Hi Tad (and for everyone else, this will be a long response so I will make a second post after this one).
snip "I meant to say the math is accurate just didn't think you conclusion was/is logical... but I guess in all honesty I'm not entirely sure what you are trying to say. At one point you seem to be stating that the only important factor in tank size as far as the frog is concerned is floor space. Then you go on to say that the rest of the space can be used to house other species? As if this space will be ignored by dendrobates and used by ?xxx species?"
I am building up to a couple of concepts that are very counterintuitive and I guess I am taking the long road to them. The simplistic set-up is to get people thinking about all of the unused space in some of the tanks, that may or may not be utilizable by the dendrobates. There is a lot of volume in the tank that can be utilized by other species. I think I make this clearer in the next installment.
Snip "Honestly I don't think anyone has ever meant 5 gallons per frog to be a hard and fast absolute. Obviously common sense comes into play. But considering the typical landscaping and layout of most tanks, I would think its a decent figure. I do think that both a 20 high and a 20 long can house the same number of frogs. When all is said and done if they're landscaped/stocked with plants properly you end up with a fairly similiar amount of useable living space. I think this would hold true up to your larger size tanks (120-280). Though this will depend on how dense the vegitation happens to be."
This is not what I have had said to me in some recent pms. There is a strong belief in the 5 gallons/frog as an absolute minimum and I think that when people are considering multispecies enclosures this can be a problem (heck I think as an absolute its a problem anyway). Its a good starting point but for planning but its taken (in my opinion) way too seriously. I have more to say on this in the next installment.
in the larger enclosures the minimal amount of floor space decreases but the total amount of space increases. It is this other space that needs to be considered for other species."
snip "I'm thinking you mean the ratio of floorspace to volume decreases and that the frogs are primarily concerned with floor space? And that much of the newly available volume is inaccessible to the frogs (being that its space near the ceiling? or in the emptiness between the top and bottom?)."
(The main point to remember I am only discussing the minimal amount (and only the minimal) per frog available). Not that they are primarily concerned with floor space (even though my experience with a lot of tincts had this to be the most common pattern) but in a simple set-up you are pretty much restricting the frogs to the floor space (by limiting the available cover and habitat). But again it was partly to get people to consider that a simplistic set-up does not give the frogs as much space as you might believe.
Snip "I think the "wasted" empty space between the top and bottom can be used if the tank is planted in a lush manner (think about the difference between a gymnasium and a 3 story apartment building that share the same dimension."
This is where I am slowly going. I make some assumptions on this in the next post that increase the amount of space in the calculations. However, this still does not provide a 100% usage of the space.
snip "But that doesn't seem to be typical or even atypical but maybe limited to something a frog would travel in and most certainly not a display tank."
I have bred tincts, auratus, azureus, E. tricolor and P. terriblis in those types of set-ups. They are the sort of setups you see in areas that are looking to breed frogs and need to be able to individually account for the frogs on a daily basis (Cincinnati's entire off exhibit breeding set-up was kept this way). This may not be the most common in many private hands but it is not that uncommon either.
snip "But once again I'm not entirely sure what your getting at, if the volume/space of the tank is not accessible to by the frog I don't see it being used by species "X" either. Unless were talking about humming birds? or some other flying/hovering species. I have what I would consider to be somewhat moderatlely planted 29 gallon tank with 3 tincs and I would say the tincs spend more than half of their time *not* on the ground."
There are other options than hummingbirds (whose density is limited not by space but the number and location of nectuaries but are still one mean bird).
Snip "I think you could talk about different "zones" of the tank being utilized by different species if your talking about tanks that are more than 6ft high. I would assume that any dendrobate would be willing and able to use/climb the vertical space of any tank that was shorter than 4ft."
Doesn't have to be that big depending on the choices. But then I am talking about more than dendrobates here.