the response of stonefly and mayfly populations to total
TRANSCRIPT
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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
0
0.1
0.2
0.3
0.4
0.5
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0.7
0.8
0 5 10 15 20 25 30
Perc
en
tag
e o
f E
+P
Total P (u/L)
Phosphorus vs. Percentage of E+P