Application of key ecological attributes to assess early restoration of river floodplain habitats: a case study
Application of key ecological attributes to assess early restoration of river floodplain habitats: a case study
0 J. R. Herkert Illinois Audubon Society , 2315 Clear Lake Avenue, Springfield, IL 62703 , USA
1 A. M. Lemke (&) K. D. Blodgett The Nature Conservancy , 11304 N Prairie Road, Lewistown, IL 61542 , USA
2 Guest editors: Michael J. Lemke, A. Maria Lemke & Jeffery W. Walk / Large-Scale Floodplain Restoration in the Illinois River Valley , USA
3 J. W. Walk The Nature Conservancy , 240 SW Jefferson St., Suite 301, Peoria, IL 61602 , USA
The Nature Conservancy acquired the Emiquon Preserve along the Illinois River, Illinois, with the primary objective of restoring ecological floodplain processes and habitats that promote and sustain native species and communities. The Conservancy convened an Emiquon Science Advisory Council prior to restoration implementation that identified key ecological attributes (KEAs) for riverine and backwater targets, KEA indicators, and acceptable ranges for those indicators. We assessed the application of this methodology to evaluate status of conservation targets and to inform future science and management at Emiquon. The KEA framework provided an important function of directing a systematic monitoring program that provided fundamental data on changing environmental conditions that were incorporated into annual target evaluations. Data show that 46-55% of all indicators were within acceptable ranges prior to reconnection of the preserve with the Illinois River. Recent completion of a water control structure represents a critical intervention that provides potential to improve conservation status of those floodplain and riverine targets that depend on water management and river connectivity. Continued review and modification of the KEA model in conjunction with a strategic monitoring program will provide critical information to guide relevant management decisions and testable hypotheses to reduce potential threats and achieve future restoration goals.
Key ecological attributes; Emiquon preserve; Illinois River; Floodplain restoration; Biological assessment
Introduction
Ecological structure and function of large river
systems are increasingly threatened worldwide as
modifications for utilitarian purposes such as
navigation, hydroelectric power, agricultural production, and
flood control intensify. Fragmentation of river
channels by navigation dams and reduced hydrologic
connectivity between floodplains and the main river
channel due to levees are two primary impacts that
threaten ecological integrity of these working rivers
(e.g., Dynesius & Nilsson, 1994; Gore & Shields,
1995; Lamouroux et al., 2015)
. Hydrologic alteration
and habitat degradation accompanying this
infrastructure are two major drivers that have placed riverine
floodplains among the most globally endangered
ecosystems such that up to 90% of floodplains in
Europe and North America have lost many of their
natural ecological functions
(Sparks, 1995; Tockner &
Stanford, 2002)
. Increased efforts to conserve and
restore floodplain rivers have paralleled a rising global
awareness of the importance of these ecosystems for
biodiversity and the environmental services they
provide.
The Mississippi River watershed in the United
States is the fourth largest in the world, providing
critical habitat that supports incredible biological
diversity for resident and migratory aquatic and
terrestrial species
(Page & Burr, 1991; UMRCC,
2000; Weitzell et al., 2003)
. Although 90% of the
Lower Mississippi River has been leveed and drained
primarily for agricultural production, an estimated
50% of the original floodplain remains hydrologically
connected to the main channel of the Upper
Mississippi River (UMR) and retains seasonal flood-pulsed
events
(Sparks et al., 1998)
. The Illinois River is one of
the major tributaries to the UMR, draining 44% of the
state of Illinois and linking the Great Lakes to the Gulf
of Mexico. Glacial activity and subsequent flood
events created an extensive floodplain in the Illinois
River basin relative to the size of the river channel,
approximately 50% of which remains unleveed from
the main channel
(Sparks, 1995; Mettler-Cherry &
Smith, 2009)
. A study conducted by the National
Research Council (NRC, 1992) recommended the
Upper Mississippi and Illinois rivers as two of the
three large, river–floodplain systems remaining in the
U.S. that were priorities for restoration. Several
successive reports by the UMR Conservation
Committee (2000) and the
U.S. Army Corps of Engineers
(2007
) supported NRC (1992) conclusions regarding
the importance of restoring floodplain function to
ensure the ecological integrity of these river systems.
Development of an operational framework that
coordinates such recommendations with science and
management is integral to comprehensive planning,
implementation, and assessment of restoration
projects
(Rogers, 2006; Roux et al., 2006)
. As such,
frameworks hav (...truncated)