An ecological study of the branchiobdellid commensals (Annelida-Branchiobdellidae) of some mid-western Ontario crayfish

Orconectes propinquus and Cambarus robustus from the Speed River, Sunfish Lake, and Laurel Creek, harbor two branchiobdellids, Cambarincola chirocephala and Pterodrilus distichus. Both adult and cocoon populations of the dominant species (C. chirocephala) are proportional to the size of the host throughout the year, except that first-year crayfish are free of cocoons. The reduction in total number of commensals from autumn to spring can be attributed to severe winter conditions. A subrostral site of preference for adult branchiobdellid attachment, and a dominant abdomen I and II site for cocoon deposition are indicated for O. propinquus. On C. robustus, adults are most commonly found on the antennal bases and among the maxillipeds, and cocoons on the last live abdominal sternites. No host specificity is evident although an unidentified Cambarus sp. from Sunfish Lake is free of commensals. Host incompatibility may explain this, but data from Laurel Creek indicate that silting of the microhabitat is responsible for loss of branchiobdellid population. The crayfish–branchiobdellid relationship is commensal, or at most facultatively parasitic, as adult worms can live without a host for extended periods. Serological testing of rabbit serum containing branchiobdellid antibodies against crayfish serum is negative. The dependence of the egg stage on the host for some undetermined factor or factors is discussed. An Asellus sp. fails to pick up the commensals even when exposed under ideal conditions for colonization.

Download Full-text

Renovation of Strawberries Grown on Plastic Mulch to Obtain Multiple Years of Harvest

HortScience ◽

10.21273/hortsci.30.4.800d ◽

1995 ◽

Vol 30 (4) ◽

pp. 800D-800

Author(s):

Peter R. Probasco ◽

Stephen A. Garrison ◽

Joseph A. Fiola

Keyword(s):

Fruit Size ◽

First Year ◽

Severe Winter ◽

Plastic Mulch ◽

Winter Conditions ◽

Ice Accumulation ◽

Winter Temperatures ◽

Winter Severity

Chandler strawberries were planted on plastic mulch in September and renovated at various times after harvest during the next summer. Renovation treatments included mowing, thinning to three crowns/plant, and mowing plus thinning. These treatments were applied to 1-year-old and 2-year-old beds of `Chandler' strawberries. We conducted this study over two harvest seasons to compare winter conditions and the influence of polyester rowcovers. The second harvest season had severe winter temperatures (–5F), along with frequent ice accumulation. Marketable yields, culls, and fruit size were determined from each treatment. Yields varied with the time of treatment and with the degree of winter severity. Fruit size of renovated berries was smaller than first year berries, but still marketable. Polyester covers increased early yields.

Download Full-text

Mass mortality of invasive zebra and quagga mussels by desiccation during severe winter conditions

Aquatic Invasions ◽

10.3391/ai.2014.9.3.02 ◽

2014 ◽

Vol 9 (3) ◽

pp. 243-252 ◽

Cited By ~ 9

Author(s):

Rob Leuven ◽

Frank Collas ◽

K. Remon Koopman ◽

Jon Matthews ◽

Gerard van der Velde

Keyword(s):

Mass Mortality ◽

Severe Winter ◽

Quagga Mussels ◽

Winter Conditions

Download Full-text

Effects of Age, Burial, and Region on Germination and Viability of Halogeton Seed

Weed Science ◽

10.1017/s0043174500030915 ◽

1969 ◽

Vol 17 (1) ◽

pp. 63-65 ◽

Cited By ~ 11

Author(s):

W. C. Robocker ◽

M. C. Williams ◽

R. A. Evans ◽

P. J. Torell

Keyword(s):

Seed Germination ◽

Soil Surface ◽

First Year ◽

Laboratory Conditions ◽

Winter Conditions ◽

Field Germination ◽

Field And Laboratory Conditions ◽

Halogeton Glomeratus

The longevity of brown and black forms of seed of halogeton (Halogeton glomeratus (M. Bieb.) C. A. Mey.), buried at four depths, was determined for a 10-year period in Nevada, Idaho, Utah, and Washington. The black form of seed had almost 100% field germination at all depths by the end of the first year and had completely germinated or was nonviable by the end of the second. Brown seed on the soil surface began field germination the first year at all locations and had germinated or become nonviable at the end of 6 years. Burial at 1, 3, and 6 inches delayed the peak of viability and tended to increase longevity of brown seed. Germination was less than 0.5% at the end of 10 years, and viability was near zero under both field and laboratory conditions. Seed germinated and lost viability most rapidly in Washington, the location where most favorable winter conditions for germination occurred.

Download Full-text

Benthic Fauna Colonization of a New Reservoir with Particular Reference to the Chironomidae

Journal of the Fisheries Research Board of Canada ◽

10.1139/f70-030 ◽

1970 ◽

Vol 27 (2) ◽

pp. 213-232 ◽

Cited By ~ 29

Author(s):

C. G. Paterson ◽

C. H. Fernando

Keyword(s):

Dominant Species ◽

Dominance Hierarchy ◽

Benthic Fauna ◽

Partial Loss ◽

Organic Debris ◽

Wide Range ◽

The Rich ◽

Laurel Creek ◽

Chironomid Fauna ◽

New Reservoir

At the time of first filling of Laurel Creek Reservoir in the spring of 1967 the benthic fauna consisted of submerged terrestrial organisms and obligate and facultative rheophilic species. Two months after initial filling substantial populations of colonizing limnophilic species developed in the habitat whereas the terrestrial and obligate rheophilic components were lost. By the 4th month the fauna was dominated by euryoxybiontic limnophiles and by facultative species. In the period immediately prior to reservoir drainage in the autumn of 1967 the population densities of the euryoxybiontic chironomids declined whereas polyoxybiontic species continued to increase in abundance. These changes in the dominance hierarchy of the chironomid fauna were associated with the partial loss of the rich deposits of organic debris by siltation and decomposition. Survival of winter drainage of the reservoir by many limnophilic species produced an appreciably different pattern of colonization when the reservoir refilled in 1968. During the second summer of the reservoir's existence most euryoxybiontic chironomids further declined in abundance and were replaced by polyoxybiontic forms as the dominant species. The facultative species originally derived from the creek fauna are adapted to a wide range of environmental conditions and the modifications of the reservoir habitat with time had little effect on their abundance.

Download Full-text

Method for Incubating Leaf Tissue to Study Decomposition in Streams

Journal of the Fisheries Research Board of Canada ◽

10.1139/f78-039 ◽

1978 ◽

Vol 35 (2) ◽

pp. 247-248 ◽

Cited By ~ 3

Author(s):

D. C. Eidt ◽

J. H. Meating

Keyword(s):

Leaf Tissue ◽

Severe Winter ◽

Winter Conditions ◽

Leaf Packs ◽

Mesh Bags ◽

Black Plastic

Discs of leaf tissue in mesh bags were incubated inside black plastic tubes secured to the stream bottom. The method minimizes losses of samples due to severe winter conditions and is easier to use than leaf packs or decomposition boxes.

Download Full-text

The crayfish Orconectes virilis: survival in a region with severe winter conditions

Canadian Journal of Zoology ◽

10.1139/z68-032 ◽

1968 ◽

Vol 46 (2) ◽

pp. 207-211 ◽

Cited By ~ 13

Author(s):

D. E. Aiken

Keyword(s):

Physiological Response ◽

River System ◽

Small Degree ◽

Winter Survival ◽

Severe Winter ◽

Orconectes Virilis ◽

Gonadal Maturation ◽

Seasonal Movement ◽

Winter Conditions ◽

Observed Behavior

An attempt was made to determine whether Orconectes virilis from a shallow river system in eastcentral Alberta has evolved a behavioral or physiological response which allows it to survive under the severe winter conditions of this region. From observations and experiments in the field and laboratory it was concluded that O. virilis cannot withstand even a small degree of freezing, and does not actively burrow into mud to escape the danger of freezing. The only observed behavior contributing to winter survival is a seasonal movement of mature animals to deeper water, and this is apparently associated more with gonadal maturation than with winter survival. The results from these experiments indicate that immature animals suffer a higher winter kill than do mature animals, and that winter survival of the species in any region is dependent upon the presence of habitat in which there is some water which does not freeze to the substratum at any time during the year.

Download Full-text

Preparations for Severe Winter Conditions by Emergency Health Personnel in Turkey

Disaster Medicine and Public Health Preparedness ◽

10.1017/dmp.2014.28 ◽

2014 ◽

Vol 8 (2) ◽

pp. 170-173 ◽

Cited By ~ 3

Author(s):

Cüneyt Çalışkan ◽

Aysun Algan ◽

Hüseyin Koçak ◽

Burcu Küçük Biçer ◽

Meltem Şengelen ◽

...

Keyword(s):

Central City ◽

Medical Personnel ◽

Severe Winter ◽

Educational Training ◽

City Center ◽

Ambulance Personnel ◽

Winter Conditions ◽

Emergency Medical ◽

Emergency Medical Personnel ◽

The City

AbstractObjectiveEmergency and core ambulance personnel work under all environmental conditions, including severe weather condtions. We evaluated emergency medical personnel in Çanakkale, Turkey, for their degree of preparedness.MethodsA descriptive study was conducted in Çanakkale, Turkey, within 112 emergency service units and their 17 district stations. Surveys were developed to measure the level of preparedness for serious winter conditions that individual workers made for themselves, their homes, and their cars.ResultsOf the 167 survey participants, the mean age was 29.8 ± 7.9 years; 52.7% were women; more than half (54.75%) were emergency medical technicians; and 53.3% were married. Only 10.4% of those who heated their homes with natural gas had carbon monoxide detectors. Scores relating to household and individual preparation for severe winter conditions increased by participants’ age (P < .003), being married (P < .000) and working in the city center (P < .021); and for men whose cars were equipped with tow ropes, extra clothing, and snow tires (P < .05). Absenteeism was higher for central-city personnel than district workers because they were less prepared for harsh winter conditions (P = .016).ConclusionMany of the surveyed emergency health personel demonstrated insufficient preparations for serious winter conditions. To increase the safety and efficiency of emergency medical personnel, educational training programs should be rountinely conducted. (Disaster Med Public Health Preparedness. 2014;0:1-4)

Download Full-text

Scots roses in Northern Ukraine

Horticultural Science ◽

10.17221/90/2020-hortsci ◽

2021 ◽

Vol 48 (No. 3) ◽

pp. 144-148

Author(s):

Olena Rubtsova ◽

Olena Kolesnichenko ◽

Mykola Shumyk ◽

Oleksandr Shynder ◽

Valentina Chyzhankova ◽

...

Keyword(s):

Frost Resistance ◽

Plant Size ◽

Urban Landscapes ◽

Severe Winter ◽

Winter Conditions ◽

William Iii

The article presents the results of the evaluation of eleven Scots rose cultivars in the northern part of Ukraine due to its severe winter conditions. A range of variations regarding the bloom colour, bloom size, bloom type, flowering incidence, plant size was noticed. The evaluation showed the decorative value and considerable frost resistance of the varieties ‘Double White’, ‘Dunwich Rose’, ‘Frühlingsduft’, ‘Frühlingsgold’, ‘Frühlingsmorgen’, ‘Karl Forster’, ‘Mon Amie Claire’, ‘Red Nelly’, ‘Stanwell Perpetual’, ‘Suzanne’, and ‘William III’. The varieties studied can be used for decorative purposes in urban landscapes in the northern part of Ukraine.

Download Full-text