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The distribution and abundance of the greater sage-grouse (Centrocercus urophasianus) have declined dramatically, and as a result the species has become the focus of conservation efforts. We conducted a range-wide genetic survey of the species which included 46 populations and over 1000 individuals using both mitochondrial sequence data and data from seven nuclear microsatellites. Nested clade and STRUCTURE analyses revealed that, in general, the greater sage-grouse populations follow an isolation-by-distance model of restricted gene flow. This suggests that movements of the greater sage-grouse are typically among neighbouring populations and not across the species, range. This may have important implications if...
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Accurate assessment of species identity is fundamental for conservation biology. Using molecular markers from the mitochondrial and nuclear genomes, we discovered that many putatively native populations of greenback cutthroat trout (Oncorhynchus clarkii stomias) comprised another subspecies of cutthroat trout, Colorado River cutthroat trout (Oncorhynchus clarkii pleuriticus). The error can be explained by the introduction of Colorado River cutthroat trout throughout the native range of greenback cutthroat trout in the late 19th and early 20th centuries by fish stocking activities. Our results suggest greenback cutthroat trout within its native range is at a higher risk of extinction than ever before despite conservation...
This project used species distribution modeling, population genetics, and geospatial analysis of historical vs. modern vertebrate populations to identify climate change refugia and population connectivity across the Sierra Nevada. It is hypothesized that climate change refugia will increase persistence and stability of populations and, as a result, maintain higher genetic diversity. This work helps managers assess the need to include connectivity and refugia in climate change adaptation strategies. Results help Sierra Nevada land managers allocate limited resources, aid future scenario assessment at landscape scales, and develop a performance measure for assessing resilience.
Categories: Data, Project; Tags: 2011, 2013, CA, California Landscape Conservation Cooperative, Conservation Design, All tags...
The Rio Grande cutthroat trout, Oncorhynchus clarkii virginalis, has declined precipitously over the past century, and currently exhibits a highly fragmented distribution within the Canadian, Pecos and Rio Grande river systems of the western United States. The relationships between populations in the three river drainages, and between O. c. virginalis and the closely related taxa O. c. pleuriticus and O. c. stomias, are not well understood. In order to guide management decisions for the subspecies, we investigated the distribution of variation at 12 microsatellite loci and two regions of the mitochondrial genome. We observed a high level of genetic differentiation between O. c. virginalis populations occupying different...
The presence or absence of heterozygous individuals and overall genetic variation were determined for the invasive exotic annual grass Bromus tectorum from four populations in northern Nevada using seven species-specific polymorphic di-nucleotide microsatellite markers. Allelic polymorphisms were found in all populations, but not at all loci within each population. Mean genetic diversity across loci within populations ranged from 0.009 ± 0.006 to 0.551 ± 0.073, across populations x̄ = 0.234 ± 0.043. Fifteen individuals from the total sample (8.24%) were heterozygous at 1–4 loci. Two populations exhibited no heterozygosity and the remaining two populations had relative heterozygote proportions of 22.5% and...
In the Sonoran Desert of North America, populations of the desert tortoise (Gopherus agassizii) occur in rocky foothills throughout southwestern Arizona and northwestern Mexico. Although tortoise populations appear to be isolated from each other by low desert valleys, individuals occasionally move long distances between populations. Increasingly, these movements are hindered by habitat fragmentation due to anthropogenic landscape changes. We used molecular techniques and radiotelemetry to examine movement patterns of desert tortoises in southern Arizona. We collected blood samples from 170 individuals in nine mountain ranges and analyzed variability in seven microsatellite loci to determine genetic differentiation...
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We utilized nine microsatellite loci and 865 bases from two mtDNA genes to estimate demographic parameters and visualize historic/contemporary connectivity among populations of a sky-island rattlesnake (New Mexico ridge-nosed rattlesnake, Crotalus willardi obscurus). This taxon is listed as threatened under the United States Endangered Species Act (ESA) and is distributed patchily within three borderland mountain ranges [Animas (ANM), Peloncillo (PEL), Sierra San Luis (SSL)] of southeastern Arizona, southwestern New Mexico and north-central M�xico. Molecular data support a hypothesis of northward range expansion from M�xico, with subsequent isolation on sky-islands through vicariant desertification that transformed...
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Single sequence repeat (SSR) and amplified fragment length polymorphic (AFLP) molecular marker genotypes in cheatgrass (Bromus tectorum) were compared to published data on phenotypic variation in seed dormancy, vernalization requirement, and resistance to the pathogen Ustilago bullata. Several features of cheatgrass facilitated this study: it is a recent invader in the western United States, has considerable phenotypic polymorphism, and is an obligate self-pollinator. Forty self-pollinating lines from four populations common to the three phenotypic data sets were analyzed for molecular genetic variation using seven SSR loci and 31 AFLP loci. We examined correlations between distance matrices using the Mantel test...
Gene flow and potential for Sin Nombre virus (SNV) trafficking of the deer mouse (Peromyscus maniculatus) was studied in Delta and Mesa counties of western Colorado (USA). The study areas included Grand Mesa and surrounding grazing and agricultural areas. This area has several natural potential barriers to rodent gene flow, including rivers, cliffs, and mountains. Ten study sites were utilized in a spatially nested design ranging from 0.65-81 km apart; four of these sites were at or near human hantavirus pulmonary syndrome (HPS) case-patient residences. One HPS case occurred on the north side of Grand Mesa in 1993; the other three (two confirmed, one presumptive) occurred on the south side of Grand Mesa between...
Ten polymorphic microsatellite loci (containing tri and tetra-nucleotide repeats) were developed for the Lahontan cutthroat trout (Oncorhynchus clarki henshawi), a subspecies of cutthroat trout listed as threatened under the United States Endangered Species Act. Polymorphism was assessed for 445 individuals from 12 populations representing eight watersheds spread throughout the three Distinct Population Segments defined for this subspecies. All loci were polymorphic (X? = 19, range 7?26 alleles). All loci were in Hardy?Weinberg equilibrium (HWE) except for one locus (OCH 9) in a single population (P < 0.00014 after Bonferroni correction for multiple tests). Published in Molecular Ecology Notes, volume 4, issue 4,...
Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing three questions: (i) do ridges act as barriers...
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Dispersal can strongly influence the demographic and evolutionary trajectory of populations. For many species, little is known about dispersal, despite its importance to conservation. The Greater Sage-Grouse (Centrocercus urophasianus) is a species of conservation concern that ranges across 11 western U.S. states and 2 Canadian provinces. To investigate dispersal patterns among spring breeding congregations, we examined a 21-locus microsatellite DNA dataset of 3,244 Greater Sage-Grouse sampled from 763 leks throughout Idaho, Montana, North Dakota, and South Dakota, USA, across 7 yr. We recaptured ~2% of individuals, documenting 41 instances of breeding dispersal, with 7 dispersal events of .50 km, including 1 of...
Primers for five polymorphic microsatellite loci were developed for the midget faded rattlesnake (Crotalus viridis concolor), a rare subspecies of western rattlesnake (Crotalus viridus) found only in parts of Wyoming, Colorado, and Utah. Five polymorphic microsatellites were isolated, four of which had relatively high levels of diversity (eight to nine alleles). We found only two departures from Hardy?Weinberg equilibrium and they occurred in different loci, so null alleles are likely not a problem. Moreover, we found that no two loci were linked. These loci will be applicable for population genetic analysis and perhaps analysis of paternity and mating systems. Published in Molecular Ecology Notes, volume 5, issue...
The endangered Indiana bat (Myotis sodalis) has declined dramatically and continuing threats have made it necessary to understand population dynamics and life history throughout the year. Specifically, demographic information (e.g., population size, reproductive success, survival) from the summer range where females raise their young in maternity colonies is difficult to estimate precisely using traditional techniques (such as emergence counts). Further, the familial makeup of maternity colonies is unknown. Genetic mark-recapture methods are increasingly being used to estimate demographic parameters in species where traditional techniques are problematic and can also provide insight into relatedness among individuals....
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Bromus tectorum (cheatgrass or downy brome) is an exotic annual weed that is abundant in western USA. We examined variation in six microsatellite loci for 17 populations representing a range of habitats in Utah, Idaho, Nevada and Colorado (USA) and then intensively sampled four representative populations, for a total sample size of approximately 1000 individuals. All loci were homozygous, indicating that the species is strongly selfing. Populations consisted of a few common genotypes and variable numbers of rare genotypes. Small sample sizes (n = 10 individuals) were adequate for distinguishing among populations, but larger sample sizes were needed to characterize more diverse populations, particularly in terms...
Although polygyny can potentially increase male reproductive success, the benefits of this strategy could be offset by losses to extra-pair paternity or reduced offspring survival. We developed microsatellite markers to assess the influence of extrapair offspring (EPO) on reproductive success and paternity in monogamous and polygynous pairs of the facultatively polygynous Southwestern Willow Flycatcher (Empidonax traillii extimus). Based on genotypes of 140 offspring from 56 clutches over six years, 14% of nestlings in our study population were extra-pair offspring, with 23% of all successful nests containing at least one EPO. We found that polygynous males produced 2.11 0.35 offspring per season, compared to 1.15...


    map background search result map search result map Correlation between molecular markers and adaptively significant genetic variation in Bromus tectorum (Poaceae), an inbreedingannual grass Ecological significance of microsatellite variation in western North American populations of Bromus tectorum Geographic isolation, genetic divergence, and ecological non-exchangeability define ESUs in a threatened sky-island rattlesnake Across the great divide: genetic forensics reveals misidentification of endangered cutthroat trout populations. Genetic recapture identifies long-distance breeding dispersal in Greater Sage-Grouse (Centrocercus urophasianus) Geographic isolation, genetic divergence, and ecological non-exchangeability define ESUs in a threatened sky-island rattlesnake Genetic recapture identifies long-distance breeding dispersal in Greater Sage-Grouse (Centrocercus urophasianus) Across the great divide: genetic forensics reveals misidentification of endangered cutthroat trout populations. Correlation between molecular markers and adaptively significant genetic variation in Bromus tectorum (Poaceae), an inbreedingannual grass Ecological significance of microsatellite variation in western North American populations of Bromus tectorum