by Mason Luck ’16

Ecosystems are complex. Between thousands of years of symbiotic relationships a given system becomes stable. That is not to say that each facet is perfect, but it works. When one piece of the system is thrown off the whole system will inevitably feel the effects and could collapse as a result. Invasive species throw off the natural balance. Centaurea stoebe, otherwise known as the spotted knapweed, is an invasive species of flora close to home. It affects natural systems by outcompeting natives, causing all sorts of problems. Fields of wild grass can be taken over completely by Centaurea in effect disrupting livestock feeding grounds. In the more natural sense it may completely replace the native species, taking out the first level of a stable trophic chain. If you knock out the base of a building it is bound to collapse, much like the base of the food chain.

The goal of my research is to discover particulars about how Centaurea survives-especially as it pertains to substrates and watering schemes. Thus far I am working with roughly 715 Centaurea seedlings. The substrates I am using are sand and soil. I plan to analyze how fast/how well plants grow in each substrate, giving me a glimpse into their competitive abilities in a nutrient poor and nutrient rich environment. If they can grow in sand they may have an advantage in utilizing a substrate that is hard to be used by others. If they grow in soil, they still show that they can compete in an environment fit for other flora. The plants will receive three different watering treatments: low, medium, and high. Depending on survival and growth we can see if Centaurea has the competitive advantage of being able to withstand harsh conditions, as well as normal and high watering conditions. Once the plants are reproductively active the amount of seeds they produce will show us how well they are able to adjust to each treatment. If they produce many seeds they did very well, as they were able to devote energy to making seeds instead of growing more roots or leaves to counterbalance our treatements.

Mason with a sample of Centaurea stoebe collected locally from the High Bridge Trail.