scholarly journals Seasonal activity of the Denali caribou herd, Alaska

Rangifer ◽  
1985 ◽  
Vol 5 (2) ◽  
pp. 32 ◽  
Author(s):  
Rodney D. Boertje
Keyword(s):  
Nutritional Status ◽  
Food Availability ◽  
Nutritional Stress ◽  
Early Spring ◽  
High Availability ◽  
Late Winter ◽  
Seasonal Activity ◽  
Activity Budgets ◽  
West Greenland ◽  
Rest Periods

<p>Activity of female and young caribou in the Denali herd was studied from June 1978 through April 1980 to help assess the food availability/nutritional status of this reduced population. No nutritional stress was evident as inferred by the greater activity of Denali caribou in late winter compared with starving caribou in West Greenland and by the low proportion of time spent grazing in spring compared with reindeer on overgrazed ranges in Norway. Also, low proportions of time were spent running from insects due to relatively few insects and a high availability of insect-relief sites. A low proportion of time was spent cratering due to windswept conditions. Activity budgets calculated from complete active-rest cycles and accompanied by the duration of active and rest periods may be useful indicators of relative food availability/nutritional status, particularly in late winter/early spring. Duration of active periods is presumably most strongly related to rumen fill, and, thus, food availability. Duration of rest periods was not significantly different among seasons (P&lt;0.05), except when insects, rutting bulls, and, presumably, mushroom-searching altered active-rest cycles.</p><p>Sesongmessige svingninger av aktiviteten i Denali karibu-flokk, Alaska.</p><p>Abstract in Norwegian / Sammendrag: Aktiviteten hos simler og ungdyr i Denali karibouflokk ble studert fra juni 1978 til utgangen av april 1980 som hjelpemiddel for &aring; bestemme n&aelig;ringstilbud/ern&aelig;ringsstatus i denne reduserte karibustamme. Ingen ern&aelig;ringsmessig stress var &aring;penbar, noe som kan utledes av den st&oslash;rre aktivitet hos Denali karibu p&aring; senvinteren sammenlignet med sultende karibu i Vest-Gr&oslash;nland samt den lave andel av beiting sammenlignet med rein p&aring; overbelastede beiter i Norge. Videre ble en lav andel av tiden brukt til &aring; r&oslash;mme fra insekter, fordi insektplagen var relativt liten og at det var lett adgang til omr&aring;der der dyrene kunne befri seg fra insektene. Graving krevde ogs&aring; liten andel av tid takket v&aelig;re vindbl&aring;ste sn&oslash;forhold. Aktivitetsbudsjetter beregnet ut fra totale aktivitets-/hvilesykluser kan v&aelig;re nyttige indikatorer p&aring; relativ n&aelig;ringstilbud/ern&aelig;ringsstatus, s&aelig;rlig p&aring; senvinter og tidlig v&aring;r. Varigheten av aktive perioder er sannsynligvis mest knyttet til vomfylde og, derfor, til n&aelig;ringstilbud eller n&aelig;ringstilgjengelighet. Varigheten av hvileperioder var ikke signifikant forskjellig mellom sesonger (P&lt;0.05), unntatt n&aring;r insekter, brunstige bukker og, sannsynligvis ogs&aring;, sopps&oslash;king forandret aktivitet-/hvilesykluser.</p>

Diurnal activity budgets of Black Ducks during their annual cycle in Prince Edward Island

1983 ◽  
Vol 61 (4) ◽  
pp. 743-749 ◽  
Author(s):  
T. Earle Hickey ◽  
Rodger D. Titman
Keyword(s):  
Prince Edward Island ◽  
Behavioral Changes ◽  
Late Winter ◽  
Seasonal Activity ◽  
Continuous Observation ◽  
Activity Budgets ◽  
Yearly Cycle ◽  
Major Activity ◽  
Black Duck ◽  
Tide Level

Scan sampling (N = 68 193 observations) and continuous observation (N = 659 h) of Black Ducks (Anas rubripes) in Prince Edward Island between 19 April 1976 and 1 September 1977 were used to estimate their seasonal activity budgets. Percent of time spent resting increased with increasing wind chill during fall (47.9–63.5%) and winter (76.9–85.5%). Ducks fed less and rested more with increasing tide level during all seasons. Females spent more time feeding than their mates during late winter (9.7%) and the breeding season (15.1%). Behavior of pairs varied depending on the habitat occupied. Feeding was the major activity of Black Duck pairs and of brood hens and ducklings. Resting dominated fall and winter behavior although some sites were more important for foraging during winter. Behavioral changes between seasons apparently reflect different strategies employed by Black Ducks within their yearly cycle.

scholarly journals Seasonal activity and basking of the southernmost population of the freshwater turtle Phrynops hilarii (Chelidae)

2017 ◽  
Vol 38 (2) ◽  
pp. 125-132 ◽  
Author(s):  
María B. Semeñiuk ◽  
Leandro Alcalde
Keyword(s):  
Time Of Day ◽  
Early Spring ◽  
Species Range ◽  
Freshwater Turtle ◽  
Late Winter ◽  
Seasonal Activity ◽  
Key Factors ◽  
Environmental Features

This study focuses on basking behaviour of Phrynops hilarii in the southernmost population of the species’ range. The objective was to determine how environmental features affect the basking behaviour of the species. We analyzed two years of data on the seasonal activity of the species for the same stream. We detected 389 P. hilarii basking, mostly alone (76.8%), and on logs and branches (79.3%), but large turtles used shorelines more frequently than did smaller turtles. Basking peaked during late winter and early spring. We found no correlation between the number of basking turtles and air, substrate or water temperatures. P. hilarii was active through all seasons, with activity peaking in summer, when temperature is highest but basking frequency is low. Type of substrate, time of day, and season are key factors that influence the basking behaviour of P. hilarii.

Coring of laminated lake sediments for pigment and mineral magnetic analyses, Søndre Strømfjord, southern West Greenland

2000 ◽  
pp. 83-89 ◽  
Author(s):  
N. John Anderson ◽  
Amy Clarke ◽  
Rene K. Juhler ◽  
Suzanne McGowan ◽  
Ingemar Renberg
Keyword(s):  
Lake Sediments ◽  
Regional Climate ◽  
Sediment Cores ◽  
Early Spring ◽  
Laminated Sediments ◽  
Late Winter ◽  
West Greenland ◽  
Biological Communities ◽  
Lake Catchment ◽  
Mineral Magnetic

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Anderson, N. J., Clarke, A., Juhler, R. K., McGowan, S., & Renberg, I. (2000). Coring of laminated lake sediments for pigment and mineral magnetic analyses, Søndre Strømfjord, southern West Greenland. Geology of Greenland Survey Bulletin, 186, 83-89. https://doi.org/10.34194/ggub.v186.5220 _______________ Lake sediments are natural archives that provide longterm records of past changes in climate-catchment processes as well as changes in biological communities in lakes. The thousands of lakes in West Greenland are poorly studied but ideally suited to palaeoclimate and lake-catchment interaction projects because of the minimal level of anthropogenic impact and their tight links to regional climate. In 1999, therefore, activity in the Kangerlussuaq / Søndre Strømfjord area (Fig. 1) continued with both a summer limnological sampling programme (Brodersen & Anderson 2000, this volume) and a late winter to early spring expedition to retrieve sediment cores from lakes at the head of the fjord. In our previous coring trips along Søndre Strømfjord we identified a number of lakes with laminated sediments (Anderson & Bennike 1997; Anderson et al. 1999). Initially, it was thought that these finely resolved laminated sediments were restricted to lakes with permanently stratified water columns (meromictic lakes). However, it appears that lakes with laminated sediments are more widespread in West Greenland that hitherto thought.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

TEMPERATURE RESISTANCE OF GOLDFISH MAINTAINED UNDER CONTROLLED PHOTOPERIODS

1959 ◽  
Vol 37 (4) ◽  
pp. 419-428 ◽  
Author(s):  
William S. Hoar ◽  
G. Beth Robertson
Keyword(s):  
Temperature Change ◽  
Seasonal Variations ◽  
Rapid Growth ◽  
Endocrine System ◽  
Early Spring ◽  
Late Winter ◽  
Thyroid Activity ◽  
Temperature Resistance ◽  
Sudden Temperature Change

Goldfish maintained under controlled photoperiods for 6 weeks or longer were relatively more resistant to a sudden elevation in temperature when the daily photoperiods had been long (16 hours) and relatively more resistant to sudden chilling when they had been short (8 hours). The magnitude of the effect varied with the season. Thyroid activity was slightly greater in fish maintained under the shorter photoperiods. The longer photoperiods stimulated more rapid growth of ovaries during late winter and early spring. The endocrine system is considered a link in the chain of events regulating seasonal variations in resistance to sudden temperature change.

Leaf spot and dry rot of lettuce caused by Xanthomonas vitians (Brown) Dowson

1963 ◽  
Vol 14 (6) ◽  
pp. 778 ◽  
Author(s):  
DE Harrison
Keyword(s):  
Leaf Spot ◽  
Early Spring ◽  
Late Winter ◽  
Laboratory Studies ◽  
Dry Rot ◽  
Complete Destruction ◽  
Western Victoria ◽  
Valley Area ◽  
North Western

During the late winter and early spring of 1960, and again to a lesser extent in 1961 and 1962, many lettuce crops in the Murray Valley area of north-western Victoria were seriously affected by a disease characterized by blackening, dry rotting, and collapse of the affected leaves. The incidence of disease varied from about 10% up to practically complete destruction of some plantings. A yellow bacterium was consistently isolated from affected plants and proved to be pathogenic to lettuce. Laboratory studies have shown that the organism agrees closely with the recorded description of Xanthomonas vitians (Brown) Dowson, which has not, apparently, been previously studied in Australia.

Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae)

2014 ◽  
Vol 104 (5) ◽  
pp. 576-585 ◽  
Author(s):  
C. Monzo ◽  
J.A. Qureshi ◽  
P.A. Stansly
Keyword(s):  
Natural Enemy ◽  
Early Spring ◽  
Citrus Greening ◽  
Asian Citrus Psyllid ◽  
Late Winter ◽  
Diaphorina Citri ◽  
Citrus Groves ◽  
Arthropod Fauna ◽  
Predator Exclusion ◽  
Insecticide Sprays

AbstractThe Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of ‘huanglongbing’ (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.

Phenological phases of pollination related to climate change

2021 ◽  
Author(s):  
Samuel Monnier ◽  
Michel Thibaudon ◽  
Jean-Pierre Besancenot ◽  
Charlotte Sindt ◽  
Gilles Oliver
Keyword(s):  
Climate Change ◽  
Pollen Season ◽  
Microscopic Analysis ◽  
Allergic Diseases ◽  
Early Spring ◽  
Late Winter ◽  
General Tendency ◽  
New Production ◽  
Start Date ◽  
Generic Term

&lt;p&gt;Knowledge:&lt;/p&gt;&lt;p&gt;Rising CO2 levels and climate change may be resulting in some shift in the geographical range of certain plant species, as well as in increased rate of photosynthesis. Many plants respond accordingly with increased growth and reproduction and possibly greater pollen yields, that could affect allergic diseases among other things.&lt;/p&gt;&lt;p&gt;The aim of this study is the evolution of aerobiological measurements in France for 25-30 years. This allows to follow the main phenological parameters in connection with the pollination and the ensuing allergy risk.&lt;/p&gt;&lt;p&gt;Material and method:&lt;/p&gt;&lt;p&gt;The RNSA (French Aerobiology Network) has pollen background-traps located in more than 60 towns throughout France. These traps are volumetric Hirst models making it possible to obtain impacted strips for microscopic analysis by trained operators. The main taxa studied here are birch, grasses and ragweed for a long period of more than 25 years over some cities of France.&lt;/p&gt;&lt;p&gt;Results:&lt;/p&gt;&lt;p&gt;Concerning birch but also other catkins or buds&amp;#8217; trees pollinating in late winter or spring, it can be seen an overall advance of the pollen season start date until 2004 and then a progressive delay, the current date being nearly the same as it was 20 years ago, and an increasing trend in the quantities of pollen emitted.&lt;/p&gt;&lt;p&gt;For grasses and ragweed, we only found a few minor changes in the start date but a longer duration of the pollen season.&lt;/p&gt;&lt;p&gt;Discussion:&lt;/p&gt;&lt;p&gt;As regards the trees, the start date of the new production of catkins or buds is never the 1&lt;sup&gt;st&lt;/sup&gt; of January but depends on the species. For example, it is early July for birch. For breaking dormancy, flowering, and pollinating, the trees and other perennial species need a period of accumulation of cold degrees (Chilling) and later an accumulation of warm degrees (Forcing). With climate change these periods may be shorter or longer depending of the autumn and winter temperature. Therefore, a change in the annual temperature may have a direct effect on the vegetal physiology and hence on pollen release. It may also explain why the quantities of pollen produced are increasing.&lt;/p&gt;&lt;p&gt;The Poaceae reserve, from one place to another and without any spatial structuring, very contrasted patterns which make it impossible to identify a general tendency. This is probably due to the great diversity of taxa grouped under the generic term Poaceae, which are clearly not equally sensitive to climate change.&lt;/p&gt;&lt;p&gt;Conclusion:&lt;/p&gt;&lt;p&gt;Trees with allergenic pollen blowing late winter or early spring pollinate since 2004 later and produce amounts of pollen constantly increasing. Grasses and ragweed have longer periods of pollination with either slightly higher or most often lower pollen production.&lt;/p&gt;

Cytokinins and abscisic acid in hardening winter wheat

1990 ◽  
Vol 68 (7) ◽  
pp. 1597-1601 ◽  
Author(s):  
John S. Taylor ◽  
Munjeet K. Bhalla ◽  
J. Mason Robertson ◽  
Lu J. Piening
Keyword(s):  
Triticum Aestivum ◽  
Abscisic Acid ◽  
Winter Wheat ◽  
Leaf Tissue ◽  
Triticum Aestivum L ◽  
Early Spring ◽  
Growth Chamber ◽  
Late Winter ◽  
Sequence Of Events ◽  
Freeze Dried

During overwintering in a northern climate, winter wheat goes through a hardening process, followed by dehardening in late winter – early spring. This sequence of events may be partially controlled by changes in endogenous hormone levels. Crowns and leaf tissue from field grown winter wheat (Triticum aestivum L. cv. Norstar) seeded at the beginning of September were collected and freeze-dried at monthly intervals during the winters of 1985–1986 and 1986–1987. Material was also sampled and freeze-dried from seedlings grown in a growth chamber under hardening conditions (21 °C for 2 weeks plus 3 °C for 6 weeks) or nonhardening conditions (3 weeks at 21 °C). The tissues were analysed for cytokinins and abscisic acid. Cytokinin levels, measured with the soybean hypocotyl section assay, declined from October onwards and then rose to a peak in late winter (January and February, winter 1986–1987; February and March, winter 1985–1986), subsequently declining again. Abscisic acid, quantitated as the methyl ester by gas chromatography with an electron capture detector, increased in level from October to December, then decreased to a relatively low level between January and March. Hardened seedlings from the growth chamber contained significantly higher abscisic acid levels and significantly lower cytokinin levels than did the nonhardened seedlings. Key words: abscisic acid, cytokinins, hardening, Triticum aestivum, winter wheat.

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