Bryant Impact of Insect Herbivores on Growth of Exotic & Invasive Plant Species Analysis – Description
Step 1:
Read the study on insect damage to plants from various types seen below (How does insect herbivore damage compare for native, exotic, and invasive plant species?)
How does insect herbivore damage compare for native, exotic, and invasive plant species?
Featured scientist: Elizabeth Schultheis from Michigan State University
Background
Insects that feed on plants, called herbivores, can have big effects on how plants grow. Herbivory can change the size and shape of plants, the number of flowers and seeds, and even which plant species can survive in a habitat. A plant with leaves eaten by insect herbivores will likely do worse than a plant that is not eaten. Plants that naturally grow in an area without human interference are called native plants. When a plant is moved by humans to a new area and lives and grows outside of its natural range, it is called an exotic plant. Sometimes exotic plants become invasive, meaning they grow large and fast, take over habitats, and push out native species. What determines if an exotic species will become invasive? Scientists are very interested in this question. Understanding what makes a species become invasive could help control invasions already underway and prevent new ones in the future.
Hypothesis
Because herbivory affects how big and fast a plant can grow, local herbivores may determine if an exotic plant thrives in its new habitat and becomes invasive. Elizabeth, a plant biologist, is fascinated by invasive species and wanted to know why they are able to grow bigger and faster than native and other exotic species. One possibility, she thought, is that invasive species are not recognized by the local insect herbivores as good food sources and thus get less damage from the insects. Escaping herbivory could allow invasive species to grow more and may explain how they become invasive.
Experiment
To test this hypothesis, Elizabeth planted 25 native, 25 exotic, and 11 invasive species in a field in Michigan. This field was already full of many plants and had many insect herbivores. The experimental plants grew from 2011 to 2013. Each year, Elizabeth measured herbivory on 10 individuals of each of the 61 species, for a total of 610 plants. To measure herbivory, she looked at the leaves on each plant and determined how much of each leaf was eaten by herbivores. She then compared the area that was eaten to the total area of the leaf and calculated the proportion leaf area eaten by herbivores. Elizabeth predicted that invasive species would have a lower proportion of leaf area eaten compared to native and noninvasive exotic plants.
The Dataset:
Download the data set: Dataset 2 herbivory in native exotic and invasive plant species.xlsx (attached below)
Species name: scientific name of each species included in the study
Plant type: whether the plant species is clasified as either native, exotic or invasive.
Year of data: the year when data for that plant was collected.
Proportion leaf herbivory (%): The percentage of leaf damage observed for each plant
Step 2:
Select one of the following graphs that correctly and appropriately plots the data from the spreadsheet in a way that can answer the hypothesis.
Step 3:
Open a Word document.
Step 4: (In the Word document)
Question: What is the main question from the study? Must use your own words, do not copy from the quiz or from the data description. It must be in question form. This is the title of the assignment.
Approach: In no more than five sentences, describe the experiment or the procedure used to obtain the data. Must use your own words, do not copy from the dataset. This is NOT a methods section or an introduction. It should not be numbered or written as instructions. Instead, fill this section in as if someone taking the same lab and with the same knowledge asked you what you did in lab today.
Graph: Copy the graph you selected (Command+C) above and paste it (Command+V) onto Word.
Results: The results must contain no more than three sentences summarizing the TRENDS in the results. Explain what the data in the graph show. This is a brief description of what the graph shows.
Discussion: in five or fewer sentences explain what the results mean in relation to the hypothesis of the study. If there are several possibilities, explain which you think is most likely and why. Critically, this section must contain the answer to the question of the study and indicate whether the hypothesis was correct or incorrect, or an acknowledgement if the data is inconclusive to answer the question.
The post Bryant Impact of Insect Herbivores on Growth of Exotic & Invasive Plant Species Analysis first appeared on .
