Seasonal variation in growth of greater snow goose goslings: the role of food supply

Oecologia ◽  
1998 ◽  
Vol 114 (2) ◽  
pp. 226-235 ◽  
Author(s):  
Denis Lepage ◽  
Gilles Gauthier ◽  
Austin Reed
Keyword(s):  
Seasonal Variation ◽  
Food Supply ◽  
Snow Goose ◽  
Greater Snow Goose

Erratum: Seasonal variation in plant nutritive quality for Greater Snow Goose goslings in mesic tundra

Botany ◽  
2014 ◽  
Vol 92 (2) ◽  
pp. 123-124
Author(s):  
Benoît Audet ◽  
Esther Lévesque ◽  
Gilles Gauthier
Keyword(s):  
Seasonal Variation ◽  
Snow Goose ◽  
Nutritive Quality ◽  
Greater Snow Goose

A Greater Snow Goose from Georgia

The Auk ◽  
1932 ◽  
Vol 49 (2) ◽  
pp. 213-214
Author(s):  
Ivan R. Tomkins
Keyword(s):  
Snow Goose ◽  
Greater Snow Goose

scholarly journals Seasonal variation of mono- and sesquiterpene emission rates of Scots pine

2006 ◽  
Vol 3 (1) ◽  
pp. 93-101 ◽  
Author(s):  
H. Hakola ◽  
V. Tarvainen ◽  
J. Bäck ◽  
H. Ranta ◽  
B. Bonn ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Scots Pine ◽  
Early Summer ◽  
Emission Rates ◽  
High Concentration ◽  
Temperature Dependent ◽  
Emission Pattern ◽  
Defensive Role ◽  
Monoterpene Emission

Abstract. The seasonal variation of mono-and sesquiterpene emission rates of Scots pine was measured from April to October in 2004. The emission rates were measured daily in the afternoons with the exception of weekends. Emissions were measured from two branches; one of them was debudded in May (branch A), while the other was allowed to grow new needles (branch B). The monoterpene emission pattern remained almost constant throughout the measurement period, Δ3-carene being the dominant monoterpene (50-70% of the VOC emission). The standard monoterpene emission potential (30°C) was highest during early summer in June (the average of the two branches 1.35 µg g-1h-1) and lowest during early autumn in September (the average of the two branches 0.20 µg g-1h-1. The monoterpene emission potential of branch A remained low also during October, whereas the emission potential of branch B was very high in October. The sesquiterpenes were mainly emitted during mid summer, the dominant sesquiterpene being β-caryophyllene. Branch A had a higher sesquiterpene emission potential than branch B and the emission maximum occurred concomitant with the high concentration of airborne pathogen spores suggesting a potential defensive role of the sesquiterpene emissions. The sesquiterpene emissions were well correlated with linalool and 1,8-cineol emissions, but not with monoterpenes. Sesquiterpene and 1,8-cineol emissions were equally well described by the temperature dependent and the temperature and light dependent algorithms. This is due to the saturation of the light algorithm as the measurements were always conducted during high light conditions.

scholarly journals Is the quest to eat healthy a route to enhancing consumer’s food security?

2022 ◽  
Vol 11 (1) ◽  
Author(s):  
William A. Kerr ◽  
Jill E. Hobbs
Keyword(s):  
Food Security ◽  
Supply Chains ◽  
Food Supply ◽  
Food Markets ◽  
Individual Level ◽  
Food Supply Chains ◽  
Multiple Dimensions ◽  
Private Standards ◽  
Regulatory Failure

Abstract Background On an individual level, food security has multiple dimensions and consumers exhibit heterogeneity in the extent to which different attributes matter in their quest for enhanced food security. The aim of this paper is to explain how the quest for individual food security arises and its dynamic nature and its implications for how food security-enhancing attributes are defined and how they are signaled, and for the role of regulators and food supply chains in establishing credible signals. Results The paper finds that the quest for enhanced individual food security is a dynamic process that responds to the disequilibrium that change brings. The changing role of standards and grades as signals in food markets is discussed as a precursor to considering the implications for both market and non-market (regulatory) failure in determining the appropriate role for the public sector in regulating food safety and quality standards and labeling. The rise of private standards is examined, along with a consideration of how these standards differ in terms of scope and objective and their implications for international trade in increasingly globalized food supply chains. Conclusions Despite the growth of private standards, a clear role remains for mandatory public standards, yet challenges arise when these standards differ across countries.

scholarly journals The Ecology of Stress: linking life-history traits with physiological control mechanisms in free-living guanacos

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2640 ◽  
Author(s):  
Ramiro J.A. Ovejero Aguilar ◽  
Graciela A. Jahn ◽  
Mauricio Soto-Gamboa ◽  
Andrés J. Novaro ◽  
Pablo Carmanchahi
Keyword(s):  
Life History ◽  
Seasonal Variation ◽  
Reproductive Success ◽  
Hpa Axis ◽  
Life History Traits ◽  
Mating Period ◽  
Entire Study ◽  
Non Invasive ◽  
Animal Populations

BackgroundProviding the context for the evolution of life-history traits, habitat features constrain successful ecological and physiological strategies. In vertebrates, a key response to life’s challenges is the activation of the Stress (HPA) and Gonadal (HPG) axes. Much of the interest in stress ecology is motivated by the desire to understand the physiological mechanisms in which the environment affects fitness. As reported in the literature, several intrinsic and extrinsic factors affect variability in hormone levels. In both social and non-social animals, the frequency and type of interaction with conspecifics, as well as the status in social species, can affect HPA axis activity, resulting in changes in the reproductive success of animals. We predicted that a social environment can affect both guanaco axes by increasing the secretion of testosterone (T) and Glucocorticoid (GCs) in response to individual social interactions and the energetic demands of breeding. Assuming that prolonged elevated levels of GCs over time can be harmful to individuals, it is predicted that the HPA axis suppresses the HPG axis and causes T levels to decrease, as GCs increase.MethodsAll of the data for individuals were collected by non-invasive methods (fecal samples) to address hormonal activities. This is a novel approach in physiological ecology because feces are easily obtained through non-invasive sampling in animal populations.ResultsAs expected, there was a marked adrenal (p-value = .3.4e−12) and gonadal (p-value = 0.002656) response due to seasonal variation inLama guanicoe. No significant differences were found in fecal GCs metabolites between males/females*season for the entire study period (p-value = 0.2839). Despite the seasonal activity variation in the hormonal profiles, our results show a positive correlation (p-value = 1.952e−11, COR = 0.50) between the adrenal and gonadal system. The marked endocrine (r2 = 0.806) and gonad (r2 = 0.7231) response due to seasonal variation in male guanaco individuals highlights the individual’s energetic demands according to life-history strategies. This is a remarkable result because no inhibition was found between the axes as theory suggests. Finally, the dataset was used to build a reactive scope model for guanacos.DiscussionGuanacos cope with the trade-off between sociability and reproductive benefits and costs, by regulating their GCs and T levels on a seasonal basis, suggesting an adaptive role of both axes to different habitat pressures. The results presented here highlight the functional role of stress and gonad axes on a critical phase of a male mammal’s life—the mating period—when all of the resources are at the disposal of the male and must be used to maximize the chances for reproductive success.

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