Effects of water level and grassland management on alpha and beta diversity of wet grassland birds in restored wetlands

Nearly 60% of European wetlands have been lost to drainage or to the cessation of grassland management. Large amounts of resources are put into wetland restoration with the aim to recover biodiversity. However, few studies have simultaneously evaluated effects of management, wetness and flooding dynamics on biodiversity of restored wetlands such as seasonally flooded wet grasslands. We inventoried bird communities over 4 years at 137 sites (each 3·1 ha) within five restored wet grassland areas in Sweden to investigate whether species richness and occurrence of 12 common wet grassland species were related to (i) local conditions such as management (grazing, mowing and unmanaged areas), basic wetness and spring flooding dynamics. Further, we investigated whether (ii) the composition of the adjacent landscape (20 ha) related to local bird diversity and (iii) species turnover (i.e. beta diversity) differed between sites characterized by their basic wetness, degree of flooding and predominan...欧洲近60%的湿地因排水工程或草地管理措施终止而丧失。为恢复生物多样性，大量资源被投入湿地修复工作中。然而，鲜有研究同时评估管理措施、湿度状况与水文波动对季节性淹水湿草甸（seasonally flooded wet grasslands）等修复湿地的生物多样性的影响。本研究在瑞典5处修复湿草地区域内的137个样地（单个样地面积3.1公顷）开展了为期4年的鸟类群落调查，旨在探究以下三方面内容：(i) 物种丰富度与12种常见湿草甸鸟类的出现率是否与局部环境条件相关，包括管理方式（放牧、刈割与未管理区域）、基础湿度以及春季水文波动；(ii) 周边20公顷范围的景观组成是否与本地鸟类多样性相关；以及(iii) 以基础湿度、淹水程度及主要（原文未完整表述）为特征的样地间，物种周转（即β多样性（beta diversity））是否存在差异。