The Annual Cycle of Aggression in Male Microtus Pennsylvanicus, and Its Relation to Population Parameters

Ecology ◽  
1973 ◽  
Vol 54 (5) ◽  
pp. 967-981 ◽  
Author(s):  
Brian N. Turner ◽  
Stuart L. Iverson
Keyword(s):  
Annual Cycle ◽  
Microtus Pennsylvanicus ◽  
Population Parameters

Population parameters of Argentina sphyraena [Isospondyli] from west of Britain

1969 ◽  
Vol 49 (2) ◽  
pp. 407-431 ◽  
Author(s):  
R. G. Halliday
Keyword(s):  
Annual Cycle ◽  
Population Parameters ◽  
Weight Relationship ◽  
Clyde Sea ◽  
Sea Area

IntroductionMonthly samples of Argentina sphyraena L. taken in the Clyde Sea Area over 2 years were used to describe age, growth, length-weight relationship, annual cycle in condition, and mortality. Results indicate that one transparent ring is laid down in the otoliths each year between November and May, providing a means of ageing this species.

Source populations in coastal crabs: population parameters affecting egg production

2009 ◽  
Vol 7 ◽  
pp. 31-43 ◽  
Author(s):  
AAV Flores ◽  
CC Gomes ◽  
WF Villano
Keyword(s):  
Egg Production ◽  
Population Parameters ◽  
Source Populations

Estimating Population Parameters of the Cladocera

1998 ◽  
Vol 34 (4-5) ◽  
pp. 41-49
Author(s):  
V. I. Razlutskii
Keyword(s):  
Population Parameters

Birds in the Dark: Complementary and Partial Information

2017 ◽  
Author(s):  
Graham R. Martin
Keyword(s):  
Annual Cycle ◽  
Colour Vision ◽  
Partial Information ◽  
Night Time ◽  
Light Levels ◽  
Night Feeding ◽  
Nocturnal Species ◽  
Length Changes

Night-time poses exacting problems for vision, resolution inevitably falls and colour vision is not possible as light levels decrease to those of natural night time. Furthermore, light levels are highly variable depending upon whether there is moonlight, and night length changes dramatically in the annual cycle according to latitude. Few birds exploit the resources available at night. Those that do rely upon information received from vision complemented by information from other senses (hearing, olfaction, and touch), and upon highly specialized and restricted behaviours. However, many birds occasionally exploit night-time, e.g. during migration, arriving and departing from nests, and occasional night feeding. Some seabirds dive to such depths that they experience night-time light levels when foraging. Truly nocturnal species such as owls, kiwi, and oilbirds are highly sedentary, and this is essential to allow them to interpret correctly the partial information that is available to them.

scholarly journals Yearly evolution of Euro-Atlantic weather regimes and of their sub-seasonal predictability

2021 ◽  
Author(s):  
Nicola Cortesi ◽  
Verónica Torralba ◽  
Llorenó Lledó ◽  
Andrea Manrique-Suñén ◽  
Nube Gonzalez-Reviriego ◽  
...  
Keyword(s):  
Annual Cycle ◽  
Winter Season ◽  
Skill Score ◽  
Seasonal Forecast ◽  
Forecast Skill ◽  
Seasonal Forecasts ◽  
Sea Level Pressure ◽  
Weather Regimes ◽  
Start Dates ◽  
Weekly Frequency

AbstractIt is often assumed that weather regimes adequately characterize atmospheric circulation variability. However, regime classifications spanning many months and with a low number of regimes may not satisfy this assumption. The first aim of this study is to test such hypothesis for the Euro-Atlantic region. The second one is to extend the assessment of sub-seasonal forecast skill in predicting the frequencies of occurrence of the regimes beyond the winter season. Two regime classifications of four regimes each were obtained from sea level pressure anomalies clustered from October to March and from April to September respectively. Their spatial patterns were compared with those representing the annual cycle. Results highlight that the two regime classifications are able to reproduce most part of the patterns of the annual cycle, except during the transition weeks between the two periods, when patterns of the annual cycle resembling Atlantic Low regime are not also observed in any of the two classifications. Forecast skill of Atlantic Low was found to be similar to that of NAO+, the regime replacing Atlantic Low in the two classifications. Thus, although clustering yearly circulation data in two periods of 6 months each introduces a few deviations from the annual cycle of the regime patterns, it does not negatively affect sub-seasonal forecast skill. Beyond the winter season and the first ten forecast days, sub-seasonal forecasts of ECMWF are still able to achieve weekly frequency correlations of r = 0.5 for some regimes and start dates, including summer ones. ECMWF forecasts beat climatological forecasts in case of long-lasting regime events, and when measured by the fair continuous ranked probability skill score, but not when measured by the Brier skill score. Thus, more efforts have to be done yet in order to achieve minimum skill necessary to develop forecast products based on weather regimes outside winter season.

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