The Silence of the Frogs

Great Debates
1

There is a big frog pond on the farm.

Over the last several years it has become clear that the frogs are going away.

  1. no fertilizers or pesticides near the pond

  2. ph is stable and neutral

  3. no algae blooms

  4. no pollution
    There is a big debate as to what is causing the world frog decline. Environmentalists blame the environment. (I’m not buying, the environment of my pond is fine) Scientists have lots of ideas, but no leading theory (that I’ve heard), and creationists claim that God has decided not to do the plague of frogs thing again so there is no sense in keeping the ugly bastards around any more. :slight_smile:

Anybody want to hash it out?

Toads, (the kind that are spontaneously generated from heavy rains) seem to be doing fine. (at my house anyway) Why are they excused from this disaster?

BTW, I remember hearing about giant cannibalistic African frogs so nasty they’ve wiped everything out but themselves and algae in their environment. The tadpoles eat the algae The frogs eat the tadpoles, each other, and anything else that happens to walk by. Also remember that these frogs have some kind of super adrenaline kind of thing going on that enables them to shift from their usual slothlike lethargy into high-powered frenzies of attack for brief periods. Can’t find anything on them though.

Was it just a bad dream of mine, or do they exist?

Maybe I should have put this in GQ, but I figure a debate could grow here quickly, and I’m getting sick of what-if? religious debate.

Can we give it a shot?

2

Clearly, there are too many French restaurants. Next thing you know, snails will be an endangered species, as well.

3

I do like frog legs, but we never took many, and have desisted for the last few years becuase of the low population.

I also understand this is a global problem not confined to culinary frogs.

4

Your killer African frogs memory is from Legacy of Heorot by Niven and Barnes (and maybe someone else, I cannot remember).

The frog really only eats its own tadpoles, because it cannot eat the algae in the stagnant pools in which it lives. I wish I could remember the species…

The “super adrenaline” was invented by the science-fiction writers to make their grendels extra nasty.

5

DrF:

Yes, that sounds right. I do read their stuff. I remember the Grendels now. Science and science-fiction seem to be mixing freely in my head. Thanks.

6

I don’t think there’s enough information to pin down the cause, but here are a few hypotheses I’d like to toss out there:

  1. Rise in parasites (this has been found in some cases of amphibian decline)

  2. Rise in competitors for food or territory, or rise in predation

  3. Decline in food source (what kind of frogs and what are they eating?)

  4. Decline in immigration from source population (especially if your local frog population is actually a metapopulation)

  5. Habitat destruction… not limited to destruction of the pond, could be destruction of areas near the pond used for breeding or feeding, or of the rendering of these habitats useless for the frogs (like if the frogs need to call to mate, but the noise of a nearby freeway drowns out the sound of their calls on their breeding grounds, the population is likely to decline)

  6. The time is upon us. All frogs report to sector 7-G for instructions on their part in the overthrow of Homo sapiens, pretender to the planetary throne.

That’s all for now, but given time I could probably come up with some more.
-Steve

“Heyyyy sexy mama! Wanna kill all humans?” -Bender, Futurama

“Your game shows reward knowledge. Ours punish ignorance!” -The Simpsons

7

Wevets:

Thanks for the reply.

  1. There’s nothing in the pond besides frogs, bass, sunfish, the occasional snapping turtle, and maybe a snake or two. Any idea how to check a frog for parasites? How would they have gotten there, or spread across the whole world to suddenly decimate the frog population? WHy don’t they affect toads?

  2. No new predators. Bass population is pretty stable, not an especially high number of snakes or anything.

  3. Your basic Pennsylvania garden variety bass-pond frog, I guess. Insect eaters, I guess (plenty of bugs here)

  4. It’s a spring-fed man made pond about 1 1/2 acres. One outlet, perpendicular drainpipe that drains the water when it reaches a certain level. I don’t know where the frogs come from, but would guess it’s a large enough pond to be self-sustaining.

  5. No new construction, pretty far from major roads, farm country.

  6. maybe

Using my pond as an example. Mostly interested in worldwide decline rather than my specifics.

8

Scylla wrote:

There was a real-life species of African “clawed frogs” that made it to America. This was in the news well over a decade ago. While not cannibalistic or posessed of super-adrenaline attack frenzies, they DID eat other, smaller frog species. Plus, they tasted really bad to local crocodiles and alligators, so they didn’t get eaten very often.

9

I remember when I was a kid, back in the 70’s, going to my grandparents house in Temple, Tx. Me and my cousins would look for Horny toads (frogs) in their back yard, and always find at least one. By the 80’s none could be found.

10

I remember when I was a kid, back in the 70’s, going to my grandparents house in Temple, Tx. Me and my cousins would look for Horny toads (frogs) in their back yard, and always find at least one. By the 80’s none could be found.

11

I used to collect a pint jar of tadpoles from a swampy area near here, raise them in a fish tank and set them free as they got legggggs.

Haven’t found any for 5-7 years.

I thought it had something to do with the ozone layer.

The toads that live at my front and back doors are still here and the tree toads/frogs are as loud as ever. (Or will be in a couple of months.)

Just seems to be the frogs.

Are you driving with your eyes open or are you using The Force? - A. Foley

12

I had heard of the frog decline also, and found a number of web sites with information, but as you said, they almost all blame environmental factors. Here is a least one other explanation given, from:
http://www.tigerherbs.com/eclectica/earthcrash/subject/deformities.html

13

Just a small point of clarification, cooldude. Horned toads are lizards, not frogs. The generally accepted theory of their demise is the invasion of the fire ant. Although horned toads eat ants, they were used to the more tranquil domestic variety. They weren’t prepared when ants started counterattacking.

Now, back to the amphibian discussion.

14

Gilligan, the fungus cause is just as untouchable as the “ultraviolet radiation penetrating the atmosphere due to the thinned ozone layer” cause. We can no more medicate all the waters than we can put umbrellas over all the frogs. Doesn’t look good.

Are you driving with your eyes open or are you using The Force? - A. Foley

15

Oh, OK. It just seemed from the way you discussed your local conditions in the OP that you were specifically curious about what might be happening close to home.

My guess would be that there are many factors contributing to the worldwide decline of amphibians. As as been mentioned in the previous posts, potential causes for the amphibian declines have been seen as:

  1. Habitat destruction & fragmentation
  2. Parasites
  3. Diseases
  4. Pollution
  5. Increased exposure to UV
  6. Climate change
  7. Spread of invasive/exotic species
  8. Increased predation
    … there may be more, but I don’t have the time right now to generate an extensive list. Actually, a better list is available at: Darn they made a better list than I did!

There is good enough evidence for several of these factors (especially 1, 2, 3, 4, and 7), IMHO, to suggest that different factors are operating in the decline of different populations of amphibians, and that in some populations, multiple factors are the cause.

This is what’s caused a bit of confusion in my mind for a couple reasons:
[ul][li]I can’t think of any example of the decline or extinction of a species that has nothing to do with the environment that species lives in. It follows that if the frogs in your pond are disappearing, something in their environment is the cause. Perhaps you meant that you don’t believe anthropogenic changes in the environment are the cause?[/li]
[li]If we’re talking about the worldwide decline of amphibians, your pond could still be fine, and it would not preclude the possibility that in the rest of the world, ponds aren’t doing so well, causing amphibian decline.[/ul][/li]
But it is still possible that all the environmental factors in your pond are suitable for frog habitation, and that the frogs in your pond would still be in decline.

An excellent example of research into why frogs did not inhabit ponds thought to be well-suited for frog habitation can be found in Gulve, P.S. 1994. Distribution and extinction patterns within a northern metapopulation of the pool frog, Rana lessonae. Ecology vol. 75(5): 1357-1367. A short summary is this: Gulve was curious as to why physical characteristics of ponds did not predict as well as expected frog habitation or extinction. He found that while warmer summer temperature tended to be correlated with occupied ponds, a more important variable was the presence or absence of frogs in nearby ponds. Frog populations were sustained by large source populations, and the farther the pond was from a successful source population (and successful source populations in his area were being eliminated by succession and by farmers draining ponds), the less chance that the pond would be occupied by frogs. I suspect many of the ponds he discusses are larger than your local pond, because he describes some of them as “lakes,” however, he does not state the size of these ponds. This mechanism may also be causing the decline in your local population.

AFAIK, toads, part of the Order Anura along with frogs, are also being effected by the worldwide decline in amphibians. I don’t know why they aren’t declining in your pond at the same time the frogs are, but there’s no reason that any of these hypotheses would have to have the same impact on both groups.

Unless, of course, the creationists are right, and God’s not planning on another plague of frogs, but He does want to keep the toads around just in case we start using His people to build some more pyramids! :wink:
-Steve

16

Recently here in Minnesota, they discovered a large increase in the number of deformed frogs (too many legs, missing eyes, etc.) A newspaper article plotted the locations of the malformed frogs and noted that, in the middle of the largest area of frogensteins, there was a petroleum processing plant. Also nearby the plant was a protected nesting area for herons. They hypothesized that the herons waded in the funky water and then transported the nasties to the other ponds in the area.

Certainly not incontrovertible, but worth further study.

17

So other than the disappearance of several entire species the environment is doing okay?

18

It appears to me that when the decline was first noticed, there was an assumption within a segment of the scientific community that man was somehow at fault. There was then a great rush to blame the decline on everything from fertilizer runoff to depleted ozone. It now appears that parasites may be the cause of the decline. (I am sure there are now some folks hard at work to blame the parasites on humanity.)

I think we need to be cautious about approaching science with a political agenda. That approach tends to create blind spots. Obviously, in many cases “man is at fault” is a pretty good hypothesis. We need to be careful about confusing ‘hypothesis’ with ‘proof,’ and we need to be careful.

Don’t get me wrong. I’m against all that evil pollution, too. Just don’t hit me with a bunch of pseudo-science to justify the need to reduce pollution levels.

19

We need to be careful about proof reading our posts, too. :o

20

Wevel:

Thank you for the excellent reply.

(Note to self: DO not get on the opposite side of a scientific discussion with Wevel)

Obviously anything that happens to a frog happens in it’s environment. I should have clarified that I meant environmentalist concerns such as pollution, acid rain, Dumping, noise, construction, fertilizer, etcetera.

If a purely natural disease wipes out all the frogs then obviously that occured within their environment. But it’s not what I meant. Sorry for the confusion.

I use my pond s an example. Kind of a control group that has had no discernable environmental pressure place on it, yet is suffering a severe and sudden frog decline.

Parasites, seem most likely to me now.
Little Nemo:

What species are you referring to? How does their disappearance prove the environment isn’t ok.

As I’ve mentioned, my pond is only an example of a fairly pristine environment without any pressures from man, or any obvious changes, that is nonetheless losing frogs.

The fish, dragonflies, snakes, turtles and fowl which inhabit the pond seem to be doing very well.

You said: