HomeMy WebLinkAboutWATERGLEN PUD PDP - 71 93A - CORRESPONDENCE - WILDLIFE DOCUMENTS (6)STATE OF COLORADO
Roy Romer, Governor
DEPARTMENT OF NATURAL RESOURCES
DIVISION OF WILDLIFE
AN EQUAL OPPORTU rry OdPLOYER
Perry D. Olson, Director
6060 Broadway
Denver, Colorado 80216
Telephone:(303) 297-1192
Mark Leslie
Colorado Division of Wildlife
317 W. Prospect Rd.
Fort Collins, Co 80526
Dear Mark:
Wildlife Research Center
317 West Prospect Road
Fort Collins, CO 80526
(303) 484-2836, ext. 342
November 16, 1993
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I wanted to take a minute to summarize my thoughts on the impacts of the proposed residential
development around Cooper Slough north of Vine Drive. Our field trip this morning reinforced my earlier
impressions that this slough is critical waterfowl habitat for the Fort Collins vicinity: I estimate that about
200 mallards were flushed from the slough this morning. However, this number represents only a fraction of
the use this area would receive during the depths of winter, when upwards of several thousand ducks may
use this wetland. The size of the wetland area belies it's relative value to the region, because the water flow
for the slough originates from a warm -water spring source. Although less than 1 % of the wetland area in
eastern Colorado is classified as warm -water sloughs, they offer vital roosting, foraging, and courtship
habitat at a time of year when wetland resources are limiting. I have enclosed a copy of a chapter I�
authored on wintering waterfowl ecology that explains in more detail the value of warm -water sloughs in the
winter ecology of waterfowl on the High Plains.
In addition to the open water provided by the slough, watercress (Nasturtium officinale), the dominant
aquatic plant in Cooper Slough, is an important vegetative food for mallards as well as an excellent
substrate for aquatic invertebrates, particularly snails (Phvsa spp.). During winter, ducks are dependent on
supplemental aquatic plant and invertebrate foods to balance their diet, which is dominated by nutritionally -
deficient cereal grains such as corn.
. I envision several potential negative consequences to Cooper Slough as a result of the proposed.
residential development. Eutrophication of the wetland is likely to result from nitrogen and phosphorous
laden runoff from fertilized lawns and gardens. Additionally, salts from runoff in the winter will increase
salinity. These combined effects are likely to alter the aquatic plant (and associated aquatic invertebrate)
communities to emergent plant forms that are better suited to eutrophic systems, such as cattail. Given the
shallow water depths and the prevalence of cattail in the seedbanks of eastern Colorado, my prediction is
that Cooper Slough will change from a wetland dominated by submergent watercress with significant
amounts of open water, to a cattail choked waterway with little open water. The effect of the cattail
invasion, coupled with the construction of a detention pond in the existing waterway, will slow the water
flow through the slough. When warm -water sloughs are impounded and/or flows are slowed, the usual
result is increased cooling of.the water and eventual freezing of the wetland. The combined loss of open
water habitat, together with elimination of food plants and invertebrates, will destroy the very qualities of
the slough which now make it important to waterfowl. Unfortunately, these detrimental effects will
undoubtedly affect the undeveloped portion of the slough south of Vine Drive as well.
I wish I could paint a prettier picture, but this is my best professional opinion about the likely effects of
the development on Cooper Slough. Feel free to contact me if I can be of any further help on this issue.
Sincerely,
J es K. Xing , Ph.D.
Wildlife Researcher
DEPARTMENT OF NATURAL RESOURCES, Kenneth Salazar, Executive Director
WILDLIFE COMMISSION, Thomas M. Eve, Chairman • Louis F. Swift, Vice Chairman • Arnold Salazar, Secretary
Jesse L. Boyd, Jr., Member • Eldon W. Cooper, Member • Rebecca M. Frank, Member • William R. Hegberg, Member • Mart LeValley,
Member