WP 16: Effectiveness and relative cost-efficiency of different field and laboratory protocols for macro-invertebrate samples

Objectives

To study the results of different 'invertebrate field methods', particularly in terms of errors, precision, and effectiveness in relation to the assessment/management objectives. To investigate the cost-effectiveness of different approaches to the collection and processing of macro-invertebrate samples involving varying levels of resource intensity.

Methodology/work description

This Workpackage will utilise both existing data and that obtained from a specially derived sampling programme.
In combination these source workpackages provide:

• information on the methodology applied over Europe,
• high quality, consistently identified macro-invertebrate data from sites sampled and sorted in the STAR Member States and the NAS, using standardised field and laboratory protocols for the most commonly used field techniques,
• quantification of the uncertainties associated with the most commonly used protocols for the collection of macro-invertebrate data,
• quantification of the sample processing biases of each laboratory for several protocols.

Existing data: The existing information available to this workpackage derives also from the Workpackage 3 (Review), Workpackage 4 (Acquisition of existing data), Workpackage 6 (Sampling workshops), Workpackage 7 (Investigating core stream types), Workpackage 8 (Investigating additional stream types) and Workpackage 9 (Audit of performance).

Additional sampling: In Workpackage 16, additional samples will be taken following a stepwise procedure. The sample processing will particularly address questions of sorting (what results are obtained when not all organism are sorted by hand, or only large animals are collected, or only subsamples are sorted?), identification (how many individuals must be identified to get a valid picture of the species present and how many to get a valid picture of the abundances?) and processing of counts (do we have to sample all habitats at a certain sampling surface area or can we use estimates of habitats and correct the numbers of organism from small samples to correct for the actual share of each?). The aim is, to produce a scientifically based, sound and especially cost-effective methodology for comparison with the full standard protocols.
Additional sampling will be shared between two contrasting stream types, lowland watercourses in the Netherlands and small, upland streams in the Slovak Republic.

Sampling variation and variation of results: The replicate data acquired by in the Netherlands and the Slovak Republic will be used to assess the comparative uncertainties associated with sampling and sample processing protocols of several field methods. Comparisons will be made of the following components of samples:·

• mean numbers of taxa per sample per sampling protocol
• range, standard deviation and confidence intervals of mean numbers of taxa per sample
• between- and within-method variation in the functional composition of samples
• means and variance terms for the values of commonly used metrics and other calculation methods derived from replicate samples for each field protocol.

In conjunction with data on sample processing biases (see below), these analyses will demonstrate the differences in the basic data submitted to a range of assessment protocols and how different levels of probability of assignment of sites to grades of Ecological Status may be derived from these assessment protocols.

Sample processing biases: Audit data acquired from Workpackage 9 will be used to assess the comparative biases associated with the prescriptive sample processing protocols of each of AQEM and RIVPACS. Comparisons will be made of the following components of the audit programme:

• the biases associated with each consortium Member State and NAS. Are these a function of stream type, taxonomic difficulties particular to individual ecoregions or the comparative expertise and experience of individual consortium members within laboratories?
• the biases associated with the separate processing protocols associated with each of the assessment programmes.
• the range, indicator values (if any) and community function of the taxa least successfully re-moved from samples and/or identified in each consortium Member State and NAS.

Overview