Humans have introduced bullfrogs, bullhead catfish, bass, green sunfish, crayfish, and others, which prey upon larvae, eggs, and adult arroyo toads. These exotic species have a substantial impact on toad populations and may have contributed to regional extinctions. The droughts that typify the arid region where the arroyo toad lives are the most significant naturally occurring threat to the arroyo toad's survival. Most remaining arroyo toad habitats are ephemeral they don't flow or hold water year-round. Droughts can dry up these waterways early in the year, killing eggs or larvae before they have a chance to metamorphose.
Reduced populations are also less resilient to extreme, destructive events.
For example, a fire on upper Sespe Creek in 1991 destroyed 15 known breeding pools by causing siltation. In the past, when the toads occupied the full lengths of many streams, numerous populations could repopulate depleted streams. Today, however, with fewer, smaller populations, the entire species faces a greater threat of being wiped out by natural or human-caused disasters. The arroyo toad was listed so recently that few major steps have been taken to conserve the species. No major regional or watershed-level conservation efforts have been initiated to protect the arroyo toad and its habitat.