Table 2. Justification and equations for introduction, maintenance and domestic risk (all RFs have previously been multiplied by the presence-absence matrix)

RFs used and equation Transformation Justification

Introduction Risk (IR)

RF1*RF2

For each count, for each species (no value for may 2007 due to RF1 calculus)


None

Each bird entering the community is associated with a AIV risk related

Maintenance Risk (MR)

RF3+RF4+RF5+RF6+RF7

For each count, for each species


Standardized

Each RF is additive to the others
Domestic Risk (DR)
RF1+RF2+RF3+RF4+RF5+RF6+RF7

For each species observed simultaneously in waterfowl and domestic compartment


Standardized

Each RF is additive to the other and RF1 & 2 represent also a risk of introduction for the domestic compartment