Karyotypes of the long-tailed vole ( Microtus longicaudus ) in isolated mountain ranges of the American Southwest

The long-tailed vole ( Microtus longicaudus ) exhibits karyotypic variation in western North America. In the American Southwest, the species has a disjunct, relict distribution. However, karyotypes obtained from 20 specimens in 5 isolated mountain ranges (White Mountains, Arizona; Mount Taylor and the Sangre de Cristo, Jemez, and Mogollon mountains, New Mexico) exhibited no variation. These and previously reported karyotypes from the region had a diploid number (2n) of 56 and fundamental number (FN) of 84, which is the most commonly reported karyotype for the species.     

Diversification within the Mexican vole ( Microtus mexicanus ) and the role of post-Pleistocene climate change

Normal 0 false false false MicrosoftInternetExplorer4 st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} To examine the partitioning of genetic variation within the Mexican vole ( Microtus mexicanus ), we analyzed variation within the cytochrome b (cyt b, ca. 953 bp) from 44 samples of the Mexican vole from the mountains of the southwestern United States and Mexico. Phylogeographic analyses demonstrated strong support for a western clade and an eastern clade, corresponding to the Sierra Madre Occidental and mountains of the southwestern United States (western clade) and the Sierra Madre Oriental and the Sierra Madre del Sur (eastern clade). Levels of genetic distinctiveness among vole populations in Mexico and the southwestern United States support recognition of the Mogollon vole ( Microtus mogollonensis ). Estimates of lineage divergence suggested an older divergence for populations in Mexico and a more recent divergence for the presumptive M. mogollonensis. Ecological analyses demonstrated a distinct climate niche between vole lineages in the Southwest and Mexico, which indicated the possible role of environmental variation in diversification of the Mexican vole. A similar pattern of climatic separation was also demonstrated between clades of the codistributed taxa Sigmodon hispidus, Neotoma mexicana, and Peromyscus truei, suggesting a broader role for climatic variation in the origin and maintenance of the region’s biodiversity. Para examinar la distribución de la variación genética en el metorito mexicano, analizamos la variación en el citocromo b (cyt b, c. 953 pb ) en 44 muestras del metorito mexicano de las montañas de México y del suroeste de Estados Unidos. Los análisis filogeográficos demostraron fuerte apoyo para un clado occidental y un clado oriental, correspondientes a la Sierra Madre Occidental y las montañas del suroeste de Estados Unidos (oeste) y la Sierra Madre Oriental y la Sierra Madre del Sur (este). Los niveles de diferencia genética entre las poblaciones de metoritos en México y las del sur de Estados Unidos apoyan el reconocimiento del metorito Mogollon ( Microtus mogollonensis ) como especie. Las estimaciones de divergencia entre linajes indican una divergencia más remota para las poblaciones en México y una más reciente para el presunto M. mogollonensis. Los análisis ecológicos demuestran nichos climáticos distintos entre los linajes de metorito en el suroeste de Estados Unidos y en México, lo cual indica el posible papel de la variación ambiental en la diversificación del metorito mexicano. Un patrón similar de separación climática fue también demostrado entre clados de los taxones codistribuidos: Sigmodon hispidus, Neotoma mexicana y Peromysus truei, sugiriendo que la variación climática tiene un mayor papel en el origen y el mantenimiento de la biodiversidad de la región.     

Fleas (Siphonaptera) in nests of boles ( Microtus spp.) in montane habitats of three regions of Utah

As a parallel study of a survey of fleas of trapped small mammals in montane southern Utah, we removed 77 adult fleas from 12 of 13 nests of voles ( Microtus longicaudus, M. montanus and M. richardsoni ) collected from montane meadows in the Abajo and La Sal Mountains, the Markagunt Plateau and Pine Valley Mountains, and the Uinta Mountains, May 1991-July 2002. Six species and subspecies of fleas parasitic on Microtus spp. were found, 1-3 species in each nest. Three specimens of the ubiquitous deer mouse ( Peromyscus spp.) flea Aetheca wagneri (Baker) were also found. We collected the following 7 taxa from the locations indicated: Catallagia decipiens Rothschild in 5 nests: Abajo and Pine Valley Mountains and Markagunt Plateau; Hystrichopsylla dippiei truncata Holland in 2 nests: La Sal and Uinta Mountains; H. occidentalis sylvaticus Campos & Stark in 5 nests: Pine Valley Mountains; Peromyscopsylla selenis (Rothschild) in 1 nest: Markagunt Plateau; A. wagneri in 2 nests: Abajo and Pine Valley Mountains; Megabothris abantis (Rothschild) in 5 nests: Abajo and Uinta Mountains and Markagunt Plateau; Malaraeus telchinus (Rothschild) in 2 nests: Abajo and Pine Valley Mountains. One preserved larva was identified as Hystrichopsylla prob. occidentalis sylvaticus , and 2 dead larvae, the only specimens found in nest 13, were identified as probably the same. Kane County is a new record for C. decipiens and P. selenis ; Kane and Summit Counties are new for M. abantis . Nest surveys can generally supplement rather than replace trapped-host surveys. Their main value is in population studies. They are also a source of larvae for morphology and taxonomy research.     

Hip glands in a natural population of montane voles ( Microtus montanus )

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus   was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.     

High levels of gene flow in the California vole ( Microtus californicus ) are consistent across spatial scales

Gene flow links the genetic and demographic structures of species. Despite the fact that similar genetic and demographic patterns shape both local population structure and regional phylogeography, the 2 levels of population connectivity are rarely studied simultaneously. Here, we studied gene flow in the California vole ( Microtus californicus ), a small-bodied rodent with limited vagility but high local abundance. Within a 4.86-km 2 preserve in central California, genetic diversity in 6 microsatellites was high, and Bayesian methods indicated a single genetic cluster. However, individual-based genetic analysis detected a clear signal for isolation-by-distance (IBD) and fine-scale population structure. Mitochondrial cytochrome b sequencing revealed 11 unique haplotypes from the one local area where we sequenced 62 individuals. Phylogeographic analysis of these individuals combined with those sampled from the northern geographic range of the species (the range of the species spans western North America from southern Oregon to northern Mexico and is centered geographically within the state of California) again indicated a lack of structure but a signal for IBD. Patterns of gene flow thus are consistent across spatial scales: while dispersal of the California vole is limited across geographic distance, there is nonetheless considerable movement across the landscape. We conclude that in this species, high local population abundances overcome the potential genetic and demographic effects of limited dispersal.     

Post-pleistocene dispersal in the Mexican vole ( Microtus mexicanus ): an example of an apparent trend in the distribution of southwestern mammals

The present distribution of the Mexican vole ( Microtus mexicanus ) is not entirely the product of post-Pleistocene forest fragmentation and extinction; recent dispersal also is indicated. Literature records further suggest that this phenomenon may reflect a general pattern of northward range expansion in many southwestern mammal species.     

The systematics of Microtus (Terricola) savii group: an odonthometrical perspective (Mammalia,Rodentia, Cricetidae)

ABSTRACT

The morphology of the first lower molar of Microtus savii group (M. brachycercus, M. nebrodensis, M. savii) is complex and highly variable. A morphometrical analysis done by grouping the samples into large geographical sets reveals the differentiation between northern, central and southern populations. The specific status of M. nebrodensis is confirmed while it is not possible to separate M. brachycercus. The subspecies M. savii tolfetanus and M. brachycercus niethammericus are, respectively, not well and moderate distinguished from the other populations. Finally, the distinction of M. savii group from other species of European voles is also confirmed.     

Horizontal and vertical diameter of burrows of five small mammal species in southeastern Idaho

Burrow diameters of five small mammal species, Townsend's ground squirrel ( Spermophilus townsendii ), Wyoming ground squirrel ( S. elegans ), Ord's kangaroo rat ( Dipodomys ordii ), montane vole ( Microtus montanus ), and deer mouse ( Peromyscus maniculatus ), were examined. Burrow cross sections were noncircular for all species with horizontal diameters 1.2-1.6 times wider than vertical diameters. Montane vole and deer mouse burrows were the smallest diameter, burrows of Wyoming and Townsend's ground squirrels were the largest, and kangaroo rat burrows were intermediate. Soil bulk density and texture significantly affected burrow diameters of montane voles and deer mice but not the other three species.     

Movements by small mammals on a radioactive waste disposal area in southeastern Idaho

Average linear movement by populations of Dipodomys ordii, Microtus montanus, Perognathus parvus, and Peromyscus maniculatus   was investigated over a 15-month period by live trapping on a low-level, radioactive waste disposal area in Idaho. No significant differences in movement among habitats were observed seasonally, excepting M. montanus in spring. Average linear movements within habitats ranged from 20 to 70 m for all species, but some patterns varied seasonally and among age classes for individual species. Although predation on contaminated small mammals from the disposal area is a vector of radionuclide transport, local movements by these rodents do not appear to be of sufficient magnitude to contribute significantly to redistribution of radioactive particles.     

Barn owl diet includes mammal species new to the island fauna of the Great Salt Lake

An investigation of the diet of the Common Barn-owl ( Tyto alba ) on Antelope Island, Great Salt Lake, Utah, yielded four mammal species not previously known to occur on any island in the Great Salt Lake ( Microtus pennsylvanicus, M. montanus, Ondatra zibethicus , and a Sorex sp.). Two other species, known from other islands, were added to the list of fauna of Antelope Island ( Perognathus parvus and Reithrodontomys megalotis ). The barn owl diet on Antelope Island was remarkably like that of barn owls feeding in farmlands adjacent to the Great Salt Lake despite major vegetational differences.     

Mitochondrial DNA genetic variation and phylogeography of the recently described vole species Proedromys liangshanensis Liu,Sun, Zeng and Zhao, 2007 (Rodentia: Arvicolinae)

A vole species, Proedromys liangshanensis Liu, Sun, Zeng and Zhao, 2007 Liu, SY, Sun, ZY, Zeng, ZY and Zhao, EM. 2007. A new vole (Cricetidae: Arvicolinae: proedromys) from the Liangshan Mountains of Sichuan province. China. J Mammal., 88(5): 1170–1178.  [Google Scholar] (Rodentia: Arvicolinae), which is endemic to the Liangshan Mountains, Sichuan, China, was reported in 2007. The species is restricted to a narrow range because of its weak dispersal ability and habitat specificity, and only lives in fir and spruce forests with abundant grass. In this study, the genetic diversity and phylogeographical structure of 42 P. liangshanensis were examined based on analysis of a partial mitochondrial DNA control region. The results revealed low genetic diversity in the P. liangshanensis populations. Twelve nucleotide haplotypes were defined in the 42 collected individuals, and were divided into two major phylogenetic clades, which were obviously related to geographic pattern. Estimates of gene flow (Nm?=?0.09) also revealed a genetic divergence between the Jinyang and Meigu populations. Species-specific traits, habitat specificity and geographic events contributed to the genetic divergence of the new vole. ?These authors contributed equally to this work.      

Terrestrial vertebrates of the Mono Lake islands, California

We compared vertebrate populations between the two major islands (paoha and Negit) in Mono Lake, California and the adjacent mainland to further elucidate the mechanisms underlying island colonization. Deer mice ( Peromyscus maniculatus ) and montane voles ( Microtus montanus ) were captured on Paoha, but only deer mice were captured on Negit. In contrast, eight species of rodents were captured on the mainland. Overall rodent abundance on Paoha and the mainland was similar, but on Negit it was about three times greater than on Paoha or the mainland. Adult deer mice from Paoha were significantly ( P Canis latrans ) and one or two species of lagomorphs were observed on the islands and the mainland. No amphibians or reptiles were found on the islands; both occurred in low numbers on the mainland. Rafting and human transport are probable means of colonization for mice and voles. The occurrence of coyotes on the islands may have modified historic predator-prey relationships, and thus the population of rodents and lagomorphs.     

The sagebrush vole flea, Megabothris clantoni princei, in western Utah, with comments on the distribution of Megabothris in the Bonneville Basin

The sagebrush vole flea ( Megabothris clantoni princei Hubbard) is reported from Utah for the first time, based on collections made in Tooele County. Distribution of the flea Megabothris abantis in the Bonneville Basin is limited to the Oquirrh Mountains, where its presence appears to be determined by the occurrence of the western jumping mouse.     

Effects of soil structure on burrow characteristics of five small mammal species

Burrows of small mammals can impact a variety of soil processes including organic turnover, aeration, and mineralization rates. The structure of burrows, depth, length, and complexity can influence the extent of the impact burrows have on soil processes. Soil properties, in turn, are thought to affect burrow structure. To increase our understanding of burrow-soil dynamics, we compared maximum depth, total volume, total length, volume:length ratio, and complexity of burrows of five small mammal species with bulk density of soil texture in multiple regression analyses. Burrows of Wyoming ground squirrels ( Spermophilus elegans ) were deeper, longer, and more complex as percentage of silt and clay increased and percentage of sand and bulk density decreased. Average maximum depth of montane vole ( Microtus montanus ) burrows increased as soils became sandier. Length and volume of deer mice ( Peromyscus maniculatus ) burrows increased with increases in bulk density and percentage of clay. Volume, length, and complexity of kangaroo rat ( Dipodomys ordii ) burrows were greater in soils with higher amounts of clay and silt. Townsend's ground squirrel ( Spermophilus townsendii ) burrows did not appear to be affected by the soil properties measured.     

Genetic variation of woodrats ( Neotoma cinerea ) and deer mice ( Peromyscus maniculatus ) on montane habitat islands in the Great Basin

Seventeen loci were examined for polymorphism in four populations of Neotoma cinerea and Peromyscus maniculatus on isolated mountain ranges in the Great Basin, one population of each in the Sierra Nevada, and one of each in the Rocky Mountains. All Peromyscus populations had higher levels of heterozygosity than syntopic Neotoma populations.     

Conservation, status, and life history of the endangered White River spinedace, Lepidomeda albivallis (Cyprinidae)

Lepidomeda albivallis (White River spinedace), a fish species endemic to the White River, Nevada, appeared headed toward extinction. In 1991 only 1 population remained, and it comprised fewer than 50 individuals in a 70-m stream reach. We monitored population recruitment and distribution and studied life history and habitat use from 1993 through 1998. We determined that L. albivallis was not reproducing and was continuing to decline, and as an emergency measure we relocated the population (14 in spring 1995 and 6 in spring 1996) downstream 200 m to a secure habitat that we judged more favorable for reproduction. The relocated population reproduced, and by September 1998 it had increased to 396 individuals that inhabited more than 1 km of stream including both pond and stream habitats. In streams they oriented near the bottom but frequently moved up in the water column to strike at drift items. Gut analysis of museum specimens indicated L. albivallis is omnivorous but feeds primarily upon aquatic invertebrates. Conservation of L. albivallis will require reestablishing additional populations within its former range.     

Geographical review of the historical and current status of Ospreys ( Pandion haliaetus ) in Utah

A small numbers of Ospreys ( Pandion haliaetus ) are known to have nested historically in Utah. A precise baseline figure is unavailable, but the 19th-century Osprey population in Utah probably consisted of at least 15 breeding pairs scattered in 4 geographic regions. Human persecution is believed to have caused the abandonment of nesting territories along the Wasatch Front and in the western Uinta Mountains by 1900 and 1960, respectively. Osprey populations in the southern plateaus and Green River areas, however, began increasing in the late 1970s. Several recent nesting attempts and numerous summer sightings at nontraditional and abandoned historical sites in Utah suggest the Osprey is also expanding its range in Utah. High productivity for local pairs and long-range dispersal from more northerly Osprey populations are discussed as sources for the current surge in Utah's Osprey population, which now consists of approximately 35 breeding pairs.     

Biogeographic and taxonomic relationships among the mountain snails (Gastropoda: Oreohelicidae) of the central Great Basin

Described here are 4 species of mountain snails, Oreohelix , isolated on mountains in the central Great Basin of Nevada and Utah since the end of the Pleistocene. Forty-three mountains were searched during an 18-year period, resulting in 24 mountains found with no oreohelicids present. One population, Oreohelix loisae (19 mm to 23 mm in shell diameter), is described here as a new species related to, but geographically isolated from, the species Oreohelix nevadensis (17 mm to 22 mm diameter). Oreohelix loisae is present only in the Goshute Mountains while O. nevadensis is represented in 3 geographically adjacent ranges in the central Great Basin. These 2 species are possibly related to the Oreohelix haydeni group from the northern Wasatch Range. The subspecies Oreohelix strigosa depressa (15 mm to 21 mm diameter) is present on 11 ranges from western Utah west to east central Nevada. This subspecies is closely related to populations found today in the northern Wasatch Mountains of Utah. The smallest species in diameter (8 mm to 14 mm), Oreohelix hemphilli , is centered in the central Great Basin and found on 16 ranges often in sympatry with 1 or 2 of the larger conspecifics. Both qualitative and quantitative information on shell characters and soft anatomy is provided here for these 4 species. Shell characters, soft anatomy, geographical isolation, and statistical analysis suggest that 4 distinct species inhabit the central Great Basin today. Xeric and calciphilic species include O. hemphilli and O. loisae , while O. strigosa and O. nevadensis typically are associated with permanent water and both metamorphic and limestone mountains.     

Species richness and California voles in an annual and a perennial grassland

Populations of a common burrowing rodent, Microtus californicus (the California vole), thrive in ungrazed or lightly grazed grasslands in coastal California. Two sites ungrazed by livestock, one dominated by native perennial grasses and another dominated by invasive annuals, were evaluated over 2 consecutive years for the relationship between plant species richness and location of M. californicus burrow entrances (burrows). Plant species and burrows were sampled as present or absent in contiguous 1-m 2 quadrats on a 100-m 2 grid. Quadrats with burrows averaged significantly more plant species than quadrats without them (11.3 vs. 9.9 species, P < 0.001). Burrows found in 1996 were not correlated with species richness in 1995, suggesting that voles affect richness rather than seek it out. Vole burrow locations showed significant clumping on the annual site and trended toward clumping on the perennial site in both 1995 and 1996. Because voles seem to create a clumped pattern with their burrow entrances, the associated increase in plant species richness may have a strong effect on the overall structure of the plant community. A quantitative comparison of the 2 sites showed that the plant matrix of the perennial site contained flora of the annual site. This similarity in plant species composition may allow for similar treatment of our 2 types of sites and potentially other California grasslands. Undetected increases in vole populations with livestock grazing reduction may account for the erratic results from grasslands management research and the inconsistent success of derived management practices.     

Status of Descurainia torulosa (Brassicaceae)

Descurainia torulosa was established in 1983 based on material collected in northwestern Wyoming. The species is now known from 2 disjunct populations in southwestern Wyoming, and recent collections have expanded the known distribution within the northern portion of its range. The north-south disjunct distribution and apparent habitat differences have stimulated questions concerning the degree of relatedness between the disjunct elements to the point that the southern populations have been suggested to be a distinct taxon. Recognition of D. torulosa as a distinct species has also been questioned. This paper is based on field examination of D. torulosa populations, study of all known D. torulosa herbarium specimens, and analysis of nucleotide sequence from the internal transcribed spacer regions 1 and 2 of nuclear ribosomal DNA (ITS-1 & 2) from population exemplars. Cladistic analysis of the sequence data support our conclusion, based on morphological analysis. Northern and southern populations of D. torulosa are conspecific. Western North American Descurainia is in need of modern, critical taxonomic revision.