Emergent Aquatic Pond Margins and Open Water Communities

(Collectively, management unit 32)                                    18 acres

The open water areas and drawdown margins of the 22 constructed and natural ponds occurring throughout the Preserve are critical elements for waterfowl production and provide habitat for several migratory bird species.   Most of the ponds are equipped with waterfowl brooding boxes. In 2009, the most abundant aquatic vascular plant species present within the ponds of the   east valley were sago pondweed (Stuckenia [Potamogeton] pectinata), floating‐ leaved pondweed (Potamogeton natans), coontail (Ceratophyllum demersum), and duckweed (Lemna spp. and Spirodela polyrhiza). The ecologically invasive curly‐leaved pondweed (P. crispus) and watercress (Nasturtium officinale) occur in low to moderate abundance in some of these ponds. The gradually sloping banks of these scrape ponds enhance wetland plant diversity at the Preserve by creating coenoclinal (hydroseral) banding of vegetation in response to water depth. Emergent aquatic and sedge meadow species sort out along water‐depth gradients, resulting in concentric rings of vegetation surrounding the pond margins. These pond margins support several species of emergent aquatic plants, some of which are important food sources for waterfowl, including arrowheads (Sagittaria latifolia and S. rigida), and several species of smartweed (Polygonum spp.).  Additional emergent aquatic species that are common around pond margins include soft‐stemmed bulrush (Schoenplectus tabernaemontani [Scirpus acutus]), river bulrush (Scirpus fluviatilis), broad‐leaved cattail (Typha latifolia), giant bur‐reed (Sparganium eurycarpum), water plantain (Alisma subcordatum), and lake sedge (Carex lacustris). One Wildlife Action Species (mallard, Anas platyrhynchos) and four Special Concern species (blue‐winged teal (Anas discors),

great egret (Ardea alba), great blue heron (Ardea herodias), and snowy egret (Egretta thula)) have been observed using these open water communities during their spring and autumn migrations. Typically, a given waterfowl species produces several broods during a given season, and the open water habitats of the Preserve contribute to North America’s waterfowl production potential.

Summary of Ecological Management Goals for Emergent Aquatic and Open Water Communities

  • Reduce or eliminate populations of high‐impact invasive species
  • Establish and maintain vegetative cover that can be utilized by waterfowl for food, bedding, and/or nesting substrates.
  • Establish and maintain waterfowl brooding boxes to benefit waterfowl production capacity.
  • Take measures to maintain or increase waterfowl production.
  • Catalog species richness across all trophic levels and enhance habitat quality to maximize species richness and diversity.