CONSERVATION DESIGN FORUM	COPY
	Landscape Architecture  Community Planning  Ecological Restoration  Resource Management

Floristic Inventory of Two Wetland Habitats
Located on the Indeck-Libertyville, LLC Site
Libertyville, Illinois

Floristic Inventory and Habitat Assessment Project No. 213900
Indeck-Libertyville, LLC Site - Libertyville, Illinois

Conservation Design Forum
31 August 1999
 

INTRODUCTION

On behalf of it's client, Conservation Design Forum (CDF) was asked to perform a floristic inventory of two wetland habitats located on the Indeck-Libertyville, LLC site. The wetlands were identified as jurisdictional wetland habitats via a standard wetland delineation procedure conducted in January of 1999. The purpose of this document is to present the results of a floristic inventory conducted on August 18th of this year. The exhibit included at the back of the report depicts the project location and delineated wetlands on the property.

METHODS

Two individual species lists were tallied, one for the south wetland (Wetland A), and the other for the north wetland (Wetland B). An analysis of the floristic quality of each area was determined using the Floristic Quality Assessment methodology as described by Swink and Wilhelm (1994), and Taft et al. (1997).
 

A useful method for determining the floristic quality of an area is through an analysis of the conservatism and diversity of species appearing in a plant inventory. Conservatism represents the degree to which an experienced field botanist has confidence that a given species is representative of a high quality, remnant habitat (i.e., those natural areas with intact presettlement structure, composition, and processes).  Native plants of a given region exhibit an observable range of conservatism. Therefore, each native species can be assigned a coefficient of conservatism (C value) ranging from 0 to 10, "weedy to conservative," reflecting this disposition.

The Mean C is the average coefficient of conservatism for a site. The floristic quality index (FQI) is a statistic derived by multiplying Mean C by the square root of the number of species inventoried. In general, sites with FQI values less than 20 are degraded or derelict plant communities, or are very small habitat remnants. Sites with FQI values in the twenties through low thirties suffer from various kinds of disturbance, but generally have potential for habitat restoration and recovery. When sites have FQI values in the middle thirties or higher, and/or have Mean C values of 3.4 or higher, one can be confident that there is sufficient native character present for the area to be at least regionally noteworthy. Sites with indices in the middle forties and higher are often also statewide significant natural areas.

RESULTS AND DISCUSSION

The results of the plant inventories and associated floristic quality assessments for each unit is presented in the appendix. The table below includes the total number of species inventoried and percent native for each wetland, and the native Mean C and FQI results. Photographs taken during the site visit are included at the back of the report.
 

SUMMARY
 

• In all probability, the number of plants inventoried from across these two wetlands represents no less than two-thirds of the existing vegetation. Based upon the results of the floristic quality assessment, these habitats are "borderline" natural areas.

• One of the plants recorded from the site is a state-listed threatened species. This plant is Carex crawei (early fen sedge).

GENERAL REFERENCES

The following sources were referenced in completing the final draft of this document.

Illinois Endangered Species Protection Board. 1994. Checklist of Endangered and Threatened Animals and Plants of Illinois. Endangered Species Protection Board, Springfield, Illinois.

Swink, F. and G. Wilhelm. 1994. Plants of the Chicago Region. 4th edition. Indiana Academy of Science, Indianapolis, Indiana.

Taft, J., G. Wilhelm, D. Ladd, and L. Masters. 1997. Floristic Quality Assessment for Vegetation in Illinois: A Method for Assessing Vegetation Integrity. Erigenia: 14, pp.3-95.

Wilhelm, G. and L. Masters.  1999.  Floristic Quality Assessment and Computer Applications. Conservation Research Institute. Elmhurst, Illinois.
 

Appendix

FLORISTIC QUALITY ASSESSMENT

The following is a summary of the inventory data generated using Wilhelm and Masters's Floristic Quality Assessment and Computer Applications, 1999.  Plant nomenclature follows Swink and Wilhelm's Plants of the Chicago Region, 1994. Data from each of the eleven permanent plots is presented in two sections as described below.

Section 1 includes three tables that summarize the inventory assessment data. The table to the left is an analysis of the floristic quality of the project area. In addition to listing the number of native species and total number of species, the mean coefficient of conservatism (MEAN C), floristic quality index (FQI), and mean wetness (MEAN W) values are presented. These are calculated once for native species only, and a second time including adventive species (W/Adventives). The two other tables summarize the number and percent of species in each physiognomic group (A = annual, B = biennial P perennial, W = woody, H = herbaceous).

Section 2 includes the species inventory arranged alphabetically, with each species preceded by its database acronym and coefficient of conservatism (C = 0 to 10, weedy to conservative), and followed by its wetness coefficient (W = -5 to + 5, wet to dry); corresponding national wetland indicator status (OBL = obligate wetland species, FAC = facultative species, UPL = upland species), physiognomic group, and common name. Adventive species are written in ALL CAPS and have an asterisk (*) for their C value.

The Mean C is the average coefficient of conservatism for the site. The FQI is derived by multiplying Mean C by the square root of the number of species present. In general, sites with FQI values less than twenty are degraded or derelict plant communities, or are very small habitat remnants. Sites with FQI values in the twenties through low thirties suffer from various kinds of disturbance, but generally have potential for habitat restoration and recovery. When sites have FQI values in the middle thirties or higher, one can be confident that there is sufficient native character present for the area to be at least regionally noteworthy. Sites with indices in the middle forties and higher are often also statewide significant natural areas.
 
 

Indeck Peaker Facility Site - WETLAND A
Locale: Libertyville, Lake County, Illinois
Date: August 18, 1 999
By: Conservation Design Forum (Johnson)
File: c:\FQAstudies\peakerA.inv

SECTION 1.  SUMMARY TABLES
 

SECTION 2.  SPECIES INVENTORY
 

Indeck Peaker Facility Site - WETLAND B
Locale: Libertyville, Lake County, Illinois
Date: August 18, 1 999
By: Conservation Design Forum (Johnson)
File: c:\FQAstudies\peakerB.inv

SECTION 1.  SUMMARY TABLES
 

SECTION 2.  SPECIES INVENTORY