FINAL REPORT Determination of Indicators of Ecological Change SERDP Project RC-1114A SEMPTEMBER 2004 Ramesh Reddy Joseph Prenger William F. DeBusk Wendy Graham Jennifer Jacobs Andrew Ogram Deborah Miller Suresh Rao George Tanner University of Florida Perdue University This report was prepared under contract to the Department of Defense Strategic Environmental Research and Development Program (SERDP). The publication of this report does not indicate endorsement by the Department of Defense, nor should the contents be construed as reflecting the official policy or position of the Department of Defense. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Department of Defense. Form Approved REPORT DOCUMENTATION PAGE OMB No. 0704-0188 The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to the Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. 1. REPORT DATE (DD-MM-YYYY) 2. REPORT TYPE 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S) 11. SPONSOR/MONITOR'S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT 13. SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF 18. NUMBER 19a. NAME OF RESPONSIBLE PERSON a. REPORT b. ABSTRACT c. THIS PAGE ABSTRACT OF PAGES 19b. TELEPHONE NUMBER (Include area code) Standard Form 298 (Rev. 8/98) Prescribed by ANSI Std. Z39.18 TABLE OF CONTENTS Page Executive Summary 1 1.0 Introduction 9 2.0 Technical Objectives 9 3.0 Results 10 3.1 Soil Biogeochemistry 10 3.1.1 Response of Soil Organic Carbon Dynamics to Disturbance by Military Training in the Southeastern U.S. 11 3.1.2 Influence of military land management on extracellular soil enzymes. 28 3.1.3 Distribution of Methanotrophs in Managed and Highly Degraded Watersheds 51 3.2 Vegetation 68 3.2.1 Vegetative indicators of disturbance in a chronically-disturbed ecosystem 69 3.2.2 Understory Vegetation and Soil response to silvicultural activity in a southeastern mixed pine forest: A chronosequence study. 79 3.3 Hydrology 109 3.3.1 Characterization and Modeling of Throughfall Temporal Variability for Forest Communities in the Southeastern U.S. 110 3.3.2 Hydrologic Indices of Watershed Scale Military Impacts in Fort Benning, GA. 137 3.3.3 Impacts on Soil Saturated Hydraulic Conductivity: Mechanized Military Training Characterization Using Five Measurement Methods. 171 i 3.3.4 Mechanized Military Training Impacts on Hydraulic Characteristics of Ridgetop Soils in a Forested Watershed. 188 3.4 Stream Water Quality 203 3.4.1 Ecological Indicators in Forested Watersheds: Relationships between Watershed Characteristics and Stream Water Quality in Fort Benning, GA. 204 3.4.2 Microbial Nutrient Cycling in the Riparian Zone and its Influence on Stream Chemistry. 228 3.5 Modeling and Synthesis 246 3.5.1 Multivariate analysis of soil biogeochemical parameters for assessment of ecological condition. 247 3.5.2 Quantitative analysis of soil nutrient concentrations with near infrared spectroscopy and partial least squares regression. 277 3.6 Summary 303 4.0 Project Milestones (FY2003) 339 5.0 Close-Out Plan 339 6.0 Publications, Theses, Dissertations, and Presentations 340 6.1 Publications 340 6.2 Theses and Dissertations 342 6.3 Presentations 342 ii EXECUTIVE SUMMARY Introduction: The goal of this research is to develop indicators of ecosystem integrity and impending ecological change that include natural variation and human disturbance. We are evaluating parameters related to properties and processes in the understory vegetation, soil and surface hydrology as potentially sensitive indicators of ecosystem integrity and ecological response to natural and anthropogenic factors. The basic premise is that soil serves as the central ecosystem component that links the quality of the terrestrial habitats (by influencing vegetation and its stability) and the aquatic habitats (via control of soil erosion and overland runoff). We have evaluated potential ecological indicators for sensitivity, selectivity, and ease of measurement. Indicator selection was based on those that 1) show a high correlation with ecosystem state, 2) provide early warning of impending change and 3) differentiate between natural ecological variation and anthropogenic negative impacts. In addition, we have attempted to determine the range of natural variation for indicator variables, and compared those with the range of values under anthropogenic, especially mission-related, influences. Our research and monitoring plan addresses the following five tasks: • Task 1 Soil/sediment quality indicators: Identification of physical, chemical and biological variables of soil that may be used as indicators of ecological change. Section 3.1 • Task 2 Vegetation indicators: Identification of species and community variables of vegetation that may be used as indicators of ecological change. Section 3.2 • Task 3 Hydrology: Identification of aspects of surface hydrology that may be used as indicators of ecological change. Section 3.3 • Task 4 Stream Water quality: Correlation of watershed hydrology and soil biogeochemistry in order to identify natural and anthropogenic influences on water quality. Section 3.4 • Task 5 Synthesis and modeling. Section 3.5 Findings and Accomplishments Severe impacts to soil, vegetation and hydrologic processes are associated with mechanized training involving tracked (tanks and Bradley) vehicles. Moderate to severe impacts also occur in several areas of non-military land use, primarily due to forest clear-cutting activities. Hydrologic and ecological impacts observed in wetlands and streams downslope from clear-cut upland areas were similar in nature to those observed in association with severe military disturbance; however, since silvicultural activities are typically shorter duration, the extent and severity of these disturbances are less and recovery more rapid than those associated with mechanized military activity. The soil, vegetation and hydrologic parameters (potential indicators) that were most closely correlated with pre-determined site disturbance levels (low, moderate, severe) were those that reflected loss of vegetation biomass and community structure, disruption and/or compaction of soil, and loss of soil A horizon (and soil organic matter) in uplands; and accelerated sedimentation of clay and sand in wetlands. In wetland areas downslope from impacted uplands, relationships between soil biogeochemical indicators and upland impacts were less clearly defined. However, indicators that directly related to wetland soil organic matter content (and “dilution” by clay or sand) were useful in identifying sediment- impacted wetlands located below severely-disturbed upland areas. The potential value of wetland soil biogeochemical properties as indicators of nutrient loading in uplands (e.g., from excessive fertilization or waste disposal) was not realized at the Fort Benning study areas, due to the nature of the ecological impacts in upland areas. Commonly observed impacts of mechanized training on soil and vegetation included: • Disturbance or destruction of vegetation communities, including ground cover (especially litter cover), understory and canopy vegetation. • Disruption of soil A horizon and effective burial or dilution of biologically-active topsoil with organic-poor lower horizons. • Compaction of subsoil, reducing soil permeability and increasing runoff and erosion potential. • Loss of A and E horizons in severely-impacted upland areas, rendering soil unsuitable for supporting native plant communities. • Gulley erosion in downslope areas, with significant sedimentation in wetlands and streams. • Short-circuiting of watershed flow paths with increased surface runoff and decreased subsurface detention in uplands (creating hydrologic and ecological imbalances in wetlands and streams). Summary of Accomplishments Soil Biogeochemistry The most promising soil biogeochemical indicators for upland areas were highly correlated with soil organic matter content and carbon (C) quality (biodegradability): • Total organic C - indicator of soil disturbance resulting from loss of topsoil (erosion) or mixing of A and E horizons. o Anthropogenic impacts on soil and ground cover in upland areas of the Fort Benning study site included (1) disturbance or destruction of vegetation, resulting in increased area of bare ground and a greater proportion of early successional