Recording absence records on the FrogID app

The FrogID app now includes the ability to let us know when no frogs are calling - an ‘absence’ or ‘null’ record, adding scientific value to the FrogID dataset.

The Australian Museum’s FrogID citizen science project uses smartphone technology to record frog calls to better understand and conserve Australia’s unique frog species.

FrogID contains two main sources of data. The first is the audio files themselves, which is used to identify the species calling and can also be analysed in detail to help understand frog accents, discover new species to science, and determine how frog communication is changing with urbanisation (including other things). The second is occurrence records – records of the locations and dates where frog species were recorded. This data can be used in all sorts of research including species distribution models, understanding impact of fires, drought, floods, or disease.

Until now, FrogID occurrence data has been gathering presence-only data, revealing a species being present and calling at a time and place, but not when species are absent. Instead, we have been able to infer species absences by creating ‘pseudo-absences’ – when FrogID recordings with one or more species calling but other species aren’t calling, we can assume a pseudo-absence for those species.

While various statistical and modelling techniques are being improved to strengthen analysis of presence-only data, true absences really increase our ability to understand where frogs are (and aren’t) and how they are doing.

For this reason, we have now included the ability to let us know when no frogs are calling - an ‘absence’ or ‘null’ record.

To ensure your absence records add value to the FrogID dataset, please remember:

• Only select the Null Record option when you are certain that there are no frogs are calling (remember that some insects sound like frogs and vice versa!). If you’re unsure, please leave it unselected - we will still listen to the recording and let you know!
• Only select the Null Record option at a site where you have heard frogs before, or you suspect they are there at other times (ie. ponds, dams, wetlands, creeks) and not away from potentially suitable frog habitat (ie. in an office tower or on the beach).
• Only submit one null record per night per site (~100m). Watch a video on how to submit null records on the FrogID app here.

Thank you for strengthening the FrogID dataset through your presence and absence recordings. While recordings of frogs calling are the most important submissions you can make, recording the absences of calling frogs is also incredibly valuable. Together, we are building an incredibly powerful resource that can be used across a wide variety of research contexts that will help better understand and conserve Australia’s unique frog species.

Dr Jodi Rowley, Curator of Amphibian & Reptile Conservation Biology at the Australian Museum and UNSW.

Nadiah Roslan, FrogID Project Coordinator at the Australian Museum.