation of detailed studies of the history, composition,
role of fire, and the development of natural ground
vegetation.
Finally, public awareness, appreciation, and support for
preservation of the Hualapai vole must be encouraged.
Management Practices - 3 (DRAFT) - References
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
References
***** REFERENCES FOR ALL NARRATIVES EXCEPT N-OCCURRENCE *****
01 Hoffmeister, D.F. 1986. Mammals of Arizona. Univ. of Ariz. Press
and Arizona Game and Fish Dept. Tucson. xx + 602 pp.
02 Goldman, E.A. 1938. Three new species of Microtus mexicanus.
Jour. Mamm. 19:493-495.
03 Hall, E.R., and E.L. Cockrum. 1953. A synopsis of the North
American microtine rodents. Univ. of Kansas Publs. Mus. Nat. Hist.
5(27):373-498.
04 Miller, G.S., Jr., and A.R. Kellogg. 1955. List of North American
recent mammals. Bull. U.S. Nat. Mus. xxii + 954 pp.
05 Cockrum, E.L. 1960. The recent mammals of Arizona: Their
taxonomy and distribution. Univ. Arizona Press, Tucson. 276 pp.
06 Hall, R.R. 1981. The mammals of North America. Second Edition
Vol. II. John Wiley and Sons, New York. pp. 601-1181.
07 Spicer, R.B., R.L. Glinski, and J.C. deVos, Jr. 1986. Status of
the Hualapai vole (Microtus mexicanus hualpaiensis) Goldman. Rev.
Unpubl. Ariz. Game and Fish Dept. Rept. to U.S. Fish and Wildl.
Serv., Endang. Species, Albuquerque, NM. vi + 49 pp.
08 Benson, S.B. 1935. A biological reconnaissance of Navajo Mountain
Utah. Univ. Calif. Publs. Zool. 40(14):439-456.
09 Batzli, G.O. 1985. Nutrition. IN: Biology of New World
Microtus. R.H. Tamarin, Ed. Amer. Soc. Mammal. Spec. Publ. No. 8.
pp. 779-811.
10 Cahalane, V.H. 1961. Mammals of North America. Macmillan Co.,
New York.
11 Johnson, M.L., and S. Johnson. 1982. Voles (Microtus species).
IN: J.A. Chapman and G.A. Feldhamer, Ed. Wild animals of North
America. Johns Hopkins Univ. Press. Baltimore, MD. pp. 326-354.
12 Negus, N.C., and A.J. Pinter. 1966. Reproductive responses of
Microtus montanus to plants and plant extracts in the diet. Jour.
Mammal. 47(4):597-601.
13 Berger, P.J., and N.C. Negus. 1974. Influence of dietary
supplements of fresh lettuce on ovariectmized Microtus montanus.
Jour. Mammal. 55(4):747-750.
14 Negus, N.C., P.J. Berger, and L.G. Forslund. 1977. Reproductive
strategy of Microtus montanus. Jour. Mammal. 58(3):347-353.
15 Madison, D.M. 1985. Activity rhythms and spacing. IN: Biology
of new world Microtus. R.H. Tamarin, Ed. Amer. Soc. Mammal. Spec.
Publ. No. 8. pp. 373-419.
16 Wolff, O. 1985. Behavior. IN: Biology of new world Microtus.
R.H. Tamarin, Ed. Amer. Soc. Mammal. Spec. Publ. No. 8.
pp. 340-372.
17 Findley, J.S., A.H. Harris, D.E. Wilson, and C. Jones. 1975.
Mammals of New Mexico. Univ. New Mex. Press. Albuquerque, NM.
xxii + 360 pp.
18 La Rue, C.T. 1986. Notes on a new Mexican vole (Microtus
mexicanus) population from northeastern Arizona. Unpubl. Ms. Game
and Fish Dept. files, Phoenix.
19 Brown, L.N. 1968. Smallness of mean litter size in the Mexican
vole. Jour. Mammal. 49(1):159.
References - 1 (DRAFT) - References
Species VOLE, HUALAPAI
Species Id ESIS052006
Date 14 MAR 96
20 Conley, W. 1976. Competition between Microtus: A behavioral
hypothesis. Ecol. 57:224-237.
21 Keller, B.L. 1985. Reproductive patterns. IN: Biology of new
world Microtus. R.H. Tamarin, Ed. Amer. Soc. Mammal. Spec. Publ.
No. 8. pp. 725-778.
22 Nadeau, J.H. 1985. Ontogeny. IN: Biology of new world Microtus.
R.H. Tamarin, Ed. Amer. Soc. Mammal. Spec. Publ. No. 8.
pp. 254-285.
23 Seabloom, R.W. 1985. Endocrinology. IN: Biology of new world
Microtus. R.H. Tamarin, Ed. Amer. Soc. Mammal. Spec. Publ.
No. 8. pp. 685-724.
24 Taitt, M.J., and C.J. Krebs. 1985. Population dynamics and
cycles. IN: Biology of new world Microtus. R.H. Tamarin, Ed.
Amer. Soc. Mammal. Spec. Publ. No. 8. pp. 567-620.
***** REFERENCES FOR N-OCCURRENCE NARRATIVE ONLY *****
01 Spicer, R.B., R.L. Glinski, and J.C. deVos, Jr. 1986. Status of
the Hualapai vole (Microtus mexicanus hualpaiensis Goldman).
Revised. Unpubl. AZ Game and Fish Dept. Rept. to U.S. Fish and
Wildl. Serv., End. Species, Albuquerque, NM. vi + 49 pp.
02 Peck, R. 1986. Pers. comm. Bureau of Land Mgmt., Kingman Res.
Area, Kingman, AZ.
03 Hall, R.S. 1986. Pers. comm. Bureau of Land Mgmt., Kingman Res.
Area, Kingman, AZ.
References - 2