A dynamical systems approach to modeling growth, spread, and control of invasive watermilfoil.
Current project members: Diana White and Jonathan Martin (Clarkson University, Mathematics), Michael Twiss (Clarkson University, Biology), and Kyle Monette (Clarkson Mathematics Undergraduate). Work is completed in collaboration with the Norwood Lake Association (NLA).
Past project members: Isabel Dengos (MSc in Mathematics, Clarkson)
*Project funded by the NYS DEC through their invasive species irradiation program.
In September 2016, I started modeling biological invasions in my own backyard (literally!). In particular, I'm working to develop a model to study the spread and biological control of invasive watermilfoil, one of the most invasive aquatic plants in the US. The test site I'm looking at is Norwood Lake (where I live), a small reservoir located along the Raquette River in Upstate New York.
Invasive watermilfoil project on Norwood Lake, Upstate NY
Variable-leaf watermilfoil early June in Norwood Lake 2017 (Photo credit: Diana White). VLM begins growing in early/late spring, and depends on a variety of water conditions. As the season progresses (ending in early Fall), the plants out-compete most other native plants, to form a thick/dense canopy on the water surface.
Members of Clarkson and the Norwood community take advantage of a 12-foot drawdown to pull an 800 m^2 area of watermilfoil (photo credit: Michael Twiss)
The end result (photo credit: Michael Twiss). The milfoil collected from a hand harvest can be used as fertilizer for local farmer's fields. It's important to make sure that wet milfoil doesn't make it's way back into a water body, since small fragments can remain viable for extended periods of time, growing new roots and creating new plants/problems if introduced back into the water.
Variable-leaf watermilfoil early June in Norwood Lake 2017 (Photo credit: Diana White). VLM begins growing in early/late spring, and depends on a variety of water conditions. As the season progresses (ending in early Fall), the plants out-compete most other native plants, to form a thick/dense canopy on the water surface.
ODE modeling: Modeling watermilfoil growth in a dense patch
Total biomass over time (left: shallow water, right: deep water).
Model sensitivity. Left: end of season (EOS) biomass vs lake depth, (middle) EOS biomass vs lake transparency, (right) EOS biomass vs temperature.
Total biomass over time (left: shallow water, right: deep water).
PDE modeling: Modeling the spread and control of invasive watermilfoil
Top: control using mats (mat applied for 30 days at T = 100 days). Note the overall decrease in end of season biomass. Bottom: No control.
Top: control using mats (mat applied for 30 days at T = 100 days). Note the overall decrease in end of season biomass. Bottom: No control.