Page 235 - Freshwater-Biology-and-Ecology-Handbook

3.1.14 CoFSI (Combined Fine Sediment Index)

CoFSIsp (Combined Fine Sediment Index species) reflects fine sediment stress. See Murphy et al. (2015) (98)
and Wilkes et al. (2017). (99)

It comprises two distinct components:
• ToFSIsp = Total Fine Sediment Index of the inorganic component of fine sediment
• OFSIsp = Organic Fine Sediment Index of the organic component of fine sediment

CoFSI – Combined Fine Sediment Index
This index reflects fine sediment stress on invertebrates. It has inorganic and organic
components and can help in identifying causes of sediment impact.

The index values are based on the position of species along Canonical Correspondence
Analysis (pCCA) axes describing gradients of total fine sediment (ToFSI) and organic matter
(OFSI). These indices are combined to form CoFSI, although they are also useful individually for
diagnosing causes of impact. ToFSI sp and OFSI sp are expressed as ASPTs.

CoFSIsp = 0.349 OFSIsp + 0.569 ToFSIsp – 6.80

It was designed from the outset to be used with RIVPACS and to be expressed as an EQI.

Freshwater Biology and Ecology Handbook | 235
–