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Abstract -
Using the electro-fishing method we will sample fish from two streams, Harkers Run and Collins Run, which have been equally affected by the recent drought. We will statistically analyze the diversities of fish populations in each and compare to previously collected data in order to come to a conclusion about the relationship of environmental stress on disturbed habitats. If damaged streams are more affected by environmental stress, then by extension damaged ecosystems around the world will be less likely to cope with environmental stress. This implies that we must be proactive in helping nature recover from our disturbances.
Introduction -
We want to explore the way that drought affects streams that are damaged, compared to healthy streams. Our hypothesis is that the diversity of both streams will be statistically lowered due to the drought, but that Collins Run, a stream that was affected by human development, will be statistically more damaged than Harkers Run, which flows through a preserve. This will indicate that an ecosystem, once damaged, is not able to weather environmental stress as well as undamaged streams even if the degradation has more or less come to a halt.
These are our specific predictions:
- Rainfall significantly affects the diversity in an ecosystem. Due to the drought this year, the fish diversity in both Collins and Harkers Run should be less compared to a non-drought year.
- As found in the Fishbusters study, the diversity in a damaged
ecosystem is considerably less than in a relatively undisturbed ecosystem (2001). This should still hold true for this year.
- We predict that the diversity in the disturbed stream, Collins Run, will be more affected by this yearÕs drought than the undisturbed stream, Harkers Run, due to human influence.
The purpose of our experiment is to measure the effects the recent drought has had, using diversity as an indicator of health. We will compare the data we collect to the research done by the Fishbusters lab group in 2001, which acts as our control, since it gives us the streamsÕ health when there was no drought. The Fishbusers lab group measured the diversity of fish populations in Collins and Harkers Run and then compared the data between the two. Their original hypothesis was that human urbanization affects fish diversity. Their hypothesis was statistically accurate. It is now one year later and we intend to use their data to measure the effects of the drought on the streams. Specifically, we want to test the divirsity of each to establish whether this environmental stress has affected both systems equally. We think that this is an interesting experiment, and it involves a lot of hands-on natural science, which is what we wanted to explore. Also, the discussions in class have made us all curious about whether the planet will be able to recover or not from what humans have done.
Relevance of Research Question -
The book Riparian Ecosystem Recovery in Arid Lands says this of ecosystems that have been disturbed; ÒOnce the causes of decline are addressed, the ecological resiliency . . . takes over, often leading to the dramatic recovery of the system.Ó (p 26) But is this really true? Can we really continue to depend on nature to recover time and time again from our repeated abuse?
Although our hypothesis is that vulnerable ecosystems do not survive as well as their unaffected counterparts, other scientists, as demonstrated by the earlier quote, donÕt necessarily agree. One theory, called the dynamic equilibrium model, suggests that human disturbance can sometimes increase diversity. As described in Freshwater Ecology, the theory indicates that while the killing of important species within an ecosystem reduces the diversity, it also allows species that were outcompeted by these species to thrive. Disturbance, in this case, decreases diversity only if it exceeds the ability of species to recover. This theory can be taken into account if our diversity results turn our differently than we had anticipated.
One thing that everybody agrees on is that ecosystems are damaged, and continue to be damaged further. Freshwater Ecosystems, which features a description of the ecological crisis of streams, states that 40 percent of streams are too degraded to fully support aquatic life. The Missouri river has seen an 83% drop in commercial catch in 1947, according to Imperiled Waters, Impovershed Future. In North America there is 950 known freshwater species, 2% of which are extinct and 37% or which are imperiled. These losses are due to habitat degradation and the introduction of exotic species.
Most scientsists seem to be of the opinion that these lands would recover perfectly, if human beings would just leave them alone. However, we could find no empiricle evidence for this assumption. If our hypothesis is proven, it will indicate that this is not the case.
The relevance of our research is becoming increasingly important. Damaged ecosystems are increasing in number, and studies such as ours can be used to asses the capabilities of these ecosystems to recover from the damage that have sustained through pollution and other human activities. Streams that are damaged start off with a disadvantage compared to healthy streams, and then fall further and further behind as environmental stresses (like drought) set in. It's almost like a "natural selection" of ecosystems, and a damaged stream is less fit, and doesn't survive. If this is true, what about places like Costa Rica or the coral reefs? Can we just leave them to recover on their own, or is this setting them up to die? Furthermore, many habitats are dependent on individual species, should these species die the habitat will become damaged. On top of this effect many habitats are interdependent, the effect on one habitat can be felt through out them all. (Abramovitz, p. 5-10) This indicates that it is necessary to protect ecosystems at all costs.
Materials and Methods -
Experimental Design:
Our design, which features a random sampling technique, avoids bias by using statistics to arrive at a conclusion. We try to capture every fish in the section of stream, which even if impossible should result in a good representative population. This is why we use the electroshocker as opposed to any other method, such as nets, to capture the fish; it guarantees a large, evenly distributed sample of the stream as a whole. After that it is a matter of mathematics to validate or disprove our thesis, because either the populations are statistically comparable in the face of the drought, or they are not. We are fairly confident in our method, both because of the previous study that we are working with, and because of the input of Hays and the approval of Dr. McCullem.
Materials:
To do this experiment we will need not only an electric fish shocker, but also:
rubber boots, full-leg and knee-high,
multiple fish nets,
water testing kits for each of the planned tests, including sampling jars and chemicals, and
Assorted buckets for sorting the fish.
In theory there would not be a large list of materials associated with this lab because so much of the work is statistical or revolves around drawing conclusions. These supplies should all be available from the science lab.
Procedure:
Since the Fishbusters study was done the year before, we had a very good idea of how our experimental design was going to work out in advance. This was very useful, as was having Hays and Dr. McCullum to help us.
- The first thing is to establish land use patterns as they affect each stream. This entails examining what has been done in the watershed of each stream in the past; to prove that our undisturbed stream is indeed undisturbed and to examine what kinds of processes might have contributed to the disturbance of Collins Run.
- Also, we will explore the affects of the drought in Ohio by researching the precipitation in the past year.
- We test two different streams for our survey, an undisturbed stream and a disturbed one. We hope to test each stream twice, to really reproduce the Fishbusters results. The first thing that we will do is perform some basic chemical testing such as dissolved oxygen and nitrogen to establish the health of the stream.
- Then, everybody gets into the equipment, which in our case, besides warm clothing, was long wader pants. These were attached to rubber boots and were actually quite important because they kept us from being shocked.
- The person who is going to wear the shocker gets dressed, keeping the weight on their hips. This is a difficult job because if the person leans too far forward the engine floods. When itÕs all loaded up, we start the engine. We use 1.5 amps to stun but not kill the fish.
- The people who are acting as netters get on either side of the shocker, although not in front of him due to the risk or stirring up the silt.
- The person, who is the shocker, keeping the wire tail in the water, sets the net in the water and activates the shock. As it beeps it sends an electric pulse into the water. The person sweeps the shocker from side to side, stirring up the water and going around the rocks and banks.
- The netters attempt to net all of the fish that come to the surface, attracted and shocked by the electro-shocker. While it may not be possible to collect every fish, in the attempt to do so we should get a good representative random sample.
- The collected fish are deposited into buckets for later sorting.
- The shocker and his netters move up the stream slowly, trying to gather samples from each section. This is important because a length of stream contains different depths and temperatures, as well as different concentrations of rocks and refuse. We are trying to sample the stream as a whole.
- After the sampling is finished, everybody gets out of their gear and the identification process begins. The fish are first sorted according to species (this is where DonnaÕs help is invaluable) and then counted. Several factors that determine the species of fish are the color, body shape, the mouth type, features of the fins, and the arrangement and appearance of scales. Our results are included, see table.
- The fish are released back in the stream when data collection is complete. Electroshock should not kill the fish, although a small percentage of fatalities can occur.
This process is to be repeated in the other sample environments until each target area has been tested. Then, using statistical analysis such as the Shannon-Weiner test and a simple T-test, the data is compared both to each other and to the previous year. We need statistics to measure the difference between the streams this year and last year to prove that the drought has affected the streams, and compare the differences to prove our hypothesis that the damaged stream has fared worse in a difficult year. We will be using the Spearman Rack Test in Statview to illustrate the abundance of species. The Index of Dominance will be used to compare the health of the streams. Unhealthy creeks will have only a few or single species in domination as opposed to a more evenly dispersed population concentration. The Index of Similarity will be used to compare the how similar our tests sites are. Shannon Index of General Diversity will be used to calculate the biodiversity of the populations within the two creek systems.
Our presentation to the class will focus mainly on statistical analysis, and we may have the class crunch some numbers. Besides that, we will present a slideshow of the streams and of us collecting data. The presentation will also include a discussion of environmental degradation as it applies to streams and to ecosystems at large.
Timeline:
- On October 15th, at approximately 8:15 we started our first sampling at Collins Run. We worked until approximately 11.
- Our next sampling time is set for October 21st, also a Monday morning at 8. It will test Harkers Run.
- Hopefully, during that same week we will do our second sampling for both streams.
- On Wednesday the 23rd of October we return to the streams to do necessary tests and document the streams fully in digital photography.
- After this point, all time until the project is turned in is devoted to research. We plan to spend the week following this second sampling researching the land use around the streams and running our statistical tests, to draw conclusions.
- On October 24th we present to the class! YouÕre probably reading this right now!
- The final project is turned in before the end of the semester. Wild party scheduled for this week.
Literature Cited -
Abramovitz, Janet N., Imperiled Waters, Impoverished Future: The Decline of Freshwater Ecosystems, Worldwatch Institute, 1996 ¨¢ We will use this source for information about environmental degradation and other such information.
Brezonik, Patrick L. et. al., Freshwater Ecosystems, National Academy Press: Washington, D.C. 1996 ¨¢ We will use this source to see what we should expect to find in the streams.
Briggs, Mark K., Riparian Ecosystem Recovery in Arid Lands: Strategies and References, University of Arizona Press, Tuscon, TX 1996 ¨¢ About the recovery of damaged ecosystems, which is what the stream is.
Cairns, John, Functional Testing of Aquatic Biota for Estimating Hazards of Chemicals, American Society for Testing and Materials, Ann Arbor, MI 1989 ¨¢ Further information regarding chemical tests.
Dodds, Walter K., Freshwaater Ecology: Concepts and Environmental Applications, Academic Press, London UK, 2002 ¨¢ Information on freshwater ecology and information on electrofishing
Downes, Barbara J., Monitoring Ecological Impacts: Concepts and practice in flowing waters, Cambridge University Press: 2002 ¨¢ Information on human effects on flowing water
Hill, Ian R., Freshwater Field Tests for Hazard Assessment of Chemicals, CRC Press, London, England 1994 ¨¢ Used for information on the various testing techniques we want to use
Isom, Billy G. ed., Rationale for Sampling and Interpretation of Ecological Data in the Assessment of Freshwater Ecosystems, American Society for Testing and Materials, 1986 ¨¢ Information on gathering and interpreting data for our experiment
Lind, Owen T., Handbook of Common Methods in Limnology, The C.V. Mosby Company, Saint Louis 1974 ¨¢ This has information about how the streams healths' can be measured
Myers, Wayne L., Survey Methods for Ecosystem Management, Wiley-Interscience Publication, New York, NY 1980 ¨¢ Describes the various sampling systems and statistical analysis that we could use.
Trautman, Milton B., The Fishes of Ohio, Ohio State University Press, Columbus, OH 1981 ¨¢ Will be useful for identifying the various fish
William, D. Dudley, The Ecology of Temporary Waters, Timber Press: Portland, Oregon 1987 ¨¢ This source describes the affects of drought on both temporary and more permanent bodies of water.
Online Resources and Journals:
Weekly Palmer Drought and Crop Moisture Data Products Explanation, Palmer Drought Data , 9/8/02
JSTOR Journal of Applied Ecology, jstor.org , 9/8/02
Journal of Fish Biology, ohiolink journals , 9/8/02
Microsoft Terraserver Imagery, terraserver.homeadvisor , updated daily
Also the fishbusters study, which can be found on the sylabus!
This is our first data table, collected by us from Collins Run on October 14th. As you can see, there were A LOT of fish in such a small section of creek. The fish were identified by us along with the expert guidance of Dr. Donna McCullem. There is still a lot of research to be done in order for us to interprete this data. Within a few weeks, we should have four tables like this to really evaluate each section of each creek that we are investigating.
(please excuse the technical difficulites that arose from posting - we did the best we could)
Variety - Population in sample
Stoneroller 50
Blunt-nosed Minnow 39
Creek Chub 27
Blacknosed Dace 35
Silverjaw Minnow 5
White Sucker 7
Golder Redhorse Sucker 1
Spotfin Shiner 74
Emerald Shiner 1
Orangethroat Darters 7
Green Sunfish 2
Bluegill Sunfish 1
Stripped Shiner 21
Total 270
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