Table 1.

Description of the six clusters and their concomitances.

Vegetation cluster	Main concomitant vegetation
Potamogeton malaianus cluster	Vallisneria natanus, Ceratophyllum denersum, Hydrilla verticillata
Nymphoides peltatum cluster	Potamogeton malaianus, Trapa incise, Vallisneria natanus
Nymphoides peltatum-Potamogeton malaianus cluster	Trapa incise, Ceratophyllum demersum, Vallisneria natanus
Vallisneria natanus cluster	Ceratophyllum demersum, Elodea nuttalli, Hydrilla verticillata
Vallisneria natanus-Elodea nuttalli cluster	Nymphoides peltatum and Ceratophyllum demersum
Najas marina cluster	Potamogeton malaianus, Vallisneria natanus