Effects of Human Land Use on Fish Population (THE FISHBUSTERS)

This topic submitted by Grace Schneider, Marta Ralston, Amanda Higley, Kristen Mandish at 2:26 am on 10/26/01. Additions were last made on Friday, April 19, 2002. Section: Cummins

Environment Effects on Fish Population in Miami Creeks

Abstract

We are studying how human land use effects fish population and diversity in nearby creeks. We are collecting data concerning the different species of fish and the total number of fish present in Collins Run and Harkers Run on two different occasions with Dr. Donna McCullum. We are utilizing the technique of “fish shocking” in order to catch fish in two areas on each creek so that we can count how many species of fish are present in each area and how many total number of fish are in each area. These numbers will help us in deciding whether or not each creek has a healthy amount of fish diversity. After taking all our data we will use the Shannon-Weaver Index and the Simpson Index to decide which test sites have better biodiversity. There have been many other studies run in various parts of the world in which this same shocking technique, the Shannon-Weaver Index, and the Simpson Index were used when studying fish diversity and how human development affects it. At this point in our study we have already found that Collins Run has less fish diversity than Harkers Run does, though Collins Run has a much larger fish population than Harkers Run. Since Collins Run is the creek near more human urbanization these findings supports the part of our hypothesis that states “human urbanization will cause the fish populations to be less diverse”. However, they disprove the part of our hypothesis that states “human urbanization will cause the total fish population to be smaller.

Introduction

For our semester research project we are studying the effects that human urbanization has on fish populations. Our project is localized since we are conducting tests in two creeks, Collins Run and Harkers Run, which wind through Miami's campus. The main question we are testing is "how does the environment around the creek affect the fish populations?" We believe that the more human urbanization there is present near the creek, the smaller and less diverse the fish population will be. We decided to research this topic after going on the creek walk up to the Bluffs. We quickly realized that we all enjoyed walking through the creek and the serene setting the creek provided. We are also interested in the chance to learn how we affect the natural environment and hope to find ways that we can prevent human damage through urbanization. We also hope to find correlations between our research results and results obtained in other international research. In working towards this goal we plan to answer the specific questions of “what characteristics define a healthy fish population” and “what elements are needed for a healthy stream ecosystem.” We believe these questions will aid us in drawing conclusions which will help us solve our main problem. In the end we believe this project will help us achieve a greater appreciation for the environment we live in here at Miami, as well as at home, now and in our future.

Relevance of our Research Question

After conducting background research we found two equations in the web page Species Diversity which will help us evaluate the biodiversity of our test sites We will utilize these two equations, the Shannon-Weaver Index and the Simpson Index, when deciding if the diversity of the fish populations in Collins Run and Harkers Run is healthy.

The Shannon-Weaver Index “measures the average degree of uncertainty (synonymous with diversity) of predicting the species of a given individual picked at random from a community” (Ourso). If a population only has one species it is rated with a value of 0, but if a population has many species with a few individuals of each species it receives a high value. The equation used in the Shannon-Weaver Index is:

equation from Species Diversity

The Simpson Index is “based on the probability of drawing a pair of individuals of the same species” and is best used when “the relative degree of dominance of a few species in the community is of primary interest, rather than the overall evenness of the abundance of all species”. The value “varies inversely with heterogeneity (i.e., index values decrease [or increase] as the diversity increases [or decreases])” and it “can be regarded as a measure of dominance concentration”(Ourso). The equation used in the Simpson Index is:

equation from Species Diversity

Calculating the biodiversity of our test sites is not the only factor that past studies have shown as important when studying how human urbanization effects fish population though. We must also take into consideration many of the different elements of the stream’s ecosystem. Most of the characteristics we are noting which affect the stream’s ecosystem were also sampled in a study in North American Journal of Fisheries Management. In this study they measured “bank width, stream width, depth, velocity, clay substrate, silt substrate, sand substrate, fine gravel substrate, coarse gravel substrate, rubble-cobble substrate, boulder substrate, cover for fish shading, minimum and maximum bank heights, and bank erosion.” (Simonson, Lyons, Kanehl, 607). We will be taking data on all of these characteristics except “bank width”, “cover for fish shading, minimum and maximum bank heights, and bank erosion.” Another study noted in Landscape Ecology also touched on the importance of substrates, velocity, and depth variability, as well as, expressing an importance in the presence of pools, riffles, and bends in the stream (habitat variety). These added characteristics are also being taken into consideration in our study as we make sure that each test site has a habitat which contains pools, riffles, and bends. Yet another characteristic of importance noted by Environmental Toxicology and Ecotoxicology is the fact that natural population can fluctuate by month, season, and year. These fluctuations can be dramatic and result from normal changes in climate and environment. This statement shows how we must keep track of the weather (mainly rainfall) since it may effect our results.

Facts which show how the land use outside of the stream effects the fish in the stream are stated in articles in Landscape Ecology and Fisheries. Landscape Ecology states that the absence of organic litter (i.e. leaves from nearby plants) reduces the heterogeneity of depth, substrate, and current velocity thus causing streams with little structural complexity. Adding this fact with the already stated fact that habitat variety is necessary in a healthy stream ecosystem shows that human urbanization which gets rid of plants near streams will cause the entire aquatic ecosystem to “lose” its variety and no longer be healthy. The threat of human urbanization is even further magnified with the fact stated in Fisheries that “93% of declining fish taxa are suffering from habitat loss/destruction” (Williams,7) and the causes of this destruction are often “physical and chemical degradation” such as urban and agricultural encroachment (Williams, 8)

There are also many facts in past studies which we find interesting that relate to our study. A fact we found interesting in Fisheries is that the nine most diverse families of freshwater fish are minnows, perches, suckers, billifishes, livebearers, bullhead catfishes, salmon/trout, Mexican livebearers, and sunfishes”(Williams, 7). We thought it was neat because even though we were testing in a small stream we found fish in two, minnows, and sunfishes, of the nine categories. We found an interesting study very similar to our study in which a group of students in Maryland studied the “long term changes in stream due to land use” by building models of streams. We also found interesting projects that were similar to our project in previous years in natural systems, such as "The effect of landscape on streams and their behavior as corridors" and "Erosion on the creek banks (the mudslides)." And lastly, a fact stated in Biological Monitoring of Fish helps make a connection between our study of the fish population and the entire aquatic ecosystem. This fact is that “fish play a central role in biomonitoring because they are the top of the food chain in most aquatic ecosystems, and their presence shows other organisms are in the ecosystem.” This statement relates fish to the larger picture of the entire stream ecosystem. Our research relates to the larger question of "how well do humans need to monitor their land use around the world?" We hope to contribute the knowledge of how much our land use affects aquatic life, even in a small community such as Oxford. This information may then be combined with other studies to expand our knowledge of the interactions between humans and the environment on a large scale.

Materials and Methods

The first step in our experiment is to go out and find two places in each creek which are all very similar in temperature, water current, water depth, and creek width. With the creek areas acting as our constant variable we will be able to focus more on the variable of human land use. After we choose our testing sites we plan to make maps of the areas surrounding the creeks. These maps will allow us to compare the urbanization around the creeks and be a good visual aid for those looking at our results. We are doing our field work with Dr. McCullum and her shocking technology. We will use the shocking technique in each area and count the number of fish and different species in each test area. This is the data we will use in our statistical analysis in statview. In our testing we won't be taking some factors such as pollution (due to lack of chemical testing ability), light and shade (since the lighting will change during the day this won't make a difference), or other animal influence (because it would be nearly impossible to track all nearby animal life). Below is a link to the data table that we are using during our experiment.

Data Sheet

We believe that our data will be statistically sound because all of the numbers that will be added and manipulated will be in equal units. We won't know for sure if this belief is true until after all our data is collected though. We are making sure that most of the environmental factors, such as temperature, water depth, creek width, water current, and testing area length, are constant in an attempt to eliminate all biases. To make sure the class’ data is trustworthy we will put the students in groups of more than one person for each task (so there will be more than one person counting each thing ensuring accurate results) and compare the numbers each person gets to make sure there is a clear corrolation. We believe our collection methods will be adequately shown because we are documenting our field testing in photos and videos which we will be showing to the class.

The "fish shocker" will be our most important tool since it is necessary in order to count and classify the different types of fish living in each area. In our attempt to make sure that all testing areas are similar we will use a thermometer to check water temperature, and a meter stick to measure the stream depth, stream width, and the test area’s length. We will also be using a ping pong ball, string, and stopwatch to test the water's velocity by timing how long it takes the ping pong ball to float down the stream from one point marked by string to another point marked by string. Throughout our testing we will also be utilizing maps of the area surrounding both creeks to determine the amount of urbanization and its proximity to the creeks. An important tool we will be using is a catalogue of freshwater fish and Donna McCullum’s knowledge to classify the different types of fish.

In the student generated lab the students will be measuring all the environmental characteristics present around our testing areas (water depth, average creek width, current, water temperature, creek bed composition). After dividing the students into groups of two or three we will give half of the class the tasks of checking the environmental characteristics at one testing while the other half of the class tests another site. This will be done simultaneously with half of the class at Harkers Run and the other half at Collins Run. After we have collected all the data each half of the class will compare all the measurements from their area to check accuracy. We won't be asking the students to process any data because they won't be testing all four sites. We will simply check to make sure their results correlate with the other measurements taken at their test site.

Time Line

October 6th - we will collect maps of the creek area and search for similar sections to test.
October 8th - we will meet with Dr. McCullum about the shocking technique and set up dates to use the equipment
October 13th, and 27th - we will meet and hopefully be able to test the 6 different areas we have chosen (weather and equipment permitting)

Bibliography

Environmental Toxicology and Ecotoxicology found at http://www.bio.hw.ac.uk/edintox/enviro.htm

Maryland Virtual High School Stream Modeling Project http://www.nehs.org/pages/streamproject.shtml#Project%20Description

Ourso, Bob. Species Diversityhttp://marisa.aquabio.swt.edu/ecology/notes/spdiversity/spdiversity.html

Hocutt, Charles H., and Jay R. Stauffer Jr. Biological Monitoring of Fish. Lexington, MA: D.C. Heath and Company, 1980.

Williams, Cindy Deacon Fisheries. “Substainable Fisheries Economics, Ecology, and Ethics”

Simonson, Timothy D., Lyons, John, and Kanehl, Paul D. North American Journal of Fisheries Management Vol. 14. “Quantifying Fish Habitat in Streams: Transect Spacing, Sample Size, and a Proposed Framework.” 1994

Roth, N.E., J.D. Allan, and D.L. Erickson. Landscape Ecology. Vol. 11. “Landscape Influences on Stream Biotic Integrity Assessed at Multiple Spatial Scales.”

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