Geographic Variation in Clutch Size in the Northern Flicker (Colaptes auratus): Support for Ashmole's Hypothesis

The Auk ◽  
1984 ◽  
Vol 101 (4) ◽  
pp. 698-706 ◽  
Author(s):  
Walter D. Koenig
Keyword(s):  
Geographic Variation ◽  
Clutch Size ◽  
Latitudinal Gradient ◽  
Size Variation ◽  
Inverse Correlation ◽  
Climatic Conditions ◽  
Substantial Portion ◽  
Seasonal Fluctuations ◽  
Northern Flicker ◽  
Colaptes Auratus

Abstract The Northern Flicker (Colaptes auratus), a common hole-nesting North American woodpecker, exhibits a highly significant latitudinal increase in clutch size. Using preserved clutches and information on climatic conditions and breeding densities of confamilial species, I examined the hypothesis that this geographic trend is the result of seasonal fluctuations in resources ("Ashmole's hypothesis"; Ashmole 1961, 1963; Ricklefs 1980). Clutch size is significantly correlated both with the ratio of summer productivity to estimated breeding densities of all woodpecker species and with the ratio of summer to winter productivity, supporting Ashmole's hypothesis. In addition, a substantial portion of the latitudinal gradient can be directly explained by the seasonality of resources, primarily because of an inverse correlation between clutch size and winter productivity. These results provide the first corroboration of Ashmole's hypothesis from an examination of intraspecific clutch-size variation and suggest that geographic trends in fecundity in some cases may be largely attributable to trends in seasonal fluctuations of resources.

Geographical differences in seasonal clutch size variation in multi-brooded bird species

Ibis ◽  
2002 ◽  
Vol 144 (4) ◽  
pp. 646-651 ◽  
Author(s):  
André A. Dhondt ◽  
Tracey L. Kast ◽  
Paul E. Allen
Keyword(s):  
Clutch Size ◽  
Bird Species ◽  
Size Variation ◽  
Geographical Differences

Clutch Size Variation and Patterns of Attrition in Fecundity of Willow Ptarmigan

Ecology ◽  
1989 ◽  
Vol 70 (6) ◽  
pp. 1788-1799 ◽  
Author(s):  
K. Martin ◽  
S. J. Hannon ◽  
R. F. Rockwell
Keyword(s):  
Clutch Size ◽  
Size Variation ◽  
Willow Ptarmigan

Extreme rainfall-related clutch size variation in the Critically Endangered Raso Lark Alauda razae of the arid Cape Verde islands

2018 ◽  
Vol 29 (2) ◽  
pp. 321-326 ◽  
Author(s):  
M. de L. BROOKE
Keyword(s):  
Population Size ◽  
Clutch Size ◽  
Size Variation ◽  
Extreme Rainfall ◽  
Cape Verde ◽  
Critically Endangered ◽  
Strongly Correlated ◽  
Cape Verde Islands ◽  
Rainy Period ◽  
Island Endemic

SummaryThe Raso Lark Alauda razae is a single island endemic confined to the island of Raso in the Cape Verde islands. It has been studied via short (11–20 day), similarly-timed visits every year from 2001 to 2017. These November/December visits have occurred towards the end of the main rainy period (August–October) in the Cape Verdes. Average clutch size ranged from zero (no nests found) to 3.57 in different years and was strongly correlated with rainfall in the three months preceding the year’s visit, but not with population size, which varied 25-fold during the study period. Since the nomadic pursuit of rain is not an option for the Raso Lark, the species adjusts clutch size according to conditions prevailing on Raso.

Sedimentological and Geochemical Charectesization of Manaveli and Cuddalore Formations, Puducherry Basin, India

2020 ◽  
Vol 37 (2) ◽  
pp. 115-130
Author(s):  
Shyam Narayan Mude ◽  
Shyam Yawale ◽  
Vishal Choudhari
Keyword(s):  
Grain Size ◽  
Discriminant Function ◽  
Function Analysis ◽  
Size Variation ◽  
Source Area ◽  
Climatic Conditions ◽  
Sieve Analysis ◽  
Element Geochemistry ◽  
Statistical Parameters ◽  
Chemical Index

Sedimentological and Geochemical Charectesization  of Manaveli and Cuddalore Formations, Puducherry Basin, India   Shyam N. Mude, Shyam Yawale and Vishal Choudhari   Department of Geology, Fergusson College (Autonomous), Pune- 411004, India Email: [email protected]; [email protected]   Abstract: The lithostratigraphically rocks of Puducherry basin (Sub-basin of Cauvery Basin) have been classified as Valudavur, Mettuveli, Karasur, Manaveli, Cuddalore formations in ascending order of deposition. The sedimentological and geochemical studies of sediments from Manavali (Paleocene) and Cuddalore (Mio-Pliocene) formations were carried out to understand grain size variation and distribution of major oxides and trace elements.  The sieve analysis was used to study grain size variation and on the basis of grain sizes various geo-statistical parameters were calculated to understand depositional environment. The discriminant function analysis of the sediments from the Cuddalore Formation infers that mostly the sedimentation was occurred in fluvio-deltaic environment with incursions of shallow marine environment whereas bivariate plots suggests that the deposition was occurred in riverine to deltaic environment. The major element geochemistry of the Manaveli and Cuddalore formations have been carried out to understand the provenance, paleoclimate and source area weathering conditions. The values of CIA (Chemical Index of Alteration), CIW (Chemical Index of Weathering), ICV (Index of Compositional Variability) and PIA (Plagioclase Index of Alteration) of the sediments infer high weathering was occurred in source area of sediments for Manaveli and Cuddalore formations.  The ratio (Al2O3+K2O+Na2O)/SiO2 indicate semi-humid climatic conditions during deposition of Cuddalore Formation whereas Manaveli Formation was deposited in semi-arid climatic conditions. The discriminant function diagram (A-CN-K Plot), suggest Quartzose sedimentary provenance for Cuddalore and Mafic igneous provenance for Manaveli Formation.     Keywords:  Grain Size, Geochemistry, Manaveli, Cuddalore, Puducherry Basin

VARIATIONS IN SOIL RADON LEVELS DURING WINTER AND SPRING PERIODS

2020 ◽  
Vol 191 (2) ◽  
pp. 250-254
Author(s):  
Sakhayaan Gavriliev ◽  
Tatiana Petrova ◽  
Petr Miklyaev ◽  
Nikolay Nefedov
Keyword(s):  
Lung Cancer ◽  
Soil Moisture ◽  
Wind Speed ◽  
Activity Concentration ◽  
Inverse Correlation ◽  
Ambient Air ◽  
Climatic Conditions ◽  
Α Decay ◽  
Radon Flux ◽  
Significant Health

Abstract Radon poses significant health risk due to inhalation and subsequent α-decay of its progeny and is the second biggest cause of lung cancer worldwide. In Russian Federation, radon flux density (RFD) measurements are performed routinely to assess radon safety of land lots before construction takes place. This study aims to show possible ‘weather’-influenced variations in RFD and radon activity concentration (RAC) that can occur during winter and spring periods in climatic conditions typical for territories with severe snowy winters. Results show that RFD correlates with weather, having a significant correlation with ambient air temperature in winter as well as spring periods and a weak inverse correlation with wind speed. In spring, RFD also responds to an increase in soil moisture, dropping severely because of rainfall. RAC, however, correlates very little with weather but has a weak inverse correlation with RFD.

Geographic Variation in Body and Clutch Size of Gopher Tortoises

Copeia ◽  
2007 ◽  
Vol 2007 (2) ◽  
pp. 355-363 ◽  
Author(s):  
Kyle G. Ashton ◽  
Russell L. Burke ◽  
James N. Layne
Keyword(s):  
Geographic Variation ◽  
Clutch Size

scholarly journals A growing degree day inference model based on mountain birch leaf cuticle analysis over a latitudinal gradient in Fennoscandia

The Holocene ◽  
2019 ◽  
Vol 30 (2) ◽  
pp. 344-349
Author(s):  
Fabian EZ Ercan ◽  
Hugo Jan De Boer ◽  
Friederike Wagner-Cremer
Keyword(s):  
Latitudinal Gradient ◽  
Growing Season ◽  
Climatic Conditions ◽  
Mountain Birch ◽  
Habitat Conditions ◽  
Inference Model ◽  
Light Regimes ◽  
Latitudinal Transect ◽  
Dwarf Birch ◽  
Epidermis Cell

Cuticle analysis performed on fossil Betula nana (L.) leaves provides a strong proxy to reconstruct past growing season thermal properties expressed as growing degree days (GDD5). This proxy is so far available for the dwarf birch only and, therewith, restricted to regions or past periods of subarctic climatic conditions. In this study, we analysed modern leaf samples of mountain birch ( Betula pubescens spp. czerepanovii (N. I. Orlova) Hämet-Ahti), which has a wider temperature range than the dwarf birch B. nana. The strong latitudinal climate gradient over Fennoscandia provides a unique opportunity to track growing season temperature imprints in the epidermis cell morphology of the modern mountain birch. We quantified the GDD5-dependent epidermal cell expansion, expressed as the undulation index (UI), over a 10° latitudinal transect translating to a range from ~1500°C to ~600°C GDD5 in 2016. Our results indicate that even in mountain birch the UI is positively correlated to GDD5 and, moreover, is largely independent of regional habitat conditions such as daylight length and precipitation. These results imply that in addition to the earlier studied (sub-)arctic dwarf birch, the closely related mountain birch can also be utilized in GDD5 reconstructions. The abundant presence of fossil mountain birch leaves in sediments from warmer than (sub)arctic palaeoclimates enables the reconstruction of growing season climate dynamics over past phases of climate change, overcoming earlier restrictions of the proxy related to spatial and temporal species occurrence as well as local light regimes.

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