Stomach contents from invasive American bullfrogs Rana catesbeiana (= Lithobates catesbeianus) on southern Vancouver Island, British Columbia, Canada

Invasive alien American bullfrog populations are commonly identified as a pernicious influence on the survival of native species due to their adaptability, proliferation and consequent ecological impacts through competit
Invasive alien American bullfrog populations are commonly identified as a pernicious influence on the survival of native species due to their adaptability, proliferation and consequent ecological impacts through competition and predation. However, it has been difficult to determine conclusively their destructive influence due to the fragmentary and geographically dispersed nature of the historical database. An expanding meta-population of invasive American bullfrogs, Rana catesbeiana (= Lithobates catesbeianus), became established on southern Vancouver Island, British Columbia, Canada in the mid- to late 1980s. An on-going bullfrog control program begun in 2006 offered a unique opportunity to examine the stomach contents removed from 5,075 adult and juvenile bullfrogs collected from 60 sites throughout the active season (April to October). Of 15 classes of organisms identified in the diet, insects were numerically dominant, particularly social wasps and odonates (damselflies and dragonflies). Seasonality and site-specific habitat characteristics influenced prey occurrence and abundance. Native vertebrates in the diet included fish, frogs, salamanders, snakes, lizards, turtles, birds, and mammals, including some of conservation concern. Certain predators of bullfrog tadpoles and juveniles are commonly preyed upon by adult bullfrogs, thereby suppressing their effectiveness as biological checks to bullfrog population growth. Prey species with antipredator defences, such as wasps and sticklebacks, were sometimes eaten in abundance. Many prey species have some type of anti-predator defence, such as wasp stingers or stickleback spines, but there was no indication of conditioned avoidance to any of these. Results from this study reinforce the conclusion that, as an invasive alien, the American bullfrog is an opportunistic and seemingly unspecialized predator that has a uniquely large and complex ecological footprint both above and below the water surface. 
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Metadaten
Author:Kevin Jancowski, Stan A. Orchard
URN:urn:nbn:de:hebis:30:3-323746
DOI:http://dx.doi.org/10.3897/neobiota.16.3806
Parent Title (English):NeoBiota
Document Type:Article
Language:English
Date of Publication (online):2013/11/21
Date of first Publication:2013/03/13
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2013/11/21
Tag:Bullfrog; Lithobates catesbeianus; Rana catesbeiana; diet; invasive species; predation
Issue:16
Pagenumber:21
First Page:17
Last Page:37
HeBIS PPN:363171452
Dewey Decimal Classification:590 Tiere (Zoologie)
Sammlungen:Sondersammelgebiets-Volltexte
Zeitschriften / Jahresberichte:NeoBiota 16
Journal: Dazugehörige Zeitschrift anzeigen
Licence (German):License LogoCreative Commons - Namensnennung 3.0

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