Cane toads

In general, if you record all frog species you learn:

• Biodiversity – what species of frog live on Country
• Species richness – how many different species of frog live on Country
• Presence/absence – if and where frog species live on Country
• Occupancy - If enough surveys are done at different places on Country, the presence/absence data can be used to estimate occupancy. This type of modelling helps to work how many places really have frog species, even if they weren’t seen or heard at every site.
• Activity – how many frogs are seen/heard during a survey. This can be used as an indicator of how large a population might be.

Spotlight and listen surveys are a useful tool for monitoring cane toads. Surveys involve looking for active cane toads at night with spotlights and also listening for their calls. Surveys can also involve call playback, which means playing pre-recorded cane toad calls and then listening to see if any in the environment respond by calling back. Surveys are relatively quick and easy, inexpensive, and less stressful for animals compared to other survey methods.

Spotlight & Listen Surveys are the best way to monitor cane toads, because they are active at night and their calls are distinct, and the surveys don’t need much equipment, software, or data processing like some other methods.

The best way to detect cane toads is to do this survey:

• at night
• in suitable habitat (around or near waterbodies, preferred habitats)
• peak active and calling periods (peak; December – February)
• in suitable weather conditions (warm, wet nights usually ideal)
• multiple times throughout the year

·     It is important that the cane toads are correctly identified. Use reference materials like frog ID books/apps, and take photos and recordings of all frogs during the survey so you can double check the identification. It is also useful to get people to help on a survey who have experience with identifying cane toads, particularly from their calls.

A daytime visit to your survey site(s) can help you locate the best habitat to survey, the best way to access the site at night, and if you are planning to use transects, to mark out the survey points every 50 metres with reflective flagging tape or similar.

• Biodiversity – what species live on Country
• Species richness - how many different species live on Country
• Presence/absence – if and where cane toads (and other species) live on Country
• Occupancy - If enough surveys are done at different waterbodies on Country, the presence/absence data can be used to estimate occupancy. This type of modelling helps to work how many places really have cane toads (or other species), even if they weren’t detected at every site. This can be used as an indicator of how large a population might be and if is getting smaller/bigger over time

Environmental DNA (eDNA) monitoring involves taking water, soil, air, material, plant, or animal samples which can be identified or tested for genetic traces of animals from fur, skin, urine, faeces, sperm and/or eggs in the samples. eDNA sampling is relatively easy to do, causes less stress to animals than many other survey methods, and is good at finding animals that are difficult to see, hear, or catch. By taking water samples, eDNA sampling can be used to detect if cane toads are currently living in, or have been nearby or around, the waterbody recently.

eDNA water sampling can be a good method for monitoring cane toads, particularly if you’re not sure if they are on your Country yet, or if night spotlighting and listening surveys are challenging to do. The benefit of eDNA sampling is that you can usually detect a lot of species from the same sample, but be mindful that samples can take weeks or months to process.

When planning to do an eDNA monitoring survey:

• Collect samples when cane toads are more likely to have been in or using the water body, like in the wet season or breeding season
• Sampling needs to be done when there is water in the water body so might not be possible in the dry season or drought times.
• Take multiple water samples from within the same water body, spread out across the water body. This will depend on the size of the water body (e.g. a dam vs. a small creek line) and how accessible it is.
• Be aware that water bodies and water samples might contain hazardous things, like animal faeces, bacteria, or toxic substances (animal, plant, or human), so using gloves and good hand hygiene is important.