A species is first imported (D), then introduced (A) into the new environment.
It becomes established (B) if it adapts and thrives, and finally, it is classified as a pest (C) when it causes ecological or economic harm.
| LIST I - Ecological Parameters | LIST II - Unit of Measurement |
|---|---|
| A. Net primary productivity | I. g/m2 |
| B. Absorbed photosynthetically active radiation | II. g/L |
| C. Phosphorus | III. Joules/area/year |
| D. Plant biomass | IV. gC/area/year |