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Riparian Corridor Planning
What is a Riparian Corridor?
Presentation:  Riparian Corridor - Conduits For Conservation (1.7 mb)
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A Critical Landscape Feature
Riparian ecosystems are critical components of the landscape ecosystem, ecosystems incorporating both ecological and cultural values. The function of riparian ecosystems in the landscape is dictated by their role as both a transition zone between the aquatic and terrestrial environments and as a corridor through the landscape. Many independent landscape elements described by the Michgan Natural Features Inventory are contained within Oakland County riparian ecosystems. Consideration of the integrity of riparian ecosystems in community planning can serve to address multiple community planning objectives, such as open space preservation, water resources management, and enhancement of community character.
Riparian Ecosystems In Landscape Ecology
Riparian ecosystems are critical components of landscape ecology. Their ecological function is dictated by their dual structures in the landscape. Riparian ecosystems are both an ecotone between aquatic and terrestrial ecosystems, as well as a corridor connecting landscapes across regions from upland headwaters to lowland delta areas (Malanson, 1996).
Ecotones are important in landscape ecology because they serve as a transition between two distinct ecosystems. These transition zones provide unique habitats where plant communities make a transition and species intermingle. Ecotones are thought to be generators of biodiversity. The riparian ecotone is particularly important in the urban setting because it serves as the transition zone between human land uses and water resources. In this setting, the riparian ecotone serves as a buffer between land and water for deleterious byproducts of urban land use, including stormwater runoff and pollutants.
Corridors are important in landscape ecology because they connect variable landscapes across regions. Corridors have several critical ecological functions (Federal Interagency Team, 1998) as they:
1. provide habitat
2. act as wildlife conduits
3. act as filters and barriers to species movement
4. and act as sinks and sources of wildlife, nutrients, and energy
The discipline of landscape ecology has accepted three fundamental elements which compose the landscape: patches, corridors, and a matrix (Forman and Godron, 1986). Patches are small areas of a particular ecosystem or landscape type surrounded by areas with a different structure. Corridors are linear patches that differ from their surroundings and connect patches. Matrix is the background within with patches and corridors exist. Within the setting of Oakland County, several types of land uses typically dominate each of these component types (Table and Figure 1).
Table 1. Typical Landscape Components Elements in Oakland County
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Patch:
Corridor:
Matrix:
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Remnant woodlots, wetlands, and other natural areas
Riparian ecosystems, rail trails, parkways that connect patches
Urban and suburban landscapes, to a lesser extent agriculture
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Figure 1. Examples of landscape ecological components along the Clinton River corridor in the City of Rochester Hills
Diverse Ecological Communities
The Michigan Natural Features Inventory (MNFI) has described and abstracted 60 distinct natural community types within the State of Michigan. Twenty-nine of these are likely to occur in riparian ecosystems in the State of Michigan. According to MNFI, 12 of those occur in Oakland County (MNFI, 2001). These include:
* Bog
* Coastal plain marsh
* Emergent marsh
* Hardwood-conifer swamp
* Intermittent wetland
* Prairie fen
* Relict conifer swamp
* Southern floodplain forest
* Southern swamp
* Southern wet meadow
* Submergent marsh
* Wet-mesic prairie
More information about these unique ecosystem types can be found at the MNFI website.
Riparian Ecosystem Values
The values of riparian ecosystems make them worthy of consideration in community planning. Riparian areas have ecological, cultural, and economic functional values that contribute to the quality of life of residents of the communities which contain them (Table 2).
Table 2. Sample ecological, cultural, and economic values of riparian ecosystems and their components
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Value
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Ecological
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Cultural
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Economic
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Riparian Ecosystem as a Whole
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Provide biodiversity
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X
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X
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Provide wildlife corridors
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X
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Filter surface runoff pollutants
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X
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X
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X
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Provide recreational opportunities
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X
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X
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| Surface Hydrology (Lakes, Rivers, & Streams) |
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| Provide drinking water |
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X
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X
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| Provide water supply or drainage to wetlands/lakes |
X
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X
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| Provide opportunity for fisheries/angling |
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X
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X
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| Provide stormwater conveyance/ detention/ treatment |
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X
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X
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| Provide fisheries/waterfowl habitat |
X
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X
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X
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| Floodplains & Wetlands (Tilton, 1999) |
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| Provide floral diversity and wildlife habitat |
X
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| Provide fishery and herpetile habitat |
X
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| Provide flood and stormwater storage |
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X
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X
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| Attenuate surface runoff volumes |
X
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X
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X
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| Provide water quality protection |
X
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X
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X
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| Protect shoreline and streambank from erosion |
X
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X
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X
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| Provide aesthetics and recreation |
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X
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X
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| Groundwater Areas |
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| Recharge groundwater aquifers |
X
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X
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X
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| Provide drinking water |
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X
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X
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| Discharge to groundwater-dependent ecosystems, coldwater fisheries |
X
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X
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X
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| River and Stream Valleys |
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Provide scenic vistas
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X
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X
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| Provide unique topography |
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X
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X
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| Represent cultural history |
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X
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X
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Threats to Riparian Corridors in Oakland County
Many threats to riparian corridors exist within Oakland County. These threats result from many sources, including inappropriate development techniques and inappropriate management of the stream or nearby water resources. Threats may impact the ecological, cultural, or economic values of the riparian corridor. Because these values are interdependent, impact on one value often impacts other values.
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Development too close to an unstable bluff along the Clinton River in Rochester Hills has put both the homeowners property and the river at risk.
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Solutions to bank failure such as the gabion armoring shown here along the Paint Creek within the Rochester Municipal Park may cause other problems such as loss of habitat and aesthetics.
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Potential threats to riparian corridors in Oakland County include the following:
* Dams
* Channelization and diversion
* Agriculture and forestry
* Erosion sedimentation
* Streambank failure
* Streambank hardening
* Exotic Invasive Species
* Restricted access
* Destruction of historic sites
* Inappropriate development
* Floodplain separation
* Vegetation removal
* Agriculture and livestock
* Road crossings
* Culverts
* Increased stormwater volume
* Drains
* Bank Armoring
* Channelization
* Erosion and sedimentation
* Drained/filled wetlands
* Alteration of hydrologic regime
* Surface or groundwater withdrawal
* Industrial discharges
* Intense impacts (golf course, feed lot, car wash)
References
Federal Interagency Team, 1998 Stream Corridor Restoration: An Interagency Handbook
Forman, R.T.T, and M. Godron 1986 Landscape Ecology. Wiley, New York
Malanson, George P. (1996) Riparian Landscapes Cambridge University Press
Michigan Natural Features Inventory, March 2001 Michigan County Elements List
Naiman, Robert J. and Henri Decamps (1997) The ecology of interfaces: Riparian Zones. Annu. Rev. Ecol. Syst. 1997. 28:621-58
Tilton, Don 1999 Rapid Assessment Method for Determining Wetland Functional Values
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