Genetically effective and adult population sizes in the Apache silverspot butterfly, Speyeria nokomis apacheana (Lepidoptera: Mynphalidae)

Genetically effective and adult population sizes of the Apache silverspot butterfly ( Speyeria nokomiis apacheana ) from the Great Basin of North America were tracked from 1991 to 1997. Speyeria nokomis inhabits mesic habitats in the Great Basin, and its recent declines in abundance have raised concerns about its future persistence. Adult population size estimates determined from mark-recapture methods ranged from 100 to 1900 individuals from 1993 through 1997. Genetically effective population sizes based on temporal changes in allozyme frequencies ranged from less tha 1 individual to 20 individuals between 1991 and 1995. Despite these small annual estimates, it is likely that gene flow resulted in overestimation of genetically effective population sizes. These reusuts, combined with observations in the field, suggest that suitable but vacan habitat patches be maintained for potential recolonization by S. n. apacheana.     

Genetic variation and population structure in the cliff chipmunk, Eutamias dorsalis , in the Great Basin of western Utah

Allelic variation at 21 of 39 electrophoretically resolved enzyme loci was used to examine patterns of geographic differentiation and population structure in six allopatric samples of Eutamias dorsalis . Coefficients of genetic similarity for paired combinations of E. dorsalis samples ranged from 0.955 to 0.975, except for one population that was 0.900. Conservative genic divergence among five populations is proposed to be the result of relatively recent isolation events. High positive F 18 values and chi– square analyses confirm a significant excess of homozygotes at several loci at the five localities for which sample sizes were statistically adequate. This may be partly attributable to inbreeding, a Wahlund effect, linkage disequilibrium, posttranslational modification, or some combination of these; but at present some of these alternatives cannot be excluded in favor of a single explanation. Some samples were collected across altitudinal gradients of over 800 m, suggesting that a Wahlund effect may be the most likely explanation for low levels of heterozygosity in these populations.     

Montane insular butterfly biogeography: fauna of Ball Mountain, Siskiyou County, California

Ball Mountain is an isolated, mostly heavily forested peak reaching the subalpine zone (2,330 m) in eastern Siskiyou County north of Mt. Shasta, California. It supports a rich fauna of at least 68 butterfly species showing affinities to the faunas of the Trinity Alps and Eddies, the Warners, and the Cascades. Rare or endemic entities include Speyeria monnonia, Lycaena heteronea gravenotata , and melanic forms of Speyeria atlantis and Agriades ";glandon."; Several zones of intergradation or hybridization impinge on the fauna as well.     

Effects of islanding on the genetics of Niviventer confucianus (Mamalia: Rodentia: Muridae) populations in the Thousand Island Lake region

The impact of islanding on the genetics of the dominant species, Niviventer confucianus, was analysed using 13 microsatellite markers. All 16 populations are of high genetic diversity with a total of 134 alleles. The average number of effective alleles (Ne) is 6; the average expected heterozygosity (H_E) and polymorphic information content (PIC) are 0.823 and 0.763, respectively. Landscape fragmentation might contribute to weak genetic differentiation among 13 island populations. Values of F_ST simulated by Structure 2.3.4 implied that the 16 populations could be assigned into three clusters, from which we postulated the possible dispersion history. Pairwise F_ST tests showed that genetic differences mainly occurred between small island populations and others. Currently, habitat area appears to be the main factor affecting the genetics of Niviventer confucianus, and not the distances between islands. Hence we suggest that more attention should be paid to habitat area in the future.     

Isozymes of an autopolyploid shrub, Atriplex canescens (Chenopodiaceae)

Diploid, tetraploid, and hexaploid populations of Atriplex canescens ( x =9) were examined for 18 isozyme systems. Of 24 interpretable loci, only one locus (Per 1 ) was polymorphic. Another locus (Per 2 ) showed a dosage effect. Genetic distance values, D, ranged from near 0 to 0.05, which are in the normal range for local species races. Results from clonal ramets gave identical results. The data and analyses support an essentially autopolyploid origin for the polyploid populations examined.     

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.     

Morphological and genetic variation among populations of the rare Kachina daisy ( Erigeron kachinensis ) from southeastern Utah

Erigeron kachinensis , the Kachina daisy, is a rare species restricted to canyons in southeastern Utah. The species is known to exhibit low fecundity due to low percent fertilization of ovules and high percent abortion of fertilized ovules. Previous reproductive studies suggest that low fecundity is a consequence of small population size and inbreeding depression. This study examines genetic diversity within and among populations of E. kachinensis in Natural Bridges National Monument using enzyme electrophoresis. Field populations are found to have significantly different morphologies. However, morphological differences were less pronounced among populations grown in the greenhouse. The Kachina daisy exhibits levels of genetic variability in its populations similar to that of other outcrossed species. Genetic diversity statistics demonstrate that only 22.8% of genetic variation is distributed among populations. Genetic distance could not be correlated with geographic distance. Most of the populations showed significant deviation of fixation indices from zero for multiple loci. Observation of genotype frequencies demonstrates that populations are fixing on different genotypes and may be experiencing initial stages of genetic drift. Mean observed heterozygosity was 0.166 and was found to increase with increasing size and/or age in populations.     

Naturalization of plains cottonwood ( Populus deltoides subsp. monilifera ) along river drainages west of the Rocky Mountains

Historic botanical surveys documented that the natural distribution of the plains cottonwood ( Populus deltoides subsp. monilifera ) was limited to semiarid drainages east of the Rocky Mountains. Recently, a number of isolated populations of plains cottonwood have been found along the Kootenai, lower Snake, and Columbia Rivers and their tributaries. We used isozyme analysis to assess the genetic structure of these Pacific Northwest (PNW) populations in relation to native cottonwood populations east of the Rocky Mountains. These genetic data along with field surveys (dbh, age estimates) and cadastral field survey notes (mid-1800s) were used to understand the origin of these disjunct populations (i.e., relictual natives versus naturalized introductions). Genetic analyses revealed high levels of genetic diversity within and among PNW populations as well as hybridization with black cottonwood ( P. trichocarpa ). The observed range of genetic variation for PNW populations was similar to that of native cottonwood populations. Collectively, these data confirm that these scattered populations are plains cottonwood ( Populus deltoides subsp. monilifera ). Age estimates of the largest individuals found within study populations ranged from 27 to 51 years. Cadastral field surveys also noted the absence of woody vegetation along the lower Snake and Columbia Rivers. Considered together, the data suggest that these populations are of recent origin. The high levels of observed genetic variation are consistent with the reproductive biology of Populus spp. (i.e., obligate outcrossing and widespread dispersal of pollen and seed by wind and water) and a recurrent introduction of plains cottonwood throughout the study area.     

Biochemical differentiation in the Idaho ground squirrel, Spermophilus brunneus (Rodenta: Scuridae)

Spermophilus brunneus is restricted to a 90 × 125-km area of west central Idaho, with two distinct (northern and southern) groups of populations within this limited range. Morphological differences in pelage length and coloration, external and cranial measurements, and bacula suggest that these groups are either very distinct subspecies or species. We used starch-gel electrophoresis to estimate the amount of genetic differentiation accompanying these morphological differences by assaying genetic variation at 31 loci in the two geographic groups. Fifteen loci were polymorphic (13 in the northern group, 12 in the southern), and mean heterozygosity (H) was high (12.3% northern and 10.8% southern). Nei's genetic distance (0.057) is in the range usually associated with subspecific differences. However, Jaccard's association coefficient (0.893) is about the same as that found between several ground squirrel taxa currently recognized as species. The high levels of heterozygosity suggest that S. brunneus is a neoendemic rather than a paleoendemic species.     

Denning habitat and diet of the swift fox in western South Dakota

Swift fox ( Vulpes velox ) were investigated in western South Dakota to determine food habits and denning site characteristics. Over a three-year period food habits consisted of mammals (49%), followed by insects (27%), plants (13%), and birds (6%). Dens were located near hilltops within two habitat types, shortgrass and midgrass rairie; each type is characterized by differing plant species. Soil type was not a selective factor for den sites of swift fox. Management considerations for enhancing swift fox populations are presented.     

Current status of cutthroat trout subspecies in the western Bonneville Basin

Recent discoveries of native cutthroat trout populations in desert mountain ranges on the western fringe of the Bonneville Basin have prompted intensified management efforts by state and federal agencies. Analysis of Snake Valley cutthroat specimens in Trout Creek, Deep Creek Mountain Range, Utah, indicate this is a pure strain of the trout which once inhabited Pleistocene Lake Bonneville and which was thought to be extinct in Utah. The Snake Valley cutthroat is similar to Salmo clarki utah of the eastern Bonneville Basin; however, electrophoretic and morphomeristic analysis show unique genetic differences brought about by long - term isolation (8,000 years) from the remainder of the Bonneville Basin cutthroat. This cutthroat is a common ancestor to several other limited cutthroat populations within the basin in Nevada. In May 1977 the BLM withdrew from mineral entry about 27,000 acres within the Deep Creek Mountains for protection of this salmonid cutthroat and other unique resources on the range. Results of 1977 stream surveys on the Pilot Peak Mountain Range, Utah, indicate the presence of the threatened Lahontan cutthroat, Salmo clarki henshawi, in one isolated stream.     

Comparison of Gila topminnow and western mosquitofish as biological control agents of mosquitoes

I compared acute tolerance of Gila topminnow, Poeciliopsis occidentalis , and western mosquitofish, Gambusia affinis , to ammonia and high water temperature and also compared diet, food selectivity, and impact on invertebrate populations to evaluate the potential for each species to effectively control mosquitoes (Culicidae) in wetland habitats. Critical thermal maxima differed among species, sexes, and lifestages, but these differences were likely not biologically significant due to their small magnitude and the ability of wild populations of both species to adapt to high temperatures. In 24-hour tests, G. affinis displayed about twice the ammonia tolerance as did P. occidentalis . However, longterm survival in habitats with high ammonia concentrations is questionable, thus reducing the perceived benefit of using G. affinis for mosquito abatement in these habitats. Diet overlap was significant between sexes within species but was not significant between species. However, both species exhibited significant dietary selection for mosquito larvae and pupae under experimental conditions. Shared dietary preference for mosquito larvae and pupae, in addition to similarity in temperature tolerance between species, suggests that P. occidentalis , a native and historically widespread species, can be used in place of nonnative G. affinis for mosquito control. There is no evidence to suggest that nonnative G. affinis is better suited for mosquito abatement, and since G. affinis is replacing P. occidentalis throughout the native species' former range, it should no longer be introduced into the Gila River basin for mosquito control. However, managers who would use P. occidentalis for mosquito abatement must take care not to interfere with conservation efforts by disrupting the genetic structure of natural populations of P. occidentalis .     

Non-invasive genetic study and population monitoring of the brown bear (Ursus arctos) (Mammalia: Ursidae) in Kastoria region – Greece

The brown bear (Ursus arctos) in Greece is considered endangered but little is known about the genetic status and the exact size of local populations. Non-invasive genetic sampling was used in this study to investigate the genetic diversity and genetic structure of the brown bear population in the Kastoria region (northwest Macedonia, Greece) and to estimate its population size. Estimation of demographic parameters was based on innovative, well-evaluated methods that can provide estimates from a single sampling session. DNA was extracted from hairs, scat and blood samples and subsequent amplification of 10 microsatellite loci allowed the identification of a minimum number of 75 living bears in the study area while the mark–recapture-based analysis resulted in a point estimation of 219 individuals. Relatively high diversity values, lack of heterozygosity deficiency as well as estimated effective population size, support the Kastoria bear population having good conservation status.     

Genetic differentiation and gene flow of Porcellionides pruinosus (Crustacea: Isopoda: Oniscidea) in Tunisia

Iso-enzymatic polymorphism analysis was carried out on Tunisian populations of Porcellionides pruinosus to clarify their confused taxonomic status, previously revealed by reproductive and morphological approaches. Seventeen allozyme loci were studied, using horizontal starch gel electrophoresis, in 230 adult specimens belonging to nine populations of P. pruinosus located in north, central and south Tunisia, to assess the levels of their intra-genetic and inter-genetic diversity, and to analyse their genetic structure. Our results indicate a low genetic variability with a polymorphism ratio ranging from 29.4% in Tabarka to 47.1% in the Garat Nâam and Raccada populations, and the mean number of alleles per locus was estimated at 1.51 ± 0.15. The direct-count of heterozygosity ranged between 8.1% and 15%. Substantial estimates of demic structuring were found at the total population (F_ST = 0.198), with a generalized and significant heterozygote deficiency detected in every population (with a mean value for all populations of F_IS = 0.372). Genetic distances between the studied populations were low, indicating that they belong to the same species. Nevertheless, the genetic analyses showed the divergence of the population of Tabarka from all the other studied populations, with the lowest mean gene flow, 0.58, and the highest mean genetic distance, (0.182) obtained also by the morphological and reproductive approaches.     

Allozyme variability, isolation, and dispersal of Eusattus muricatus (Coleoptera: Tenebrionidae) within Silver State Dune Complex, Great Basin, western North America

Genetics of Eusattus muricatus (Coleoptera: Tenebrionidae) populations within Silver State Dune Complex in the northern Great Basin of North America were assayed using allozyme electrophoresis. Hierarchical F -statistics showed no significant population subdivision among 3 valleys comprising Silver State Dune Complex. A regression of estimated pairwise gene flow ( Nm ) against pairwise geographic distance was not significant for populations within these valleys, but it was significant over larger distances. A neighbor-joining phenogram did not represent geographic relationships among populations in the 3 valleys but reflected the past geologic history of these dunes. Pairwise divergence times were low (>7000 yr) for populations within Silver State Dune Complex but were high (>18,000 yr) in outgroups.     

Ecology of Comandra umbellata (Santalaceae) in western Wyoming

Comandra umbellate is the alternate host of a hard pine canker rust disease induced by the fungus Cronartium comandrae . The occurrence and density of C. umbellata were recorded near lodgepole pine stands in the Wind River District, Shoshone National Forest, Wyoming. Comandra populations occurred most often on slopes with southern aspects, particularly southwestern, and on steep slopes; these sites tended to be dry and relatively open. Comandra was also found growing under heavy perennial shrub canopy covers. It was most often associated with sagebrush but was common near other perennial shrubs as well. Overall, C. umbellata appeared to be a poor competitor with dense grass populations. Comandra was found primarily on Abies lasiocarpa/Juniperus communis, Pinusflexilis/ Hesperochloa kingii , and Artemisia tridentata/Festuca idahoensis habitats. No comandra was found in the Abies lasiocarpa/Vaccinium scoporium habitat.     

Records of the northern grasshopper mouse ( Onychomys leucogaster ) in western Iowa

In Iowa, the northern grasshopper mouse ( Onychomys leucogaster ) previously was known only from the northwestern part of the state. Herein, we report records of O. leucogaster from the 1970s and 1980s that extend its distribution into west-central and southwestern Iowa. These records may represent dispersal movements into these parts of Iowa by southward movements from populations in northwestern Iowa or they may represent eastward movements of individuals from Nebraska prior to channelization of the Missouri River.     

Life history variation in recently established populations of western mosquitofish ( Gambusia affinis )

We report life history characteristics for 4 recently established populations of western mosquitofish ( Gambusia affinis ). Mosquitofish from thermally stable habitats, Bonham and Garrett, were characterized by maturity at large sizes, high fat reserves, and large embryos. In contrast, females from a thermally unstable habitat, Wabuska, matured at small sizes and had low fat reserves and small embryos. Females from Parker, a site with no appreciable thermal input, matured at intermediate sizes and had low fat reserves as well as large embryos. These populations shared a common ancestor in 1937; therefore, these results suggest either phenotypic plasticity or rapid evolution.     

Effect of western white pine cone production variability on mountain pine cone beetle population levels

Yearly variation in numbers of cones produced by western white pine was found to affect the population level of the mountain pine cone beetle. In years when cone production is moderate to heavy, beetle populations increase. Increasing beetle populations are ultimately limited by poor cone crops, which increase competition for nutrients and oviposition sites. Variability in western white pine cone production is regarded as the most important factor regulating populations of the mountain pine cone beetle.