80 results
Search Results
2. A career of bat research: informing and motivating bat conservation.
- Author
-
Brigham, R. Mark and Wee, Naomi M.J.
- Subjects
BAT conservation ,ENDANGERED species ,BATS ,WORKS councils ,DEMOGRAPHIC change - Abstract
Bat conservation has become prevalent over the last few decades due to critical population declines worldwide. Our purpose was to assess whether Brock Fenton's research career coincided with increasing bat conservation research in Canada and North America. Fenton has made significant contributions to bat research during a long and productive publishing career accompanied by participation in research organizations like the North American Society for Bat Research and the Natural Sciences and Engineering Research Council. His conservation research as well as efforts to raise public awareness about these animals has coincided with work for the Committee on the Status of Endangered Wildlife in Canada and its equivalent (Committee on the Status of Species at Risk in Ontario) in ON. To assess the impact of his career, we quantified the relative amount of his peer-reviewed publications with a conservation focus and compared this with the level of conservation-related presentations at annual North American Society for Bat Research conferences. In the same manner, we assessed how often conservation-focused applications were funded by the Ecology and Evolution section of the Natural Sciences and Engineering Research Council—Canada Discovery grant program. Although it cannot be said with authority that Fenton actually initiated the increase in bat conservation research, our results indicate that his research efforts coincide with and presumably had considerable influence in driving this area of research. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
3. The physiological state of four commercially important bivalve species during a naturally occurring heatwave.
- Author
-
Talevi, Jasmine, Steeves, Laura, Coffin, Michael, Guyondet, Thomas, Sakamaki, Takashi, Comeau, Luc, and Filgueira, Ramón
- Subjects
MYA arenaria ,HEAT waves (Meteorology) ,BIVALVES ,NORTHERN quahog ,MARINE heatwaves ,AMERICAN oyster - Abstract
Shallow coastal environments are becoming more susceptible to marine heatwaves, particularly in Atlantic Canada, which is experiencing higher rates of ocean warming compared with the global average. Understanding bivalves' tolerance to heatwaves in Atlantic Canada is especially important, given the magnitude of bivalve aquaculture in this region. In this study, the physiological state of four commercially important bivalve species—blue mussel (Mytilus edulis Linnaeus, 1758), eastern oyster (Crassostrea virginica (Gmelin, 1791)), soft shell clam (Mya arenaria Linnaeus, 1758), and hard clam (Mercenaria mercenaria (Linnaeus, 1758))—was observed during a naturally occurring heatwave in Prince Edward Island, Canada. The metabolism, feeding physiology, and scope for growth of each species were compared. Results from this study, and comparisons with the literature, show interspecific variability in the metabolic rate and feeding physiology between species, but generally oysters, soft shell clams, and hard clams were less impacted during the heatwave compared with the blue mussels. Additionally, only the scope for growth of mussels declined throughout this experiment, which may be explained by cumulative heat stress, as temperatures experienced during this heatwave exceeded the thermal tolerance limits of mussels. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
4. The status of taxonomy in Canada and the impact of DNA barcoding.
- Author
-
Packer, L., Grixti, J. C., Roughley, R. E., and Hanner, R.
- Subjects
TAXONOMISTS ,ENTOMOLOGISTS ,RESEARCH institutes ,RESEARCH grants ,RESEARCH funding ,ENDOWMENT of research ,SURVEYS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2009
- Full Text
- View/download PDF
5. Quantifying barrier effects of roads and seismic lines on movements of female woodland caribou in northeastern Alberta.
- Author
-
O'Neill, Jack P. and Boutin, Stan
- Subjects
WOODLAND caribou ,ROADS & the environment ,HABITATS ,ANIMAL mechanics ,WILDLIFE conservation ,TAIGAS - Abstract
Linear developments such as roads, seismic lines, and pipeline rights-of-way are common anthropogenic features in the boreal forest of Alberta. These features may act as barriers to the movement of threatened woodland caribou, Rangifer tarandus caribou. Seismic lines were not barriers to caribou movements, whereas roads with moderate vehicle traffic acted as semipermeable barriers to caribou movements. Twenty-two adult female and 1 adult male woodland caribou were captured and collared on February 17–19, 1998. Each caribou was fitted with a global positioning system collar. The greatest barrier effects were evident during late winter, when caribou crossed actual roads 6 times less frequently than simulated road networks. Semipermeable barrier effects may exacerbate functional habitat loss demonstrated through avoidance behavior. Caribou may cross roads less frequently than expected for a number of reasons, including an aversion to the physical barrier presented by a road and associated forest opening, vehicle traffic, or predation by humans. The effects of habitat fragmentation through habitat loss, avoidance, and the semipermeable barrier effects of roads should be considered in developing strategies to maintain woodland caribou populations in Alberta. Roads that act as semipermeable barriers to caribou movements may make the presence of caribou more predictable in space and time, and hence compromise the "spacing out" strategy that caribou adopt to reduce predation. The approach we have outlined in this paper is a useful method to quantify the effects of human developments acting as semipermeable barriers to animal movements and should be considered in the development of animal-movement models.
- Published
- 2002
6. Marine and freshwater centrohelid heliozoans (Haptista: Centroplasthelida) in Canada, including taxonomic revisions and descriptions of 22 new species and subspecies.
- Author
-
Nicholls, Kenneth H.
- Subjects
SUBSPECIES ,TERRITORIAL waters ,FRESH water ,FRESHWATER habitats ,SPECIES - Abstract
Canadian coastal waters of the Pacific Ocean and the Atlantic Ocean as well as inland freshwater habitats in Ontario were sampled for centrohelid heliozoans (free-living heterotrophic single-celled organisms) over a period of nearly five decades. More than 60 species and subspecies were revealed, including 1 Triangulopteris, 1 Raphidocystis, 2 Pseudoraphidocystis, 3 Raineriophrys, 4 Pseudoraphidiophrys, 12 Choanocystis, 15 Pterocystis, and 25 Acanthocystis taxa. Of these, 22 were officially named and described as new to science based primarily on the morphology of the siliceous scales that cover the cell. New species were compared with images and/or descriptions of close "relatives" to validate their new species assignments. New data on five species of Acanthocystis and one species of Choanocystis required revisions of their descriptive taxonomy that in some cases resulted in the splitting off of separate species or subspecies. Very little can be concluded about global distribution of centrohelid heliozoans, owing to the paucity of records. For many of the taxa reported here, previous records consist of just one or two findings from other parts of the world. One example is Choanocystis antarctica Tikhonenkov and Mylnikov, 2011 that was previously known only from Antarctic seawater, but is reported here from an Ontario softwater lake. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
7. Applying technical guidance from the USA for management of impacts of anthropogenic noise on wildlife in other countries: the Canadian context.
- Author
-
Wright, Andrew J., Moors-Murphy, Hilary B., and Yurk, Harald
- Subjects
MARINE mammals ,SOUND pressure ,FISHERIES ,NOISE ,GOVERNMENT agencies ,UNDERWATER noise - Abstract
Technical Guidance from the US National Marine Fisheries Service recommends Federal agencies use estimated thresholds for peak sound pressure levels and weighted cumulative sound exposure levels for the onset of permanent (and temporary) hearing threshold shifts in marine mammals. These dual metrics were developed to inform impact assessments within the US legal landscape. Despite its merits, the Technical Guidance contains uncertainties due to limited data on marine mammal hearing and auditory response to noise. The underlying assumptions about how representative existing data are for all marine mammal species also create limitations in the applicability of the Technical Guidance. These limitations warrant consideration before the Technical Guidance can be applied effectively in other jurisdictions with different legal standards. Using the Canadian legal framework as a working example, we found that many Canadian species are underrepresented in the dataset informing the Technical Guidance. The Technical Guidance also does not address all relevant noise impact types. Thus, the Technical Guidance alone cannot address all Canadian legal standards and, if the Technical Guidance is incorporated, some adjustments to the criteria within may be needed to meet the precautionary requirements of many Canadian legal standards. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
8. Short visits reveal consistent patterns of interyear and intercolony variation in seabird nestling diet and performance.
- Subjects
- *
SEA birds , *RHINOCEROS auklet , *BABY birds , *DIET - Abstract
To investigate the utility of short visits to seabird colonies to gauge nestling growth performance and diet, in four consecutive years from 1995 to 1998, the paper measures the nestling development and diet of rhinoceros auklets or cerorhinca monocerata at three colonies in British Columbia: Seabird Rocks, Triangle Island and SGaang Gwaii (Anthony Island).
- Published
- 2002
- Full Text
- View/download PDF
9. Two new species of encrusting sponge (Porifera, family Crellidae) from eastern Canada.
- Author
-
Goodwin, Claire, Dinn, Curtis, Nefedova, Ekaterina, Nijhof, Frauke, Murillo, Francisco Javier, and Nozères, Claude
- Subjects
SPONGES (Invertebrates) ,SPECIES ,DIVING - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2021
- Full Text
- View/download PDF
10. Estimating critical habitat based on year-round movements of the endangered Jefferson Salamander (Ambystoma jeffersonianum) and their unisexual dependents.
- Author
-
Van Drunen, S.G., Linton, J.E., Bogart, J.P., McCarter, J., Fotherby, H., Sandilands, A., and Norris, D.R.
- Subjects
HOME range (Animal geography) ,WILDLIFE conservation ,SALAMANDERS ,ENDANGERED species ,HABITATS ,SUMMER ,HABITAT conservation - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
11. Histological evidence of reproductive senescence in Atlantic herring (Clupea harengus).
- Author
-
Benoît, Hugues P., Benhalima, Kadra, and McDermid, Jenni L.
- Subjects
ATLANTIC herring ,FISH spawning ,SPAWNING ,EVOLUTIONARY theories ,GONADS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
12. Effects of linear features on resource selection and movement rates of wood bison (Bison bison athabascae).
- Author
-
DeMars, C.A., Nielsen, S.E., and Edwards, M.A.
- Subjects
AMERICAN bison ,HABITAT selection ,BISON ,FEATURE selection ,CARIBOU ,REINDEER ,PREDATORY animals ,CLEARCUTTING - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
13. Tree Swallow (Tachycineta bicolor) nest success and nestling growth near oil sands mining operations in northeastern Alberta, Canada.
- Author
-
Godwin, Christine M., Barclay, Robert M.R., and Smits, Judit E.G.
- Subjects
OIL sands ,BABY birds ,NESTS ,GASTROINTESTINAL contents ,DEGLUTITION ,FOOD quality - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2019
- Full Text
- View/download PDF
14. Postbreeding movement patterns and habitat use of adult Wood Frogs ( Lithobates sylvaticus) at urban wetlands.
- Author
-
Taylor, Murdoch E.D. and Paszkowski, Cynthia A.
- Subjects
WOOD frog ,WETLANDS ,AMPHIBIAN populations ,HABITATS ,AMPHIBIAN behavior ,AMPHIBIAN conservation ,URBANIZATION & the environment - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2018
- Full Text
- View/download PDF
15. An assessment of the efficacy of rub stations for detection and abundance surveys of Canada lynx ( Lynx canadensis).
- Author
-
Crowley, Shannon M. and Hodder, Dexter P.
- Subjects
LYNX ,LYNX (Genus) ,ANIMALS ,MAMMAL population estimates ,ZOOLOGICAL surveys ,ANIMAL behavior - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2017
- Full Text
- View/download PDF
16. Nematode parasites and leukocyte profiles of Northern Leopard Frogs, Rana pipiens: location, location, location.
- Author
-
Shutler, Dave, Gendron, Andrée D., Rondeau, Myriam, and Marcogliese, David J.
- Subjects
NORTHERN leopard frog ,LEUCOCYTES ,NEMATODES ,PHYSIOLOGICAL effects of pesticides ,WETLANDS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2015
- Full Text
- View/download PDF
17. Synchrony in the snowshoe hare ( Lepus americanus) cycle in northwestern North America, 1970-2012.
- Author
-
Krebs, Charles J., Kielland, Knut, Bryant, John, O'Donoghue, Mark, Doyle, Frank, McIntyre, Carol, DiFolco, Donna, Berg, Nathan, Carriere, Suzanne, Boonstra, Rudy, Boutin, Stan, Kenney, Alice J., Reid, Donald G., Bodony, Karin, Putera, Judy, Timm, Henry K., and Burke, Toby
- Subjects
GREAT horned owl ,SNOWSHOE rabbit ,LEPUS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
- Full Text
- View/download PDF
18. The living community inside the common periwinkle, Littorina littorea.
- Author
-
Buckland-Nicks, John, Chisholm, Sarah Ann, and Gibson, Glenys
- Subjects
COMMUNITIES ,LITTORINA ,HABITATS ,ENDOSYMBIOSIS ,MOLLUSKS ,PARASITISM ,COASTS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2013
- Full Text
- View/download PDF
19. Variation in diet of Semipalmated Sandpipers ( Calidris pusilla) during stopover in the upper Bay of Fundy, Canada.
- Subjects
SEMIPALMATED sandpiper ,STAGING areas (Birds) ,BIRD migration ,WINTERING of birds - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
20. Ribeiroia ondatrae causes limb abnormalities in a Canadian amphibian community.
- Author
-
Roberts, C.D. and Dickinson, T.E.
- Subjects
TREMATODA ,ABNORMALITIES in the anatomical extremities ,AMPHIBIANS ,MORTALITY - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
21. Molecular phylogeny of Gyrodactylus (Monogenea) parasitizing fishes in fresh water, estuarine, and marine habitats in Canada.
- Author
-
Gilmore, S.R., Cone, D.K., Lowe, G., King, S.K., Jones, S.R.M., and Abbott, C.L.
- Subjects
MOLECULAR phylogeny ,MONOGENEA ,ATLANTIC salmon ,MARINE habitats ,POLYMERASE chain reaction - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
22. Advances in insect physiology and endocrinology through genomics, peptidomics, and related technologies.
- Author
-
Orchard, I. and Lange, A. B.
- Subjects
NEUROPEPTIDES ,ENDOCRINOLOGY ,MOLECULAR genetics ,DIURESIS ,GENOMES - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2012
- Full Text
- View/download PDF
23. Changes in relative abundance of snowshoe hares () across a 265-year gradient of boreal forest succession.
- Author
-
Hodson, James, Fortin, Daniel, and Bélanger, Louis
- Subjects
FOREST canopy gaps ,HARES ,FOREST management ,SNOWSHOE rabbit ,TAIGAS ,REPRODUCTION - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
- Full Text
- View/download PDF
24. Conservation of caribou (Rangifer tarandus) in Canada: an uncertain future.
- Author
-
Festa-Bianchet, M., Ray, J.C., Boutin, S., Côté, S.D., and Gunn, A.
- Subjects
CARIBOU ,REINDEER ,WILDLIFE conservation ,ANIMAL ecology - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
- Full Text
- View/download PDF
25. Fluctuations in lemming populations in north Yukon, Canada, 2007-2010.
- Author
-
Krebs, Charles J., Reid, Donald, Kenney, Alice J., and Gilbert, Scott
- Subjects
LEMMINGS ,COLLARED lemming ,MICROTUS oeconomus ,BROWN lemming ,ANIMAL population density - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2011
- Full Text
- View/download PDF
26. Habitat selection at multiple spatial scales in Northern Map Turtles (Graptemys geographica).
- Author
-
Carrière, M.-A. and Blouin-Demers, G.
- Subjects
HABITAT selection ,HABITATS ,ANIMAL ecology ,TURTLES ,COMMON map turtle - Abstract
Understanding habitat use of declining species is essential for their management and successful recovery. We examined habitat selection at multiple spatial scales by Northern Map Turtles (Graptemys geographica (Le Sueur, 1817)), a species at risk, in the St. Lawrence Islands National Park, Ontario, Canada. At the scale of the home range, Map Turtles generally avoided deep water (>2 m) and selected home ranges in waters <1 m deep. Importantly, turtles used home ranges with significantly more natural than developed shoreline. At the scale of the location, adult females used deep water more often and males preferred areas with surface cover. Management efforts should implement regulations concerning further shoreline development. La gestion et la récupération réussie des espèces en déclin nécessitent une compréhension de leur utilisation de l'habitat. Nous examinons la sélection de l'habitat à plusieurs échelles spatiales chez la tortue géographique (Graptemys geographica (Le Sueur, 1817)), une espèce vulnérable, dans le parc national des Îles-du-Saint-Laurent, Ontario, Canada. À l'échelle du domaine vital, les tortues géographiques évitent généralement les eaux profondes (>2 m) et choisissent des domaines vitaux dans des eaux de <1 m de profondeur. Ce qui est plus important, les tortues utilisent des domaines vitaux qui possèdent significativement plus de ligne de rivage naturelle que modifiée. À l'échelle du site, les femelles adultes utilisent les eaux profondes plus fréquemment et les mâles préfèrent les zones qui possèdent un couvert en surface. Les efforts de gestion devraient inclure la mise en vigueur de règlements concernant les modifications futures des rivages. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
27. Fish and harlequin ducks compete on breeding streams.
- Author
-
LeBourdais, S. V., Ydenberg, R. C., and Esler, D.
- Subjects
BREEDING ,FISHES ,DUCKS ,RIVERS ,BENTHIC animals - Abstract
We investigated interactions among harlequin ducks (Histrionicus histrionicus (L., 1758)), fish, and their shared aquatic insect prey. We measured flow variability, benthic aquatic prey abundance, fish presence, and breeding density of harlequins on eight rivers in the Southern Coast Mountain Range in British Columbia, Canada, in 2003 and 2004. Rivers with lower flow variability had higher abundance of aquatic insects. Densities of harlequins and fish presence on the rivers were both significantly and positively related to insect abundance, but path analysis revealed a strong negative correlation between them. We interpret this as an indirect interaction between harlequins and fish mediated by anti-predator behaviour of insects in the presence of fish, which reduces insect availability, rather than as a reduction in the abundance of aquatic insects through consumption by fishes. We hypothesize that the ongoing and widespread introduction of fish into historically fishless waters throughout North America may have contributed to the current low productivity and recruitment measured in populations of harlequins by reducing quality of breeding habitat. Nous étudions les interactions entre les arlequins plongeurs (Histrionicus histrionicus (L., 1758)), les poissons et les insectes aquatiques qu’ils utilisent conjointement comme proies. Nous avons mesuré la variabilité du débit, l’abondance des proies aquatiques benthiques, la présence de poissons et la densité des arlequins plongeurs en reproduction dans huit rivières de la chaîne de montagnes de la côte sud de la Colombie Britannique, Canada, en 2003 et 2004. Les rivières à débit moins variable ont de plus fortes abondances d’insectes aquatiques. Il y a une relation significative et positive entre les densités des arlequins plongeurs et la présence de poissons, d’une part, et l’abondance des insectes, d’autre part, mais une analyse des coefficients de direction montre une forte corrélation négative entre ces deux variables. Nous interprétons ce phénomène comme une interaction indirecte entre les arlequins plongeurs et les poissons qui s’explique par le comportement anti-prédateur des insectes en présence des poissons, ce qui réduit la disponibilité des insectes, plutôt que par une réduction de l’abondance des insectes aquatiques à cause de la consommation par les poissons. Nous posons l’hypothèse selon laquelle les introductions courantes et répandues de poissons dans des eaux historiquement sans poissons dans toute l’Amérique du Nord peuvent avoir contribué à la productivité et au recrutement faibles mesurés actuellement chez les populations d’arlequins plongeurs en réduisant la qualité des habitats de reproduction. [ABSTRACT FROM AUTHOR]
- Published
- 2009
- Full Text
- View/download PDF
28. Habitat selection by black bears in an intensively logged boreal forest.
- Author
-
Ouellet, Jean-Pierre, Courtois, Réhaume, Fortin, Daniel, and Brodeur, Vincent
- Subjects
TAIGAS ,BLACK bear ,ANIMAL ecology ,HABITAT selection ,FORESTS & forestry - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2008
- Full Text
- View/download PDF
29. The case of the blood-covered egg: ectoparasite abundance in an arctic goose colony.
- Author
-
Harriman, V. B., Alisauskas, R. T., and Wobeser, G. A.
- Subjects
GEESE ,EGGS ,FLEAS ,NESTS ,COLONIAL birds ,HABITATS ,CERATOPHYLLUS ,PARASITES - Abstract
Since 1991, blood-covered eggs have been noted in nests of Ross’s (Chen rossii (Cassin, 1861)) and lesser snow (Chen caerulescens caerulescens (L., 1758)) geese at the Karrak Lake colony, Nunavut, Canada. Fleas (Ceratophyllus vagabundus vagabundus (Boheman, 1866)) were subsequently observed to be associated with goose nests containing eggs covered with dried blood. We examined prevalence of blood presence on goose eggs and extent of egg coverage with blood in goose nests from 2001 to 2004. Flea abundance in nests was estimated in 2003 and 2004, and was strongly correlated with the proportion of goose egg surface covered by blood, suggesting that degree of blood coverage was a suitable index of flea abundance. Extent of blood fluctuated annually and was correlated with both host characteristics and host habitat factors. Nest bowls used by geese in previous years contained more fleas than did new nest bowls, and fleas were more abundant in older areas of the colony. Flea abundance increased with goose clutch size and was highest in rock and birch habitats. Ceratophyllus vagabundus vagabundus appears to be a new parasite of geese at Karrak Lake; flea abundance may change in response to increased availability of favorable habitat, which is expected if local climate warms. Depuis 1991, on observe des oeufs recouverts de sang dans les nids des oies de Ross (Chen rossii (Cassin, 1861)) et des petites oies des neiges (Chen caerulescens caerulescens (L., 1758)) dans la colonie du lac Karrak, Nunavut, Canada. On a ensuite associé la présence de puces (Ceratophyllus vagabundus vagabundus (Boheman, 1866)) aux nids d’oies contenant des oeufs recouverts de sang séché. Nous avons examiné la prévalence de la présence de sang sur les oeufs d’oies et l’étendue de la couverture de sang dans les nids d’oies de 2001 à 2004. Nous avons estimé l’abondance des puces dans les nids en 2003 et 2004; celle-ci est en forte corrélation avec la proportion de la surface des oeufs d’oies recouverte de sang, ce qui laisse penser que l’importance de la couverture de sang est un bon indice de l’abondance des puces. L’importance du sang varie d’une année à l’autre et est en corrélation avec tant les caractéristiques de l’hôte que les facteurs de l’habitat de l’hôte. Les cuvettes de nidification utilisées les années antérieures contiennent plus de puces que les nouvelles cuvettes de nidification et les puces sont plus abondantes dans les zones plus anciennes de la colonie. L’abondance des puces augmente en fonction de la taille de la couvée des oies et elle est maximale dans les habitats de pierres et de bouleaux. Ceratophyllus vagabundus vagabundus semble être un nouveau parasite des oies au lac Karrak; on s’attend à ce que l’abondance des puces change en réaction à la disponibilité accrue d’habitats favorables prévue dans le cas d’un réchauffement du climat local. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
30. Chemical, thermal, and physical properties of sites selected for overwintering by northern wood turtles (Glyptemys insculpta).
- Author
-
Greaves, W. F. and Litzgus, J. D.
- Subjects
TURTLES ,GLYPTEMYS ,HIBERNACULA (Animal habitations) ,WINTER ,OXYGEN ,WATER temperature ,RIVER sediments ,RIVERS - Abstract
Northern ectotherms must seek refuge from winter conditions for a large portion of their annual activity cycle. The objective of this study was to quantify physical properties of overwintering sites selected by wood turtles (Glyptemys insculpta (LaConte, 1830)) at the species’ northern range limit. We mapped all structural features (e.g., root balls and log jams), water depth, and sediment types along a 1.5 km stretch of river that was available to turtles outfitted with radio transmitters (N = 8) during winter. Temperature selection was assessed by comparing thermal profiles from data loggers on turtles and temperature stations within the river and other riparian habitats (e.g., ephemeral pools and oxbows). Dissolved oxygen (DO) was measured at each temperature station and turtle location. Wood turtles overwintered in the river, which was colder (~0 °C), had more stable temperatures, and provided higher DO (12.64 ppm) compared with adjacent habitats. Some turtles selected structured refuges for overwintering. Winter movements were not related to temperature or DO, but may be related to maintaining a certain distance from shore and water depth to protect against accidental relocations during winter. We discuss hibernacula as potential factors limiting the northern distribution of wood turtles, a species at risk in Canada. Les ectothermes nordiques doivent trouver un refuge contre les conditions hivernales durant une partie importante de leur cycle annuel d’activités. L’objectif de notre étude est de mesurer les propriétés physiques des sites d’hivernage choisis par les tortues des bois (Glyptemys insculpta (LeConte, 1830)) à la limite boréale de la répartition de l’espèce. Nous avons cartographié tous les éléments structuraux (par ex., boules de racines et embâcles), la profondeur de l’eau et les types de sédiments sur une section de 1,5 km de rivière disponible à des tortues (N = 8) porteuses de radiotransmetteurs pendant l’hiver. La sélection de la température a été évaluée en comparant les profils de températures sur les enregistreuses fixées aux tortues et ceux des stations d’enregistrement dans la rivière et dans les autres habitats de la rive (par ex., les étangs temporaires et les bras morts). Nous avons mesuré l’oxygène dissous (DO) à chaque station d’enregistrement thermique et à chaque emplacement habité par une tortue. Les tortues des bois passent l’hiver dans la rivière qui présente des températures plus froides (~0 °C), mais plus stables et des concentrations de DO plus grandes (12,64 ppm) que les habitats adjacents. Quelques tortues ont choisi des refuges dans des structures pour passer l’hiver. Les déplacements en hiver ne sont pas reliés à la température, ni à la concentration de DO, mais s’expliquent peut-être par le besoin de maintenir une certaine distance de la berge et une certaine profondeur d’eau afin d’éviter les déplacements accidentels pendant l’hiver. Nous discutons des hibernacles comme facteurs potentiels qui peuvent limiter la répartition vers le nord de la tortue des bois, une espèce à risque au Canada. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
31. Population structure and mantle display polymorphisms in the wavy-rayed lampmussel, Lampsilis fasciola (Bivalvia: Unionidae).
- Author
-
Zanatta, David T., Fraley, Stephen J., and Murphy, Robert W.
- Subjects
DNA ,FASCIOLA ,HUMAN ecology ,GENETIC polymorphisms ,WILDLIFE conservation ,ENDANGERED species ,GENETIC research ,RADIOACTIVE pollution of water ,RIVERS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2007
- Full Text
- View/download PDF
32. Extinction, colonization, and distribution patterns of common eider populations nesting in a naturally fragmented landscape.
- Author
-
Robertson, G.J., Montevecchi, W.A., and Chaulk, K.G.
- Subjects
EIDER ,BIOLOGICAL extinction ,COLONIZATION (Ecology) ,FRAGMENTED landscapes ,ECOLOGY ,ISLANDS ,BIRDS ,REPRODUCTIVE isolation - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2006
- Full Text
- View/download PDF
33. Common vole (Microtus arvalis) population sex ratio: biases and process variation.
- Author
-
Bryja, Josef, Nesvadbová, Jiřina, Heroldová, Marta, Jánová, Eva, Losík, Jan, Trebatická, Lenka, and Tkadlec, Emil
- Subjects
MICROTUS arvalis ,VOLES ,MICE ,ANIMAL populations ,ANIMAL offspring sex ratio ,SEXUAL dimorphism in animals ,SEX differences (Biology) ,ZOOLOGY - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
34. Female wolverine (Gulo gulo) reproduction: reproductive costs and winter food availability.
- Author
-
Persson, Jens
- Subjects
GULO ,WOLVERINE ,REPRODUCTION ,ANIMAL nutrition ,FOOD supply ,DIETARY supplements ,WINTER ,ZOOLOGY - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
35. Resource allocation in fledglings of the rhinoceros auklet under different feeding conditions: an experiment manipulating meal size and frequency.
- Author
-
Takenaka, Makiko, Niizuma, Yasuaki, and Watanuki, Yutaka
- Subjects
RHINOCEROS auklet ,AMMODYTES ,PERCIFORMES ,RESOURCE allocation ,ANIMAL nutrition ,ZOOLOGY - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
36. Habitat occupancy patterns of a forest dwelling songbird: causes and consequences.
- Author
-
Doran, Patrick J. and Holmes, Richard T.
- Subjects
DENDROICA ,AUSTRALASIAN warblers ,SONGBIRDS ,ANIMAL migration ,ANIMAL behavior ,FOREST ecology ,HABITATS ,ZOOLOGY - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
37. Overcoming environmental and morphological constraints: egg size and pelvic kinesis in the smallest tortoise, Homopus signatus.
- Author
-
Hofmeyr, M. D., Henen, B. T., and Loehr, V. J. T.
- Subjects
TESTUDINIDAE ,TURTLES ,ANIMAL morphology ,BODY size ,EGGS ,CLIMATOLOGY ,ACCLIMATIZATION ,ZOOLOGY - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
38. The fall and rise of bison populations in Wood Buffalo National Park: 1971 to 2003.
- Author
-
Bradley, Mark and Wilmshurst, John
- Subjects
BISON ,DEMOGRAPHIC change ,TUBERCULOSIS ,BRUCELLOSIS ,SURVIVAL behavior (Animals) ,REPRODUCTION ,PREDATION - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
39. Competition potential between sympatric woodland caribou and wood bison in southwestern Yukon, Canada.
- Author
-
Fischer, Lisa A. and Gates, C. Cormack
- Subjects
WOODLAND caribou ,CARIBOU ,WOOD bison ,BISON ,RESOURCE partitioning (Ecology) ,HABITAT selection ,COMPETITION (Biology) - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
40. The quantitative effects of population density and winter weather on the body condition of white-tailed deer (Odocoileus virginianus) in Nova Scotia, Canada.
- Author
-
Garroway, Colin J. and Broders, Hugh G.
- Subjects
WHITE-tailed deer ,POPULATION density ,WINTER ,WEATHER ,SURVIVAL analysis (Biometry) ,SURVIVAL behavior (Animals) - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2005
- Full Text
- View/download PDF
41. Movements and distribution of northern bottlenose whales, Hyperoodon ampullatus, on the Scotian Slope and in adjacent waters.
- Author
-
Wimmer, Tonya and Whitehead, Hal
- Subjects
BEAKED whales ,HABITATS ,ANTS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2004
- Full Text
- View/download PDF
42. Butterfly assemblages along a human disturbance gradient in Ontario, Canada.
- Author
-
Hogsden, K.L. and Hutchinson, T.C.
- Subjects
BUTTERFLIES ,ANIMAL species ,URBAN ecology ,ZOOGEOGRAPHY ,ANIMAL behavior - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2004
- Full Text
- View/download PDF
43. Winter habitat selection by white-tailed deer on Anticosti Island 2: relationship between deer density from an aerial survey and the proportion of balsam fir forest on vegetation maps.
- Author
-
Potvin, François and Boots, Barry
- Subjects
DEER wintering ,ODOCOILEUS ,BALSAM fir ,FORESTS & forestry - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2004
- Full Text
- View/download PDF
44. Scat detection dogs in wildlife research and management: application to grizzly and black bears in the Yellowhead Ecosystem, Alberta, Canada.
- Author
-
Wasser, Samuel K., Davenport, Barbara, Ramage, Elizabeth R., Hunt, Kathleen E., Parker, Margaret, Clarke, Christine, and Stenhouse, Gordon
- Subjects
WILDLIFE research ,GRIZZLY bear ,BLACK bear ,DOGS ,ECOSYSTEM management - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2004
- Full Text
- View/download PDF
45. Comparison among three approaches to evaluate winter habitat selection by white-tailed deer on Anticosti Island using occurrences from an aerial survey and forest vegetation maps.
- Author
-
Potvin, François, Boots, Barry, and Dempster, Alastair
- Subjects
WHITE-tailed deer ,HABITATS ,BALSAM fir ,FIR - Abstract
Habitat-selection analysis involves a comparison between the proportions of different cover types that are used by the animal and the proportions that are available. Telemetry locations or animal occurrences (e.g., from aerial surveys) can provide information on habitat utilization. With telemetry data, a classical approach involves computing habitat use at the individual location sites or inside fixed circle buffers applied to the sites. We used this approach (200 m radius circles) on data from a systematic aerial survey on Anticosti Island, where 260 groups of white-tailed deer (Odocoileus virginianus) (374 animals) were counted in a 270-km² block. We compared the selection indices obtained from site occurrences with those of two approaches that define areas of high intensity (animal concentrations): 50% fixed kernels (0.5-2 km bandwidth) and the local K function (0.5-2 km distance). The results were very consistent among the three sets of approaches, with the same cover types generally identified as those having the highest or lowest indices. White-tailed deer preferred forest stands where balsam fir (Abies balsamea) was present as high regeneration or was dominant in the tree layer (>50% basal area) and stands at the regeneration stage. In the studied landscape, there seems to be a wide range of spatial scales where the selection process can be analyzed from aerial survey data. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
46. Another one bites the dust: Does incisor-arcade size affect mass gain and survival in grazing ungulates?
- Author
-
von Hardenberg, Achaz, Shipley, Bill, and Festa-Bianchet, Marco
- Subjects
BIGHORN sheep ,INCISORS ,BODY size - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2003
- Full Text
- View/download PDF
47. Relationships among grizzly bears, highways, and habitat in the Banff-Bow Valley, Alberta, Canada.
- Author
-
Chruzscz, Bryan, Clevenger, Anthony P., Gunson, Kari C., and Gibeau, Michael L.
- Subjects
GRIZZLY bear ,SPATIAL behavior in animals ,ANIMAL behavior - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2003
- Full Text
- View/download PDF
48. Shorebirds, mud snails, and Corophiumvolutator in the upper Bay of Fundy, Canada: predicting bird activity on intertidal mud flats.
- Author
-
Hamilton, Diana J., Barbeau, Myriam A., and Diamond, Antony W.
- Subjects
SHORE birds ,HABITATS - Abstract
Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2003
- Full Text
- View/download PDF
49. Escalated aggression in interpopulation brook trout dyads: evidence for behavioural divergence.
- Author
-
Dunbrack, Robert and Clarke, Lynn
- Subjects
BROOK trout ,ANIMAL aggression - Abstract
The "communication-failure" hypothesis states that individuals whose agonistic displays deviate from the population norm are selected against because of the greater likelihood of their becoming involved in escalated contests. A corollary of this hypothesis is that the level of aggression in dyadic (pairwise) contests over resources is predicted to be higher the greater the behavioural divergence between the two contestants. Display divergence between two contestants from different populations should exceed that in intrapopulation dyads, consequently this prediction can be tested by comparing levels of aggression in contests between interpopulation dyads with those in contests between intrapopulation dyads. We carried out such a test using brook trout (Salvelinus fontinalis) from two isolated populations in eastern Newfoundland. In initial encounters, the nipping rate (a measure of aggressiveness) of individuals from one of these populations was significantly higher in interpopulation dyads than in intrapopulation dyads. These results are consistent with the communication-failure hypothesis, as well as with the view that behavioural assessment, using low-cost stereotypic displays, reduces the cost of interactions over resources for both contestants. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
50. Terrestrial trophic dynamics in the Canadian Arctic.
- Author
-
Krebs, Charles J., Danell, Kjell, Angerbjörn, Anders, Agrell, Jep, Berteaux, Dominique, Bråthen, Kari Anne, Danell, Öje, Erlinge, Sam, Fedorov, Vadim, Fredga, Karl, Hjältén, Joakim, Högstedt, Göran, Jónsdóttir, Ingibjörg S., Kenney, Alice J., Kjellén, Nils, Nordin, Torgny, Roininen, Heikki, Svensson, Mikael, and Tannerfeldt, Magnus
- Subjects
TROPISMS ,TUNDRA ecology - Abstract
The Swedish Tundra Northwest Expedition of 1999 visited 17 sites throughout the Canadian Arctic. At 12 sites that were intensively sampled we estimated the standing crop of plants and the densities of herbivores and predators with an array of trapping, visual surveys, and faecal-pellet transects. We developed a trophic-balance model using ECOPATH to integrate these observations and determine the fate of primary and secondary production in these tundra ecosystems, which spanned an 8-fold range of standing crop of plants. We estimated that about 13% of net primary production was consumed by herbivores, while over 70% of small-herbivore production was estimated to flow to predators. Only 9% of large-herbivore production was consumed by predators. Organization of Canadian Arctic ecosystems appears to be more top-down than bottom-up. Net primary production does not seem to be herbivore-limited at any site. This is the first attempt to integrate trophic dynamics over the entire Canadian Arctic. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.