scholarly journals Heat dissipation capacity influences reproductive performance in an aerial insectivore

2019 ◽  
Author(s):  
Simon Tapper ◽  
Joseph J. Nocera ◽  
Gary Burness
Keyword(s):  
Heat Dissipation ◽  
Population Decline ◽  
Experimental Treatment ◽  
Extreme Weather Events ◽  
Weather Patterns ◽  
Thermal Window ◽  
Aerial Insectivore ◽  
Maternal Provisioning ◽  
Aerial Insectivores ◽  
Breeding Seasons

AbstractClimatic warming will likely increase the frequency of extreme weather events, which may reduce an individual’s capacity for sustained activity due to thermal limits. We tested whether the risk of overheating may limit parental provisioning of an aerial insectivorous bird in population decline. For many seasonally breeding birds, parents are thought to operate close to an energetic ceiling during the 2-3 week chick-rearing period. The factors determining the ceiling remain unknown, although it may be set by an individual’s capacity to dissipate body heat (the heat dissipation limitation hypothesis). To test this hypothesis, over two breeding seasons we experimentally trimmed the ventral feathers of female tree swallows (Tachycineta bicolor) to provide a thermal window. We then monitored maternal provisioning rates, nestling growth rates, and fledging success. We found the effect of our experimental treatment was context-dependent and varied with environmental conditions. Females with trimmed plumage fed their nestlings at higher rates than controls when conditions were hot and non-windy, but the reverse was true under cool and windy conditions. On average, nestlings of trimmed females were heavier than controls, and had a higher probability of fledging. We suggest that removal of a thermal constraint allowed females to increase provisioning rates, but additionally provided nestlings with a thermal advantage via increased heat transfer during maternal brooding. Our data provide partial support for the heat dissipation limitation hypothesis, and suggest that depending on weather patterns, heat dissipation capacity can influence reproductive success in aerial insectivores.

Influence of rainfall on population dynamics and survival of a threatened rodent (Pseudomys novaehollandiae) under a drying climate in coastal woodlands of south-eastern Australia

2017 ◽  
Vol 65 (1) ◽  
pp. 60 ◽  
Author(s):  
Mandy Lock ◽  
Barbara A. Wilson
Keyword(s):  
Population Dynamics ◽  
Population Decline ◽  
Resource Depletion ◽  
Mammal Species ◽  
Eastern Australia ◽  
Apparent Decrease ◽  
Mediterranean Systems ◽  
Precipitous Decline ◽  
Breeding Seasons ◽  
Successional Vegetation

In Mediterranean systems, such as south-east Australia, predictions of climate change including lower rainfall and extended drought, threaten vulnerable mammal species. We investigated the relationship between rainfall and population dynamics for a native rodent at risk of extinction, the New Holland mouse (Pseudomys novaehollandiae). In the eastern Otways, the species was significantly influenced by rainfall, exhibiting a population irruption (15–20 individuals ha–1) following six years of above-average rainfall and a precipitous decline to site extinction during subsequent drought. The decline was predominantly related to loss of adults before and during breeding seasons, together with an apparent decrease in juvenile survival. Population abundance was positively correlated with a rainfall lag of 0–9 months. We propose that the response of this omnivore to high rainfall was mediated through increased productivity and that rainfall decline resulted in resource depletion and population decline. Under a drying climate the direct impacts of rainfall decline will continue. However management of other threats may increase the species’ resilience. Burning to provide optimal successional vegetation, protection of refugia, and predator control are priorities. However, burning should be avoided during drought, as the likelihood of local extinctions is substantial.

scholarly journals Evidence linking rapid Arctic warming to mid-latitude weather patterns

2015 ◽  
Vol 373 (2045) ◽  
pp. 20140170 ◽  
Author(s):  
Jennifer Francis ◽  
Natasa Skific
Keyword(s):  
Northern Hemisphere ◽  
Weather Conditions ◽  
Extreme Weather Events ◽  
Jet Stream ◽  
Self Organizing Maps ◽  
Arctic Warming ◽  
Scientific Debate ◽  
Weather Patterns ◽  
Enhanced Sensitivity ◽  
Active Research

The effects of rapid Arctic warming and ice loss on weather patterns in the Northern Hemisphere is a topic of active research, lively scientific debate and high societal impact. The emergence of Arctic amplification—the enhanced sensitivity of high-latitude temperature to global warming—in only the last 10–20 years presents a challenge to identifying statistically robust atmospheric responses using observations. Several recent studies have proposed and demonstrated new mechanisms by which the changing Arctic may be affecting weather patterns in mid-latitudes, and these linkages differ fundamentally from tropics/jet-stream interactions through the transfer of wave energy. In this study, new metrics and evidence are presented that suggest disproportionate Arctic warming—and resulting weakening of the poleward temperature gradient—is causing the Northern Hemisphere circulation to assume a more meridional character (i.e. wavier), although not uniformly in space or by season, and that highly amplified jet-stream patterns are occurring more frequently. Further analysis based on self-organizing maps supports this finding. These changes in circulation are expected to lead to persistent weather patterns that are known to cause extreme weather events. As emissions of greenhouse gases continue unabated, therefore, the continued amplification of Arctic warming should favour an increased occurrence of extreme events caused by prolonged weather conditions.

scholarly journals Omega-3 long-chain polyunsaturated fatty acids support aerial insectivore performance more than food quantity

2016 ◽  
Vol 113 (39) ◽  
pp. 10920-10925 ◽  
Author(s):  
Cornelia W. Twining ◽  
J. Thomas Brenna ◽  
Peter Lawrence ◽  
J. Ryan Shipley ◽  
Troy N. Tollefson ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Acid Composition ◽  
Tree Swallow ◽  
Omega 3 ◽  
Food Quantity ◽  
Aerial Insectivore ◽  
Aerial Insectivores ◽  
Terrestrial Insects ◽  
Long Chain

Once-abundant aerial insectivores, such as the Tree Swallow (Tachycineta bicolor), have declined steadily in the past several decades, making it imperative to understand all aspects of their ecology. Aerial insectivores forage on a mixture of aquatic and terrestrial insects that differ in fatty acid composition, specifically long-chain omega-3 polyunsaturated fatty acid (LCPUFA) content. Aquatic insects contain high levels of both LCPUFA and their precursor omega-3 PUFA, alpha-linolenic acid (ALA), whereas terrestrial insects contain much lower levels of both. We manipulated both the quantity and quality of food for Tree Swallow chicks in a full factorial design. Diets were either high-LCPUFA or low in LCPUFA but high in ALA, allowing us to separate the effects of direct LCPUFA in diet from the ability of Tree Swallows to convert their precursor, ALA, into LCPUFA. We found that fatty acid composition was more important for Tree Swallow chick performance than food quantity. On high-LCPUFA diets, chicks grew faster, were in better condition, and had greater immunocompetence and lower basal metabolic rates compared with chicks on both low LCPUFA diets. Increasing the quantity of high-LCPUFA diets resulted in improvements to all metrics of performance while increasing the quantity of low-LCPUFA diets only resulted in greater immunocompetence and lower metabolic rates. Chicks preferentially retained LCPUFA in brain and muscle when both food quantity and LCPUFA were limited. Our work suggests that fatty acid composition is an important dimension of aerial insectivore nutritional ecology and reinforces the importance of high-quality aquatic habitat for these declining birds.

The Impact of Climate Change in the Modern Enterprise

2011 ◽  
Vol 2 (3) ◽  
pp. 26-35 ◽  
Author(s):  
Anastasios Danos ◽  
Konstantina Boulouta
Keyword(s):  
Climate Change ◽  
Critical Infrastructure ◽  
Extreme Weather Events ◽  
Sea Levels ◽  
Weather Patterns ◽  
Changing Climate ◽  
Modern Enterprise ◽  
The World ◽  
Rising Sea Levels ◽  
The Impact

This article analyses the profound and rapid climate changes that have taken place worldwide in the past two decades and their effects on modern enterprise. Reducing greenhouse gas emissions and developing strategies to adapt to and counterbalance future impacts of climate change sustainably are among the most pressing needs of the world today. Global temperatures are predicted to continue rising, bringing changes in weather patterns, rising sea levels, and increased frequency and intensity of extreme weather events. Such climatic events can have a major impact on households, businesses, critical infrastructure and vulnerable sections of society, as well as having a major economic impact. Therefore, society must prepare to cope with living in a changing climate. The effects of a changing climate have considerable impacts on modern enterprises. In some parts of the world, these impacts are increasingly becoming evident.

Evidence for multiple drivers of aerial insectivore declines in North America

The Condor ◽  
2019 ◽  
Vol 121 (2) ◽  
Author(s):  
Kimberly J Spiller ◽  
Randy Dettmers
Keyword(s):  
North America ◽  
Habitat Loss ◽  
Prey Abundance ◽  
Research Progress ◽  
Current Evidence ◽  
High Quality ◽  
Prey Quality ◽  
Aerial Insectivore ◽  
Starting Point ◽  
Aerial Insectivores

Abstract Aerial insectivores (birds that forage on aerial insects) have experienced significant population declines in North America. Numerous hypotheses have been proposed for these declines, but current evidence suggests multiple factors could be operating in combination during their annual migratory cycles between breeding and nonbreeding areas. Potential drivers include decreased prey abundance, direct or indirect impacts of environmental contaminants, habitat loss, phenological changes due to warming climate, and conditions on migratory stopover or wintering grounds. While no single threat appears to be the cause of aerial insectivore declines, existing evidence suggests that several of these factors could be contributing to the declines at different times in the annual lifecycle. Breeding productivity for most of these species does not appear to be limited by overall prey abundance, contaminants, or habitat loss, which suggests that similar issues on nonbreeding grounds or carryover effects could play important roles. However, a better understanding of the importance of prey quality throughout the lifecycle is critically needed. Based on current evidence, we propose that changes in availability of high-quality prey, with variability across breeding and nonbreeding grounds, reduce various combinations of fledging success, post-fledging survival, and nonbreeding season body condition of aerial insectivores, resulting in species and geographic differences in population trends. We encourage others to use this hypothesis as a starting point to test specific mechanisms by which availability of high-quality prey influences demographic parameters. We suggest that future research focus on defining prey quality, monitoring insect abundance in conjunction with birds, comparing demographic models across local populations experiencing different population growth rates, and using tracking technology to document important migratory and nonbreeding areas. Considerable research progress already has been made, but additional research is needed to better understand the complex web of potential causes driving aerial insectivore declines.

scholarly journals Heat stress during the luteal phase decreases luteal size but does not affect circulating progesterone in gilts1

2019 ◽  
Vol 97 (10) ◽  
pp. 4314-4322 ◽  
Author(s):  
Katie L Bidne ◽  
Matthew R Romoser ◽  
Jason W Ross ◽  
Lance H Baumgard ◽  
Aileen F Keating
Keyword(s):  
Heat Stress ◽  
Heat Dissipation ◽  
Regulatory Protein ◽  
Prostaglandin F2α ◽  
Experimental Treatment ◽  
Corpora Lutea ◽  
Protein Abundance ◽  
Serum Progesterone ◽  
Estrous Cycles ◽  
Seasonal Infertility

Abstract Heat stress (HS) occurs when heat dissipation mechanisms are insufficient to maintain euthermia, and it is associated with seasonal infertility (SI), which manifests as smaller litters, longer wean-to-estrus interval, increased abortions, and reduced conception rates. To understand HS-induced mechanisms underlying SI, crossbred post-pubertal gilts (167 ± 10 kg; n = 14) experienced either thermal neutral (TN, 20 ± 1 °C, n = 7) or cyclical HS (35 ± 1 °C for 12 h and 31.6 °C for 12 h, n = 7) conditions from 2 to 12 d post-estrus (dpe). Estrous cycles were synchronized via altrenogest administration for 14 d, phenotypic manifestation of estrus was observed and gilts were assigned to experimental treatment. Gilts were limit fed 2.7 kg daily with ad libitum water access. Blood was collected at 0, 4, 8, and 12 dpe via jugular venipuncture and animals were humanely euthanized at 12 dpe. The corpora lutea (CL) width were measured via digital calipers on both ovaries, and CL from one ovary were excised, weighed, and protein and steroid abundance analyzed via western blotting and ELISA, respectively. Relative to TN, HS increased (P < 0.01) rectal temperature and respiration rates and reduced (P < 0.01) feed intake. The CL from HS ovaries were reduced in diameter (P < 0.05) and weight (P < 0.01) relative to those from TN animals. No difference (P = 0.38) in CL or serum progesterone concentrations between groups was observed at any time point, though at 12 dpe the serum progesterone:CL weight was increased (P < 0.10) by HS. No treatment differences (P = 0.84) in circulating insulin were observed. Luteal protein abundance of steroid acute regulatory protein, 3 beta-hydroxysteroid, or prostaglandin F2α receptor were not different between treatments (P = 0.73). Taken together, these data demonstrate that the CL mass is HS sensitive, but this phenotype does not appear to be explained by the metrics evaluated herein. Regardless, HS-induced decreased CL size may have important implications to pig SI and warrants additional attention.

scholarly journals Testing the heat dissipation limit theory in a breeding passerine

2018 ◽  
Vol 285 (1878) ◽  
pp. 20180652 ◽  
Author(s):  
Jan-Åke Nilsson ◽  
Andreas Nord
Keyword(s):  
Heat Dissipation ◽  
Work Rate ◽  
Body Temperatures ◽  
Limit Theory ◽  
Ambient Temperatures ◽  
Metabolic Heat ◽  
Thermal Window ◽  
Future Reproduction ◽  
Maximum Work ◽  
Males And Females

The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits ( Poecile palustris ) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.

Variation in maternal attendance patterns and pup behaviour in a declining population of Steller sea lions (Eumetopias jubatus)

1997 ◽  
Vol 75 (8) ◽  
pp. 1241-1246 ◽  
Author(s):  
Wendy R. Hood ◽  
Kathryn A. Ono
Keyword(s):  
Prey Availability ◽  
Population Decline ◽  
High Tide ◽  
Eumetopias Jubatus ◽  
Steller Sea Lions ◽  
Breeding Area ◽  
Foraging Effort ◽  
Sea Lions ◽  
Attendance Patterns ◽  
Breeding Seasons

Maternal attendance patterns of lactating female Steller sea lions (Eumetopias jubatus) and the activity budgets of pups on Año Nuevo Island, California, were compared between the 1973 and 1992 breeding seasons to investigate temporal changes in behaviour that may be associated with population decline. Females were absent from the breeding area longer in 1992, which may reflect increased foraging effort. Pups also spent significantly less time sucking and more time swimming in 1992. Suckling time is correlated with milk intake in some otariid species, thus the decreased amount of time 1992 pups spent sucking could reflect a reduction in the total volume of milk produced by females. Pups in 1992 are likely to have spent more time swimming than pups in 1973 because high tide covered a greater proportion of the study site in 1992 than in 1973. An increase in time females spent at sea and a decrease in time pups spent sucking are consistent with behavioural changes associated with reduced prey availability.

Teaching in Stormy Weather

2019 ◽  
Vol 19 (3) ◽  
pp. 513-517
Author(s):  
Shawna Ross
Keyword(s):  
Climate Change ◽  
Learning Community ◽  
Heat Waves ◽  
Extreme Weather Events ◽  
Weather Patterns ◽  
Weather Events ◽  
Oak Trees ◽  
Event Attribution ◽  
Adverse Weather ◽  
Stormy Weather

This article considers the pedagogical implications of climate change and other environmental catastrophes of the Anthropocene, the new geological epoch identified by climate scientists. In the Anthropocene, the human species has become the most significant force shaping Earth’s geosphere and is responsible for a number of anxiety-producing effects beyond the rise of global temperatures. As erratic weather patterns and extreme weather events have increased, climatologists have been perfecting new methods of single-event attribution capable of linking particular adverse weather events (including droughts, heat waves, flooding tornadoes, and hurricanes) directly to climate change. To provide a concrete example of those universal trends, the author applies her experiences in teaching in Texas, which is strongly marked by long-term forces of anthropogenic environmental devastation (such as the northward migration of the oak trees and alterations in the lithosphere caused by oil extraction). It has also been impacted by hurricanes, floods, and freezes that delayed the onset of the Fall 2017 and Spring 2018 semesters and, in many cases, damaged or destroyed her students’ homes at Texas A&M. The article recounts the strategies that her learning community used to adjust to these exigencies and then offers suggestions for adapting these strategies to other locales.

scholarly journals A stable oxygen isotope record of weather-timescale variability in the Eocene greenhouse world, using the giant marine gastropod Campanile giganteum

2021 ◽  
Author(s):  
Nick Van Horebeek ◽  
Johan Vellekoop ◽  
Alexander J. Clark ◽  
Niels J. de Winter ◽  
Yannick Stroobandt ◽  
...  
Keyword(s):  
High Resolution ◽  
Growth Rates ◽  
Seasonal Pattern ◽  
High Growth ◽  
Extreme Weather Events ◽  
Future Climate Change ◽  
Climate Data ◽  
Marine Gastropod ◽  
Weather Patterns ◽  
Isotope Record

&lt;p&gt;Instrumental climate data are only available for the last few hundred years. To extend this record back in time, climate proxies are used. However, on the geological timescale, the temporal resolution of most paleoclimate records does not provide information about seasonality, let alone events on the weather-timescale. These weather-timescale events are becoming more frequently integrated in models to predict future climate change, but reconstructions of variability with such short timescales in the geological record are extremely rare.&lt;/p&gt;&lt;p&gt;A recent study by de Winter et al. (2020) has revealed that the Eocene giant marine gastropod &lt;em&gt;Campanile giganteum&lt;/em&gt; (Lamarck, 1804) had growth rates exceeding 600 mm/year along the helix, far exceeding those of most other modern and fossil molluscs. With such high growth rates, these giant gastropods have the unique potential to record weather-timescale variability in the Eocene greenhouse world. Therefore, we generated a high-resolution (mm-scale) &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O record on a well-preserved specimen of &lt;em&gt;C. giganteum&lt;/em&gt; from the Paris Basin in Fleury-la-Rivi&amp;#232;re, France, in order to generate a unique ultra-high resolution record of intra-annual, weather-timescale variability in the Eocene. Our preliminary results show a clear seasonal pattern with &amp;#948;&lt;sup&gt;18&lt;/sup&gt;O values ranging between 0.1&amp;#8240; and -2.5&amp;#8240;, superimposed by weekly variations of up to 0.5&amp;#8240;. This could provide insights in weather patterns in the Eocene greenhouse climate and potentially allow the identification of extreme weather events.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;de Winter N.J., Vellekoop J., Clark A.J., Stassen P., Speijer R.P., Claeys P., (2020) The Giant Marine Gastropod &lt;em&gt;Campanile Giganteum&lt;/em&gt; (Lamarck, 1804) as a High&amp;#8208;Resolution Archive of Seasonality in the Eocene Greenhouse World., Geochemistry, Geophysics, Geosystems, 21(4), https://doi.org/10.1029/2019GC008794&lt;/p&gt;

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