Although grazing on seagrasses is generally considered to be minor in many temperate regions of the world, waterfowl are often considered significant grazers in temperate lagoons and estuaries. This study examined grazing interactions between the black swan (Cygnus atratus) and the seagrass Halophila ovalis in, the Lower Swan River estuary, Western Australia.
The study has:
Characterised the spatial and temporal variation in black swan abundance at 45 sites across four seasons (spring, summer, autumn and winter) and at different times of day investigated the changes in grazing pressure exerted by swans over a year; and experimentally examined the strategies seagrasses use to cope with grazing.
Some key findings:
Plant-grazer interactions are dynamic and complex. This study is revealing that the expression of traits that afford tolerance to grazing varies across a year. It is also showing that changes in the plants’ sexual reproduction may be strategy to cope with grazing.
Please leave a comment about your rating so we can better understand how we might improve the page.