[bbrock]

It's possible but not practical. Lets start with the ecological rule of 10 that says for every gram of frog, you will have to feed 10 grams of insect, which will require 100 grams of plant matter for food. Now that's just the food the frog actually eats. Obviously if you supply enough plant matter to support 10 grams of insect per gram of frog, the frog is going to eat all the insects and they will go extinct. So next you will have to turn to a set of equations known as the Lotka-Voltera equations that model populations under different scenarios. You need to use an equation that accounts for 1 predator with however many prey species you will have and, if you can design your viv correctly, you can include a refugium where predation cannot occur to reduce the population of insects needed to sustain predation. You will also need to know some information about the longevity, reproductive rates, predation rates, and non-predation mortality of the insects. Once you have all of those pieces, you should be able to calculate the size of the insect populations you would need to sustain the estimated predation. Add a little cushion for error. Then calculate the number of grams that population of insect would represent. Multiply by 10 to calculate the edible plant mass needed to support those insects. And finally figure out how large of an enclosure you need to support that plant mass. Piece of cake, right? My guess is that you would figure on something the size of a medium greenhouse to support one frog. Let us know how it turns out!

 

[bbrock]

Re: ecosystem

i actually didnt intend to have the food for the frog breeding in the tank, horned frogs eat larger pray than would be practical to keep in a viv with them. but i believe that if i included springtails, millipedes and isopods in there along with maybe some other insects to aid the breakdown of waste it may work ok, im certainly going to give it a try. i think the main problem is that if there is a pool of water what could go in there to prevent ammonia and wasdte building up in it im pretty stumped for that so far, i was thinking daphnia for starters.

Well crap! I thought for sure you were ready to slog through the math. I did think about mentioning mice as a prey item though. Anyway... two of the great differences between vivaria and aquaria are that they have aerobic soils and vigorously growing terrestrial plants. These two things combined make your basic healthy vivarium MUCH more efficient at processing nitrogen than an aquarium. Plants suck up ammonia directly so if you have plenty of root activity in the soil, plus some emmergent vegetation to help with N uptake in the pond areas, you should be fine. If you have a viv large enough to tolerate the disturbance of the frog's digging, then it will probably also have the capacity to handle the N load.

 

[bbrock]

.....how much invert prey do you think i can produce?????? It is really all about trying to maximize space with little tricks on the compost side, making it as productive as possible...i realize i will have to empty the compost side and start over every now and then but still should be a cool experiment...ben

That's a tough one to figure. Of course you could again apply the rule of ten to estimate the amount of carbon being added in the compost size and get a very crude estimate for the potential biomass of decomposers you might get out. But this estimate would include bacteria and fungi biomass as well. The other issue is how to factor in competition and predation among the soil arthropods. The compost most likely will harbor soil predators with the prey which increases the soil nutrient turnover and therefore the efficiency of the decomposition but it also might limit the populations of microarthropods available to the frogs.

It's fun to play with the math but as you already know, as you increase size, you also increase complexity and the complexity quickly grows beyond the practicality of mathematical model because of the uncertainty that grows in the system. It gets down to - try it and see what happens.

Keep us posted.

 

[bbrock]

I am also guessing that you probably are not truly composting as most gardeners consider the term, which would require enough biomass to create a sustainable heat to drive the decomposition. Keep us posted on how this works!

Garden magazines often distinguish between hot and cold composting. The end product is the same but the time it takes to complete the process is much different between the two. I once made the mistake of testing the temp of our hot composting pile by jamming my index finger into the middle. OW! and yes, it was cookin'

 

[bbrock]

It simply won't work with a horned frog unless you have huge plants, because it will cruch and uproot everything in the tank. Nothing will have a chance to grow because they won't let it, they liek to be able to see everything from their little burrow.

It's all a matter of scale. I don't think any mention has been made of the size of the enclosure needed. I think that is partly why the question was raised.