Restoring Waterfowl Habitat and Potential Flood Storage Services on Wetland Reserve Program Lands in the Mississippi Alluvial Valley

Transcription

1 Restoring Waterfowl Habitat and Potential Flood Storage Services on Wetland Reserve Program Lands in the Mississippi Alluvial Valley J. Dale James, Ducks Unlimited Thomas E. Moorman, Ducks Unlimited Stephen P. Faulkner, USGS National Wetlands Research Center Stacey Shankle, Ducks Unlimited Corey Cofer, Ducks Unlimited A Conference on Ecosystem Services Naples, FL December 10, 2008

2 The Mississippi Alluvial Valley ~24.7 million acre physiographic province Formerly bottomland hardwood forest Frequent flooding influenced topography and plant communities Forest cover reduced by ~76% Spatial extent of flooding reduced by >50% Land use now dominated by agriculture

3 MAV is a highly diverse ecosystem

4 Wintering Waterfowl in the Mississippi Alluvial Valley Winters 4-7 million waterfowl Winters 1-4 million mallards ~40-50% continental mallard population Return ~4.3 million waterfowl each spring

5 USDA NRCS Wetland Reserve Program WRP established in 1990 Farm Bill Reauthorized in 2002, 2008 Farm Bills Incentives to retire farmed wetlands USDA NRCS administered program Purchase conservation easement & pay restoration costs Reforest, create HMUs AR, LA & MS ~600,000 acres in WRP Through 2007

6 Objectives 1. Estimate contribution of WRP restored lands to LMVJV waterfowl foraging habitat objectives by state and across tri-state 2. Qualitative assessment of habitat management of WRP lands 3. Estimate proportion of WRP lands within the 0-24 month flood frequency elevation using High Frequency Natural Flood Model

7 Methods Waterfowl Foraging Habitat Analysis WRP Hydrology Management Units using DU AUTOCAD files or individually mapped WRP Conservation Easement Database from USFWS LMVJV Remote sensing estimate of spatial extent of flooding for winters Within HMUs Within WRP Easement Polygons Assume water = potential foraging habitat, masked permanent water Qualitatively assessed plant species composition = Satisfactory, Marginal, or Unsatisfactory Characterized management intensity = Active, Passive, or Unmanaged Published energy/unit area values for habitat types adopted by LMVJV Summed HMU and Easement estimated foraging contributions Estimated foraging contribution of WRP by state, and combined across tri-state

8 Methods Waterfowl Foraging Habitat Analysis LMVJV WRP Habitat Foraging Values Pre-restoration harvested soybeans Post-restoration active moist soil Post-restoration passive moist soil Post-restoration 65% red oak/native pecan Post-restoration food plots (unharv. corn) 36 DEDs/ac 1,868 DEDs/ac 934 DEDs/ac 274 DEDs/ac 28,591 DEDs/ac DED = Duck-Energy-Day = existence energy required by a mallard-sized duck per day

9 Methods MAV High Frequency Natural Flood Model Synthesis of river gage data and classified satellite imagery River gage data select dates with bank-full or over-bank stage records Landsat 5 & 7 imagery to estimate spatial extent of flood events Winter dates with ~equal interval samples between bank-full and over-bank maximum for each stream segment Model flood stage-to-frequency relationships for 0-36 month events using: Peak Over Threshold (event peaks occur each time rise above or fall below bank-full) Monthly Peaks Analysis (maximum observed stage logged equal to or above bank-full) Flood frequency values = expected recurrence intervals from 0-36 months

10 Spatial Estimation of High Frequency Flooding in the MAV Memphis Two Year Flood Event Vicksburg

11 Estimate area of WRP easement within each flood frequency category Overlay easement polygon on flood depiction, calculate area Memphis Through 2007 Vicksburg

12 Results WRP Foraging Habitat Contribution across AR, LA & MS Estimated area flooded within 2,216, 2,747, 2,845, 2,862 HMUs Assessed plant species composition and management intensity n = 918 HMUs (LA & MS) Categorized 95% of HMUs as passive managed or unmanaged, 5% active 41% of area within HMU had Satisfactory plant species composition 59% of area within HMU had Marginal/Unsatisfactory plant species composition Undesirable plants = black willow, cockle burr, etc.

13 Results WRP Hydrology Management Unit Foraging Habitat Contribution across AR, LA & MS WRP HMUs provided 14,099 to 22,654 acres potential foraging habitat, range = annual variation in precipitation Net increase from pre-restoration condition of million DEDs across tri-state Represents ~ 4.5 to 7.2% of LMVJV Foraging Habitat Goals

14 Results WRP Easement Foraging Habitat Contribution across AR, LA & MS Natural flooding estimated on 1,046 to 1,431 easements from Represents 284,743 to 401,475 total easement acres Area flooded ranged from 8.8% to 30.7% (variation in annual precipitation) Beginning at stand age 20, reforested lands would provide estimated 7.89 to million DEDs Represents 2.2% to 5.8% of LMVJV Foraging Habitat Goal

15 Results WRP HMU and Easement Combined Foraging Habitat Contribution AR, LA & MS Restored WRP provided ~ to million DEDs more than pre-restoration conditions Range relates to variation in annual precipitation Represents 6.7% to 13.0% of LMVJV Foraging Objective

16 Results WRP HMU and Easement Combined Foraging Habitat Contribution AR, LA & MS If all HMUs were actively managed, with 95% actively managed moist soil habitat, and 5% area in managed food plot of unharvested corn: Restored WRP provided ~ million to million DEDs more than pre-restoration conditions Range relates to variation in annual precipitation Represents 13.1% to 23.4% of LMVJV Foraging Objective

17 Results High Frequency Flooding and WRP in the MAV Adequate gage data from 61 of 287 watersheds 180 watersheds had inadequate gage or no period of record data Assume sample (n = 61) is representative of other watersheds Assessed 365, 420, 462, and 498 easements in 2001, 2002, 2003, and 2004, respectively Represents 119,789 acres (2001) to 173,642 acres (2005) As of 2005 <77.7% of easement acres within the 0-24 month flood frequency As of 2005 <85.0% or easement acres had at least some observed flooding Model cannot estimate flood storage lack estimates of flood depth and duration

18 Conclusions WRP provides significant waterfowl foraging habitat in the MAV WRP could provide nearly twice foraging habitat with more intensive management of HMUs WRP site location in the MAV is very good with respect to retiring lands subject to high frequency flooding Remote sensing techniques facilitate landscape scale assessment of WRP, with some limitations No data or model of flood duration or depth to estimate flood retention capacity Additional work needed to understand this aspect of EGS at landscape scale

19 Thank you!