PARENT SESSION
Poster Session #69: Animal Ecology.
Friday, August 9. Presentation from 8:00 AM to 9:30 AM. Exhibit Hall B & C, TCC

Patterns of age, size, and growth in Canadian toad populations based on skeletochronology.

PASZKOWSKI, CYNTHIA^*,1, EATON, BRIAN¹, ¹ University of Alberta, Edmonton, Alberta, Canada

ABSTRACT- Formerly, the Canadian toad (Bufo hemiophrys) was widely distributed across eastern Alberta with a range stretching 1300 km north to south. Since the 1980s, the species has nearly disappeared in the grasslands of southern Alberta, but remains relatively common in the northern forests. Demographic information on Canadian toad populations, needed to develop conservation strategies for the species, is sparse. We used skeletochronology based on phalangeal bones to determine size-at-age relationships and longevity, and to compare demographic patterns among southern and northern populations. We aged 220 Canadian toads that were captured and released during field studies or were from museum collections. One unique sample consisted of an entire breeding aggregation of 78 animals collected at a single site in southern Alberta in 1962. Populations differed in size-at-age relationships at both small and large geographic scales. Moreover, individuals of the same size and sex from the same population varied substantially in age. Canadian toads are long-lived with individuals > 8 years old encountered at several sites. Longevity, coupled with high fecundity and the persistence of boreal populations despite natural inter-annual variation in breeding success, suggests that remnant Canadian toad populations in southern Alberta may have the capacity to recover if appropriate wetlands and adjacent terrestrial habitats are restored.

KEY WORDS: Amphibians, Aging Techniques, Bufo hemiophrys, Conservation