The Role of Waterfowl
and other Wildlife on
Aquatic Resources, Recreation, and Disease Transmission
Mike Adam
The interactions of humans with waterfowl and other wildlife in
and around natural aquatic systems are a common occurrence during the summer
months. While these interactions may be positive, problems inevitably arise,
particularly in urban areas. Many of the debates have stemmed from concern
regarding impacts on human health posed by wildlife that use urban lakes and
ponds. Often the habitats (i.e., standing water, wetlands, manicured lawns) in
and around these aquatic systems are identified as a source of these problems.
Potentially, serious health issues can occur if optimal conditions exist.
Examples of these issues in recent years include E. coli and West Nile virus. Public
education is critical to prevent over management of these natural systems. This
presentation will spotlight a few of these associations and discuss the impact
to public health.
Nutrient Reserves of Lesser Scaup during Spring Migration in the Upper Midwest: Influences of Wetland
Quality
Michael J.
Anteau and Alan D. Afton
Female lesser scaup
(Aythya affinis; hereafter scaup)
currently have lower lipid reserves than historical values during spring
migration throughout Iowa, Minnesota,
and North Dakota; females
currently are catabolizing lipids throughout this area, whereas we believe that
they should be gaining lipid reserves during spring migration in preparation
for breeding. Thus, lipid reserves of a large segment of the continental scaup
population has decreased, which may lower breeding
propensity and overall reproductive success.
Amphipods (scuds/freshwater
shrimp) are the preferred food of scaup during spring migration. Amphipod
densities currently are low throughout the upper Midwest
(1 – 12 m-3) and scaup concomitantly are consuming fewer amphipods
compared to historical records. Moreover, scaup probably now spend more time
searching for food within and among wetlands than they did historically. Fish
occurred in 74, 78 – 84, and 31 – 45% of wetlands in Iowa,
Minnesota, and North
Dakota, respectively, whereas historically they
occurred in only 10 – 20% of wetlands in the Prairie Pothole Region. Amphipod
densities were negatively correlated to fish densities and agricultural
sedimentation. We conclude that there has been a decrease in amphipod densities
throughout the upper Midwest, which is causing the
observed decreases in lipid reserves of scaup.
Our results indicate that wetland restoration efforts are
needed throughout the upper Midwest, but especially in Iowa
and southern Minnesota. Managers
should provide abundant populations of amphipods (over 26 m-3
geometric mean across the landscape) and target wetlands that: (1) have large
(> 500 m diameter) open-water zones, (2) are deep enough to support
over-wintering populations of amphipods, (3) allow management of fish
communities, and (4) have capability for managing the surrounding land to
reduce sedimentation.
The Use of Volunteer Data in Conservation Planning
George Cunningham
How Does Iowa’s Water Quality Rate?
Katie Foreman
Large quantities of water quality data on their own do not
inform water resources decision making and policy; these data have to be
analyzed, given meaning, and interpreted collectively in context in order to be
useful. The enormous benefit of water quality indices to water resources
management comes in their ability to distill large amounts of information into
a useful value that measures the health of the water resource. Water quality indices
help to answer the question: how good or how bad is the water quality in a
particular place and at a particular time? The Iowa Water Quality Index was
developed as a geographically specific, general-use water quality index to
represent a full range of water quality conditions in Iowa.
This presentation will discuss the development of the Iowa Water Quality Index
and results will be shared from applying the index to Iowa’s
ambient water quality data.
The Search for
the Needle in the Haystack – The Return of One of Iowa’s Lost
Mussels
Scott Gritters
Since 2001, over 10,000 walleyes, smallmouth and largemouth
bass have been stocked into the Iowa,
Cedar and Wapsipinicon Rivers
that were infected (inoculated) with the federally endangered Higgins eye
pearly mussel. This inoculation took place at the Genoa National Fish Hatchery
at Genoa, Wisconsin.
Once released, the fate of the Higgins eye was unknown. In August of 2005, a
team of volunteers, county, state and federal natural resource employees searched
stocked sections of these rivers to determine if any Higgins eye mussels had
transformed into juveniles. During the search, 2,394 mussels were collected of
27 species, including a single individual of the Higgins eye pearly mussel.
This specimen was collected on the Wapsipinicon
River near Central City, Iowa.
Several other state listed endangered mussels were also collected. Follow up
surveys are being planned for 2006.
Potential
Benefits of New Technology in Urban Watershed Modeling
Mike Hawkins
The Iowa Great Lakes is a 12,000-acre natural lake complex that
has long been recognized as one of the State’s most valuable natural and
economic resource areas. The preservation of these unique resources is a state
and local priority. Water quality in the Iowa Great Lakes is among the best in
the State and two of the lakes (Spirit
Lake and West
Okoboji Lake)
are drinking water sources for approximately 10,000 permanent residents and
over 1 million visitors annually. Major water quality concerns for the Iowa
Great Lakes are being addressed in two categories – agricultural and urban. An
extensive GIS watershed assessment for the
Iowa Great Lakes has been initiated to address these two components. The urban
component, as in many watersheds is becoming increasingly important to
understand. Locally, there has been a 22% increase in urban/residential area
over the past 8 years. Tools to address agricultural concerns are well known,
but new tools are becoming available to assess and lessen urban impacts and
prioritize drainage improvements. Our current assessment will use Light
Detection and Ranging (LiDAR) to acquire high quality elevation models to build
urban drainage networks and delineate urban watersheds. In addition,
high-resolution imagery will be used to delineate urban/residential land use
and imperviousness. Examples of the urban assessment will be shown, as well as,
how this part of the assessment will compliment a more traditional agricultural
assessment.
Collecting
Credible Water Quality Data from Remote Sites with Volunteers
Bernie Hermanson
This presentation will highlight a partnership volunteer water
monitoring program involving a Harlan high school chemistry class and the
Shelby County NRCS. In five years the project has progressed from students
collecting water samples to test in the lab, to students calibrating an
electronic multiprobe. The probe automatically tests the water every hour and
updates data on a web page every four hours. Examples of students involvement,
curricular injection, and both the low tech and high tech data will be
displayed. Future plans for the project will be announced.
Valuing Water
Quality Improvements in Iowa Lakes: Do People’s
Perceptions of Water Quality Match Physical Measurements?
Joseph A. Herriges, Catherine L. Kling, and John Downing
The Iowa Lakes Valuation Project is an economic study of the
use and value Iowans place on water quality in Iowa
lakes. A large sample of Iowa residents are being surveyed annually for four
years in order to collect detailed information from residents concerning their
pattern of lake recreational use, travel patterns, and preferences concerning
water quality changes. Combining the annual survey with a rich data set on
water chemistry, biological analysis, and GIS
data collected by Dr. John Downing has provided the research team with a unique
opportunity to study the linkages between water quality and the choice of lakes
residents visit. This data are also being used to quantitatively assess the
degree to which people’s perceptions of water quality match the objective
measures of water quality collected by the limnology team and the degree to
which water quality improvements might change visitation patterns.
Iowa Water Trails
Nate Hoogeveen
Water trails are a relatively new concept of considering rivers
and lakes in terms of linear experiences they offer to people who recreate on
the water. They are also at the intersection of economic development, concern
for water quality, and recreation in Iowa.
Restricting
Use of Phosphorus Fertilizers to Reduce Phosphorus Export from Residential
Areas
James Johnson
Phosphorus-containing lawn fertilizers are often implicated as
a key nutrient source contributing to the eutrophication of urban lakes, but
reliable quantitative studies linking fertilizer use to nutrient export in
actual residential areas are limited. We monitored stormwater runoff from six
residential watersheds in the suburban area west of Minneapolis,
MN during the non-winter months of the
five-year period from 2001 to 2005. Three of these watersheds were within the
city of Plymouth, MN, where the use
of phosphorus-containing fertilizers had been restricted since 1995, while the
remaining three were located in an adjacent city, Maple
Grove, which had no such fertilizer restrictions until
2004. Results from the first three years of monitoring indicated that the Plymouth
test watersheds experienced significantly lower phosphorus export than the
similar watersheds in Maple Grove. These results suggest that restricting the use of
phosphorus fertilizers may be an effective and low-cost best management
practice for reducing phosphorus export from residential areas. Additional
data from 2004 and 2005 are being used to assess any reductions in phosphorus
export resulting from phosphorus fertilizer restrictions enacted by the Minnesota
state legislature in 2004.
Implementing
the FAIR Approach to Clean Water (Filter, Absorb, Infiltrate to Retain 1” Rain)
Stacie Johnson
FAIR is an acronym for Filter,
Absorb, Infiltrate to Retain the one-inch rain.
FAIR is a pilot project funded by the Environmental Protection Agency,
Region VII Water Quality Cooperative
Agreement and has three elements:
1)
Facilitate FAIR Technical Policy Development
2)
Conduct “Fundamentals of FAIR” Training
3)
Perform Property Owner Outreach & Education
Trout Response
to Water Quality Changes in Iowa
Bill Kalishek
Iowa's
populations of wild trout have expanded rapidly over the past three decades. In
1980, there were only six trout streams in northeast Iowa
that supported wild, naturally reproducing populations of trout. Today there
are 27 streams that support populations of wild trout. Additional streams that
historically supported warmwater fish assemblages now have changed to
supporting coldwater species. Land use changes in the watersheds of trout
streams have been the major factor in these water quality changes that now
allow trout survival.
New Developments on Integrated Watershed Modeling
Thanos Papanicolaou
Watershed related processes are non-linear in nature due to complex
interactions in pedology, geology, biology and
hydrology and remain all-together a challenging problem with several societal
implications. Some of the perplex
questions associated to watershed processes include: (1) the effects of scale
in monitoring and modeling; (2) the integration of all phases (i.e., surface
and subsurface) in monitoring and modeling; (3) the effects of land-use on
geomorphic changes in aquatic environments; (4) the cause and effect relation
in the biotic and abiotic constituents of a
watershed; and (5) the development of economic and environmental indicators for
alternative scenarios and modeling assessment purposes.
Recognizing the
critical need for developing an integrated and scientifically sound framework
in watershed research, interdisciplinary groups began to emerge that expanded
beyond traditional discipline -boundaries and reached out to other areas of
expertise. For example:
-in the area of computational hydraulics efforts were
undertaken to couple 3-D hydrodynamic models with Large Scale Gridded River Networks (e.g., Olivera
and Raina, 2003).
-in the area of upland erosion efforts were undertaken to
incorporate upland erosion processes-based models with GIS tools (e.g., Flanagan et al. 2004).
-in the area of eco-hydraulics new metrics were developed
for quantifying the effects of natural and anthropogenic impacts on habitat
(e.g., Papanicolaou et al. 2003).
-in the area of hydroinformatics
pilot decision making systems were developed for real-time control of urban
drainage systems (e.g., Abbott 1994; Goodwin 2000).
-in the area of watershed management environmental and
modeling system were constructed for performing watershed assessments (e.g., Gassman et al. 2002).
-in the area of watershed modeling optimization
algorithms for parameter estimation were deduced (e.g., Gupta et al. 2003)
At the governmental
level, this integrative research was triggered by the NSF with programs such as
the “biocomplexity in the environment” that promoted
collaborative research for biological processes in aquatic environments; the
IGERT program that fostered interdisciplinary graduate research and teaching in
all disciplines including water resources; and the Information technology
research (ITR) program focused on the creation of distributed grids and computer
infrastructure for different disciplines.
The watershed research program that was initiated by the US EPA and
supported by the NSF and USDA constitutes the most known orchestrated effort in
the United States, so far, for advancing understanding
of natural phenomena and processes within a watershed (Diplas,
2002).
Although the above
efforts have succeeded in promoting multidisciplinary interactions and prepared
the grounds for future improvements in the simulation of complex processes such
as watershed processes, a new paradigm shift that enables dynamic simulation of
these processes is necessary. The novel
capabilities to be sought here are application simulations that can dynamically
accept and respond to on-line field data and measurements and/or control such
measurements. This synergistic and
symbiotic feedback control-loop between simulations and measurements is a novel
technical direction that can open domains in the capabilities of simulations
within watersheds that can facilitate the “capturing” of episodic catastrophic
events.
Many watershed
simulations today work in the batch world: an event is simulated based on a
static set of field data. If newer data
become available, the simulation is simply rerun. For example, hydrodynamic and sediment
transport simulations to predict geomorphologic changes within a stream and the
impact of these changes to the aquatic life are conducted by considering a
constant sediment input value from terrestrial sources such as roads,
floodplains, and other natural occurring disturbances (i.e., landslides,
fires). As a result perturbations that
exist in the system due to the spatial and temporal variability in the
terrestrial sediment input are not accounted.
Very few applications use real time data even if the capability to do so
is available. A great effort has been
recently devoted to run simulations faster than real time based on static data
sets. However, this is highly
inefficient and leads to multiple sediment predictions that are conflicting
when major events are predicted. This
lack of ability to dynamically inject data into simulations and other
applications, as these applications execute, limits the analysis and the predictive
capabilities of these applications.
The foregoing thoughts suggest that, despite the improved knowledge gained
in the general area of watershed research and management (e.g., Diplas 2002), there remain several significant questions
regarding dynamic simulation of these processes as it
was defined earlier.
Implementation of the current ideas for
solving several practical problems of a watershed scale has not been
straightforward.
Ducks Unlimited’s Living Lakes Initiative
for Iowa – Emphasis on Larger Marshes
Roger Pederson
Lying between the Mississippi
and Central Flyways, Iowa’s
remaining wetlands are particularly important for migratory birds and resident
waterbird breeding populations. Of the few remaining wetlands, most are
experiencing an ongoing and gradual decline in their ecological condition.
These losses and impacts have severely reduced the capacity of the habitat to
provide food resources for the millions of birds that depend on these wetlands
during spring, summer, and fall. Ducks Unlimited plans to restore large marshes
and improve existing marshes to a more ecologically productive condition
through its Iowa “Living
Lakes” initiative.
Central to the Living
Lakes program is the protection,
restoration, and enhancement of large wetlands and shallow lakes. Conservation
efforts to protect watersheds of larger wetland basins are encouraged. On
larger projects, “functional restoration” is employed to ensure the restored
hydrology will allow development of appropriate emergent and submergent
vegetation zones in these shallow lakes. Typically, engineering activity
(survey, design, construction of water-control structures, etc.) is required to
restore the biological productivity to many larger basins.
The Iowa River Greenbelt Water Trail
Rod Scott and Duane Rieken
This program
will provide attendees with a brief overview of the more than 15 years of
development of the Iowa River Greenbelt. Since Pammell, the father of Iowa's
State Park system, documented the incredible natural resources in the 1920's
and others documented the American Indian sacred sites, the Iowa
River has been recognized as a special place. In the depths of the
farm crisis in the 1980's citizens along the river established the boundaries
of and use plan for the Iowa River Greenbelt. Since that time, the Hardin
County Conservation board established the water trail and now manages multiple
sites along the river. The Iowa River Greenbelt Resource Trust, a special
committee of the Iowa Natural Heritage Foundation, has been involved with many
projects over the years with the Hardin County Conservation Board and the Iowa
Department of Natural Resources. In 1996 the area was included in the Federally designated Silos and Smokestacks National Heritage
Area. The area holds the important story of the American agricultural
experience.
The recreation opportunities on our river and at Pine
Lake State Park
support the quality of life for our residents as well as providing a tourism
resource for us to bring visitors to our area. These visitors have a positive
economic impact in our rural communities. We will discuss the importance of
good water quality for our river users, the importance of working together with
the agriculture industry and communities along the river.
The Lake Ahquabi Restoration
Story: Combining In-lake Efforts to
Provide Water Quality with Watershed Efforts to Ensure Longevity
Randy Schultz
Lake Ahquabi is a 44 hectare
impoundment constructed in 1935 located in south-central Iowa
with a watershed of 1,335 hectare. Rehabilitation efforts at the lake and its
watershed occurred in the mid 1990s and included total fish renovation,
construction of five sediment/nutrient control basins and increasing the size
of an existing basin, dredging, spillway reconstruction including a new water
control structure, shoreline protection, fishing jetty construction, handicap
accessible enclosed fishing pier and placement of fish habitat. The project was
assessed by routine water quality monitoring, fish population sampling, creel census and watershed analysis through the Agricultural
Non-Point Source Pollution model (AGNPS). Water samples taken from 1997 through
2003 show significant reductions of mean Chlorophyll A, Total Nitrogen, Total
Phosphorus, and Total Suspended Solids (TSS)
compared to concentrations recorded at the same sampling sites in 1990.
Watershed analysis using AGNPS indicated sediment delivery to the lake was
reduced by 43%. Since renovation, fishing effort has nearly doubled; last year
angling pressure was nearly 300 hours per acre.
Biological Impacts of Hurricane Katrina on the Gulf Coast
Gregory J. Smith
With more than two decades of hurricane-related experience, the
USGS National Wetlands Research Center (NWRC) immediately responded to
Hurricane Katrina by using specialized technology, aircraft and vessels.
Scientists at NWRC assisted in post-Katrina boat rescues and humanitarian
relief, geospatial database and map production for emergency response, and
aerial reconnaissance and ground surveys of coastal impacts. The social and biological landscapes were
severely damaged over a multi-state region by wind, surge and flood.
Post-Katrina overflights and satellite imagery showed that marshlands and
barrier islands east of New Orleans
and the Mississippi River were severely scoured by
Katrina’s surge, further reducing their buffering capacity to protect coastal
communities from future storm surges. Forest resources,
particularly hardwoods, within the high-wind swath of Katrina suffered major
blowdowns of canopy trees and leaf and branch stripping of standing survivors.
The newly open canopies are expected to stimulate regeneration of the invasive
tree species Chinese tallow and increase its dominance, thus reducing wildlife
habitat quality of these coastal forests. Doppler-radar imagery of migratory
bird movements before and after Katrina showed a dramatic shift in habitat use
away from coastal wind-ravaged hardwood forests to more inland and low-impact
pine forests. Radar monitoring of bird density patterns will continue through
fall migration to determine the implications of wide-area destruction of prime
staging habitat on transgulf migration patterns and survivorship. By using
NWRC’s advanced spatial databases and hurricane modeling tools, field studies
in forest, marsh, and seagrass habitats will be conducted to relate storm
forces to landscape-scale patterns and processes of habitat alteration.
Post-Katrina studies are expected to advance current knowledge about the role
wetlands play in mitigating storm impacts and sustaining fish and wildlife
resources.
Using Volunteer-Collected
Transparency Tube Data in Minnesota Stream Turbidity Assessments
Laurie Sovell
Collaboration among professional and volunteer monitoring
networks is a core concept in the Minnesota Pollution Control Agency’s (MPCA)
monitoring strategy. As a reflection of this, volunteer collected Transparency
tube (T-tube) data are now used by the MPCA to help assess water quality and
determine impairments.
The MPCA’s Citizen Stream-Monitoring Program (CSMP) began in 1998 with
the goal of giving individuals across Minnesota
an opportunity for involvement in a simple, yet meaningful volunteer
stream-monitoring program. Once enrolled, CSMP participants visit an
established spot on a nearby stream once per week from April to September to
measure Stream Transparency, Water Level (Stage), Appearance, and Recreational
Suitability. To encourage stream monitoring immediately after large rain events
whenever possible, volunteers record daily rainfall at their homes.
Large data sets indicate that transparency values collected by
CSMP volunteers reliably predict turbidity - a parameter for which Minnesota
has a state water quality standard. These correlations allow the MPCA to use
transparency as a surrogate for turbidity where there are not enough turbidity
observations to meet 305(b) and 303(d) assessment criteria. Specific guidelines
for using T-tube data in assessments have been developed. For the 2006
assessments, a total of 88 stream segments were assessed using T-tube data. Of
these, 55 new segments are proposed to be listed as impaired for turbidity
based entirely or in-part on T-tube data. Another 28 segments are proposed to
be listed as fully supporting of the turbidity standard. To date,
14% of lakes and 8% of stream segments in Minnesota have been assessed. The addition of Citizen
Stream-Monitoring data to the assessment process will greatly augment the
state’s ability to meet its goal for assessing water resources.
Floods, Droughts, and Our Increasingly Erratic Weather
Elwynn Taylor
You need not be old to remember when "200-year
floods" were more than 27 years apart.
It was not so long ago, but the climate was different then. Since 1950
the average annual precipitation in Iowa
has increased by 10%. Similar increases were logged for many other Midwest
States. That increase essentially doubled the annual stream flow in much of Iowa
and the rivers were accordingly over flood level 5 to 8 times as often. The
increased precipitation has contributed to a westward expansion of the Corn
Belt but the incidence of drought and other forms of extreme
weather seems to have increased as well.
There is a periodicity to our weather. Although drought
develops about one year in six it is not uncommon to experience 12 to 20
consecutive drought-free years. Nor is it uncommon to have two or three serious
droughts within a six-year period. A dry/wet cycle averaging about 18.6 years
impacting the year-to-year market value of grain over several decades was
observed in 1885. The assumption that the pattern would persist proved accurate
through the 1900s. Iowa tree-ring records indicate that
the weather cycle is a longstanding attribute of our climate.
Our climate is changing. Climate has always changed. Widespread
changes seem to be associated with anomalous temperatures of the sea surface.
Erratic weather appears to be the primary manifestation of a warming climate.
Coincidence of the high-risk years of the 18.6-year cycle, the tropical storm
cycle, and the La Niña gives a likelihood of escalating extremes of weather in
the next few years.
Along the Skunk: County
Water Trail, Grant Improvements, Baptisms and Nesting Eagles
Greg Vitale
Rivers are natural corridors, some of the last in Iowa.
They link communities-towns along the way, their histories and the people in
the towns to the outdoors. The Skunk River corridor, its tributaries and
adjacent greenbelt trails and parks are used by a diverse group of people for
recreation including swimming, canoeing, kayaking, fishing, mountain biking,
bird watching, cross country skiing, horseback riding, snowmobiling, and
hunting, as well as for education and research. The on-going water trail
grant’s safety, access and sign improvements are creating more local
opportunities for people to get outdoors and enjoy the river and in its
adjacent parks. These quality of life, and consequently economic development,
issues depend on and are enhanced when we help people connect to the river
corridor’s local recreational opportunities.
Ecological
Wastewater Management in Iowa: Hope for Iowa’s Small Communities
Scott Wallace, Gene Parkin, Brett Ballavance, and Ryan Brandt
The discharge of untreated or partially treated sewage into
lakes and streams is a major pollution problem in Iowa.
IDNR has recognized this as the number-one threat to Iowa’s
surface waters from point-source discharges. It is currently estimated that
there are 739 unsewered communities in the state which collectively discharge
1.2 billion gallons of inadequately treated sewage each year into the waters of
the State. Fixing this problem is projected to cost between $214 and $322
million dollars. Similar problems exist in other Midwestern states, including Minnesota
and Indiana.
Many new technologies for collecting, treating, and disposing
of wastewater are now available. These technologies include alternative sewers,
constructed wetlands, enhanced pond systems, media filters, drip irrigation,
and effluent reuse. These technologies
offer the best solution to providing cost-effective wastewater services to the
small communities left behind by more conventional engineering approaches.
However, a number of policy factors limit the use of these systems, including a
lack of responsible management entities, regulatory procedures, and a lack of
education and training among wastewater professionals. This presentation will
examine issues limiting the adoption of alternative wastewater systems and will
offer recommendations on how to address these policy issues.
Iowa Groundwater
as a Drinking Water Source: What are the Health Issues?
Peter Weyer
Water quality problems in Iowa’s
lakes, rivers and streams are well documented and are a high priority issue for
the state. While the focus is mostly on recreational use, drinking water
derived from Iowa water sources
is potentially a much greater public health concern. Surface water sources
provide drinking water for only about 20% of Iowa’s
population; the other 80% get their drinking water from groundwater sources.
While most groundwater users rely on municipal water utilities, about 240,000 -
250,000 Iowans use private wells for their drinking water. This talk will
present the current issues in Iowa
groundwater quality, particularly as they relate to private drinking water
wells. Emerging issues such as herbicide metabolites, arsenic, and perchlorate will be discussed. Potential health
implications of exposure to these contaminants via drinking water will be
covered. Also presented will be a brief overview of options well owners have if
their well water is contaminated, and suggestions for policy directed at
groundwater protection
The Iowa Beach Study
Eric O’Brien and Peter Weyer
Protecting swimmer health is a primary goal for the state of Iowa.
For this reason, Iowa’s State
Park beaches have been monitored weekly since 2000 for indicator bacteria as
part of Iowa’s Ambient Water
Monitoring Program, in accordance with suggested guidelines recommended by the
U.S. Environmental Protection Agency (EPA). However, the recommendations from
the EPA were not based on the types of water resources that we typically see in
the Midwest. Because of this fact and to better protect
the health of swimmers at Iowa’s
beaches, a pilot study of beach users at three eastern Iowa
beaches was conducted to determine the rates of self-reported gastrointestinal
illness or symptoms in swimmers and in non-swimmers. The rates of reported
illness were then correlated with bacterial levels in the beach water. A total
of approximately 1000 persons were recruited at West
Overlook Beach,
Sandy Beach (both at Coralville
Lake), and at Lake
Macbride Beach
in Johnson County
between June 15 and July 31, 2005.
Study staff visited beaches daily to distribute informational flyers, recruit
participants, and take water samples. Participants were then enrolled in an
on-line, web-based system to collect health information weekly over a four-week
period. Preliminary results from the study will be presented and plans for
future beach research will be discussed.
The Role of Fishes in Shallow Lakes
Kyle Zimmer
We measured algal abundance in 72 shallow lakes across two
biomes (prairie and deciduous forest) in western Minnesota (USA) during the
summer of 2005. We also determined the type of fish community and fish biomass
present in each site and used GIS to estimate the proportion of land used for
agriculture within a 500 m buffer around each lake. We used a model-selection
approach to assess the relationships between algal abundance and a) biome, b)
agriculture use in buffers, and c) several characteristics of the fish communities.
The model best supported by the data had terms for biome and total
benthivore-planktivore biomass and explained 60% of the variance in algal
abundance. This model had 3-fold stronger support than the second best model
(total benthivore-planktivore biomass interacting with biome), and
>1000-fold stronger support than the top agriculture model (agriculture
interacting with biome). Our results indicate that management of Minnesota’s
shallow lakes should expand beyond anthropogenic effects on watersheds to include
the management of fish populations within these systems.
