Measures of Successful Wetland Restoration: An Examination of Policies and Ecologies in Northern...
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Transcript of Measures of Successful Wetland Restoration: An Examination of Policies and Ecologies in Northern...
Measures of Successful Wetland Restoration:
An Examination of Policies and Ecologiesin Northern Michigan
Andrew T. Kozich
Michigan Technological University
Introduction
• Regulation of Michigan’s wetlands: DEQ
• Much mitigation activity: Road agencies
Three key DEQ mitigation policies
•Monitoring reports of mitigation sites must be submitted to the DEQ annually for 5 years
•Wetland acreage must be placed into conservation easement
• Invasive species at mitigation sites must be limited to 10% of total cover
Previous literature
• Hornyak & Halvorsen (2003): 48% of mitigation permit files in the western U.P. were missing monitoring reports, conservation easement documents, or both
• Invasive plant species often problematic at mitigation sites
(Balcombe et al 2005; Cole & Shafer 2002; Moore et al 1999; Spieles 2005; Spieles et al 2006)
Research Questions
• Have rates of site monitoring & conservation easements changed since 2003?
• Is there a relationship between site monitoring and invasive species?
• Do other site factors appear to be influencing levels of invasive species?
• What about creation versus restoration?
Research Design
• Examine all U.P. mitigation permit files from 2003 to 2006 (69 files; 37 mitigation sites)
• Examine mitigation sites constructed by road agencies between 2003 and 2006 (11 sites)
• Estimate compliance with 10% invasive species limit• Releve sampling• Created wetlands versus restored wetlands
Results
Monitoring report compliance:
• Michigan Dept. of Transportation:90%
• County road commissions:30%
• Other/public entities: 45%• Private entities:
50%
• Overall compliance:
54%(20 of 37 sites in compliance)
Results
Conservation easement compliance:
• Michigan Dept. of Transportation:29%
• County road commissions:38%
• Other/public entities: 50%• Private entities:
60%
• Overall compliance:
51%(19 of 37 sites in compliance)
Results
Compliance with 10% invasive species limit:
• 5 sites likely in compliance
• 5 sites likely out of compliance
• 1 site uncertain
• Overall compliance: 45%
Results
• Sites in compliance with invasive species: 60% had been monitored
• Sites non-compliant with invasive species: 60% had been monitored
Monitoring likely not related to levels of invasive species at mitigation sites
Results
Other factors influencing invasive species?
• Permittee
• Age of mitigation site
• Proximity to nearest road
Results
Number of invasive species related to mitigation site acreage
R2 = 0.74
0 1 2 3 4 5 6 70
1
2
3
4
5
6
7
8
Site size (acres)
# o
f in
vasi
ve s
pec
ies
R2 = 0.74
Further...
•100% of compliant sites were wetland restorations, constructed adjacent to natural wetlands
•80% of non-compliant sites were wetland creations, constructed adjacent to upland forests
Simple road re-location
Restoration
Fewer invasives(mean density 6.2%)
Pre-existing wetland hydrology
Smaller mitigation sites (mean = 1.8 acres)
Smaller mitigation sites (mean = 1.8 acres)
Large mitigationsites (mean = 4.2 acres)
Simple road re-location
Restoration
Pre-existing wetland hydrology
Multiple projects
Wetland hydrology questionable
More invasives(mean density 16.9%)
Creation
Fewer invasives(mean density 6.2%)
0 1 2 3 4 5 6 70
5
10
15
20
25%
co
ver
inva
sive
sp
ecie
s
Red = wetland creation
Green = wetland restoration
Site size (acres)
Summary
• Site monitoring & conservation easements: Very little change since 2003
• Site monitoring not related to invasive species, but landscape location is
• Smaller restoration projects more successful than larger creation projects
No Net Loss?
74 acres lost; 185 acres gained
Wetland acreage meeting performance standards for invasive species:
30%
Conclusions
• Mitigation practices in the U.P. are resulting in increased acreage but decreased overall quality of wetlands
• Policy efforts should emphasize the importance of mitigation site selection
• Restoration is the best option!
Questions?