Ability to Respond Total:9 / 25Ability to Respond = ( Ease of Response + Tools in Place )
Confidence:High
Confidence Notes:
Impact
Spread
Notes
Score
Spread Rate
Although typically limited to permanent water bodies, due to their presence as a human food source, this species has been spread to temperate climates around the world. Once introduced to a new area they are difficult to extirpate and are highly prolific.
5
Spread Amount
The bullfrog is native to eastern North America with a natural range extending as far as Oklahoma and Kansas. Bullfrogs have been introduced to all of the Pacific states, including Hawaii, where it outcompetes native species of amphibians.
5
Damage
Notes
Score
Ecological
Voracious predator with broad feeding range, predates on and competes with native herpetofauna and other species; spreads chytrid fungus and other diseases; larvae can significantly impact benthic algae, and thus disrupt aquatic community structures.
5
Agricultural
0
Infrastructure
0
Cultural
The bullfrog greatly diminishes biological diversity and outcompetes and consumes many invasive species that we work to protect. Also, Bullfrog control plans for any new manmade water impoundments is an additional barrier to developing private properties.
3
Health
Implicated vector of leptospirosis
1
Benefit
Notes
Score
Ecological
Bullfrogs can be an important item of prey to many species of birds, mammals, and fish.
2
Agricultural
North American bullfrogs help to control insect pests. but in areas of California, bullfrogs are driving other frog populations to extinction that likely served similar ecological roles.
1
Infrastructure
Bullfrogs do well with changes in the environment that have occurred due to human modification, and are becoming increasingly common in areas modified by humans. Bullfrogs have a much higher critical thermal maximum than most other frogs, meaning that they are able to thrive in higher water temperatures.
0
Cultural
Cultivated world-wide as a popular food and targeted as a sport species by outdoors persons. The chorus of the Bullfrog also has a cultural nostalgia in rural cultures and often serves as a gateway species for youth naturalists.
3
Health
Used as a medical research animal and as a specimen for dissection in many schools across the world.
1
Total
12
Ability to Respond
Ease of Response
Notes
Score
Detection
Usually can be easily seen and heard during warm nights during their summer breeding season. Bullfrogs prefer warm weather and will hibernate buy burring itself into the mud in a small cave-like structure during cold weather.
3
Control
Repeated effort within a limited area; culling metamorphs in fall is the most effective method to reduce the population growth rate.
3
Tools in Place
Notes
Score
Entry
Widely distributed via unknowing public, aquaculture, fishermen, and the aquarium trade. Increased efforts in public education could help, but success of those efforts is unknown.
1
Control
Control options are limited because this species is regulated as a game species by CDFW. Three legal forms of take exists: 1) a sport fishing license (frogs cannot be wasted), 2) Form 1739 (draining, seining, and chemical), Scientific Collection Permit
1
Outreach
Low public awareness of negative impacts to other sensitive species. Work to increase popularity as a game species (to increase take) may backfire to increased spread.
