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"Larson, Matthew D"
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Breeding Snowy Owls Are Obligate Lemming Predators in Utqiaġvik, Alaska: Results from 30 Years of Study
For 30 years (1992–2021), we collected pellets and pellet fragments and recorded prey cached in Snowy Owl (Bubo scandiacus) nests during the breeding season in Utqiaġvik, Alaska. About 14,000 pellets from an estimated 700 Snowy Owls yielded 43,689 prey items, while caches in 284 nests yielded 3334 prey items. The owls ate thirty-seven species of vertebrates: one species of fish, five species of mammals, and thirty-one species of birds. Based on the pellet analysis, lemmings represented 99.0% of the total prey, with brown lemmings (Lemmus trimucronatus) representing 94.6%, collared lemmings (Dicrostonyx groenlandicus) representing 3.1%, and unidentified lemmings representing 1.3%. All other species were <1%. Based on the prey cached in nests, lemmings represented about 90.0% (89.9%) of the total prey (n = 3334), with brown lemmings representing 88.0% (87.9%), collared lemmings representing 1.9%, and unidentified lemmings representing <1%. Birds represented only 10.0% of the prey cached in nests, although many species were eaten. Food niche breadth (FNB) and dietary evenness (DIEV) scores from pellets were narrow for the prey identified within a group or species. FNB and DIEV scores from the prey cached in nests were also narrow for the prey identified within a group or species. There was almost complete dietary overlap when comparing the prey from pellets with the prey from caches. Biomass estimates from brown lemmings (178 kg) cached in nests were 59 times more than those from collared lemmings (3 kg). Biomass estimates for large birds were misleading, as the owls mainly ate the breast, humerus, and femur muscles. Our study supports a general consensus that Snowy Owls are obligate lemming specialists during the breeding season in Utqiaġvik. In fact, they depend almost entirely on one species of lemming—the brown lemming. Consequently, anthropogenic or natural factors that impact lemming populations and distributions will directly affect Snowy Owl populations.
Journal Article
A Worldwide Review of Snowy Owl Feeding Ecology: The Importance of Lemmings and Voles in a Changing Climate
We compared Snowy Owl feeding ecology from 15 breeding season studies throughout Nearctic and Palearctic circumpolar regions. We used raw data and information theory to assess the owls’ feeding niche. Combined studies yielded 59,923 prey items, of which 59,585 were used for calculations. Overall, mean food niche breadth (FNB) was narrow: H′ = 1.95; R = 1.60, D = 0.526. In 10 of 15 studies, lemmings were > 71.8% of the owls’ diet. In four studies, Lemmus was > 90% of the diet, and in three studies Dicrostonyx was >90% of the diet. In three other studies, Lemmus represented 71.8%, 73.8%, and 84.0% of the diet. In one study, Lemmus and Dicrostonyx were about equal: 49.1% and 47.5%. In the four remaining studies, Microtus and Clethrionomys voles were important. In contrast, of 5888 winter prey items from seven North American studies, the mean FNB (H′ = 4.61) was twice that of 15 breeding season scores, FNB (H’ = 1.95). The Snowy Owl is primarily an obligate lemming predator for breeding. Changes to population ecology and distribution of lemmings due to climate change will have direct affects and effects on the Snowy Owls’ reproductive output. The conservation of Snowy Owls is the conservation of lemmings.
Journal Article
Chloroplast 2010: A Database for Large-Scale Phenotypic Screening of Arabidopsis Mutants
Large-scale phenotypic screening presents challenges and opportunities not encountered in typical forward or reverse genetics projects. We describe a modular database and laboratory information management system that was implemented in support of the Chloroplast 2010 Project, an Arabidopsis (Arabidopsis thaliana) reverse genetics phenotypic screen of more than 5,000 mutants (http://bioinfo.bch.msu.edu/2010_LIMS; www.plastid.msu.edu). The software and laboratory work environment were designed to minimize operator error and detect systematic process errors. The database uses Ruby on Rails and Flash technologies to present complex quantitative and qualitative data and pedigree information in a flexible user interface. Examples are presented where the database was used to find opportunities for process changes that improved data quality. We also describe the use of the data-analysis tools to discover mutants defective in enzymes of leucine catabolism (heteromeric mitochondrial S-methylcrotonyl-coenzyme A carboxylase [Atlg03090 and At4g34030] and putative hydroxymethylglutarylcoenzyme A lyase [At2g26800]) based upon a syndrome of pleiotropic seed amino acid phenotypes that resembles previously described isovaleryl coenzyme A dehydrogenase (At3g45300) mutants. In vitro assay results support the computational annotation of At2g26800 as hydroxymethylglutaryl-coenzyme A lyase.
Journal Article
A multisystem, dimensional interplay of assets versus adversities: Revised benevolent childhood experiences (BCEs) in the context of childhood maltreatment, threat, and deprivation
This study expanded the Benevolent Childhood Experiences scale (termed the “BCEs-Original” scale) with 10 new multisystem items and identified a subset of items (termed the “BCEs-Revised” scale) that are systematically less commonly reported across samples. Total BCEs-Revised scores were tested against total BCEs-Original scores and three dimensions of childhood adversity (maltreatment, threat, and deprivation) as predictors of young adulthood mental health problems (depression, anxiety, and PTSD symptoms). Hypotheses expected stronger inverse associations of BCEs-Revised scores than BCEs-Original scores with all mental health problems. Participants were 1,746 U.S. young adults (M = 26.6 years, SD = 4.7, range = 19–35 years; 55.3% female, 42.4% male, 2.3% gender non-conforming; 67.0% White, 10.3% Asian, 8.6% Black, 8.4% Latine, 5.7% other) who completed a 20-item BCEs scale and well-validated instruments on childhood adversities and mental health problems. Compared to BCEs-Original scores, BCEs-Revised scores were significantly more strongly inversely associated with all mental health outcomes. Compared to childhood threat and deprivation, maltreatment was significantly more strongly associated with PTSD symptoms. After controlling for current depression symptoms, BCEs-Revised scores interacted with maltreatment to predict PTSD symptoms. Maltreatment and BCEs-Revised scores also influenced PTSD symptoms in person-oriented analyses. The BCEs-Revised scale has strong psychometric properties and unique strengths in research and practice. Implications for multisystem resilience are discussed.
Journal Article
Comparative genomics of two closely related unicellular thermo-acidophilic red algae, Galdieria sulphuraria and Cyanidioschyzon merolae, reveals the molecular basis of the metabolic flexibility of Galdieria sulphuraria and significant differences in carbohydrate metabolism of both algae
Unicellular algae serve as models for the study and discovery of metabolic pathways, for the functional dissection of cell biological processes such as organellar division and cell motility, and for the identification of novel genes and gene functions. The recent completion of several algal genome sequences and expressed sequence tag collections and the establishment of nuclear and organellar transformation methods has opened the way for functional genomics approaches using algal model systems. The thermo-acidophilic unicellular red alga Galdieria sulphuraria represents a particularly interesting species for a genomics approach owing to its extraordinary metabolic versatility such as heterotrophic and mixotrophic growth on more than 50 different carbon sources and its adaptation to hot acidic environments. However, the ab initio prediction of genes required for unknown metabolic pathways from genome sequences is not trivial. A compelling strategy for gene identification is the comparison of similarly sized genomes of related organisms with different physiologies. Using this approach, candidate genes were identified that are critical to the metabolic versatility of Galdieria. Expressed sequence tags and high-throughput genomic sequence reads covering >70% of the G. sulphuraria genome were compared to the genome of the unicellular, obligate photoautotrophic red alga Cyanidioschyzon merolae. More than 30% of the Galdieria sequences did not relate to any of the Cyanidioschyzon genes. A closer inspection of these sequences revealed a large number of membrane transporters and enzymes of carbohydrate metabolism that are unique to Galdieria. Based on these data, it is proposed that genes involved in the uptake of reduced carbon compounds and enzymes involved in their metabolism are crucial to the metabolic flexibility of G. sulphuraria.
Journal Article
Identification of Genes with Potential Roles in Apple Fruit Development and Biochemistry through Large-Scale Statistical Analysis of Expressed Sequence Tags
Advanced studies of apple (Malus domestica Borkh) development, physiology, and biochemistry have been hampered by the lack of appropriate genomics tools. One exception is the recent acquisition of extensive expressed sequence tag (EST) data. The entire available EST dataset for apple resulted from the efforts of at least 20 contributors and was derived from more than 70 cDNA libraries representing diverse transcriptional profiles from a variety of organs, fruit parts, developmental stages, biotic and abiotic stresses, and from at least nine cultivars. We analyzed apple EST sequences available in public databanks using statistical algorithms to identify those apple genes that are likely to be highly expressed in fruit, expressed uniquely or preferentially in fruit, and/or temporally or spatially regulated during fruit growth and development. We applied these results to the analysis of biochemical pathways involved in biosynthesis of precursors for volatile esters and identified a subset of apple genes that may participate in generating flavor and aroma components found in mature fruit.
Journal Article
Breeding Status of Flammulated Owls in Montana
Despite listing as a sensitive Species of Concern, the breeding status and biology of Flammulated Owls (Otus flammeolus = Psiloscops flammeolus) has been little studied in Montana. Compared to occurrence, breeding evidence is minimal. As of 2012, 664 records of Flammulated Owls existed in the Montana Natural Heritage Program database: 23 breeding and 641 occurrence records. From 2008 through 2012, we monitored 57 trees containing 131 cavities in 13 Flammulated Owl territories and documented 7 nests. We also documented the first tangible evidence of site fidelity by both sexes in Montana. Long-term, rigorous study of breeding biology and habitat is urgently needed to develop complete, accurate, and robust models for habitat management, and ultimately conservation of this migratory, forest-dwelling owl in Montana.
Journal Article
Chloroplast 2010: A Database for Large-Scale Phenotypic Screening of Arabidopsis Mutants1WOA
Large-scale phenotypic screening presents challenges and opportunities not encountered in typical forward or reverse genetics projects. We describe a modular database and laboratory information management system that was implemented in support of the Chloroplast 2010 Project, an Arabidopsis (Arabidopsis thaliana) reverse genetics phenotypic screen of more than 5,000 mutants (http://bioinfo.bch.msu.edu/2010_LIMS; www.plastid.msu.edu). The software and laboratory work environment were designed to minimize operator error and detect systematic process errors. The database uses Ruby on Rails and Flash technologies to present complex quantitative and qualitative data and pedigree information in a flexible user interface. Examples are presented where the database was used to find opportunities for process changes that improved data quality. We also describe the use of the data-analysis tools to discover mutants defective in enzymes of leucine catabolism (heteromeric mitochondrial 3-methylcrotonyl-coenzyme A carboxylase [At1g03090 and At4g34030] and putative hydroxymethylglutaryl-coenzyme A lyase [At2g26800]) based upon a syndrome of pleiotropic seed amino acid phenotypes that resembles previously described isovaleryl coenzyme A dehydrogenase (At3g45300) mutants. In vitro assay results support the computational annotation of At2g26800 as hydroxymethylglutaryl-coenzyme A lyase.
Journal Article