Yellow Bush Lupine Seedbank vs Fire Experiments

Fire Response

Each plant species has its own way or stimulating seed release. Some species require high temperatures from a fire in order to release their seeds.

EDU 3020 Lemon Clock	Young Scientists Club Set 10	Young Scientists Club Set 5	Student & Home Microscopes
Ages 8 and up	Ages 9-12	Ages 9-12	Ages 10 to Adult

Objectives/Goals

The objective of my project was to study how fire effects the seedbank of Yellow Bush Lupine (Lupinus arboreus). Yellow Bush Lupine is an invasive non-native plant found on the sand dunes of Humboldt County beaches. It is harmful to both the physical structure and plant ecology of the dunes. I wanted to find out if fire kills the seeds or helps them to germinate. If fire kills the seeds or prevents them from germinating this could be helpful because fire could be used as one way to remove Yellow Bush Lupine from the dunes.

Methods/Materials

A test box containing an artificial sand dune was constructed. Lupine seeds were buried at different levels in my sand box with a thermometer at each level. Branches, litter, and duff collected from beach dunes were placed on top of sand and burned. Temperatures were recorded at each level in the sand. Seeds were recovered and then incubated to determine germination rates.

Results

In the top layer of sand the temperature increased rapidly. In the lower levels the temperature stayed the same (as starting point) for a long time and only rose slightly after an hour or more. The results showed that most seeds in the shallowest layer (2") were killed by fire and that seeds buried deeper were not effected by the heat.

Conclusions/Discussion

A major problem with the physical removal of Yellow Bush Lupin from the dunes is that the large seed bank that Lupines produce remains to start new plants. My experiment showed that fire will kill the seeds in the top layer of the sand, and this could reduce the number of plants that grow and need to be pulled from the dunes. 3rd party contributor