Table 1.
Distribution classes describing relative rarity and commonness of benthic macroinvertebrates in the Netherlands [26].
Fig 1.
Frequency distribution of taxa among hierarchical levels in this dataset.
Table 2.
Datasets compiled and used in this analysis.
Fig 2.
Logarithmic scatterplot illustrating that most taxa in this dataset are infrequently observed.
Fig 3.
Taxon-specific relative percent difference (RPD) plotted against frequency of observation (FREQ), or percent of total number of samples.
Fig 4.
Uncertainty/frequency model categories delineated relative to the graphic pattern shown in Fig 3.
Fig 5.
Distribution of taxa within uncertainty/frequency categories (UFC1-6).
Uncertainty is expressed as relative percent difference (RPD) and relative rarity or commonness as frequency of observation (FREQ). Each point represents a taxon.
Fig 6.
Proportion of taxa falling within six uncertainty/frequency classes (UFC).
Approximately 67% of taxa are reliably identified with a high level of certainty (UFC 1–3), and 24.1% (UFC 5) are identified with a low level of certainty. Taxa within UFC 3 and 5 are also considered as rare or having a low frequency of observation.
Fig 7.
Percentages of taxa in “major” benthic macroinvertebrate groups in six uncertainty/frequency classes.
1, high confidence, common; 2, high confidence, moderately common; 3, high confidence, rare; 4, moderate confidence, rare; 5, low confidence, rare; 6, outliers, mixed.
Fig 8.
Percentile distributions (boxplots) for frequency of taxon occurrence (FREQ) and relative percent difference (RPD) among the uncertainty-frequency classes.
FREQ is the percentage of samples for which a taxon was observed; RPD is a measure of uncertainty associated with taxonomic identifications, thus lower values equate to increased confidence. 1, high confidence, common; 2, high confidence, moderately common; 3, high confidence, rare; 4, moderate confidence, rare; 5, low confidence, rare; 6, outliers, mixed.
Table 3.
Identification uncertainty/frequency Classes (UFC).
Table 4.
Descriptive statistics for relative percent difference (RPD) and frequency of occurrence (FREQ).
Table 5.
Selected taxa as representative examples of uncertainty/frequency classes (UFC).
Table 6.
Numbers of taxa by uncertainty/frequency class (UFC).
Table 7.
Relating relative percent difference (RPD) to distribution classes.