Niemes Elementary School, Artesia, California
6th Grade
This project was started in the fall of 2007, when a 12 x 6 meter field was fenced and left un-mowed and allowed to grow.
Materials List:
Procedure:
1. Students are taught about ecological succession, how plant communities replace each other over time. I show a self-created PowerPoint presentation to this end.
2. As part of the presentation students start learning weed (plant) identification. We then visit the succession garden and attempt to identify the plants with in a survey ring. The students are also supplied with field guides that help them identify each plant.
3. Next, we do our complete plant survey using self-built point-data collection tables. Each student team records 28 data points designated by the crosshatchings of the strings on the table. The location of the table is recorded based on the corner fence post. Students lineup their eyes to where the strings meets with 2nd row of strings below and look straight to the ground, the first plant they see they record has the data point. We collected our data in the first week of June both years.
4. The data is then gathered and tables are produced using excel. The data from the first two years is available below, as are samples of the collection and data sheets and a species guide.
Results & Conclusions:
There were some pretty dramatic species density changes from year-to-year. The dominant plant in 2007 was clover but in 2008 it dropped below 10%. The dominant plant in the 2nd year, which covered more then 35% of the field, was Bremuda grass. This grass was almost non-existent in the 1st year.
Another interesting discovery was that two plant species went locally extinct in the 2nd year. The Dill and Filarees were probably both too small to compete with the dense ground cover that grew over the year. This growth is evident in the fact that the bare ground reported dropped from 7.14% in year 1 to 0.44% in the 2nd year. This was also the cause of the disappearance from the record of the Knotweed in year 2. However, there was knotweed in the field it was covered by this tall 2nd year growth.
And finally, the appearance of the Cheat Grass is distinct. There was no evidence of this grass in year 1 and it grew to become the second most dominant plant in year 2. We predict that in the coming years that the cheat grass will continue to grow and by next year dominate the field. We decided this when we discovered why cheat grass got its name. It grows fast to out-compete other plants, produces a lot of seeds and then quickly dies, cheating resources from other plants and food from animals.
