scholarly journals Trappings of Success: Predator Removal for Duck Nest Survival in Alberta Parklands

Diversity ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 119
Author(s):  
Emily M. Blythe ◽  
Mark S. Boyce
Keyword(s):  
Prairie Pothole Region ◽  
Nest Survival ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Prairie Pothole ◽  
Mesopredator Release ◽  
Predator Removal ◽  
The North ◽  
Duck Species ◽  
And Control

Nest survival is most limited by nest predation, which often is increased by anthropogenic causes including habitat fragmentation, mesopredator release and predator subsidies. In mallards and other upland-nesting duck species in the North American prairies, the rate of nest survival is the vital rate most influential to population dynamics, with 15%–20% survival required for maintenance of stable populations. Predator removal during the nesting season has increased duck nest survival on township-sized (9324 ha) areas of agricultural ecosystems in eastern locations of the prairie pothole region (PPR). However, predator removal has not been evaluated in western parkland habitats of the PPR where three-dimensional structure of vegetation is considerably greater. During 2015–2017, we evaluated nest survival on control and predator-removal plots at two study areas in the parklands of central Alberta, Canada. In the second year of the study, we transposed predator removal to control for habitat effects. Estimates of 34-day nest survival did not significantly differ between trapped ( x ¯ = 20.9%, 95% CI = 13.2%–33.7%) and control ( x ¯ = 17.8%, 95% CI = 10.5%–30.0%) plots in any year. We do not recommend predator removal be continued in Alberta parklands due to its ineffectiveness at improving duck nest survival at the local scale.

3D Structure of Striations in the North Pacific

2021 ◽  
Author(s):  
YU ZHANG ◽  
YU PING GUAN ◽  
RUI XIN HUANG
Keyword(s):  
North Pacific ◽  
3D Structure ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Dimensional Structure ◽  
The North ◽  
Layer Analysis ◽  
Fluid Potential ◽  
The North Pacific

AbstractOcean striations are composed of alternating quasi-zonal band-like flows; this kind of organized structure of currents be found in all world’s oceans and seas. Previous studies have mainly been focused on the mechanisms of their generation and propagation. This study uses the spatial high-pass filtering to obtain the three-dimensional structure of ocean striations in the North Pacific in both the z-coordinate and σ-coordinate based on 10-yr averaged SODA3 data. First, we identify an ideal-fluid potential density domain where the striations are undisturbed by the surface forcing and boundary effects. Second, using the isopycnal layer analysis, we show that on isopycnal surfaces the orientations of striations nearly follow the potential vorticity (PV) contours, while in the meridional-vertical plane the central positions of striations are generally aligned with the latitude of zero gradient of the relative PV. Our analysis provides a simple dynamical interpretation and better understanding for the role of ocean striations.

scholarly journals Land Cover and Land Use Change in the US Prairie Pothole Region Using the USDA Cropland Data Layer

Land ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 166 ◽  
Author(s):  
Woubet G. Alemu ◽  
Geoffrey M. Henebry ◽  
Assefa M. Melesse
Keyword(s):  
Land Cover ◽  
North Dakota ◽  
Trend Analysis ◽  
Spring Wheat ◽  
Prairie Pothole Region ◽  
Prairie Pothole ◽  
The North ◽  
The Us ◽  
Data Layer ◽  
Pasture Area

The Prairie Pothole Region (PPR) is a biotically important region of grassland, wetland, and cropland that traverses the Canada-US border. Significant amounts of grasslands and wetlands within the PPR have been converted to croplands in recent years due to increasing demand for biofuels. We characterized land dynamics across the US portion of the PPR (US–PPR) using the USDA Crop Data Layer (CDL) for 2006–2018. We also conducted a comparative analysis between two epochs (1998–2007 & 2008–2017) of the CDL data time series in the North Dakotan portion of the US–PPR. The CDL revealed the western parts of the US–PPR have been dominated by grass/pasture, to the north it was spring wheat, to the east and southern half, soybeans dominated, and to the south it was corn (maize). Nonparametric trend analysis on the major crop and land cover types revealed statistically significant net decreases in the grass/pasture class between 2006 and 2018, which accounts for more than a quarter of grass/pasture area within the US–PPR. Other crops experiencing significant decreases included sunflower (-5%), winter wheat (-3%), spring wheat (-2%), and durum wheat (-1%). The combined coverage of corn and soybeans exhibited significant net increases in 23.5% of its cover; whereas, the individual significant net increases were 5% for corn and 11% for soybeans. Hotspots of increase in corn and soybeans were distributed across North and South Dakota. Other crop/land covers with huge significant increases include other hay/non-alfalfa (15%), and alfalfa (11%), which appear to be associated with the sharp increase in larger dairy operations, mostly in Minnesota. Wetland area increased 5% in the US–PPR, due to increased precipitation as well as inundation associated with Devils Lake in North Dakota. Hotspots of decreasing grass/pasture area were evident across the study area. Comparative trend analysis of two epochs (1998–2007 vs. 2008–2017) in North Dakota revealed that grass/pasture cover showed a negligible net trend (-0.3 %) between 1998 and 2007; whereas, there was a statistically significant decrease of more than 30% between 2008 and 2017. Combined coverage of corn and soybeans experienced statistically significant net increases in both epochs: 11% greater during 1998–2007 and 17% greater during 2008–2017. Recent sharp losses of grasslands and smaller wetlands combined the expansion of corn, soybeans, and alfalfa bode ill for wildlife habitat and require a re-examination of agricultural and energy policies that have encouraged these land transitions.

scholarly journals Time-lagged variation in pond density and primary productivity affects duck nest survival in the Prairie Pothole Region

2013 ◽  
Vol 23 (5) ◽  
pp. 1061-1074 ◽  
Author(s):  
Johann Walker ◽  
Jay J. Rotella ◽  
Scott E. Stephens ◽  
Mark S. Lindberg ◽  
James K. Ringelman ◽  
...  
Keyword(s):  
Primary Productivity ◽  
Prairie Pothole Region ◽  
Nest Survival ◽  
Prairie Pothole ◽  
Time Lagged

Site-selective C(sp3)-H Functionalizations Mediated by Hydrogen Atom Transfer Reactions via α-Amino/α-Amido Radicals

Synthesis ◽  
2021 ◽  
Author(s):  
Jaspreet Kaur ◽  
Joshua Philip Barham
Keyword(s):  
Hydrogen Atom ◽  
Three Dimensional ◽  
Hydrogen Atom Transfer ◽  
Dimensional Structure ◽  
Atom Transfer ◽  
Bond Polarity ◽  
Recent Developments ◽  
A Site ◽  
Site Selective ◽  
And Control

Amines and amides, as N-containing compounds, are ubiquitous in pharmaceutically active scaffolds, natural products, agrochemicals and peptides. Amides in nature bear key responsibility for three-dimensional structure, such as in proteins. Structural modifications to amines and amides, especially at their positions α- to N, bring about profound changes in biological activity oftentimes leading to more desirable pharmacological profiles of small molecule drugs. A number of recent developments in synthetic methodology for the functionalizations of amines and amides omit the need of directing groups or pre-functionalizations, achieving direct activation of the otherwise benign C(sp3)-H bond. Among these, hydrogen atom transfer (HAT) has proven a very powerful platform for the selective activation of amines and amides to their α-amino and α-amido radicals, which can then be employed to furnish C-C and C-X (X=heteroatom) bonds. The ability to both form these radicals and control their reactivity in a site-selective manner is of utmost importance for such chemistries to witness applications in late-stage functionalization. Therefore, this review captures contemporary HAT strategies to realize chemo- and regioselective amine and amide α-C(sp3)-H functionalization, based on bond strength, bond polarity, reversible HAT equilibria, traceless electrostatic directing auxiliaries and steric effects of in situ-generated HAT agents.

The Statistics and Structure of Subseasonal Midlatitude Variability in NASA GSFC GCMs

2005 ◽  
Vol 18 (16) ◽  
pp. 3294-3316 ◽  
Author(s):  
Dennis P. Robinson ◽  
Robert X. Black
Keyword(s):  
Three Dimensional ◽  
Storm Track ◽  
Storm Tracks ◽  
Dimensional Structure ◽  
Mean Flow ◽  
Weather Regimes ◽  
Three Dimensional Structure ◽  
Dynamical Characteristics ◽  
The North ◽  
Synoptic Eddies

Abstract A comprehensive analysis of midlatitude intraseasonal variability in extended integrations of NASA GSFC general circulation models (GCMs) is conducted. This is approached by performing detailed intercomparisons of the representation of the storm tracks and anomalous weather regimes occurring during wintertime in the Atmospheric Model Intercomparison Project (AMIP)-type simulations of both the NASA–NCAR and a version of the Aries model used in NASA’s Seasonal-to-Interannual Prediction Project (NSIPP) model. The model-simulated statistics, three-dimensional structure, and dynamical characteristics of these phenomena are diagnosed and directly compared to parallel observational analyses derived from NCEP–NCAR reanalyses. A qualitatively good representation of the vertical structure of intraseasonal eddy kinetic energy (EKE) is provided by both models with maximum values of EKE occurring near 300 hPa. The main model shortcoming is an underestimation of EKE in the upper troposphere, especially for synoptic eddies in the NSIPP model. Nonetheless, both models provide a reasonable representation of the three-dimensional structure and dynamical characteristics of synoptic eddies. Discrepancies in the storm-track structures simulated by the models include an anomalous local minimum over the eastern Pacific basin. However, both GCMs faithfully reproduce the observed Pacific midwinter storm-track suppression. Interestingly, the NSIPP model also produces a midwinter suppression feature over the Atlantic storm track in association with the anomalously strong upper-level jet stream simulated by NSIPP in this region. The regional distribution of anomalous weather regime events is well simulated by the models. However, substantial structural differences exist between observed and simulated events over the North Pacific region. In comparison to observations, model events are horizontally more isotropic, have stronger westward vertical tilts, and are more strongly driven by baroclinic dynamics. The structure and dynamics of anomalous weather regimes occurring over the North Atlantic region are qualitatively better represented by the models. The authors suggest that model deficiencies in representing the zonally asymmetric climatological-mean flow field (particularly the magnitude and structure of the Pacific and Atlantic jet streams) help contribute to model shortcomings in (i) the strength and seasonal variability of the storm tracks and (ii) dynamical distinctions in the maintenance of large-scale weather regimes.

scholarly journals Climate trends of the North American prairie pothole region 1906–2000

2009 ◽  
Vol 93 (1-2) ◽  
pp. 243-267 ◽  
Author(s):  
Bruce Millett ◽  
W. Carter Johnson ◽  
Glenn Guntenspergen
Keyword(s):  
North American ◽  
Prairie Pothole Region ◽  
Prairie Pothole ◽  
Climate Trends ◽  
The North ◽  
North American Prairie

scholarly journals Three-Dimensional Structure and Temporal Evolution of Submesoscale Thermohaline Intrusions in the North Pacific Subtropical Frontal Zone

2010 ◽  
Vol 40 (8) ◽  
pp. 1669-1689 ◽  
Author(s):  
A. Y. Shcherbina ◽  
M. C. Gregg ◽  
M. H. Alford ◽  
R. R. Harcourt
Keyword(s):  
North Pacific ◽  
Frontal Zone ◽  
Opposite Sign ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Structure ◽  
Subtropical Front ◽  
The North ◽  
Lateral Advection ◽  
The North Pacific

Abstract Four instances of persistent intrusive deformation of the North Pacific Subtropical Front were tagged individually by a Lagrangian float and tracked for several days. Each feature was mapped in three dimensions using repeat towed observations referenced to the float. Isohaline surface deformations in the frontal zone included sheetlike folds elongated in the alongfront direction and narrow tongues extending across the front. All deformations appeared as protrusions of relatively cold, and fresh, water across the front. No corresponding features of the opposite sign or isolated lenslike structures were observed. The sheets were O(10 m) thick, protruded about 10 km into the warm saline side of the front, and were coherent for 10–30 km along the front. Having about the same thickness and cross-frontal extent as the sheets, tongues extended less than 5 km along the front. All of the intrusions persisted as long as they were followed, several days to one week. Their structures evolved on both inertial (23 h) and subinertial (∼10 days) time scales in response to differential lateral advection. The water mass surrounding the intrusions participated in gradual anticyclonic rotation as a part of a mesoscale meander of the subtropical front. The intrusions may be interpreted as a manifestation of three-dimensional submesoscale turbulence of the frontal zone, driven by the mesoscale. Absence of large features of the opposite sign may be indicative of the asymmetry of the underlying dynamics.

Three-Dimensional Interactive Simulation of Anschütz Gyrocompass Based on VRML

2011 ◽  
Vol 317-319 ◽  
pp. 2278-2283
Author(s):  
Jian Hua Wu ◽  
Xun Fang ◽  
Hao Li
Keyword(s):  
Virtual Reality ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Modeling Language ◽  
Interactive Simulation ◽  
Virtual Reality Environment ◽  
Source Codes ◽  
The North ◽  
Virtual Reality Modeling Language ◽  
Realization Process

Gyrocompass is an important instrument which provides course to vessels, but its complex three-dimensional structure and principle of pointing towards the North is a bottleneck of studying gyrocompass. The master compass of Anschütz 4 gyrocompass are simulated by virtual reality modeling language VRML, so that using three-dimensional interactive to show the structure of the gyrocompass and the work principle is implemented and learners will have a direct cognition to each part of the gyrocompass and its work principle. The realization process of simulation in the virtual reality environment is described in detail and the relevant source codes is given.

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