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The Response of Stonefly and Mayfly

Populations to Total Phosphorus Levels

Research Conducted by: Elise Huntley and Lexie Huntley

Introduction

Methods Regression Chart

GIS Map

Conclusion

Acknowledgments

Trend line showing the inverse relation between the Percentage of Ephemeroptera

and Plecoptera (E+P) versus Total Phosphorus (ug/L) concentration

Results

As participants in the Vermont EPSCoR Streams Project, our

methods were as follows:

•Sampled total phosphorus in streams across Vermont twice a

month (Figure 1).

•Sent the samples to be tested at University of Vermont (UVM).

•During the sampling period, macroinvertebrates were collected

from four different riffles in each stream.

•Selected the different specimens using a random sampling

method.

•Identified the macroinvertebrates using the Guide to Aquatic

Invertebrates of the Upper Midwest, a Stereoscope, and the

assistance of the Biology Department at St. Michael’s College.

•Designated total phosphorus as our independent variable;

Percentage populations of Ephemeroptera and Plecoptera

macroinvertebrates were designated as our dependent variable.

•Retrieved data from eight (8) other stream sites. (Figure 1).

•Averaged the percentage of Ephemeroptera and Plecoptera

versus the total phosphorus average of each stream.

•Compared the quantities of Ephemeroptera and Plecoptera to the

total phosphorus (ug/L) in each stream site using the correlation

coefficient and the R2 value.

•Tested our hypothesis by using a regression chart and

trophic bar graph (Figures 2 and 3).

We decided to test whether increasing amounts of Total

Phosphorus present in Vermont streams will have an inverse effect

on the populations of Mayfly (Ephemeroptera) and Stonefly

(Plecoptera) Macroinvertebrates. We chose Ephemeroptera and

Plecoptera because they are plentiful in Vermont streams, easy to

collect, and, due to their need for dissolved oxygen, they respond

quickly to excessive total phosphorus levels. Studies by the State of

Vermont and others show that total phosphorus is directly related to

the levels of oxygen in the water.1 Phosphorus is a necessary

nutrient for all life forms. When phosphorus increases, plant growth

immediately responds both in vitality and in the quantity of plants

themselves. The plants then compete with other aquatic life to use

the available oxygen in the water. Thus, the greater the phosphorus

levels, the lower the oxygen levels that are available for

macroinvertebrates to breathe. Additionally, plants at the water’s

surface prevent the wind from agitating the water. The amount of

oxygen absorbed into the water is then further decreased. The

result is that too much phosphorus makes it difficult for

Ephemeroptera and Plecoptera macroinvertebrates to survive. We

hypothesized that since Vermont has urban areas, agricultural

areas and national forests, we would find streams with a wide range

of total phosphorus concentrations (see Figure 3). This makes it

possible to test our hypothesis that oxygen sensitive

macroinvertebrates will respond inversely to phosphorus

concentrations.

We would like to thank:

Christine Colella, Claire Huntley, Jason Saltman and Richard Huntley for helping with the fieldwork, collecting

the macroinvertebrates, writing the report, the graphs, the posters and so much more. The Grinold and the

Child families for allowing us access to the stream sites, Professor Declan McCabe and his students for

helping us ID the macroinvertebrates, Lexie Haselton for the GIS Map and the data, and everyone at UVM,

St. Michael’s College and Vermont EPSCoR Streams Project for all they do to make the streams project a

success.

Our results strongly supported our hypothesis. We performed

a correlation test to discover if there was a relationship between our

data sets of macroinvertebrates and total phosphorus. A correlation

test indicates whether there is a relationship between data sets. The

closer the correlation coefficient is to either positive one or negative

one, the stronger the relationship is between data sets. Our

correlation coefficient was -0.87397. The negative sign means that

one of our data sets decreased as the other data set increased. Our

tests showed a strong inverse relationship between our data sets

showing that our selected macroinvertebrates decreased as total

phosphorus increased. We then tested our data using regression

analysis to see if one data set was dependent on the other data set.

Our regression analysis value was 0.76383 which is, statistically,

extremely close to one. Thus, our analysis shows a strong inverse

dependant relationship between Phosphorus and the presence of

Ephemeroptera and Plecoptera in Vermont streams. Through these

tests, we verified our observations that an increase in Total

Phosphorus does decrease the total populations of Ephemeroptera

and Plecoptera macroinvertebrates.

Trophic Chart

In conclusion, our study shows, through statistical analysis,

that the total populations of Ephemeroptera and Plecoptera are

strongly dependant on changes in Total Phosphorus. Ephemeroptera

and Plecoptera macroinvertebrates only moderately react to total

phosphorus in 0-14 u/L which is a healthy range of nutrients for plant

and aquatic life. Once the presence of Phosphorus increases beyond

the 14 u/L, plant growth explodes and consumes too much of

available dissolved oxygen. The result is that Ephemeroptera and

Plecoptera macroinvertebrates correspondingly decrease due to lack

of oxygen. Our study indicates that the presence of Ephemeroptera

and Plecoptera in aquatic environments is a reliable indicator of the

health of Vermont Streams. Future experiments might include the

relationship between macroinvertebrates and chlorophyll, dissolved

oxygen, turbidity or water temperatures to better understand whether

the presence Ephemeroptera and Plecoptera in streams is a reliable

indicator of clean water from different perspectives.

Ephemeroptera

And

Plecoptera

References

Phosphorus Oxygen

Oligotrophic : Having a deficiency of plant nutrients that is usually accompanied by

an abundance of dissolved oxygen.5

Mesotrophic : Reservoirs and lakes which contain moderate quantities of nutrients

and are moderately productive in terms of aquatic animal and plant life.6

Eutrophic : Characterized by an abundant accumulation of nutrients that support a

dense growth of algae and other organisms, the decay of which depletes the

shallow waters of oxygen in summer. 7

Mayfly nymph – Siphlonurus typicus

Notice the gills and the long body. These

Mayflies are important to streams because

they are sensitive to oxygen. Mayflies are one

of the most important food sources for fish.

Mayflies move like dolphins and are very

strong swimmers.2

Stonefly nymph – Malirekus iroquois

Notice the two tails and the armored

body. Stoneflies move like turtles and

many stalk their prey. Stoneflies are

one of the most sensitive

macroinvertebrates to human

disturbance.4

0

10

20

30

40

50

60

70

80

Streams categorized into trophic levels comparing populationsof Ephemeroptera and Plecoptera and Total Phosphorus

from 2008 Data

Total Phosphorus (ug/L)

Average population of Ephemeroptera and Plecoptera/100

Oligotrophic

0-7 ug/L

Mesotrophic

7-14 ug/L

Eutrophic

>14 ug/L

Figure 1

Figure 2

Figure 3

Figure 4

Macroinvertebrates

Additional Information

References Continued

1 Vermont Agency of Natural Resources, Department of Environmental Conservation, Water Quality Division

(United States) [VTANR/VTDEC]. A Survey of Nation’s Lakes - EPA’s National Lake Assessment and Survey of

Vermont Lakes. Waterbury (VT): VTANR, VT DEC, Water Quality Division; 2009 Available from:

http://www.anr.state.vt.us/dec/waterq/lakes/docs/lp_VT_LakeSurvey_07-08.pdf

2 Richards C. Take Me Fishing [homepage on the Internet]. Alexandria (VA): Recreational Boating and Fishing

Foundation; 2008. [cited 2010 Apr. 7]. Available from: http://www.takemefishing.org/fishing/fly-fishing/fishing-

flies-lures/what-fish-eat. (stonefly and mayfly info)

3VanDyk J. BugGuide.Net [homepage on the Internet]. (IA): Creative Commons; 2009 Apr. 15. [cited 2010 Apr.

7]. Available from: http://bugguide.net/node/view/266381. (Mayfly image);

http://bugguide.net/node/view/263123 (Stonefly image)

4 Fore L S. Statistical Design [homepage on the Internet]. Seattle (WA): 1998. [cited 2010 Apr. 7]. Available from:

http://www.seanet.com/~leska/Online/Guide.html. (stonefly and mayfly info)

5 Merriam-Webster Online Dictionary. 2010.

Merriam-Webster Online. 7 April 2010. http://www.merriam-webster.com/dictionary/oligotrophic

6 Websters-Online-Dictionary. 2010. Webster's Online Dictionary: The Rosetta Edition. 7 April 2010.

http://www.websters-online-dictionary.org

7Dictionary.com Unabridged (v 1.1), Based on the Random House Unabridged Dictionary, © Random House,

Inc. 2006. http://www.dictionary.com

Carlson, R.E. and J. Simpson. 1996. A Coordinator’s Guide to Volunteer Lake Monitoring Methods. North

American Lake Management Society. 96 pp. Available from: http://dipin.kent.edu/trophic_state.htm

Ramey V. Plant Management in Florida Waters [homepage on the Internet]. University of Florida (FL): Center

for Aquatic and Invasive Plants, University of Florida, and the Invasive Plant Management Section of the Florida

Fish and Wildlife Conservation Commission; 2003. [cited 2010 Mar.]. Available from:

http://plants.ifas.ufl.edu/guide/trophstate.html.

Vermont EPSCoR Streams Project

109 Carrigan Drive, 120 Marsh Life Science, Burlington, VT 05405

Phone: 802-656-5467 www.uvm.edu/~streams/

Mayfly nymph – Siphlonurus typicus3

Stonefly nymph – Malirekus iroquois3

y = -0.0201x + 0.677R² = 0.7638

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Perc

en

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e o

f E

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Total P (u/L)

Phosphorus vs. Percentage of E+P