scholarly journals Fat, weather, and date affect migratory songbirds’ departure decisions, routes, and time it takes to cross the Gulf of Mexico

2015 ◽  
Vol 112 (46) ◽  
pp. E6331-E6338 ◽  
Author(s):  
Jill L. Deppe ◽  
Michael P. Ward ◽  
Rachel T. Bolus ◽  
Robert H. Diehl ◽  
Antonio Celis-Murillo ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Radio Telemetry ◽  
Open Water ◽  
Probability Of Detection ◽  
Lower Probability ◽  
Weather Patterns ◽  
Fat Reserves ◽  
Migratory Songbirds ◽  
Departure Decisions ◽  
Species Specific

Approximately two thirds of migratory songbirds in eastern North America negotiate the Gulf of Mexico (GOM), where inclement weather coupled with no refueling or resting opportunities can be lethal. However, decisions made when navigating such features and their consequences remain largely unknown due to technological limitations of tracking small animals over large areas. We used automated radio telemetry to track three songbird species (Red-eyed Vireo, Swainson’s Thrush, Wood Thrush) from coastal Alabama to the northern Yucatan Peninsula (YP) during fall migration. Detecting songbirds after crossing ∼1,000 km of open water allowed us to examine intrinsic (age, wing length, fat) and extrinsic (weather, date) variables shaping departure decisions, arrival at the YP, and crossing times. Large fat reserves and low humidity, indicative of beneficial synoptic weather patterns, favored southward departure across the Gulf. Individuals detected in the YP departed with large fat reserves and later in the fall with profitable winds, and flight durations (mean = 22.4 h) were positively related to wind profit. Age was not related to departure behavior, arrival, or travel time. However, vireos negotiated the GOM differently than thrushes, including different departure decisions, lower probability of detection in the YP, and longer crossing times. Defense of winter territories by thrushes but not vireos and species-specific foraging habits may explain the divergent migratory behaviors. Fat reserves appear extremely important to departure decisions and arrival in the YP. As habitat along the GOM is degraded, birds may be limited in their ability to acquire fat to cross the Gulf.

scholarly journals Analysis of Low Probability of Detection Capability for Chaotic Standard Map-Based FH-OFDMA System

2021 ◽  
Vol 11 (5) ◽  
pp. 2198
Author(s):  
Junwoo Jung ◽  
Jaesung Lim ◽  
Sungyeol Park ◽  
Haengik Kang ◽  
Seungbok Kwon
Keyword(s):  
Detection Probability ◽  
Probability Of Detection ◽  
Lower Probability ◽  
Symbol Sequence ◽  
Ofdma System ◽  
Standard Map ◽  
Detection Probabilities ◽  
Low Probability ◽  
Transmitted Symbol ◽  
Basic Symbol

A frequency hopping orthogonal frequency division multiple access (FH-OFDMA) can provide low probability of detection (LPD) and anti-jamming capabilities to users against adversary detectors. To obtain an extreme LPD capability that cannot be provided by the basic symbol-by-symbol (SBS)-based FH pattern, we proposed two FH patterns, namely chaotic standard map (CSM) and cat map for FH-OFDMA systems. In our previous work, through analysis of complexity to regenerate the transmitted symbol sequence, at the point of adversary detectors, we found that the CSM had a lower probability of intercept than the cat map and SBS. It is possible when a detector already knows symbol and frame structures, and the detector has been synchronized to the FH-OFDMA system. Unlike the previous work, here, we analyze whether the CSM provides greater LPD capability than the cat map and SBS by detection probability using spectrum sensing technique. We analyze the detection probability of the CSM and provide detection probabilities of the cat map and SBS compared to the CSM. Based on our analysis of the detection probability and numerical results, it is evident that the CSM provides greater LPD capability than both the cat map and SBS-based FH-OFDMA systems.

scholarly journals Anurans in a Subarctic Tundra Landscape Near Cape Churchill, Manitoba

2008 ◽  
Vol 122 (2) ◽  
pp. 129 ◽  
Author(s):  
Matthew E. Reiter ◽  
Clint W. Boal ◽  
David E. Andersen
Keyword(s):  
Boreal Forest ◽  
Forest Edge ◽  
Habitat Associations ◽  
Probability Of Detection ◽  
Spatial And Temporal Variation ◽  
Wood Frogs ◽  
Lithobates Sylvaticus ◽  
Landscape Types ◽  
Species Specific ◽  
Monitoring Protocols

Distribution, abundance, and habitat relationships of anurans inhabiting subarctic regions are poorly understood, and anuran monitoring protocols developed for temperate regions may not be applicable across large roadless areas of northern landscapes. In addition, arctic and subarctic regions of North America are predicted to experience changes in climate and, in some areas, are experiencing habitat alteration due to high rates of herbivory by breeding and migrating waterfowl. To better understand subarctic anuran abundance, distribution, and habitat associations, we conducted anuran calling surveys in the Cape Churchill region of Wapusk National Park, Manitoba, Canada, in 2004 and 2005. We conducted surveys along ~1-km transects distributed across three landscape types (coastal tundra, interior sedge meadow–tundra, and boreal forest–tundra interface) to estimate densities and probabilities of detection of Boreal Chorus Frogs (Pseudacris maculata) and Wood Frogs (Lithobates sylvaticus). We detected a Wood Frog or Boreal Chorus Frog on 22 (87%) of 26 transects surveyed, but probability of detection varied between years and species and among landscape types. Estimated densities of both species increased from the coastal zone inland toward the boreal forest edge. Our results suggest anurans occur across all three landscape types in our study area, but that species-specific spatial patterns exist in their abundances. Considerations for both spatial and temporal variation in abundance and detection probability need to be incorporated into surveys and monitoring programs for subarctic anurans.

Influence of Open Water Bodies on the Modeling of Summertime Convection over the Canadian Prairies

2017 ◽  
Vol 18 (6) ◽  
pp. 1583-1594
Author(s):  
Deepti Joshi ◽  
Marco Carrera ◽  
Stephane Bélair ◽  
Sylvie Leroyer
Keyword(s):  
Convective Available Potential Energy ◽  
Open Water ◽  
Water Bodies ◽  
Convective Precipitation ◽  
Precipitation Event ◽  
Canadian Prairies ◽  
Water Fraction ◽  
Weather Patterns ◽  
Global Environmental ◽  
Land Water

Abstract There are numerous water features on the Canadian landscapes that are not monitored. Specifically, there are water bodies over the prairies and Canadian shield regions of North America that are ephemeral in nature and could have a significant influence on convective storm generation and local weather patterns through turbulent exchanges of sensible and latent heat between the land and the atmosphere. In this study a series of numerical experiments is performed with Environment and Climate Change Canada’s Global Environmental Multiscale (GEM) model at 2.5-km grid spacing to examine the sensitivity of the atmospheric boundary layer and the resulting precipitation to the presence of open water bodies. Operationally, the land–water fraction in GEM is specified by means of static geophysical databases that do not change with time. Uncertainty is introduced in this study into this land–water fraction and the sensitivity of the resulting precipitation is quantified for a convective precipitation event occurring over the Canadian Prairies in the summer of 2014. The results indicate that with an increase in open water bodies, accumulated precipitation, peak precipitation amounts, and intensities decrease. Moreover, shifts are seen in times of peak for both precipitation amounts and intensities, in the order of increasing wetness. Additionally, with an increase in open water bodies, convective available potential energy decreases and convective inhibition increases, indicating suppression of forcing for convective precipitation.

Global compound floods from precipitation and storm surge: Hazards and the roles of cyclones

2021 ◽  
pp. 1-55
Author(s):  
Yangchen Lai ◽  
Jianfeng Li ◽  
Xihui Gu ◽  
Cancan Liu ◽  
Yongqin David Chen
Keyword(s):  
Storm Surges ◽  
Precipitable Water ◽  
Weather Conditions ◽  
Northern Europe ◽  
Lower Probability ◽  
Flood Hazards ◽  
Weather Patterns ◽  
Joint Return ◽  
Marginal Values ◽  
The Impact

AbstractDuring simultaneous or successive occurrences of precipitation and storm surges, the interplay of the two types of extremes can exacerbate the impact to a greater extent than either of them in isolation. The compound flood hazards from precipitation and storm surges vary across regions of the world because of the various weather conditions. By analyzing in-situ observations of precipitation and storm surges across the globe, we found that the return periods of compound floods with marginal values exceeding the 98.5th percentile (i.e., equivalent to a joint return period of 12 years if the marginal variables are independent) are < 2 years in most areas, while those in northern Europe are > 8 years due to weaker dependence. Our quantitative assessment shows that cyclones (i.e., tropical cyclones (TCs) and extratropical cyclones (ETCs)) are the major triggers of compound floods. More than 80% of compound floods in East Asia and > 50% of those in the Gulf of Mexico and northern Australia are associated with TCs, while in northern Europe and the higher latitude coast of North America, ETCs contribute to the majority of compound floods (i.e., 80%). Weather patterns characterized by deep low pressure, cyclonic wind, and abundant precipitable water content are conducive to the occurrence of compound floods. Extreme precipitation and extreme storm surges over Europe tend to occur in different months, which explains the relatively lower probability of compound floods in Europe. The comprehensive hazard assessment of global compound floods in this study serves as an important reference for flood risk management in coastal regions across the globe.

scholarly journals Arctic Fog Detection Using Infrared Spectral Measurements

2019 ◽  
Vol 36 (8) ◽  
pp. 1643-1656
Author(s):  
Li Yi ◽  
King-Fai Li ◽  
Xianyao Chen ◽  
Ka-Kit Tung
Keyword(s):  
Sea Ice ◽  
Chukchi Sea ◽  
Open Water ◽  
Detection Algorithm ◽  
Probability Of Detection ◽  
Satellite Observations ◽  
The Arctic ◽  
Water Surface Area ◽  
Infrared Spectral ◽  
Fog Detection

AbstractThe rapid increase in open-water surface area in the Arctic, resulting from sea ice melting during the summer likely as a result of global warming, may lead to an increase in fog [defined as a cloud with a base height below 1000 ft (~304 m)], which may imperil ships and small aircraft transportation in the region. There is a need for monitoring fog formation over the Arctic. Given that ground-based observations of fog over Arctic open water are very sparse, satellite observations may become the most effective way for Arctic fog monitoring. We developed a fog detection algorithm using the temperature difference between the cloud top and the surface, called ∂T in this work. A fog event is said to be detected if ∂T is greater than a threshold, which is typically between −6 and −12 K, depending on the time of the day (day or night) and the surface types (open water or sea ice). We applied this method to the coastal regions of Chukchi Sea and Beaufort Sea near Barrow, Alaska (now known as Utqiaġvik), during the months of March–October. Training with satellite observations between 2007 and 2014 over this region, the ∂T method can detect Arctic fog with an optimal probability of detection (POD) between 74% and 90% and false alarm rate (FAR) between 5% and 17%. These statistics are validated with data between 2015 and 2016 and are shown to be robust from one subperiod to another.

The ecology of bats in south-east Australian forests and potential impacts of forestry practices: a review

1995 ◽  
Vol 2 (4) ◽  
pp. 363 ◽  
Author(s):  
Bradley S. Law
Keyword(s):  
Species Richness ◽  
Radio Telemetry ◽  
Habitat Preferences ◽  
Structural Complexity ◽  
Current Evidence ◽  
Mature Trees ◽  
Long Distance ◽  
Forestry Practices ◽  
High Conservation ◽  
Species Specific

Bats are important contributors to Australia's mammal diversity and are ecologically diverse, feeding on insects, fish, small vertebrates, nectar, pollen and fruit. As such they are likely to play key ecological roles as regulators of invertebrate populations and pollinators of forests. Although somewhat contradictory, current evidence suggest that logging impacts on the species richness and activity of insectivorous bats when forest structural complexity and the number of available roosting hollows are reduced. Inconsistent results concerning impact on species richness stem from methodological problems with bat surveys. "Rare" species are often recorded in low numbers, preventing habitat preferences and disturbance impacts from being determined. Radio-telemetry has demonstrated that roosts in hollows of mature trees are a critical resource for many species of bats due to species specific requirements. However, it is not yet possible to state whether bat populations are directly limited by the availability of hollows in areas where a mosaic of logged and unlogged forest exists. Although data on foraging areas are extremely limited, some species appear to be flexible, capable of flying across open areas and exploiting those rich in invertebrates. Some species (e.g., Vespadelus) show a high degree of site attachment, possibly indicating a susceptibility to logging, however, the extent of site fidelity for most species is unknown. As pollinators, megachiropteran bats are likely to play a key role in maintaining the genetic diversity currently present in eucalypts by facilitating long-distance movement of pollen. Areas that are productive in nectar and pollen have a high conservation value for these bats and many other nectarivores, however, the age at which important nectar-producing trees flower is generally not known. The extent to which wildlife prescriptions, such as habitat trees and mosaics of small reserves, mitigate these impacts on bat species requires urgent research.

Novel epigenetic age estimation in wild-caught Gulf of Mexico reef fishes

2021 ◽  
Author(s):  
D. Nick Weber ◽  
Andrew T. Fields ◽  
William F. Patterson ◽  
Beverly K. Barnett ◽  
Christopher M. Hollenbeck ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Gulf Of Mexico ◽  
Age Estimation ◽  
Reef Fishes ◽  
Lutjanus Campechanus ◽  
Cpg Sites ◽  
Epigenetic Aging ◽  
Epigenetic Age ◽  
Red Grouper ◽  
Species Specific

Cutting-edge DNA methylation-based epigenetic aging techniques were applied to Gulf of Mexico northern red snapper (Lutjanus campechanus; n = 10; 1–26 years old) and red grouper (Epinephelus morio; n = 10; 2–14 years old). Bisulfite-converted restriction site-associated DNA sequencing was used to identify CpG sites (cytosines followed by guanines) that exhibit age-correlated DNA methylation, and species-specific epigenetic clocks developed from 100s of CpG sites in each species showed strong agreements between predicted and otolith-derived ages (r2 > 0.99 for both species). Results suggest epigenetic age estimation could provide an accurate and efficient approach to mass-aging fishes in a non-invasive manner.

Does a better grade of tumour occurring in women under hormone replacement therapy compensate for their lower probability of detection by screening mammography

2002 ◽  
Vol 9 (2) ◽  
pp. 70-73 ◽  
Author(s):  
J. Estève ◽  
B. Séradour ◽  
J. Jacquemier ◽  
L. Remontet
Keyword(s):  
Breast Cancer ◽  
Hormone Replacement Therapy ◽  
Replacement Therapy ◽  
Hormone Replacement ◽  
Screening Mammography ◽  
Probability Of Detection ◽  
Lower Probability ◽  
Lower Grade ◽  
Breast Cancers ◽  
Mode Of Detection

OBJECTIVE: To compare the prognostic factor of breast cancer survival between breast cancer diagnosed in subjects receiving hormone replacement therapy (HRT) before diagnosis to those without such a therapy. Subjects and methods: All breast cancers diagnosed between 1993 and 2000 within the breast cancer screening programme in Bouches du Rhône (France) were analysed for size, node status, and grade according to use, or not, of HRT. Univariate and multivariate analyses were carried out taking into account age, density of the breast, and mode of detection. RESULTS: The breast tumours diagnosed among HRT users had a lower grade whatever the mode of detection. The proportion of node positive tumours was identical in the two groups after adjustment for age. The smaller size of the tumours among HRT users is partly explained by the lower grade of these tumours Conclusion: Although tumours occurring in HRT users have a lower chance of being detected by screening, their prognostic factors, especially the grade of the tumour, are better than in non-users. More work is needed to find which part of this advantage is attributable to better surveillance of women treated with HRT

scholarly journals Time budget patterns and complementary use of a Mediterranean wetland (Tonga, North-east Algeria) by migrant and resident waterbirds

2016 ◽  
Vol 86 (1) ◽  
pp. 55 ◽  
Author(s):  
Elafri Ali ◽  
Halassi Ismahan ◽  
Houhamdi Moussa
Keyword(s):  
Coastal Wetlands ◽  
Time Budget ◽  
Quantitative Description ◽  
Late Summer ◽  
Open Water ◽  
Feeding Time ◽  
Time Budgets ◽  
North East ◽  
Species Specific ◽  
Open Water Body

We carried out a quantitative description of the use of a Mediterranean wetland (Tonga, North-east Algeria) by 22 waterbirds species (11 residents and 11 Palaearctic migrants) during late summer-wintering period, also analyzing their species-specific diurnal time budgets and the main related features of the landscape. The analyses of similarity in time budgets across birds (Hierarchal Cluster Analysis) showed four clusters of species associated with four major activities: day time mostly feeding (11 species), sleeping (6), swimming (3) and resting (2). Residents (Herons and Rails) showed a higher feeding time when compared to migrants (diving ducks, Gulls and Cormorants). From late summer to winter the time budget activity change in migrants; in contrast residents behave uniformly among daytime and at the course of the season. The use of this natural wetland in a complementary way by a high number of waterbirds (residents and migrants), is principally promoted by the existing of numerous habitat types. We found that 3 main ecological units, open water body, mudflats, and flooded meadows were the most utilized as foraging habitats among grebes, rails, ducks, gulls, and herons. In contrast, floating-leafed vegetation, and tall emergent vegetation were the commonest habitat categories used in resting activities especially by cormorants and herons. Data on behaviour requirements of these waterbirds can be used for conservation and correct management of this and other Mediterranean coastal wetlands.

Erratic occurrence of anostracans in a temporary pond: colonization and extinction or adaptation to variations in annual weather?

1983 ◽  
Vol 61 (7) ◽  
pp. 1492-1498 ◽  
Author(s):  
David B. Donald
Keyword(s):  
Species Composition ◽  
The Other ◽  
Temporary Pond ◽  
Review Of Literature ◽  
Weather Patterns ◽  
Species Specific ◽  
Occurrence Patterns ◽  
Branchinecta Paludosa ◽  
Critical Times

Five species of Anostraca (Branchinecta paludosa (O.F.M.), Branchinecta lindahli Packard, Eubranchipus bundyi Forbes, Eubranchipus intricatus Hartland-Rowe, and Eubranchipus ornatus Holmes) inhabited a temporary pond near Calgary, Alberta. During a 14-year study of this pond, occurrence and species composition of anostracans changed almost every year. In most years only one to three species were common or abundant, and the other species were either absent or rare. Four of the five species were dominant in at least 1 year. A review of literature on anostracans and analyses of annual weather patterns at Calgary were carried out in order to determine the cause of these erratic occurrence patterns and changes in species composition. For Eubranchipus bundyi, Branchinecta lindahli, and possibly Eubranchipus intricatus, the cause was probably due to long-term viability of eggs in association with species specific requirements of the embryo for certain quantities of precipitation at critical times of the year. It is suggested that when these precipitation requirements were ideal, hatching was substantial. For two other species, Branchinecta paludosa and Eubranchipus ornatus, erratic occurrence patterns could be explained by either the above or by a colonization–extinction hypothesis.

Sign in / Sign up

Export Citation Format

Share Document