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
Introduction
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
development
(Starrett, 1972; Schneider, 2000)
. Such
extensive historic scientific documentation
(e.g.,
Forbes, 1876, 1888; Hart, 1896; Kofoid, 1903; Forbes,
1907; Forbes & Richardson, 1908)
exists for few other
rivers worldwide
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
Refuges
(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
mussel populations
(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
restoration plan
(Illinois River Strategy Team, 1997;
USACE, 2006)
. 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
(TNC, 1998)
, 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 ecolo (...truncated)