[MAIPC] 2 models for the spread of invasives

[Richard Gardner]

Two years ago I recognized two different models for the spread of invasive plants while walking locally. I gathered some data then, but was unable to complete either study to my satisfaction. This week I finally had the weather conditions and time to work on them. Yesterday I finished one and hope to finish the other today.

Model 1:
Galanthus - 
Model for plants such as lesser celandine in a river valley or down a watershed. Seeds float during a small period of time in the spring. During this window there needs to be the right type of rainfall to move the seeds. Site of original planting is easy to identify. 

Galanthus nivalis at Bordner Cabin, Swatara State Park, east of Harrisburg, PA. This is a great model for the flow of invasives down a watershed. One section is sheet flow of water down a hill, the other is a vernal creek which models laminar and turbulent creek flow. Both are discrete systems which are easy to follow from a distinct starting point. The sheet flow has a less distinct end point than the creek flow, but has an easily recognizable pattern. The big surprise is that Galanthus will grow on hummocks in a swamp as long as its roots are dry. It also apparently will tolerate wet roots for an undetermined time, but will not tolerate wet roots indefinitely. Main mass of plants easy to map in both situations.


Galanthus elwesii at Skinners Loops, Blue Marsh Lake, Berks County, PA. This is not as distinct a water flow pattern as at the Bornder Cabin, but still easy to follow. I was along the dry part of the lake Tuesday to see if there were plants along the shore where seeds could have floated to start new plants. There were none.

Model 2:
Muscari:
Muscari neglectum is a good model for plants which hitch hike on shoes such as garlic mustard and Japanese stilt grass. Discrete short window when seeds spread. Easy to recognize and easy to map the spread along a trail. Point of introduction should be easy to identify.

Blue Marsh, Skinners loops at the same location of the Galanthus study. Easy to follow the spread from an easily recognizable original planting.

Blue Marsh; loop trail around mile 19. Easy to follow spread along trail. Original planting should be easy to identify.


With all this said, I will not be able to work with the data until at least next winter. Therefore, is there anyone interested in working with these models or has a student who needs a project? This year's data is photos with GPS points marking the extent of the plant spread with other photos documenting the plant and the sites. I am willing to give a copy of the raw data and photos to anyone interested or take them to the sites so they can collect data for themselves. Swatara is @ 30 minutes east of Harrisburg, PA along I-78. Blue Marsh is just north of Reading, PA.

Total time in the field collecting data for either project is less than a day, probably 1/2 a day including walking to the sites. Equipment is minimal; GPS equipped camera, hiking shoes and brush pants.

The window to collect field data is short, probably 2 more weeks. We have a spare bedroom and the best cook in Berks County, PA if anyone wants to stay a night or so while working on either or both of these projects.


                                                                                                        Richard Gardner