The Wetland Condition Index (WCI): Biological Indicators of Wetland Condition for Isolated Depressional Herbaceous Wetlands in Florida Report Submitted to the Florida Department of Environmental Protection under Contract #WM-683 By Charles R. Lane with Mark T. Brown, Mike Murray-Hudson, and M. Benjamin Vivas H.T. Odum Center for Wetlands University of Florida Gainesville, FL 32611-6350 September 2003 ACKNOWLEDGMENTS This research was supported under a research contract from the Florida Department of Environmental Protection (FDEP); M.T. Brown, principal investigator. We would like to acknowledge the support of FDEP staff, especially Russ Frydenborg, Ashley O’Neal, Ellen McCarron, Liz Miller, Lori Wolfe, Joy Jackson, Johnny Richardson, and the FDEP Central Laboratory in Tallahassee. Additional acknowledgement is due to the research group of the H.T. Odum Center for Wetlands, especially Kelly Reiss, Matt Cohen, Jim Surdick, and Susan Carstenn. We also thank the members of the 1999 and 2000 field crew for their tireless and enthusiastic work, especially Mark Fowlkes, Mark Otto, and Michael Stevens. Steven Doherty was an integral part of the initial stages of this research, and his perseverance and hard work helped to ensure this research to fruition. This project and the preparation of this report were funded in part by a Section 319 Nonpoint Source Management grant from the U.S. Environmental Protection Agency through a contract with the Florida Department of Environmental Protection. ii TABLE OF CONTENTS Page ACKNOWLEDGMENTS .................................................................................................. ii LIST OF TABLES............................................................................................................ vii LIST OF FIGURES ........................................................................................................... xi EXECUTIVE SUMMARY ............................................................................................. xiii CHAPTER 1 INTRODUCTION AND OVERVIEW ........................................................................1 Introduction...................................................................................................................1 GIS Measurements and Wetland Metrics..............................................................2 Regional Composition...........................................................................................4 Environmental Correlates and Assemblage Response ..........................................4 Background...................................................................................................................4 Wetland Trends.............................................................................................................6 Effect of Land Use Change on Wetland Systems.........................................................7 Nutrient and Chemical Loading ............................................................................9 Selective Herbivory and Trampling ....................................................................10 Ancillary Impacts from Landscape Modification................................................10 Wetland Assemblages and Biological Assessment ....................................................11 Project Overview ........................................................................................................12 2 DIATOMS AS BIOINDICATORS............................................................................13 Introduction.................................................................................................................13 Methods ......................................................................................................................14 Site Selection and Agricultural Development Gradient ......................................14 Field Data Collection, Sample Preparation and Laboratory Procedures.............15 Diatoms ........................................................................................................15 Soil and water physical-chemical sampling and analysis ............................16 Data Analyses......................................................................................................16 Summary statistics........................................................................................16 Diatoms-compositional tests ........................................................................17 Diatoms community composition and correlation with soil and water parameters...............................................................................................17 Metric Development............................................................................................18 iii Sensitive and tolerant taxa............................................................................19 Autecological metrics...................................................................................19 Constructing the Multimetric Index ....................................................................20 Results.........................................................................................................................20 Wetland Diatom Composition.............................................................................20 Diatom Composition and Environmental Correlates ..........................................26 Metric Development............................................................................................29 Regional composition...................................................................................29 Indicator species analyses ............................................................................31 Autecological indices ...................................................................................37 The Multimetric Index.........................................................................................42 Discussion...................................................................................................................44 Diatom Composition and Environmental Correlates ..........................................44 Diatom Composition and Wetland Regions........................................................46 Metric Development............................................................................................46 Indicator species analysis .............................................................................46 Autecological indices ...................................................................................47 The Diatom Multimetric Index–Conclusion and Recommendations..................47 3 MACROPHYTES AS BIOINDICATORS ................................................................49 Introduction.................................................................................................................49 Methods ......................................................................................................................50 Site Selection and Disturbance Gradient.............................................................50 Field Data Collection...........................................................................................52 Database Development........................................................................................53 Species characteristics..................................................................................53 Coefficient of Conservatism.........................................................................54 Soil and Water Physical-Chemical Sampling and Analysis................................54 Data Analyses......................................................................................................55 Summary statistics........................................................................................55 Macrophytes-compositional analysis ...........................................................55 Macrophyte composition and soil and water parameter correlates ..............55 Metric Development............................................................................................55 Sensitive and tolerant species.......................................................................56 Exotic species...............................................................................................56 Annual to perennial ratio..............................................................................56 Average Coefficient of Conservatism ..........................................................56 Vegetative Index of Wetland Condition..............................................................57 Results.........................................................................................................................57 Field Data ............................................................................................................57 Ancillary Data .....................................................................................................57 Compositional Analysis.......................................................................................59 Community Composition and Environmental Gradients ....................................60 Metric Development............................................................................................62 Sensitive and tolerant species.......................................................................62 Percent exotic ...............................................................................................69