For many years the students on the Comparative and Adaptive Biology field course in Mallorca have visited the strandline and salt marsh plant communities at the Albufereta Nature Reserve on the Bay of Pollença. This year, however, we went for a tour of the S’Albufera wetland (a Ramsar protected site of international importance) by Gaspar, one of the team who manages the reserve. The reserve has been protected since 1988 and is surrounded by the coastal tourist resorts and inland agricultural lands.
The land around the Bay of Alcudia is naturally marshy, with water from the seasonal rivers (torrents) held back by the sand bars at the coast. However, the marsh isn’t entirely fresh, but is brackish and salty in places as seawater infiltrates the sand to saturate the land behind. This winter was drier than average, leading to the marsh being saltier than usual for so early in the year. In the 19th century, the British civil engineer John Frederick Bateman carried out work to drain the marsh for agriculture, creating the infrastructure which is still visible today – a network of canals, ditches, bridges and old pumping houses. More recently the focus has been on retaining the water and so sluice gates have been added to maintain the wetland habitat for wildfowl. The reserve is a carefully managed mosaic of old reedbeds (dominated by Phragmites australis), open waters, scrapes and salt marsh. Horses are particularly important for managing the more open environments, keeping the reeds in check.
The human population around the reserve around 60,000, but over the summer season this can triple with the arrival of holidaymakers seeking some Mediterranean sun. This places a huge increase in demand for drinking water and wastewater treatment over the driest months in the Mediterranean. It is at these times when the reserve is at its most vulnerable from pollution (e.g. nitrates escaping from water treatment works) without the potential for a diluting influx of freshwater.
The wetland is used by some bird species all year round and by others who use it as a staging post on their migrations. With the background soundtrack provided by Cetti’s warblers, we watched black-winged stilts, avocets, egrets, a kingfisher, shelducks, crested coots and an osprey. Still, the zoological highlight happened later in the day as the flamingos treated us to a fly-by on the beach.