Long-term trends in functional group richness
During the investigated time period, the functional group richness (FGR)
varied between the season and area (Fig. 2). In the 1960s, the spring
time (May) FGR exhibited opposite patterns in the coastal and open sea
areas. In the coastal area, FGR was initially lower (ca. 4) and
increased during the decade, whereas in the open sea the FGR initially
decreased from ca. 7 to 5. After this time period, FGR followed similar
patterns. In the coastal area a steep increase in FGR has occurred since
the 1990s and in the open sea area FGR has increased gradually since the
1980s.
In August, FGR showed similar patterns in both coastal and open sea
areas. Initially, late summer FGR decreased until the beginning of 1990s
and was at its lowest in 1990, whereafter it increased in both areas
until the early 2000. Since the peak in the mid-2000, a decrease has
been recorded. In both areas, FGR was always higher in late summer.