Fred W Allendorf

Publications (40)264.5 Total impact

• Article: Genomic patterns of introgression in rainbow and westslope cutthroat trout illuminated by overlapping paired-end RAD sequencing.

  Paul A Hohenlohe, Mitch D Day, Stephen J Amish, Michael R Miller, Nick Kamps-Hughes, Matthew C Boyer, Clint C Muhlfeld, Fred W Allendorf, Eric A Johnson, Gordon Luikart
  [show abstract] [hide abstract]
  ABSTRACT: Rapid and inexpensive methods for genomewide single nucleotide polymorphism (SNP) discovery and genotyping are urgently needed for population management and conservation. In hybridized populations, genomic techniques that can identify and genotype thousands of species-diagnostic markers would allow precise estimates of population- and individual-level admixture as well as identification of 'super invasive' alleles, which show elevated rates of introgression above the genomewide background (likely due to natural selection). Techniques like restriction-site-associated DNA (RAD) sequencing can discover and genotype large numbers of SNPs, but they have been limited by the length of continuous sequence data they produce with Illumina short-read sequencing. We present a novel approach, overlapping paired-end RAD sequencing, to generate RAD contigs of >300-400 bp. These contigs provide sufficient flanking sequence for design of high-throughput SNP genotyping arrays and strict filtering to identify duplicate paralogous loci. We applied this approach in five populations of native westslope cutthroat trout that previously showed varying (low) levels of admixture from introduced rainbow trout (RBT). We produced 77 141 RAD contigs and used these data to filter and genotype 3180 previously identified species-diagnostic SNP loci. Our population-level and individual-level estimates of admixture were generally consistent with previous microsatellite-based estimates from the same individuals. However, we observed slightly lower admixture estimates from genomewide markers, which might result from natural selection against certain genome regions, different genomic locations for microsatellites vs. RAD-derived SNPs and/or sampling error from the small number of microsatellite loci (n = 7). We also identified candidate adaptive super invasive alleles from RBT that had excessively high admixture proportions in hybridized cutthroat trout populations.
  Molecular Ecology 02/2013; · 5.52 Impact Factor
• Article: Hunting Effects on Favourable Conservation Status of Highly Inbred Swedish Wolves.

  Linda Laikre, Mija Jansson, Fred W Allendorf, Sven Jakobsson, Nils Ryman
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  ABSTRACT: The wolf (Canis lupus) is classified as endangered in Sweden by the Swedish Species Information Centre, which is the official authority for threat classification. The present population, which was founded in the early 1980s, descends from 5 individuals. It is isolated and highly inbred, and on average individuals are more related than siblings. Hunts have been used by Swedish authorities during 2010 and 2011 to reduce the population size to its upper tolerable level of 210 wolves. European Union (EU) biodiversity legislation requires all member states to promote a concept called "favourable conservation status" (FCS) for a series of species including the wolf. Swedish national policy stipulates maintenance of viable populations with sufficient levels of genetic variation of all naturally occurring species. Hunting to reduce wolf numbers in Sweden is currently not in line with national and EU policy agreements and will make genetically based FCS criteria less achievable for this species. We suggest that to reach FCS for the wolf in Sweden the following criteria need to be met: (1) a well-connected, large, subdivided wolf population over Scandinavia, Finland, and the Russian Karelia-Kola region should be reestablished, (2) genetically effective size (N(e) ) of this population is in the minimum range of N(e) = 500-1000, (3) Sweden harbors a part of this total population that substantially contributes to the total N(e) and that is large enough to not be classified as threatened genetically or according to IUCN criteria, and (4) average inbreeding levels in the Swedish population are <0.1. Efectos de la Cacería sobre el Estatus de Conservación Favorable de Lobos Suecos con Endogamia Alta.
  Conservation Biology 01/2013; · 4.69 Impact Factor
• Article: Securing the Demographic and Genetic Future of Tuatara through Assisted Colonization.

  Kimberly A Miller, Hilary C Miller, Jennifer A Moore, Nicola J Mitchell, Alison Cree, Fred W Allendorf, Stephen D Sarre, Susan N Keall, Nicola J Nelson
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  ABSTRACT:   Climate change poses a particular threat to species with fragmented distributions and little or no capacity to migrate. Assisted colonization, moving species into regions where they have not previously occurred, aims to establish populations where they are expected to survive as climatic envelopes shift. However, adaptation to the source environment may affect whether species successfully establish in new regions. Assisted colonization has spurred debate among conservation biologists and ecologists over whether the potential benefits to the threatened species outweigh the potential disruption to recipient communities. In our opinion, the debate has been distracted by controversial examples, rather than cases where assisted colonization may be a viable strategy. We present a strategic plan for the assisted migration of tuatara (Sphenodon punctatus), an endemic New Zealand reptile. The plan includes use of extant populations as reference points for comparisons with assisted-colonization populations with respect to demography, phenotypic plasticity, and phenology; optimization of genetic variation; research to fill knowledge gaps; consideration of host and recipient communities; and inclusion of stakeholders in the planning stage. When strategically planned and monitored, assisted colonization could meet conservation and research goals and ultimately result in the establishment of long-term sustainable populations capable of persisting during rapid changes in climate.
  Conservation Biology 07/2012; 26(5):790-798. · 4.69 Impact Factor
• Article: Harnessing genomics for delineating conservation units.

  W Chris Funk, John K McKay, Paul A Hohenlohe, Fred W Allendorf
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  ABSTRACT: Genomic data have the potential to revolutionize the delineation of conservation units (CUs) by allowing the detection of adaptive genetic variation, which is otherwise difficult for rare, endangered species. In contrast to previous recommendations, we propose that the use of neutral versus adaptive markers should not be viewed as alternatives. Rather, neutral and adaptive markers provide different types of information that should be combined to make optimal management decisions. Genetic patterns at neutral markers reflect the interaction of gene flow and genetic drift that affects genome-wide variation within and among populations. This population genetic structure is what natural selection operates on to cause adaptive divergence. Here, we provide a new framework to integrate data on neutral and adaptive markers to protect biodiversity.
  Trends in Ecology & Evolution 06/2012; 27(9):489-96. · 15.75 Impact Factor
• Article: RAD sequencing yields a high success rate for westslope cutthroat and rainbow trout species-diagnostic SNP assays.

  Stephen J Amish, Paul A Hohenlohe, Sally Painter, Robb F Leary, Clint Muhlfeld, Fred W Allendorf, Gordon Luikart
  [show abstract] [hide abstract]
  ABSTRACT: Hybridization with introduced rainbow trout threatens most native westslope cutthroat trout populations. Understanding the genetic effects of hybridization and introgression requires a large set of high-throughput, diagnostic genetic markers to inform conservation and management. Recently, we identified several thousand candidate single-nucleotide polymorphism (SNP) markers based on RAD sequencing of 11 westslope cutthroat trout and 13 rainbow trout individuals. Here, we used flanking sequence for 56 of these candidate SNP markers to design high-throughput genotyping assays. We validated the assays on a total of 92 individuals from 22 populations and seven hatchery strains. Forty-six assays (82%) amplified consistently and allowed easy identification of westslope cutthroat and rainbow trout alleles as well as heterozygote controls. The 46 SNPs will provide high power for early detection of population admixture and improved identification of hybrid and nonhybridized individuals. This technique shows promise as a very low-cost, reliable and relatively rapid method for developing and testing SNP markers for nonmodel organisms with limited genomic resources.
  Molecular Ecology Resources 06/2012; 12(4):653-60. · 3.06 Impact Factor
• Article: Genetic structure and individual performance following a recent founding event in a small lizard

  Kimberly A. Miller, David R. Towns, Fred W. Allendorf, Peter A. Ritchie, Nicola J. Nelson
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  ABSTRACT: Reintroduced populations of threatened species are often founded by a small number of individuals, but maximising genetic diversity is often a criterion for founder selection. Reintroduction of pregnant females has been proposed as a means of maximising productivity and genetic diversity, but it is unclear whether the release of pregnant females increases the effective number of founders. Ten male and 20 gravid female egg-laying skinks (Oligosoma suteri) were reintroduced to Korapuki Island from Green Island, New Zealand in 1992. We sampled the populations on both Green and Korapuki Islands to examine the effect of reintroduction on the genetic structure and fitness of egg-laying skinks following release. The population on Korapuki Island showed multiple genetic signatures of a bottleneck that were not detected in the population on Green Island. At the individual level, juveniles on Korapuki Island were more homozygous than adults on Korapuki and Green Islands. However, we did not find evidence of inbreeding depression using two performance-based surrogates of fitness. Further, the population on Korapuki Island had a significantly larger effective population size than would have been expected by reintroduction of 30 skinks, based on 10,000 simulated populations. The reintroduction of gravid females aided in increasing the effective number of founders, and may be a viable option for maximizing genetic diversity in reintroduced populations, particularly for long-lived species. However, the continued loss of genetic variation in reintroduced populations may have more insidious long-term consequences, such as the loss of adaptive potential, which cannot be assessed in the short-term. KeywordsGenetic bottleneck–Heterozygosity-fitness correlations–Locomotion– Oligosoma suteri –Reintroduction–Translocation
  Conservation Genetics 04/2012; 12(2):461-473. · 1.61 Impact Factor
• Article: Fourteen microsatellite loci cross-amplify in all five kiwi species (Apteryx spp.) and reveal extremely low genetic variation in little spotted kiwi (A. owenii)

  Kristina M. Ramstad, Monika Pfunder, Hugh A. Robertson, Rogan M. Colbourne, Fred W. Allendorf, Charles H. Daugherty
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  ABSTRACT: We present 14 microsatellite loci that were isolated from little spotted kiwi (LSK, Apteryx owenii). All loci cross-amplify in all kiwi species currently recognized except for one locus in a single species. Little spotted kiwi exhibited lower variation at these loci (mean number of alleles, H E) than other kiwi species, despite the markers having been developed for polymorphism in LSK and a far greater number of LSK genotyped than kiwi of other species. Reliable cross-species amplification and polymorphism make these markers promising new tools for the management of New Zealand’s threatened kiwi. KeywordsKiwi- Apteryx -Microsatellites-Cross-species amplification-Conservation
  Conservation Genetics Resources 04/2012; 2:333-336. · 0.49 Impact Factor
• Source

  Available from: John K. Wenburg

  Article: Genetic variation and effective population size in isolated populations of coastal cutthroat trout

  Andrew R. Whiteley, Kim Hastings, John K. Wenburg, Chris A. Frissell, Jamie C. Martin, Fred W. Allendorf
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  ABSTRACT: Following glacial recession in southeast Alaska, waterfalls created by isostatic rebound have isolated numerous replicate populations of coastal cutthroat trout (Oncorhynchus clarkii clarkii) in short coastal streams. These replicate isolated populations offer an unusual opportunity to examine factors associated with the maintenance of genetic diversity. We used eight microsatellites to examine genetic variation within and differentiation among 12 population pairs sampled from above and below these natural migration barriers. Geological evidence indicated that the above-barrier populations have been isolated for 8,000–12,500years. Genetic differentiation among below-barrier populations (F ST=0.10, 95% C.I. 0.08–0.12) was similar to a previous study of more southern populations of this species. Above-barrier populations were highly differentiated from adjacent below-barrier populations (mean pairwise F ST=0.28; SD 0.18) and multiple lines of evidence were consistent with asymmetric downstream gene flow that varied among streams. Each above-barrier population had reduced within-population genetic variation when compared to the adjacent below-barrier population. Within-population genetic diversity was significantly correlated with the amount of available habitat in above-barrier sites. Increased genetic differentiation of above-barrier populations with lower genetic diversity suggests that genetic drift has been the primary cause of genetic divergence. Long-term estimates of N e based on loss of heterozygosity over the time since isolation were large (3,170; range 1,077–7,606) and established an upper limit for N e if drift were the only evolutionary process responsible for loss of genetic diversity. However, it is likely that a combination of mutation, selection, and gene flow have also contributed to the genetic diversity of above-barrier populations. Contemporary above-barrier N e estimates were much smaller than long-term N e estimates, not correlated with within-population genetic diversity, and not consistent with the amount of genetic variation retained, given the approximate 10,000-year period of isolation. The populations isolated by waterfalls in this study that occur in larger stream networks have retained substantial genetic variation, which suggests that the amount of habitat in headwater streams is an important consideration for maintaining the evolutionary potential of isolated populations. KeywordsGenetic diversity-Population structure-Isolated populations-Salmonid-Effective population size
  Conservation Genetics 04/2012; 11(5):1929-1943. · 1.61 Impact Factor
• Source

  Available from: fs.fed.us

  Article: Estimation of census and effective population sizes: the increasing usefulness of DNA-based approaches

  Gordon Luikart, Nils Ryman, David A. Tallmon, Michael K. Schwartz, Fred W. Allendorf
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  ABSTRACT: Population census size (N C) and effective population sizes (N e) are two crucial parameters that influence population viability, wildlife management decisions, and conservation planning. Genetic estimators of both N C and N e are increasingly widely used because molecular markers are increasingly available, statistical methods are improving rapidly, and genetic estimators complement or improve upon traditional demographic estimators. We review the kinds and applications of estimators of both N C and N e, and the often undervalued and misunderstood ratio of effective-to-census size (N e /N C). We focus on recently improved and well evaluated methods that are most likely to facilitate conservation. Finally, we outline areas of future research to improve N e and N C estimation in wild populations. KeywordsPopulation size estimation-Noninvasive sampling-Remote genetic monitoring-Abundance-Bottleneck- N e/N C ratio-Habitat fragmentation
  Conservation Genetics 04/2012; 11(2):355-373. · 1.61 Impact Factor
• Article: Historical and contemporary DNA indicate fisher decline and isolation occurred prior to the European settlement of california.

  Jody M Tucker, Michael K Schwartz, Richard L Truex, Kristine L Pilgrim, Fred W Allendorf
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  ABSTRACT: Establishing if species contractions were the result of natural phenomena or human induced landscape changes is essential for managing natural populations. Fishers (Martes pennanti) in California occur in two geographically and genetically isolated populations in the northwestern mountains and southern Sierra Nevada. Their isolation is hypothesized to have resulted from a decline in abundance and distribution associated with European settlement in the 1800s. However, there is little evidence to establish that fisher occupied the area between the two extant populations at that time. We analyzed 10 microsatellite loci from 275 contemporary and 21 historical fisher samples (1880-1920) to evaluate the demographic history of fisher in California. We did not find any evidence of a recent (post-European) bottleneck in the northwestern population. In the southern Sierra Nevada, genetic subdivision within the population strongly influenced bottleneck tests. After accounting for genetic subdivision, we found a bottleneck signal only in the northern and central portions of the southern Sierra Nevada, indicating that the southernmost tip of these mountains may have acted as a refugium for fisher during the anthropogenic changes of the late 19(th) and early 20(th) centuries. Using a coalescent-based Bayesian analysis, we detected a 90% decline in effective population size and dated the time of decline to over a thousand years ago. We hypothesize that fisher distribution in California contracted to the two current population areas pre-European settlement, and that portions of the southern Sierra Nevada subsequently experienced another more recent bottleneck post-European settlement.
  PLoS ONE 01/2012; 7(12):e52803. · 4.09 Impact Factor
• Source

  Available from: oregonstate.edu

  Article: Next-generation RAD sequencing identifies thousands of SNPs for assessing hybridization between rainbow and westslope cutthroat trout.

  Paul A Hohenlohe, Stephen J Amish, Julian M Catchen, Fred W Allendorf, Gordon Luikart
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  ABSTRACT: The increased numbers of genetic markers produced by genomic techniques have the potential to both identify hybrid individuals and localize chromosomal regions responding to selection and contributing to introgression. We used restriction-site-associated DNA sequencing to identify a dense set of candidate SNP loci with fixed allelic differences between introduced rainbow trout (Oncorhynchus mykiss) and native westslope cutthroat trout (Oncorhynchus clarkii lewisi). We distinguished candidate SNPs from homeologs (paralogs resulting from whole-genome duplication) by detecting excessively high observed heterozygosity and deviations from Hardy-Weinberg proportions. We identified 2923 candidate species-specific SNPs from a single Illumina sequencing lane containing 24 barcode-labelled individuals. Published sequence data and ongoing genome sequencing of rainbow trout will allow physical mapping of SNP loci for genome-wide scans and will also provide flanking sequence for design of qPCR-based TaqMan(®) assays for high-throughput, low-cost hybrid identification using a subset of 50-100 loci. This study demonstrates that it is now feasible to identify thousands of informative SNPs in nonmodel species quickly and at reasonable cost, even if no prior genomic information is available.
  Molecular Ecology Resources 03/2011; 11 Suppl 1:117-22. · 3.06 Impact Factor
• Article: Why replication is important in landscape genetics: American black bear in the Rocky Mountains

  R. A. SHORT BULL, S. A. CUSHMAN, R. MACE, T. CHILTON, K. C. KENDALL, E. L. LANDGUTH, M.K. SCHWARTZ, K. MCKELVEY, FRED W. ALLENDORF, G. LUIKART
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  ABSTRACT: We investigated how landscape features influence gene flow of black bears by testing the relative support for 36 alternative landscape resistance hypotheses, including isolation by distance (IBD) in each of 12 study areas in the north central U.S. Rocky Mountains. The study areas all contained the same basic elements, but differed in extent of forest fragmentation, altitude, variation in elevation and road coverage. In all but one of the study areas, isolation by landscape resistance was more supported than IBD suggesting gene flow is likely influenced by elevation, forest cover, and roads. However, the landscape features influencing gene flow varied among study areas. Using subsets of loci usually gave models with the very similar landscape features influencing gene flow as with all loci, suggesting the landscape features influencing gene flow were correctly identified. To test if the cause of the variability of supported landscape features in study areas resulted from landscape differences among study areas, we conducted a limiting factor analysis. We found that features were supported in landscape models only when the features were highly variable. This is perhaps not surprising but suggests an important cautionary note – that if landscape features are not found to influence gene flow, researchers should not automatically conclude that the features are unimportant to the species’ movement and gene flow. Failure to investigate multiple study areas that have a range of variability in landscape features could cause misleading inferences about which landscape features generally limit gene flow. This could lead to potentially erroneous identification of corridors and barriers if models are transferred between areas with different landscape characteristics.
  Molecular Ecology 02/2011; 20(6):1092 - 1107. · 5.52 Impact Factor
• Source

  Available from: nau.edu

  Article: Why replication is important in landscape genetics: American black bear in the Rocky Mountains.

  R A Short Bull, S A Cushman, R Mace, T Chilton, K C Kendall, E L Landguth, M K Schwartz, K McKelvey, Fred W Allendorf, G Luikart
  [show abstract] [hide abstract]
  ABSTRACT: We investigated how landscape features influence gene flow of black bears by testing the relative support for 36 alternative landscape resistance hypotheses, including isolation by distance (IBD) in each of 12 study areas in the north central U.S. Rocky Mountains. The study areas all contained the same basic elements, but differed in extent of forest fragmentation, altitude, variation in elevation and road coverage. In all but one of the study areas, isolation by landscape resistance was more supported than IBD suggesting gene flow is likely influenced by elevation, forest cover, and roads. However, the landscape features influencing gene flow varied among study areas. Using subsets of loci usually gave models with the very similar landscape features influencing gene flow as with all loci, suggesting the landscape features influencing gene flow were correctly identified. To test if the cause of the variability of supported landscape features in study areas resulted from landscape differences among study areas, we conducted a limiting factor analysis. We found that features were supported in landscape models only when the features were highly variable. This is perhaps not surprising but suggests an important cautionary note - that if landscape features are not found to influence gene flow, researchers should not automatically conclude that the features are unimportant to the species' movement and gene flow. Failure to investigate multiple study areas that have a range of variability in landscape features could cause misleading inferences about which landscape features generally limit gene flow. This could lead to potentially erroneous identification of corridors and barriers if models are transferred between areas with different landscape characteristics.
  Molecular Ecology 01/2011; 20(6):1092-107. · 5.52 Impact Factor
• Source

  Available from: up.pt

  Article: Genomics and the future of conservation genetics.

  Fred W Allendorf, Paul A Hohenlohe, Gordon Luikart
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  ABSTRACT: We will soon have complete genome sequences from thousands of species, as well as from many individuals within species. This coming explosion of information will transform our understanding of the amount, distribution and functional significance of genetic variation in natural populations. Now is a crucial time to explore the potential implications of this information revolution for conservation genetics and to recognize limitations in applying genomic tools to conservation issues. We identify and discuss those problems for which genomics will be most valuable for curbing the accelerating worldwide loss of biodiversity. We also provide guidance on which genomics tools and approaches will be most appropriate to use for different aspects of conservation.
  Nature Reviews Genetics 10/2010; 11(10):697-709. · 38.08 Impact Factor
• Source

  Available from: umt.edu

  Article: What can genetics tell us about population connectivity?

  Winsor H Lowe, Fred W Allendorf
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  ABSTRACT: Genetic data are often used to assess 'population connectivity' because it is difficult to measure dispersal directly at large spatial scales. Genetic connectivity, however, depends primarily on the absolute number of dispersers among populations, whereas demographic connectivity depends on the relative contributions to population growth rates of dispersal vs. local recruitment (i.e. survival and reproduction of residents). Although many questions are best answered with data on genetic connectivity, genetic data alone provide little information on demographic connectivity. The importance of demographic connectivity is clear when the elimination of immigration results in a shift from stable or positive population growth to negative population growth. Otherwise, the amount of dispersal required for demographic connectivity depends on the context (e.g. conservation or harvest management), and even high dispersal rates may not indicate demographic interdependence. Therefore, it is risky to infer the importance of demographic connectivity without information on local demographic rates and how those rates vary over time. Genetic methods can provide insight on demographic connectivity when combined with these local demographic rates, data on movement behaviour, or estimates of reproductive success of immigrants and residents. We also consider the strengths and limitations of genetic measures of connectivity and discuss three concepts of genetic connectivity that depend upon the evolutionary criteria of interest: inbreeding connectivity, drift connectivity, and adaptive connectivity. To conclude, we describe alternative approaches for assessing population connectivity, highlighting the value of combining genetic data with capture-mark-recapture methods or other direct measures of movement to elucidate the complex role of dispersal in natural populations.
  Molecular Ecology 08/2010; 19(15):3038-51. · 5.52 Impact Factor
• Source

  Available from: Karen K Martien

  Article: When are genetic methods useful for estimating contemporary abundance and detecting population trends?

  David A Tallmon, Dave Gregovich, Robin S Waples, C Scott Baker, Jennifer Jackson, Barbara L Taylor, Eric Archer, Karen K Martien, Fred W Allendorf, Michael K Schwartz
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  ABSTRACT: The utility of microsatellite markers for inferring population size and trend has not been rigorously examined, even though these markers are commonly used to monitor the demography of natural populations. We assessed the ability of a linkage disequilibrium estimator of effective population size (N(e) ) and a simple capture-recapture estimator of abundance (N) to quantify the size and trend of stable or declining populations (true N = 100-10,000), using simulated Wright-Fisher populations. Neither method accurately or precisely estimated abundance at sample sizes of S = 30 individuals, regardless of true N. However, if larger samples of S = 60 or 120 individuals were collected, these methods provided useful insights into abundance and trends for populations of N = 100-500. At small population sizes (N = 100 or 250), precision of the N(e) estimates was improved slightly more by a doubling of loci sampled than by a doubling of individuals sampled. In general, monitoring N(e) proved a more robust means of identifying stable and declining populations than monitoring N over most of the parameter space we explored, and performance of the N(e) estimator is further enhanced if the N(e) /N ratio is low. However, at the largest population size (N = 10,000), N estimation outperformed N(e) . Both methods generally required ≥ 5 generations to pass between sampling events to correctly identify population trend.
  Molecular Ecology Resources 07/2010; 10(4):684-692. · 3.06 Impact Factor
• Source

  Available from: fs.fed.us

  Article: Do male and female black‐backed woodpeckers respond differently to gaps in habitat?

  Jennifer C. Pierson, Fred W. Allendorf, Victoria Saab, Pierre Drapeau, Michael K. Schwartz
  [show abstract] [hide abstract]
  ABSTRACT: We used population- and individual-based genetic approaches to assess barriers to movement in black-backed woodpeckers (Picoides arcticus), a fire-specialist that mainly occupies the boreal forest in North America. We tested if male and female woodpeckers exhibited the same movement patterns using both spatially implicit and explicit genetic analyses to define population structure and movement patterns of both sexes among populations. Three genetic groups were identified, a large, genetically continuous population that spans from the Rocky Mountains to Quebec, a small isolated population in South Dakota and a separate population in the western portion of their distribution (Oregon). Patterns of genetic diversity suggest extensive gene flow mediated by both males and females within the continuous boreal forest. However, male-mediated gene flow is the main form of connectivity between the continuously distributed group and the smaller populations of South Dakota and Oregon that are separated by large areas of unforested habitat, which apparently serves as a barrier to movement of female woodpeckers.
  Evolutionary Applications 04/2010; 3(3):263 - 278. · 4.92 Impact Factor
• Article: Demographic effects of temperature‐dependent sex determination: will tuatara survive global warming?

  NICOLA J. MITCHELL, FRED W. ALLENDORF, SUSAN N. KEALL, CHARLES H. DAUGHERTY, NICOLA J. NELSON
  [show abstract] [hide abstract]
  ABSTRACT: Global climate change is of particular concern for small and isolated populations of reptiles with temperature-dependent sex determination because low genetic variation can limit adaptive response in pivotal temperatures, leading to skewed sex ratios. We explore the demographic consequences of skewed sex ratios on the viability of a tuatara population characterized by low genetic diversity. We studied the rare species of tuatara (Sphenodon guntheri) on the 4 ha North Brother Island in New Zealand over two nesting seasons and captured 477 individuals, with a 60% male bias in the adult population. Females first breed at 15 years and have extremely low rates of gravidity, producing clutches of three to eight eggs every 9 years. Simulations of the population using population viability analysis showed that the current population is expected to persist for at least 2000 years at hatchling sex ratios of up to 75% male, but populations with 85% male hatchlings are expected to become extinct within approximately 300 years (some eight generations). Incorporation of inbreeding depression increased the probability of extinction under male biased sex ratios, with no simulated populations surviving at hatchling sex ratios >75% male. Because recent models have predicted that climate change could lead to the production of all male S. guntheri hatchlings by 2085, we examined whether periodic intervention to produce mixed or female biased sex ratios would allow the population to survive if only males were produced in natural nests. We show that intervention every 2–3 years could buffer the effects of climate change on population sex ratios, but translocation to cooler environs might be more cost-effective. Climate change threatens tuatara populations because neither modified nesting behaviour nor adaptive response of the pivotal temperature can modify hatchling sex ratios fast enough in species with long generation intervals.
  Global Change Biology 12/2009; 16(1):60 - 72. · 6.86 Impact Factor
• Article: Neglect of genetic diversity in implementation of the convention on biological diversity.

  Linda Laikre, Fred W Allendorf, Laurel C Aroner, C Scott Baker, David P Gregovich, Michael M Hansen, Jennifer A Jackson, Katherine C Kendall, Kevin McKelvey, Maile C Neel, Isabelle Olivieri, Nils Ryman, Michael K Schwartz, Ruth Short Bull, Jeffrey B Stetz, David A Tallmon, Barbara L Taylor, Christina D Vojta, Donald M Waller, Robin S Waples
  Conservation Biology 12/2009; 24(1):86-8. · 4.69 Impact Factor
• Source

  Available from: su.se

  Article: Importance of genetics in the interpretation of Favourable Conservation Status.

  Linda Laikre, Torbjörn Nilsson, Craig R Primmer, Nils Ryman, Fred W Allendorf
  Conservation Biology 12/2009; 23(6):1378-81. · 4.69 Impact Factor