Bullfrog (Rana catesbeiana)
In
our area, bullfrogs have spread widely along the vicinity of the lower San Pedro
River, but mostly in artificial ponds. They have only recently been seen breeding
or in many numbers along the River itself. They are present near Bingham Cienega
and Redfield Canyon, and well to the south around Benson and St. David (an area
strongly dominated by non-native fish, frogs, and crayfish). But so far Hot Springs
Canyon and Paige Creek remain the province of the Lowland Leopard Frog (Rana
yavapaiensis), a native species which has been largely eliminated where exotic
aquatic species are strongly present. (See Philip Rosen and Cecil Schwalbe, "Widespread
effects of introduced species on reptiles and amphibians in the Sonoran Desert
Region", in Tellman op.cit., especially pp. 230-38 and figure 12.6.) Thanks
to the accompanying photograph (adapted from Collins, see citation on main Invasive
Animals page), our Associates should be able to distinguish these invaders from
our own Sonoran
Desert Toads. For further information on Bullfrogs, see this link:
http://biology.usgs.gov/s+t/noframe/x188.htm