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Speirseopteris orbiculata gen. et sp. nov. (Thelypteridaceae), a derived fossil filicalean from the Paleocene of western North America.
Download2006
Stockey, R.A., Rothwell, G.W., Lantz, T.C.
An apparently exindusiate filicalean fern with radial sori, sporangia with a vertical annulus, and monolete spores occurs in Paleocene sediments ca. 57 million years old of central Alberta, Canada. Specimens are preserved as coalified compressions and show features of frond morphology and...
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Temperature-dependent Allee effects in a stage-structured model for Bythotrephes establishment
Download2011-01-01
Young, J. D., Yan, N. D., Lewis, Mark A., Wittmann, M. J.
Whether the invasive freshwater cladoceran Bythotrephes longimanus can establish after introduction into a water body depends on several biotic and abiotic factors. Among these, water temperature is important because both development rates and mode of reproduction (parthenogenetic or sexual) in...
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Unusual predation attempts of polar bears on ringed seals in the southern beaufort sea: Possible significance of changing spring ice conditions
Download2008
Richardson, E., Stirling, I., Thiemann, G.W., Derocher, A.E.
In April and May 2003 through 2006, unusually rough and rafted sea ice extended for several tens of kilometres offshore in the southeastern Beaufort Sea from about Atkinson Point to the Alaska border. Hunting success of polar bears (Ursus maritimus) seeking seals was low despite extensive...