Different types of environments resulting from the dynamic equilibrium between the sea, the river and freshwater can be found in the Baix Ter plain. The interaction between the sea, the river and the sediments it carries has given rise to a wide variety of ecosystems, with very subtle variations in the duration of floods, depth, salinity, nutrient content or type of substrate. The variety of environments and the diversity of organisms that can be found in them are two of the most important ecological aspects of the area. A description of the main aquatic ecosystems found in the Baix Ter follow.



- marshlands and coastal lagoons.

They are situated in the depression just behind the sand dunes, an area easily flooded in stormy weather due to its low level and flat surface. Storms can be followed by rain and floods, so water flooding the marshes is a mixture, in variable proportions, of freshwater and seawater. The ground is clayey, little permeable and retains the salt and water with the consequence that marshland vegetation, mainly glasswort and reed beds, is adapted to high salinity levels and periodical flooding.

Vegetation profile of La Pletera

In lower areas were water is present permanently or nearly permanent, coastal lagoons with brackish waters, due to seawater penetration, can be found. These seawater influxes are sudden and short in time. Evaporation, water drainage and the lack of further water influx results in an increase in salinity levels; sometimes reaching higher levels than those found in seawater. La Pletera is the most extensive marshland found in the Lower Ter, with Frare Ramón’s’ being the most characteristic brackish coastal lagoon.

- coastal freshwater ponds
- springs
- inland temporary ponds
- river Ter estuary
- strongly humanized aquatic atmospheres