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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 1780’s Most of loss due to ditching and channelization and direct conversion to ag of nontidal wetlands
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From 1986-1997 there was an 80% reduction in loss from previous decade From 1982-1992 Delaware lost 2000 acres Delaware Wetland Status and Trends
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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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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 Multiple Levels of Assessment
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Nanticoke Wetland Study
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Overall Success Rate Permission for Access N = 446 45% 17% Granted No Contact Denied 38% No Contact Granted Denied 38% 44% 18% N = 321 TNC STATE
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Success Rate with Contact Excluding Public Lands N = 227 Percent 67% 33%
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Hydrogeomorphic Models Data Variable 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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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 Rapid Assessment (Level II)
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Mowing-3 Farmed-9 Grazing-3 Forest harvesting (>50% of stand) Recovered0 Recovering-5 Recent-7 Cleared not recovering-7 Excessive herbivory 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 Garbage/ isolated dumping Other Subtotal Habitat Community 10 + sum of above, if score <0 record 0 Habitat Category
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Rapid Assessment (Level II) Total Score (Hydrology/10) + (Hydrology/10)*(Biogeo/10)) + (Habitat/10) + ((Habitat/10)*(Landscape/10))
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Current projects Validating with HGM (level III) Determining sensitivity of methods Evaluating transferability to other areas of the state Rapid Assessment (Level II)
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Comparison of Effort to sample 50 sites 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 Level III Level II
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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 Multiple Levels of Assessment
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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 FunctionNo.Namesr 2 * Biogeochemistry5ex100 –ex500 –FOREVER100 –GRASS1000 FOREST1000 0.44 Habitat5+nat100 –nimpound1000 –FOREVER 100 –GRASS1000 FOREST1000 0.35 Hydrology3-ex100 –nat1000 +FORDEC10000.43 Plant2-ex1000 +FORDEC1000.17 * n=89, p<0.0001 for all models
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Stepwise multiple regression results for riverine HGM functions Variables FunctionNo.Namesr 2 * Biogeochemistry3-ex100 +nat1000 –DEVTOT1000.51 Habitat2-ex100 +nat10000.42 Hydrology5-ex100 +nat1000 +FOREST100 +FOREST1000 - FORDEC1000 0.70 Landscape6-ex100 –ex1000 +nat1000 –CROP100 –DEVTOT1000 +FOREVER1000 0.70 Plant2-ex500 –DEVTOT1000.31 * n=54, p<0.0001 for all models
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Assess loss and condition by subclass Determine Spatial Need to Restore Function Prioritize Restoration and Protection Projects Monitor to Determine Progress and Reassess Priorities Determine Stressors
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