  
Aquatic and Beach Communities
Aquatic Habitats found on the area include Fish Lake (a large shallow sand-bottomed
lake), Beckman Lake and Cedar Bog Lake (two bog-margined lakes), Ice Lake,
Beaver Pond, and several other smaller permanent ponds that are bounded
by emergent marsh. A number of ordinarily temporary/vernal ponds or pools
are also found on the Area. Finally, Cedar Creek is a small meandering
muck-bottomed stream that is bounded by sedge fen and shrub swamp.
Each of the larger bodies of water has its own unique character and
will be considered separately.
Cedar Bog Lake lies in
a swampy matrix of white cedar swamp and is surrounded by a mat of Decodon
verticillata (Swamp Loosestrife). This late-flowering species turns
crimson in the fall and is a species of special concern in Minnesota.
It is found primarily at a few shallow lakes on the Anoka Sandplain.
This is the lake where Raymond Lindeman did his pioneering work on trophic
dynamics in aquatic ecosystems. According to Dr. Eville Gorham it
might more properly be called 'Tamarack Swamp Pond' as it is rather
small, not really a bog, and is immediately bounded by tamaracks.
Another name that has been proposed is 'Decodon Pond' emphasizing the importance
of this uncommon plant. Water, though dark-stained, is circumneutral.
Only stunted bullheads, tiny sunfish, and sticklebacks are found in this small, shallow, muck-bottomed lake. Waterfowl generally
ignore it, but occasionally otter will visit it from the creek nearby.
It and the surrounding swamps have received the attention of several paleobotanists
including Herb Wright and Ed Cushing.
Fish Lake is large (ca 3 mile
perimeter), shallow (90% less than 2 meters deep), and sand-bottomed along
the east shore while muck-bottomed along the western shore. Shallows
of the mucky western portion support a population of Zizania
palustris (Wild Rice). Nymphaea tuberosa, Nuphar luteum, and Brasenia schreberi (White and Yellow Water Lilies, Water Shield)
grow luxuriantly from this mucky substrate. A typical spectrum of
submerged aquatics is present.
Circa 7 species of Potamogeton are found in the lake. P.
amplifolius is the most common. Najas flexilis (Water Naiad)
forms an impenetrable mass below the Pondweeds. Other common submerged
aquatics are Utricularia vulgaris (Bladderwort), Ceratophyllum
demersum (Coontail), Elodea canadensis (Elodea), Myriophyllum
sibiricum (Water-milfoil), Vallisneria americana (Tape
Grass), Ranunculus flabellaris (Yellow Water Crowfoot). Off
the sandy east shore we find Scirpus validus (Softstem Bulrush), S.
acutus (Hardstem Bulrush), S. pungens (Three-square Bulrush),
and three species of Arrowheads (Saggitaria latifolia, S. cristata,
S. rigida).
Special Feature
During periods of low water an expanse of sand
beach is exposed along the shoreline of Fish Lake where one encounters
a dizzying array of plants. Heteranthera
dubia (Water Star Grass) and Hemicarpha micrantha grow on
a lush carpet of the tiny Spike Rush, Eleocharis acicularis. Several
other species of Eleocharis are present as well as species of Juncus (tenuis, nodosus, pelocarpa) and Cyperus (diandra, engelmanni, xx).
In later summer the shoreline is brightened by such species as Eupatorium
perfoliatum (Boneset), Verbena hastata (Blue Vervain), Lobelia
siphilitica (Blue Lobelia), Mimulus ringens (Square-stem Monkey
Flower), and Agalinis tenuifolia (Gerardia).
Vertebrates of Fish Lake
Fish Lake is in some sense a misnomer. Because it is so shallow,
it suffers periodic winter kills of most fish inhabiting it. Indeed,
from 1973 to 1983, there were no fish in it at all, only mudminnows and sticklebacks. However, it was an enormous breeding pond
for dragonflies. Millions of individuals of three species
(Epitheca spinigera, Ladona julia, Gomphus spicatus) would emerge
from this lake during a brief period in late May. They dominated
the lake until 1983. Since then the lake has undergone several cycles when
fish were abundant or scarce. Ca. 1985 bluegills, pumpkinseeds and to a lesser extent crappies were abundant. Ca. 1988 largemouth
bass dominated the lake and consumed everything else in it. In
the early 1990's the lake was again fishless. The latter half of
the 1990's saw an explosion of green sunfish. They were so
numerous that one could literally dip net them from the lake. Presently
(2001) they too have died out and the lake has again become a prolific
producer of dragonflies.
A canoeist on the lake will undoubtedly spot numerous painted turtles sunning themselves on uprooted lily root-stocks during the summer, and
on more than one occasion I have been startled by a monster snapping
turtle swimming in the shallows.
Every year since 1973 a single pair of Common Loons has attempted
to nest on the lake. About half the time they succeed in producing
one or two young. Infrequently, one witnesses spectacular chases
as two pairs contest for the lake soon after ice out in mid April.
Other birds of note are Great Blue and Green Herons, Belted Kingfishers,
Sora and Virginia Rails. Canada Geese began nesting on
the lake ca 1990 and have gradually increased in abundance, but do not
reach the pest proportions found on many city area lakes. Occasional visitants
to the lake are Bald Eagle, Osprey, and Trumpeter Swans. Black
Terns nested on the lake for a brief period during the mid 1970's.
The lake sees an influx of migrating waterfowl during spring and fall (incl.
bluebills, hooded mergansers, buffleheads, pie-billed and eared grebes,
coots....)
The lake has always supported at least one family of beaver.
Position of the lodge(s) changes over the years. Infrequently there is
an explosion of muskrat that exploit the cattails of Peterson Marsh
bounding the lake on the west. Otter occasionally visit the
lake in the fall for a sunfish snack.
Beckman Lake is most noteworthy
for its floating mat margin of sphagnum moss (Sphagnum spp) with
numerous species of graminoids, ericaceous shrubs, and carnivorous pitcher
plants and sundew. (See Section on Sphagnum Communities.)
The best bog margins of the lake are found in the southwest corner and
at the extreme north end. The entire eastern shore is fronted by
private land. Several of these homeowners have dug artificial ponds
in the marshy margin of the lake. These ponds are bermed, but they
do pose a threat to the fragile, nutrient poor communities found along
the lake's perimeter. Among the more noteworthy aquatics in the neutral
waters of the lake are Scirpus subterminalis and Equisetum fluviatile.
Beaver Pond is surrounded by emergent marsh (primarily sedge
and cattail). Two featurse of note are the presence of Pontederia
cordata (Pickerelweed) and a respectable patch of Equisetum fluviatile (Water Horsetail). During mid-summer the entire surface of this pond
is choked with Nuphar luteum (Yellow Pond Lily). It is an
excellent waterfowl hangout in the fall when ducks are chased from Fish
Lake by hunters.
Temporary Ponds are fringed by
a variety of wide-bladed sedges. Some of the more common are C.
lacustris, C. rostrata, C. comosa .... In early April these ponds
ring with the sound of spring peepers, chorus frogs, and woodfrogs. Chorusing can be so loud as to be almost deafening.
Soon thereafter one hears the less cacaphonic trilling of green tree
frogs and American toads. If these ponds dry out in mid
summer they become production centers for species of Bidens (Beggarticks)
and Polygonum (Smartweeds). A stroll through them at this
time is sticky business.
Cedar Creek is of rather
ordinary character although the views it offers a canoeist can be superb.
The broad basin, margined in sedge fen and shrub swamp, gives way in the
distance to golden tamarack (in late fall), white cedars, and pine covered
ridges. One can easily imagine being in some remote area of northern
Minnesota. A skier along the snow-packed marsh margin of the creek
on a mild winter day will likely encounter otter slides, and if
extremely lucky, otter themselves. On more than one occasion we have
been tempted to canoe the creek on a warm sunny day in mid February only
to be foiled by ice-covered meanders in its mid-section. Extracting
oneself from this predicament is no easy task as some of the gullibles who have accompanied us can attest. Several beaver dams are
additional obstacles encountered on a trip down the creek. But these
inconvenient portages are made up for by sightings of Blandings turtles along the way. During mid-summer extensive mudflats are exposed along
the creek's many meanders and these are alive with the mating antics of dragonflies like the ebony jewelwing (Calopteryx aequabilis), the white-tail
(Plathemis lydia) and the 10-spotter (Libellula pulchella).
Cedar Creek joins the Rum River ca 8 miles to the southwest and the Rum
eventually drains into the Mississippi River near Anoka. In addition to
myriad minnows and numerous carp, anglers occasionally catch a respectable smallmouth
bass, walleye or northern pike from the creek.
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