Over the past several decades, many amphibian species
have undergone population declines, range reductions,
or extinction (Blaustein et al. 1994a; Blaustein et al.
1994b; Blaustein and Wake 1990, 1995; Green 1997;
Wake 1998; Alford and Richards 1999; Carey et. al.
1999; Houlahan et al. 2000). Although some declines
can be explained as natural population fluctuations,
and a few are unexplained, most declines and disappearances
are clearly the result of human activities –
primarily habitat loss or degradation as the result of
land conservation, urbanization, or development (Wake
1991; Vial and Saylor 1993; Corn 1994; Blaustein
and Wake 1995; Pechmann and Wake 1997; Lehtinen
et al. 1999). Other factors, including the introduction
of exotic vertebrate species, infection with viral,
fungal, bacterial, or invertebrate pathogens, harvesting
by humans, road mortality and habitat fragmentation
also have contributed to amphibian declines. (Exotic
species: Hayes and Jennings 1986; Bradford 1989;
Gamradt and Kats 1996; Kiesecker and Blaustein
1997, 1998; Lawler et al. 1999; Knapp and Matthews
2000); pathogens: Carey 1993; Blaustein et al.
1994c; Laurance et al. 1996; Hecnar and M’Closkey
1997b; Kiesecker and Blaustein 1997; Speare et al.
1997; Berger et al. 1998; Carey et al. 1999; Johnson
et al. 1999; Taylor et al. 1999; Carey 2000; harvesting:
Blaustein and Wake 1995; road mortality: van Gelder
1973; Fahrig et al. 1995; habitat fragmentation:
Blaustein et al. 1994b; deMaynadier and Hunter
1995; Corn and Fogleman 1984; Sjögren 1991; Gibbs
1998a ; Sjögren-Gulve and Ray 1998; Lehtinen et al.
Davis, T.M.. 2002. Research Priorities for the Management of the Western Toad (Bufo boreas) in British Columbia. Ministry of Water, Land and Air Protection. Wildlife Working Report. WR106