Restoring hydro-impacted wetlands for secretive marsh birds

Secretive marsh birds can be difficult to detect and are dependent on wetlands, leaving them vulnerable to wetland loss or alteration. This study examines the influence of management-altered hydrological regimes on five secretive marsh bird species in the West Kootenay and Columbia Wetlands in British Columbia, Canada. Focal species occupied wetlands with less frequently altered hydrological regimes more often and in greater numbers. Occupancy models suggested that woody vegetation, tall vegetation, and open water are important drivers of occupancy for these species. Wetlands most frequently experiencing heavily altered hydrological regimes had more open water and less tall vegetation, both of which were negatively associated with wetland occupancy. Water management operations may be promoting altered vegetation communities within these wetlands, in turn promoting lower occupancy of secretive marsh bird species. Restoration recommendations include: prioritizing lower elevation wetlands, limiting woody vegetation encroachment, and experimentally restoring the hydrological regime of affected wetlands.