Development of Multi-tiered Wetland Assessment Methods for Monitoring Wetland Condition

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Development of Multi-tiered Wetland Assessment
Methods for Monitoring Wetland Condition

• Amy Deller Jacobs
• DE Department of Natural Resources and
  Environmental Control

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Delaware Wetland Status and Trends

• 54 lost since 1780s
• Most of loss due to ditching
• and channelization and
• direct conversion to ag of
• nontidal wetlands

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Delaware Wetland Status and Trends

• From 1986-1997 there was an 80 reduction in loss
  from previous decade
• From 1982-1992
• Delaware lost
• 2000 acres

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Why Monitor Condition?

• Evaluate what functions are being
• performed and at what level
• Determine stressors
• Gain information to guide
• restoration and enhancement
• Meet requirements of TMDL
• lawsuit/ Required under Clean
• Water Act

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Multiple Levels of Assessment
LEVEL 1 GIS Platform No Fieldwork LEVEL 2 Rapid
Assessment Some Fieldwork LEVEL 3 Intensive
Field Sampling
Level of Effort Increases
Level of Detail Decreases
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Nanticoke Wetland Study
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Overall Success RatePermission for Access
TNC
STATE
No Contact
No Contact
45
38
44
38
Granted
Granted
17
18
Denied
Denied
N 446
N 321
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Success Rate with Contact Excluding Public Lands
N 227
67
Percent
33
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Hydrogeomorphic Models
Data
Variable
Variable
Variable
Variable
Variable
Function
Function
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HGM Function Wildlife Habitat
(Vdisturb ((Vtba Vtden)/2) Vshrub Vsnag)/4
Results are between 0 and 1
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Total Effort
24 man-hours
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Rapid Assessment (Level II)

• Development of a Rapid Assessment Method
• Evaluates condition and can distinguish various
  levels
• Requires a site visit
• No detailed data collected

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Rapid Assessment (Level II)

• Based on HGM models and field experience
• Evaluates stressors present at a site
• Weights stressors according to their impact on 4
  categories (hydrology, habitat, biogeo cycling,
  and landscape)
• Provides one overall score of the condition of
  the wetland

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Mowing -3
Farmed -9
Grazing -3
Forest harvesting (gt50 of stand) Forest harvesting (gt50 of stand)
Recovered 0
Recovering -5
Recent -7
Cleared not recovering -7
Excessive herbivory
Presense of invasive spp. Presense of invasive spp.
Dominate the site -7
Do NOT dominate the site -2
Chemical defoliation -3
Managed or converted to pine -5
Burned -3
Trails -1
Garbage/ isolated dumping -1
Other
Subtotal Habitat Community 10 sum of above, if score lt0 record 0
Habitat Category


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Rapid Assessment (Level II)
Total Score (Hydrology/10) (Hydrology/10)(Biog
eo/10)) (Habitat/10) ((Habitat/10)(Landscape/
10))
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Rapid Assessment (Level II)

• Current projects
• Validating with HGM (level III)
• Determining sensitivity of methods
• Evaluating transferability to other areas of the
  state

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Comparison of Effort to sample 50 sites
Level III
Level II

• 4 hours/ site
• 4 person crew
• 25 days(2 sites/day)
• 100 person-days
• Several hours office work

• 2 hours/ site
• 2 person crew
• 12.5 days (4 sites/ day)
• 25 person-days
• Minimal office work

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Multiple Levels of Assessment
LEVEL 1 GIS Platform No Fieldwork LEVEL 2 Rapid
Assessment Some Fieldwork LEVEL 3 Intensive
Field Sampling
Level of Effort Increases
Level of Detail Decreases
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Landscape Level Assessment (I)

• Inventory status and trends
• Updated wetland maps
• Including HGM modifiers
• Provide additional information
• Landscape analysis
• Inferring condition based on indicators in
  surrounding landscape

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Stepwise multiple regression results for flat HGM
functions
Variables
Function No. Names r2
Biogeochemistry 5 ex100 ex500 FOREVER100 GRASS1000 FOREST1000 0.44
Habitat 5 nat100 nimpound1000 FOREVER 100 GRASS1000 FOREST1000 0.35
Hydrology 3 -ex100 nat1000 FORDEC1000 0.43
Plant 2 -ex1000 FORDEC100 0.17
n89, plt0.0001 for all models
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Stepwise multiple regression results for riverine
HGM functions
Variables
Function No. Names r2
Biogeochemistry 3 -ex100 nat1000 DEVTOT100 0.51
Habitat 2 -ex100 nat1000 0.42
Hydrology 5 -ex100 nat1000 FOREST100 FOREST1000 -FORDEC1000 0.70
Landscape 6 -ex100 ex1000 nat1000 CROP100 DEVTOT1000 FOREVER1000 0.70
Plant 2 -ex500 DEVTOT100 0.31
n54, plt0.0001 for all models
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Determine Stressors
Monitor to Determine Progress and Reassess
Priorities
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