08-29-2006, 07:58 AM
I just re-read this thread and have something to share concerning the use of the chytrid fungus as a possible bio-control. I don't know where I came across this paper, this forum or a voggier one, but it says that the Chytrid fungus already exists in Coquis in Hawaii. Below is the link to the PDF of the whole monograph.
http://tinyurl.com/pscqg
The authors, Karen H. Beard and Eric M. O'Neill, conclude that the Chytrid fungus (Batrachotrytrium dendrobatidis) "should not be used as a biological control agent because it is not a species-specific pathogen, alternative hosts have not yet been identified, and it has been shown to be readily dispersed by human activities." Also, the Coquis in Hawaii already carry it with apparently no significant effect on the population.
If you google "B. dendrobatidis", or "Chytrid fungus", you'll see that it's really bad news around the world, not to be taken lightly as a bio-control.
While Hawaii has no native frog species and Cane Toads (Bufo marinus, "Poloka" in Haw) and Bullfrogs (Rana catesbeiana, "Poloka lana"
may also suffer from the use of the fungus, it's still a bad idea to go ahead and use it without doing careful studies first. Hawaii's insular biogeography is particularly susceptible to these kinds of changes.
It's interesting to find out that Cane Toads were introduced to Hawaii in 1932, from Puerto Rico, home of the Coqui! They are not native to PR but were introduced there from Mexico or South America. They are also native to South Texas. They were mistakenly thought to be an effective control of a grub that ate cane, as well as black slugs, Giant African Snails, and rats. Most of these assumptions proved wrong, but not until after they were introduced to Australia and much of the Pacific Is. from Hawaii. My herpetology field guide says that they are not a significant problem in Hawaii, as long as your dog or cat hasn't tried to eat one. But there is a video documentary about the Cane Toad in Australia that shows people in as much of an uproar about them as some people are with the Coquis here.
Bullfrogs were introduced as a possible food resource, froglegs, in the late 1800's but that didn't pan out, pun intended. I haven't been able to find out if they are a significant problem in Hawaii, as they are in CA. These were introduced from Contra Costa County, just inland from the SF Bay. Later, HI bullfrogs were re-introduced back to CA, after which they've become a problem. They are not native to the West Coast. They'll eat anything smaller than themselves.
There is one more introduced frog species from Asia, the Wrinkled Frog, Rana rugosa. This small frog is considered to be beneficial with low impact to the environment. They are found only in or around mid to low elevation mountain streams which limits them to an area from Hilo north to the Kohala Mtns. They are eaten by bullfrogs.
Another prospective food resource introduction, the Apple Snails that plague the Waipio Valley taro farmers, was hoped to provide escargot for restaurants. In their native range, these snails are almost the exclusive food resource for the endangered Snail Kite of the Florida Everglades. But, this is probably not a good reason to introduce Snail Kites to Waipio Valley as a bio-control. :-)
Sorry about going on about the extraneous stuff, but it's useful to be aware that many organisms were brought to Hawaii with not enough knowledge regarding various impacts.
Les
Edited by - Les C on 08/29/2006 12:05:41
http://tinyurl.com/pscqg
The authors, Karen H. Beard and Eric M. O'Neill, conclude that the Chytrid fungus (Batrachotrytrium dendrobatidis) "should not be used as a biological control agent because it is not a species-specific pathogen, alternative hosts have not yet been identified, and it has been shown to be readily dispersed by human activities." Also, the Coquis in Hawaii already carry it with apparently no significant effect on the population.
If you google "B. dendrobatidis", or "Chytrid fungus", you'll see that it's really bad news around the world, not to be taken lightly as a bio-control.
While Hawaii has no native frog species and Cane Toads (Bufo marinus, "Poloka" in Haw) and Bullfrogs (Rana catesbeiana, "Poloka lana"
may also suffer from the use of the fungus, it's still a bad idea to go ahead and use it without doing careful studies first. Hawaii's insular biogeography is particularly susceptible to these kinds of changes. It's interesting to find out that Cane Toads were introduced to Hawaii in 1932, from Puerto Rico, home of the Coqui! They are not native to PR but were introduced there from Mexico or South America. They are also native to South Texas. They were mistakenly thought to be an effective control of a grub that ate cane, as well as black slugs, Giant African Snails, and rats. Most of these assumptions proved wrong, but not until after they were introduced to Australia and much of the Pacific Is. from Hawaii. My herpetology field guide says that they are not a significant problem in Hawaii, as long as your dog or cat hasn't tried to eat one. But there is a video documentary about the Cane Toad in Australia that shows people in as much of an uproar about them as some people are with the Coquis here.
Bullfrogs were introduced as a possible food resource, froglegs, in the late 1800's but that didn't pan out, pun intended. I haven't been able to find out if they are a significant problem in Hawaii, as they are in CA. These were introduced from Contra Costa County, just inland from the SF Bay. Later, HI bullfrogs were re-introduced back to CA, after which they've become a problem. They are not native to the West Coast. They'll eat anything smaller than themselves.
There is one more introduced frog species from Asia, the Wrinkled Frog, Rana rugosa. This small frog is considered to be beneficial with low impact to the environment. They are found only in or around mid to low elevation mountain streams which limits them to an area from Hilo north to the Kohala Mtns. They are eaten by bullfrogs.
Another prospective food resource introduction, the Apple Snails that plague the Waipio Valley taro farmers, was hoped to provide escargot for restaurants. In their native range, these snails are almost the exclusive food resource for the endangered Snail Kite of the Florida Everglades. But, this is probably not a good reason to introduce Snail Kites to Waipio Valley as a bio-control. :-)
Sorry about going on about the extraneous stuff, but it's useful to be aware that many organisms were brought to Hawaii with not enough knowledge regarding various impacts.
Les
Edited by - Les C on 08/29/2006 12:05:41
