Sandhill Crane Roost Selection, Human Disturbance, and Forage Resources

Sites used for roosting represent a key habitat requirement for many species of birds because availability and quality of roost sites can influence individual fitness. Birds select roost sites based on numerous factors, requirements, and motivations, and selection of roosts can be dynamic in time and space because of various ecological and environmental influences. For sandhill cranes (Antigone canadensis) at their main spring staging area along the Platte River in south-central Nebraska, USA, past investigations of roosting cranes focuse donphysical channel characteristics related to perceived security as motivating roost distribution.We used 6,310 roost sites selected by 313 sandhill cranes over 5 spring migration seasons (2003–2007) to quantify resource selection functions of roost sites on the central Platte River using a discrete choice analysis. Sandhill cranes generally showed stronger selection for wider channels with shorter bank vegetation situated farther from potential human disturbance features such as roads, bridges, and dwellings.Furthermore, selection for roost sites with preferable physical characteristics (wide channels with short bank vegetation) was more resilient to nearby disturbance features than more narrow channels with taller bank vegetation. The amount of cornfields surrounding sandhill crane roost sites positively influenced relative probability of use but only for more narrow channels \u3c100m and those with shorter bank vegetation. We confirmed key resource features that sandhill cranes selected at river channels along the Platte River, and after incorporating spatial variation due to human disturbance, our understanding of roost site selection was more robust, providing insights on how disturbance may interact with physical habitat features. Managers can use information on roost-site selection when developing plans to increase probability of crane use at existing roost sites and to identify new areas for potential use if existing sites become limited

On Generalized Additive Models for Representation of Solar EUV Irradiance

In the context of space weather forecasting, solar EUV irradiance specification is needed on multiple time scales, with associated uncertainty quantification for determining the accuracy of downstream parameters. Empirical models of irradiance often rely on parametric fits between irradiance in several bands and various solar indices. We build upon these empirical models by using Generalized Additive Models (GAMs) to represent solar irradiance. We apply the GAM approach in two steps: (a) A GAM is fitted between FISM2 irradiance and solar indices F10.7, Revised Sunspot Number, and the Lyman-α solar index. (b) A second GAM is fit to model the residuals of the first GAM with respect to FISM2 irradiance. We evaluate the performance of this approach during Solar Cycle 24 using GAMs driven by known solar indices as well as those forecasted 3 days ahead with an autoregressive modeling approach. We demonstrate negligible dependence of performance on solar cycle and season, and we assess the efficacy of the GAM approach across different wavelengths

A TLE-based Algorithm for Correcting Empirical Model Densities during Geomagnetic Storms

Neutral densities increase up to 800% during geomagnetic storms. Satellite two-line element sets (TLEs) show increased orbital decay during geomagnetic storms from increased drag

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Mortality in Aransas-Wood Buffalo Whooping Cranes: Timing, Location, and Causes

The Aransas-Wood Buffalo Population (AWBP) of Whooping Cranes (Grus americana) has experienced a population growth rate of approximately 4% for multiple decades (Butler et al., 2014a; Miller et al., 1974). Population growth for long-lived species of birds is generally highly sensitive to variation in adult mortality rates (Sæther and Bakke, 2000). A population model for endangered Red-crowned Cranes (Grus japonensis) in Japan conforms to this pattern, where growth rate is most sensitive to adult mortality (Masatomi et al., 2007). Earlier analyses observed that the AWBP growth rate increased in the mid-1950s and that this increase was likely caused by reduced annual mortality rates, even while the population experienced slightly decreasing natality (Binkley and Miller, 1988; Miller et al., 1974). A more contemporary analysis of the AWBP determined that approximately 50% of variation in annual population growth could be explained by variation in annual mortality (Butler et al., 2014a). Therefore, as a vital rate, mortality is critical to the maintained growth of the AWBP

Substrate-selective repair and restart of replication forks by DNA translocases

Stalled replication forks are sources of genetic instability. Multiple fork-remodeling enzymes are recruited to stalled forks, but how they work to promote fork restart is poorly understood. By combining ensemble biochemical assays and single-molecule studies with magnetic tweezers, we show that SMARCAL1 branch migration and DNA-annealing activities are directed by the single-stranded DNA-binding protein RPA to selectively regress stalled replication forks caused by blockage to the leading-strand polymerase and to restore normal replication forks with a lagging-strand gap. We unveil the molecular mechanisms by which RPA enforces SMARCAL1 substrate preference. E. coli RecG acts similarly to SMARCAL1 in the presence of E. coli SSB, whereas the highly related human protein ZRANB3 has different substrate preferences. Our findings identify the important substrates of SMARCAL1 in fork repair, suggest that RecG and SMARCAL1 are functional orthologs, and provide a comprehensive model of fork repair by these DNA translocases

Development of high amylose wheat through TILLING

BACKGROUND: Wheat (Triticum spp.) is an important source of food worldwide and the focus of considerable efforts to identify new combinations of genetic diversity for crop improvement. In particular, wheat starch composition is a major target for changes that could benefit human health. Starches with increased levels of amylose are of interest because of the correlation between higher amylose content and elevated levels of resistant starch, which has been shown to have beneficial effects on health for combating obesity and diabetes. TILLING (Targeting Induced Local Lesions in Genomes) is a means to identify novel genetic variation without the need for direct selection of phenotypes. RESULTS: Using TILLING to identify novel genetic variation in each of the A and B genomes in tetraploid durum wheat and the A, B and D genomes in hexaploid bread wheat, we have identified mutations in the form of single nucleotide polymorphisms (SNPs) in starch branching enzyme IIa genes (SBEIIa). Combining these new alleles of SBEIIa through breeding resulted in the development of high amylose durum and bread wheat varieties containing 47-55% amylose and having elevated resistant starch levels compared to wild-type wheat. High amylose lines also had reduced expression of SBEIIa RNA, changes in starch granule morphology and altered starch granule protein profiles as evaluated by mass spectrometry. CONCLUSIONS: We report the use of TILLING to develop new traits in crops with complex genomes without the use of transgenic modifications. Combined mutations in SBEIIa in durum and bread wheat varieties resulted in lines with significantly increased amylose and resistant starch contents