Wetland Seed Availability for Waterfowl in Annual and Perennial Emergent Plant Communities of the Rainwater Basin

The Rainwater Basin (RWB) provides critical habitat for many species of migrating waterfowl during spring migration. Conservation planners are currently using a bioenergetic approach to evaluate waterfowl habitat needs for this region, yet forage availability is currently unknown. We evaluated wetland-derived seed availability on publically-managed wetlands to determine mass available in emergent plant communities dominated by annual moist-soil species (MSA) and perennial moist-soil (MSP) stands. Prior to spring migration, 10-cm deep core samples were collected from 12 wetlands (n = 97) in 2010 and 13 wetlands in 2011 (n = 107) across 5 counties throughout the RWB. Available seed biomass for all areas sampled was 685.7 ± 45.9 kg/ha). Between these two common plant communities, mean seed mass was significantly greater (Z = 4.78, P < 0.0001) in MSA stands (x¯$$ \overline{x} $$ = 907.2 ± 84.6 kg/ha) than in MSP stands (x¯$$ \overline{x} $$ = 488.7 ± 33.5 kg/ha). Carrying capacity estimates can now be estimated for publically-managed RWB wetland habitats by determining if stands are dominated by annual or perennial species. In addition, land managers can now determine if management treatments will maximize seed biomass for spring migrants based on stand composition during the growing season.