Benthic Macroinvertebrate Assemblages in Flint River, Indian Creek and Flint Creek Watersheds in North Alabama- Preliminary Study

R. Ward, L. White, A. Bohlman and T. TsegayeDepartment of Plant and Soil Science, Alabama A&M University

P.O. Box 1208, Normal, AL 35762

METHODS (Cont’d.)

Dip Net – Both sides of the stream bank were sampled for aquaticinsects using 10 jabs of dip net along the stream within the sampling site.Samples were combined for collections on each side of the stream.

Leaf Pack – Leaf packs were collected from each half of the streaminto a composite sample (300-500 g wet weight). Leaf packs provide

suitablehabitat and nutrition for a variety of macroinvertebrates. Each collected leafpack was hand-picked for clinging invertebrates.

Kick Net - Three riffles were sampled with a 1-m kick net. Thesubstrate was disturbed approximately 3 meters upstream of the net. The invertebrates were handpicked after each kick.

Sampling SitesThe general geophysical characteristics of the collection sites canopy

cover (%), riparian vegetation, stream disturbances, etc. were noted.Field parameters recorded include stream depth (cm), water temperature(°C), pH, turbidity (FAU), total dissolved solids (ppm) and dissolved oxygen (mg/L). All macroinvertebrates were initially preserved in 75% ethylalcohol, brought back to the laboratory, sorted, identified to family, and

placed in 90% ethanol in glass vials.

Parameters For this report, bioassessment was based on percent (%) EPT for each

sampling site and for all watersheds combined. Percent chironomids andsimuliids were measured similarly. Other parameters (e.g., total taxa, diversity indices, etc.) will be used in subsequent data analyses.

LITERATURE CITEDU.S. EPA. 2006. Rapid Bioassessment Protocols for use in Streams and Wadeable Rivers:

Periphyton, Benthic Macroinvertebrates, and fish. http://www.epa.gov/owow/monitoring/rbp/index.html

Abstract

Benthic macroinvertebrates are excellent indicators of water pollution such as turbidity and nutrient loads. The assessment of aquatic biodiversity is widely used to strengthen continuing measures of water quality in north Alabama. This preliminary study was conducted to determine taxa richness (total number of taxa) and composition of aquatic insects occurring in Flint River, Indian Creek and Flint Creek. For this report, bioassessment was based mainly on the relative abundance of EPT and chironomid [percent Ephemeroptera-Plecoptera-Trichoptera (%EPT) and percent chironomids]. EPT are known to be highly sensitive to increasing perturbations; increase in their abundance suggest improved water health. The occurrence and dominance of chironomids, on the other hand, may indicate organic impairments of streams. Twenty seven families have been identified in our sample collections suggesting the rich diversity of biotic components in the watersheds under study. In this study, spring-summer aquatic insect samplings were done at monthly intervals in three locations along each tributary using surber, dip net, kick net and leaf pack methods. In addition, gastropod presence in the watersheds was also recorded. The sampling sites also represent the diverse riparian zones and land use of the surrounding areas. Our preliminary results showed high dominance of Ephemeroptera over stonefly and caddisfly populations in all watersheds. Chironomids and simuliids comprised the majority of the Dipterans collected. Likewise, Elmidae (riffle beetles) has a strong presence in all watersheds. Riparian and stream characteristics were described for each sampling location.

INTRODUCTION

Flint River, Indian Creek and Flint Creek are major tributaries to theTennessee River which supplies drinking water and provides recreation areas to residents of Madison and other counties in north Alabama. The quality of water draining from these watersheds is of prime importance to the public. Benthic macroinvertebrates vary in their sensitivity and tolerance of pollutants occurring in bodies of water. These organisms respond to long term impairments of stream water. Unlike chemical water parameters which are reflective of water condition at time of sampling, population levels of aquatic fauna respond to long term effects due to their stabilized water environment. Thus, as bioindicators, aquatic insects are excellent and reliable determinants of the general health of streams and rivers. Members of the orders Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies) are intolerant of pollutants; their relative abundance indicates good water quality. Midges and blackflies [both are in the order Diptera (flies)] are tolerant of pollution; their occurrence in high numbers is indicative of water impairment.

Table 1. Description of sampling sites.

Sample Sites Watershed Site Location Description

1. B.W. Road

2. 3 -Forks

3. FR on Hwy 72

4. Providence Main

5. Farrow Road

6. Old Madison

Pike

7. Lacon, AL

8. Bankhead

N.F.

9. Neel, AL

Flint River

Flint River

Flint River

Indian Creek

Indian Creek

Indian Creek

Flint Creek

Flint Creek

Flint Creek

Mostly agricultural, variable riparian widths, moderate canopy cover, high siltation.

High residential, wide riparian widths, too wide for complete canopy reach, remnants of old bridges

Mostly agricultural, expanding residential developments, public access accumulates trash, complete canopy, mixed substrate

On new greenway space off of poorly contained community development, stable riparian area, large snags throughout reach

On new greenway space through high residential area. Thin riparian area, highly shaded, mostly cobble bottoms

South of IC Greenway and current construction, large riparian buffers, balanced ratio of riffles, pools, some bedrock

In bottom hardwood forested/wetland, sandy bottoms, many snags and embankments, very low flow during dry season

Within established preserve wilderness area, ephemeral flow, well shaded by canopy, mix sandy and cobble substrate

Near some residential and wetlands, small intermittent stream, sandy mud bottom, previously channelized, high (>2.5 m) banks

Identified FamiliesNumber of Individuals

Percent%

Ephemeroptera: Heptageniidae, Ameletidae, Baetidae,

Caenidae, Ephermerillidae, Empididae 365 29.70%

Diptera: Chironomidae,Tipulidae,Tabanidae,

Simuliidae, Dixidae, Athericidae 219 17.82%

Trichoptera: Hydropsychidae, Philopotamidae,

Polycentropodidae, Psychomyiidae, Leptophlebiidae 193 15.70%

Coleoptera: Psephenidae, Elmidae 166 13.51%

Odonata: Coenagrionidae, Gomphidae, Aeshnidae, Calopterygidae, Libellulidae 141 11.47%

Gastropoda: N/A 106 8.62%

Plecoptera: Perlidae 39 3.17%

Total 1229 100.00%

METHODS

Study Watersheds – Flint River, Indian Creek and Flint CreekThree sampling sites, each 100 m long reach, were selected for each

watershed. For Flint River , the sites were on Hwy 72, Buddy Williams Road, and 3 Forks. For Indian Creek, Old Madison Pike, Farrow Road, and Providence Main were chosen. Lacon, AL, Neel, AL, and the Bankhead National Forest were selected for Flint Creek.

Sampling MethodsEach site per watershed was sampled monthly. Sampling was based on

EPA Rapid Bioassessment Protocol’s (RBP’s) multi-habitat methods (USEPA 2006). Macroinvertebrates were collected from a variety of microhabitats using different techniques. All sampling methods were begun downstream, moving up the reach to minimize disturbance.

Surber – Each site per watershed was divided into 3 sections with riffles along the length of the stream from which three samples were collected. Each sample was a composite of three sub-samples obtained by rubbing substrate (gravel and cobbles) for 1 minute to dislodge aquatic insects. Insects were individually picked using forceps or camel’s hairbrush from the mesh.

Allison at work

North Alabama watersheds

Top Eleven Families Found in All Watersheds

14%

14%

13%

10%10%

8%

8%

7%

7%

6% 3%

Elmidae HeptageniidaeHydropsychidae SnailsChironomidae “Unknown” Ameletidae BaetidaeSimuliidae CoenagrionidaeCaenidae

Fig. 1. Dominant families in watersheds combined.

Table 2 . Major groups collected in study areas.

Fig. 5. Simuliid mass from Flint River

SUMMARY

A total of 27 families were collected in all watersheds combined; top 9 included Heptageniidae, Elmidae, Hydropsychidae, Chironomidae, Ameletidae, Baetidae, Simuliidae, Coenagrionidae and Caenidae.

Indian Creek (Madison Pike) had the highest % EPT compared to other watersheds; however, this watershed (Providence Main) also harbored the highest number of chironomids.

Based on relative EPT abundance (% EPT) and low numbers of chironomids as bioindicators of pollutants, Flint River (Hwy 72) has the highest water quality of all watersheds under study.

Top 6 families account for 53.18 %; top 11 families account for 84.24%.

RESULTS

Each of the sampling sites is described in Table 1. On the Flint River, collection sites were near agricultural lands and expanding residential rural developments; most effluents were from adjacent agricultural farms. Indian Creek is situated in heavily populated urbanized sections of the City of Huntsville; two sites on this watershed bordered green space areas. Urban sprawl and sedimentation contribute significantly to the deterioration of water quality in this tributary. Flint Creek is a designated EPA cleanup site; it is heavily channelized through agricultural pasture lands but two of the collection sites are located in hardwood forested/wetlands. All of these reaches are intermittent; their flow slowed, developing into shallow pools during the dry season.

Twenty seven families in 7 orders were represented in our composite collections (combined watersheds) (Table 2). Among EPT, Ephemeroptera dominated other groups at 29% of total individuals collected (Figs. 1-3); families Heptageniidae and Hydropsychidae (Trichoptera) led the group in abundance across watersheds. Stoneflies were practically absent in the study sites; Plecoptera was represented by only one family (Perlidae) at 3.17%. Caddisflies (Trichoptera) had a healthy presence in the watersheds at 15.70%. Although combined EPT dominated all other insect groups, Diptera (17.82 %) closed in second to mayflies in abundance. Chironomids ranked fourth among top families in all watersheds suggesting organic stream impairment. Indian Creek (Providence) topped all other sites for number of chironomids. The site is in the center of a massive urban sprawl; adjacent areas are currently undergoing expansive business and residential development. The xylophagous riffle beetles (Elmidae) occurred in all watersheds. With Heptageniidae, Elmidae ranked first (at 14%) among top 11 families in the all watersheds (Fig. 1). Simuliids were predominant in Flint Creek (Fig. 4), occurring in moderate numbers elsewhere.

Chironomidae & Simuliidae Totals & Percentages

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50

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350

BWRD 3FKS FR72 ICPV ICFR ICMP Neel Lacon BKHD

Locations

Su

m F

amil

y T

ota

ls

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cen

t o

f T

ota

l In

div

idu

als

Sum of Chironomidae & Simuliidae Families %

Fig. 4. Total number and percent chironomids (bars) and simuliids

(line) in each sampling site.

Percent EPT Among All Watersheds

0.00

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BWRD 3FKS FR72 ICPV ICFR ICMP Neel Lacon BKHD

Locations

Perc

ent %

Fig. 3. Percent (%) EPT in all sampling sites.

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Flint Rive

r (BWRD)

Flint Rive

r (3F

KS)

Flint Rive

r (FR72

)

Indian

Creek (

ICPV)

Indian

Creek (

ICFR)

Indian

Creek (

ICMP)

Flint Cree

k (NEEL)

Flint Cree

k (La

con)

Flint Cree

k (BKHD)

Locations

Num

ber o

f ETP

fam

ilies

(Nos

.) &

ETP

(%)

Fig. 2. Total number of EPT collected

from each sampling site.

Flint River Indian Creek Greenway Flint Creek