Considerations for Frog Ponds in the Tropics
As more and more people move to Far North Queensland, there is increasing pressure to remove habitat and replace it with houses. This is still one of the leading causes for frog decline in this region. It does help frogs if microhabitats can be provided for them so that they can still have places to live and breed whilst having to share that space with humans. This page covers the basics of setting up a frog pond in our tropical climate.
If you are outside Australia, please be aware that the suggested techniques and references to keeping toads out of ponds only pertains to areas where the introduced cane toad (Bufo marinus) is a pest. Australia has no naturally occuring toads so any and all attempts to exclude toads are against the cane toad. If you live in the US or Europe or Asia, you don't want to exclude your own local toad species from your ponds. In fact, many species of toads are endangered and these are species you would want to help - not exclude!
The Pond Itself
A new threat to frogs: fluoridated water!
If you live in the tropics, you are required by law to keep fish in your water bodies to control mosquitos. Small species of fish with small mouths (e.g., basic guppies, Pacific Blue-eyes, white clouds) are the way to do this when you want frogs to breed in your pond. However, since the Queensland state government mandated that fluoride is to be added to the water supply (this started locally in December 2010), we have seen three major changes to small fish species:
This situation with fluoride affecting small fish is a major problem for frog ponds and becomes yet another cause of frog decline by preventing recruitment. Even if your pond is entirely rainwater and never topped up with the hose, the fish could have been bred by or resold by aquariums that are using fluoridated water. Because the fish don't stay very long at a seller's facility, the mortality rate might not be noticed or reported back to the seller. The customer (you) buys the fish and they die soon after without breeding, but you may not bother complaining to the shop, thinking that it was your fault the fish died. (This has been a recurring theme with many small animals that are in the trade.)
To provide "safe" fish for your frog pond, you will need to ask aquariums about their water supply and the water supply of their suppliers. The fish will need to come only from suppliers with their own reverse osmosis setups and you will need to avoid using tap water to fill your pond. Rainwater, pure water brands from the shops, and your own reverse osmosis water filter (domestic filters should run about $400-$500) are acceptable for your frog pond. (You can also write to the authority in your area who requires fluoridation to complain - this policy is bad for your health as well as being bad for frogs.)
Update: QLD government turned tail on the fluoridation law and has now left it up to individual councils to fluoridate or not. Thankfully for this region, Cairns, Cassowary Coast, Douglas and Tablelands councils have all voted against fluoridation. There are now ten councils in QLD (as of this writing that have abandoned this controversial practice but sadly that is not the situation in southern states or overseas.
Frog ponds are supposed to be for frogs but if you have one, the toads will happily use it. There are three ways to keep toads out of the pond: one is to make it an above-ground pond at least 60cm high with vertical walls (but some frogs don't favour these setups), and another is to put the pond in-ground but exclusion-fence off around the pond or yard and remove the toads still inside. The disadvantage of the above-ground pond is that it will be used by the tree frogs only so the ground dwelling frogs miss out. The third (cheaper) way is not to barricade the toads out but to remove the toads and their eggs regularly.
If you want to provide a physical barrier to toads with a dug-in pond, you merely need to provide a solid barrier which extends several inches down into the soil and reaches about 60cm above the ground. For example, a chain link or tubular pipe fence can have shade cloth attached and low shrubs or heliconias can be planted to hide the shadecloth. More information on this is in our Toad Exclusion page. If neither an above-ground pond nor a fence is possible, then a regular vigilence on the pond to remove toad eggs is the next best option. (See our pages on Toad Eggs and Humane Disposal)
Around the pond
Water quality issues
Frog ponds are one of the best ways to help restore frog populations so we hope you'll want to put one on your property soon! Please contact us if you have any questions that haven't been covered in this page.