Niels Martin Schmidt Impacts of wet grassland management and winter severity on wader breeding numbers in Eastern Denmark

Wader population development Most wader populations are declining in Denmark, and in Europe in general From Jacobsen (2000)

Wader population conservation Large efforts are being invested in reversing this trend => mainly focused on wet grassland management Waders also respond strongly to winter severity Relative importance of grassland management and winter severity

The Klydesø reserve Area of national interest as wader breeding ground Lapwing Redshank Avocet Ringed plover Oystercatcher Reclaimed from sea in 1945 => Situated below sea-level => Large succesional changes => Detoriation of costal meadow as wader breeding ground

Population development in the Klydesø reserve Grazing Winter flooding

Management implements Cattle grazing (app. one steer per ha, ha) Winter flooding (app. 115 ha shallow water) Expected effects = more breeding and foraging habitats Fox exclusion Expected effect = less predation on nests

Winter severity Proxy of winter severity: NAO winter state Expected effects of mild winters (high NAO) Improved survival when migrating and when on winter grounds Early onset of breeding in years following mild winters Changes in food availability on tidal flats

Population models Autoregressive analyses Most parsimonoius model selected by AIC c N t = N t-1 N t-2 GRAZING WINTER-FLOODING NAO

Waders, management and climate N t-1 N t-2 NAO t GR t-1 WF t R2R2 Lapwing Redshank Avocet Ringed plover Oystercatcher

Lapwings and winter severity N t-1 N t-2 NAO t GR t-1 WF t R2R2 Lapwing (Klydesø) Lapwing (Tipperne)

Conclusions Management implements did result in increased (most) wader breeding pairs Multi-lateral conservation approach needed for ensure coastal meadow species diversity Winter severity may be more important when management effort is constant

The Lapwing paradox High predation pressure on nests (c. 90%) => too low production of young to maintain population size Where do the lapwings come from?

The Lapwing paradox Underestimation of production of young? Attract birds from other (declining) population? Production of young in arable areas, e.g. cereals?