Bird assemblages as bio-indicators of water regime management and hunting disturbance in natural wet grasslands

摘要: Abstract Responses of the waterbird community to management regime a wet grassland system (primarily small changes in water but also hunting disturbance) large floodplain lake, Grand-Lieu, were studied during three consecutive years (winter and spring 1998–2000). These temporarily flooding grasslands (1100 ha) constituted very important feeding area by supporting flocks species (52 regular spp., totalling up 14 250–22 850 birds). A global similar seasonal pattern presence was recorded whatever year. The March–May period key phase with maximum richness (42–48 spp.) abundance (30–40% total according year, essentially Anseriformes). Late Ciconiiformes lesser extent some waders exploit this area. Nevertheless bird assemblages exhibited (a decreasing level from 1998 2000, an exceptional ban January instead usual stop late February). disturbance clearly limited diurnal accessibility ducks February 1999. Also, duck population increased 55–65% 2000 when prohibited same time grew 14–19 spp. 23 2000. overall impact high on waterbirds as 1999 (with respectively 54 35 cm mean against 25 2000) increase diving fish-eating birds larger resting gulls. Conversely these conditions, notably reduced under (20 days 1998–1999 40 adverse numerous ground-feeding (Ciconiiformes waders) that require shallow waters. This study showed limitation human moderate can their attractiveness for conservation status.