Grays Lake Ecosystem

Shores: Sedge and grass meadows varying in width from a few rods to a half mile or more. Hay is cut from some of these bottoms but their chief use is as grazing land for stock especially sheep.

Bottom: Compact tule or sedge sod except in the open ponds where the firm mud bottom is covered with from 12 to 18 inches of black ooze.

Inlets: Springs and local drainage from the nearby mountains. Principal inlets are Willow Creek and Bridge Creek on the east and Gravel Creek on the south.

Outlets: Gray's Lake Outlet (or Bear Creek) leads from the northwest corner of the lake and is the only natural outlet. However, this natural outlet is now controlled by gates while a ditch (opened in 1924-25) at the southwest corner conducts surplus water into Meadow Creek and finally into the Blackfoot River Reservoir through Pelican Slough. Thus Gray's Lake becomes an auxiliary to the Blackfoot River Reservoir.

Water: The water is clear with a pH value of 7.3 to 7.6 and varies in depth from a few inches (marsh) to 3 feet in the open ponds.

Marsh:

• Bulrush (Scirpus occidentalis) - dense stands cover over 90% of the entire lake.
• Cattail (Typha angustifolia) - abundant about open ponds and along channels.
• Spikerush (Eleocharis palustris) - extremely abundant as a border (few yards to half-mile wide around the lake outside the marsh proper).
• Baltic rush (Juncus balticus) - broken bands along the higher ground back of the spikerush and scattered over the flooded meadow.
• Burreed (Sparganium) - abundant at the north end and east side at creek mouths and extending along channels into the marsh.
• Water plantain (Alisma) - common on flooded meadows and in semi-open water.
• Sedge (Carex nebraskensis) - dense patches about open water and scattered over the hay meadows.

  Other species on the flooded meadows were:

  • Marestail (Hippuris vulgaris) - common
  • Cicuta occidentalis - common to abundant
  • Triglochin maritima - abundant
  • Slender spikerush (Eleocharis acicularis) - abundant
  • Water smartweed (Polygonum amphibium) - frequent
  • Grasses common to abundant

Aquatic:

• Leafy pondweed (Potamogeton foliosus) - common to abundant in all open water.
• Variable pondweed (Potamogeton herterophyllus) - common to abundant in shallow water covering the grazed meadows and in the thin stands of bulrush, cattail, and spikerush but rare or absent in the small ponds as well as in the south lake.
• Water milfoil (Myriophyllum) - common to abundant in all open water.
• Common bladderwort (Utricularia vulgaris) - abundant in water wherever the marsh is thin; common in open water
• Coontail (Ceratophyllum) - common to abundant in the south lake and larger open ponds.
• Little duckweed (Lemna minor) - common to abundant in water wherever the marsh is thin.
• Star duckweed (Lemna trisulca) - common in the south lake and larger open ponds.
• Algae (Nostoc) - extremely abundant wherever there is water.

Submerged vegetation is of minor importance except in the 500-ac patch of open water at the south end. There, however, a fine stand of leafy pondweed, Myriophyllum, and coontail as well as floating and submerged duckweeds provides an abundance of succulent green foods to complement the vast quantities of grain produced in the marsh.

Summary

Gray's Lake is not a lake at all but a great marsh, covered with from few inches to 2-3 feet of water, in the center of which rises the mountain, Bear Island ¼ to ½ mile wide and 1½ miles long. At the south end of the lake a 500-ac expanse of water is dotted with little marsh islands. While small ponds and open channels are frequent long either shore. The interior of the lake is a broad and almost unbroken expanse of the big bulrush.

Wildfowl: Gray's Lake no doubt is frequented by all species of marsh birds that nest or migrate through the Rocky Mountain region of the United States. Mallards and teals are reported to nest in abundance in the marsh. In addition to broods of these ducks, other species seen during this survey were: gadwall, widgeon, pintail, mud hen, American bittern, jacksnipe, black tern, and yellow-headed blackbird. Gray's Lake produces an enormous surplus of wild duck foods.

Muskrats: Gray's Lake is a fine muskrat territory and probably the only serious opposition to making it a bird refuge will come from those people who have been accustomed to reap the annual fur harvest.