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Evaluation of Restored Wetlands in the Prairie Pothole Region of the United States

Procedures/Methods

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Procedures for objective 1: Develop a region-wide database of restored wetlands to facilitate spatial and temporal characterizations of wetland restorations in the United States PPR.

Overview: Available information on wetlands restored by state, federal, and private resource agencies in the United States PPR will be gathered and consolidated into a region-wide electronic database. This database will be maintained by NPWRC (analogous to the Center Nest File) and will be continually updated by collaborators as new wetlands are restored or as restored wetlands are drained and put back into agriculture production. Information on restored wetlands will be obtained from National Wetland Inventory (NWI) maps, aerial photographs, and land-use records. Each wetland record will include information on: wetland location, geological landform, construction date, wetland class and size, type of restoration, project agency, project program, landowner, land-use history, and other available background information. Further, if available, past research conducted on wetlands will be catalogued. The purpose of this procedure is to develop the first major inventory of restored wetlands in the PPR and summarize existing demographic information on restored wetlands. Although, the major focus is to generate information on restored wetlands, this procedure will also generate information on created wetlands. Maps of restored wetlands will be gathered that can be overlaid with GIS information (e.g., NWI, geologic landform, state boundaries) available from NPWRC or other agencies. Maps and statistical summaries on wetland size, class, and other information will be used to characterize restored wetlands in the PPR and summarize trends to date. The NRCS and the FWS will be our primary collaborating agencies to develop the database.

1.a. Database Development

1.a.1. Sources and type of information available from agencies on restored wetlands was identified during several research planning meetings held in 1996. Based on this information, we developed a standard data-record sheet that will be used to consolidate pertinent information on each restored wetland.

1.a.2. The database will consist of individual wetland records. Record information will be maintained in a Statistical Analysis Systems database (SAS Institute, Inc. 1989). Each wetland record will initially have 20 data fields (Appendix III). The following descriptions correspond to information to be contained in each complete record of the database. The fields included in the database records are denoted by an asterisk (*).

ID number*

Each wetland will be assigned a unique identification number at NPWRC.

Geological landform*

Geological landform categories will be assigned by NPWRC (e.g., ground moraine, terminal moraine, dead ice moraine, etc.).

Restoration or creation*

Each wetland will be categorized as a restoration or creation based on the following definitions: Restoration is to rehabilitate a drained or filled wetland. Creation is the construction of a wetland on a site that was never a wetland.

Location

Location information will include the state*, county*, township*, range*, section*, 1/4 section*, and 40 acre parcel*.

Agency*

Name of the project agency(s) that restored or created the wetland (e.g., FWS, DU, NRCS).

Program*

Program(s) that facilitated the completed project (e.g., CRP, Wetland Reserve Program).

End-date of agreement*

End date (MM/DD/YY) for contractual agreement between the project agency and land owner. This is the date at which land owners are no longer responsible for maintaining each restored wetland.

Landowner*

Name of landowner.

Date construction completed*

Date (MM/DD/YY) that construction activities to restore or create wetlands ceased.

Class*

Targeted wetland class. Wetlands will be classified as Ephemeral (I), temporary (II), seasonal (III), semipermanent (IV), permanent (V), alkali (VI), and fen (VII) following Stewart and Kantrud (1971).

Surface area*

Area (acres) of wetland basin.

Pre-restoration drain*

Type of action to drain the wetland (e.g., surface drain, tile drain, pumped).

Surrounding land-use, current*

Land-use information within the catchment basin of each restored wetland will be described as idle grassland, pasture, hayland, small grains, row crops, and other.

Surrounding land-use, pre-restoration*

Similar information as listed above for current land-use, but before the basin was restored.

1.a.3. Information on restored wetlands will be provided by collaborators using files and existing databases. Because in many situations, information maintained on wetland location is not precise, agency personnel will identify the exact location of each restored wetland on aerial photographs. These aerial photographs will be used to identify restored wetlands on NWI maps. To facilitate gathering consistent information from agencies, we developed a "Wetland Restoration /Creation Record" (WRCR) card that lists all the information fields (Appendix III). Additionally, standardized codes for agencies, programs, land-use, and wetland class are included on the back of each WRCR card (Appendix III).

b.Updating the Database:

1.b.1. Once the database is established, new records will be added as additional wetlands are created or restored. We also will request that WRCR cards be filled out by NRCS offices in the event previously restored wetlands are drained. Collaborating agencies that performed the restorations will fill out WRCR cards and forward to NPWRC along with aerial photographs of each wetland.

c.Database Summaries:

1.c.1. GIS maps and statistical summaries describing the information on WRCR cards will be used to characterize the temporal and spatial extent of restoration activities. Information will be examined for trends such as which wetland classes were targeted for restoration and whether the pattern was consistent for physiographic region, state, or agency. This database will be made available to our collaborators.

Procedures for objective 2: Conduct a one-time extensive survey of seasonal and semipermanent wetlands in CRP to document the mean vegetative response given prerestoration site characteristics and land-use of various restorations in the United States PPR.

Overview: We will conduct an extensive investigation, May-August 1997, on seasonal and semipermanent wetlands in ground moraine (Glaciated Plains region) and dead ice/terminal moraines (Missouri and Prairie Coteau region). Because we will survey the wetlands only once, we will focus on a few easily measured vegetational and morphological variables (i.e., extensive variables) that are relatively stable on a temporal scale. The major focus will be to characterize wetlands restored as part of the CRP program or in similar grassland habitats. The physical measurements and vegetative attributes of restored wetlands in two age classes, 1-5 year and >5-10 year post restoration, will be compared with those of their drained and nondrained wetland analogues. Physical features will include morphology, soils, and current and past land-use. Biotic variables measured will be the number of vegetative zones and floristic diversity. The extensive survey on restored wetlands will document the mean vegetative response given prerestoration site characteristics and land-use. The outcomes will be summarized for managers to facilitate improvement of existing technology. Further, wetland classes resulting from the restoration activity and whether or not they were the wetland classes originally targeted will be evaluated. The physical and vegetative attributes of restored wetlands will be compared to their drained and nondrained analogues. These comparisons will provide a basis for evaluating restored wetlands and determine if and how soon restored wetlands recover to approximate their original condition. NPWRC also will provide summary datasets of extensive survey information to our collaborators to facilitate extrapolation of intensive investigations to a broader regional scale (See Objective 3).

2.a. Study Design and Site Selection:

2.a.1 We will select 12 replicate seasonal and 12 replicate semipermanent wetlands in ground moraine (Glaciated Plains) and combined terminal/dead ice moraine (Missouri and Prairie Coteau) landforms in the following wetland categories: 1) wetlands in CRP or similar grasslands restored for 1-5 yrs, 2)wetlands in CRP or similar grasslands restored for >5-10 yrs, 3) drained wetlands in CRP or similar grasslands (hereafter called drained analogue wetlands), and 4) wetlands in CRP or similar grasslands (hereafter called CRP analogue wetlands)(Table 1).

Table 1. Stratified sample of 192 wetland basins in the following strata.

Landform Wetland Class	Wetland Categories				Total
	Drained Analogue	Restored 1-5 yrs	Restored >5-10 yrs	CRP Analogue
Ground Moraine
Seasonal	12	12	12	12	48
Semipermanent	12	12	12	12	48
Terminal/Dead Ice Moraine
Seasonal	12	12	12	12	48
Semipermanent	12	12	12	12	48
Total	48	48	48	48	192

2.a.2 We will use a random-systematic sampling plan to define a representative geographic sample of wetlands along specific longitudinal and latitudinal gradients (see Study Area) within the PPR. To facilitate sampling we have drafted a GIS map of the PPR that shows the planned sampling locations in the Missouri and Prairie Coteau, and Glaciated Plains (Figure 1). A line has been drawn along the medial portion of each physiographic region that follows the long axis/natural orientation of these regions (Figure 1). Along these axis lines, we random-systematically placed 9 sampling points in the Missouri Coteau, 3 in the Prairie Coteau, and 12 in the Glaciated plains (Figure 1).

Figure 1. Location of wetland sample areas (dark circles) in the Missouri Coteau, Prairie Coteau, and Glaciated Plains.

2.a.3 At each sampling point, the nearest seasonal and semipermanent drained analogue, 1-5 year restored, >5-10 year restored, and CRP analogue wetlands will be selected for study that meet the following selection criteria:

1. Similar size (Based on NWI data):
   1. Seasonal wetlands within 0.4 - 0.8 ha.
   2. Semipermanent wetlands within 2.5 - 5.5 ha.
2. Landform:
   1. Wetlands in the Missouri and Prairie Coteau must be in ground moraine or dead ice moraine geologic landforms.
   2. Wetlands in the Glaciated Plains must be in ground moraine landforms.

2.b. Historic Survey:

2.b.1. Besides background information on restored wetlands generated in section 1.a.2. for the larger database, more detailed information collected will include length of time drained, completeness of drainage, and detailed cropping histories. Similarly, cropping information and drainage information will be collected for drained and CRP analogue wetlands. Much of this information will be provided by our NRCS collaborators.

2.c. Vegetation survey:

2.c.1 Vegetation sampling methods will follow those used by Kantrud and Newton (1996). Wetland vegetation will be sampled along four equally spaced transects that radiate out from the wetland center. In each vegetative assemblage (e.g., typha, typha/bulrush) bisected by a transect, a 1-m² quadrat will be centered in the middle of the assemblage, and cover classes (Daubenmire 1959) will be assigned to each macrophyte taxon in the quadrat. Additional quadrat information collected will include water depth and assigning a vegetative zone and phase (Stewart and Kantrud 1971). Other information collected will include width of vegetative assemblages bisected by transects and a list of all plant taxa not encountered in the quadrats. Total taxa recorded inside and outside the quadrats will be summed to provide a measure of taxon richness and floristic quality (Swink and Wilhelm 1994) for each plant community.

2.d. Soils/sediment:

2.d.1. Classifications of hydric soils will be provided by NRCS(Soil Taxonomy; Soil Survey Staff 1975)

2.d.2. Wetland soil samples will be collected at 10 cm increments to a depth of 20 cm using a 5-cm core sampler. Wetland soils will be collected within all vegetative sample plots (Section 2.c.1.). All soil samples collected will be sent to the USDA's Agricultural Research Service's soils lab, Morris, MN, for determination of organic and inorganic carbon (ARS 1997), and particle size (i.e., hydrometer method).

2.e. Morphology Survey:

2.e.1. A temporary benchmark (a wooden stake) will be established at each site to serve as a reference point for elevational measurements. Using a global positioning (GPS) unit and a laser level, we will determine the relative location and elevation of the wetland center, drainage plug, surface outlets and inlets, transition zones (e.g., upland/wetland, vegetation zones) and sample locations (i.e.,vegetation, soil).

2.e.2 Continuous GPS recordings will be collected while walking the wetland perimeter/watershed divide. This information will be used to determine shoreline length and catchment area, and to show the juxtaposition of physical features and sampling information relative to the wetland perimeter and catchment watershed.

2.f. Hydrology and Spatial Climatological Data:

2.f.1. Hydrologic information collected will include maximum water depth, number of surface outlets and inlets, percent open water, number of vegetative zones, and wetland classification. The number of vegetative zones, percent open water, and wetland classification will be determined from vegetation information collected in procedure 2.c.1. Maximum water depth is the difference in elevation between the lowest elevation of the wetland basin and lowest surface outlet elevation. Information to estimate maximum water depth and number of outlets and inlets will be collected in procedure 2.e.1.

2.f.2. Spatial climatic data will be gathered from the National Center for Atmospheric Research (Asheville, NC). Information will include rainfall, snowfall, relative humidity, and temperature.

2.g. Landscape Features:

Using aerial photographs, NWI maps, and NRCS land-use records, we will determine percent land-use, wetland density, and wetland class in landscapes surrounding the study wetlands.

2.h. Data analysis:

Appendix IV lists all the extensive variables we will measure during the extensive survey. Analysis of variance (ANOVA) techniques will be used to compare vegetation among wetland categories. Vegetative comparisons may include floristic quality (Swink and Wilhelm 1994), species richness, diversity (e.g., Shannon's, eveness), perennials/annuals, and natives/introduced. Two-way ANOVA's will be performed separately by wetland basin class (i.e., season and semipermanent).

We anticipate the following two-way-ANOVA to compare vegetative composition among wetland categories:

Source	df
Wetland Categorya	3
Regionb	2
Region*Wetland Category	6
Wetlant (Region Wetland Category)	84
Total	95
aWetland Categories = Drained analogue, Restored wetland (<5 yrs.), Restored wetland (>5-10 yrs.), CRP analogue.
bRegion = Missouri Coteau, Prairie Coteau, Glaciated Plains

Additionally, analysis of covariance may be used to evaluate variation associated with longitudinal and latitudinal gradients, where the covariate will be a derived gradient using a principal components approach. Further, depending on the replicability of land-use histories (e.g., length of time drained, cropping history, length of time restored) and landscape metrics (e.g., density and class of wetlands) wetland categories may be post-stratified to analyze other sources of variation.

Procedures for objective 3: Provide collaborators who are conducting intensive investigations with background information and linkage variables that can be used to extrapolate results from intensive studies to the larger regional sample.

Overview: The goal of this procedure is to provide collaborators who are conducting intensive investigations with summary datasets of extensive survey data to facilitate extrapolation of intensive investigations to a regional scale. This will be achieved by providing information generated under Objectives 1 and 2, and/or by collecting data on special "linkage variables" defined by our collaborators. Linkage variables are defined as additional variables needed by investigators of intensive studies to gain a regional perspective for their work. Collaborating scientists will provide detailed standard operating procedures for each linkage variable requested. At this time we have 21 collaborators who plan to conduct intensive studies as part of the overall effort and will use linkages provided by the extensive survey (Appendix II).

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