by I Säumel, I Kowarik
Resource Type: Journal article
Source: Landscape and Urban Planning (2010) 94(3–4): 244-249
Grades: Middle School and High School
Not all nonnative species become invasive. What are some things that increase the invasiveness of plants? In this easy-to-understand study, seeds of different tree species were painted, dropped off a bridge into the Spree River in Berlin, and tracked to see how far downstream they would move. After only three hours, one quarter of the seeds were found 1,200 m from the start. This is much farther than they would travel in the wind. Rivers, therefore, are a potentially important factor in increasing the invasiveness of nearby trees.
Phenomena:
Invasive species
DCIs:
LS1.B: Growth and development of organisms
LS2.A: Interdependent relationships in ecosystems
LS2.C: Ecosystems dynamics, functioning, and resilience
LS4.C: Adaptation
LS4.D: Biodiversity and humans
Notes:
- Easy to understand experiment.
- Measures and compares movement of three seed types in urban river.
- Argues for avoiding nonnative species along rivers.
- Offers insight into secondary dispersal (primary dispersal here: seeds fall from tree and are carried by wind; secondary dispersal: they fall into river and are carried much farther)
Driving questions:
- What are some methods by which trees species spread? (wind, water, animals, etc.)
- Is the primary method of dispersal always the most important?
- What characteristics of seeds might make them more likely to spread?
- How does the physical environment affect the spread of species? Are there other landforms that might affect how species spread?
Topics: Ailanthus altissima (tree of heaven), dispersal, invasive species, natural selection, reproduction, and seed
Features: data table, line graph, p values, and regression lines