bluuebunny/crossref_metadata_2025 huggingface dataset:
Census up‐date: captive marine mammals in North America
Authors: CORNELL LANNY H. , ASPER EDWARD D. , DUFFIELD DEBORAH A.
Published: December 2007

The continued husbandry of marine mammals in captivity has led to increased expertise in methods of care and facility design, and a greater knowledge of breeding requirements. This is clearly reflected in the census up‐date by the increased captive longevities and breeding success, and the decrease in captive mortality. A number of oceanaria channel a major part of their public service effort into recovering stranded animals, maintaining and providing them with medical care. The success of these efforts has been such that for those few species where numbers on display have shown a marked increase from 1976–1979, additions have come mainly from the stranded/rehabilitation programmes or from captive births. Collection pressure on natural populations of marine mammals by the live display industry has been minimal.
COWRI: Critical Ocean Wildlife Recovery Initiative
Authors: BOYLE PAUL , BOLZE DORENE , KOONTZ FRED
Published: December 2007

COWRI, the Critical Ocean Wildlife Recovery Initiative has been developed by the Wildlife Conservation Society, New York, through the Aquarium for Wildlife Conservation and the Osborn Laboratories of Marine Science, with three major objectives: basic and applied research; public awareness and conservation education; marine conservation policy. The authors introduce the concept of COWRI and report on the current progress of the three programme areas.
Reaching out: conservation activities at the National Aquarium in Baltimore
Authors: ANDREWS CHRISTOPHER , KRUSSMAN ROSEMARY , SCHOFIELD DAVID
Published: December 2007

The contribution of public aquariums to conservation has been largely in the field of education but while this may have a direct impact where the aquarium displays local wildlife, it is less immediate where exhibits are international in character. The National Aquarium in Baltimore has developed a number of conservation activities linking the Aquarium's displays to natural habitats. The neotropical rain‐forest exhibit is associated with Costa Rica, and fund‐raising, ‘adoption’ of the national zoo and cooperation with conservation projects are linked with the exhibit. The Aquarium works with the National Marine Fisheries Service programme for the rescue and rehabilitation of stranded marine mammals. It has also launched a coral reef conservation programme to coincide with the reopening of its Atlantic Coral Reef exhibit.
The maintenance of pelagic jellyfish in the Zoo‐Aquarium Berlin
Authors: LANGE JÜRGEN , KAISER RAINER
Published: December 2007

The Zoo‐Aquarium Berlin houses ten species of jellyfish. eight of Scyphozoa and two Hydrozoa. With the exception of the hemisessile Mangrove jellyfish Cassiopea. all are pelagic. This paper examines the differences in the maintenance of each species. The successful husbandry of all these pelagic jellyfish requires not only different types of food for the polyps, growing medusae and adults but also, depending on the species, different types water current and shape of tank.
A case study of inbreeding and juvenile mortality in the population of Nile lechwe Kobus megaceros at Rome Zoo
Authors: FALCHETTI ELISABETTA , MOSTACCI BARBARA
Published: December 2007

The Nile lechwe Kobus megaceros population at Rome Zoo originates from 1.1 wild‐caught animals which arrived in 1959. The ‘harem’ mating system, where the ♀♀ only mate with the dominant J, is typical of this species and because the population has not been genetically managed, the animals have been inbreeding continuously. This study examines the effects of inbreeding depression, particularly in relation to neonate mortality, on this population.
North American Species Survival Plan for Cheetah Acinonyx jubatus
Authors: GRISHAM JACK
Published: December 2007

The North American Species Survival Plan (SSP) for the Cheetah Acinonyx jubatus has developed a cooperative and comprehensive research plan for the long‐term management of the species. Networking with zoos, field biologists and scientists, the SSP has managed the captive population from a situation that was clearly not self‐sustaining into a well‐defined, growing population. This paper describes the development of the SSP and its long‐range goals.
Sand cat Felis margarita: a true desert species
Authors: SAUSMAN KAREN
Published: December 2007

The Sand cat Felis margarita is largely nocturnal and inhabits desert areas in Arabia, Pakistan, the Sahara and Soviet Central Asia. This paper describes the taxonomic classification and status in the wild, and summarizes the history and management of the species in captivity. In the international studbook as at 31 December 1994 there were 79 Sand cats listed in 20 collections: 58 F. m. harrisoni and 21 F. m. scheffeli x F. m. harrisoni hybrids (Sausman, 1995).
Developing a management plan for the African lion Panthera leo ssp in North America
Authors: SHOEMAKER ALAN H. , PFAFF SUE E.
Published: December 2007

The Lion Panthera leo is easily maintained and has bred successfully in captivity. Although the need for management was recognized in 1969, the African lion was considered genetically healthy in captivity and a regional studbook for North America was not approved until 1992. The identification of wild‐born founders has proved to be problematic and for ex situ conservation action to be effective, only animals of known origin are included in the SSP and stud‐book. Of the five extant subspecies that are recognized by the Felid TAG and the SSP, only P. I. krugeri and P. I nubicus have been identified in the North American population, and only P. I. krugeri has any long‐term breeding potential. feline immunodeficiency virus and canine distemper virus have serious implications for management and the SSP has recommended that all felids are tested and FIV‐positive animals isolated. The SSP is seeking to collaborate with workers in Africa who can identify animals that can be exported without adversely affecting in situ conservation status.
The Arabian Leopard Trust, Sharjah
Authors: JONGBLOED MARIJCKE
Published: December 2007

In 1993 a volunteer organization was formed to pro mote the conservation of indigenous wildlife in the United Arab Emirates, particularly the Arabian leopard Panthera pardus nimr. The Arabian Leoparc Trust has been successful in increasing awareness of threatened wildlife and in bringing together single animals, already in captivity, for breeding purposes In 1995 the Trust funded a wildlife and habitat survey which confirmed the existence of a number of species previously unrecorded or believed to be extinct in the area. In October 1995 the Leopard Group of Arabia was established comprising a working committee which aims to promote cooperation between participating countries in captive breeding, research, legislation and the creation of national nature reserves.
Strategies and progress in reproductive research involving small cat species
Authors: SWANSON WILLIAM F. , WILDT DAVID E.
Published: December 2007

Captive populations of small cats are often comprised of fewer than 50 animals that are widely dispersed geographically, making them difficult to study in scientifically meaningful numbers. This paper reviews the progress that has been made in reproductive research and describes how it can be applied to the conservation of small felids. The domestic cat serves as a general reproductive research ‘model’ for felids but normative databases of individual species are still required. Fundamental physiological studies included a 2 year survey of the reproductive status of 186 ♂ felids in Latin American Zoos. Almost 60% of cats produced fewer than 1 000 000 total sperm per ejaculate and several species, including the Margay Leopardus wiedii, Little spotted cat Leopardus tigrinus and Jaguarundi Herpailurus yaguarondi, had low percentages (<40%) of structurally normal spermatozoa. This type of survey can highlight management or husbandry problems which may contribute to poor reproduction. Basic physiological information is essential to developing and applying assisted reproductive techniques, such as ovulation induction, artificial insemination (AI), in vitro fertilization, embryo transfer (ET) and genome resource banking.
Assisted reproduction for managing and conserving threatened felids
Authors: WILDT DAVID E. , ROTH TERRI L.
Published: December 2007

If used appropriately, assisted reproduction, including artificial insemination (AI),in vitrofertilization (IVF), embryo transfer and cryopreservation, has an application for the management and conservation of felids. It is possible that in the future assisted reproduction will enable the movement of genetic material, rather than living animals, between geographically disparate populations. These techniques can also be used to breed sexually incompatible individuals. The cryopreservation of gametes and embryos allows the long‐term storage and protection of existing genetic diversity and provides ‘insurance’ against epidemics and natural disasters. Combined with AI or IVF, cryopreserved gametes and embryos could be used to infuse captive populations with new genetic material without having to take more felids from the wild to support captive‐breeding programmes. Because cats are susceptible to certain infectious viruses, assisted reproduction may be one of the few means of breeding some genetically important individuals using washed and pathogen‐free gametes. Although having many practical advantages, the greatest value of these techniques is for developing a database of the basic reproductive biology that is inherent to each species. Only after this information is known can assisted reproduction be used as a management and conservation tool. In the past 15 years immense progress has been made and there is much information now available on the reproductive physiology of many cat species. For some, such as the CheetahAcinonyx jubatus, this database has allowed offspring to be produced repeatedly using AI. This article provides an overview of some of the species‐specific breeding traits that have been discovered while developing assisted reproduction techniques for felids and how this new knowledge can be applied to improve breeding and management.
Assessing reproductive status in wild felids by noninvasive faecal steroid monitoring
Authors: BROWN JANINE L. , WILDT DAVID E.
Published: December 2007

This paper reviews the current status of faecal hormone metabolite monitoring for assessing the reproductive status of felid species. Monitoring the excreted hormonal metabolites in faeces, which can be collected during routine cleaning of enclosures, permits long‐term assessment of reproductive activity. The non‐invasive nature of faecal hormone monitoring, the ease of collecting biomaterial and the discovery that excretion patterns clearly reflect physiological (gonadal/adrenal) function give this technique enormous potential. After determining the routes of steroid excretion (radio‐label studies), faecal extraction and radioimmunoassay procedures were developed for assessing oestrous cyclicity, seasonality and pregnancy. The primary goal is to obtain clearly defined normative data for all Felidae species, ranging from the onset of puberty through the normal course of prime breeding activity to reproductive senescence. Identifying the type of ovulation (induced versus spontaneous) and the impact of season on reproductive function for each species are high priorities because these two characteristics influence both natural and assisted breeding efforts. The immediate goal is to develop a comprehensive database on the reproductive cycle, seasonality, type of ovulation, duration of the follicular/luteal phase, the feasibility of diagnosing pregnancy/parturition and the influence of stress on reproductive fitness of all extant felid species.
The quarantine station at the National Avian Research Center, Abu Dhabi
Authors: NALDO JESUS L. , SAMOUR JAIME H. , BAILEY TOM A.
Published: December 2007

The National Avian Research Center is a scientific and conservation organization based in Abu Dhabi. The flagship species for the organization are the Houbara bustard Chlamydotis undulata macqueenii and the Saker falcon Falco cherrug. To minimize the risk of infectious diseases being introduced into the Center a quarantine station was built to facilitate the screening of all incoming birds. This paper describes the design of the quarantine station, technical systems, water supply and drainage, and the maintenance and husbandry practices implemented at the station.
Exhibiting mixed‐species groups of sympatric tamarinsSaguinus sppat Belfast Zoo
Authors: HARDIE SCOTT M.
Published: December 2007

In the wild sympatric tamarin species show a high degree of spatial co‐ordination. Stable associations between Saddleback tamarinsSaguinus fuscicollisand members of theSaguinus mystaxgroup (Red‐bellied tamarinSaguinus labiatus, Emperor tamarinSaguinus imperatorand Moustached tamarinS. mystax)have been observed at all sites where the species co‐occur and are related to the stratification of ecological niches within the forest. Since 1992 a study of mixed‐species tamarin groups has been carried out at Belfast Zoo. Stable associations were established between groups ofS. labiatusandS. fuscicollis, and few agonistic interactions were observed. Most aggression involved disputes over food and typically consisted ofS. labiatusdisplacingS. fuscicollis, merely by approaching. Other interactions included some inter‐specific grooming and huddling. This paper describes the introduction procedure and the social and reproductive behaviour of each species within the group, and suggests that mixed‐species exhibits may be a beneficial way of exhibiting tamarins.
Reproduction in a pair of Golden monkeys Pygathrix roxellana at Kobe Oji Zoo
Authors: HAMA NATSUKI , JUN QI HAN , BO DONG , YASUDA SHINJI , MURATA KOICHI , HUA XIAN WAN , GONDO MASAYOSHI
Published: December 2007

In 1992/1993 a study was conducted to measure urinary oestrogen and progesterone in Golden monkeys Pygathrix roxellana. Radio‐immunoassay, enzyme‐immunoassay and the conventional method of measurement were carried out in order to assess which test would identify reproductive status most closely. The procedures used to assay oestrone, oes‐triol and oestradiol are also described. Changes in hormone levels and observed sexual behaviour are discussed and it is concluded that the conventional method of detecting oestrus and pregnancy is an efficient one.
Genetic status of the Brown bear Vrsus arctos in Nordic zoos
Authors: ANDRÉN ROBERT , LAIKRE LINDA , RYMAN NILS
Published: December 2007

The continuing decline of Brown bears Ursus arctos in the wild and the recent discovery of genetic divergence among some wild populations has highlighted the need for a co‐ordinated captive‐breeding programme. This paper discusses some of the effects of extensive inbreeding of Brown bears in Nordic Zoos and examines the degree of genetic variability retained in the present population after a long period of genetically unmanaged breeding. The extent to which the geographic origin of the contributing founders is known is also examined and recommendations are made for future breeding management.
Social behaviour and breeding physiology of a group of Asian elephants Elephas maximus at the Pinnawala Elephant Orphanage, Sri Lanka
Authors: POOLE‘ T. B. , TAYLOR V. J. , FERNANDO S. B. U. , RATNASOORIYA W. D. , RATNAYEKE A. , LINCOLN G. , McNEILLY A. , MANATUNGA A. M. V. R.
Published: December 2007

In 1986 at the Pinnawala Elephant Orphanage, Sri Lanka, a study of 4.4 Asian elephants Elephas maximus was carried out to establish the physical and behavioural changes associated with the ♀ oestrous cycle and the ♂ must cycle. At Pinnawala the elephants are maintained in mixed‐sex groups which has resulted in successful breeding. This paper describes the management of elephants at the orphanage and details their social and reproductive behaviour. It is suggested that successive matings throughout the oestrous cycle and on multiple cycles may be required to ensure successful breeding.
Hand‐rearing Black‐naped hare Lepus nigricollis nigricollis at Coimbatore Zoological Park and Conservation Centre
Authors: ASHRAF N. V. K. , RATHINASABAPATHY B. , GUPTA BRIJ K.
Published: December 2007

Orphaned Black‐naped hare Lepus nigricollis nigricollis leverets were brought to Coimbatore Zoo in July 1994, and January and March 1995. Cow's milk was used to hand‐rear the animals successfully although it has a high lactose and low protein content and is unlike the milk of leporids. Leveret 1 weighed 180 g 3 days after arrival and 750 g 30 days later, a mean increase of 19 g per day. Leveret 2 weighed 250 g on day of arrival and 650 g 30 days later, a mean increase of c. 13 g per day. Leveret 3 gained 235 g in 9 days, a mean increase of 26 g per day. Grass and forbs were offered from day of arrival but were not eaten for c. 10 days.
Zoo and aquarium animal management and conservation: current trends and future challenges
Authors: HUTCHINS M.
Published: December 2007

The turn of the century appears to be a good time to examine the role of zoos and aquariums, both in the past and present, and to predict what role these organizations will play in animal management and conservation in the future. In this review three main trends are considered: (1) the loss of wildlife habitats and, therefore, wildlife, (2) the increase in the number of animal‐welfare and animal‐rights organizations, and (3) the continued urbanization of the Earth's human population. Several predictions and positive action points are given for each trend and if these are taken on board and developed, zoos and aquariums of the future may become leaders in conservation, education and science.
International Species Information System (ISIS): over 25 years of compiling global animal data to facilitate collection and population management
Authors: FLESNESS N. R.
Published: December 2007

In 1973 the International Species Inventory System (ISIS), a computer‐based information system for wild animals maintained in captivity, was established at Minnesota Zoological Garden. By 1989 ISIS (now called the International Species Information System) was an independent organization with a Board of Trustees. Membership of ISIS has increased steadily and at time of writing the pooled database includes information on over 322 000 live tetrapod specimens, over 134 000 fishes (many in groups), plus a larger number of their ancestors, at 595 institutions in 68 countries on six continents. ISIS produces routine pooled inventories and other reports on request and three software tools for personal computers have been developed: arks (Animal Records Keeping System) for maintaining basic specimen records, MedARKS (Medical Animal Records Keeping System) for veterinary records and sparks (Single Population Animal Records Keeping System) for veterinary records, studbooks, genetic and demographic analyses, and Speces Survival Plans. Having collected data for over 25 years, ISIS is also a highly credibile source of information from the zoological community for use by international conventions and regulatory bodies.
Welfare, husbandry and veterinary care of wild animals in captivity: changes in attitudes, progress in knowledge and techniques
Authors: KIRKWOOD J. K.
Published: December 2007

Since the first zoos were founded, attitudes to keeping wild animals in captivity have changed considerably. A much firmer conviction that animals have the capacity for consciousness and thus suffering, has been one factor in the growth in concern for welfare in recent decades. The pursuit of conservation goals and higher welfare standards has driven remarkable advances in the husbandry, veterinary science and care of wild animals.
Birth of Koalas Phascolarctos cinereus at Lone Pine Koala Sanctuary following artificial insernination
Authors: JOHNSTON S. D. , McGOWAN M. R. , O'CALLAGHAN P. , COX R. , HOULDEN B. , HAIG S. , TADDEO G.
Published: December 2007

This paper documents the successful development of an artificial insemination (AI) programme for the Koala Phascolurctos cinereus. The protocols for trials involving two methods to induce ovulation and two insemination techniques are described. In Trial 1, interrupted coitus using a ‘teaser’♂ successfully induced ovulation in nine Koalas. Five ♀♀ were inseminated while conscious using a modified ‘foley catheter’ (Cook insemination catheter) resulting in the births of two offspring. The other four ♀♀ were anaesthetized and inseminated using a technique which allowed visualization of the most cranial portion of the urogenital sinus, where semen was deposited using a 3.5 Fr. ‘Tom‐cat catheter’ (urogen‐itoscopic insemination). Three of the four ♀♀ inseminated by this technique produced pouch young. Microsatellite analysis of DNA from the pouch young excluded the teaser ♀♀ as possible sires, confirming that all offspring were sired by donor sperm. In Trial 2, eight ♀♀ were induced to ovulate by injecting them with 250 International Units of human chorionic gonadotrophin (hCG). A luteal phase was confirmed in all eight ♀♀ but only one gave birth following urogenitoscopic insemination. The Koala pouch young in this study are the first of any marsupial to be conceived and born following A1 procedures. Details of the A1 procedures used are presented and the significance of A1 to the conservation biology of P. cinereus discussed.
Hand‐rearing a Two‐toed sloth
Authors: HARPER L. , EYRE S. , KIBBEY C. , PARTRIDGE J.
Published: December 2007

This article describes the hand‐rearing of a ♀ Two‐toed sloth Choloepus didactylus from birth to its death at the age of 10 months. Developmental issues are discussed in detail, including diet, health, growth and weaning. The infant was successfully introduced to an adult ♀ in preparation for long‐term pairing with a young 3. Socialization, integration and imprinting issues are also discussed. Retrospective analysis concluded that this was a worthwhile hand‐rearing exercise that may he of benefit to others maintaining the species.
Food consumption, growth and food passage times in Pacific Walrus
Authors: KASTELEIN R. A. , KLASEN W. J. C. , POSTMA J. , BOER H. , WIEPKEMA P. R.
Published: December 2007

Between 1978 and 1997 the food consumption and growth of five Pacific Walrus Odobenus rosaries div‐ergens pups were studied at Harderwijk Marine Mammal Park. Four wild‐born pups were hand‐reared on formula and one other pup, born at the Park in June 1995, was suckled by its mother. The two formulas used in this study are described, and the chemical composition and calorific content of one formula and of a sample of Walrus milk are provided. The four hand‐reared pups (and all the hand‐reared Walrus pups reported in the literature) had a lower mass than the suckled pup at similar ages. The suckled pup grew, on average, 18 kg/month during the first 6 months after birth. At the age of 13 months, when two pups were being weaned from formula to a fish diet, the mystacial vibrissae went through a growth spurt. Food passage times were measured by adding carmine red dye to the formula and the median initial passage time was 12 hours in one pup and 17 hours in the other.
REVIEWS
Authors: Thirlby G. F.
Published: December 2007

Essays in Monetary Theory. By D. H. ROBERTSON. (P. S. King & Son, Ltd., 1940.

Survey of British Commonwealth Affairs. Vol. 2: Problems of Economic Policy, 1918–1939, Part 1. By W. K. HANCOCK. (Oxford University Press for the Royal Institute of International Affairs, 1940.

Netherlands India: A Study of Plural Economy. By J. S. Furnivall. Cambridge University Press, 1939.
COMMENT AND REPLY
Authors: WULFSOHN B.
Published: December 2007

A NOTE ON THE REVIEW BY J. C. LAIGHT OF THEORY AND PRACTICE OF COMMEUCE FOR SOUTH AFRICAN STUDENTS BY F. C. TUNSTALL AND B. WULFSOHN IN THE SOUTH AFRICAN JOURNAL. OF ECONOMICS, JUNE 1955. (Val. 23 No. 2, Page 166.)
THE EUROPEAN FREE TRADE ASSOCIATION
Authors: MEIJER S.
Published: December 2007

In The December 1958 issue or this Journal the writer dealt with the main aspects of the European Economic Community1. Since that time there have been a number of significant developments, foremost of which has been the formation, largely at the initiative of the United Kingdom, of a new international grouping known as the “Outer Seven”, embracing the United Kingdom, Sweden, Norway, Denmark. Austria. Switzerland and Portugal.
AN ECONOMIC STUDY OF OPTIMUM FERTILISER APPLICATIONS AND PLANT POPULATION IN MAIZE
Authors: KASSIER W. E. , MALLET J. B.
Published: December 2007

A ‘profit maximisation’ method of statistical analysis, which is fully described, was carried out on a maize fertiliser and plant population trial conducted at Cedara.

Under the cost structure assumed it was found that the optimum profit level was to be obtained from an application of 143.9 lb. of N as limestone ammonium nitrate, 154.2 lb. of K2O as potassium chloride and a plant population of 34,881 plants per morgen. As no increase in yield was obtained from further applications of phosphate above the lowest level of 95 lb. P2O6 per morgen, this nutrient was excluded from the analysis.

Should grain prices rise or fall, the increase or decrease in the rates of fertiliser application can be calculated, so as still to obtain the most economic return.
BOOK REVIEWS
Authors: Plessis T. A. du
Published: December 2007

Book reviewed in this article:

Quantitative Economic Theory, A Synthetic Approach, by Hans Brems.
THE MARKETING OF SOUTH AFRICAN MAIZE*
Authors: BRITS R. N.
Published: December 2007

Any study of the various techniques used to market South African maize both domestically and abroad requires some preliminary information concerning the actual production of maize in South Africa.
Speed of Sound in Metal Pipes: An Inexpensive Lab
Authors: Huggins Elisha
Published: December 2007

Our favorite demonstration for sound waves is to set up a compressional pulse on a horizontally stretched Slinky™. One can easily watch the pulse move back and forth at a speed of the order of one meter per second. Watching this demonstration, it occurred to us that the same thing might happen in a steel pipe if you hit the end of the pipe with a hammer. The main difference is that the speed of sound in steel is close to 5000 meters per second. If you hit the end of a 10-ft (3.05-m) pipe, the pulse should take about 1.2 ms to go down and back, a time conveniently measured by an oscilloscope.
Physics of Incandescent Lamp Burnout
Authors: Gluck Paul , King John
Published: December 2007

Incandescent lamps with tungsten filaments have been in use for about a century while being gradually replaced by fluorescent lamps; in another generation both will quite probably be largely replaced by light-emitting diodes. Incandescent lamps (simply called lamps in what follows) burn out after a lifetime that depends mostly on the temperature of the filament and hence the applied voltage. A full-term project (about 100 hours) on lamp burnout was carried out by two students in 1965 and has been briefly described.1 Many aspects of the physics of lamps have been dealt with in articles that have appeared in this journal, in the American Journal of Physics, and in Physics Education.2,3
A Free-Form Power Experiment to Enhance Student Creativity
Authors: Fons John T.
Published: December 2007

Laboratory sessions offer students an opportunity to develop creative problem-solving skills and to better understand the nature of the scientific process through hands-on learning. Unfortunately, traditional procedures are often written in such detail, they require students to do little more than follow step-by-step directions. Under those circumstances, students do not have the opportunity for creative and critical thinking and often lose appreciation for the laboratory setting.1 To encourage student creativity in the lab, I assign a free-form exercise that requires students to measure their power output when performing an activity of their choosing. Students develop their own experimental procedure and analysis restricted only by equipment availability and safety. The short handout I provide for my students contains no formal procedure or guidelines; it simply lists the requirements for their reports.
A field study of competition and interaction between Lemna minor and Lemna trisulca
Authors: McIlraith Alexander L. , Robinson Gordon G. C. , Shay Jennifer M.
Published: December 2007

Field experiments and survey methods were used to assess competition and interaction between Lemna minor L. and Lemna trisulca L. at Delta Marsh, Manitoba. Sites were dominated by one or the other species or codominated by both. Replacement series experiments predicted codominance of L. minor and L. trisulca in an unshaded eutrophic site but predicted L. minor dominance when run for a longer time. Similar experiments conducted in a shaded eutrophic site predicted L. minor dominance. Addition series experiments showed that intraspecific and interspecific competition occurred in the unshaded site. In a eutrophic unshaded ditch, high densities of L. minor suppressed L. trisulca. In a eutrophic shaded site, high densities of L. minor and green algae inhibited L. trisulca, and in a sunny, less eutrophic site high density of each species inhibited the other. In a transplant experiment, L. minor biomass in shaded enclosures approached that found naturally in two shaded sites. Lemna trisulca persisted when shaded. Vegetative biomass trends in an unshaded eutrophic marsh ditch indicated spring and fall L. trisulca dominance and summer L. minor dominance. Shaded eutrophic sites were dominated by L. minor, whereas a less eutrophic site was dominated by L. trisulca. A model is developed to explain dominance patterns, and seasonal life-history responses are considered. Key words: Lemna, duckweed, competition, interaction, resources, light, nutrients.
The morphology and relationships of Equisetum fluviatoides sp.nov. from the Paleocene Ravenscrag Formation of Saskatchewan, Canada
Authors: McIver E. E. , Basinger J. F.
Published: December 2007

Vegetative and associated fertile remains of Equisetum have been recovered from early Tertiary sediments of the Ravenscrag Formation, Saskatchewan, Canada. The morphology of both reproductive and vegetative organs of this fossil species is remarkably similar to that of extant Equisetum fluviatile, the swamp horsetail. Aerial axes of the fossil are 3.0–19.0 mm in diameter, with internodal lengths of up to 30.0 mm. The stems are hollow and the central cavity is large. Branches, apparently simple, are borne in whorls at the nodes. Leaf collars at the nodes are up to 23.0 mm long, longer than broad, with leaves fused in the lower four-fifths of the collar. The leaf apices are long attenuate. Cones are up to 14.0 mm long, bearing peltate, six-sided sporangiophores in whorls of five. The fossil record suggests stasigenesis in the evolutionary history of some members of the genus Equisetum since the beginning of the Tertiary, and perhaps longer.
Acid extension in vitro of epidermal tissues from Phaseolus vulgaris hypocotyls
Authors: Keller Christopher P. , Taylor Iain E. P.
Published: December 2007

Frozen–thawed epidermal strips prepared from the first centimetre below the hypocotyl hook of 6-day-old dark-grown Phaseolus vulgaris seedlings were loosened by transfer from a bathing solution of pH 7.5 to solutions ranging from pH 6.0 to pH 2.6 (0.05 M citric acid – 0.10 M disodium phosphate). A minimum stress of between 1.6 and 7.6 g was required for the acid extension of strips that were 4.5 ± 0.5 mm wide. Tissues in acid media initially extended rapidly, but this was followed by only limited long-term extension. Substantial sustained extension rates were only achieved using extreme tension, which was judged to exceed that naturally occurring in these cell walls, or following abrasion of the epidermal surface. Although acidic β-glucosidase, β-galactosidase, β-xylosidase, and α-galactosidase activities were eliminated by boiling for 15 min in ethanol or extraction in 6 M LiCl for 8 h at 4 °C and lowered by 70–80% by extraction in 3 M NaCl for 4 h, total acid extension of strips over 1 h was less affected by these treatments. Although this result suggests that glycosidases and any other similarly soluble enzyme are not responsible for acid wall loosening, it is not considered conclusive.
Studies on the Stellaria longipes polyploid complex (Caryophyllaceae): characterization of the genetic basis of isozymes
Authors: Cai Q. , Chinnappa C. C.
Published: December 2007

The isozymes for 10 enzyme systems were electrophoretically investigated in Stellaria longipes and Stellaria longifolia. Twenty-six isozymes were detected in S. longipes, 21 of which were found in S. longifolia. Twenty-six gene loci were inferred to control these isozymes; 19 were confirmed by selfing and crossing experiments. The intergenic relationships were examined among 34 pairs of genes. The genetic basis of isozymes was documented. Only four pairs of genes are inherited as linkage, and others were confirmed to be inherited independently.
Vegetation patterns in James Bay coastal marshes. III. Salinity and elevation as factors influencing plant zonations
Authors: Earle J. C. , Kershaw K. A.
Published: December 2007

Plant zonations and selected environmental variables were studied in a subarctic coastal marsh at Ekwan Point, James Bay, Ont. Eight distinct community types were identified using two-way indicator species analysis classification (TWINSPAN). These were interpreted as a primary successional sequence. The eight communities were found to conform closely to the classical marsh zonations based on elevation and tidal influence: (1) lower salt marsh, (2) middle salt marsh, (3) upper salt marsh, (4) saline meadow, (5) freshwater meadow, and (6) freshwater fen. Environmental data collected along the vegetation transects indicated that changes in elevation and soil-water salinity probably influence species distributions. A species ordination using detrended correspondence analysis (DECORANA) revealed several trends in plant distribution patterns. Consideration of the environmental affinities of species separated along three ordination axes suggested that salinity and elevation, water content, and soil texture were probably important factors influencing successional processes in the marsh during at least the last century. An inverse salinity gradient, which has been reported at many sites along the west coast of Hudson and James bays, was not found at Ekwan Point.
The structure and development of the haustorium in Cuscuta australis
Authors: Lee Kyu Bae , Lee Chai Doo
Published: December 2007

The structure and development of the haustorium of a parasitic angiosperm Cuscuta australis R. Brown growing on the host plant Trifolium repens L. was studied with light and electron microscopy. The upper haustorium, which lies external to the host organ, initiates endogenously from cortical cells of the middle layers of the parasite stem. The initial cells develop into a group of meristematic cells. As haustorial maturation progresses, the meristematic cells develop into an endophyte primordium that penetrates the host tissue. The endophyte primordium consists of three cell types: (i) remarkably enlarged elongate cells (digitate cells) with very dense cytoplasm and large nuclei at the central region; (ii) smaller file cells with prominent nuclei proximal to the digitate cells; and (iii) highly compressed cells distal to the digitate cells. Evidence suggests that the digitate cells are metabolically very active. The endophyte, which lies internal to the host tissue, consists of parenchymatous axial cells and elongate tip cells with dense cytoplasm and conspicuous nuclei. The axial and tip cells of endophyte are interpreted as originating from the file and digitate cells of the endophyte primordium, respectively. The tip cells independently penetrate the host tissues and transform into the filamentous hyphae. The hyphae reach the host vascular tissues and eventually differentiate into xylary or phloic conductive hyphae.
A biogeographical overview of the Canadian mushroom flora
Authors: Redhead S. A.
Published: December 2007

Maps showing the North American distributions of 74 species of fleshy fungi, mainly Agaricales, are used to demonstrate variations in fungal ranges. Each map is based on examined specimens or selected literature. The maps are arranged to show North American floristic patterns, while the species in the text are grouped along worldwide patterns. Range patterns resemble those reported for vascular plants, ascolichens, and bryophytes. The names Hypholoma flavifolium (Smith) comb.nov. and Strobilurus trullisatus var. montezumae (Singer) comb. & stat.nov. are proposed.
Different nitrogen sources for fertilizing western hemlock in western Washington
Authors: Radwan M. A. , DeBell D. S. , Webster S. R. , Gessel S. P.
Published: December 2007

Effects of different sources of fertilizer N on selected chemical characteristics of soils and foliage, and on growth of western hemlock (Tsugaheterophylla (Raf.) Sarg.) were compared at three different sites in western Washington. Treatments were the following: untreated control (O), ammonium nitrate (AN), ammonium sulfate (AS), calcium nitrate (CN), urea (U), and urea – ammonium sulfate (US). Fertilizers were applied in the spring (April–May) at 224 kg N/ha. Forest floor and mineral soil, to a depth of 5 cm, and foliage were sampled periodically for 2 years. Height and diameter of selected trees were measured periodically for 4 years. Results are reported mostly for two sites, one in the Cascade Range and one in the coastal zone in western Washington. The pH of forest floor and mineral soil varied by treatment, and the two urea fertilizers caused substantial initial rise. Effects on soil and foliar nutrients varied by fertilizer, sampling date, and location. In general, all fertilizers increased NH4 N, N03 N, and total N in the forest floor and mineral soil, and total N in the foliage. Also, with some exceptions, especially with foliar P in the Cascade site, fertilization reduced foliar content of important nutrients. At the Cascade site, 4-year growth responses in height, basal area, and volume averaged over all fertilizers were 30, 34, and 32%, respectively. AN, AS, CN, and urea resulted in height growth significantly (P < 0.20) higher than that of the control. Significant basal area growth and volume-growth responses were produced by AN, CN, and US. No significant height-growth response to any fertilizer occurred in the coastal stand; basal area growth and volume-growth responses averaged 27 and 21%, respectively, and best response occurred with urea. These results suggest that the low and inconsistent response of hemlock to N fertilization cannot be improved by applying some N fertilizer other than urea. Factors limiting response to N fertilization may be associated with availability of native N and other nutrients or other characteristics of hemlock sites and stands.
A canopy model (RM-CWU) for determining transpiration of subalpine forests. II. Consumptive water use in two watersheds
Authors: Kaufmann Merrill R.
Published: December 2007

A canopy transpiration model, RM-CWU, was used for estimating consumptive water use (CWU) of subalpine forest stands in the Rocky Mountains. Annual CWU was calculated for nine subunits in two watersheds on the Fraser Experimental Forest near Fraser, CO. Calculated CWU of the forested portions of the subunits ranged from 305 to 460 mm • year−1. After combining these rates on an area-weighted basis with evapotranspiration estimates of the nonforested areas of each subunit, annual subunit CWU rates varied from 159 to 388 mm • year−1. Annual CWU for the Lexen Creek watershed was 352 mm • year−1; for the East St. Louis Creek watershed CWU was 264 mm • year−1. Annual CWU calculated for each watershed with RM-CWU was compared with completely independent estimates of evapotranspiration (ET) determined as the difference between precipitation input and watershed runoff. Using two different estimates of precipitation input, two ET estimates were obtained for each watershed. For both watersheds, CWU calculated with RM-CWU was within several percent of the ET estimates expected to be the most accurate. This suggests that CWU estimates from a physiologically based canopy transpiration model may be used to determine water vapor loss from watersheds in the Rocky Mountains.
Biomass and leaf area in contrasting lodgepole pine forests
Authors: Pearson John A. , Fahey Timothy J. , Knight Dennis H.
Published: December 2007

Bole, branch, foliage, root crown, and lateral root biomass of Pinuscontorta ssp. latifolia (Engelm. ex Wats.) Critchfield forests in southeastern Wyoming were estimated by a combination of aboveground dimension analysis, belowground planar intersect sampling, and soil coring. Total biomass of six stands ≥75 years old ranged from 123 to 180 Mg/ha, and roof:shoot ratios were much higher in two very dense stands than in four more open stands. Average proportions of biomass in boles, branches, foliage, woody roots, and fine roots were 61, 7, 6, 20, and 6%, respectively. Leaf area index ranged from 4.5 to 9.9. Leaf area per unit sapwood area ranged from 0.20 to 0.57 m2/cm2in stands of different densities, ages, and sites. Sapwood area was a more precise predictor of foliage biomass than was basal area for the low to moderate density stands, but was marginally inferior to basal area for two high density stands (>9000 trees/ha).
Nitrogen transformations in feather moss and forest floor layers of interior Alaska black spruce ecosystems
Authors: Weber M. G. , Cleve K. Van
Published: December 2007

Permafrost-free and permafrost-dominated black spruce (Piceamariana (Mill.) B.S.P.) ecosystems in interior Alaska were treated with low addition levels of high enrichment isotope (<1% of the total nitrogen pool with 99 at.% excess 15N) to describe nitrogen dynamics through pools of selected forest floor components. A thick carpet of mosses, made up primarily of the feather moss species Hylocomiumsplendens (Hedw.) B.S.G. and Pleuroziumschreberi (B.S.G.) Mitt, seemed to play a vital role in the nitrogen economy of the forest floor. Nitrogen, quickly immobilized in the moss layers (green, brown) and retained there, was released very slowly to the lower organic layers (021 + 022) where most of the vascular plant roots were located. 15N uptake by the vascular understory was minimal, as was15Nexport via the soil solution. Periodic mineralization episodes, more frequent and dynamic at the permafrost-free site (where C/N ratios were lower), were largely restricted to the moss layers since available N fractions in deeper forest floor layers incorporated little label over the 3-year period. In the lower layers of the forest floor (021 + 022) temperature rather than organic matter quality appeared to be the overriding factor controlling N flow.
The effects of photoperiod and temperature on gibberellin A4/7 induced strobilus production of western hemlock
Authors: Pollard D. F. W. , Portlock F. T.
Published: December 2007

Combinations of photoperiod and temperature were tested in two experiments to determine their effect during and after gibberellin A4/7 promotion of flowering in seedlings or cuttings of western hemlock (Tsugaheterophylla (Raf.) Sarg.) In the first experiment, longer photoperiods (18 h) applied during induction favoured male strobili, while hosrter photoperiods (13 h) favoured females. More strobili of both sexes were produced at 30 °C than at 20 °C. In the second experiment, treatments applied in October and November following spring induction also affected subsequent numbers of strobili produced. Darkness at 11.1 °C severely reduced strobilus production, whereas increasing photoperiods, up to the 8-h maximum tested, and lower temperature (5.6 °C), favoured expression of reproductive potential. Results indicate that temperature and photoperiod manipulations can be critical to the production of strobili in controlled environment seed orchards. Furthermore, they suggest that environmental conditions between induction and spring flush may be as important as conditions during induction for the realization of reproductive potential of western hemlock.
Effects of natural chilling and cold storage on budbreak and root growth potential of loblolly pine (Pinustaeda L.)
Authors: Carlson W. C.
Published: December 2007

One-year-old loblolly pine (Pinustaeda L.) seedlings of 20 open-pollinated families were lifted from the nursery on November 23, 1981, and January 18, 1982, after the accumulation of 207 and 734 chilling hours (0 °C ≤ temperature ≤ 8 °C), respectively. Seedlings were tested for bud dormancy (rest) intensity and root growth potential after lifting and after 500 h in cold storage. There was a twofold range in dormancy intensity of 20 families at 207 chilling hours. Bud dormancy intensity was reduced as rapidly in cold storage as in nature. At 1234 chilling hours (500 h of which were in storage), families did not significantly differ in dormancy intensity. Root growth potential was severely reduced by storage (500 h at 2–4 °C) of seedlings lifted on November 23. In contrast, root growth potential of similarly stored seedlings lifted January 18 either was unaltered or had improved in storage.
Relation between root system size and water inflow capacity of Abiesamabilis growing in a subalpine forest
Authors: Teskey Robert O. , Grier Charles C. , Hinckley Thomas M.
Published: December 2007

The water inflow capacity of the root systems of several 15- to 18-year-old Pacific silver fir (Abiesamabilis (Dougl.) Forbes) trees was investigated under field conditions. Severance of as much as one-third of the roots had no effect on xylem pressure potential, leaf conductance, or transpiration throughout the day following this treatment. Severance of more than half of the root system caused a decline in xylem pressure potential and partial stomatal closure. Measurements from trees which had been completely severed from their roots indicated that stored water made only a small contribution to the supply of water to the foliage of these trees. It was concluded that a balance did not exist between the capacity for water inflow and the rate of foliar water loss, at least in periods without drought. One advantage of excess absorptive capacity may be the ability to obtain adequate amounts of water from relatively small portions of the rooting zone.
Effects of phosphorus and vesicular–arbuscular mycorrhizae on growth and leaf retention of black walnut seedlings
Authors: Kormanik Paul P.
Published: December 2007

Black walnut seedlings were grown in fumigated soil without vesicular–arbuscular (VA) mycorrhizal fungi or in soil infested with Gigasporamargarita, Glomusfasciculatum, or Glomusmacrocarpum. For each mycorrhizal treatment, three levels of available phosphorus (P), 25, 50, and 75 ppm, were provided. With 25 and 50 ppm P, the presence of VA mycorrhizae significantly improved leaf retention and root weight of all seedlings. At 75 ppm P, seedling development was not affected by mycorrhizal treatment. Within a given mycorrhizal condition, there were only minor differences in growth parameters across P levels. In the nonmycorrhizal treatments, all growth parameters significantly improved at the 75 ppm P treatment, while little difference could be detected between 25 and 50 ppm P. The number of lateral roots with a diameter of 1.0 mm or larger and root weight of seedlings were not affected by soil P level within a mycorrhizal treaement, but each increment of soil P increased root weight but not the number of lateral roots of seedlings in the nonmycorrhizal treatment. Seedlings that were mycorrhizal with G. margarita had more dense root colonization and were characteristically larger than seedlings that were mycorrhizal with either G. fasciculatum or G. macrocarpum across all P levels.