Response of Fish Communities to Cropland

Density and Natural Environmental Setting

in the Eastern Highland Rim Ecoregion of the

Lower Tennessee River Basin, Alabama and

Tennessee, 1999

Water-Resources Investigations Report 02-4268

National Water-Quality Assessment Program

U.S. Department of the Interior

U.S. Geological Survey
Cover photographs: Background photograph is the Duck River at Osteen Bend (river mile 173.1), 

Marshall County, Tennessee (Photograph by Rodney Knight, USGS). Left photo is the Northern studfish—

Fundulus catenatus (Photograph by Rodney Knight, USGS). Right photo is the Slackwater Darter—

Etheostoma boschungi (Photograph by J.R. Shute, Conservation Fisheries, Inc. Used with permission.)
Response of Fish Communities to Cropland Density 

and Natural Environmental Setting in the Eastern 

Highland Rim Ecoregion of the Lower Tennessee 

River Basin, Alabama and Tennessee, 1999

By Jeffrey R. Powell

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 02-4268

Nashville, Tennessee

2003
U.S. DEPARTMENT OF THE INTERIOR

Gale Norton, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

Any use of trade, product, or firm name in this report is for identification

purposes only and does not constitute endorsement by the

U.S. Geological Survey.

For additional information write to: Copies of this report may be purchased from:

District Chief U.S. Geological Survey

U.S. Geological Survey Branch of Information Services

640 Grassmere Park, Suite 100 Box 25286

Nashville, Tennessee 37211 Denver, Colorado 80225-0286

More information about the National Water-Quality Assessment (NAWQA) Program is available via the World Wide 

Web at: http://water.usgs.gov/nawqa/naqwa_home.html
The U.S. Geological Survey (USGS) is committed to serve the Nation with accurate and timely scientific information that helps enhance and protect the 

overall quality of life, and facilitates effective management of water, biological, energy, and mineral 

resources. Information on the quality of the Nation’s 

water resources is of critical interest to the USGS 

because it is so integrally linked to the long-term 

availability of water that is clean and safe for drinking 

and recreation and that is suitable for industry, irrigation, and habitat for fish and wildlife. Escalating population growth and increasing demands for the multiple 

water uses make water availability, now measured in 

terms of quantity and quality, even more critical to the 

long-term sustainability of our communities and ecosystems.

The USGS implemented the National WaterQuality Assessment (NAWQA) Program to support 

national, regional, and local information needs and 

decisions related to water-quality management and 

policy. Shaped by and coordinated with ongoing 

efforts of other Federal, State, and local agencies, the 

NAWQA Program is designed to answer: What is the 

condition of our Nation’s streams and ground water? 

How are the conditions changing over time? How do 

natural features and human activities affect the quality 

of streams and ground water, and where are those 

effects most pronounced? By combining information 

on water chemistry, physical characteristics, stream 

habitat, and aquatic life, the NAWQA Program aims to 

provide science-based insights for current and emerging water issues and priorities. NAWQA results can 

contribute to informed decisions that result in practical 

and effective water-resource management and strategies that protect and restore water quality.

Since 1991, the NAWQA Program has implemented interdisciplinary assessments in more than 50 

of the Nation’s most important river basins and aquifers, referred to as Study Units. Collectively, these 

Study Units account for more than 60 percent of the 

overall water use and population served by public 

water supply, and are representative of the Nation’s 

major hydrologic landscapes, priority ecological 

resources, and agricultural, urban, and natural sources 

of contamination. 

Each assessment is guided by a nationally consistent study design and methods of sampling and 

analysis. The assessments thereby build local knowledge about water-quality issues and trends in a particular stream or aquifer while providing an 

understanding of how and why water quality varies 

regionally and nationally. The consistent, multi-scale 

approach helps to determine if certain types of waterquality issues are isolated or pervasive, and allows 

direct comparisons of how human activities and natural processes affect water quality and ecological health 

in the Nation’s diverse geographic and environmental 

settings. Comprehensive assessments on pesticides, 

nutrients, volatile organic compounds, trace metals, 

and aquatic ecology are developed at the national 

scale through comparative analysis of the Study-Unit 

findings. 

The USGS places high value on the communication and dissemination of credible, timely, and relevant science so that the most recent and available 

knowledge about water resources can be applied in 

management and policy decisions. We hope this 

NAWQA publication will provide you the needed 

insights and information to meet your needs, and 

thereby foster increased awareness and involvement in 

the protection and restoration of our Nation’s waters. 

The NAWQA Program recognizes that a 

national assessment by a single program cannot 

address all water-resource issues of interest. External 

coordination at all levels is critical for a fully integrated understanding of watersheds and for costeffective management, regulation, and conservation of 

our Nation’s water resources. The Program, therefore, 

depends extensively on the advice, cooperation, and 

information from other Federal, State, interstate, 

Tribal, and local agencies, non-government organizations, industry, academia, and other stakeholder 

groups. The assistance and suggestions of all are 

greatly appreciated.

Robert M. Hirsch

Associate Director for Water

FOREWORD

Foreword iii
Contents v

CONTENTS

Abstract.................................................................................................................................................................................. 1

Introduction ........................................................................................................................................................................... 1

Purpose and Scope....................................................................................................................................................... 3

Description of the Eastern Highland Rim Ecoregion .................................................................................................. 3

Physiography and Land Use ............................................................................................................................. 4

Fauna and Flora ................................................................................................................................................. 7

Historical Land Use ........................................................................................................................................... 8

Acknowledgments ....................................................................................................................................................... 9

Study Design.......................................................................................................................................................................... 10

Sampling Methods................................................................................................................................................................. 10

Environmental Characteristics..................................................................................................................................... 10

Fish Communities........................................................................................................................................................ 13

Analytical Methods................................................................................................................................................................ 15

Environmental Characteristics..................................................................................................................................... 15

Fish Communities........................................................................................................................................................ 15

Response of Fish Communities to Cropland Density and Environmental Characteristics ......................................... 17

Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion ......................................... 17

Physical Characteristics............................................................................................................................................... 17

Variation of Natural Environmental Setting within the Eastern Highland Rim Ecoregion......................................... 20

Water Chemistry.......................................................................................................................................................... 23

Fish Communities........................................................................................................................................................ 24

Response of Fish Communities to Cropland Density and Natural Environmental Setting......................................... 26

Conclusions ........................................................................................................................................................................... 35

References ............................................................................................................................................................................. 36

Appendixes ............................................................................................................................................................................ 39

1. Summary of indirect gradient analysis relating site scores from the correspondence analysis 

and principal components analysis of the fish-community data to selected habitat, hydrology, 

and land-use variables for 20 sites in the Eastern Highland Rim Ecoregion .......................................................... 41

2. Correspondence analysis biplot illustrating the relation among fish communities 

for 20 sites in the Eastern Highland Rim Ecoregion............................................................................................... 42

3. Fish species and the number of individuals collected at 20 sites in the Eastern Highland Rim Ecoregion............ 43

4. Fish species, tolerance class, trophic guild, and reproductive group for species 

collected at 20 sites in the Eastern Highland Rim Ecoregion ................................................................................. 47
vi Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

FIGURES

1-3. Maps showing:

1. Location of the lower Tennessee River Basin study unit, physiographic provinces, 

level IV ecoregions, and the Eastern Highland Rim Ecoregion ........................................................................ 2

2. Location of sampling sites, generalized geology, and suggested subgroups in the 

Eastern Highland Rim Ecoregion of the lower Tennessee River Basin ............................................................ 5

3. Land use in the Eastern Highland Rim Ecoregion of the lower Tennessee River Basin................................... 6

4. Principal components analysis biplot illustrating the relation among habitat, hydrology, 

and land-use variables for 20 sites in the Eastern Highland Rim Ecoregion ............................................................. 19

5. Boxplots showing differences in elevation and streamflow among 20 sites in the Eastern 

Highland Rim Ecoregion, summarized by natural setting or ecoregion subgroup .................................................... 20

6. Principal components analysis biplot illustrating the relation among habitat, hydrology, 

and land-use variables for 11 sites in the Dissected Tablelands................................................................................. 22

7. Scatter plots showing the comparison of cropland density to site scores from the first axis of the principal 

components analysis and substrate embeddedness for 11 sites in the Dissected Tablelands..................................... 23

8. Principal components analysis biplot illustrating the relation among water-chemistry 

variables for 11 sites in the Dissected Tablelands...................................................................................................... 24

9. Scatter plots showing the comparison of cropland density to site scores from the 

first axis of the principal components analysis and to nitrate 

concentrations for 11 sites in the Dissected Tablelands............................................................................................. 26

10. Correspondence analysis biplot illustrating the relation among fish abundances 

for 11 sites in the Dissected Tablelands ..................................................................................................................... 28

11. Principal components analysis biplot illustrating the relation among fish-community metrics 

for 11 sites in the Dissected Tablelands ..................................................................................................................... 31

12. Graphs showing response of selected fish-community metrics to site scores from 

axis 1 of the principal components analysis............................................................................................................... 34

TABLES

1. Basin characteristics of sampling sites for fish community, water chemistry, and physical habitat 

in the Eastern Highland Rim Ecoregion of the lower Tennessee River Basin ........................................................... 11

2. Habitat, hydrology, and land-use variables used to characterize sites in the Eastern Highland Rim 

Ecoregion of the lower Tennessee River Basin .......................................................................................................... 12

3. Water-chemistry variables used to characterize sites in the Eastern Highland Rim Ecoregion 

of the lower Tennessee River Basin ........................................................................................................................... 13

4. Fish-community metrics used to summarize groups of fishes in the Eastern Highland Rim Ecoregion ................... 16

5. Summary statistics from the principal components analysis of the habitat, hydrology, and 

land-use variables for 20 sites in the Eastern Highland Rim Ecoregion .................................................................... 18

6. Summary statistics from the principal components analysis of the habitat, hydrology, and 

land-use variables for 11 sites in the Dissected Tablelands ....................................................................................... 21

7. Summary statistics from the principal components analysis of the water-chemistry variables for 

11 sites in the Dissected Tablelands........................................................................................................................... 25

8. Fish species collected at 11 sites in the Dissected Tablelands ................................................................................... 27

9. Summary statistics from the correspondence analysis of the fish-abundance data for 

11 sites in the Dissected Tablelands........................................................................................................................... 29

10. Summary statistics from the principal components analysis of the community metrics for 

11 sites in the Dissected Tablelands........................................................................................................................... 29

11. Summary of fish-community metrics and Index of Biological Integrity scores for 

11 sites in the Dissected Tablelands........................................................................................................................... 30

12. Summary of indirect gradient analysis relating site scores from the correspondence analysis 

and principal components analysis of the fish-community data to selected habitat, 

hydrology, and land-use variables for 11 sites in the Dissected Tablelands .............................................................. 32

13. Summary of indirect gradient analysis relating site physical and water-chemistry data scores 

from the principal components analysis and cropland density to fish-community 

metrics for 11 sites in the Dissected Tablelands ........................................................................................................ 33
Contents vii

CONVERSION FACTORS, DATUM, WATER-QUALITY UNITS, AND LIST OF ACRONYMS AND 

ABBREVIATIONS

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C = (°F - 32) / 1.8

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Water-quality units

μg/L micrograms per liter

mg/L milligrams per liter

μS/cm microsiemens per centimeter

col./100 mL colonies per 100 milliliters

Acronyms

BSI Bank stability index

CA Correspondence analysis

CAFO Confined animal feeding operations

DT Dissected Tablelands

EDA Exploratory data analysis

EHR Eastern Highland Rim

ERDAS Earth Resources Data Acquisition Services

HHL Habitat, hydrology, and land use

IBI Index of Biological Integrity

IGA Indirect gradient analysis

LTEN Lower Tennessee

MV Moulton Valley

MVSP Multivariate Statistical Package

NAWQA National Water-Quality Assessment

NWQL National Water Quality Laboratory

PCA Principal components analysis

TVA Tennessee Valley Authority

USGS U.S. Geological Survey

Multiply By To obtain

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

acre 0.4047 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2)

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)
Introduction 1

ABSTRACT

Response of fish communities to cropland 

density and natural environmental setting were 

evaluated at 20 streams in the Eastern Highland 

Rim Ecoregion of the lower Tennessee River 

Basin during the spring of 1999. Sites were 

selected to represent a gradient of cropland densities in basins draining about 30 to 100 square 

miles. Fish communities were sampled by using a 

combination of seining and electrofishing techniques. A total of 10,550 individual fish, representing 63 species and 15 families, were collected 

during the study and included the families Cyprinidae (minnows), 18 species; Percidae (perch 

and darters), 12 species; and Centrarchidae (sunfish), 12 species. Assessments of environmental 

characteristics, including instream and terrestrial 

data and land-cover data, were conducted for each 

site. Instream measurements, such as depth, 

velocity, substrate type, and embeddedness, were 

recorded at 3 points across 11 equidistant 

transects at each site. Terrestrial measurements, 

such as bank angle, canopy angle, and canopy 

closure percentage, were made along the stream 

bank and midchannel areas. Water-quality data 

collected included pH, dissolved oxygen, specific 

conductivity, water temperature, nutrients, and 

fecal-indicator bacteria. 

Substrate embeddedness was the only variable correlated with both cropland density and 

fish communities (as characterized by ordination 

scores and several community level metrics). 

Multivariate and nonparametric correlation techniques were used to evaluate fish-community 

responses to physical and chemical factors associated with a cropland-density gradient, where the 

gradient was defined as the percentage of the 

basin in row crops. Principal component analysis 

and correspondence analysis suggest that the 

Eastern Highland Rim Ecoregion is composed of 

three subgroups of sites based on inherent physical and biological differences. Data for the subgroup containing the largest number of sites were 

then re-analyzed, revealing that several environmental variables, such as nutrient concentrations, 

stream gradient, bankfull width, and substrate 

embeddedness, were related to cropland density; 

however, only a subset of those variables (substrate embeddedness, elevation, and streamflow) 

were related to fish communities. Results from 

this analysis suggest that although many waterquality and habitat variables are covariant with 

cropland density, most of the variables do not significantly affect fish-community composition; 

instead, fish communities primarily respond to the 

cumulative effects of sedimentation.

INTRODUCTION

In 1997, the U.S. Geological Survey (USGS) 

began an assessment of the Lower Tennessee (LTEN) 

River Basin as part of the National Water-Quality 

Assessment (NAWQA) Program. The goals of the program are to describe the status of and trends in the 

Nation’s surface- and ground-water resources by 

developing an understanding of the factors that influence current water-quality conditions (Hirsch and others, 1988). The LTEN River Basin, one of the 59 study 

areas located in the conterminous United States, 

extends from Chattanooga, Tenn., to its confluence 

with the Ohio River near Paducah, Ky. (fig. 1). The 

LTEN River Basin has one of the most diverse fish 

faunas of any river system in North America, supporting approximately 193 native species (Etnier and 

Response of Fish Communities to Cropland Density and 

Natural Environmental Setting in the Eastern Highland 

Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

By Jeffrey R. Powell
2 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

KENTUCKY

88°

88°

87°

87°

86°

86°

36° 36°

35° 35°

Duck

River

Elk

River

Clar ks

River

Buffalo

River

Sho a l Creek

Bear

Creek

Flint Creek

Flint

Paint R ock

Ri v er

Beech River

Sequatchie River

Paducah

River

Kentucky

Lake

Wheeler

Lake Wilson Lake

Pickwick

L ake

Tennessee

River

Woods

Reservoir

Normandy

Lake

Tims Ford

Lake

Nickajack

Lake

Guntersville

Lake

Big

Sandy River

TENNESSEE

GEORGIA

Chattanooga

Columbia

TENNESSEE

ALABAMA

MISSISSIPPI

Huntsville

Decatur

Florence

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

Study unit

Town Creek

Base from U.S. Geological Survey,

1:2,000,000 digital line graph

Mississippi Alabama Georgia

Kentucky

Tennessee

COASTAL

PLAIN

INTERIOR LOW PLATEAU

APPALACHIAN

PLATEAUS

Physiographic Provinces

Eastern Highland

Rim Ecoregion

Figure 1. Location of the lower Tennessee River Basin study unit, physiographic provinces, level IV ecoregions, and the

Eastern Highland Rim Ecoregion.

Eastern Highland Rim boundaries modified from King and Beikman, 1974;

Smalley, 1983; Osborne and others, 1989; and Griffith and others, 1997

Winchester

20 40 MILES

0 20 40 KILOMETERS

0

LEVEL IV ECOREGION

Modified from Griffith and others, 1997;

King and Beikman, 1974; Osborne and

others, 1989; and Smalley, 1983

Base from U.S. Geological Survey,

1:2,000,000 digital line graph

TENNESSEE

ALABAMA

MISSISSIPPI GEORGIA

SOUTHEASTERN PLAINS AND HILLS

TRANSITION HILLS

WESTERN HIGHLAND RIM

OUTER NASHVILLE BASIN

INNER NASHVILLE BASIN

EASTERN HIGHLAND RIM

CUMBERLAND PLATEAU

PLATEAU ESCARPMENT

SOUTHERN LIMESTONE/DOLOMITE VALLEYS

AND LOW ROLLING HILLS

Little Mountain

KENTUCKY

TENNESSEE

Little Mountain
Introduction 3

Starnes, 1993; Mettee and others, 1996). Dams and 

other anthropogenic stressors contributing to waterquality impairment and habitat destruction are the 

greatest threats to this rich fauna (Etnier, 1997). These 

types of stressors not only affect aquatic inhabitants 

but also jeopardize domestic drinking-water supplies 

and the recreational value of the resource.

In Alabama and Tennessee, agriculture is the 

most frequently mentioned source of impairment to 

streams and rivers in the LTEN River Basin (Tennessee Department of Environment and Conservation, 

2000; Alabama Department of Environmental Management, 2000). The constituent most frequently cited 

as the cause of impairment is sediment. Other causes 

of impairment that frequently accompany sedimentation from agricultural sources include pathogens associated with animal waste, altered channel morphology 

and habitat loss, nutrients that cause excessive algal 

growth, and chemical pollutants originating from cultivated row crops. 

The emphasis on agriculture and its potential 

effect on rivers, streams, and biota is a growing concern nationwide. Reports from the U.S. Environmental 

Protection Agency list siltation from agriculture as the 

most important of all river pollutants—more than 

three times higher than forestry, mining, or urban 

development (Waters, 1995). Although some form of 

agriculture occupies nearly one-third of the surface 

area of the continental United States, the types of agricultural activities are variable and lead to a wide array 

of agricultural byproducts that have the potential to 

reach streams. These byproducts can vary from acute 

pesticide exposures to chronic erosion and sedimentation from livestock-trampled stream banks. Cooper 

(1993) suggests that sometimes the more subtle, 

chronic exposures may be as damaging as acute exposures. Although the response from acute exposures 

may be more noticeable at first (for example, fish 

kills), the results from long-term exposures may be 

more damaging. 

One objective of the NAWQA Program is to 

provide an understanding of how changing land-use 

patterns affect the chemical, physical, and biological 

make-up of streams. Relating change in fish communities to chemical and physical variability is critical in 

understanding how streams are affected by land-use 

practices, such as agriculture. Although most ichthyologists accept that large-scale differences in fish distributions are controlled by natural factors, such as 

geology and climate, trends associated with changing 

land-use patterns can play a significant role in determining the types of fishes present in a particular 

stream. Fish communities, which are species that coexist in the same stream, have the ability to complement both chemical and physical assessments by 

directly integrating water-quality effects and providing 

one of the few water-quality assessment methods that 

is sensitive to both toxicological and habitat disturbances (Cuffney and others, 1997). Gross differences 

in community structure within ecoregions are usually 

the result of localized disturbances; therefore, community level responses can be used to evaluate changing 

land-use patterns along gradients of intensity. This 

type of multidisciplinary approach is one of the basic 

components of the NAWQA Program.

Purpose and Scope

The purposes of this report are to identify the 

primary environmental characteristics that influence 

fish-community structure in the Eastern Highland Rim 

Ecoregion (EHR) of the LTEN River Basin and to 

determine if those characteristics are related to cropland density, which is the percentage of cropland in the 

contributing basin. Physical, chemical, and biological 

data were collected at 20 streams within the EHR in 

1999. Streams were selected from the EHR, rather 

than from the entire LTEN River Basin, so that natural 

physiographic and biological differences would be 

minimized and sampling efforts could be concentrated 

in the most intensively cultivated region of the LTEN 

River Basin. Results from this analysis provide a 

framework for using fish communities as indicators of 

aquatic impairment, along with specific chemical and 

physical characteristics associated with increasing 

cropland.

Description of the Eastern Highland Rim 

Ecoregion

The LTEN River Basin covers three distinct 

regions: the Coastal Plain, the Interior Low Plateau, 

and the Appalachian Plateaus Physiographic Provinces 

(fig. 1). These regions are defined by their geologic, 

topographic, and climatic similarities (Fenneman, 

1938). The Interior Low Plateau Physiographic Province is divided into sections, one of which is the Highland Rim. The Highland Rim extends west of the 

Cumberland escarpment, surrounds the Nashville 

Basin, and continues westward to the Coastal Plain 

region and is characterized by gently rolling hills, 

numerous karst features (caves, sinkholes, and 
4 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

According to Safford’s (1869) description, “If one 

could be elevated 2,000 or 3,000 feet above Nashville, 

they would see, the Highland Rim, rising up first in 

bold walls—terrace-like—all around the Basin, and 

then extending off, in every direction, in great plains.”

springs), and chert-filled streams that dissect an old 

peneplain surface. The eastern side of the Highland 

Rim, referred to as the EHR, is recognized as one of 

the five level IV ecoregions of the Interior Low Plateau Physiographic Province (Griffith and others, 

1997) (fig. 1).

The EHR makes up about 18 percent of the 

overall surface area of the LTEN River Basin (Kingsbury and others, 1999). The boundaries of the EHR 

extend southwest into Alabama, across the Tennessee 

River, and include the area between Little Mountain 

and the western escarpment of the Cumberland Plateau Ecoregion. North of the Tennessee River, the 

EHR follows an arbitrary boundary along the Elk 

River to near Winchester, Tennessee, and then north to 

the southeastern border of the Outer Nashville Basin 

and the western slope of the Cumberland Plateau 

(fig. 1). Streams in the EHR commonly flow in 

entrenched channels characterized by broad valleys, 

steep side slopes, and undercut banks. These streams 

are continuously down-cutting and in the early stages 

of flood plain and terrace development (Theis, 1936). 

Major river basins in the EHR include the Flint River, 

upper Duck River, upper and southeastern drainages of 

the Elk River, and numerous tributaries to the main 

stem of the Tennessee River. 

The climate and population of the EHR are typical of most regions in the southeastern United States. 

The climate is temperate and characterized by long, 

hot summers and short, mild winters with a mean 

annual temperature of 58 oF (National Weather Service, 2001). Total annual precipitation averages about 

57 inches per year, which is distributed evenly 

throughout the year; however, spring and summer convective storms can deliver short intensive amounts of 

rainfall resulting in flash flooding. Precipitation in the 

form of snow rarely exceeds a few inches annually. 

The population of the EHR is approximately 584,000, 

which represents approximately 38 percent of the 

overall population of the LTEN River Basin. Most of 

the population is concentrated along the Tennessee 

River in northern Alabama. Huntsville, Ala., is the 

largest city, having a population of 160,000. The EHR 

was identified as one of the fastest growing areas in 

the lower Tennessee Valley between 1980 and 1995 

(Kingsbury and others, 1999).

Physiography and Land Use

Mississippian-age carbonate rocks dominate the 

surficial geology of the EHR (Miller, 1974). These 

rocks are predominantly limestone with varying 

amounts of interbedded chert, clay, and shale. The 

most weather resistant of the Mississippian-age formations are the Fort Payne Formation and the St. Louis 

and Warsaw Limestones (based on State of Tennessee 

geologic nomenclature; refer to figure 2 for Alabama 

equivalent). Upper Mississippian-age formations are 

present along the southwestern boundaries of the 

EHR, the most prominent of which is the Hartselle 

Formation. The Hartselle Formation is easily recognized by its characteristic sandstone hills, known as 

Little Mountain (fig. 1), which are remnants where the 

surrounding area has been eroded to lower 

Mississippian-age formations. 

Mississippian-age formations are underlain by 

the Devonian and Early Mississippian-age Chattanooga Shale, a thin layer of shale that restricts vertical 

movement of ground water between the Mississippianage and the underlying Ordovician-age rocks. Ground 

water is deflected laterally, which results in numerous 

spring resurgences throughout the area. Water in these 

springs is generally sulfury as a result of elevated concentrations of iron sulfide and other minerals (Brahana 

and Bradley, 1986).

Soils across the EHR are varied. In the smooth 

upland areas of the EHR, soils have developed from 

weathered limestone, old alluvium, and silt deposits. 

Common soils include the Bodine-MountviewDickson series, and the Fullerton (Baxter) and Colbert 

types. These soils typically are well drained and moderately fertile (Springer and Elder, 1980). Along the 

eastern escarpment, soils are well drained and moderately fertile; however, cultivation is limited by the 

steep terrain and large amounts of cherty material in 

the soil. The most fertile soils are along the flood 

plains and terraces of the Tennessee River. These old 

terraces mostly are covered by several feet of loess 

and old alluvial material resulting in fertile soil well 

suited for cultivation. 

Land use in the EHR is dominated by pasture 

(41 percent) and forest (27 percent), followed by cropland (16 percent), other (10 percent), urban (3 percent), and open water (3 percent) areas (Kingsbury and 

others, 1999) (fig. 3). Although cropland represents 

only 16 percent of the land use, the EHR still ranks 

highest among the ecoregions of the LTEN River 

Basin in cropland acres per square mile. The primary 
Introduction 5

BANGOR LIMESTONE (BANGOR LIMESTONE)

HARTSELLE FORMATION (HARTSELLE SANDSTONE)

PRIDE MOUNTAIN FORMATION

PRIDE MOUNTAIN FORMATION AND MONTEAGLE LIMESTONE

MONTEAGLE LIMESTONE (INCLUDES PRIDE

MOUNTAIN FORMATION IN WESTERN PART

OF THE STUDY AREA)

ST. LOUIS AND WARSAW LIMESTONE (TUSCUMBIA LIMESTONE)

FORT PAYNE FORMATION (FORT PAYNE CHERT)

PLATEAU ESCARPMENT ECOREGION

EXPLANATION

87°41'

87°41'

86°27'

86°27'

34°58' 34°58'

35°33' 35°33'

Figure 2. Location of sampling sites, generalized geology, and suggested subgroups in the Eastern Highland Rim Ecoregion

of the lower Tennessee River Basin.

SAMPLE SITE—Site names shown

in table 1

Modified from Hardeman, 1966; Osborne and others, 1989

TENNESSEE GEOLOGIC NOMENCLATURE (ALABAMA EQUIVALENT)

BARRENS

DISSECTED TABLELANDS

MOULTON VALLEY

EXPLANATION

SUGGESTED SUBGROUPS WITHIN THE

EASTERN HIGHLAND RIM ECOREGION

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

Elk River

17

20

18 19 16

14

13

10

12

11

6

15

7

8

9

5

4

1

2

3
6 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

EXPLANATION

PASTURE

CROPLAND

URBAN

FOREST

WETLAND

OPEN WATER

Ala.

Tenn.

Figure 3. Land use in the Eastern Highland Rim Ecoregion of the lower Tennessee River Basin.

Land-use and land-cover digital data provided by TVA (Frank Sagona, Tennessee

Valley Authority, written commun., 1998). Land-cover data were derived spectrally

from satellite imagery (from period 1989-92), and ground truthed using infrared

aerial photography. Boundaries for certain land-use classifications (urban and

wetland areas) were digitized from topographic maps

10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

0

row crops are cotton, corn, soybeans, and wheat. Pastureland is used for animal grazing, hay production, 

commercial nurseries, and confined animal feeding 

operations. 

The Barrens (fig. 2) is a geologically unique 

area located along the northeastern boundary of the 

EHR. The name was first applied by the early settlers 

for its prairie-like landscapes. This area is characterized by flat karst topography and soils that are highly 

leached, acidic, and low in fertility. Vegetation is 

present that represents the northern Appalachians, the 

south Atlantic and Gulf Coastal Plains, and the northern prairies (Springer and Elder, 1980). The area is 

underlain by limestones, shales, and cherts of the Warsaw Limestone and Fort Payne Formation (Wolfe and 

others, 1997). Weakly dissected uplands with low 

relief, intermittent streams, and perennially wet, shallow pans also are characteristic of this area. The Barrens, which were once covered by warm season 

grasses, such as switch grass, Indian grass, and little 

bluestem, are now dominated by dense oak thickets.

Another unique area is the Moulton Valley, 

which is located along the southern margin of the EHR 

(fig. 2). The Moulton Valley is located between the 

western slope of the Cumberland Plateau Ecoregion 

and its intersection with the Coastal Plain Physiographic Province (figs. 1 and 2). This area is characterized by broad flat uplands, sandstone-capped ridges, 

and gently sloping broad valleys derived from old 

alluvial deposits. The isolated sandstone hills (Little 

Mountain) and steep slopes are remnants of the adjacent Cumberland Plateau. The weakly developed 

drainage pattern in the Moulton Valley includes a few 

permanent streams, however, most are intermittent. 

Most of the Moulton Valley is covered by forest in an 

area that was once heavily influenced by cultivation 

and livestock grazing.

The remaining area of the EHR consists of the 

Dissected Tablelands, which cover most of the EHR 

from the southern boundary of the Barrens to the Tennessee River (fig. 2). The terrain is flat with scattered 

limestone knobs and hills along its eastern boundary. 
Introduction 7

The Dissected Tablelands are underlain by the St. 

Louis and Warsaw Limestones. These limestones produce extensive cave and sinkhole systems throughout 

the area (Theis, 1936). The Dissected Tablelands 

include some of the most fertile soils in the EHR. The 

deep, red, loamy soils found along the lower Elk and 

Tennessee Rivers are farmed extensively. Most 

streams are perennial and flow southward in broad, 

shallow depressions, with low relief. 

Fauna and Flora

Along with diverse landscapes and karst features, the EHR also is known for its unique fauna and 

flora (Etnier and Starnes, 1993; DeSelm, 1994). Having more than 100 native fish species, the EHR ranks 

as one of the most biologically diverse regions in 

North America (Etnier and Starnes, 1993; Mettee and 

others, 1996). The U.S. Fish and Wildlife Service currently (2002) lists two fish species in the EHR as being 

threatened or endangered—the slackwater darter 

(Etheostoma boschungi, threatened) and the Alabama 

cavefish (Speoplatyrhinus poulsoni, endangered). An 

additional seven species are considered rare throughout their range and likely will be considered candidate 

species in the future—ashy darter (Etheostoma 

cinereum), barrens topminnow (Fundulus julisia), 

Tuscumbia darter (Etheostoma tuscumbia), blotched 

chub (Erimystax insignis), flame chub (Hemitremia 

flammea), spring pygmy sunfish (Ellasoma alabamae), and southern cavefish (Typhlichthys subterraneus) (Etnier and Starnes, 1993; U.S. Fish and 

Wildlife Service, 2001). Two species are presumed 

extinct—the harelip sucker (Lagochila lacera) and the 

whiteline topminnow (Fundulus albolineatus) (Miller 

and others, 1989). The diversity of terrestrial plants is 

equally impressive; more than 1,000 species and varieties are present in the Barrens subregion alone 

(DeSelm, 1994), which composes over 39 percent of 

Tennessee’s total vascular flora (Wofford and Kral, 

1997). All common and scientific names follow 

nomenclature in Robins and others (1991).

The first recorded ichthyological surveys were 

conducted in the Tennessee River in the mid-1800s. 

Dr. D.H. Stoner reported at an 1845 meeting of the 

Boston Society of Natural History on nine species he 

had collected from the Tennessee River near Florence, 

Ala. (Agassiz, 1854). A few years later, Dr. Louis 

Agassiz reported on approximately 30 species from 

the same area (Agassiz, 1854). Until the mid-1800s, 

little was known about the diversity of fishes present 

in the Tennessee River and its tributaries. It also is 

interesting to note that Agassiz was already postulating ideas on how elevation and climate might influence fish distributions in the Tennessee River. In his 

closing remarks Dr. Agassiz stated, “The day is not far 

distant when we shall know with sufficient precision 

where all the living beings now existing upon the earth 

have made their first appearance.” Today (2002) ichthyologists have documented between 205 and 215 

native fishes from the Tennessee River system (Etnier 

and Starnes, 1993). 

Flame Chub (Hemitrema flammea), State Rank—In

need of Management. The flame chub typically is

associated with springs; however, it is not restricted to

springs. The greatest threats to the flame chub are

alteration of spring habitats, increased sediment loads,

and denuding of streambanks (Armstrong and Williams,

1971). (Photograph by M.D. Woodside, U.S. Geological

Survey.)

Barrens topminnow (Fundulus julisia), State Rank—

Threatened. The barrens topminnow is a Highland Rim

endemic. This small topminnow prefers spring-like habitats that are heavily vegetated with plants such as

watercress and filamentous algae (Etnier and Starnes,

1993). Once widely distributed in the upper Duck and

Elk Rivers, recent surveys indicate that only isolated

populations currently exist and may be extirpated from

the Duck River altogether. Potential threats include

alteration of springs and sedimentation. (Photograph

by J.R. Shute, Conservation Fisheries, Inc. Used with

permission.)
8 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

By the mid-1930s, the introduction of "super-phosphate"

fertilizers were highly touted at a crop-enhancement

technique that boosted crop yields and minimized soil

erosion. (Photos from Tennessee Valley Authority Historic

Collection. Used with permission.)

Since the turn of the 20th Century, many 

researchers and institutions have contributed to the 

identification and biogeography of fishes in the Tennessee River and the EHR. However, not until the 

1980s were fish communities used as biological indicators of water quality in Tennessee Valley streams 

(Saylor and others, 1988; Saylor and Ahlstedt, 1996). 

The Tennessee Valley Authority (TVA) was one of the 

first Federal agencies in the Southeast to take a proactive approach in performing biological assessments at 

a watershed scale. These TVA studies were based on 

methods initially developed for streams in the Midwest by Karr (1981), where the primary objective was 

to assess the health of the stream using an Index of 

Biological Integrity (IBI). The IBI provides a numeric 

representation that can be used by managers and policy makers in making environmental decisions. 

Historical Land Use

Naturally occurring (lightning) and humaninduced fires have significantly altered the landscape 

in parts of the EHR for hundreds of years (DeSelm, 

1994). Native Americans recognized the benefits of 

using fire to clear lands for grazing and also to stimulate plant growth. Many of the fires induced by Native 

Americans were believed to have occurred in the fall, 

during the driest season, hence the term “Indian Summer” (McClain, 2000). The first European settlers also 

recognized the usefulness of fire, but for different reasons. Milo Pyne (Nature Conservancy, written commun., 2000) suggests that the European settlers started 

fires in the spring, in hopes of combating and discouraging the Native Americans from burning their farmland. Fewer fires were started as more settlers moved 

into the area, thus again resulting in further landscape 

changes. 

Agriculture has been and continues to be a 

major influence in the EHR. Along the fertile bottoms 

and terraces of the larger rivers, corn and cotton continue to be the staple row crops. Although lands along 

the river bottoms were intensively cultivated in the 

1800s, pasture was by far the most dominant land use 

in the EHR (Killebrew and Safford, 1874). Along the 

rocky hillsides, which typically have shallow soils, 

hay production and cattle grazing dominated the landscape. According to one farmer, “Our soils are better 

adapted to the raising of grasses than any other crop, 

while it necessary in the States north of us to manure 

their meadows in order to ensure a good hay crop, I 

have never known one to be manured in this county, 

except from the droppings of stock. The grass grows 

profusely without any top dressing.” By the early 

1900s, scientists had already witnessed the effects of 

careless agricultural practices. Programs that highlighted soil-loss prevention and control of water pollution were soon implemented to educate the farming 

community; however, the attitude of most farmers of 

this era was that it was cheaper to clear new fields than 

to pay close attention to fertilizing and cultivating previously cleared fields. Farmers were warned about the 

economic losses they would incur from extensive soil 

erosion resulting from shallow plowing. 

Protecting drinking-water supplies against 

agricultural-induced contamination became an important issue in the early 1900s. Occasional outbreaks of 

cholera, typhoid fever, and other enteric illnesses 

helped to maintain awareness of water quality (Switzer, 1914). Fuller (1910) emphasized the farmer’s need 

to protect streams, wells, sinkholes, and springs from 

potential contamination. Although maintaining aquatic 
Introduction 9

The farming community was already acknowledging

water-quality concerns by the turn of the 20th Century.

Concerns were primarily related to drinking-water

supplies; however, other issues included preventing

eutrophication of farm ponds and livestock water

sources. (Photos from Fuller, 1910.)

biodiversity was not the major concern for water quality in the early 1900s, the protection of biodiversity 

was an unintended outcome of the resource management practices promoted by scientists of this period. 

The same soil and water issues present at the 

turn of the 20th Century in the EHR still exist today, 

although the amount of land under cultivation has continually decreased since the 1950s, and watersheds 

that were once cultivated and trampled by cattle are 

now covered by forest (U.S. Geological Survey, 2000). 

Harding and others (1998) report that some streams in 

the upper Tennessee River Basin, after years of flowing through farmlands, were ecologically impaired due 

to sedimentation from 50 years earlier. They concluded that the best predictor of present-day diversity 

of fishes could be land-use information from the 

1950s. The ability to recognize and use past failures 

and successes will enhance the ability to monitor and 

protect aquatic resources in the future, while failing to 

consider past land-use patterns could result in biased 

and misleading results about how different present 

land-use practices affect water quality and biodiversity.

Acknowledgments

The author would like to thank Amy Wales, 

Charlie Saylor, Dave Mathews, Kenny Gardner, and 

Mark Odom (Tennessee Valley Authority) for providing taxonomic assistance and data management skills 

that were invaluable, and David Etnier (University of 

Tennessee) who validated and vouchered most of the 

Safford (1869) describes landscape changes in the Barrens: “It was a custom with the early settlers to burn off 

these lands every spring, in order that the barren grass, a strong, coarse, but nutritious herbage, might spring up 

and supply summer grazing for the cattle....There were but few trees, and those of an inferior kind of timber, being 

scrubby black jack, which, owing to the thickness of the bark, is able to resist the prairie fires. There was no 

undergrowth, and the strawberry vines laden with fruit in the spring filled the air with delightful odor. The wild 

honeysuckle, lady slipper, and wild pink contributed their fragrance and their flowers to the landscape. The soil, 

however, was poor. A cold, clammy, whitish soil, with here and there a marshy spot covered with large water oaks, 

which were protected from the fire by the character of their place of growth, was characteristic of the land in winter. A few settlers built houses along the margins of the wet weather streams and cleared a few acres. In order to 

protect their fences, fires were interdicted. A rank undergrowth of gum, hazel, hickory, and red oak sprung up. Red 

oaks, post oaks, and hickories shot up into the upper air. Several generations of leaves fell to the earth and rotted. 

The soil blackened....A good drainage supervened. Marshy places dried up, and the land became productive....Thirty years ago a cow or horse could be seen for miles, there being no undergrowth or timber to obstruct 

the view. It is impossible now to ride on horseback through the woods. Impenetrable thickets have sprung up, and 

all the features which distinguished the landscape thirty years ago, nearly all the characteristics of the country at 

that time, have disappeared.”
10 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

collection. The author also would like to thank the 

many individuals from the USGS who assisted with 

field sampling, including Mike Woodside, Jerry Garrett, Anne Hoos, Rodney Knight, Jim Kingsbury, John 

Robinson, Reavis Mitchell, John Shelton, David Butner, and Randall Kidwell (student intern) for their tireless efforts throughout the project. Tom Cuffney, Anne 

Hoos, Pete Ruhl, and Wade Bryant provided thoughtful reviews.

STUDY DESIGN

A gradient approach was used to evaluate the 

response of fish communities to changes in water 

chemistry and physical characteristics associated with 

varying degrees (gradient) of cropland. Interpretations 

from a gradient study of multiple watersheds can be 

transferred to the management problem of predicting 

how water chemistry will respond in a single watershed, considering changes in cropland percentages 

over time. By studying changes in water chemistry, 

habitat, hydrology, and fish communities, State and 

regional managers may predict with some degree of 

accuracy the effects of changing cropland allotments. 

This type of approach also can help managers decide 

on the appropriate cropland percentage at which they 

can most effectively meet, or achieve, designated 

water-quality standards.

While some degree of natural variability is 

expected within the EHR, ecoregion boundaries are 

delineated so that the natural variability within an 

ecoregion is relatively small (for example, compared 

with variability associated with human influence on 

the landscape). To further minimize natural variability, 

sites were selected from the same environmental setting by using the following criteria: (1) sites represented a range of 1 to 30 percent in cropland density; 

(2) sites had drainage basins ranging from about 30 to 

100 square miles (mi2

); (3) the entire basin was within 

the EHR; (4) streams were third order or less; (5) urban 

areas were less than 4 percent in the contributing drainage area; and (6) streams were wadable. Selected sites 

were located far enough upstream of any major river or 

reservoir to minimize the influence of big-river or 

reservoir-type fishes (species that make seasonal 

spawning runs in the smaller streams). Based on these 

criteria, 20 streams were selected within the EHR and 

sampled during spring 1999 (table 1 and fig. 2). 

SAMPLING METHODS

A variety of methods were used in this study, 

but all are based on a spatial hierarchy (basin, segment, and reach) as described by Fitzpatrick and others (1998). The reach, which is the principal unit at 

which physical, chemical, and biological field collections were made, was selected on the basis of a variety 

of instream channel features, such as distribution of 

geomorphic channel units (runs, riffles, and pools), 

wadability, width, and the absence of local disturbance 

or other discontinuous features within the identified 

stream. Generally, the length of the reach was determined by multiplying the average stream width by 20. 

The average reach length for streams sampled in the 

EHR was 656 feet. All field sampling activities were 

conducted between May and July 1999. 

Environmental Characteristics

Physical characteristics consist of a combined 

set of habitat, hydrology, and land-use (HHL) variables. Habitat variables (table 2) were measured along 

11 equidistant transects located within the sampling 

reach as described by Fitzpatrick and others (1998). 

Measurements of depth, velocity, dominant substrate, 

and percentage of substrate embeddedness were made 

at three instream points; bank angle, bank substrate, 

percentage of vegetative cover, and percentage of erosion were measured at each stream bank. Dominant 

substrate was determined by particle-size classes, and 

substrate embeddedness percentages were visually 

estimated in increments of 10. Bank angle, streambank vegetation, bank height, and bank substrate measurements were combined into a bank stability index 

prior to analysis (Fitzpatrick and Giddings, 1997). 

Riparian zones were characterized by canopy angle 

and canopy closure measurements. Canopy angles 

were measured by using a clinometer from the thalweg 

of the channel for left and right banks. An open canopy angle was then calculated by adding the two 

angles and dividing by 180 degrees. Canopy closure 

was measured at the water’s edge with a concave 

spherical densiometer. The measurements from each 

transect were then summed and reported as a canopy 

cover percentage for the reach. 

Hydrologic data collection consisted of an 

instantaneous streamflow measurement and an estimate of low flow. An instantaneous discharge measurement was collected once at each site in 
Sampling Methods 11

Table 1. Basin characteristics of sampling sites for fish community, water chemistry, and physical habitat in the Eastern Highland Rim 

Tennessee River Basin

[NAVD 88, North American Vertical Datum of 1988; <, less than]

Site 

number 

(fig. 2) Site name

Site 

abbreviation

Station 

identification number

Drainage 

area, in 

square 

miles

Elevation, in 

feet above 

NAVD 88

Pasture

Barrens

1 Bradley Creek near Prairie Plains, Tenn. Bradley 03578502 45.1 970 50 2 Crumpton Creek at Rutledge Falls, Tenn. Crumpton 03596100 27.3 880 35 3 Little Duck River at Grindstone Hollow at 

Manchester, Tenn. LitDuck 03595700 41.2 970 38 

4 Rock Creek near Tullahoma, Tenn. Rock 03579680 36.2 920 51 

Dissected Tablelands

5 Beans Creek at Brown Mill, Tenn. Beans 03580787 48.5 820 45 6 Beaverdam Creek near Meridianville, Ala. Bdam 03574870 37.2 705 39 7 Brier Fork near Hazel Green, Ala. BrierF 03574823 40.8 740 56 8 Flint River at Lincoln, Tenn. FlintLin 03574702 52.1 780 59 9 Hester Creek at Buddy Williamson Road near 

Plevna, Ala. Hester 0357479650 29.3 760 50 

10 Indian Creek near Madison, Ala. Indian 03575830 48.6 610 36 11 Limestone Creek near Toney, Ala. Lime 03576207 27.8 770 55 12 Little Limestone Creek near Toney, Ala. LitLim 03576226 33.8 740 66 13 Piney Creek near Athens, Ala. Piney 03576405 60.7 650 61 14 Round Island Creek near Lawson, Ala. RndIs 03577490 34.0 585 52 15 West Fork Flint River near Hazel Green, Ala. Wfork 03574750 39.6 750 56 

Moulton Valley

16 Clear Fork below Masterson, Ala. ClearFk 03586400 27.3 570 52 17 Little Bear Creek near Tuscumbia, Ala. LitBear 03590550 50.9 430 29 18 Mud Creek near Old Bethel, Ala. Mud 03587378 48.4 560 46 19 Muddy Fork near Moulton, Ala. Muddy 03586240 71.3 560 55 20 Spring Creek near Tuscumbia, Ala. Spring 03590450 97.7 420 31 
12 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

conjunction with the water sample. Depth and velocity 

were measured using a wading rod and pygmy meter 

according to procedures outlined in Buchanan and 

Somers (1969). Low-flow characteristics were estimated and used as a means of accounting for groundwater availability to streams during dry weather. The 

low-flow characteristics were estimated by using 

regression equations with the explanatory variables 

drainage area, annual precipitation, and mapped 

streamflow recession index. The low-flow characteristic used in this analysis was the lowest 7-day average 

discharge with a recurrence interval of 10 years as 

described by Bingham (1986) and Atkins and Pearman 

(1995). 

Land-use and land-cover digital data were provided by the TVA (Frank Sagona, Tennessee Valley 

Authority, written commun., 1998). Boundaries for 

land-use classifications and individual drainage areas 

were delineated from 1:24,000 USGS topographic 

maps. Estimates of beef cattle density were obtained 

from the Watershed Characterization System (1999) 

(U.S. Environmental Protection Agency, 2000); calculations were based on watershed boundary and countywide animal census data.

Water samples for chemical analysis were collected once at each site during normal springtime 

flows, when streamflow was stable, safely wadable, 

and was not affected by runoff from recent rainfall. 

Samples were collected by using depth- and widthintegrating procedures as described by Shelton (1994) 

and analyzed for pH, dissolved oxygen, specific conductivity, fecal-indicator bacteria (Escherichia coli) 

Table 2. Habitat, hydrology, and land-use variables used to characterize sites in the Eastern Highland 

Rim Ecoregion of the lower Tennessee River Basin 

[m, meter; ft, foot; NAVD 88, North American Vertical Datum of 1988; mi2, square mile; 7Q10, 7-day 10-year average 

discharge; ft3

/s, cubic foot per second]

Type Habitat, hydrology, and land-use variable (units) Abbreviation

Habitat Segment sinuosity (ratio) sinuosity

Reach gradient (no unit) gradient

Reach as run habitat (percent) run

Reach as riffle habitat (percent) riffle

Reach as pool habitat (percent) pool

Average wetted channel width (m) WCwidth

Average bankfull width (m) BFwidth

Substrate as cobble (percent) cobble

Substrate as sand (percent) sand

Substrate as gravel (percent) gravel

Substrate as bedrock (percent) BR

Bank Stability Index (dimensionless) BSI

Open canopy (percent) opencanopy

Average depth (ft) depth

Substrate embeddedness (percent) embedded

Elevation at reach (ft above NAVD 88) elevation

Contributing drainage area (mi2) DA

Hydrology Low-flow characteristic, 7Q10 (ft3

/s) LowBaseQ

Instantaneous streamflow (ft3/s) Q

Land use Contributing basin in pastureland, 1992 (percent) pasture

Contributing basin in cultivated land, 1992 (percent) cropland

Contributing basin forested, 1992 (percent) forest

Contributing basin as forested wetlands, 1992 (percent) forwetland

Number of beef cows sold per year, 1997 beefcow

Cows per acre of pasture, 1997 (head per acre) cowacre
Sampling Methods 13

and water temperature in the field. Nutrients (various 

forms of nitrogen and phosphorus), dissolved- and 

total-organic carbon, and major inorganic constituents 

(table 3) were analyzed at the USGS National Water 

Quality Laboratory (NWQL) in Lakewood, Colo. 

Fish Communities

Fish were collected from each stream once 

between May and June 1999 by using procedures 

described by Meador and others (1993). Reaches were 

sampled by using a towed barge or backpack electroshocker and seine (6- by 15-foot by 3

/16-inch 

mesh). Each reach was fished once using a zigzag pattern. Following collection, all specimens were immediately identified, counted, observed for external 

lesions or deformities, and released downstream of the 

sample reach. Game fish (Centrarchids) were measured and weighed prior to releasing. All specimens 

were identified by the author and either by Amy B. 

Wales or Charles F. Saylor (aquatic biologists, TVA). 

Voucher specimens from each site, excluding threatened and endangered species, were preserved in a 

Table 3. Water-chemistry variables used to characterize sites in the Eastern Highland 

Rim Ecoregion of the lower Tennessee River Basin

[

o

C, degrees Celsius; μS/cm at 25 oC, microseimens per centimeter at 25 degrees Celsius; mg/L, 

milligrams per liter; μg/L, micrograms per liter; NTU, nephelometric turbidity units; col./100 mL, 

number of Escherichia coli colonies per 100 milliliters of sample water; N, nitrogen; P, phosphorus]

Water-chemistry variable (units) Abbreviation

Water temperature (oC) temp

pH pH

Specific conductivity (μS/cm at 25 o

C) spcond

Alkalinity (mg/L) alk

Ammonia, dissolved (mg/L as N) NH4

Nitrite, dissolved (mg/L as N) NO2

Ammonia plus organic nitrogen, dissolved (mg/L as N) NH4dis

Ammonia plus organic total nitrogen (mg/L as N) NH4total

Nitrite plus nitrate, dissolved (mg/L as N) NO2NO3

Total phosphorus (mg/L as P) P

Phosphorus, dissolved (mg/L as P) Pdis

Ortho-phosphorus, dissolved (mg/L as P) Portho

Total organic carbon (mg/L) TOC

Dissolved organic carbon (mg/L) DOC

Total nitrogen (mg/L) N

Turbidity (NTU) turbid

Escherichia coli (col./100 mL) EC

Calcium, dissolved (mg/L) CA

Silica, dissolved (mg/L) SIO2

Iron, dissolved (μg/L) FE

Potassium, dissolved (mg/L) K

Sodium, dissolved (mg/L) NA

Chloride, dissolved (mg/L) CL

Magnesium, dissolved (mg/L) MG

Fluoride, dissolved (mg/L) F

Manganese, dissolved (mg/L) MN

Sulfate, dissolved (mg/L) SO4
14 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

A variety of sampling methods and techniques were used to collect fish. Seining is an effective technique for

sampling in debris-free pools and backwater eddies. Seining also limits the stress induced by electrofishing.

Riffles and fast flowing sections were sampled by electrofishing into a seine that was placed perpendicular

to the flow and downstream of the electrofishing unit. (Photographs by R.R. Knight, U.S. Geological Survey.)
Analytical Methods 15

10-percent formalin solution and archived in the University of Tennessee Research Collection of Fishes 

(University of Tennessee, Knoxville) and in the University of Alabama Ichthyological Collection. 

ANALYTICAL METHODS

Responses of fish communities to cropland density and natural environmental setting were determined by (1) identifying the chemical and physical 

characteristics that explain most of the variability 

among sites, (2) determining whether those characteristics were associated with cropland density or were 

caused by natural environmental variability, and 

(3) identifying which environmental characteristics 

influenced fish-community structure. Three data sets 

were used to describe 20 sites in the EHR—fishcommunity (response variable), water-chemistry 

(chemical environmental variables), and combined 

data set of HHL characteristics (physical environmental variables). Two ordination procedures, principal 

components analysis (PCA) and correspondence analysis (CA), were used to describe patterns in the data. 

PCA was used for exploratory data analysis to identify 

the most important environmental variables related to 

natural setting and cropland density; CA and PCA 

were used to summarize fish communities (abundance 

and metrics, respectively); and an indirect gradient 

analysis was used to determine the response of fish 

communities (CA and PCA) to cropland density and 

natural environmental variability. In addition, an IBI 

was used to determine and compare fish-community 

response to cropland density, natural environmental 

variability, and results from the CA and PCA.

Environmental Characteristics

Environmental data were analyzed separately 

using ordination of PCA, which was initially used for 

exploratory data analysis to identify the most important variables within each data set. PCA identifies axes 

(gradients) that are linear combinations of the original 

variables. The first PCA axis explains most of the variance, and each successive axis accounts for a decreasing amount of the remaining variance. Individual 

variables along an axis are expressed as variable loadings to indicate relative importance. These variable 

loadings can be used to identify the most important 

variables associated with each axis. An arrow represents each environmental variable where the arrow’s 

length is an indication of the relative importance of the 

variable to the axis; for example, long arrows are more 

important than short arrows. 

PCA also was used for indirect gradient analysis 

to relate the most important gradients, usually the first 

two or three axes, to cropland density and natural environmental setting. Site scores (also called eigenvectors) for selected axes were correlated with cropland 

density to determine whether the PCA gradients were 

associated with natural environmental characteristics 

or cropland density. Site scores are coordinates along 

an axis specifying the location of sites along the environmental gradient. Sites having similar characteristics, or scores, cluster together, and sites having 

dissimilar characteristics are located farther apart. 

Prior to running the PCA, all data were standardized to 

a mean of 0 and standard deviation of 1. PCA was performed using the computer program Multivariate Statistical Package (Kovach, 1998).

Fish Communities

Fish communities were summarized and analyzed separately by using (1) CA, which is based on 

species abundance; (2) PCA, which is based on individual community metrics; and (3) IBI, which is based 

on a combined set of community metrics. CA and 

PCA are considered ordination procedures; however, 

PCA assumes a linear response, whereas CA assumes 

a unimodal, or bell-shaped, response. The unimodal 

response model is important because fish abundance 

rarely responds linearly to environmental changes. 

Every fish species, for example, adapts to its own optimal range of environmental conditions, such as pH, 

dissolved oxygen, or temperature, and conditions outside this range will result in a decrease in abundance 

of the species. Relative abundance values used in the 

CA were arcsin transformed (Zar, 1999), and rare species were downweighted prior to analysis. This transformation prevents extremely abundant or extremely 

rare values from having undue influence on the analysis (Gauch, 1982). Although non-native and big-river 

species were rarely collected, all data for these species 

were removed prior to analysis to minimize undue 

bias. CA was performed using the Multivariate Statistical Package (Kovach, 1998). 

PCA was used to analyze 14 community metrics 

that are presumed indicators of anthropogenic disturbance (table 4). PCA was used rather than CA because 

metrics tend to respond to environmental changes 
16 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Table 4. Fish-community metrics used to summarize groups of fishes in the Eastern Highland Rim Ecoregion

[Refer to Appendix 4 for species classifications; LTEN, lower Tennessee; DELTs, deformities, lesions, and tumors]

Fish-community 

metric

(abbreviation)

Description and rationale for use

Number of darter 

species (darters)

Darters are benthic dwelling fishes, therefore, they tend to be sensitive to many forms of anthropogenic perturbations, such as channelization, siltation, and reduced dissolved oxygen levels (Karr and others, 1986).

Percentage of individuals as specialized insectivores 

(spinsect)

Specialized insectivores compose the largest trophic class of fishes in the LTEN River Basin. A decrease in 

percentage typically is related to a decline in the insect community, which in turn may reflect degrading 

water-quality and instream habitat conditions (Karr and others, 1986).

Number of native 

species (natives)

The number of native species metric is based on the premise that the number of native species will decline 

with increased environmental disturbance (Karr and others, 1986). The exclusion from the metric of all 

non-native species provides a more accurate asssessment of overall biotic integrity.

Number of sunfish 

species (sunfish)

Sunfish species are sensitive to degradation of pool habitat (Ohio Environmental Protection Agency, 1987).

Percentage of individuals as simple 

lithophilic spawners (simLiths)

The term simple lithophils refers to the spawning behavior of fishes that broadcast their eggs across cobbleand gravel-sized substrates where eggs are left to develop in the interstitial spaces (Simon, 1999). Simple 

lithophils require clean gravel and cobble to successfully reproduce. The negative relation between percentage of simple lithophils and degree of siltation was documented by Berkman and Rabeni (1987).

Percentage of individuals as 

omnivores and 

stonerollers 

(omnivores)

This metric has been modified to include stonerollers (Campostoma oligolepis) and represents fishes commonly classified as “opportunist” and “generalist.” The stoneroller is a grazing minnow that uses the cartilagenous ridge located below the jaw to scrape and feed on algae and detritus (Jenkins and Burkhead, 

1993). Stonerollers feed in schools and have been known to significantly alter algal community composition and distributions (Power and Mathews, 1983).

Percentage of individuals with 

external anomalies (anomalies)

External anomalies include tumors, lesions, fin damage, skeletal deformities, or any other indication of 

external damage. Black spot was included in the metric. Studies indicate that the percentage of individuals with external anomalies increase at degraded sites, particularly downstream of municipal and industrial wastewater discharges (Ohio Environmental Protection Agency, 1987).

Catch rate 

(catchrate)

Catch rate is synonymous with the number of individuals in a given sample. Catch rate is expressed in this 

report as the number of individuals collected per 300 square feet. Catch rate generally decreases as waterquality and habitat conditions deteriorate; however, catch rate can actually increase in streams that are 

artifically enriched with nutrients (Barbour and others, 1999).

Number of sucker 

species (suckers)

Similar to sunfish, suckers are most sensitive to degradation of overall habitat conditions. Because of their 

longevity, suckers also are good indicators of past conditions (some sucker species can live up to 

20 years) (Karr and others, 1986).

Number of intolerant 

species (intols)

Intolerant species are those for which abundances decrease due to anthropogenic impacts. Karr and others 

(1986) suggest that increase in siltation is the primary factor associated with a decrease in the number of 

intolerant species.

Percentage of individuals as tolerant species 

(tolerant)

Tolerant species typically become the dominant species in severely degraded streams (Ohio Environmental 

Protection Agency, 1987).

Percentage of individuals as hybrids 

(hybrid)

The hybrid metric is an estimate of the reproductive capacity of the habitat (Ohio Environmental Protection 

Agency, 1987). It is often substituted for the simple lithophils metric, reflecting the opposite conditions. 

For example, the percentage of hybrids increases as spawning conditions degrade.

Percentage of individuals as piscivores (pisc)The piscivore metric is designed to reflect fish that feed, as adults, on other fish and crayfish (Ohio Environmental Protection Agency, 1987). Goldstein and Simon (1999) discuss the piscivore group in greater 

detail by using terms for types of feeding strategies, such as “stalkers,” “chasers,” “ambushers,” and fish 

that have a “protective resemblance” to their environment. 

Percentage of individuals with 

DELTs (DELT)

Similar to the percentage of individuals with external anomalies metric, the DELT metric includes all external anomalies minus black spot. Black spot and some other parasites may be present on individuals and 

not linked to factors associated with poor water quality.
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 17

linearly rather than unimodally. Community metrics 

are a convenient way of grouping fish taxa based on 

shared ecological or taxonomic characteristics. Metrics are used to simplify complex multivariate data in 

such a way that a change in one or more of the metric 

values is indicative of some level of perturbation. Each 

metric is designed to change in a predictable way that 

reflects some change in the environment (Barbour and 

others, 1999). Individual metrics were selected on the 

basis of their potential to respond to anthropogenic 

disturbance in a predictive way. Prior to running the 

PCA, observed values were standardized to a mean of 

0 and standard deviation of 1 to facilitate comparisons 

involving multiple units of measurement. 

The IBI, an integrated index based on 12 of the 

14 metrics used in the PCA, also was calculated for 

each site. The 12 metrics used in the IBI calculation 

were selected because of their usage by other agencies. 

Criteria for IBI calculation were developed by the 

TVA and are used for similar size streams located 

within the Interior Low Plateau Physiographic Province. The IBI provides a more holistic approach to 

fish-community assessment, while the analysis of individual metrics allows comparisons of specific aspects 

of the community.

Response of Fish Communities to Cropland 

Density and Environmental Characteristics

Indirect gradient analysis was used to relate 

fish-community characteristics and environmental 

variables related to natural setting and the a priori

cropland-density gradient. The IBI additionally was 

used as a procedure to determine whether a multimetric index is influenced by natural environmental setting and cropland density and to compare the 

sensitivity of an integrated index to the results of CA. 

Spearman-rank correlation analysis was performed on 

the combined data set creating a matrix of correlation 

coefficients (Spearman’s rho). Correlations were evaluated by generating simple scatter plots and were individually tested for significance (judged significant 

when p<0.05) by using S-Plus statistical software 

(MathSoft, 1999). 

ENVIRONMENTAL CHARACTERISTICS 

AND FISH COMMUNITIES IN THE 

EASTERN HIGHLAND RIM ECOREGION

Environmental and fish-community characteristics were summarized for 20 sites in the EHR in 1999. 

The following section presents results from the ordination of the environmental and fish-community data, 

identification of environmental characteristics associated with cropland density and natural setting, and 

response of fish communities to cropland densities and 

natural environmental setting.

Physical Characteristics

A total of 25 HHL variables were measured at 

sites in the EHR. Pasture (ranging from 29 to 66 percent, table 1) and forest (ranging from 23 to 69 percent) were the predominant land uses, mixed with a 

gradient of cropland densities (ranging from 1 to 

30 percent). Elevations ranged from 420 feet above 

NAVD 88 at Spring Creek near the southern boundary 

to 970 feet above NAVD 88 at Bradley Creek and Little Duck River near the northern boundary of the EHR. 

The areas of the contributing basins, which can dramatically influence fish distributions, ranged from 

27.3 to 97.7 mi2. Instantaneous streamflow measurements (Q) ranged from 5.3 to 113 cubic feet per second (ft3

/s) at Clear Fork and Bradley Creek, 

respectively, and low-flow estimates (LowBaseQ) 

ranged from 0.04 to 13 ft3

/s.

Results from the ordination of the HHL data 

indicate that the dominant gradients are related to variability in natural setting more than to variability associated with anthropogenic disturbance. The most 

important variables along the first axis (based on variable loadings) were elevation (elevation), streamflow 

(LowBaseQ), and other intercorrelated variables, such 

as reach-gradient (gradient) and instream habitat characteristics (pool, embedded, opencanopy, depth, and 

WCwidth) (table 5; fig. 4). Sites 3, 1, 5, and 8 at the 

upper end of the elevation gradient also had wider 

channels (BFwidth), increased streamflow (Q and 

LowBaseQ), higher percentages of pasture (pasture), 

and increased reach-gradient (gradient) than sites 17, 

20, 19, and 6 at the lower end of the gradient, which 

had increased pool habitat (pool), substrate embeddedness (embedded), and deeper channels (depth) (fig. 4). 

The primary variables along the second axis are 

related to instream conditions, such as wetted channel 

width (WCwidth), substrate size (cobble and gravel), 

and flow (Q). The third axis was related to streamflow 

(Q and LowBaseQ), channel depth (depth), and percentage of the basin in vegetated wetlands (forwetland), indicating that basins with increased streamflow 

(Q and LowBaseQ) also have less vegetated wetlands 
18 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Table 5. Summary statistics from the principal components analysis of the habitat, 

hydrology, and land-use variables for 20 sites in the Eastern Highland Rim Ecoregion

[Variable abbreviations are listed in table 2; bolded variable loadings were considered important when 

absolute values were 0.2 or greater; HHL, habitat, hydrology, and land use]

HHL variable

Variable loadings

Axis 1 Axis 2 Axis 3

beefcow 0.03 0.09 -0.19

DA 0.20 -0.14 -0.16

Q -0.21 -0.36 0.23

LowBaseQ -0.20 -0.05 0.46

cropland -0.01 -0.18 0.19

pasture -0.18 0.23 0.01

forest 0.14 -0.21 0.02

forwetland -0.02 0.18 -0.36

elevation -0.35 -0.16 0.20

sinuosity 0.05 -0.17 0.18

gradient -0.22 0.27 0.20

run -0.28 -0.16 -0.25

pool 0.34 0.03 0.11

WCwidth -0.22 -0.41 -0.10

BFwidth -0.21 0.08 -0.14

BSI 0.19 -0.23 -0.02

opencanopy -0.20 -0.21 -0.06

depth 0.20 -0.20 0.30

embedded 0.34 0.05 0.21

BR -0.23 -0.09 -0.15

cobble -0.03 0.33 0.33

gravel 0.24 -0.26 -0.17

sand 0.17 -0.14 -0.05

cowacre 0.02 -0.15 -0.28

Eigenvalues 5.25 3.33 2.63

Percentage of variability in 

data set explained by axis.

22.84 14.49 11.43

Cumulative percentage of 

variability in data set 

explained by axis.

22.84 37.33 48.77
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 19

Axis 1

-0.2

-0.5

-0.7

-0.9

-1.2

0.2

0.5

0.7

0.9

1.2

-1.2 0.2 0.5 0.7 0.9 1.2 -0.9 -0.7 -0.5 -0.2

beefcow

DA

Q

LowBaseQ

cropland

pasture

forest

forwetland

elevation

sinuosity

gradient

run

pool

WCwidth

BFwidth

BSI

opencanopy

depth

embedded

BR

cobble

gravel

sand

Figure 4. Principal components analysis biplot illustrating the relation among habitat, hydrology, and land-use (HHL) variables

for 20 sites in the Eastern Highland Rim Ecoregion.

Axis 2

12

11

8

2

15

7 18 16

10 19

17

20

6

4

9

14

5

1

1

3

13

SAMPLING SITE AND NUMBER

EXPLANATION

Note: Site numbers are identified in table 1. HHL abbreviations are identified in table 2. The location of the sites (based on site scores)

along each ordination axis specifies the location of the site relative to the axis. Variables are represented by arrows and sites are

represented by triangles. Each axis is a linear combination of multiple variables, where sites located near one another have similar

characteristics and those located far apart have dissimilar characteristics. Subgroup colors correspond to Ecoregion map shown on figure 2.

BARRENS

DISSECTED TABLELANDS

MOULTON VALLEY

SUGGESTED SUBGROUPS WITHIN THE

EASTERN HIGHLAND RIM ECOREGION

(forwetland) and occur at higher elevations (elevation) 

than other basins.

Ordination using PCA also was used to indirectly relate indirect gradient analysis differences in 

natural environmental setting to differences in cropland density. PCA site scores, which are coordinates 

along an axis specifying the location of the site relative to the axis, were correlated against cropland density. The first two ordination axes indicate that none of 

the axes, or any of the individual HHL variables, were 

significantly correlated with cropland density. Substrate embeddedness, although an important variable 

along the first axis, is not significantly correlated with 

cropland density (rho=0.10). Instead, substrate embeddedness was related to sites at low elevations having 

high percentages of pools. Clustering of sites along the 

first and second axes indicates that sites vary regionally on the basis of differences in elevation and 

streamflow. For example, sites in the Moulton Valley 

were characterized by a different group of variables 

(increase in pool, embedded, sand, and depth) than 

were sites located in the Barrens and Dissected Tablelands subregions (increase in elevation, Q, LowBaseQ, 

WCwidth, and opencanopy), indicating that HHL variability is primarily caused by differences in natural 

setting. 
20 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Figure 5. Differences in elevation and streamflow among 20 sites

in the Eastern Highland Rim Ecoregion, summarized by natural

setting or ecoregion subgroup.

Moulton Valley Dissected Tablelands Barrens

400

500

600

700

800

900

1,000

Elevation, in feet above NAVD 88

0

20

40

60

80

100

120

Streamflow, in cubic feet per second

Variation of Natural Environmental Setting 

within the Eastern Highland Rim Ecoregion

Results of the PCA of the HHL data indicate 

that differences in elevation and streamflow among 

sites in the EHR are the most important components of 

variability and may control variability in many 

instream habitats as well. This finding belies the fact 

that the EHR was delineated for the sole purpose of 

minimizing variability of natural setting. The ordination plots and distribution of elevation and streamflow 

values across the EHR were examined. The results 

suggest that the 20 EHR sites should be divided into 

three subgroups with similar natural settings, such as 

sites in the Moulton Valley, Barrens, and the Dissected 

Tablelands (fig. 5). 

Differences in elevation and streamflow among 

these three subgroups were tested using a KruskalWallis test (MathSoft, 1999). The Kruskal-Wallis test 

determines whether a difference exists among one or 

more groups, but does not identify which group is different. A difference was detected, and the Wilcoxon 

rank-sum test was performed on pairwise combinations of the subgroups to verify statistical differences 

among all three subgroups. For example, sites in the 

Moulton Valley are at lower elevations, have lower 

streamflows, have a higher percentage of pool habitat, 

and have more embedded substrates than sites located 

in either the Barrens or Dissected Tablelands subgroups. The Tennessee River was then selected as the 

northern Moulton Valley boundary. Segregation of the 

remaining sites into appropriate subgroups was not as 

straightforward. Surficial geology, along with elevation and streamflow, were the primary criteria used to 

divide the sites into either the Barrens or the Dissected 

Tablelands subgroup. The presence of the Fort Payne 

Formation and the St. Louis and Warsaw Limestones 

as dominant substrate features was used to separate 

sites in the Barrens from those in the Dissected Tablelands subgroup.

The HHL data were re-analyzed for sites 

located in the Dissected Tablelands. The Dissected 

Tablelands was selected because of the large number of sites, which added statistical power to the 

analysis. The percent of cropland in the Dissected 

Tablelands ranged from 7 to 30 percent (table 1), 

which is similar to the range of cropland percentages that was initially provided by the 20 sites in 

the EHR; however, data for sites at the low end of 

the gradient (less than 7-percent cropland) were not 

used. Elevations in the Dissected Tablelands ranged 

from 585 to 820 feet above NAVD 88, and streamflows ranged from 15 to 101 ft3/s for Q, and from 

0.55 to 13 ft3/s for LowBaseQ. 

Results from the PCA for sites in the Dissected Tablelands indicate that land use (pasture

and cropland) and other intercorrelated variables 

(beefcow, gradient, embedded, and BFwidth) were 

the most important HHL variables along the first 

axis (table 6 and fig. 6). Sites 6, 9, and 10, which 

have high percentages of cropland also were associated with a high degree of substrate embeddedness, 

an increased abundance of pool habitat, deep channels, and a high percentage of fine substrates 

(sand). Pastureland was at the opposite end of the 

land-use gradient. Increases in pastureland were 

typically associated with increased numbers of beef 

cows, wide stream channels (BFwidth), and cobblesized substrate. Along the second axis, the most 

important variables were related to natural 
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 21

Table 6. Summary statistics from the principal components analysis of the habitat, hydrology, 

and land-use variables for 11 sites in the Dissected Tablelands

[Variable abbreviations are listed in table 2; bolded variable loadings were considered important when absolute values were 0.2 or greater; HHL, habitat, hydrology, and land use]

HHL variable

Variable loadings (see fig. 6)

Axis 1

Land use

Axis 2

Streamflow

beefcow 0.30 0.07

DA 0.10 0.17

Q 0.04 0.39

LowBaseQ 0.16 0.27

cropland -0.35 0.10

pasture 0.34 -0.18

forest -0.08 0.35

forwetland -0.10 -0.32

elevation 0.17 0.22

sinuosity -0.02 0.41

gradient 0.27 0.02

run 0.25 -0.06

pool -0.30 -0.04

WCwidth 0.02 0.30

BFwidth 0.28 0.00

BSI -0.10 0.20

opencanopy 0.11 0.05

depth -0.24 0.13

embedded -0.33 -0.06

BR 0.09 0.27

cobble 0.17 -0.16

gravel -0.19 0.08

sand -0.18 -0.02

cowacre 0.28 0.04

Eigenvalues 6.56 4.41

Percentage of variability in data set explained 

by axis.

28.54 19.19

Cumulative percentage of variability in data 

set explained by axis.

28.54 47.73
22 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Axis 1

Land use

-0.3

-0.7

-1.0

-1.4

-1.7

0.3

0.7

1.0

1.4

1.7

-1.7 0.3 0.7 1.0 1.4 1.7 -1.4 -1.0 -0.7 -0.3

beefcow

DA

Q

LowBaseQ

cropland

pasture

forest

forwetland

elevation

sinuosity

gradient

run

pool

WCwidth

BFwidth

BSI

opencanopy

depth

embedded

BR

cobble

gravel

sand

Figure 6. Principal components analysis biplot illustrating the relation among habitat, hydrology, and land-use (HHL) variables

for 11 sites in the Dissected Tablelands.

6

5

10

14

9

7 12

15

11

13 8

Axis 2

Streamflow 12 SAMPLING SITE AND NUMBER

EXPLANATION

Note: Site numbers are identified in table 1. HHL abbreviations are identified in table 2. The location of the sites (based on site scores)

along each ordination axis specifies the location of the site relative to the axis. Variables are represented by arrows and sites are

represented by triangles. Each axis is a linear combination of multiple variables, where sites located near one another have similar

characteristics and those located far apart have dissimilar characteristics. The length of the arrow indicates the relative importance of the

variable to the axis. The location of the sites (based on site scores) along each ordination axis specifies the location of the site

relative to the axis. Each axis is a linear combination of multiple variables.

environmental setting and included streamflow (Q and 

LowBaseQ), percentage of basin in forest, and channel 

morphology (sinuosity and WCwidth). 

The indirect gradient analysis indicates that the 

primary gradient (axis 1) was related to cropland density (land-use gradient) (fig. 7). The most important 

factors were related to land use (pasture and cropland) 

and other intercorrelated variables (beefcow, gradient, 

embedded, and BFwidth) (table 6). However, embeddedness, which is often associated with storm runoff 

from cultivated fields, was the only variable directly 

correlated with cropland density (fig. 7). The second 

axis (streamflow gradient) was best explained by differences associated with natural setting. Variables 

included streamflow (Q and LowBaseQ), percent forest, and channel morphological characteristics (sinuosity and WCwidth).

Analyzing sites in the Dissected Tablelands separately from those in the entire EHR reduced environmental variability because of natural factors. Although 

nine sites were removed from the analysis, the likelihood of detecting relations between fish communities 

and cropland density increased. To verify that fish 

communities also differed regionally, fish-community 

data for the entire EHR were analyzed by CA, PCA, 

and IBI summaries prior to the analyses on the Dissected Tablelands subgroup (appendixes 1 and 2). 

Results of the CA indicated the same regional patterns 

as suggested by the HHL analysis. The remainder of 

the report discusses data for the 11 sites in the Dissected Tablelands only. 
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 23

Figure 7. Comparison of cropland density to site scores from the

first axis of the principal components analysis (habitat, hydrology,

and land-use variables) and substrate embeddedness for 11 sites in

the Dissected Tablelands. (Numbers represent site numbers shown

in table 1.)

6

10

5

5

9 14

7

15 11

12

8

13

6

10

5

14 7

9

15

11

12

13 8

rho = -0.86

p = 0.006

10

0

20

30

40

50

60

70

Embeddedness, in percent of substrate

-2

-1

0

1

2

Site scores from first axis of principal

components analysis

Cropland density, in percent of contributing basin cultivated

5 10 15 20 25 30

Site and number

6

rho = 0.73

p = 0.02

Site and number

Water Chemistry

Differences in water chemistry of streams in the 

Dissected Tablelands primarily were related to specific 

conductivity, which was similar to that for the 20 sites 

in the entire EHR. Specific conductance (spcond), 

which is commonly used to indicate ground-water 

resurgence, ranged from 64 to 289 microsiemens per 

centimeter (μS/cm) at 25 degrees Celsius. Nitrogen 

and phosphorus levels, which can increase as a result 

of storm runoff from adjacent croplands, ranged from 

0.79 to 3.7 milligrams per liter (mg/L) for nitrite plus 

nitrate (NO2NO3) as N and from 0.01 to 0.12 mg/L for 

orthophosphorus (Portho) as P. Other variables 

such as temperature (temp), turbidity (turbid), 

and inorganic constituents, which can also be 

influenced by landscape disturbance, displayed little variability.

Results from the PCA indicate that water 

chemistry was not a major factor in accounting 

for the variation among sites. Most of the variability was explained by differences in alkalinity (alk), specific conductance (spcond), and 

other major inorganic ions (CA, FE, and MG) 

(fig. 8 and table 7). The first PCA axis (Nutrient) was strongly related to iron (FE), specific 

conductance (spcond), nitrite plus nitrate 

(NO2NO3), and other intercorrelated variables 

(CA, alk, residue, MG, and SO4). The second 

axis (Limestone) also was influenced by variables related to specific conductance, such as 

NA, K, CL, and phosphorus (P, Pdis, and 

Portho) levels; however, phosphorus levels at 

site 11 heavily influenced the interpretation. 

For example, the orthophosphorus (Portho) 

level at site 11 was 0.13 mg/L, whereas the 

median level for the other sites was only 

0.02 mg/L. The elevated phosphorus levels 

were unexplained, yet were not considered to 

be related to cropland because of the low percentages of cropland in the basin.

The indirect gradient analysis revealed 

that the first PCA axis was significantly correlated with cropland density (fig. 9). Important 

variables, as aforementioned, were related to 

specific conductivity (spcond) and nutrients 

(NO2NO3) (Nutrient gradient). Nitrate 

(NO2NO3) was the only variable positively 

correlated with cropland density (fig. 9). The 

positive correlation between specific conductivity (spcond) and nitrate (NO2NO3) indicates 

that the more influence ground water has on streamflow, the more nitrate is likely to be present in the 

stream; thus, ground water could be transporting, 

rather than diluting, nitrate. The indirect gradient 

analysis of the second axis (Limestone gradient) did 

not show a clear correlation. The dominant variables 

(NH4, NH4dis, NH4total, P, Pdis, and Portho) indicate 

a strong nutrient influence; however, site scores from 

the second axis did not correlate with cropland density. 

The unexplained differences are presumed to be 

related to underlying natural gradients, such as elevation and geology, or to variables that were unaccounted for in the analysis.
24 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Figure 8. Principal components analysis biplot illustrating the relation among water-chemistry variables for 11 sites

in the Dissected Tablelands.

Axis 1

Nutrient

-0.4

-0.9

-1.3

-1.8

-2.2

0.4

0.9

1.3

1.8

2.2

-2.2 0.4 0.9 1.3 1.8 2.2 -1.8 -1.3 -0.9 -0.4

temp

pH

spcond

alk

NH4

NH4dis

NO2NO3 NH4total

Pdis

P

Portho

turbid

EC

CA

SIO2

residue

FE

K

NA

CL

MG

MN

SO4

DOC

Axis 2

Limestone

10

9

6

15

14

8 7

12 13

11

5

12 SAMPLING SITE AND NUMBER

EXPLANATION

Note: Site numbers are identified in table 1. Water-chemistry abbreviations are identified in table 3. Water-chemistry variables are represented

by arrows and sites are represented by triangles. Sites and variables located near one another have similar characteristics and those located far

apart have dissimilar characteristics. The length of the arrow indicates the relative importance of the variable to the axis. The location of the

sites (based on site scores) along each ordination axis specifies the location of the site relative to the axis. Each axis is a linear combination

of multiple variables.

The small amount of variability explained by 

the ordination of the water chemistry data indicates 

that streams within the Dissected Tablelands are not 

greatly influenced by increases in cropland directly or 

are not accurately characterized based on the single 

base-flow sample. Detected differences between sites 

were related to specific conductance, which is 

expected because ground water is the primary source 

of streamflow during base-flow periods. The increased 

nitrite plus nitrate levels with increased cropland density indicates that nitrogen levels are influenced, to 

some degree, by cropland density. 

Fish Communities

The fish-community data set for the Dissected 

Tablelands consists of a total of 7,586 individual fish 

(compared to 10,550 in the full EHR data set), representing 53 species (compared to 65 in the full EHR 

data set) in 11 families (compared to 15 in the full 

EHR data set) (table 8 and appendix 3). The cyprinids 

(minnows), percids (darters), and centrarchids (sunfish) were the most common groups of fishes. Nine 

species (largescale stoneroller, scarletfin shiner, striped 

shiner, longear sunfish, bluegill, banded sculpin, green 

sunfish, redline darter, and black darter) accounted for 

over 75 percent of individuals collected at Dissected 

Tablelands sites. One Federally threatened species, 

slackwater darter (Etheostoma boschungi), and one 

species of special concern, flame chub (Hemitremia 

flammea), also were collected and released during the 

survey. The largescale stoneroller (Campostoma oligolepis) was the most common species, making up 

25 percent of the total abundance. Species from the 

full EHR data set not represented at sites in the 
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 25

Slackwater Darter (Etheostoma boschungi), Federal

Rank—Listed as Endangered. The slackwater darter is

a Highland Rim endemic that is restricted to Highland

Rim streams in and along the southern bend of the

Tennessee River (Flint River, Shoal Creek, Limestone

Creek, and Buffalo River). Usually found in the slower

moving waters of pools, it is often associated with leaf

litter and detritus and spawns in seasonally flooded or

seepage areas of open fields (Boschung, 1976).

(Photograph by J.R. Shute, Conservation Fisheries, Inc.

Used with permission.)

Dissected Tablelands were the freshwater drum (Aplodinotus grunniens), streamline chub (Erimystax dissimilis), northern studfish (Fundulus catenatus), brook 

silverside (Labidesthes sicculus), longnose gar (Lepisosteus osseus), ribbon shiner (Lythrurus fumeus), 

mountain shiner (Lythrurus lirus), bigeye shiner (Notropis boops), sauger (Stizostedion canadense), rainbow trout (Oncorhynchus mykiss), blackstripe 

topminnow (Fundulus notatus), and creek chubsucker 

(Erimyzon oblongus). Only one non-native species 

(redbreast sunfish, Lepomis auritus) was collected, 

representing only 1 percent of the individual fish collected at the 11 sites in the Dissected Tablelands.

Ordination (CA) of the fish-community data 

resulted in two interpretable axes. Species along the 

first axis generally followed a lentic to lotic habitat 

(LowFlow gradient). Fishes at the lotic end of the gradient included the percids (ETHBLE, ETHRUF, and 

ETHFLA), cyprinids (CYPGAL, NOTTEL, 

NOTVOL, NOTRUB, CLIFUN, and NOTAMB), and 

centrarchids (AMBRUP and MICDOL) (fig. 10 and 

table 9). Fishes at the lentic end of the gradient 

included centrarchids (LEPGUL, LEPMIC, LEPMAC, and MICSAL), cyprinids (HEMFLA and RHIATR), and one each poecilid (GAMAFF), 

cyprinodontid (FUNOLI), and ictalurid (ICTPUN). 

Interpretation of the second axis (Percinids gradient) 

was not as clear but trended toward a gradient mixed 

with cyprinids (HEMFLA, RHIATR, CLIFUN) and 

centrarchids (MICDOL, LEPMIC, and LEPMAC) to 

percids (ETHBLE, ETHRUF, ETHSIM, and 

ETHKEN).

Table 7. Summary statistics from the principal components 

analysis of the water-chemistry variables for 11 sites in the 

Dissected Tablelands 

[Variable abbreviations are listed in table 3; bolded variable loadings 

were considered important when absolute values were 0.2 or greater]

Water-chemistry 

variable

Variable loadings (see fig. 8)

Axis 1

Nutrient

Axis 2

Limestone

temp 0.11 -0.22

pH -0.20 0.06

spcond -0.26 0.16

alk -0.27 0.15

NH4 0.16 0.30

NH4dis 0.18 0.29

NH4total 0.20 0.25

NO2NO3 -0.21 0.22

P 0.18 0.29

Pdis 0.18 0.28

Portho 0.16 0.30

DOC 0.26 0.12

turbid -0.21 0.06

EC -0.20 0.08

CA -0.26 0.15

SIO2 -0.18 0.17

FE 0.25 0.09

K 0.20 0.24

NA -0.03 0.29

CL -0.17 0.23

MG -0.27 0.14

MN 0.09 -0.13

SO4 -0.24 0.00

Eigenvalues 10.82 7.45

Percentage of variability in data set 

explained by 

axis.

45.07 31.03

Cumulative percentage of variability in data set 

explained by 

axis.

45.07 76.10
26 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Figure 9. Comparison of cropland density to site scores from the

first axis of the principal components analysis (water-chemistry

variables) and to nitrate concentrations for 11 sites in the Dissected

Tablelands. (Numbers represent site numbers shown in table 1.)

13

11

12

8

7

15

9

14

5

10

6

5

13

12

8 15

11

7 9

14

10

6

-2

-3

-1

0

1

2

0.5

1.5

2.5

3.5

4.0

Nitrite plus nitrate concentration,

in milligrams per liter

Site scores from waterchemistry variables

5 10 15 20 25 30

Cropland density, in percent

6

rho = -0.80

p = 0.01

rho = 0.69

p = 0.03

Site and number

5 Site and number

The most responsive community metrics were 

percentages of omnivores and stonerollers (omnivores), tolerant species (tolerant), specialized insectivores (spinsect), and simple lithophilic spawners 

(simLiths) (table 10). Ordination (PCA) of the 14 community metrics indicates that sites generally were 

influenced most by the number of species and the different feeding classes (fig. 11 and table 11). The first 

axis clearly displays a species diversity gradient, 

where the most important metrics were the number of 

native species (natives), number of darter species 

(darters), catch rate (catchrate), and percentages of 

fish as specialized insectivores (spinsect) and simple 

lithophilic spawners (simLiths). The intercorrelation 

among several of these metrics should be noted. For 

example, the majority of the percids also are classified as specialized insectivores and simple 

lithophilic spawners. The second axis appears to 

generally describe sites based along a habitat gradient. Sites 9, 10, and 6 at the “degraded” end of 

the gradient were associated with high percentages of tolerant species (tolerant), physical 

abnormalities (anomalies), and hybrids (hybrid), 

whereas sites 15, 13, 11, and 8 at the opposite end 

of the gradient were represented by high percentages of specialized insectivores (spinsect) and 

simple lithophilic spawners (simLiths). The most 

important metrics along the second axis were the 

number of darter species (darters) and percentages of individuals with abnormalities (anomalies 

and DELT), as tolerant species (tolerant) and as 

specialized insectivores (spinsect). 

IBI scores ranged from 32 to 48 and had a 

mean score of 41 (table 11). The IBI was not 

designed to detect changes in fish communities 

caused by a single source or stressor. The IBI can 

at times detect these differences; however, the 

sensitivity of the analysis lies in the initial objective for which the scoring criteria were established—to provide a numerical value 

representing the integrity of the contributing 

basin and not to address causative factors. In 

most cases, the IBI is used as a means of ranking 

and priortizing watersheds based on a streamhealth rating. The scores provided in this report 

simply serve as comparison to the CA and PCA 

and as a conservative approach to fishcommunity assessment.

Response of Fish Communities to Cropland 

Density and Natural Environmental Setting

Fish communities were summarized by CA, 

PCA, and IBI and were correlated with natural and 

anthropogenic factors to determine response of the 

fish communities to environmental differences associated with natural setting and cropland density. Because 

each summarization procedure possesses unique 

advantages and disadvantages, the manner in which 

the fish-community data set was summarized during 

each procedure is quite different. For example, the CA 

was summarized on the basis of individual taxa relative abundance, whereas the PCA was summarized on 

the basis of individual community metrics, which 

groups taxa having similar ecologic or taxonomic 
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 27

Table 8. Fish species collected at 11 sites in the Dissected Tablelands—Continued

Common name Scientific name Species 

abbreviation

Number 

of sites 

with collections

Number of 

individuals 

collected

Relative 

abundance 

(percent)

Largescale stoneroller Campostoma oligolepis CAMOLI 11 1,926 25

Scarletfin shiner Lythrurus fasciolaris LYTARD 10 980 13

Striped shiner Luxilus chrysocephalus LUXCHR 11 625 8

Longear sunfish Lepomis megalotis LEPMEG 10 571 8

Bluegill Lepomis macrochirus LEPMAC 11 458 6

Banded sculpin Cottus carolinae COTCAR 10 394 5

Green sunfish Lepomis cyanellus LEPCYA 11 377 5

Redline darter Etheostoma rufilineatum ETHRUF 3 251 3

Black darter Etheostoma duryi ETHDUR 11 226 3

Northern hog sucker Hypentelium nigricans HYPNIG 11 180 2

Snubnose darter Etheostoma simoterum ETHSIM 6 161 2

Bigeye chub Notropis amblops NOTAMB 5 151 2

Rainbow darter Etheostoma caeruleum ETHCAE 8 138 2

Bluntnose minnow Pimephales notatus PIMNOT 9 115 2

Rock bass Ambloplites rupestris AMBRUP 6 94 1

Redbreast sunfish (C) * Lepomis auritus LEPAUR 3 90 1

Telescope shiner Notropis telescopus NOTTEL 1 90 1

Whitetail shiner Cyprinella galactura CYPGAL 4 80 1

Warmouth Lepomis gulosus LEPGUL 9 66 <1

Fantail darter Etheostoma flabellare ETHFLA 2 61 <1

Mimic shiner Notropis volucellus NOTVOL 2 60 <1

Slender madtom Noturus exilis NOTEXI 3 57 <1

Blackspotted topminnow Fundulus olivaceus FUNOLI 7 44 <1

Largemouth bass Micropterus salmoides MICSAL 10 42 <1

Western mosquitofish Gambusia affinis GAMAFF 5 40 <1

Greenside darter Etheostoma blennioides ETHBLE 3 38 <1

Golden redhorse Moxostoma erythrurum MOXERY 5 31 <1

Black redhorse Moxostoma duquesnei MOXDUQ 3 30 <1

Logperch Percina caprodes PERCAP 5 29 <1

Blackfin darter Etheostoma nigripinne ETHNIG 5 24 <1

Hybrid sunfish Lepomis spp. LEP_SP 5 18 <1

Yellow bullhead Ameiurus natalis AMENAT 7 13 <1

Redear sunfish Lepomis microlophus LEPMIC 5 13 <1

Black bullhead Ameiurus melas AMEMEL 1 13 <1

Flame chub *** Hemitremia flammea HEMFLA 2 11 <1

Spotted bass Micropterus punctulatus MICPUN 3 10 <1

Chain pickerel Esox niger ESONIG 3 10 <1

Blacknose dace Rhinichthys atratulus RHIATR 4 10 <1

Stripetail darter Etheostoma kennicotti ETHKEN 3 9 <1

Spotfin shiner Cyprinella spiloptera CYPSPI 9 9 <1

Least brook lamprey Lampetra aepyptera LAMAEP 4 7 <1

White sucker Catostomus commersoni CATCOM 3 6 <1

Unidentified lamprey (C) Ichthyomyzon sp. ICHsp 1 5 <1

Table 8. Fish species collected at 11 sites in the Dissected Tablelands

[*, non-native; **, Federally listed as “threatened”; ***, State listed as special concern; <, less than; (C), censored; species are listed in order of 

number of individuals collected; a complete list of all fishes collected at the 20 sites in the Eastern Highland Rim is given in appendix 3]
28 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Figure 10. Correspondence analysis biplot illustrating the relation among fish abundances for 11 sites in the

Dissected Tablelands.

Axis 1

Low flow

AMBRUP

AMEMEL

AMENAT

CAMOLI

CATCOM

CHOAGS

CLIFUN

COTCAR

CYPGAL

CYPSPI

ESONIG

ETHBLE

ETHBOS

ETHCAE

ETHDUR

ETHFLA

ETHKEN

ETHNIG

ETHRUF

ETHSIM

FUNOLI

GAMAFF

HEMFLA

HYPNIG

ICTPUN

LAMAEP

LEPGUL LEPMAC LEPCYA

LEPMEG

LEPMIC

LUXCHR

LYTARD

MICDOL

MICPUN

MICSAL MINMEL

MOXDUQ

MOXERY

NOTAMB

NOTEXI

NOTRUB

NOTTEL

NOTVOL

PERCAP

PERSCI

PIMNOT

POMNIG

RHIATR

SEMATR

-0.3

-0.7

-1.0

-1.4

-1.7

0.3

0.7

1.0

1.4

1.7

-1.7 -1.4 -1.0 -0.7 -0.3 0.3 0.7 1.0 1.4 1.7

Axis 2

Percinids

6

10

14 11

13

7 12

9

15 8

5

15 SAMPLING SITE AND NUMBER

EXPLANATION

Actual cropland density, in percent of contributing basin cultivated

0 15 25 35

8 7,15 5 10 6

9

11

12 13 14

Sampling sites and numbers

Rosyface shiner Notropis rubellus NOTRUB 1 5 <1

Black crappie Pomoxis nigromaculatus POMNIG 1 4 <1

Spotted sucker Minytrema melanops MINMEL 3 3 <1

Dusky darter Percina sciera PERSCI 5 3 <1

Rosyside dace Clinostomus funduloides CLIFUN 2 2 <1

Creek chub Semotilus atromaculatus SEMATR 1 2 <1

Smallmouth bass Micropterus dolomieu MICDOL 1 1 <1

Channel catfish Ictalurus punctatus ICTPUN 1 1 <1

Spring cavefish Forbesichthys agassizi CHOAGS 1 1 <1

Slackwater darter ** Etheostoma boschungi ETHBOS 1 1 <1

Creek chubsucker Erimyzon oblongus ERIOBL 1 1 <1

Total abundance 7,586

Table 8. Fish species collected at 11 sites in the Dissected Tablelands—Continued

Common name Scientific name Species 

abbreviation

Number 

of sites 

with collections

Number of 

individuals 

collected

Relative 

abundance 

(percent)
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 29

Table 9. Summary statistics from the correspondence 

analysis of the fish-abundance data for 11 sites in the 

Dissected Tablelands

[Species abbreviations are listed in table 8; variable loadings listed for 

selected species]

Species abbreviation

Variable loadings (see fig. 10)

Axis 1

Low flow

Axis 2

Percinids

AMBRUP 0.78 -0.36

CAMOLI 0.34 -0.01

CATCOM -0.09 1.35

CLIFUN 0.89 0.93

CYPGAL 0.80 0.28

CYPSPI 0.62 -0.31

ESONIG -0.64 -0.90

ETHBLE 1.31 -0.06

ETHCAE 0.32 -0.26

ETHFLA 1.19 0.40

ETHKEN -0.38 -0.85

ETHNIG -0.39 0.56

ETHRUF 1.24 -0.31

ETHSIM 0.51 -0.44

FUNOLI -0.59 -0.83

GAMAFF -1.11 0.12

HEMFLA -0.74 1.11

LEPGUL -0.63 0.25

LEPMAC -0.37 0.19

LEPMEG -0.45 -0.22

LEPMIC -0.49 0.36

LYTARD -0.18 -0.52

MICPUN 0.52 -0.48

MICSAL -0.27 0.02

MINMEL -0.39 -0.03

MOXDUQ 0.47 1.02

MOXERY 0.07 0.85

NOTAMB 0.73 -0.38

NOTEXI -0.58 -0.96

NOTTEL 0.80 0.44

NOTVOL 0.76 0.40

PERCAP -0.48 -0.11

PERSCI -0.63 0.51

RHIATR -0.42 1.11

SEMATR 0.09 0.50

Eigenvalues 0.22 0.15

Percentage of variability 

in data set explained 

by axis

26.24 17.77

Cumulative percentage 

of variability in data 

set explained by axis

26.24 44.00

Table 10. Summary statistics from the principal 

components analysis of the community metrics for 

11 sites in the Dissected Tablelands

[Metric abbreviations are listed in table 4; bolded variable loadings were considered important when absolute values were 

greater than 0.30]

Species

Variable loadings (see fig. 11)

Axis 1 Axis 2

Species 

diversity Habitat

natives 0.43 -0.12

omnivores 0.25 0.12

darters 0.32 -0.33

anomalies 0.28 0.34

sunfish -0.18 -0.25

suckers 0.08 0.29

intols 0.32 0.05

tolerant 0.23 0.40

spinsect 0.17 -0.40

pisc 0.09 -0.28

catchrate 0.37 -0.13

hybrid -0.13 0.24

simLiths 0.28 -0.23

DELT 0.34 0.27

Eigenvalues 4.31 3.71

Percentage of variability in data set 

explained by axis.

30.80 26.48

Cumulative percentage of variability in 

data set explained 

by axis.

30.80 57.29
30 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

Alabama and Tennessee, 1999

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, Table 11. Summary of fish-community metrics and Index of Biological Integrity scores for 11 sites in the Dissected Tablelands [Full site names are listed in table 1; metrics reported here are presumed indicators of anthropogenic disturbance; see appendix 4 for species tolerances, feeding guilds

abbreviations are shown in table 4; *, denotes metrics used in Index of Biological Integrity calculation] Site abbrevia- tion Site number Community metric natives* omni- vores* darters* anomalies* sunfish* suckers* intols* tolerant* spinsect* pisc* catch- rate* 

Beans 5 28 35.6 6 2.3 3 4 5 16.2 40.4 1.1 49 Bdam 6 19 4.1 3 0.5 5 2 0 13.2 9.1 0.5 14 BrierF 7 23 37.1 4 1.1 6 3 1 6.1 20.0 2.5 49 FlintLin 8 26 54.8 8 0.6 5 2 1 9.7 32.5 2.3 95 Hester 9 25 46.9 4 23.1 4 3 2 36.4 14.3 1.3 61 Indian 10 19 31.1 2 0.5 5 5 1 14.8 4.3 1.0 28 Lime 11 22 18.2 4 0.5 6 1 0 11.4 50.8 1.9 27 LitLim 12 19 59.6 3 0.4 4 1 2 12.7 17.5 3.2 43 Piney 13 23 11.6 6 1.8 5 2 1 11.9 52.6 0.5 51 RndIs 14 20 4.0 3 0.9 4 1 1 9.9 29.2 0.9 27 Wfork 15 25 20.6 7 0.6 6 1 2 5.3 40.2 6.7 57 
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 31

Axis 1

Species

diversity

-0.3

-0.6

-0.9

-1.2

-1.5

0.3

0.6

0.9

1.2

1.5

-1.5 0.3 0.6 0.9 1.2 1.5 -1.2 -0.9 -0.6 -0.3

natives

omnivores

darters

anomalies

sunfish

suckers

intols

tolerant

spinsect

pisc

catchrate

hybrid DELT

simLiths

Figure 11. Principal components analysis biplot illustrating the relation among fish-community metrics for 11 sites in the

Dissected Tablelands.

Axis 2

Habitat

6

10

14

7 12

11 13

15

8

5

9

Actual cropland density, in percent of contributing basin cultivated

0 15 25 35

8 7,15 5 10 6

9

11

12 13 14

Sampling sites and numbers

15 SAMPLING SITE AND NUMBER

EXPLANATION

Note: Site numbers are listed in table 1. Metric abbreviations listed in table 4.

characteristics. The IBI, which is probably the most 

conservative of these three procedures, summarizes 

fish-community data and calculates a numeric score 

based on 12 community metrics. Recognizing these 

fundamental differences, all three procedures detected 

differences related to HHL quality; however, only the 

CA indicated that these differences were significantly 

correlated with cropland density. None of the procedures indicated a statistically significant response to 

water chemistry.

Ordination of the HHL variables identified land 

use as the dominant gradient at sites in the Dissected 

Tablelands; however, the indirect gradient analysis of 

CA site scores along with HHL variables indicates that 

fish communities were affected slightly more by 

streamflow and elevation than by land use (table 12). 

The indirect gradient analysis of site scores from CA 

axis 1, which was described as the flow gradient, with 

streamflow and elevation suggests some darter 

(ETHRUF, ETHBLE, and ETHFLA) and minnow 

(CAMOLI, NOTVOL, and CYPGAL) species prefer 

sites at higher elevations and sustained streamflows 

(table 12 and fig. 10). As streamflow and elevation 

decrease, sunfish (LEPGUL, LEPMAC, LEPMEG, 

MICSAL, and LEPMIC), topminnows (FUNOLI), and 

livebearers (GAMAFF) were more common. Darters 
32 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

(ETHKEN, ETHNIG, PERSCI, and PERCAP) and 

minnows (LYTARD and PIMNOT) were found at 

low-elevation streamflow sites but were represented 

by a somewhat different group of species that possibly 

are more tolerant of low sustained streamflows. 

Streams with unstable streamflows support fish communities that are more likely to recover quickly from 

disturbance than do streams with more predictable 

flows (Poff and Ward, 1990). Dispersion of site scores 

along CA axis 2 were not as great as along the CA 

axis 1, which means less variability existed between 

sites (fig. 10). The positive correlation between axis 2 

and cropland density, and the negative correlation with 

pasture suggests that several sucker and minnow species preferred, or were more tolerant of, increases in 

cropland and substrate embeddedness. Although the 

abundance of some species increased as percentages of 

pasture and numbers of beef cows increased, fishes 

actually may be responding positively to a lack of disturbance. For example, although numbers of beef 

cows generally increased with the amount of pastureland, the maximum number of cows per acre was low 

at about four cows per acre. This suggests that pastures 

are not being overgrazed, and more importantly, pastures are either lying dormant or primarily are being 

used for hay production, which does not seem to pose 

a severe negative impact on fishes.

The indirect gradient analysis of the PCA site 

scores based on the community metrics suggests that 

community metrics were slightly less responsive to 

environmental characteristics related to natural setting 

or cropland density when compared to CA site scores. 

Site scores from the first PCA axis were negatively 

correlated with substrate embeddedness and positively 

correlated with elevation and numbers of beef cows, 

indicating that some community metrics responded 

negatively to cropland density (table 12). Sites 5, 8, 

and 9 at the upper end of the Low flow gradient contained high numbers of individuals and had the highest 

species diversity of the sites in the Dissected Tablelands, yet also had high percentages of abnormalities. 

Sites 6, 10, and 14 at the low end of the gradient contained high numbers of sunfish species and slightly 

Table 12. Summary of indirect gradient analysis relating site scores from the correspondence analysis and principal 

components analysis of the fish-community data to selected habitat, hydrology, and land-use variables for 11 sites in the 

Dissected Tablelands

[Bolded p-values significant at p<0.05. See table 2 for description of environmental variable descriptions and table 4 for description of fish-community metrics; CA, correspondence analysis of fish-community data; PCA, principal components analysis of community metric data; IBI, Index of Biological Integrity] 

Environmental

variable

abbreviation

Correlation coefficient (ρ) and statistical significance

Site scores from CA

(relative abundance) (see fig. 10)

Site scores from PCA

(individual metrics) (see fig. 11) IBI

(Integrated metrics) Axis 1

Low flow

Axis 2

Percinids

Axis 1

Species diversity

Axis 2

Habitat

ρ pvalue ρ p-value ρ p-value ρ p-value ρ p-value

elevation 0.72 0.024 -0.01 0.954 0.67 0.037 0.29 0.372 0.27 0.393

DA 0.29 0.365 -0.10 0.741 0.33 0.308 0.21 0.518 0.57 0.070

pasture 0.23 0.464 -0.71 0.039 0.46 0.147 -0.15 0.615 0.36 0.361

BFwidth 0.20 0.537 -0.69 0.027 0.54 0.093 -0.10 0.741 0.39 0.225

embedded -0.41 0.190 0.71 0.025 -0.85 0.007 0.17 0.592 -0.68 0.030

LowBaseQ 0.78 0.010 0.26 0.413 0.50 0.117 0.29 0.365 0.22 0.497

gradient 0.41 0.195 -0.42 0.176 0.54 0.089 0.06 0.863 0.32 0.314

cobble 0.49 0.122 0.12 0.707 0.16 0.633 0.16 0.623 0.04 0.899

beefcow 0.66 0.037 -0.47 0.131 0.78 0.014 0.23 0.481 0.59 0.060

cropland -0.20 0.518 0.72 0.024 -0.50 0.111 0.14 0.677 -0.40 0.204
Environmental Characteristics and Fish Communities in the Eastern Highland Rim Ecoregion 33

more hybrids. The Habitat axis was not significantly 

correlated with any of the community metrics (fig. 11).

The IBI, as expected, provided similar results as 

the PCA of the individual metrics. However, because 

metrics were integrated into a single score, the scores 

were less sensitive to change in natural setting and 

cropland density. For example, the only HHL variable 

directly correlated with IBI scores was substrate 

embeddedness, which suggests that the effects from 

natural setting or cropland density may be obscured by 

the integration of metrics.

Although the intent of this report is not to 

develop specific criteria, such as community metrics 

or individual taxa, for modeling changes in cropland 

density or natural environmental setting, generally 

summarizing how individual community metrics 

directly responded to cropland density and the environmental gradients deemed most important by the 

indirect gradient analysis is beneficial. By performing 

an indirect gradient analysis that correlates site scores 

from the PCA of the environmental data to community 

metrics, the variability due to complex instream processes may be minimized and transferred to a more 

interpretable set of environmental variables and fishcommunity characteristics. The results could therefore 

be used as an ecologically based management tool that 

demonstrates how certain community metrics (in 

stream basins about 30 to 100 square miles located in 

the Dissected Tablelands) generally will respond to 

changes in cropland allotments and streamflowaltering perturbations.

The indirect gradient analysis of 13 community 

metrics revealed that the percentage of specialized 

insectivores was the only metric that was significantly 

correlated with the land-use gradient (table 13). Other 

metrics responded similarly, but correlations were not 

statistically significant at p<0.05 (fig. 12). This indicates that increases in cropland density directly affect 

fishes that require clean substrates to successfully feed 

and reproduce. Substrate embeddedness not only 

Table 13. Summary of indirect gradient analysis relating site physical and water-chemistry data scores from the principal 

components analysis and cropland density to fish-community metrics for 11 sites in the Dissected Tablelands

[Bolded p-values significant at p<0.05. See table 4 for description of fish-community metrics; PCA, principal components analysis of community metric 

data; HHL, habitat, hydrology, and land use] 

Community

metric

abbreviation

Correlation coefficient (ρ) and statistical significance

Site Scores from PCA

(HHL data)

(see fig. 6)

Site scores from PCA

(water-chemistry data)

(see fig. 8) Cropland density

Axis 1

Land use

Axis 2

Streamflow

Axis 1

Nutrient

Axis 2

Limestone

ρ pvalue ρ p-value ρ p-value ρ p-value ρ p-value

natives 0.41 0.195 0.54 0.088 -0.15 0.610 -0.16 0.610 -0.18 0.560

anomalies -0.03 0.908 0.51 0.107 -0.23 0.476 -0.17 0.581 0.02 0.954

sunfish 0.01 0.976 -0.39 0.208 0.53 0.100 -0.21 0.500 -0.22 0.472

DELT 0.01 0.988 0.34 0.294 -0.29 0.344 -0.17 0.590 0.12 0.715

tolerant 0.15 0.635 -0.39 0.211 0.37 0.244 -0.54 0.087 -0.40 0.201

darters 0.62 0.051 0.42 0.191 0.17 0.597 -0.27 0.379 -0.45 0.146

simLiths 0.51 0.111 0.46 0.147 0.29 0.365 0.01 0.998 -0.50 0.111

spinsect 0.64 0.046 0.27 0.396 0.49 0.124 -0.06 0.829 -0.55 0.077

omnivores 0.50 0.117 -0.01 0.966 -0.06 0.829 -0.01 0.966 -0.35 0.256

catchrate 0.51 0.112 0.34 0.285 -0.04 0.885 -0.41 0.189 -0.45 0.153

pisc 0.46 0.154 -0.45 0.154 0.21 0.517 -0.35 0.267 -0.40 0.200

intols 0.24 0.463 0.18 0.582 -0.47 0.135 -0.19 0.532 -0.04 0.879

suckers -0.32 0.300 0.41 0.20 -0.57 0.070 0.33 0.304 0.43 0.175

hybrid -0.27 0.388 -0.25 0.424 0.21 0.518 0.22 0.488 0.06 0.849
34 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

0

10

20

30

40

50

60

Fish as specialized omnivores, in percent

2

1

3

4

5

6

7

8

9

Number of darter species present

-2.0 -1.5 -1.0 -0.5 0 0.5 1.0 1.5

Site scores from the first axis of principal components analysis

20

0

40

60

80

100

Catch rate, in number of fish

collected per 300 feet

Land-use gradient

Increasing:

cropland (cultivated)

substrate embeddedness

(embedded)

Increasing:

pastureland (pasture)

numbers of beef cows

(beefcow)

EXPLANATION

SMOOTHING SPLINE

SAMPLE SITE

Figure 12. Response of selected fish-community metrics to

site scores from axis 1 of the principal components analysis.

affects species that feed by browsing, grazing, filtering, and stalking but also may directly affect aquatic 

invertebrates and periphyton, which the fish eat. Berkman and Rabeni (1987) also showed that sediment was 

detrimental to insectivores, herbivores, and lithophils 

in Missouri streams. The streamflow gradient, which 

was primarily interpreted as differences in elevation 

and steamflow, also could have negative implications 

on several community metrics (natives, anomalies, 

and simLiths). Although correlations were not statistically significant at p<0.05, the positive correlation 

between streamflow and numbers of native species, 

percentages of abnormalities and simple lithophilic 

spawners could be used to better manage streamflow 

during low hydrologic periods. For example, decisions 

concerning the permitting of instream habitat-altering 

practices and water withdrawals might be based on a 

7-day 10-year low flow (7Q10), which highlights the 

potential vulnerability of some Federally listed fishes. 

Because a large number of Federally listed species in 

the LTEN are classified as simple lithophilic spawners, 

the affects of removing water from a stream that 

already has a low base flow during drier periods ultimately could jeopardize the existence of some sensitive species. The lack of response of the omnivore and 

stoneroller metric, which is sometimes anecdotally 

used to indicate changes in nutrient levels from agricultural sources, was unexpected. In other studies, 

increases in stoneroller percentages have been associated with increases in nutrient levels from agricultural 

activities and general habitat degradation (Power and 

Mathews, 1983; Maret, 1997; Petersen, 1998). 

Species like the fantail darter (Etheostoma flabellare), stripetail

darter (E. kennicotti), and blackfin darter (E. nigripinne) are

members of the group of fishes known as Catonotus. These

fishes are highly sensitive to sedimentation because they

physically attach their eggs to the undersides of rocks. As

sediment fills crevices and voids in the substrate, suitable

nesting sites are difficult to locate. (Photograph by B.M. Burr

and L.M. Page, Southern Illinois University and University

of Florida, respectively. Used with permission.)
Conclusions 35

Although the stoneroller was the most abundant fish in 

the Dissected Tablelands, abundances did not respond 

to changes in nutrients or cropland density. Stonerollers generally were more sensitive to changes in reach 

gradient, substrate size, and streamflow; they prefer 

high gradients, cobble-size substrate, and a high baseflow.

CONCLUSIONS

The purpose of this study was to identify the primary environmental characteristics that influence fishcommunity structure in the Eastern Highland Rim of 

the lower Tennessee River Basin. Minimizing natural 

variability enhances our ability to detect differences 

caused by agricultural factors. However, fish communities within the Eastern Highland Rim are influenced 

more by natural factors, such as streamflow and 

elevation, than by factors associated with percentages 

of cropland. Although ecoregions are defined as geographic areas with homogeneous biological communities and terrestrial characteristics (soils, vegetation, 

climate, geology, physiography), ecoregion boundaries should not always be “flatly” accepted because 

of the heterogeneous nature of rivers and physiographic regions. Based on the indirect gradient analysis, sites were subdivided into the Moulton Valley, the 

Dissected Tablelands, and the Barrens to further minimize natural variability.

Elevation and streamflow, followed by land use, 

were the most important gradients that influenced fishcommunity structure at the 11 sites of the Dissected 

Tablelands subgroup and in the 20 sites in the Eastern 

Highland Rim. Substrate embeddedness was correlated negatively with the second correspondence 

analysis axis and several community metrics, indicating that most fishes in the Dissected Tablelands 

require clean substrates to successfully feed and reproduce. Embeddedness not only inhibits feeding behavior but also directly affects food availability. Even 

though sedimentation is one of the most common pollutants to aquatic systems, differentiating anthropogenic sources from natural sources is difficult.

Although a large amount of literature exists 

relating agriculture and the damaging effects of sediment on stream fishes in western streams, such studies 

have been limited in the Southeast, which supports the 

most diverse and also the most imperiled aquatic fauna 

in North America. Research has primarily focused on 

a select number of species and failed to address the 

effects of sediment on entire fish communities. The 

analysis presented here documents that fish communities in the Dissected Tablelands respond negatively to 

increases in substrate embeddedness and further documents that embeddedness correlates positively to cropland density. However, to suggest that fish-community 

degradation is related directly to cropland density, in 

all cases, would be premature. For example, the reason 

intensively cultivated areas are located along river bottoms and not along the ridges is because of the deep, 

fertile soils associated with alluvial deposits along 

river terraces. In this case, embeddedness could be the 

result of natural processes, where erosion is accelerated by cultivation. Alternatively, the embeddedness 

gradient among sites in the Dissected Tablelands may 

be in response to historical or transitional land use 

rather than to the present cropland-density gradient. 

The watersheds of Beaverdam Creek and Indian Creek 

in the Eastern Highland Rim that were among the most 

embedded of all sites in the Dissected Tablelands have 

been intensively cultivated, but within the last 5 to 

10 years, these two sites have undergone a transition 

from crop to residential land use. The observed 

embeddedness could be the result of historical land 

uses or more recent land disturbances, such as residential construction. Alternatively, Hester Creek and 

Beans Creek, which also are heavily embedded, drain 

predominately agricultural areas that have not undergone any land-use changes over the last 20 years. 

Whatever the source of sediment, fish communities 

are impaired as sedimentation and embeddedness 

increase.

Although a distinct response threshold was not 

identified in this study, fish communities were affected 

negatively by increases of cropland density in the Dissected Tablelands. Other studies have documented a 

threshold response when basins approach 50-percent 

cultivation. Future methods for monitoring changes at 

the ecoregion scale should consider variation in natural setting as well as the variety of stressors associated 

with agriculture. For example, methods applicable in 

the corn-belt region of the Midwest probably will not 

be effective for detecting changes in fish communities 

downstream from confined animal feeding operations 

or downstream from small patches of land cultivated 

for cotton and soybeans in the Southeast. The challenge now is in selecting a relevant suite of fish indicators that will respond to a full range of land-use 

changes. Community-level indicators, therefore, 

should be tailored to address individual problems and 
36 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

should not function as a remedy for all types of landscape disturbances. The techniques presented in this 

report should prove useful in narrowing the suitable 

list of candidate fish-community metrics and in establishing predictive criteria for streams in the Eastern 

Highland Rim.

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APPENDIXES

Appendix 1 41

Appendix 1. Summary of indirect gradient analysis relating site scores from the correspondence analysis and principal 

components analysis of the fish-community data to selected habitat, hydrology, and land-use variables for 20 sites in the 

Eastern Highland Rim Ecoregion

[p-values significant at p<0.05; See table 2 for environmental variable descriptions and table 4 for description of fish-community metrics; CA, correspondence analysis; p=Spearman’s rho; ---, not statistically significant] 

Environmental

variable

abbreviation

Correlation coefficient (ρ) and statistical significance

CA axes Fish-community metrics

CA 1 CA 2 omnivores spinsect catchrate simLiths

ρ pvalue ρ p-value ρ pvalue ρ pvalue ρ pvalue ρ pvalue

elevation 0.64 0.005 --- --- --- --- 0.54 0.018 --- --- 0.47 0.042

opencanopy 0.53 0.020 --- --- --- --- --- --- --- --- --- ---

embedded -0.48 0.036 --- --- --- --- -0.59 0.010 --- --- -0.56 0.015

LowBaseQ 0.61 0.008 0.54 0.019 --- --- --- --- --- --- --- ---

depth --- --- 0.49 0.032 --- --- --- --- --- --- --- ---

cobble --- --- --- --- 0.71 0.002 --- --- --- --- --- ---

cropland 

density

--- --- --- --- --- --- --- --- --- --- --- ---
42 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Axis 2

Axis 1

LUXCHR

AMBRUP

AMENAT

CAMOLI

CATCOM

CLIFUN

COTCAR

CYPGAL

CYPSPI

ESONIG

ETHBLE

ETHCAE

ETHDUR

ETHFLA

ETHKEN

ETHNIG

ETHRUF

ETHSIM

FUNOLI

GAMAFF

HEMFLA

ICTPUN LABSIC

LEPCYA

LEPMAC

LYTLIR

MICPUN

MICSAL

MOXDUQ

MOXERY

NOTAMB

NOTTEL PERCAP

PIMNOT

RHIATR

SEMATR

-0.5

-0.9

-1.4

0.5

0.9

1.4

1.9

2.4

-1.9

-1.9 0.5 0.9 1.4 1.9 2.4 -1.4 -0.9

Appendix 2. Correspondence analysis biplot illustrating the relation among fish communities for 20 sites in the Eastern

Highland Rim Ecoregion.

14

18 19

16

20

11 13 7 15

8

3

5

4

1 2

6

10

12 9

17

7 SAMPLING SITE AND NUMBER

EXPLANATION

BARRENS

DISSECTED TABLELANDS

MOULTON VALLEY

SUGGESTED SUBGROUPS WITHIN THE

EASTERN HIGHLAND RIM ECOREGION

Note: Site numbers are identified in table 1. Fish-species abbreviations are identified in table 7. The location of the sites (based on site scores)

along each ordination axis specifies the location of the site relative to the axis. Each axis is a linear combination of multiple variables,

where sites located near one another have similar characteristics and those located far apart have dissimilar characteristics. Subgroup colors

correspond to Ecoregion map on figure 2.
Appendix 3 43

Appendix 3. Fish species and the number of individuals collected at 20 sites in the Eastern Highland Rim Ecoreigon—Continued

Family Common name Scientific name Site number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

Amblyopsidae Spring cavefish Chologaster agassizi 0 0 0 0 1 0 0 0 0 0 0 0 0 0 Atherinidae Brook 

silverside

Labidesthes 

sicculus 

0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Catostomidae White sucker Catostomus commersoni 2 1 0 0 4 1 0 0 0 1 0 0 0 0 

Creek 

chubsucker 

Erimyzon 

oblongus

0 0 0 0 0 0 0 0 1 0 0 0 0 0 

Northern hog 

sucker 

Hypentelium 

nigricans

4 11 7 9 26 4 10 19 21 31 2 13 24 4 

Spotted sucker Minytrema 

melanops

0 0 0 4 0 0 1 0 0 1 0 0 1 0 

Black redhorse Moxostoma 

duquesnei 

0 0 0 4 9 0 0 0 19 2 0 0 0 0 

Golden 

redhorse 

Moxostoma 

erythrurum

0 1 0 0 3 0 1 1 10 16 0 0 0 0 

Centrarchidae Rock bass Ambloplites rupestris 0 1 53 0 9 0 2 27 0 0 1 20 0 0 

Redbreast 

sunfish 

Lepomis 

auritus

0 0 0 0 0 0 0 0 0 6 0 0 68 16 

Green sunfish Lepomis 

cyanellus

7 25 0 23 83 13 8 20 97 24 37 29 32 24 

Warmouth Lepomis 

gulosus

2 2 0 2 0 15 4 2 3 6 5 0 1 20 

Bluegill Lepomis macrochirus 44 26 3 99 2 30 57 24 62 109 13 10 20 74 Longear sunfish Lepomis megalotis 66 1 0 9 0 20 99 47 14 39 50 23 58 167 Redear sunfish Lepomis 

microlophus

0 0 0 0 0 2 0 0 0 3 3 0 1 0 

Hybrid sunfish Lepomis spp. 0 0 0 0 0 2 6 0 7 0 1 2 0 0 

Appendix 3. Fish species and the number of individuals collected at 20 sites in the Eastern Highland Rim Ecoreigon[Station identification numbers are listed in table 1]
44 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

Alabama and Tennessee, 1999

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, Family Common name Scientific name Site number

1 2 3 4 5 6 7 8 9 10 11 12 13 14 

Centrarchidae

(cont.)

Smallmouth 

bass 

Micropterus 

dolomieu

0 0 0 0 1 0 0 0 0 0 0 0 0 0 

Spotted bass Micropterus 

punctulatus

0 0 0 0 0 0 1 0 0 0 0 4 0 0 

Largemouth 

bass 

Micropterus 

salmoides

1 0 0 0 0 1 5 6 13 4 2 1 2 5 

Black crappie Pomoxis 

nigromaculatus

0 0 0 0 0 0 4 0 0 0 0 0 0 0 

Cottidae Banded sculpin Cottus 

carolinae 

111 58 0 5 75 64 0 20 72 11 36 78 9 1 

Cyprinidae Largescale 

stoneroller 

Campostoma 

oligolepis

6 45 30 129 259 3 152 670 180 85 32 411 25 3 

Rosyside dace Clinostomus 

funduloides

0 27 0 0 1 0 0 0 1 0 0 0 0 0 

Whitetail 

shiner 

Cyprinella 

galactura

0 0 65 0 6 0 0 7 48 0 0 0 0 0 

Spotfin shiner Cyprinella 

spiloptera

0 2 0 0 0 0 0 9 0 0 0 0 0 0 

Streamline 

chub 

Erimystax 

dissimilis

1 0 0 0 0 0 0 0 0 0 0 0 0 0 

Flame chub Hemitremia 

flammea

9 2 0 0 0 10 0 0 1 0 0 0 0 0 

Striped shiner Luxilus 

chrysocephalus

0 3 3 1 48 4 20 111 248 32 19 75 41 5 

Scarletfin 

shiner 

Lythrurus fasciolaris

0 1 29 1 46 1 44 121 63 0 245 83 153 144 

Ribbon shiner Lythrurus 

fumeus

0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Mountain 

shiner 

Lythrurus 

lirus

1 0 0 0 0 0 0 0 0 0 0 0 0 0 

Bigeye chub Notropis 

amblops

0 0 0 0 2 0 31 95 3 0 0 0 0 0 

Appendix 3. Fish species and the number of individuals collected at 20 sites in the Eastern Highland Rim Ecoreigon—Continued
Appendix 3 45

Family Common name Scientific name Site number 1 2 3 4 5 6 7 8 9 10 11 12 13 14 

Cyprinidae 

(cont.)

Bigeye shiner Notropis 

boops 

0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Rosyface 

shiner

Notropis 

rubellus 

0 0 0 0 5 0 0 0 0 0 0 0 0 0 

Telescope 

shiner 

Notropis

telescopus

0 0 0 0 90 0 0 0 0 0 0 0 0 0 

Mimic shiner Notropis 

volucellus

0 0 0 0 59 0 0 0 0 0 0 0 0 1 

Bluntnose 

minnow

Pimephales 

notatus 

0 0 2 0 2 0 3 15 22 3 53 0 5 10 

Blacknose dace Rhinichthys 

atratulus

0 0 0 0 0 1 0 0 7 1 0 1 0 0 

Creek chub Semotilus 

atromaculatus

0 2 0 0 0 0 0 0 2 0 0 0 0 0 

Fundulidae Northern 

studfish 

Fundulus 

catenatus

0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Blackstripe 

topminnow

Fundulus 

notatus 

0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Blackspotted 

topminnow

Fundulus 

olivaceus 

0 0 0 0 0 0 4 1 0 0 8 4 6 20 

Ictaluridae Black bullhead Ameiurus 

melas 

1 0 0 0 13 0 0 0 0 0 0 0 0 0 

Yellow 

bullhead

Ameiurus 

natalis

0 0 0 0 0 0 1 0 5 1 1 0 1 2 

Channel 

catfish

Ictalurus 

punctatus

0 0 0 0 0 0 0 0 0 0 0 0 0 1 

Slender 

madtom 

Noturus exilis 0 0 0 0 0 0 0 0 0 0 0 6 48 3 

Lepisosteidae Longnose gar Lepisosteus osseus 0 0 0 1 0 0 0 0 0 0 0 0 0 0 Esocidae Chain pickerel Esox niger 0 0 0 0 0 0 0 0 0 0 8 1 1 0 Percidae Greenside 

darter 

Etheostoma 

blennioides

0 0 0 0 15 0 0 13 0 0 0 0 0 0 

Appendix 3. Fish species and the number of individuals collected at 20 sites in the Eastern Highland Rim Ecoreigon—Continued
46 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

Alabama and Tennessee, 1999

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, Family Common name Scientific name Site number

1 2 3 4 5 6 7 8 9 10 11 12 13 14 

Percidae 

(cont.)

Slackwater 

darter 

Etheostoma 

boschungi

0 0 0 0 0 0 0 0 0 0 1 0 0 0 

Rainbow darter Etheostoma 

caeruleum

43 50 0 11 17 0 1 24 28 0 15 27 14 0 

Black darter Etheostoma 

duryi 

23 7 120 50 37 12 5 16 29 6 27 25 48 2 

Fantail darter Etheostoma 

flabellare

0 0 0 0 56 0 0 0 0 0 0 0 0 0 

Stripetail darter Etheostoma 

kennicotti

0 0 0 0 0 0 0 0 0 0 5 0 0 1 

Blackfin darter Etheostoma 

nigripinne 

0 0 1 0 0 4 7 1 11 0 0 0 1 0 

Redline darter Etheostoma 

rufilineatum

0 0 0 156 25 0 0 143 0 0 0 0 0 0 

Snubnose 

darter 

Etheostoma 

simoterum

0 0 0 0 17 0 7 56 4 0 0 0 51 0 

Logperch Percina 

caprodes

23 15 0 1 0 0 0 2 0 11 0 2 11 3 

Dusky darter Percina 

sciera

0 0 0 0 0 1 0 1 0 0 0 0 1 0 

Sauger Stizostedion 

canadense

0 0 0 0 0 0 0 0 0 0 0 0 0 0 

Petromyzontidae Unidentified lamprey Ichthyomyzon sp.

3 0 0 0 5 0 0 0 0 0 0 0 0 0 

Least brook 

lamprey 

Lampetra 

aepyptera

0 0 0 0 0 1 1 0 0 0 4 1 0 0 

Poeciliidae Western 

mosquitofish 

Gambusia 

affinis

0 0 0 0 0 8 0 1 1 0 9 0 0 21 

Salmonidae Rainbow trout Oncorhynchus mykiss

0 2 0 0 0 0 0 0 0 0 0 0 0 0 

Scianidae Freshwater 

drum 

Aplodinotus 

grunniens

0 0 0 1 0 0 0 0 0 0 0 0 0 0 

Appendix 3. Fish species and the number of individuals collected at 20 sites in the Eastern Highland Rim Ecoreigon—Continued
Appendix 4 47

Appendix 4. Fish species, tolerance class, trophic guild, and reproductive group for species collected at 20 sites 

in the Eastern Highland Rim Ecoregion—Continued

Common name Scientific name Tolerance class Trophic guild Reproductive 

group

Rock bass Ambloplites rupestris IN TC

Black bullhead Ameiurus melas TO OM

Yellow bullhead Ameiurus natalis TO OM

Freshwater drum Aplodinotus grunniens IN

Largescale stoneroller Campostoma oligolepis OM

White sucker Catostomus commersoni TO OM L

Rosyside dace Clinostomus funduloides IN SP L

Banded sculpin Cottus carolinae IN

Whitetail shiner Cyprinella galactura IN

Spotfin shiner Cyprinella spiloptera TO IN

Steelcolor shiner Cyprinella whipplei IN

Streamline chub Erimystax dissimilis IN SP L

Creek chubsucker Erimyzon oblongus IN IN L

Chain pickerel Esox niger TC

Greenside darter Etheostoma blennioides SP L

Slackwater darter Etheostoma boschungi HI SP

Rainbow darter Etheostoma caeruleum SP L

Black darter Etheostoma duryi HI SP L

Fantail darter Etheostoma flabellare IN SP

Blueside darter Etheostoma jessiae IN SP L

Stripetail darter Etheostoma kennicotti SP L

Blackfin darter Etheostoma nigripinne SP

Redline darter Etheostoma rufilineatum SP L

Snubnose darter Etheostoma simoterum SP L

Spring cavefish Forbesichthys agassizi

Northern studfish Fundulus catenatus HI SP L

Blackstripe topminnow Fundulus notatus IN

Blackspotted topminnow Fundulus olivaceus IN

Western mosquitofish Gambusia affinis TO IN

Flame chub Hemitremia flammea IN L

Northern hog sucker Hypentelium nigricans HI IN L

Unidentified lamprey Ichthyomyzon sp.

Channel catfish Ictalurus punctatus OM

Brook silverside Labidesthes sicculus IN

Least brook lamprey Lampetra aepyptera HB

Longnose gar Lepisosteus osseus TO TC

Appendix 4. Fish species, tolerance class, trophic guild, and reproductive group for species collected at 20 sites 

in the Eastern Highland Rim Ecoregion

[Classifications based on unpublished Tennessee Valley Authority data; *, non-native species; IN, insectivore; TO, tolerant; OM, 

omnivore; L, Lithophil; HI, headwater intolerant; SP, specialized insectivore; TC, piscivore; HB, herbivore]
48 Response of Fish Communities to Cropland Density and Natural Environmental Setting 

in the Eastern Highland Rim Ecoregion of the Lower Tennessee River Basin, 

Alabama and Tennessee, 1999

Common name Scientific name Tolerance class Trophic guild Reproductive 

group

Redbreast sunfish* Lepomis auritus IN

Green sunfish Lepomis cyanellus TO IN

Warmouth Lepomis gulosus IN

Bluegill Lepomis macrochirus IN

Longear sunfish Lepomis megalotis HI IN

Redear sunfish Lepomis microlophus IN

Striped shiner Luxilus chrysocephalus TO OM L

Warpaint shiner Luxilus coccogenis HI SP L

Scarletfin shiner Lythrurus fasciolaris SP L

Ribbon shiner Lythrurus fumeus TO SP L

Mountain shiner Lythrurus lirus HI SP L

Spotted sucker Minytrema melanops IN L

Black redhorse Moxostoma duquesnei IN IN L

Golden redhorse Moxostoma erythrurum IN L

Smallmouth bass Micropterus dolomieu TC

Spotted bass Micropterus punctulatus TC

Largemouth bass Micropterus salmoides TC

Bigeye chub Notropis amblops HI SP L

Bigeye shiner Notropis boops IN SP L

Rosyface shiner Notropis rubellus SP L

Telescope shiner Notropis telescopus IN SP L

Mimic shiner Notropis volucellus SP L

Slender madtom Noturus exilis IN SP

Rainbow trout* Oncorhynchus mykiss IN

Logperch Percina caprodes SP L

Dusky darter Percina sciera SP L

Bluntnose minnow Pimephales notatus OM

Black crappie Pomoxis nigromaculatus TC

Blacknose dace Rhinichthys atratulus IN L

Creek chub Semotilus atromaculatus TO IN

Sauger Stizostedion canadense TC L

Appendix 4. Fish species, tolerance class, trophic guild, and reproductive group for species collected at 20 sites 

in the Eastern Highland Rim Ecoregion—Continued