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Terrestrial and Aquatic Ecology

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Articles 31 - 47 of 47

Full-Text Articles in Life Sciences

Reproductive Health Of The Florida Flock Of Introduced Whooping Cranes, Marilyn G. Spalding, Martin J. Folk, Stephen A. Nesbitt Jan 2008

Reproductive Health Of The Florida Flock Of Introduced Whooping Cranes, Marilyn G. Spalding, Martin J. Folk, Stephen A. Nesbitt

Proceedings of the North American Crane Workshop

We examined the reproductive parameters of the introduced non-migratory flock of whooping cranes in Florida. Of 289 cranes introduced, 67 males and 65 females survived at least 3 years. The first behavioral pairs appeared in 1995, and eggs were first laid in 1999. In total, eggs were laid in 47 nests, 17 chicks hatched, and 4 young fledged by 2005. Severe drought conditions through 2001 were thought to be the reason for low reproductive nest success. In 2003 nesting conditions improved and 71% of nests with eggs, hatched chicks. During the next 2 years, with continued wet conditions, the proportion …


Survival, Movements, Social Structure, And Reproductive Behavior During Development Of A Population Of Reintroduced, Migratory Whooping Cranes, Richard P. Urbanek, Lara E. A. Fondow Jan 2008

Survival, Movements, Social Structure, And Reproductive Behavior During Development Of A Population Of Reintroduced, Migratory Whooping Cranes, Richard P. Urbanek, Lara E. A. Fondow

Proceedings of the North American Crane Workshop

An effort to reintroduce a migratory population of whooping cranes (Grus americana) into eastern North America began in 2001. During 2001-2004, 53 juveniles were released. All chicks were hatched at Patuxent Wildlife Research Center, Maryland, and transferred to Necedah National Wildlife Refuge (NWR), Wisconsin. Chicks were costume/isolation-reared and, with few exceptions, trained to follow ultralight aircraft, which led them to Chassahowitzka NWR, Central Gulf Coast of Florida. All individuals successfully returned to Central Wisconsin during their first spring migration except for the following: 5 individuals that were unable to navigate around Lake Michigan after taking an easterly migration …


Decreased Reproductive Investment Of Female Threespine Stickleback Gasterosteus Aculeatus Infected With The Cestode Schistocephalus Solidus: Parasite Adaptation, Host Adaptation, Or Side Effect?, Eric T. Schultz, Michelle Topper, David C. Heins Jan 2006

Decreased Reproductive Investment Of Female Threespine Stickleback Gasterosteus Aculeatus Infected With The Cestode Schistocephalus Solidus: Parasite Adaptation, Host Adaptation, Or Side Effect?, Eric T. Schultz, Michelle Topper, David C. Heins

EEB Articles

Parasitic infections may cause alterations in host life history, including changes in reproductive investment (absolute amount of energy allocated to reproduction) and reproductive effort (proportion of available energy allocated to reproduction). Such changes in host life history may reflect: 1) a parasite tactic: the parasite adaptively manipulates energy flow within the host so that the host is induced to make a reduction in reproductive effort and reproductive investment, making more energy available to the parasite; 2) no tactic: there is no change in host reproductive effort and reproductive investment simply decreases as a side effect of the parasite depleting host …


The Ecology And Behaviour Of Varanus Mertensi (Reptilia: Varanidae), Phillip J. Mayes Jan 2006

The Ecology And Behaviour Of Varanus Mertensi (Reptilia: Varanidae), Phillip J. Mayes

Theses: Doctorates and Masters

This study examines numerous aspects of the ecology and behaviour of Merten's Water Monitor, Varanus mertensi (Reptilia: Varanidae) including; daily behaviour, diet, foraging behaviour, reproductive seasonality and daily and long-term movements. Findings from over two years of field study of V. mertensi found in waterbodies of both the Ord River Irrigation Scheme and surrounding East Kimberley/Victoria River Downs bioregion of Western Australia are presented. This study simultaneously broadens our understanding of the family Varanidae and provides insight into the life of a semi-aquatic faunal species found in waterbodies of the Ord River Irrigation Scheme.


Natural History And Karyology Of The Yucatán Vesper Mouse, Otonyctomys Hatti, Hugh H. Genoways, Robert M. Timm, Mark D. Engstrom Jan 2005

Natural History And Karyology Of The Yucatán Vesper Mouse, Otonyctomys Hatti, Hugh H. Genoways, Robert M. Timm, Mark D. Engstrom

University of Nebraska State Museum: Mammalogy Papers

Seventeen specimens of the rare Yucatán vesper mouse, Otonyctomys hatti, are now known from Belize, Guatemala, and the Mexican states of Campeche, Quintana Roo, and Yucatán. We herein report a second specimen of O. hatti, from Belize, extending the known geographic range of the species 95 km to the southeast in the country. This is the first location at which O. hatti has been taken sympatrically with the Central American vesper mouse, Nyctomys sumichrasti. We also report data on three additional specimens of O. hatti from Campeche. Nyctomys and Otonyctomys share similar habits and habitat requirements, and …


Reproductive Ecology Of Two Common Woody Species, Juniperus Sabina And Artemisia Santolinifolia, In Mountain Steppes Of Southern Mongolia, Katrin Ronnenberg Jan 2005

Reproductive Ecology Of Two Common Woody Species, Juniperus Sabina And Artemisia Santolinifolia, In Mountain Steppes Of Southern Mongolia, Katrin Ronnenberg

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The present study describes the reproductive ecology of the prostrate shrub Juniperus sabina and the dwarf shrub Artemisia santolinifolia in dry mountain steppes of southern Mongolia. Whereas stands of the juniper are located at the drought limit of the genus’ distributional range, the genus Artemisia is typical of central Asian drylands. Both species produce large numbers of reproductive organs. For Juniperus sabina, however, only 2.5% of the morphologically intact seeds were found to be viable. Correspondingly, neither seedlings nor saplings were found in the field, and recruitment by reseeding happens at most rarely under the present climatic conditions.

Instead, …


Zur Populationsökologie Und Raumnutzung Der Steppenwühlmaus Microtus Brandti (Radde, 1861) In Der Fortpflanzungsperiode, Ulrich Zöphel, N. Dawaa Jan 2005

Zur Populationsökologie Und Raumnutzung Der Steppenwühlmaus Microtus Brandti (Radde, 1861) In Der Fortpflanzungsperiode, Ulrich Zöphel, N. Dawaa

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

During the growing season between 1988 and 1990 the population biology of Brandt’s vole (Microtus brandti) was observed in a population near Ulaanbaatar. Mark-recapture techniques (1,438 markings, 19,606 recaptures in total) and complementary methods were used. The density maximum was observed in July with 98 (1988); 169 (1989) and 94 (1990) individuals/ha and the population fluctuated by a factor of 7.4.

At the beginning of reproductive period the males disperse over a minimum distance of one female home range whereas the females do not migrate after winter. The typical mating system is promiscuity. Youngsters have been recorded from …


First Results Of Wild Ass Research In The South Gobi Aymag/Mongolia In 2003 And 2004, Annegret Stubbe, Michael Stubbe, N. Batsajchan, R. Samjaa, S. Doržderem Jan 2005

First Results Of Wild Ass Research In The South Gobi Aymag/Mongolia In 2003 And 2004, Annegret Stubbe, Michael Stubbe, N. Batsajchan, R. Samjaa, S. Doržderem

Erforschung biologischer Ressourcen der Mongolei / Exploration into the Biological Resources of Mongolia, ISSN 0440-1298

The population of the Mongolian wild ass belongs to the nominate form Equus hemionus hemionus described by Pallas in 1775. This species is adapted to semidesert habitats in the Gobi region and is listed in the Red Book of Mongolia as well as on appendix I of the Washington Convention (CITES). Mapping of the northern border of the distributional range showed a remarkable decrease in size in comparison to the maps of Murzaev (1954) or Bannikov (1954). The pressure of civilization, settlements, motorization, and increasing numbers of domestic livestock in connection with the occupation of water resources and illegal hunting …


Effect Of Food Availability On Reproduction And Brood Size In A Freshwater Brooding Bivalve, Mark Beekey, Ronald H. Karlson Jul 2003

Effect Of Food Availability On Reproduction And Brood Size In A Freshwater Brooding Bivalve, Mark Beekey, Ronald H. Karlson

Biology Faculty Publications

Brood size is often constrained by the amount of energy available to produce offspring. Yet, energetic constraints may not be as important if the physical capacity to brood offspring is limited. Investigating the relative importance of energetic and physical constraints on brood size is necessary to understand how reproductive strategies are molded by natural selection. We investigated how food availability affects brood size in Sphaerium striatinum, a freshwater bivalve. We reared juveniles to adulthood under three food levels in a common garden experiment. The number of reproductive attempts, brood size, and stage of offspring development were measured. Clams reared …


Aspects Of Reproduction And Pair Bonds In Florida Sandhill Cranes, Stephen A. Nesbitt, Martin J. Folk, Stephen T. Schwikert, James A. Schmidt Jan 2001

Aspects Of Reproduction And Pair Bonds In Florida Sandhill Cranes, Stephen A. Nesbitt, Martin J. Folk, Stephen T. Schwikert, James A. Schmidt

Proceedings of the North American Crane Workshop

From 1980-98 we captured and uniquely marked more than 400 Florida sandhill cranes (Grus canadensis prafensis). Age ratios of the marked population, excluding juveniles, was 66% adult and 33% subadult, and the sex ratio was 49% male and 51% female. Average clutch size for 210 nests checked from 1983-97 was 1.78 ± 0.18 (SD) and frequency of l-egg clutches varied among years. Average post-fledging brood size from 1991 to 1997 was 1.27 ± 0.17 (SD), included a 3-chick brood. Average percent ofYOlmg from 2 study areas, 1991-97 was 11.9 ± 3.23 (SD). We observed renesting up to 3 …


Lack Of Reproduction In Muskoxen And Arctic Hares Caused By Early Winter?, L. David Mech Jan 2000

Lack Of Reproduction In Muskoxen And Arctic Hares Caused By Early Winter?, L. David Mech

USGS Northern Prairie Wildlife Research Center

A lack of young muskoxen (Ovibos moschatus) and arctic hares (Lepus arcticus) in the Eureka area of Ellesmere Island, Northwest Territories (now Nunavut), Canada, was observed during summer 1998, in contrast to most other years since 1986. Evidence of malnourished muskoxen was also found. Early winter weather and a consequent 50% reduction of the 1997 summer replenishment period appeared to be the most likely cause, giving rise to a new hypothesis about conditions that might cause adverse demographic effects in arctic herbivores.

Durant l’été 1998, et ce, à la différence de la plupart des années depuis …


Leadership In Wolf, Canis Lupus, Packs, L. David Mech Jan 2000

Leadership In Wolf, Canis Lupus, Packs, L. David Mech

USGS Northern Prairie Wildlife Research Center

I examine leadership in Wolf (Callis lupus) packs based on published observations and data gathered during summers from 1986 to 1998 studying a free-ranging pack of Wolves on Ellesmere Island that were habituated to my presence. The breeding male tended to initiate activities associated with foraging and travel, and the breeding female to initiate, and predominate in, pup care and protection. However, there was considerable overlap and interaction during these activities such that leadership could be considered a joint function. In packs with multiple breeders, quantitative information about leadership is needed.


The Annual Reproductive Cycle Of Oryzomys Palustris In A Virginia Tidal Marsh, Erin A. Dreelin Jul 1997

The Annual Reproductive Cycle Of Oryzomys Palustris In A Virginia Tidal Marsh, Erin A. Dreelin

Biological Sciences Theses & Dissertations

The objectives of my study were to determine when the marsh rice rat (Oryzomys palustris) begins and ends reproduction during the year, if there are seasonal changes in litter size, and the weight at which sexual maturity is reached. Monthly samples of rice rats were trapped from May 1995 to May 1996 in Northampton County, Virginia. Rice rats were trapped with Fitch live traps, euthanized in the field, and brought to the lab for necropsy. Data from two other studies of rice rats in Northampton County were also examined. Potential breeders did not reproduce with equal intensity throughout the …


The Effect Of Disturbance On The Reproduction And Management Of Captive Cranes, Claire M. Mirande, James W. Carpenter, Ann M. Burke Jan 1997

The Effect Of Disturbance On The Reproduction And Management Of Captive Cranes, Claire M. Mirande, James W. Carpenter, Ann M. Burke

Proceedings of the North American Crane Workshop

A retrospective analysis of egg laying histories and observations of crane pairs at the International Crane Foundation and the Patuxent Wildlife Research Center indicates that disturbance associated with captivity has adverse impacts on captive breeding. Females on public display laid significantly fewer eggs than those off display (P < 0.05). Crane pairs moved to other pens (other than adjacent pens) or hetween facilities laid slightly fewer eggs than those birds which were not moved. although the results were not statistically significant (P = 0.188). Pen design and construction also appeared to have adverse impacts on breeding. In addition, human activities, intraspecific interactions, and rearing methods influence a bird's response to disturbance, and, therefore, these factors must also be considered in an effective crane management program. Modifying procedures to minimize disturbance, timing necessary disturbances after the breeding and molt seasons, and carefully monitoring birds for signs of stress can result in increased reproductive potential for captive, endangered cranes.


Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá Jan 1994

Terrapene Carolina Carolina, Joseph C. Mitchell, Rafael O. De Sá

Biology Faculty Publications

TERRAPENE CAROLINA CAROLINA (Eastern Box Turtle). REPRODUCTION. Female Terrapene carolina containing oviductal eggs have been recorded in Virginia from 26 May to 25 July (Mitchell, in press. The Reptiles of Virginia. Smithsonian Inst. Press, Washington, D.C.). Other reports of reproduction in Terrapene (see list in Ernst and McBreen 1991. Cat. Amer. Amphib. Rept. 512.1-512.13) indicate that nesting occurs in late spring and early summer throughout its range.


An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy Apr 1990

An Analysis Of External Features As Predictors Of Reproductive Status In Small Mammals, Kenneth Wayne Mccravy

Biological Sciences Theses & Dissertations

Reproductive status in specimens of nine populations of seven species of small mammals was evaluated by examining the external reproductive features of nipple size, condition of the pubic symphysis, and vaginal condition and, in males, testis position. Usefulness of these external features in predicting true monthly breeding rates was evaluated by comparing predictions of breeding rates with true rates based on necropsy. Accuracy of predictions of reproductive status of individuals based on single external features and combinations of external features and body measurements was then analyzed at a finer level by comparing those predictions with results of necropsy of the …


The Water Vapor Conductance Of Squamate Reptilian Eggs: The Influence Of Scaling On Nesting Ecology., Louis A. Somma Sep 1989

The Water Vapor Conductance Of Squamate Reptilian Eggs: The Influence Of Scaling On Nesting Ecology., Louis A. Somma

Papers in Herpetology

Flexible-shelled eggs of squamate reptiles are strongly influenced by their surrounding microclimate, particularly the hydric conditions of the nest. The eggshell water vapor conductance of an egg can be an indication of its requirement for water from the nest. Ackerman et al. (1985. Physiol. Zool. 58:129-137) have described the scaling relationship for eggshell water vapor conductance (GH2O) of flexible-shelled reptilian eggs (GH2O = 981.8M0.52). This scaling relationship was investigated with water vapor conductance data obtained from 8 species of lizards representing the families Iguanidae (Anolis carolinensis, A. sagrai, Sceloporus woodi, S. virgatus) …