Vegetation, livestock and waterfowl responses to hydrologic gradients in created wetlands of the dry mixed grass prairie

Declining Pintail (Anas acuta) populations in Canada's Prairies have been linked with crop agriculture, drought, and associated habitat loss. Although created wetlands may enhance breeding and nesting opportunities, artificial flooding may change desirable spikerush (Eleocharis palustris ) communities to undesirable monotypic stands of cattail ( Typha latifolia). Using greenhouse and field studies, this research examined the likelihood of using various flooding regimes to control cattail in affected wetlands, as well as enhance and/or restore spikerush in new and established wetlands.;An initial greenhouse study indicated that unlike spikerush, cattail was highly tolerant of moisture stress, with soil moisture below 5% required to induce rhizome mortality. Field studies indicated that new wetlands flooded annually in fall or spring had greater forage production and quality, primarily due to spikerush enhancement at lower elevations, which led to greater cattle foraging. Landscape impacts of flooding also extended into adjacent uplands. Pintail and other species of waterfowl favored created wetlands, with the most Pintail under spring flooding.;A parallel study assessed the effects of flood cessation on forage, plant community and waterfowl use dynamics within wetlands previously dominated by cattail. While a change in seasonality of flooding from fall to spring had limited impacts, flood cessation for up to two years reduced waterfowl abundance and forage availability, and markedly altered wetland vegetation. Species diversity increased with drying, largely due to cattail decline and the release of invasive forbs. However, cattail reductions were only temporary, likely limited by soil moisture levels that remained above 5% during the study. While grazing affected many forage species, these effects depended heavily on flood regime and topographic position as well.;Overall, long-term strategies to prevent plant community succession to cattail should likely include cycles of flooding with intermittent flood cessation in new wetlands, while extended drying appears necessary to achieve significant cattail control on established wetlands.