Valley Population Research Articles

Inland diatoms from the McMurdo Dry Valleys and James Ross Island, Antarctica

Diatom taxa present in the inland streams and lakes of the McMurdo Dry Valleys and James Ross Island, Antarctica, are presented in this paper. A total of nine taxa are illustrated, with descriptions of four new species ( Luticola austroatlantica sp. nov., Luticola dolia sp. nov., Luticola laeta sp. nov., Muelleria supra sp. nov.). In the perennially ice-covered lakes of the McMurdo Dry Valleys, diatoms are confined to benthic mats within the photic zone. In streams, diatoms are attached to benthic surfaces and within the microbial mat matrix. One species, L. austroatlantica, is found on James Ross Island, of the southern Atlantic archipelago, and the McMurdo Dry Valleys. The McMurdo Dry Valley populations are at the lower range of the size spectrum for the species. Streams flow for 6–10 weeks during the austral summer, when temperatures and solar radiation allow glacial ice to melt. The diatom flora of the region is characterized by species assemblages favored under harsh conditions, with naviculoid taxa as the dominant group and several major diatom groups conspicuously absent.

Clarification of anomalies in the application of a 2La molecular karyotyping method for the malaria vector Anopheles gambiae

BackgroundChromosomal inversions have been considered to be potentially important barriers to gene flow in many groups of animals through their effect on recombination suppression in heterokaryotypic individuals. Inversions can also enhance local adaptation in different groups of organisms and may often represent species-specific differences among closely related taxa. We conducted a study to characterize the 2La inversion karyotypes of An. gambiae sensu stricto mosquitoes sampled from the Kilombero Valley (Tanzania) using a newly designed PCR assay.ResultsWe frequently encountered a (687 bp) fragment which was only present in the Kilombero Valley populations. Laboratory crossing between An. gambiae s.s. from Njage (Tanzania) and Kisumu (Western Kenya) populations resulted in F1 offspring carrying the observed fragment. Karyotype analysis did not indicate differences in 2La region chromosome morphology between individuals carrying the PCR fragments, the 207 bp fragment, or the 687 bp fragement.ConclusionThe observed insertion/deletion polymorphism within the region amplified by the 2La PCR diagnostic test may confound the interpretation of this assay and should be well considered in order to maintain an acceptable level of reliability in studies using this assay to describe the distribution and frequency of the 2La inversion among natural populations of An. gambiae s.s.

Transport and mobility properties of wurtzite InN and GaN

AbstractThe results of an ensemble Monte Carlo model of the electron transport in wurtzite gallium nitride (GaN) and indium nitride (InN) are presented. There is a controversy over the material parameters of InN, therefore the recently reported and the traditionally accepted parameter values for InN are used in simulations and the results are compared. The steady‐state and transient electron transport characteristics are analyzed and the valley populations of electrons are determined as a function of electric field. The low‐field mobility of electrons is also obtained as a function of temperature and over a wide range of carrier concentrations. It is seen that with the recently published material parameters the peak velocity of carriers in InN increases significantly, while the field at which it is attained decreases. The calculated maximum low field mobility at 300 K in InN with the recent material parameters is about 10000 cm2/V s for low carrier concentrations. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Valley susceptibility of interacting electrons and composite fermions

We report magnetotransport measurements of integer and fractional quantum Hall states in an AlAs quantum well where two conduction band valleys are occupied. By monitoring the valley level crossings for these states as a function of applied symmetry-breaking strain, we determine the “valley susceptibility” (the change of valley population with strain) for both electrons and composite Fermions. The data reveal that these valley susceptibilities are significantly enhanced over the band values, reflecting the role of strong interaction. Moreover, the measured valley susceptibilities are quite similar to the values of spin susceptibility, establishing the analogy between the spin and valley degrees of freedom.

Use of RAPD and ITE molecular markers in studying the genetic structure of the Crimean population of T. boeoticum Boiss

The influence of ecological factors on variation of random PCR markers (RAPD and inter-MITE polymorphism (IMP) primers) was evaluated in two wild Triticum boeoticum populations with contrasting climatic conditions in Crimea. The proportion of variation that undergoes natural selection was compared for these two types of molecular markers. The Sapun Mountain and Baidar Valley populations differed significantly in 24.7% of the analyzed loci, with a low Nei distance between these populations (0.0324). The number of significantly different RAPD and IMP markers in the two populations was nearly equal. Testing for evolutionary neutrality showed that 13 loci (17.8%) were influenced by natural selection. The Sapun Mountain population was more dependent on natural selection (ten loci, 13.7%) than the Baidar Valley population (four loci, 5.5%). Eleven out of the 13 loci undergoing selection were amplified with IMP primers.

Stable isotopes and diet at Ancient Kerma, Upper Nubia (Sudan)

Carbon and nitrogen stable isotope values were measured from bone collagen extracted from archaeological Nubian human ( n = 54) and faunal ( n = 61) populations from the site of Kerma, Sudan. Collagen suitable for isotopic analysis was extracted from 22 faunal and 48 human samples from the Eastern cemetery site, dated to the Middle Kerma (c. 2050–1750 BC) and Classic Kerma (c. 1750–1500 BC) periods respectively. The isotopic data indicate that the human dietary regimen included a mix of C 3 and C 4 plant-derived components, with a larger C 4 component than previously reported in archaeological Egyptian Nile Valley populations. Elevated δ 15N values are attributed to consumption of dietary resources from a 15N-enriched terrestrial ecosystem. The faunal isotope data also indicate the consumption of C 3 and C 4 plants. The large range of δ 13C values measured in both the human and faunal samples supports previous work suggesting that a significant portion of the populations buried at Kerma may have originated elsewhere, further confirming the Nile Valley as a major corridor for population movement in the region.

THE PRE-HISPANIC COMMUNITIES OF THE ONAVAS VALLEY

Despite the impressive amount of archaeological research conducted in Sonora in the last few decades, some areas remain little researched. The Middle Río Yaqui region is one such area. Traditionally, this region has been identified as part of the Río Sonora archaeological tradition that embraces the sierra region from near the international border south to northern Sinaloa. No archaeological research has been conducted in the middle of this region to verify this interpretative assumption, however. This essay presents basic data from the Onavas Valley Archaeological Project (OVAP), which was conducted in the Middle Río Yaqui Valley in the summer of 2004 to obtain an initial understanding of an archaeologically poorly researched area and to examine the area’s possible role in interactions with neighboring archaeological areas. The data illustrate that the Onavas Valley population appears to have been more related to the Huatabampo archaeological tradition than to the Río Sonora archaeological tradition.

Genetic evidence for the persistence of the critically endangered Sierra Nevada red fox in California

California is home to both the native state- threatened Sierra Nevada red fox (Vulpes vulpes ne- cator), which historically inhabited high elevations of the Sierra Nevada and Cascade mountains, and to multiple low-elevation red fox populations thought to be of exotic origin. During the past few decades the lowland populations have dramatically expanded their distribution, and possibly moved into the historic range of the native high-elevation fox. To determine whether the native red fox persists in its historic range in Cali- fornia, we compared mitochondrial cytochrome-b haplotypes of the only currently-known high-elevation population (n = 9 individuals) to samples from 3 modern lowland populations (n = 35) and historic (1911-1941) high-elevation (n = 22) and lowland (n = 7) populations. We found no significant popula- tion differentiation among the modern and historic high-elevation populations (average pairwise FST = 0.06), but these populations differed substantially from all modern and historic lowland populations (average pairwise FST = 0.52). Among lowland populations, the historic and modern Sacramento Valley populations were not significantly differentiated from one another (FST = -0.06), but differed significantly from recently founded populations in the San Francisco Bay region and in southern California (average pairwise FST = 0.42). Analysis of molecular variance indicated that 3 population groupings (mountain, Sacramento Valley, and other lowland regions) explained 45% of molecu- lar variance (FCT = 0.45) whereas only 4.5% of the variance was partitioned among populations within these groupings (FSC = 0.08). These findings provide strong evidence that the native Sierra Nevada red fox has persisted in northern California. However, all nine samples from this population had the same haplotype, suggesting that several historic haplotypes may have become lost. Unidentified barriers have apparently prevented gene flow from the Sacramento Valley population to other eastern or southern populations in California. Future studies involving nuclear markers are needed to assess the origin of the Sierra Nevada red fox and to quantify levels of nuclear gene flow.

Genetic diversity of Phyllanthus emblica populations in dry-hot valleys in Yunnan

Genetic diversity of Phyllanthus emblica populations in dry-hot valleys in Yunnan

Genetic Variation of Common Ash (Fraxinus excelsior L.) Populations From Provenance Regions in Southern Germany by Using Nuclear and Chloroplast Microsatellites

Abstract The genetic structure of 14 populations from three ash provenance regions (Fraxinus excelsior L.) in southern Germany (Aid Infodienst, 2003) is described by analysing the variation of four nuclear and five cpDNA microsatellites. The study of the nuclear microsatellites revealed high levels of genetic diversity but low levels of genetic differentiation, suggesting a high degree of gene flow among regions and/or human interference by introducing plant material coming from different provenances. The distributions of the allele frequencies and the genetic structures at these four microsatellite loci did not allow the identification of distinct provenance regions, although “private alleles” were encountered with moderate to low frequencies (above 5 percent). Specifically, the Rhine valley populations (provenance region 81105) and these from the Swabian Jura and Black Forest (provenance region 81107) revealed private alleles at the two microsatellite loci Femsatl4 and Femsatl12. A more distinct differentiation between provenances was found based on the cpDNA markers. Evidence on genetic delineation and characterization of ash provenances is discussed. Based on these results, provenance regions can be genetically characterised but further analysis of ash populations and of reproductive material (seeds or seedlings) would be of great importance for provenance delineation, as well as gene conservation and sustainable management of ash populations.

Valley Susceptibility of an Interacting Two-Dimensional Electron System

We report direct measurements of the valley susceptibility, the change of valley population in response to an applied symmetry-breaking strain, in an AlAs two-dimensional electron system. As the two-dimensional density is reduced, the valley susceptibility dramatically increases relative to its band value, reflecting the system's strong electron-electron interaction. The increase has a remarkable resemblance to the enhancement of the spin susceptibility and establishes the analogy between the spin and valley degrees of freedom.

Movements and Survival of Juvenile Greater Sage-Grouse in Southeastern Idaho

Low recruitment has been suggested as a primary factor contributing to declines in greater sage-grouse (Centrocercus urophasianus) populations. We evaluated movements and survival of 58 radiomarked juvenile greater sage-grouse from 1 September (≥10 weeks of age) to 29 March (≥40 weeks of age) during 1997–1998 and 1998–1999 in lowland and mountain valley study areas in southeastern Idaho, USA. Juvenile sage-grouse captured in the mountain valley area moved an average of 2.2 km (20%) farther (x = 13.0 km, SE = 1.2 km) from autumn to winter ranges than juvenile grouse captured in the lowland area (x = 10.8 km, SE = 1.2 km). Ten of 11 deaths occurred from September to December. Fifty percent of deaths in the lowland population were attributable to human-related mortality including power-line collisions and legal harvest, while 33% and 17% of deaths were attributable to mammalian predators and unknown cause, respectively. All deaths in the mountain valley population were attributed to avian or mammalian predators. Survival was relatively high for birds from both populations, but was higher across years in the lowland (Ŝ = 0.86, SE = 0.06, n = 43) than in the mountain valley population (Ŝ = 0.64, SE = 0.13, n = 14). In our study juvenile sage-grouse that moved farther distances to seasonal ranges experienced lower survival than juveniles from a more sedentary population. Moreover, high juvenile survival in our study suggests that if low recruitment occurs in sage-grouse populations it may be due to other factors, especially poor nesting success or low early chick survival.

Genetic analysis reveals two distinct Sacramento splittail (Pogonichthys macrolepidotus) populations

The Sacramento splittail is an endemic cyprinid fish of the San Francisco estuary and its tributaries, which is a highly manipulated, constantly changing ecosystem. Splittail is the only extant member of its genus and is listed as a federal and California Species of Special Concern due to uncertainties regarding long-term abundance trends. Determining population structure for splittail is important because unique populations may contain different adaptive genetic variation, which can allow one population to persist through future environmental or demographic stochasticity while others become extirpated. To assess splittail population structure, 13 microsatellite markers were used to genotype 489 young-of-year splittail from five major rivers draining into the estuary: Cosumnes, Napa, Petaluma, Sacramento, and San Joaquin Rivers. Two genetically distinct populations were found to exist within our study region; one largely comprised of splittail collected from the Petaluma and Napa Rivers and the second comprised of splittail collected from tributaries in Californiaȁ9s Central Valley: Cosumnes, Sacramento, and San Joaquin Rivers. These results were replicated in two consecutive years with both distance and model-based algorithms. The genetic distinction between these two populations appears correlated with salinity differences between migratory regions and spawning grounds. Splittail from the Petaluma River exhibited a significantly higher degree of differentiation from the Central Valley population than did Napa River splittail. Our results suggest on-going monitoring programs are probably highly biased towards sampling splittail from the Central Valley population. Understanding population dynamics of splittail could be improved if monitoring programs were expanded to include all splittail populations.

A new species of the genus Aphanius (Nardo, 1832) (Actinopterygii, Cyprinodontidae) from Algeria

A new species, Aphanius saourensis sp. nov., is described based on morphological and genetic characters. The new species comes from the Saoura Valley in northwestern Algeria. It differs from Aphanius iberus, in which the Saoura Valley populations have been included until now, by a combination of the following characters: 7–8 (9) branched rays in dorsal fin; greater preorbital length (PrOL/ED=0.9–1.3); and a narrower caudal peduncle (CPL/BLD=1.7–2.0). Body pigmentation in live males consists of a profusely mottled blue and silver pattern, without vertical bars. Females lack conspicuous black spots. The new species differs from both of its sister taxa (Aphanius iberus and A. baeticus) at 26 fixed nucleotide positions (molecular autapomorphies) in the cytochrome b gene. Genetic divergence between Aphanius iberus and Aphanius saourensis sp. nov. for the cytochrome b gene is 4.9–5.8 % and between Aphanius baeticus and Aphanius saourensis sp. nov. 6.3– 6.5 %.

Ecological Relocation of the Palaeoendemic Iberotrechus bolivari (Jeannel): from Troglobiont to Epigean (Coleoptera: Carabidae: Trechini)

Abstract The trechine carabid species Iberotrechus bolivari (Jeannel) was thought to be a troglobite confined to the type locality (Cueva del Pis). Discovery of epigeal populations in the Cantabrian valleys of the Pas and Pisuena river basins and in nearby caves have enlarged the geographical range of this species to an additional three caves of the valleys of the Pisuena, Besaya and Ason river. New data on the biology and way of life of the species show that it is markedly hygrophilous, lucifugous and epigeal: habits that enable permit its occasional establishment in the underground environment are confirmed.

Population and genetic status of Primula kisoana var. kisoana, a local endemic of the northern Kanto region, Japan

Abstract Primula kisoana var. kisoana is a clonal distylous herb restricted to the Mount Narukami area of Japan. In recent years, its population has severely declined and no seed set has been observed in the natural habitat. The current status of P. k. var. kisoana was investigated to develop an effective management plan for the species. Only seven local populations, comprising less than 600 ramets, were found. The large distances between compatible pairs of genets suggest that pollen limitation may be a major cause of regeneration failure. Only 10 multilocus genotypes were found for five microsatellite loci, each of which was likely to represent a unique genet. High levels of genetic heterozygosity and no significant deviation from Hardy–Weinberg equilibrium were detected, indicating that random mating has occurred until recently. Microsatellite and chloroplast DNA polymorphism suggest that genetic differentiation has occurred between populations in different valleys. Measures to conserve the species, including the preservation of all local populations and the improvement of seed reproduction, should be applied immediately.

Land and Liberty: Hudson Valley Riots in the Age of Revolution

This study of discontent in the Hudson River valley is intended as a firm corrective to existing scholarship. Thomas J. Humphrey charges earlier historians with limited vision—chron-ologically, geographically, or both—and with insufficient attention to the dialectic between the Revolution and ongoing unrest. He argues that casting a wider evidential net over both space and time (the entire valley from mid-century through the Revolution) will show, first, how insurgents moved from claims of ownership based upon title, practical possession (squatting), or improvement to a more sophisticated combination of the three, “insisting that their labor and occupancy of the land entitled them to own it,” and, second, how disputes in the postrevolutionary period “infused long-standing disputes with Revolutionary rhetoric to forge new definitions of citizenship, property ownership, and civic equality” (p. 10). There is much of interest here. Humphrey provides clear definitions of landlord, freeholder, and leaseholder, and he is especially interesting on why the gap between the first two was so large despite their sharing control over property. His portrayal of the worried improvisation that underlay the appearance of landlord domination, a scrambling that the Revolution only complicated, is strong. He is subtle on the players from Massachusetts and on other aspects of the extramural side of the valley's history. He works hard on why landlords in the southern reaches of the valley generally opted for Loyalism, while their northern counterparts went mostly Patriot. If readers feel unsure about how the same motivation (“Landlords in the southern valley sided with the king in part to preserve their land and power. Landlords in the northern valley joined the Revolution for the same reason,” p. 92) could produce such different results, Humphrey's account assures them that Robert Livingston and his contemporaries were often no less puzzled. When Humphrey concentrates upon the less prominent, less privileged segments of the valley's population, he humanizes discontent by finding individuals—the Wappinger Indian claimant Ninham, the insurgent Josiah Loo-mis. Where the evidence allows he is sensitive to background, revealing a population that is striking in its ethnic diversity. If he is thin on the most historically silent of all groups in the mix, that part of the tenant population that stubbornly did not revolt, did not petition, did not experiment with these and other ways of changing the status quo while often providing landlords with the muscle to maintain their hegemony, it is because those who do not get jailed do not leave much of a record.

Conchometrics, systematics and distribution of Melanopsis (Mollusca: Gastropoda) in the Levant

In this conchometric study, the systematics and distribution of the freshwater gastropod Melanopsis in the Levant are described. Of the ten species found, three are widespread, two have narrow distributions and five are known only from their type locality. Five smooth-shelled species are recognized (buccinoidea, ammonis, dircaena, khabourensis and meiostoma). Within M. buccinoidea, Jordan Valley populations may belong to a separate subspecies. M. ammonis is clearly differentiated from buccinoidea of the nearby Jordan Valley, but less so from buccinoidea of more distant sites; differences between ammonis and meiostoma are significant but not diagnostic. Five species have ribbed shells. Within costata, four subspecies are recognized (in the northern Orontes, upper Jordan, Sea of Galilee, and in southernmost parts of the Levant). Throughout the Levant, M. buccinoidea frequently hybridizes with M. costata and fossil evidence suggests that these species have been hybridizing for the last 1.5 Myr. M. saulcyi differs from M. costata in its narrower shell and shorter, bumpier ribs and frequently hybridizes with M. buccinoidea throughout the Levant. Specimens from Homs differ from those of the Jordan Valley in their higher figurativity index, fewer ribs and lower rib density. M. germaini differs from M. costata in its more numerous ribs, M. pachya in its shorter ribs, and M. infracincta in its bumpy shell in which each rib has huge tubercles, with a pronounced ridge flanking the columella. Our conclusion that there are ten species in the Levant differs from previous studies that suggested only two subspecies of one species (or superspecies). This difference could stem from (1) our use of nonstandard as well as standard conchometrics, (2) a reappraisal of the importance of the shell vs. the radula in intrageneric systematics, and (3) differences of opinion on the subspecies concept. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144, 229−260.

La séquence loessique de Kurtak (Bassin de l'Iéniséi, Sibérie) : un enregistrement de référence pour le stade de Karga (SIM 3)

The loess-palaeosol succession of Kurtak, along the western slope of the Yenisei Valley, is one of the best documented Late Pleistocene sequences in southern Central Siberia. The present paper deals with the Kurtak Pedocomplex and with the Chani Bay Complex preserved on the plateau and in a lateral depression respectively, which correspond to the Karga Stage (MIS 3). For this sequence we obtained a detailed palaeoclimatic succession based on pedological and palynological data recording 14 short interstadial periods. The chronology of this record is well established by ca 100 radiocarbon dates on charcoal and wood remains, ranging from 42,520 to 25,710 BP. Botanical analysis shows a steppe-like vegetation with small tree populations (spruce, pine, birch) in lateral valleys during the colder periods. During the interstadial episodes spruce populations grew denser in the valleys, while scattered spruce, larch and pine trees expanded on the plateau. Therefore, the Kurtak Pedocomplex and Chani Bay Complex provide a unique climatic record for MIS 3, similar to the middle pleniglacial succession of the Dinkel Valley in the Netherlands and to loess-palaeosol records of Eastern and Central Europe. This means that the Siberian record shows a climatic sequence of global significance, and that the environmental conditions during MIS 3 were highly unstable at the Eurasian continent.

A karyological study of swamp and dry valley populations of Siberian fir (Abies sibirica Ledeb.)

The karyological data on populations of Siberian fir (Abies sibirica Ledeb.) growing in lowland swamp and dry valleys are given. The diploid set of both populations included 24 chromosomes (2n = 24). Polykaryogram analysis revealed seven pairs of metacentric and five pairs of submetacentric chromosomes. The revealed differences between the populations included the absolute length of chromosomes, number of nucleolar organizer regions, and number of nucleoli. Changed chromosome numbers (mixoploidy and aneuploidy) as well as chromosomal aberrations were recorded. For the first time, mitosis was studied in this species and anaphase/telophase aberrations were revealed. The population of Siberian fir growing under extreme conditions of lowland swamp featured the widest range of mutations.