In the picture below is a cane toad (Bufo marinus). Cane toads are invasive in many countries around the world. They were introduced as pest control to protect sugar cane crops, but never did the job they were expected too.
Negative effects on frogs:
Worse to frogs than the constant threat of predation, is the constant and worsening threat of habitat lose, diseases, parasites, chytrid fungus, bacteria, introduced species, local environmental climate change, roads, ranavirus, pet trade, illegal export for collectors, agricultural chemical nutrient runoff, poisoning from pesticides, herbicides, insecticides…the list goes on. Many frog deformities are caused by parasites and the 3 –icides: pesticides, herbicides, and insecticides. And, what else is bad is these causes of negative ecological impacts on frog populations can be traced one way or another back to humans. In some cases we do not mean to do this to frogs, but it happens. And in other cases some individuals do for their own short term gain. For example, Russian authorities catch Chinese poachers who will knowingly poor toxic pesticides, which kill off entire ecosystems instantly, into Russian rivers and then collect and sell the resulting dead frogs. An example of accidental harm to frogs is individuals who try to save live frogs by buying them from grocery stores and releasing them into nearby water sources or by releasing their own pet frogs. The problem with that though, is these frogs most likely have fungal infections or other diseases obtained from poorly kept living conditions. Once released, they infect local native frog species with these diseases.
One really bad frog fungus is called chytrid. Chytrid is found to have infected African clawed frog species, but without actually harming these species. The problem is before this fungi was known the clawed frogs were exported throughout the world, and the fungus has spread to many other frog species. Unfortunately for all other frog species the fungus does great harm by attacking the keratin in the skin, and has caused many frog fatalities. And it is a hardy little fungus too, whose spores can last forever in water bodies, even after the water is gone.
It was not until the 1989 First World Congress of Herpetology that scientists first realized an epidemic of frog disappearances and extinctions was occurring. Sure, species naturally go extinct over time, but what is happening in our modern world is not natural. 5, 19, and 100s. Those are the numbers of frog species known to be extinct, disappeared and very likely extinct, and on the vary verge of extinction, in modern times. It is now up to governments around the world to take action.
Negative effects from frogs:
Frogs are not the only ones affected ecologically. Sometimes they can have a negative effect as well. Known cases come from introduced species such as the cane toad, B.marinus, and the American bullfrog, R. catesbeiana, but other introduced species around the world include O. septentrionalis, Xenopus spp., E. planirostris, and E. coqui. In the cases of the cane toad and the American bullfrog both species were introduced to new areas, but they adapted too well, outcompeting native frog species for habitat and food, and also eating many of the native frogs. The cane toad was introduced for pest control to sugarcane crops, yet too late it was found out they do not eat the beetle they were introduced to control. And if any other creature tried to eat the cane toad in return, it would be sickened and most likely killed by the toad’s toxins. Another down side to introducing nonnative species is the risk of diseases and fungal infections they may carry and spread the local populations.
Not all frog related negative ecological effects come from the frog’s presence either. In areas where frog populations have been wiped out, the frogs’ absence can led to populations of insects becoming unchecked. For mosquitoes, this is great but for others this means an increase in insect related diseases like malaria.
Works Cited:
Behler, J. L., & Behler, D. A. (2005). Frogs: A chorus of colors. New York, NY: Sterling Publishing Co., Inc.
Beltz, E. (2005). Frogs: inside their remarkable world. Buffalo, NY: Firefly Books Ltd.
Pepitone, J. (2008, December). Last Frog Hopping. Discover, 13.
Mongabay.com
Rhett A. Butler - San Francisco, CA.
1999-2008.
Mongabay.com
Rhett A. Butler - San Francisco, CA.
1999-2008.
(above)
Above is a photo of the Kihansi spray toad (Nectophrynoides asperginis). These toads are a prime example of conservation concern for frogs and toads, because the Kihansi spray toad lived in a specific habitat and the only known population in the wild lived within a 2 sq. mi. area. The toads were threatened by human activity on a project needed to help the human population in the area. So, efforts were made to save these toads but the wild population is believed extinct and in 2005 only a small population exists in captivity.