Collaborators:
Maggie Weddle, Jaylyn Lowe, and Ian Hinkley
Introduction:
The purpose of this lab is to be able to further examine the biodiversity of a leaf litter sample from the Heritage High School trail outside and calculate it using Simpson's Index. The Simpson’s index measures the probability that two individuals randomly selected from a sample will belong to the same species. Biodiversity is the variety of life in a particular habitat or ecosystem. The method to calculate the biodiversity of an area is simpson’s index. There are two specific variables that biodiversity depends on; species richness and species evenness. Species richness is the number of species per sample. Species evenness is a measure of the relative abundance of the different species making up the richness of an area. To assist this experiment the main material of use is the berlese funnel. The berlese funnel is an apparatus used to extract living organisms, particularly arthropods.
Problem:
Why would we want to rate the amount of biodiversity in a location?
Hypothesis:
If a large sample of leaf litter is collected from the Heritage High School trail, then the sample will have a high level of macroinvertebrates.
Parts of this experiment:
- The independent variable is the location of leaf litter.
- The dependent variable is the diversity found in the leaf litter.
- There is no control group for this experiment
Materials:
- Stereoscope / Dissecting Microscope
- Berlese Funnel
- Leaf Litter
- Alcohol
- Source of Light
Methods:
- Collect a sample of leaf litter. Be sure to collect the entire layer down to the soil.
- Examine the sample and classify what you see the layer composed of.
- Place your sample into the Berlese Funnel under the light source. Place a small beaker of alcohol under the funnel. The hope is that small invertebrates will travel away from the light and fall into your alcohol.
- The next day, collect your beaker and examine the organisms you have collected under the microscope. You will need to calculate the number of each species you have, and identify them. Each person may work on a portion of the sample and put your numbers together. Use the identification pages to name each species.
- Use the information to calculate the diversity indices for your sample.
Data: |
Analysis |
Species: Springtail - 2, Mites - 16, Isopoda - 1, Dermaptera - 2, Isoptera - 1, Bladotera - 1, Diplura - 1
Total: 24 |
The data table shown above is all of the group's data samples from the lab. The groups calculated simpson’s index was .442. The simpson’s index diversity was .558. The Simpson's reciprocal index was calculated to be 2.26. Based off of these approximations, it is obvious that the biodiversity of the Heritage High School trail is high because the variable D was closer to 0.
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Pictures:
Conclusion:
In the Leaf Litter lab, the experiment was conducted to rate the biodiversity of a leaf litter sample from the Heritage High School trail. The hypothesis was if a large sample of leaf litter is collected from the Heritage High School trail, then the sample will have a high level of macroinvertebrates. The results reflected the hypothesis; the biodiversity of this experiment turned out to be high. In the sample provided there was 7 species found, making the species richness high. However, the species evenness of these species were not very evenly distributed.
A cause to make the organisms move away from the light and further into the funnel is because the light serves as an artificial sun and will naturally move away from it. In addition, the organisms move away from the light is because the light generates heat, creating a stimulation of the sun. Detritivores, is the majority of the organisms found in the leaf litter; they prefer cooler weather, so by creating an artificial heat source just as the sun, the detritivores will move away. This indicates the organisms like cooler and darker climates away from the sun.
One should suspect the biodiversity to be high because the species richness and species evenness was high; from the collected leaf litter 7 different species were found. This created a total of 24 macroinvertebrates found. The cause of this was due to a significantly high number of mites. Mites tend to live in large groups near trees, which incidentally this sample was collected, thus creating a large abundance.
An environmental scientist would need to take more than one measurement if one was calculating the biodiversity due to a higher probability of projecting an accurate results. In order to take samples from a large forest, one would have to take many samples from various parts of the forests to receive the highest accuracy. For instance, if the environmental scientist only collected data from one area that was healthy, one cannot conclude that the whole forest is healthy. Therefore the experiment conducted will be inaccurate. According to the European Environment Agency, the biodiversity of their forest ecosystems is faced with threats such as air pollution and climate change. Climate changes initially affects the range of tree species in the area. Due to the increased drought periods and warmer winters the forests are weakened. Some trees may have a higher timber yields, although genetic variety in regionally adapted forests is necessary in order for the trees to withstand any means of threats.
A cause to make the organisms move away from the light and further into the funnel is because the light serves as an artificial sun and will naturally move away from it. In addition, the organisms move away from the light is because the light generates heat, creating a stimulation of the sun. Detritivores, is the majority of the organisms found in the leaf litter; they prefer cooler weather, so by creating an artificial heat source just as the sun, the detritivores will move away. This indicates the organisms like cooler and darker climates away from the sun.
One should suspect the biodiversity to be high because the species richness and species evenness was high; from the collected leaf litter 7 different species were found. This created a total of 24 macroinvertebrates found. The cause of this was due to a significantly high number of mites. Mites tend to live in large groups near trees, which incidentally this sample was collected, thus creating a large abundance.
An environmental scientist would need to take more than one measurement if one was calculating the biodiversity due to a higher probability of projecting an accurate results. In order to take samples from a large forest, one would have to take many samples from various parts of the forests to receive the highest accuracy. For instance, if the environmental scientist only collected data from one area that was healthy, one cannot conclude that the whole forest is healthy. Therefore the experiment conducted will be inaccurate. According to the European Environment Agency, the biodiversity of their forest ecosystems is faced with threats such as air pollution and climate change. Climate changes initially affects the range of tree species in the area. Due to the increased drought periods and warmer winters the forests are weakened. Some trees may have a higher timber yields, although genetic variety in regionally adapted forests is necessary in order for the trees to withstand any means of threats.
Citations:
"Biodiversity and Forest Ecosystems in Europe." — European Environment Agency (EEA). European Environment Agency, n.d. Web. 10 Oct. 2014.
<http://www.eea.europa.eu/highlights/biodiversity-and-forest-ecosystems-in-europe-1>.
“Simpson Diveristy Index.” Offwell Woodland and Wildlife Trust. Available: http://www.offwell.free-online.co.uk/simpsons.htm
<http://www.eea.europa.eu/highlights/biodiversity-and-forest-ecosystems-in-europe-1>.
“Simpson Diveristy Index.” Offwell Woodland and Wildlife Trust. Available: http://www.offwell.free-online.co.uk/simpsons.htm