The Importance of
Healthy Riparian
Areas and their
Current Status in
Wisconsin
Tim Asplund, Buzz
Sorge (WI DNR)
Advanced Lake
Leaders – Green Lake
Sept. 26, 2013
Courtesy of MN DNR
Lakeshore zone
Shallow zone
Complexity:
The degree to which
both lakeshore and
shallow zones are
intact.
Complex habitats
facilitate movement
of food into and out
of lakes, provide
shelter and nesting
areas for fish an
wildlife, and buffer
human impacts.
Disturbance:
Shorelands and Shallows
Shorelands and Shallows
Shorelands and Shallows
Shorelands and Shallows
SHORELINE DEVELOPMENT
Shoreland Assessments
• Riparian Habitat
– Vegetation cover
– Shoreline and bank
– Trees and shrubs
• Littoral Habitat
– Bottom substrate
– Aquatic plants
– Fish habitat
• Human Influences
– Docks, piers, seawalls
– Buildings, lawns, driveways
Data: U.W. BioComplexity project
Fish grow ~3X faster in lakes
with lots of woody habitat
Undeveloped
Undeveloped
log
Low Development
Low Development
Growth
Rate
High Development
High Development
(mm/yr)
Woody Habitat (no./km)
From Schindler et al. 2000
FLOATING-LEAF VEGETATION
Number of plant species per
lake
50
FQI Score
45
40
35
30
25
20
2
4
6
8
10
12
14
16
18
Frequency of occurrance of
floating vegetation
Dwellings per km of shoreline
120
100
80
60
40
20
0
4
6
8
10
12
14
16
Dwelling per km of shoreline
Jennings et al 2003
18
45
40
35
30
25
20
15
10
2
4
6
8
10
12
14
16
Dwellings per km of shoreline
140
2
20
50
20
18
20
Shorelands and Shallows
Shorelands and Shallows
Shorelands and Shallows
2007 National Lake Assessment
Poor Biology is Three Times More
Common when Lakeshore Habitat is Poor
Regional summary:
• Northern Plains, Coastal
Plains and Xeric have
highest proportion of lakes
with poor habitat
conditions
• While Northern
Appalachian exhibits the
highest proportion of lakes
with high-quality habitat, >
25% of lakeshores are in
poor condition
NLA Physical Habitat and Human
Disturbance Indices
• Riparian (Lakeshore)
Vegetation Cover Index
• Littoral Habitat Cover
Index
• Littoral Habitat and
Lakeshore Vegetation
Complexity Index
• Riparian Disturbance
Intensity and Extent Index
Protocol
Littoral Zone
• Bottom substrate
• Aquatic macrophytes
• Fish cover
•
•
•
•
•
Riparian Zone
Canopy
Understory
Ground cover
Shoreline substrate
Human influence
Both
• Bank features
• Invasive species
Condition of the Nation’s Lakes: Habitat
Stressors to the Nation’s Lakes:
Extent, Relative Risk, and Attributable Risk
•
•
#1 – Lakeshore vegetation: Poor biology is three times more common when
lakeshore vegetation cover is in poor condition. This affects 36% of lakes.
#2 – Nutrients: Poor biology is 2.5 times more common when nutrients are high.
This affects about 20% of lakes.
Riparian Disturbance
pHab: Riparian Disturbance Index
NLA 2007 Weighted Percentage
0%
20%
40%
pHab: Riparian Disturbance Index
60%
80%
Nation
Region
MN
WI
MI
High
Missing
Low
Mid
High
Mid
Low
Missing
100%
Littoral Cover Index
pHab: Littoral Cover Index
NLA 2007 Weighted Percentage
0%
20%
40%
pHab: Littoral Cover Index
60%
80%
Nation
Region
MN
WI
MI
High
Missing
Low
Mid
High
Mid
Low
Missing
100%
Lakes sampled for shore habitat in
2012 and 2013
Goals of 2013 National Lake
Assessment Lakeshore Sampling
1) expand the assessment of lakeshore habitat condition
across Wisconsin
2) analyze lakeshore habitat condition in terms of lake
area and surrounding land use
3) Compare macrophyte survey methods: pointintercept vs. transect
4) develop ecoregion-specific lakeshore habitat metrics
for Wisconsin
5) Incorporate lakeshore habitat metrics into WisCALM
and Citizen Lakes Monitoring
6) use lakeshore habitat metrics in addition to trophic
status to assess lake health
• Restoring
Complexity and
Functional Values
of Shorelands