Shorebirds Breed in Unusually High Densities in the Teshekpuk Lake Special Area, Alaska

On the Arctic Coastal Plain of the National Petroleum Reserve-Alaska (NPR-A), the Teshekpuk Lake Special Area (TLSA) was recognized to protect outstanding wildlife values. Although information has accumulated on the TLSA’s value to caribou and waterfowl, its importance to breeding shorebirds remains largely unquantified. Therefore, we undertook a broad-scale ground study to estimate the population size and density of shorebirds breeding in the TLSA. From a series of plot surveys conducted from 2006 to 2008, we estimated a detection-adjusted total breeding population of more than 573 000 shorebirds and an overall density of 126 shorebirds/km2. Most shorebird species had their greatest densities on the Outer Coastal Plain or had approximately equal densities on Outer and Inner Coastal Plains; only two species had their greatest densities on the Inner Coastal Plain. The greatest densities of breeding shorebirds occurred immediately around Teshekpuk Lake. The TLSA supported more than 10% of the biogeographic populations of black-bellied plover (Pluvialis squatarola), semipalmated sandpiper (Calidris pusilla), and dunlin (C. alpina). Breeding shorebird density in the TLSA is one of the highest in the NPR-A, on Alaska’s North Slope, and throughout the circumpolar Arctic. Our results, coupled with previous information on waterfowl and caribou, indicate that the area around Teshekpuk Lake and the recognized goose molting area northeast of the lake should be protected from oil and gas development.Sur la plaine côtière arctique de la réserve pétrolière nationale-Alaska (NPRA), la région spéciale du lac Teshekpuk (TLSA) a été créée dans le but de protéger les valeurs exceptionnelles de la faune. Même s’il existe beaucoup d’information sur la valeur du caribou et de la sauvagine de la TLSA, l’importance qu’elle revêt en matière d’oiseaux de rivage nicheurs demeure peu quantifiée. Nous avons par conséquent entrepris de faire une étude sur le terrain à grande échelle pour estimer la taille et la densité de la population d’oiseaux de rivage nichant dans la TLSA. À partir d’une série d’enquêtes réalisées de 2006 à 2008, nous avons estimé que le total redressé en fonction de la détection de la population nicheuse s’établissait à plus de 573 000 oiseaux de rivage, et que la densité générale s’élevait à 126 oiseaux de rivage/km2. Les plus grandes densités de la plupart des espèces d’oiseaux de rivage se trouvaient sur la plaine côtière extérieure ou encore, les densités étaient environ égales entre les plaines côtières intérieure et extérieure. Seulement deux espèces avaient leurs plus fortes densités sur la plaine côtière intérieure. Les plus grandes densités d’oiseaux de rivage se manifestaient immédiatement autour du lac Teshekpuk. La TLSA accueillait plus de 10 % des populations biogéographiques de pluviers argentés (Pluvialis squatarola), de bécasseaux semipalmés (Calidris pusilla) et de bécasseaux variables (C. alpina). La densité d’oiseaux nicheurs dans la TLSA est l’une des plus élevées de la NPR-A, sur le versant nord de l’Alaska et à l’échelle de l’Arctique circumpolaire. Nos résultats, jumelés à l’information obtenue antérieurement au sujet de la sauvagine et du caribou, indiquent que la région autour du lac Teshekpuk et la région reconnue pour la mue des oies au nord-est du lac devraient être protégées contre la mise en valeur pétrolière et gazière

Observation of a multimode plasma response and its relationship to density pumpout and edge-localized mode suppression

Density pumpout and edge-localized mode (ELM) suppression by applied n=2 magnetic fields in low-collisionality DIII-D plasmas are shown to be correlated with the magnitude of the plasma response driven on the high-field side (HFS) of the magnetic axis but not the low-field side (LFS) midplane. These distinct responses are a direct measurement of a multimodal magnetic plasma response, with each structure preferentially excited by a different n=2 applied spectrum and preferentially detected on the LFS or HFS. Ideal and resistive magneto-hydrodynamic (MHD) calculations find that the LFS measurement is primarily sensitive to the excitation of stable kink modes, while the HFS measurement is primarily sensitive to resonant currents (whether fully shielding or partially penetrated). The resonant currents are themselves strongly modified by kink excitation, with the optimal applied field pitch for pumpout and ELM suppression significantly differing from equilibrium field alignment.This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Awards No. DE-FC02-04ER54698, No. DE-AC02-09CH11466, No. DE-FG02-04ER54761, No. DE-AC05-06OR23100, No. DE-SC0001961, and No. DE-AC05-00OR22725. S. R. H. was supported by AINSE and ANSTO

Bounds and dynamics for empirical game theoretic analysis

This paper provides several theoretical results for empirical game theory. Specifically, we introduce bounds for empirical game theoretical analysis of complex multi-agent interactions. In doing so we provide insights in the empirical meta game showing that a Nash equilibrium of the estimated meta-game is an approximate Nash equilibrium of the true underlying meta-game. We investigate and show how many data samples are required to obtain a close enough approximation of the underlying game. Additionally, we extend the evolutionary dynamics analysis of meta-games using heuristic payoff tables (HPTs) to asymmetric games. The state-of-the-art has only considered evolutionary dynamics of symmetric HPTs in which agents have access to the same strategy sets and the payoff structure is symmetric, implying that agents are interchangeable. Finally, we carry out an empirical illustration of the generalised method in several domains, illustrating the theory and evolutionary dynamics of several versions of the AlphaGo algorithm (symmetric), the dynamics of the Colonel Blotto game played by human players on Facebook (symmetric), the dynamics of several teams of players in the capture the flag game (symmetric), and an example of a meta-game in Leduc Poker (asymmetric), generated by the policy-space response oracle multi-agent learning algorithm

Distribution of Breeding Shorebirds on the Arctic Coastal Plain of Alaska

Available information on the distribution of breeding shorebirds across the Arctic Coastal Plain of Alaska is dated, fragmented, and limited in scope. Herein, we describe the distribution of 19 shorebird species from data gathered at 407 study plots between 1998 and 2004. This information was collected using a single-visit rapid area search technique during territory establishment and early incubation periods, a time when social displays and vocalizations make the birds highly detectable. We describe the presence or absence of each species, as well as overall numbers of species, providing a regional perspective on shorebird distribution. We compare and contrast our shorebird distribution maps to those of prior studies and describe prominent patterns of shorebird distribution. Our examination of how shorebird distribution and numbers of species varied both latitudinally and longitudinally across the Arctic Coastal Plain of Alaska indicated that most shorebird species occur more frequently in the Beaufort Coastal Plain ecoregion (i.e., closer to the coast) than in the Brooks Foothills ecoregion (i.e., farther inland). Furthermore, the occurrence of several species indicated substantial longitudinal directionality. Species richness at surveyed sites was highest in the western portion of the Beaufort Coastal Plain ecoregion. The broad-scale distribution information we present here is valuable for evaluating potential effects of human development and climate change on Arctic-breeding shorebird populations.Les renseignements qui existent en matière de répartition des oiseaux de rivage en reproduction sur la plaine côtière de l’Arctique en Alaska sont anciens, fragmentés et restreints. Ici, nous décrivons la répartition de 19 espèces d’oiseaux de rivage à partir de données recueillies à 407 lieux de recherche entre 1998 et 2004. Cette information a été recueillie grâce à une technique de recherche consistant en une seule visite rapide durant les périodes d’établissement du territoire et de début d’incubation, périodes pendant lesquelles les comportements sociaux et les vocalisations permettent de bien repérer les oiseaux. Nous décrivons la présence ou l’absence de chaque espèce, de même que le nombre général d’espèces, ce qui procure une perspective régionale de la répartition des oiseaux de rivage. Nous comparons et contrastons nos cartes de répartition des oiseaux de rivage à celles d’études antérieures, en plus de décrire les tendances les plus marquées en matière de répartition des oiseaux de rivage. Notre examen de la variation latitudinale et longitudinale en matière de répartition et de nombre d’espèces d’oiseaux de rivage à l’échelle de la plaine côtière arctique de l’Alaska nous a permis de constater que la plupart des espèces d’oiseaux de rivage se manifestaient plus souvent dans la région écologique de la plaine côtière de Beaufort (c’est-à-dire plus proche de la côte) que dans la région écologique des contreforts de Brooks (c’est-à-dire plus à l’intérieur des terres). Par ailleurs, l’occurrence de plusieurs espèces indiquait une directionalité longitudinale substantielle. La richesse des espèces aux sites à l’étude était à son meilleur dans la partie ouest de la région écologique de la plaine côtière de Beaufort. Les renseignements sur la répartition à grande échelle que nous présentons ici jouent un rôle dans l’évaluation des effets éventuels des travaux de mise en valeur par l’être humain et du changement climatique sur les populations d’oiseaux de rivage en reproduction de l’Arctique

Effects of geolocators on hatching success, return rates, breeding movements, and change in body mass in 16 species of Arctic-breeding shorebirds

Additional Authors: Bruce Casler; Maureen Christie; Jonathan T. Coleman; Jesse R. Conklin; Willow B. English; H. River Gates; Olivier Gilg; Marie-Andrée Giroux; Ken Gosbell; Chris Hassell; Jim Helmericks; Andrew Johnson; Borgný Katrínardóttir; Kari Koivula; Jean-Francois Lamarre; Johannes Lang; David B. Lank; Nicolas Lecomte; Joe Liebezeit; Vanessa Loverti; Laura McKinnon; Clive Minton; David Mizrahi; Erica Nol; Veli-Matti Pakanen; Johanna Perz; Ron Porter; Jennie Rausch; Jeroen Reneerkens; Nelli Rönkä; Sarah Saalfeld; Nathan Senner; Benoît Sittler; Paul A. Smith; Kristine Sowl; Audrey Taylor; David H. Ward; Stephen YezerinacCitation: Weiser, E.L., R.B. Lanctot, S.C. Brown, J.A. Alves, P.F. Battley, R. Bentzen, J. Bêty, M.A. Bishop, M. Boldenow, L. Bollache, B. Casler, M. Christie, J.T. Coleman, J.R. Conklin, W.B. English, H.R. Gates, O. Gilg, M.-A. Giroux, K. Gosbell, C. Hassell, J. Helmericks, A. Johnson, B. Katrínardóttir, K. Koivula, E. Kwon, J.-F. Lamarre, J. Lang, D.B. Lank, N. Lecomte, J. Liebezeit, V. Loverti, L. McKinnon, C. Minton, D. Mizrahi, E. Nol, V.-M. Pakanen, J. Perz, R. Porter, J. Rausch, J. Reneerkens, N. Rönkä, S. Saalfeld, N. Senner, B. Sittler, P.A. Smith, K. Sowl, A. Taylor, D.H. Ward, S. Yezerinac, and B.K. Sandercock. 2016. Effects of geolocators on hatching success, return rates, breeding movements and change in body mass in 16 species of Arctic-breeding shorebirds. Movement Ecology 4: art12. URL: http://movementecologyjournal.biomedcentral.com/articles/10.1186/s40462-016-0077-6Background: Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8–2.0 g total, representing 0.1–3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2–4 subspecies each for a total of 23 study taxa. Study species spanned a range of body sizes (26–1091 g) and eight genera, and were tagged at 23 breeding and eight nonbreeding sites. We compared breeding performance and return rates of birds with geolocators to control groups while controlling for potential confounding variables. Result: We detected negative effects of tags for three small-bodied species. Geolocators reduced annual return rates for two of 23 taxa: by 63 % for semipalmated sandpipers and by 43 % for the arcticola subspecies of dunlin. High resighting effort for geolocator birds could have masked additional negative effects. Geolocators were more likely to negatively affect return rates if the total mass of geolocators and color markers was 2.5–5.8 % of body mass than if tags were 0.3–2.3 % of body mass. Carrying a geolocator reduced nest success by 42 % for semipalmated sandpipers and tripled the probability of partial clutch failure in semipalmated and western sandpipers. Geolocators mounted perpendicular to the leg on a flag had stronger negative effects on nest success than geolocators mounted parallel to the leg on a band. However, parallel-band geolocators were more likely to reduce return rates and cause injuries to the leg. No effects of geolocators were found on breeding movements or changes in body mass. Among-site variation in geolocator effect size was high, suggesting that local factors were important. Conclusions: Negative effects of geolocators occurred only for three of the smallest species in our dataset, but were substantial when present. Future studies could mitigate impacts of tags by reducing protruding parts and minimizing use of additional markers. Investigators could maximize recovery of tags by strategically deploying geolocators on males, previously marked individuals, and successful breeders, though targeting subsets of a population could bias the resulting migratory movement data in some species

An upgrade of the magnetic diagnostic system of the DIII-D tokamak for non-axisymmetric measurements

The DIII-D tokamak magnetic diagnostic system [E. J. Strait, Rev. Sci. Instrum. 77, 023502 (2006)] has been upgraded to significantly expand the measurement of the plasma response to intrinsic and applied non-axisymmetric "3D" fields. The placement and design of 101 additional sensors allow resolution of toroidal mode numbers 1 ≤ n ≤ 3, and poloidal wavelengths smaller than MARS-F, IPEC, and VMEC magnetohydrodynamic model predictions. Small 3D perturbations, relative to the equilibrium field (10(-5) < δB/B0 < 10(-4)), require sub-millimeter fabrication and installation tolerances. This high precision is achieved using electrical discharge machined components, and alignment techniques employing rotary laser levels and a coordinate measurement machine. A 16-bit data acquisition system is used in conjunction with analog signal-processing to recover non-axisymmetric perturbations. Co-located radial and poloidal field measurements allow up to 14.2 cm spatial resolution of poloidal structures (plasma poloidal circumference is ~500 cm). The function of the new system is verified by comparing the rotating tearing mode structure, measured by 14 BP fluctuation sensors, with that measured by the upgraded B(R) saddle loop sensors after the mode locks to the vessel wall. The result is a nearly identical 2/1 helical eigenstructure in both cases.S. R. Haskey wishes to thank AINSE Ltd. for providing financial assistance

Predictors of invertebrate biomass and rate of advancement of invertebrate phenology across eight sites in the North American Arctic

Average annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers afecting invertebrate availability, we modeled the biomass of invertebrates captured in modifed Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confrmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively afected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey avail ability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level efects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.publishedVersio