Elephant Ear Hypothesis

Effect of Elephant Ear on Growth of Water Tupelo

Research Question:

How does the growth of the Invasive Species Colocasia escuelenta (Elephant Ear) affect the growth of Water Tupelo (Nyssa aquatica) in Bluebonnet Swamp?

Variables:

Independent: Presence of Invasive Species Colocasia escuelenta

Dependent: Presence of Water Tupelo (Nyssa aquatica)

Background:

Colocasia escuelenta is an invasive species primarily present in wetlands, swamps, and along shorelines. This species is typically grown for aesthetic purposes, but has spread to southern wetlands. In these wetlands, it spreads densely in clumps and blocks sunlight and takes nutrients from other native species (Capital Area Plant Society). The elephant ear are characterized by their large leaves that block sunlight from

other desired native species (IFAS Center for Aquatic and Invasive Species). Students at Louisiana State University have been working to eradicate the presence of Colocasia escuelenta in Bluebonnet Swamp. The species takes hold in this area because it is a humid wetland. This species can also be referred to as “Wild Taro” on the invasive species list given by Wildlife and Fisheries (Keating, 2017). Elephant ear crowds and blocks sunlight for other low-lying plants. The Water Tupelo (Nyssa aquatic) is a native species commonly found in Bluebonnet Swamp (iNaturalist, 2012). Contrary to Colocasia escuelenta, this species is not invasive. The focus of this experiment will be to use quadrat sampling to determine whether there is a positive, negative, or no relation between the two species.
My interest in this topic originated from a lesson regarding using quadrat sampling to determine the relationship between species, specifically focusing on predator and prey and other types of biological associations. I realized during this lesson that quadrat sampling and chi-square analysis could also be used to determine the relationshiop between plant species, and potentially explain the relationship of invasive species and native species. My father, being a landscape architect, has done work in Bluebonnet Swamp, which piqued my interest in this particular conservation area.
For safety purposes, I will wear protective clothing and gloves to prevent interaction with poisonous plants.

I will wear gloves and cover my whole body to prevent interaction with potentially harmful elements of the environment. I will also be very careful to touch as little as possible in the environment so as not to disturb the wildlife.

Hypotheses:

If Colocasia escuelenta is present, then Nyssa aquatica will not be, because Colocasia escuelenta is an invasive species that will likely dimish the presence of native species such as Nyssa aquatica. Therefore, the two species will have a negative association.

Null: There is no association between the species Colocasia escuelenta and Nyssa aquatic.
Alternate: There is an association between the species Colocasia escuelenta and Nyssa aquatic.

Methodology:

Sample Size:

100 quadrat samples were taken at random in Bluebonnet Swamp. This area was chosen due to its humid climate and it’s wetlands.

Data Collection
1. Create a data table like so:

Colocasia escuelenta present
Colocasia escuelenta absent
Nyssa aquatica present

Nyssa aquatic absent

2. Place quadrat in a random position within the boundaries of the

swamp.
3. Determine whether within the boundaries of the quadrat Colocasia escuelenta is present or absent.
4. Record one tally in the table under “Colocasia escuelenta present” if the species is present within the quadrat, and record one tally in the table under “Colocasia escuelenta absent” if absent.
5. Determine whether within the boundaries of the quadrat Nyssa aquatic is present or absent.
6. Record one tally in the table under “Nyssa aquatica present” if the species is present within the quadrat, and record one tally in the table under “Nyssa aquatica absent” if absent.
7. Repeat steps 2-6 99 more times and record data in table.
8. Use chi-square analysis to determine if there is a significant relationship between the two species.