Macrophyte habitat selection by moulting mute swans and the effect of recreational disturbance in the largest Baltic Sea lagoon

By Rasa Morkūnė, Martynas Bučas and Julius Morkūnas

Recreational activities and shipping lanes often occur in close proximity to molting areas of waterfowl but knowledge on this disturbance effect is scant. In the Curonian Lagoon, situated in the south-eastern Baltic Sea, we combined visual observations, satellite telemetry and the distribution of macrophytes to study habitat use by moulting herbivorous mute swans (Cygnus olor).

Mute swan with a neck collar containing a solar powered GPS-GSM transmitter

Our data showed the most important swan staging areas are shallow areas (<1-metre depth) with diverse and high-density coverage of submerged vegetation dominated by charophytes and pondweeds. The submerged macrophyte habitats in water depths of 1–2 m and stands of clasping-leaf pondweeds were considered less important for swans. In the study site, mute swans exploited only half the most suitable habitat areas for feeding. Based on indirect assessment of the relationship between the abundance of swans and disturbance by kitesurfing and boating, we discuss possible impacts on their moulting grounds.

The full article can be found here