• Students will be able to describe differences in flora between an area overrun by invasive species and one with native species.
• Students will understand how competition for resources is affected by invasive species through a quantitative species count.
• Students will learn how to measure percent cover and diversity of different species.
• Students will demonstrate how competition from invasive species leads to decreased diversity of species by quantitative methods.

• Douglas Fir forests are a natural ecosystem in the Pacific Northwest where the Halsey's ranch is located. Why do you think they might be willing to cut it down in favor of oak savanna? Think in terms of regional biodiversity.

The purpose of this activity is to have students calculate the percent cover and diversity of species in an area that has been overcome by English Ivy and one that hasn't (you may want to change the directions and the maps to represent species found in your own area, for instance Kudzu in the southeast has similar coverage patterns as English Ivy has in the Northwest). Diversity is the total number of plant species in an area while percent cover is how much of the land is covered by each species. Areas with higher diversity can provide for a richer ecosystem. However, since other factors such as rainfall and temperature also have an impact, diversity alone cannot account for ecosystem health. In this activity students will compare two squares from the same ecosystem.

Students may work in groups of 2 or 3.

Hand out the maps and grids (one set includes a copy of each map and 1 grid). Or, sign out a computer lab and download the photograps and grids as described above.

Have students:

1. 1. Place the grid over the map. Note that the grid provided is smaller than the photos. Students should place the grid so that it fits somewhere entirely on the map. Each group will place it slightly differently so that the have slightly different results. This is meant to simulate some of the conditions that students would encounter when working in the field. You can use this activity to discuss with your students how scientific research is conducted.
2. Look at each place on the grid where two lines cross and note which type of plant is there or if there is forest floor. Students can try to identify species if you want them to. Otherwise, the activity is written so that they just need to recognize the same species for counting.
3. Make a data table that shows how many occurrences of each species there are in the area represented (a meter square). See sample below.
4. Calculate the percent cover for each species. This should be the number counted divided by 25 (the total number of crosses).
5. Repeat for the second map.
6. You may want to have students make a bar graph or a pie chart showing percent cover for each of the two maps.
7. Answer the analysis questions on the Student Instructions Handout.

(note: this is only an example)

Plants present on the native forest floor map include: bracken fern, trailing raspberry, vine maple, ducksfoot, and clematis.

The only plant present in the Ivy map is ivy.

Answer key to Analysis Questions:

1. In the ivy desert, ivy accounted for most of the cover. Amounts might vary slightly by group depending on placement of grid.
2. Percent cover measures how much sun each species receives.
3. It's called an ivy desert because not much is growing there besides ivy. Some groups also use the term 'ivy wasteland' since deserts do have their own rich biodiversity. The term is to imply the sterility and monotony that occur when a single species dominates an area. (www.noivyleague.com)
4. Almost no forest floor is visible in the ivy desert meaning that other species haven't got a chance to gain a foothold unless they can grow without sunlight.
5. Ivy will continue to grow and kill trees and other native plants in the area. The park may become a giant ivy desert.
6. Ivy reduces the biodiversity of the area.
7. If there is lower diversity of flora, then fauna will start to decrease too. Some organisms are dependant on particular plant species; if these disappear then the other organisms will disappear too (see video clip on the Karner Blue Butterfly).
8. The "ecological services" provided by biodiversity include the supply of oxygen to the atmosphere, water purification, the prevention of floods and soil erosion, nutrient recycling, and pollination. Nearly half of all medicines used today originally came from wild organisms. (from the Sierra Club)
9. Remove the ivy, replant native species, stop human interference with the ecosystem.
10. Counting each plant is too time consuming. If a scientist makes these kinds of measurements, he or she will get the basic picture although they might miss a few details.

• Using ecologist's tools, students will compare diversity in the field.
• Students will understand how greater plant biodiversity leads to greater animal biodiversity.
• Students will learn how to fight back against native species.

• What are some strategies that allow non-native species to outcompete the native species?
• How do you think you might fight back against non-native species?
• Think of at least two methods, other than biological controls, that people might use to try to get rid of invasive weeds? Are these better or worse than biological controls
• Why do we have to be very careful before releasing a new insect into the ecosystem.

• Research an invasive species from your area. You might start by looking at the Nature Conservancy's Wildland Invasive Species Program which has a map of the US that will help you identify some invasive species in your area. It also has a pretty comprehensive index of species and control methods.
• Or check out this site produced by the Forest Park Ivy Removal Project for information about invasive species and ideas for research projects.
• Conduct research on biodiversity and farming practices. How do monocultures (single species crops) affect biodiversity? How does genetic engineering affect biodiversity?