BIODROUGHT index calculator

This BIODROUGHT calculator allows calculation of the BIODROUGHT multimeric index, which determines the probability that a drying event occurred in the year preceding sampling). The calculation is based on analysis of the taxonomic and functional composition of macroinvertebrate samples taken < 1 year after the suspected flow resumption.

The calculator analyses single samples comprising a list of taxa and their abundances. Either import your data as a CSV (comma delimited) file or manually enter each taxon and its abundance.

If importing a .csv file, enter “taxa names” in cell 1A and “abundances” in cell 1B, with data in cells 2A and 2B onwards. During the calculation, any additional information (e.g. species traits) will be added to your taxa list and any necessary taxonomic adjustments will be made automatically. The taxa in your data file must be included in the calculator database, which you can download HERE. If an entered taxon is not in the database, a warning indicating mismatched names and suggested alternative taxa names is printed.

Ensure the correct season is selected, because the calculator uses different formulas to calculate the index for spring and autumn seasons; the calculator is not suitable for samples collected in other seasons .

The calculator will produce the following output. Further information on each metric can be found HERE:

Sum of indicator taxa weights
Czech saprobic index
Number of individuals
BIODROUGHT score
Probability of classification as intermittent stream (Typically complete streambed drying for > 7 days in a stretch > 1 km)
Probability of classification as stream vulnerable to drying (Typically partial streambed drying for < 7 days with persistence of residual pools , in a stretch < 1 km)
Probability of classification as permanent stream (continuous surface flow prior to sampling)

BIODROUGHT multimetric index limitations:

	VALID	LIMITED VALIDITY	NOT VALID
Biological sample characteristics
Czech saprobic index	≤2.3	2.3 - 2.7	>2.7
Sum of indicator taxa weights	≥12	12 - 10	<10
Number of individuals	>300	100 - 300	<100
Acidity class (Braukmann & Biss 2004)		4 - 5
Stream characteristics
Strahler order	1 - 4	5 - 6	>6
Altitude (m a.s.l.)	200 - 500	500 - 800	>800
Ecological status	high to moderate	poor	bad
Water body alteration			artificial, heavily modified
pH	>6.5	6.5 - 5.5	<5.5
BOD 5,(mg*l-1)			>3.8
N-NO3- (mg*l-1)			>5.4

Notice: This method was calibrated for aquatic macroinvertebrate samples collected in the Czech Republic using a proportional multi-habitat 3-minute kick sampling method (Czech PERLA method, Kokeš et al. 2006 ) in either spring or autumn. BIODROUGHT score thresholds are set differently for each season (see specifications for autumn and spring sampling dates). Taxa in the training data set were identified to species (70% ), genus (20%) or a higher level (10%); different taxonomic resolutions may affect the validity of calculated results.