Fig 1.
Number of species detected during a single survey was based on: (1) autonomous sound recording (four surveys per point), (2) counting by observer, (3) corrected counting by observer (autonomous sound recording + observer counting in the same time).
Fig 2.
Influence of survey method, habitat type and experience of observer on number of detected species.
Graphs show: a) An average (per survey) number of species detected in various types of survey: counting by observer, corrected field observer (observer + autonomous sound recorder) and autonomous sound recorder; b) An average (per survey) number of species detected in different types of habitat (forest and farmland) in various types of survey. Bars represent ± standard error of mean.
Table 1.
Results of GLMM, showing the influence of factors on the number of detected species by various survey methods conducted at the same time.
Table 2.
Results of GLMM, showing the factors influence on the number of detected species by autonomous sound recorder during different surveys at the same point.
Fig 3.
The cumulative average number of species (± SE) detected per point during the different number and duration of surveys.
The average number of species detected by an observer and the cumulative number of species recorded by autonomous sound recorder are given. ASR 1/10, ASR 2/20, ASR 3/30, ASR 4/40 indicate the number of species detected by the autonomous sound recorder during different number of surveys (1–4) / different cumulative survey duration (10–40 minutes). Surveys one and two were done during the same day, while surveys three and four being completed during the second day.
Table 3.
Results of the GLMM showing how increasing the number and duration of surveys increases the number of detected species.
Table 4.
Similarity of species composition recorded by autonomous sound recorders at the same points in different surveys.
Fig 4.
Similarity of species composition recorded by autonomous sound recorders at the same points at different times.
1 –during counting by an observer vs day after in the same time; 2 –during counting by an observer vs day after but 15 minutes earlier; 3 –during counting by an observer vs 15 minutes before an observer had started counting; 4–15 minutes before an observer had started counting vs day after in the same time; 5 –next day during counting by an observer vs the same day but 15 minutes earlier; 6–15 minutes before an observer had started counting vs during counting by an observer but next day.