Leaf Litter Lab
Collaborators:
Emily Davis
Ellie Lupton
Caitlin Brennan
Devin Stafford
Laura
Introduction:
The lab was conducted in order to observe and measure the biodiversity of the old growth deciduous forest on the edge of Forestville and Rogers Road, beside Heritage High School. Understanding and rating the biodiversity of an ecosystem is important, as it's needed in order to understand the effects of surrounding human development as well as climatic and ecological changes. According to the National Wildlife Federation, "Biodiversity allows for ecosystems to adjust to disturbances like extreme fires and floods." Samples of leaf litter were extracted from the forest and deposited in homemade berless funnels to sit for several days under a heat lamp. The heat lamp forces the organisms to recede to the bottom of the funnel and fall through the gauze, and finally into a beaker of rubbing alcohol to trap and preserve them. The beaker’s contents were then observed under a microscope and recorded for examination by the class.
In the pre-lab, the Simpson's Index was used to determine that:
Sample 1 Index: .17 - Extremely diverse
Sample 2 Index: .25 - Very diverse
Sample 3 Index: .92 - Barley diverse
Problem: Identify the biodiversity index of the given forest and determine its overall biodiversity.
Hypothesis: If the leaf litter of the given forest is collected and observed, it will be concluded that the forest has limited to average biodiversity, given the unfavorable weather and cold season.
Parts of experiments:
Experimental group: Leaf litter samples
Independent variable: Location of leaf litter sample
Dependent variable: Biodiversity/contents of leaf litter
Materials:
Methods:
Data:
Collection date: February 11th, 2015, at 7:50 am
Location: Temperate forest on the edge of Rogers and Forestville Road, Wake Forest, NC
Type of community: Old growth deciduous forest
Emily Davis
Ellie Lupton
Caitlin Brennan
Devin Stafford
Laura
Introduction:
The lab was conducted in order to observe and measure the biodiversity of the old growth deciduous forest on the edge of Forestville and Rogers Road, beside Heritage High School. Understanding and rating the biodiversity of an ecosystem is important, as it's needed in order to understand the effects of surrounding human development as well as climatic and ecological changes. According to the National Wildlife Federation, "Biodiversity allows for ecosystems to adjust to disturbances like extreme fires and floods." Samples of leaf litter were extracted from the forest and deposited in homemade berless funnels to sit for several days under a heat lamp. The heat lamp forces the organisms to recede to the bottom of the funnel and fall through the gauze, and finally into a beaker of rubbing alcohol to trap and preserve them. The beaker’s contents were then observed under a microscope and recorded for examination by the class.
In the pre-lab, the Simpson's Index was used to determine that:
Sample 1 Index: .17 - Extremely diverse
Sample 2 Index: .25 - Very diverse
Sample 3 Index: .92 - Barley diverse
Problem: Identify the biodiversity index of the given forest and determine its overall biodiversity.
Hypothesis: If the leaf litter of the given forest is collected and observed, it will be concluded that the forest has limited to average biodiversity, given the unfavorable weather and cold season.
Parts of experiments:
Experimental group: Leaf litter samples
Independent variable: Location of leaf litter sample
Dependent variable: Biodiversity/contents of leaf litter
Materials:
- Leaf litter
- Alcohol
- Heat lamp
- Gauze
- Rubber band '
- Berless funnel (upside down recycled milk carton)
- Compound microscope
Methods:
- Collect a sample of leaf litter. (Collect entire layer down to the soil.)
- Set up berless funnel station with heat lamp above the funnel, with beaker of alcohol below.
- Place sample of leaf litter in berless funnel
- Place a small beaker of alcohol under the funnel
- In a chosen number of days, collect the beaker and examine the contained organisms under a microscope
- Record the organism types and numbers for class data
Data:
Collection date: February 11th, 2015, at 7:50 am
Location: Temperate forest on the edge of Rogers and Forestville Road, Wake Forest, NC
Type of community: Old growth deciduous forest
Data analysis:
Calculations using the Simpson's index reveal that the class data of leaf litter has a Simpson's index of .14, a Index of Diversity of .86, and a Reciprocal index of 7.14. The data, as compared to that of the fall's class data, displays a lack of biodiversity within the ecosystem. However, independently, the Simpson's index implies that the forest is in fact diverse. It can be concluded that this is due to the fact that the forest in the spring yielded less varieties of species than the fall, so the proportions of numbers to species make the two sets of data seem similar in diversity.
Conclusion:
The original hypothesis of the lab proved to have underestimated the diversity of the leaf litter, due on account of the discouraging weather. The organisms that live in this leaf litter habitat apparently thrive in damp, cool environments, as they moved away from the light source as it dried the upper layer of leaf litter. In addition, the severe heat and light from the lamp was physically harmful for the organisms, and it can be concluded that they are not normally exposed to direct sunlight. The biodiversity of this litter is high density, because the Index of Diversity was .86, and so was very close to 1, meaning high diversity density. However, in reality, an environmental scientist would need to take more that one sample in order to get a realistic measurement of the forest's biodiversity, as past data has shown that the biodiversity changes through seasons and weather. Taking samples throughout the forest at even distances may help the scientist get an idea of a larger forest. By understanding the method by which to determine diversity, as shown in this lab, scientists and surveyors are able to assess the impact of humans and development on an ecosystem, similar to the work of the National Wildlife Federation, which among other things, works to conserve the biodiversity of wildlife.
Citations:
"What Is Biodiversity? - National Wildlife Federation." What Is Biodiversity?National Wildlife Federation, n.d. Web. 26 Feb. 2015.
Calculations using the Simpson's index reveal that the class data of leaf litter has a Simpson's index of .14, a Index of Diversity of .86, and a Reciprocal index of 7.14. The data, as compared to that of the fall's class data, displays a lack of biodiversity within the ecosystem. However, independently, the Simpson's index implies that the forest is in fact diverse. It can be concluded that this is due to the fact that the forest in the spring yielded less varieties of species than the fall, so the proportions of numbers to species make the two sets of data seem similar in diversity.
Conclusion:
The original hypothesis of the lab proved to have underestimated the diversity of the leaf litter, due on account of the discouraging weather. The organisms that live in this leaf litter habitat apparently thrive in damp, cool environments, as they moved away from the light source as it dried the upper layer of leaf litter. In addition, the severe heat and light from the lamp was physically harmful for the organisms, and it can be concluded that they are not normally exposed to direct sunlight. The biodiversity of this litter is high density, because the Index of Diversity was .86, and so was very close to 1, meaning high diversity density. However, in reality, an environmental scientist would need to take more that one sample in order to get a realistic measurement of the forest's biodiversity, as past data has shown that the biodiversity changes through seasons and weather. Taking samples throughout the forest at even distances may help the scientist get an idea of a larger forest. By understanding the method by which to determine diversity, as shown in this lab, scientists and surveyors are able to assess the impact of humans and development on an ecosystem, similar to the work of the National Wildlife Federation, which among other things, works to conserve the biodiversity of wildlife.
Citations:
"What Is Biodiversity? - National Wildlife Federation." What Is Biodiversity?National Wildlife Federation, n.d. Web. 26 Feb. 2015.