Introduction: The ecology of a river floodplain and the Emiquon preserve
Introduction: The ecology of a river floodplain and the Emiquon preserve
0 J. W. Walk The Nature Conservancy , 240 SW Jefferson Street, Peoria, IL 61602 , USA
1 M. J. Lemke (&) Biology Department, University of Illinois Springfield , MS HSB 223, One University Plaza, Springfield, IL 62703-5407 , USA
2 Guest editors: Michael J. Lemke, A. Maria Lemke & Jeffery W. Walk / Large-Scale Floodplain Restoration in the Illinois River Valley , USA
3 R. E. Sparks Illinois Natural History Survey , Champaign, IL 61820 , USA
4 A. M. Lemke K. D. Blodgett The Nature Conservancy, Illinois Rivers Office at Emiquon , 11304 N. Prairie Road, Lewistown, IL 61542 , USA
Scientific study of the Illinois River began before a century of anthropogenic change, thus providing a unique perspective for describing river ecology restoration. In this issue, we explain how systematic monitoring revealed patterns in the restoration of the 2723-ha Emiquon Preserve on the Illinois River. The papers describe (1) how planktonic microorganisms, vegetation, fish, and waterbird communities responded rapidly to flooding of former shallow lakes and wetlands that had been drained and used for dryland agriculture for 83 years; (2) how variation of hydrologic conditions favors biotic community diversity and conditions for carbon sequestration; (3) how fish populations imposed a trophic cascade and affected diversity, yet may not help control some undesirable fish species; and (4) how simulation models are useful in planning, but that restoration practice and management decisions must adapt to present conditions, involve trade-offs, and are influenced by competing stakeholder interests. Unsurprisingly, water level management remains the most important factor in the restoration ecology of floodplains; however, the establishment of a river-floodplain connection should be managed to achieve a balance between establishing hydrology that mimics natural flood pulses while minimizing contemporary threats, including excessive nutrient and sediment loads and invasive species.
River; Restoration ecology; Ecological attributes; Shallow lake; Flood pulse
Alterations to the Illinois River and its floodplain and
watershed began relatively late (1800s) and occurred
rapidly when compared to similar modifications in
large rivers. One advantage of the relatively recent
changes to the Illinois River was the establishment of
the Illinois Natural History Survey (INHS) field
station along the middle reach of the river where the
Emiquon Preserve exists today (Fig. 1). Under the
direction of Stephen A. Forbes, a team of scientists
conducted systematic field studies of hydrology,
chemistry, and biology that documented the
productivity of the Illinois River prior to significant
alterations for navigation, agriculture, and urban
(Starrett, 1972; Schneider, 2000)
extensive historic scientific documentation
Forbes, 1876, 1888; Hart, 1896; Kofoid, 1903; Forbes,
1907; Forbes & Richardson, 1908)
exists for few other
Commercial development and engineering of the
Illinois River was swift; however, so was the rise of the
U.S. conservation movement in the 1920s and the
subsequent environmental movement in the late
1960s. Conservation policies restored 8% of the
floodplain wetlands along the Illinois River that had
been leveed and drained, and preserved over 90% of
the original floodplain in the northern part of the Upper
Mississippi River as U.S. National Fish and Wildlife
(Scarpino, 1985; Thompson, 2002)
Environmental policies vastly improved water quality in both
rivers, required federal agencies to assess
environmental impacts of river development projects, and led
to a cooperative federal–state program (the Upper
Mississippi River Restoration Program, UMRRP) that
has monitored natural resources and restored degraded
habitats in both rivers for over 30 years (USACE,
2016). The INHS has continued to study the river
during these periods of change, participating in the
UMRRP and documenting the recovery of fish and
(Sietman et al., 2001; McClelland
et al., 2012)
The Nature Conservancy (from here,
‘‘Conservancy’’) has played a coordinating role in recent
recovery efforts by working with users of the Illinois
River, including commercial interests,
non-governmental organizations, and local, state, and federal
government agencies, to develop a comprehensive
(Illinois River Strategy Team, 1997;
. In addition, the Conservancy
developed site conservation plans and demonstration
projects in tributary watersheds
(Lemke et al., 2010;
Lemke et al., 2011)
and in the river floodplain that
includes the Emiquon Floodplain Restoration Project
, which is the focus of this Special Issue.
After a decade of restoration at the Emiquon
Preserve, considerable progress has been made toward
the primary objective of the project to restore the
natural hydrology and ecological processes that
sustain the aquatic and terrestrial communities associated
with the river–floodplain system. Additional goals
included flood attenuation, sediment capture, nutrient
processing, and improved governance for coordinated
management of the system
(TNC, 1998, 2000)
would provide ecological, social, and economic
benefits within the Illinois River system and would
contribute to better resource quality for the Mississippi
River (Reuter et al., 2005).
Several additional aspects of the Emiquon
Preserve restoration case study are noteworthy. First,
there was a coordinated planning process prior to
restoration among external experts and stakeholders
that resulted in a guidance framework to assess
restoration status over the early restoration period
(Lemke et al., 2017a, b, c, d)
. Secondly, the
restoration and monitoring were designed to
contribute to better documentation of the feasibility and
sustainability of ecological restoration in highly
altered floodplain–river systems
(Suding et al,
2004; Choi et al., 2008; Hobbs & Cramer, 2008;
Jackson & Pringle, 2010)
. In this Special Issue, we
offer a perspective that we hope will contribute to
restoration and conservation programs of large river
ecosystems worldwide by providing (1) an overview
of the scientific and historical context of the river and
region; (2) a description of restoration progress at the
Emiquon Preserve; and (3) an overview of the
significance this collection of studies has for large
river restoration ecology.
Part 1: The Scientific and Historical Context of the Illinois River and Region
The complex history of change to the Illinois River can
be summarized with key events in science and
management (Fig. 1) within the context of three
descriptive periods: (1) minor human disturbance,
(2) human development and major impacts, and (3)
recovery and restoration.
Period 1 (prehistoric-1900): Period of minor
The Illinois River begins at the junction of the
Kankakee and Des Plaines rivers in northern Illinois,
and drains 73,038 km2 as it flows 439 km to the
. Its broad floodplain
and seasonal flood pulse lent it similar qualities to
large lowland rivers of the world and supported
prehistoric populations of Native Americans primarily
between 800 and 1400 A.D.
(e.g., harvesting of natural resources for tools, food,
fuel, and construction; gardening and farming; and
intentional burning of prairies and some woodlands) of
these early civilizations on the river system were not
thought to be extensive based on archeological records
that document their activities
(Wiant & Berkson,
There were about 40,000 people in the southern part
of Illinois in 1800 when it became a state
; yet by 1840, about 190,000 people inhabited
the Illinois River Basin south of Chicago
. A canal, completed in 1848 and used until
1910, connected the south-flowing Illinois River to
Lake Michigan and apparently had little effect on river
ecology as indicated by thriving mussel populations
(Calkins, 1874; Starrett, 1971)
During that time, the science of ecology was
founded and several important ecological studies on
the Illinois River laid the foundation of the aquatic
. While serving as
State Entomologist of Illinois and Professor of
Zoology and Entomology at Illinois State University,
Stephen A. Forbes delivered a talk to the 1887 meeting
of the Peoria Scientific Association entitled ‘‘The Lake
as a Microcosm’’ that was later published
and widely cited as a classic paper in ecology
(Real & Brown, 1991)
. Forbes explained how Illinois
lakes were either watershed lakes or ‘‘fluviatile
lakes… situated in the river bottoms and connected
with the adjacent streams by periodical overflows,’’
and the importance of these lakes as ‘‘reservoirs of
life.’’ Forbes was named director of the State
Laboratory of Natural History in 1877 and became the first
chief of the INHS in 1917
(Havera & Roat, 2003)
marking a period of nearly unprecedented study of the
river. Scientific studies of riverine backwater habitats,
which included Thompson and Flag Lakes of the
present-day Emiquon Preserve (Fig. 2), described
changes in hydrology, plankton
Kofoid, 1903, 1908)
, mussels (Baker, 1906), aquatic
, fishes, and fish production
1889; Forbes and Richardson, 1908)
. These studies
documented the Illinois River and its floodplain as a
high-functioning and largely intact system
Period 2 (1901–1971): Human development
and major impacts to the Illinois River
Pioneering research that focused on the more natural
river system shifted to studies of a river under
development and impacted by changing land uses.
Construction of the Chicago Sanitary and Ship Canal
was the largest earth-moving operation in North
America in the early twentieth century, designed to
divert polluted water away from Chicago’s drinking
water sources in Lake Michigan into the Illinois River
(Hill, 2000, p. 127)
. It opened in 1900 reversing the
flow of the South Branch of the Chicago River from
north into Lake Michigan to flowing south ultimately
into the Illinois River, transporting raw sewage and
storm water away from Chicago
Changnon & Changnon, 1996)
. Pollution in the upper reach
resulted in extirpation of all mussels by 1912
and fishes by the late 1920s
. Pollution advanced downstream
into the lower reaches of the river resulting in the loss of
some invertebrate species
replacement of clean water species (e.g., mayflies and a
variety of snails) with pollution-tolerant forms (e.g.,
tubificid worms and midge larvae).
Water diversion from Lake Michigan increased the
average base water levels in the Illinois by 0.9 m near
Emiquon from 1900 to 1909
(Forbes & Richardson,
. Initially, higher water levels increased aquatic
habitat, but what appeared as an advantage soon
contributed to long-term degradation
(Bellrose et al.,
. Expanded water surface areas increased wind
fetch and wave action that eroded shorelines, uprooted
aquatic plants, and suspended soft fluvial sediments
(Sparks et al., 1990)
. Water-intolerant tree species
perished essentially removing windbreaks on islands
and along the river banks. Water diversion from Lake
Michigan was eventually reduced by decrees from the
U.S. Supreme Court, yet base-flow water levels in the
river remained elevated from pre-development levels
as a series of mainstem dams were completed in the
1930s to maintain depth for navigation
. These dams permanently elevated low water
levels upriver of the dams that depleted the river
system of the natural low water stages
(Lian et al.,
, thereby compromising such ecosystem services
as sediment compaction, moist soil revegetation, and
From 1890 to 1924, widespread levee construction
and drainage of river floodplain habitats
contributed to a channelized river mainstem,
reduced flood pulses to the floodplain, and nearly half
of the floodplain, including Thompson and Flag Lakes,
being converted to agricultural production
et al., 2003; Fig. 3)
. Jenkins et al. (1950) reported that
levee construction resulted in flood crests three meters
higher in 1943 than occurred during pre-construction
floods of 1904.
Subsoil drainage associated with agriculture and
channelization of the tributaries increased erosion and
accelerated the delivery of water and sediment to the
river. Sedimentation rates were as high as 78 mm/year
in floodplain lakes that were still connected to the
river, resulting in a loss of approximately 75% of
backwater lake volume by the late twentieth century
(Bhowmik & Demissie, 1989; Demissie et al., 1992)
Loss of hydraulic storage, in conjunction with
increased frequencies of high-precipitation events,
and enhanced drainage from the watershed
(Jha et al.,
2004; Tomer & Schilling, 2009; Kunkel et al., 2013)
contributed to increased flood events and an erratic
river hydrograph (Figs. 4A, B). Such hydrologic
changes lie at the heart of large river ecosystem
Large floods in 1943 and 1944 reduced vegetation
and dispersed sediments to the river mainstem and
floodplain lakes. Pollution in the upper river created
and perpetuated an area devoid of aquatic life. The
lakes and backwaters of the middle river that
had described as aquatic gardens early in the
century had become turbid, plantless ‘‘deserts’’ by the
(Bellrose et al., 1979)
. Loss of the
onceabundant fingernail clams (Sphaeriidae), snails
(Gastropoda), and burrowing mayflies (Hexagenia spp.)
led to a decline of fish and waterfowl populations
(Mills et al., 1966)
. Subsequent sediment bioassays
revealed that toxic, unionized ammonia in the
nitrogen-enriched sediments may have caused the original
die-offs of burrowing macroinvertebrates and
accounted for their failure to recolonize
et al., 1993)
. Similarly, reduced commercial fish body
conditions were recorded as fish harvests declined and
diving ducks virtually stopped using the Illinois River
as a migration route
(Mills et al., 1966)
Period 3 (1972–present): Recovery
The passage of the Clean Water Act in 1972 signaled
the beginning of improved water quality owing to
upgraded wastewater treatment methods. Even so, it
would take decades for fish
(Lerczak & Sparks, 1995;
Pegg & McClelland, 2004)
et al., 2001)
to recover. The twentieth century closed
with an articulation of a significant river ecology
theory that incorporated flood pulse patterns observed
from the Illinois River: the ‘‘Flood pulse Concept’’
(Junk et al., 1989)
and ‘‘The Flood pulse Advantage’’
emphasized the importance of the
flood pulse in large river ecology and how it is
essential for high system-level biological productivity.
By 1992, the Illinois River system was designated
as having high potential for restoring ecosystem
function of the river and its floodplain
Research Council, 1992; Upper Mississippi River
Conservation Committee, 2000; U.S. Army Corps of
. These assessments for restoration
were based on the facts that the Illinois River had low
navigation dams and that over 50% of the floodplain
remained unleveed. Initiation of habitat and
floodplain restoration of the river system would need to
take into consideration all of the system-level
impacts that contributed to degradation of the system
over time. These impacts included (1) leveed
floodplains, (2) agriculture and urbanization, (3) increased
flood flashiness, (4) increased river flows from
diversion, (5) unnaturally high river water levels,
(6) invasive species, and (7) high loads of sediment,
contaminants, and nutrients
(Jackson & Pringle,
2010; Guida et al., 2016; Sparks et al., 2016; Lemke
et al. 2017a)
. The story of the Emiquon Preserve
began in 2000.
Part 2: Acquisition, planning, and restoration of the Emiquon preserve: large-scale restoration ecology comes to the Illinois river
Opportunity, need, and providence can work in
concert to bring about change, and such was the case
in the area north of the confluence of the Illinois and
Spoon Rivers today known as the Emiquon Preserve
(Fig. 2). The relevant aspects of the Emiquon
Preserve’s restoration to this Special Issue include the
role of science in restoration and the Conservancy’s
approach to management. Given that restoration
requires planning and long-term commitments, a brief
description of future plans is also described.
B Hydrograph of the Illinois River near present-day Emiquon
Preserve, depicting late-nineteenth-century flood pulse (spring
flood, low and stable summer water levels; blue line), erratic
present day fluctuations (purple line), and water level within the
Emiquon Preserve (brown line)
Acquisition and partnerships The Emiquon Preserve was established in 2000 when the Conservancy acquired most of the Thompson Drainage and Levee District (Fulton County, IL;
centroid at: N4471044, E749023 UTM Z15). Over
90% of the 2,723-ha Emiquon Preserve is in the
floodplain west of the river. Immediately adjacent are
the 1,052-ha Emiquon National Wildlife Refuge and
1,817-ha Chautauqua National Wildlife Refuge. The
Emiquon complex, comprising the Emiquon Preserve
and the U.S. Fish and Wildlife Service’s Emiquon and
Chautauqua National Wildlife Refuges, was
recognized in 2012 as a Ramsar Wetland of International
. Together, these three
properties create a 5,592-ha complex of rivers,
sloughs, flood-pulsed backwater areas, bottomland
hardwood forests, prairies, and bluffs that closely
represent the historical diversity of the area and
establish an 8.5-km-wide corridor across the
floodplain and extends 13.5 km in length downstream.
Scientific studies of the Illinois River system
continue to play a significant role in planning and
documenting the outcome of restoration at the
Emiquon Preserve. Over 180 scientific research
permits were issued by the Conservancy between
2007 and 2016. Nearby facilities each serve a role in
the scientific contribution to restoration and
management efforts and include (1) INHS Forbes
Biological Station whose specific focus is on the ecology
and management of wetlands, waterfowl, and other
waterbirds; (2) INHS Illinois River Biological
Station, which is part of the Long Term Resource
Monitoring element of the UMRRP, and whose
monitoring includes fish, vegetation, and invasive
species; (3) Illinois State Museum at Dickson
Mounds, an on-site museum whose ongoing
archeological research and displays document how the
abundant natural resources of the Illinois River and
its floodplains have supported human communities
for at least 12,000 years
(Wiant & Berkson, 2004)
and (4) University of Illinois Springfield Therkildsen
Field Station that supports education and exploration
of the Emiquon Preserve and has been instrumental in
orchestrating science information exchange through
annual science meetings since 2007 (Fig. 2).
In 2001 and 2004, the Conservancy convened a
50-member Emiquon Science Advisory Council
(hereafter, Council) of scientists, resource managers,
and private wetland restoration practitioners to assist
in development of a plan for restoration and long-term
management. The Council emphasized the importance
of natural variation in the hydrologic regime and
periodic connections between rivers and their
floodplains to maintain biological productivity and
diversity. The Council also recognized the potential
negative effects of reconnecting to a highly altered
system with an elevated hydrograph
(e.g., Jackson &
The Council advised simulation models be
developed for alternative reconnection scenarios between
the river and Preserve. These models showed that
hydrologic variation associated with reconnection
could be beneficial and that reconnection would need
to be managed to limit deleterious effects
et al., 2005)
. Using a water control structure and
pumps, a flood regime could be established to provide
drawdown and sediment compaction periods that
would have periodically occurred in Thompson and
Flag Lakes prior to disconnection from the Illinois
(Bellrose et al., 1979; Havera & Roat, 2003)
Alternating seasonally timed periods of drawdown
with flood events could enhance the establishment of
desirable plant and animal communities
(van der Valk
& Davis, 1978)
and help manage sediment deposition
to maintain water depths and water quality
Among the myriad of considerations that go into a
long-term, large-scale restoration, hydrology, biota,
and outreach to stakeholders are aspects that were
prominent in the Emiquon restoration and are relevant
to other large river restoration efforts. Site hydrology
of the Emiquon Preserve changed when ecological
restoration began in 2007. Drainage of the site through
water pumping was discontinued and water levels rose
primarily due to direct precipitation. In 2008 and 2009,
exceptionally heavy rainfall rapidly increased water
volume and surface area within the Preserve
2010; Fig. 4B)
to the point that the separate lake
basins of Thompson and Flag Lakes formed a single
2,000-ha water body. Except for limited pumping in
2008 and 2010 and brief periods of river water
inundation during flood events in 2013, 2015, and
2016, water levels have been stable since 2010.
Evaporation during a moderate summer drought in
2012 resulted in a 0.6-m drop in water level that was
followed by a 1.2-m rise
the spring of 2013
levees were over-topped for six days during record
flooding on the Illinois River. By contrast, the level of
the Illinois River varied more than 7 m during this
same time (USACOE River Gages.com—Havana
gage), and the historic hydrograph suggests that
prealteration river levels rose and fell 3.0–4.5 m from the
average spring peak to the average summer low level
(Fig. 4B). Construction of a water management
system was completed in 2016 and consists of two 4.6-m2
gates and two 1.9-m3/s pumps that will allow
controlled movement of water between the Emiquon
Preserve and the Illinois River (Fig. 5A, B).
Restoration of the biological communities was
accomplished by plantings, fish stocking, natural
regeneration, and recolonization. While aquatic
vegetation was allowed to re-establish from existing seed
banks, dispersion from drainage ditches, or by seed
dispersal, tallgrass prairie areas were established by
seeding and bottomland forest through the planting of
about 180,000 sapling trees of 10 hardwood species.
More than 1,800 ha of row-crop fields with deep
ditches and subsurface drain tiles were transformed
into marsh and shallow lake habitats with submerged
and floating-leaf aquatic vegetation, persistent
emergent vegetation, and open water
(Hine et al., 2014)
establish the fish community, the Illinois Department
of Natural Resources and the Conservancy developed
a cooperative fisheries management agreement for the
Emiquon Preserve. Existing fish populations in the
drainage ditches (e.g., common carp; Cyprinus carpio)
were drastically reduced, then stocking of about
435,000 young-of-year and adults of 31 native species,
and 1.2 million larval largemouth bass
salmoides; VanMiddlesworth et al., 2014)
Outreach and public use of the Emiquon Preserve
are also key elements of the restoration project. A
public visitor use area with educational and
interpretive facilities was constructed by the Conservancy. In
addition, public access for canoeing, bird watching,
hunting, and fishing is allowed resulting in 27,000
visitors in 2015 (about 1600 permits for boating and
fishing, 450 hunting permits, and 1600 people
attending programs and tours).
Significant strides toward achieving the Preserve’s
goals can be observed by the return of species richness
and abundance comparable to historical references.
However, success for lentic aquatic systems in a
prairie landscape may be short lived without the
dynamic, flood-pulsed river hydrology as the driving
mechanism for large river restoration. Restoration
ecology theory forecasts that the future is far from
apparent even in systems simpler than those driven by
disturbances, including flooding. For instance,
explains several possible restoration
trajectories that may diverge from targeted outcomes and
Matthews and Spyreas (2010)
trajectories of restored wetlands diverged toward different
higher-integrity states, but over longer periods
converged on degraded states.
Three potential future conditions for the Emiquon
Preserve have analogs within the Illinois River
system: reservoirs, moist soil management areas,
and extant backwaters with unmanaged connectivity
with the river. If the Emiquon Preserve were to be
kept in isolation with a relatively flat hydrograph, the
wetland is likely to degrade
(van der Valk & Davis,
1978; Hine et al., 2016)
and take on the function and
composition of a reservoir similar to sites managed
for sport fisheries. This management model would
provide little or no persistent emergent, hemi-marsh,
or submersed aquatic-floating-leafed vegetation
habitats that benefit native fishes and other floodplain
biota. A second scenario seen at regional sites
isolated from the river is the complete or nearly
complete annual summer drawdown of water for
moist soil plant production to provide habitat for
(e.g., Bowyer et al., 2005;
Stafford et al., 2010)
. Managing for moist soil areas
helps simulate the advantages of a changing
hydrograph. However, without hydrologic connectivity,
these sites would contribute little to the aquatic
productivity and diversity of the river ecosystem. The
third option for future conditions listed here would be
to simply open the levees to the river and create an
unmanaged connection to Emiquon. In this scenario,
the Preserve would eventually take on the
characteristics of other extant connected backwater lakes that
have become loaded with flocculent sediment, fail to
support rooted aquatic vegetation, and are dominated
by non-native fishes. Sedimentation rates would be
relatively slow because of the large volume of
Emiquon in relation to the openings, which would
most likely be relatively small initially because of the
cost of excavation (Demissie et al., 1992).
The Conservancy’s working hypothesis for the
Emiquon restoration is that a managed reconnection
will facilitate the reestablishment of a dynamic
hydrology that mimics the historic flood pulse (Reuter
Fig. 5 A Emiquon Preserve (right) and Illinois River (left) on
October 19, 2016. Clear water was being discharged from
Emiquon into the Illinois River. Anglers in two boats are fishing
in the discharge. The former agricultural drainage ditch, lined
with trees and shrubs, extends into the distance at the right
(Photo: D. Blodgett). B Looking from the Illinois River toward
the gate structure in the Emiquon levee. The yellow crane on top
of the structure is used to lift nets, other sampling devices,
screens, and metal stop ‘‘logs’’ in and out of the gates. Stop logs
et al., 2005). The importance of the timing, magnitude,
and duration of the river flood pulse to the ecology of
the river system cannot be overstated; it is perhaps the
most important driver of high biological diversity even
to the point of controlling invasive species. Thus, by
managing the timing, direction, and quantity of water
movement between the Preserve and the Illinois River,
diversity and integrity of the vegetation communities
are in place in the gate on the right, and screen is in place in the
left gate, which is discharging water from Emiquon into the
Illinois River. On top of the structure are two frames with
underwater speakers that are used to test the effectiveness of
sound in repelling Asian carps. The structure on top of the levee
behind the white van houses data loggers. A mast with
meteorological sensors is to the right of the instrument house
(Photo: R. Sparks)
will be maintained. Supporting a diverse natural flora
should help suppress invasive species through biotic
resistance, though active control will likely be
necessary periodically. A controlled river connection can
allow water to pass to and from the Preserve at
opportune times for river water height, yet when
sediment load is lower, thus limiting sediment
deposition (Fig. 5A, B).
Part 3: Scientific perspectives of the large-scale floodplain restoration in the Illinois river valley
This special issue for Hydrobiologia is a collection of
papers authored by the scientists and managers who
have been studying the Emiquon Preserve restoration
project since its inception. It represents work that
paints a comprehensive scientific picture of restoration
with an emphasis in this issue on shallow lakes and
their associated wetland habitat along the Illinois
Incorporating the insights of the Council with a
framework developed by
Parrish et al. (2003)
Conservancy identified conservation targets for the
Emiquon Preserve restoration. These targets were
framed by key ecological attributes (KEAs) with
measurable indicators used to assess ecosystem status
(TNC, 2006). In this issue, Lemke et al. (2017a, b, c, d)
report how the application of the KEA framework
during the initial eight years of restoration directed a
systematic monitoring program that provided annual
data on the status of conservation targets. Continued
review and modification of the KEA model in
conjunction with strategic monitoring and a managed
reconnection to the river will provide relevant
information to guide future management decisions and
testable hypotheses to reduce potential threats and
achieve restoration goals.
A range of ecological responses to restoration have
been closely monitored that include microorganisms
(Lemke et al., 2017b)
(Hine et al., 2016)
fish (Van Middlesworth et al., 2016a, b), and
(Hagy et al., 2016a, b)
, making the Emiquon
Preserve among the most intensively studied
floodplain restorations in the world.
Lemke et al. (2017b) recognized that large river
system conditions may change rapidly, and
characterized microbial communities whose member
populations consist of a mix of rapid and slow responders.
Even in the first full year of restoration in 2008,
bacterioplankton, protozoans, phytoplankton, and
zooplankton showed seasonal changes that were very
different in Thompson Lake than those in a nearby
reference lake (Lake Chautauqua). Bacteria,
phytoplankton, and zooplankton in the newly restored lake
appeared to respond quickly to events such as nutrient
surges and cyanobacterial blooms, whereas ciliate
richness and abundances showed less change through
time indicating more of a buffered response between
nutrients and predation. Indicator taxa mapped by
Lemke et al. (2017b) serve as a reference for
subsequent restoration efforts.
Unlike many floodplain lakes along the Illinois
River, Thompson and Flag Lakes had rapid wetland
vegetation response because the lakes were devoid of
significant sedimentation and maintained moderate
(Hine et al., 2016)
. Hine et al. (2016)
report that natural regeneration accounted for an
eightfold expansion of vegetation from 2007 to 2013
and that the dominant vegetation in the wetland habitat
consisted of floating-leaved and submersed aquatic
vegetation (about 44%) and persistent emergent
vegetation (21%), habitat types historically abundant
in Illinois River backwater lakes yet largely absent
from contemporary backwater lakes.
Fish communities also responded positively to
reflooding of the Emiquon Preserve lake basins
(VanMiddlesworth et al., 2016a)
. Fish species richness
increased the first five years of restoration at the
Emiquon Preserve and approximately 66% of the
original 32 species that were stocked in 2008 were
collected during monitoring. Inability to collect the
remaining 33% could have been due to many factors,
including the sequence in which species were
introduced to the growing assemblage, small number of
individuals stocked for many species, and
intentionally high stocking of piscivorous fishes. Van
Middlesworth et al. (2016a) addressed the feasibility of
biomanipulation to suppress invasive species by
increasing largemouth bass predation.
VanMiddlesworth et al. (2016b) explored the diets of several
piscivorous fishes at the Emiquon Preserve and did not
find direct evidence of largemouth bass, bowfin (Amia
calva), or spotted gar (Lepisosteus oculatus) preying
on common carp. However, it did seem possible from
their findings that a diverse assemblage of predatory
fishes reduces the number of carp eggs and may induce
repression of common carp.
As one of the major tributaries to the Mississippi
River, the Illinois River is part of the world-renowned
waterfowl migration routes through the Mississippi
River flyway. Hagy et al. (2016a) documented the
tremendous response of waterbirds to wetland
restoration at Emiquon showing that about 30% of all
waterbird use-days observed during autumn migration
in the Illinois River valley between 2007 and 2013
occurred at Emiquon, even though the Preserve only
represented about 5% of the flooded area in the valley.
Among the most noteworthy responses at Emiquon
were the American coots, northern pintail (Anas
acuta), and green-winged teal (Anas carolinensis),
which exhibited the greatest use recorded for any site
in the Illinois River Valley since 1948. In a second
study by Hagy et al. (2016b), the distribution and
behavior of migratory waterbirds across a gradient of
disturbance was measured to evaluate the efficacy of
spatial and temporal sanctuaries. For the taxa
evaluated, zones of exclusion of waterbirds near human
disturbances were the smallest in areas least frequently
visited by hunters and other users, and exclusion zones
were larger in areas most frequently visited.
Nonetheless, the investigators questioned the effectiveness of
short-term temporal sanctuaries compared to spatial
sanctuaries, contending that even few and infrequent
disturbances substantially reduce sanctuary
conditions, and that continual immigration of migratory
birds through the area resulted in naive responses,
reducing the potential benefits of temporal sanctuaries.
All the studies provided here fit into the greater
system; however, some studies focused on ecosystem
Chen et al. (2017)
considered that whereas
wetland conversion to cropland causes significant
release of soil organic matter to atmospheric carbon
dioxide, wetland restoration may sequester vast
quantities of carbon. They determined that the top 40 cm of
soil held 88% of carbon storage and 97% of total
nitrogen storage as organic matter.
Chen et al. (2017)
make a compelling case for comparing soil organic
carbon to other key ecological attributes and indicators
being monitored, and for establishing storage of soil
organic carbon as an indicator of restoration success.
Lemke et al. (2017c) took the opportunity provided
by record flooding on
the Illinois River in 2013
study post-flood effects on the Emiquon Preserve and
the Merwin Preserve, a Conservancy holding along the
Illinois River that was under restoration a decade
before Emiquon. While connection of the river flood
pulse to the floodplain is understood to be among the
most important factors defining the river system, the
design, operation, costs, and benefits of the
river-tofloodplain connection in the twenty-first century are
not clear cut. Concerns about the effectiveness of the
managed reconnection between the Emiquon Preserve
and the Illinois River center around unnatural
sediment and nutrient loading, influx of agro-chemicals,
and invasive species. The investigators monitored the
short-term effects of these minor (Emiquon) and major
(Merwin) flood disturbances on water quality,
bacteria, zooplankton, plants, fishes, and birds and found
that major flooding markedly changed the microbial
and invertebrate communities at the Merwin Preserve,
while few significant changes were identified from
Sparks et al. (2016)
considered the Emiquon of
today along with the potential to understand
restoration in the future. A debate about a managed
connection between the Preserve and the Illinois River began
soon after the Conservancy announced the acquisition
in 2000 and continued until construction began in
2015. There is consensus among contributed papers to
this Special Issue that some drawdown capability is
needed to manage and reduce water levels within
Emiquon Preserve to protect and maintain
infrastructure and encourage aquatic vegetation. At the heart of
the debate is whether river water carrying sediment,
contaminants, nutrients, and invasive species will
contribute to unacceptable degradation of the wetland.
The water management system, completed in 2016, is
a gated structure with pumping capacity that can
accommodate fish barriers and sampling devices
(Fig. 5A, B). Ultimately, the infrastructure is intended
to support both scientific research that benefits other
projects as well as adaptive management of the
(Sparks, 1995; Reuter et al., 2005;
King et al., 2010)
Human societies worldwide have altered large
rivers and their floodplains for survival
1985; Bayley, 1995)
often with the consequence of
greatly diminishing the same ecological processes that
have made these systems valuable to societies for
(Dynesius & Nilsson, 1994; Sparks, 1995;
Tockner & Stanford, 2002)
. Thus, large-scale projects
are being undertaken in many parts of the world to
recover natural services while also maintaining
commercial uses such as navigation and water supply
(Bernhardt et al., 2007; Lamouroux et al., 2015)
Studies of the Emiquon Preserve as part of the Illinois
River system make a significant contribution to
understanding large river floodplain restoration in
the central United States region, and have implications
for restoration in critically threatened river ecosystems
throughout the world.
Acknowledgements We thank The Nature Conservancy’s S.
McClure and S. Hagen for assistance with figures, and J.
Beverlin and C. Smith for visitor use information. The major
research partners at Emiquon include the Illinois Natural
History Survey’s Forbes Biological Station and Illinois River
Biological Field Station and the University of Illinois
Springfield. We also thank M. Wiant of the Illinois State
Museum for contributing insights on the human ecology at
Emiquon. We gratefully acknowledge the important roles of the
Natural Resources Conservation Service, Illinois Department of
Natural Resources, U.S. Army Corps of Engineers, and US Fish
and Wildlife Service in planning, restoring, and managing the
Open Access This article is distributed under the terms of the
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Angel , J. , 2010 . Fourth Wettest Year on Record. Illinois State Water Survey . http://www.sws.uiuc.edu/atmos/statecli/ events2009.htm
Baker , F. C. , 1906 . A catalogue of the Mollusca of Illinois . Bulletin of the Illinois State Laboratory of Natural History 7 ( 6 ): 53 - 136 .
Bayley , P. G. , 1991 . The flood pulse advantage and the restoration of river-floodplain systems . Regulated Rivers Research & Management 6 : 75 - 86 .
Bayley , P. B. , 1995 . Understanding large river: floodplain ecosystems . BioScience 45 ( 3 ): 153 - 158 .
Bellrose , F. C. , F. L. Paveglio , Jr. & D. W. Steffeck , 1979 . Waterfowl populations and the changing environment of the Illinois River valley . Illinois Natural History Survey Bulletin 32 : 1 .
Bellrose , F. C. , S. P. Havera , F. L. Paveglio , Jr. & D. W. Steffeck , 1983 . The fate of lakes in the Illinois River Valley . Illinois Natural History Survey Biological Notes 119 .
Bernhardt , E. S. , E. B. Sudduth , M. A. Palmer , J. D. Allan , J. L. Meyer, G. Alexander, J. Follstad-Shah , B. Hassett , R. Jenkinson , R. Lave , J. McFall & L. Pagano , 2007 . Restoring rivers one reach at a time: Results from a survey of U.S. river restoration practitioners . Restoration Ecology . 15 : 482 - 493 .
Bhowmik , N. G. & M. Demissie , 1989 . Sedimentation in the Illinois River valley and backwater lakes . Journal of Hydrology 105 : 187 - 195 .
Bowyer , M. W. , J. D. Stafford , A. P. Yetter , C. S. Hine , M. M. Horath & S. P. Havera , 2005 . Moist-soil plant seed production for waterfowl at Chautauqua National Wildlife Refuge, Illinois . The American Midland Naturalist 154 : 331 - 341 .
Buck , S.J. , 1967 . Illinois in 1818 , by Solon J. Buck . Revised and Reprinted on the Occasion of the Sesquicentennial of the State of Illinois; with an Introduction by Allan Nevins . University of Illinois Press, 1967 .
Cain , L. P. , 1978 . Sanitation Strategy for a Lakefront Metropolis . Northern Illinois University Press, DeKa1b, IL.
Calkins , W. W. , 1874 . The land & fresh water shells of La Salle County , Illinois. Ottawa Academy of Natural Sciences Proceedings. 48 p.
Changnon , S. A. & J. M. Changnon , 1996 . History of the Chicago diversion and future implications . Journal of Great Lakes Research 22 : 100 - 118 .
Chen , H., S. Popovich , A. B. McEuen & B. J. Briddell , 2017 . Carbon and nitrogen storage of a restored wetland at Illinois' Emiquon preserve: potential for carbon sequestration . Hydrobiologia. doi:10 .1007/s10750-017-3218-z.
Choi , Y. D. , V. M. Temperton , E. B. Allen , A. P. Grootjans , M. Halassy , et al., 2008 . Ecological restoration for future sustainability in a changing environment . Ecoscience 15 : 53 - 64 .
Cocker , R. A. , 2001 . Stephen Forbes and the Rise of American Ecology . Smithsonian Institution Press, Washington D.C: 232 .
Craig , W. , 1889 . On the fishes of the Illinois River system at Havana, Illinois . MS Thesis . University of Illinois, Urbana.
Demissie , M. , L. Keefer & R. Xia , 1992 . Erosion and sedimentation in the Illinois River Basin. Illinois Department of Energy and Natural Resources , ILENR/RE-WR- 92 /04. Springfield, IL.
Demissie , M. , A. Wehrmann , Y. Lian , G. Amenu, S. Burch , & W. Bogner, 2005 . Hydrologic and hydraulic considerations for the ecological restoration of the Emiquon along the Illinois River . Proceedings World Water & Environmental Resources Congress, May 15-19 , 2005 , Anchorage, AK. American Society of Civil Engineers, Reston, VA
Dynesius , M. & N. Nilsson , 1994 . Fragmentation and flow regulation of river systems in the northern third of the world . Science 266 : 753 - 762 .
Esarey , D. , 1993 (revised 1995 ). The origin and early history of Emiquon . Dickson Mounds Museum, Lewistown, IL.
Forbes , S. A. , 1876 . List of Illinois crustacea, with descriptions of new species . Illinois Natural History Survey Bulletin l: 3 - 25 .
Forbes , S. A. , 1887 . The Lake as a Microcosm . Bulletin of the Peoria Scientific Association 1887 : 77 - 87 .
Forbes , S. A. , 1888 . On the food relations of fresh-water fishes: a summary and discussion . Illinois Natural History Survey Bulletin 2 : 475 - 538 .
Forbes , S. A. , 1907 . On the local distribution of certain Illinois fishes: an essay in statistical ecology . Illinois Natural History Survey Bulletin 7 : 273 - 303 .
Forbes , S. A. & R. E. Richardson , 1908 . Fishes of Illinois. Illinois Printing Company, Danville, IL.
Forbes , S. A. & R. E. Richardson , 1913 . Studies on the biology of the upper Illinois River . Bulletin of the Illinois State Laboratory of Natural History 9 : 481 - 574 .
Forbes , S. A. & R. E. Richardson , 1919 . Some recent changes in Illinois River biology . Illinois Natural History Survey Bulletin 9 : 481 - 574 .
Guida , R. J. , J. W. F. Remo & S. Secchi, 2016 . Tradeoffs of strategically reconnecting rivers to their floodplains: the case of the Lower Illinois River . Science of the Total Environment 572 : 43 - 55 .
Hagy , H. M. , C. Hine , M. Horath , A. Yetter , R. Smith & J. Stafford , 2016a. Waterbirds as indicators of floodplain restoration . Hydrobiologia. doi:10.1007/s10750-016- 3004-3.
Hagy , H. M. , M. M. Horath , A. P. Yetter , C. S. Hine & R. V. Smith , 2016b . Evaluating tradeoffs between sanctuary for migrating waterbirds and recreational opportunities in a restored wetland complex . Hydrobiologia. doi:10.1007/ s10750-016-2711-0.
Hart , C. A. , 1896 . On the entomology of the Illinois River and adjacent waters . Bulletin of the Illinois State Laboratory of Natural History 4 ( 6 ): 1 - 273 .
Havera , S. P. , & K. E. Roat , 2003 . Forbes Biological Station: the past and the promise . Illinois Natural History Survey Special Publication 10
Havera , S. P. , K. E. Roat & L. L. Anderson , 2003 . The Thompson Lake/Emiquon Story. Illinois Natural History Survey Special Publication 25 , Champaign , IL.
Hempel , A. , 1898 . A list of the protozoa and Rotifera found in the Illinois River and adjacent lakes at Havana, Illinois . Bulletin of the Illinois State Laboratory of Natural History 5 ( 6 ): 301 - 388 .
Hill , L. , 2000 . The Chicago River: A Natural and Unnatural History . Lake Claremont Press, Chicago, IL.
Hine , C.S. , H.M. Hagy , A.P. Yetter , M.M. Horath , 2014 . Waterbird and wetland monitoring at the Emiquon Preserve: annual report 2013. Illinois Natural History Survey Technical Report (18).
Hine , C. S. , H. M. Hagy , M. M. Horath , A. P. Yetter , R. V. Smith & J. D. Stafford , 2016 . Response of aquatic vegetation communities and other wetland cover types to floodplain restoration at Emiquon Preserve . Hydrobiologia. doi:10. 1007/s10750-016-2893-5.
Hobbs , R. J. & V. A. Cramer , 2008 . Restoration ecology: Interventionist approaches for restoring and maintaining ecosystem function in the face of rapid environmental change . Annual Review of Environment and Resources 33 : 39 - 61 .
Illinois River Strategy Team , 1997 . Integrated management plan for the Illinois River Watershed . Technical report of the Illinois River Strategy Team. State of Illinois.
Jackson , C. R. & C. M. Pringle , 2010 . Ecological benefits of reduced hydrologic connectivity in intensively developed landscapes . BioScience 60 ( 1 ): 37 - 46 .
Jenkins , Merchant & Nankivil and W.B Walraven . 1950 . Survey and report on potential conservation areas along the Illinois River from Hennepin to Grafton . Illinois Department of Conservation, State of Illinois
Jha , M. , Z. Pan , E. S. Takle & R. Gu , 2004 . Impacts of climate change on streamflow in the Upper Mississippi River Basin: a regional climate model perspective . J. Geophys. Res . 109 : D09105 .
Junk , W. J. , P. B. Bayley and R. E. Sparks . 1989 . The flood pulse concept in river-floodplain systems . In Proceedings of the International Large River Symposium , 106 : 110 - 127 . Canadian Special Publication of Fisheries and Aquatic Sciences.
King , A. J. , K. A. Ward , P. O'Connor , D. Green , Z. Tonkin & J. Mahoney , 2010 . Adaptive management of an environmental watering event to enhance native fish spawning and recruitment . Freshwater Biology 55 : 17 - 31 .
Kofoid , C. A. , 1903 . The plankton of the Illinois River, 1894 - 1899 , with introductory notes upon the hydrography of the Illinois River and its basin. Part I. Quantitative investigations and general results . Bulletin of the Illinois State Laboratory of Natural History 6 ( 2 ): 95 - 629 .
Kofoid , C. A. , 1908 . The plankton of the Illinois River, 1894 - 1899 , with introductory notes upon the hydrography of the Illinois River and its basin. Part II. Constituent organisms and their seasonal distribution . Bulletin of the Illinois Laboratory of Natural History 8 ( 1 ): 1 - 361 .
Kunkel , K. E. , L. E. Stevens , S. E. Stevens , L. Sun , E. Janssen , D. Wuebbles , S. D. Hilber , M. S. Timlin , L. Stoecker , N. E. Westcott , and J. G. Dobson . 2013 . Regional climate trends and scenarios for the U.S. National Climate Assessment. Part 3. Climate of the Midwest . U.S. NOAA Technical Report NESDIS 142-3.
Lamouroux , N. , J. A. Gore , F. Lepori & B. Statzner , 2015 . The ecological restoration of large rivers needs science-based, predictive tools meeting public expectations: an overview of the Rhoˆne project . Freshwater Biology 60 : 1069 - 1084 .
Lemke , A. M. , T. T. Lindenbaum , W. L. Perry , M. E. Herbert , T. H. Tear & J. R. Herkert , 2010 . Effects of outreach on the awareness and adoption of conservation practices by farmers in two agricultural watersheds of the Mackinaw River, Illinois . Journal of Soil and Water Conservation 65 : 304 - 315 .
Lemke , A. M. , K. G. Kirkham , T. T. Lindenbaum, M. E. Herbert , T. H. Tear , W. L. Perry & J. R. Herkert , 2011 . Evaluating agricultural best management practices in tiledrained subwatersheds of the Mackinaw River, Illinois . Journal of Environmental Quality 40 : 1215 - 1228 .
Lemke , A. M. , J. R. Herkert , J. W. Walk & K. D. Blodgett , 2017a. Application of Key Ecological Attributes to assess early restoration of river floodplain habitats: A case study . Hydrobiologia. doi:10.1007/s10750-017-3261-9.
Lemke , M. J. , H. M. Hagy , A. F. Casper and H. Chen , 2017b. Chapter 5. Floodplain Wetland Restoration along the Illinois River . In: Lenhart, C. and P. C. Smiley Jr. (eds). Ecological Restoration in the Midwest: Building on the Legacy.
Lemke , M. J., S. F. Paver , K. Dungey , L. F. M. Velho , A. Kent , L. C. Rodrigues , D. M. Kellerhals & M. Randle , 2017c. Diversity and succession of pelagic microorganism communities in a newly restored Illinois River floodplain lake . Hydrobiologia. doi:10.1007/s10750-017-3327-8.
Lemke , M. J. , H. M. Hagy , K. E. Dungey , A. F. Casper , A. M. Lemke , T. D. VanMiddlesworth & A. Kent , 2017d. Echoes of a flood pulse: Short-term effects of record flooding of the Illinois River on floodplain lakes under restoration . Hydrobiologia. doi:10.1007/s10750-017- 3220-5.
Lerczak , T.V. , and R.E. Sparks , 1995 . Fish populations in the Illinois River . Pages 239-241 in National Biological Service National Status and Trends Report. U.S. Government Printing Office , Washington, D.C.
Lian , Y. , J. K. You , R. E. Sparks & M. Demissie , 2012 . Impact of human activities to hydrologic alterations on the Illinois River . Journal of Hydrologic Engineering . doi: 10 .1061/ (ASCE)HE. 1943 - 5584 . 0000465 .
Matthews , J. W. & G. Spyreas, 2010 . Convergence and divergence in plant community trajectories as a framework for monitoring wetland restoration progress . Journal of Applied Ecology 47 : 1128 - 1136 .
McClelland , M. A. , G. G. Sass , T. R. Cook , K. S. Irons , N. N. Michaels , T. M. O'Hara & C. S. Smith , 2012 . The longterm Illinois River fish population monitoring program . Fisheries . 37 ( 8 ): 340 - 350 . doi: 10 .1080/03632415. 2012 . 704815 .
Mills , H. B. , W. C. Starrett & F. C. Bellrose , 1966 . Man's effect on the fish and wildlife of the Illinois River . Illinois Natural History Survey Biological Notes 57 : 1 - 24 .
National Research Council , 1992 . Restoration of aquatic ecosystems: Science, technology, and public policy . National Academy Press, Washington, D.C.: 552 .
Parrish , J. D. , D. P. Braun & R. S. Unnasch , 2003 . Are we conserving what we say we are? Measuring ecological integrity within protected areas . BioScience 53 : 851 - 860 .
Pegg , M. A. & M. A. McClelland , 2004 . Spatial and temporal patterns in fish communities along the Illinois River . Ecology of Freshwater Fish 13 : 125 - 135 .
Ramsar , 2014 . The list of wetlands of international importance . http://ramsar.rgis.ch/pdf/sitelist.pdf
Real , L. A. & J. H. Brown , 1991 . Foundations of ecology: Classic papers with commentaries . University of Chicago Press, Chicago, IL.
Reuter , M. , K. Lubinski , P. West , D. Blodgett & M. Khoury , 2005 . The Nature Conservancy's approach to conserving and rehabilitating biological diversity in the Upper Mississippi River system . Large Rivers 15 : 549 - 560 .
Richardson , R. E. , 1928 . The bottom fauna of the middle Illinois River, 1913 - 1925 ; its distribution, abundance, valuation, and index valve in the study of stream pollution . Illinois Natural History Survey Bulletin 17 ( 12 ): 387 - 475 .
Scarpino , P.V. , 1985 . Great River: an environmental history of the upper Mississippi, 1890 - 1950 . University of Missouri Press.
Schneider , D. W. , 2000 . Local Knowledge, Environmental Politics, and the Founding of Ecology in the United States: Stephen Forbes and ''The Lake as a Microcosm'' ( 1887 ). Isis. 91 : 681 - 705
Sietman , B. E. , S. D. Whitney , D. E. Kelner , K. D. Blodgett & H. L. Dunn , 2001 . Post-extirpation recovery of the freshwater mussel (Bivalvia: Unionidae) fauna in the upper Illinois River . Journal of Freshwater Ecology 16 ( 2 ): 273 - 281 .
Sparks , R. E. , 1995 . Need for ecological management of large rivers and their floodplains . BioScience 45 ( 3 ): 168 - 182 .
Sparks , R. E. , P. B. Bayley , S. L. Kohler & L. L. Osborne , 1990 . Disturbance and recovery of large floodplain rivers . Environmental Management 14 ( 5 ): 699 - 709 .
Sparks , R. E. , P. E. Ross , & F. S. Dillon , 1993 . Identification of toxic substances in the upper Illinois River . Final Report. Illinois Department of Energy and Natural Resources , Springfield, IL
Sparks , R. E. , K. D. Blodgett , A. F. Casper , H. M. Hagy , M. J. Lemke , L. F. M. Velho , & L. C. Rodrigues , 2016 . Why experiment with success? Opportunities and risks in applying assessment and adaptive management to the Emiquon floodplain restoration project . Hydrobiologia. doi: 10.1007/s10750-016-2785-8.
Stafford , J. D. , M. M. Horath , A. P. Yetter , R. V. Smith , and C. S. Hine , 2010 . Historical and contemporary characteristics and waterfowl use of Illinois River valley wetlands . Wetlands 30 ( 3 ): 565 - 576 .
Starrett , W. C. , 1971 . A Survey of the mussels (Unioncea) of the Illinois River: a polluted stream . Illinois Natural History Survey Bulletin 30 : 265 - 403 .
Starrett , W. C. , 1972 . Man and the Illinois River . Pages 131 - 167 . In R. T. Oglesby, C. A. Carlson , and J. A . McCann, editors. River ecology and Man . Academic Press, New York.
Suding , K. N. , 2011 . Toward an era of restoration in ecology: successes, failures, and opportunities ahead . Annual Review of Ecology, Evolution, and Systematics 42 : 465 - 487 .
Suding , K. N. , K. L. Gross & G. Houseman, 2004 . Alternative states and positive feedbacks in restoration ecology . Trends in Ecology and Evolution 193 : 46 - 53 .
The Nature Conservancy (TNC) , 1998 . Illinois River Site Conservation Plan . The Nature Conservancy of Illinois , Peoria, IL.
The Nature Conservancy (TNC) , 2000 . The past and future of the Illinois River Valley: Emiquon, the opportunity of a lifetime. Prepared by the Great Rivers Area staff of The Nature Conservancy for the Emiquon Science Advisory Council . Peoria, IL
The Nature Conservancy , 2006 . Key Attributes and Indicators for Illinois River Conservation Targets at The Nature Conservancy's Emiquon Preserve. The Nature Conservancy , Peoria, Illinois. www.uis.edu/emiquon/wp-content/ uploads/sites/78/2013/04/KEA_Report_and_Analysis. pdf. Accessed November 7 , 2015 .
Thompson , D. H. , 1928 . The ''knothead'' carp of the Illinois River . Illinois Natural History Survey Bulletin 17 ( 8 ): 285 - 320 .
Thompson , J. , 2002 . Wetlands drainage, river modification, and sectoral conflict in the lower Illinois valley, 1890 - 1930 . Southern Illinois University Press, Carbondale.
Tockner , K. & J. A. Stanford , 2002 . Riverine flood plains: present state and future trends . Environmental Conservation 29 : 308 - 330 .
Tomer , M. D. & K. E. Schilling , 2009 . A simple approach to distinguish land-use and climate-change effects on watershed hydrology . Journal of Hydrology 376 ( 2009 ): 24 - 33 .
Upper Mississippi River Conservation Committee , 2000 . A river that works and a working river . Upper Mississippi River Conservation Committee.
USACE (U.S. Army Corps of Engineers), 2006 . Illinois River Basin restoration comprehensive plan . U.S. Army Corps of Engineers, Rock Island District, Rock Island, Illinois.
USACE (U.S. Army Corps of Engineers), 2016 . Report to congress Upper Mississippi River restoration program . U.S. Army Corps of Engineers, Rock Island District, Rock Island, Illinois.
van der Valk , A. G. & C. B. Davis , 1978 . The role of seed banks in the vegetation dynamics of prairie glacial marshes . Ecology 59 : 322 - 335 .
VanMiddlesworth , T. D., N. N. Michaels & A.F. Casper , 2014 . The Nature Conservancy's Emiquon Preserve Fish and Aquatic Vegetation Monitoring 6-year (2007-2012) Report . INHS Technical Report (01).
VanMiddlesworth , T. D., N. N. McClelland , G. G. Sass , A. F. Casper , T. W. Spier & M. J. Lemke , 2016a. Fish community succession and biomanipulation to control two common aquatic ecosystem stressors during a large-scale floodplain lake restoration . Hydrobiologia. doi:10.1007/ s10750-016-2696-8.
VanMiddlesworth , T. D., G. G. Sass , B. A. Ray , T. W. Spier , J. D. Lyons , N. N. McClelland & A. F. Casper , 2016b. Food habits and relative abundances of native piscivores: implications for controlling common carp . Hydrobiologia. doi:10.1007/s10750-016-2866-8.
Welcomme , R. L. , 1985 . River fisheries . FAO Fisheries Technical Paper 262 : 1 - 330 .
Wiant , M. D. , & A. Berkson , 2004 . The Archaic Period . In Wiant, M. D. & A. Berkson (eds), Discover Illinois Archaeology . Illinois Association for Advancement of Archaeology and the Illinois State Archaeological Survey , Champaign, Illinois: 6 - 7 .