Climatic conditions prior to survey - A La Nina weather event caused widespread flooding and elevated stream heights in the months preceding the survey. Consequently, a significant amount of DNA material may have been flushed from the system, resulting in a lower rate of species detections.

Weather and river conditions during survey - Heavy rainfall and flooding also occurred during the survey period. In particular, the survey of the Mary River was affected by a significant rainfall event, which may have skewed the results for that catchment. High flows and high turbidity may have impacted the sample collection and artifically clogged filters with sediment, reduced the amount of eDNA in samples, resulting in a lower species detection rate, and therefore lower condition scores.

Seasonality - The detectability of some fauna groups (e.g. frogs) or specific species can be influenced by seasonal patterns in activity. Additional surveys during extended dry periods or periods of peak activity may result in a greater number of species being detected. Seasonal surveys could be considered for future accounts in line with the recommendation above.

Difficult to detect species - The survey targeted major rivers and tributaries. Range restricted species that were included in the reference species lists, but which occur in locations distant from the survey sites, would have a low likelihood of detection. Similarly, there may be a lower likelihood of detection of non-obligate aquatic species, including some species of frogs and birds, which are associated with aquatic habitats, but may not necessarily enter streams regularly.

Timing of the Survey - Due to flooding in May 2022, the survey was postponed until June, which is outside the seasonal timeframe recommended by the Method. While this may have influenced the results, we believe that it was preferable to sampling during very high flow conditions. For future accounts we will endeavour to sample during the in May as per the Method.