Invasive SpeciesGiant knotweed

Fallopia sachalinensis
FOUND by 18Elt
ID Confirmed
Quality checked by Ms H
Peer reviewed by KB`
Field Notes
Our class went on a trip to Mackworth Island in Falmouth Maine to look to identify invasive and native species, both coastal and terrestrial. Our two sampling methods for the two species were transected data collection zone, and just looking around. The day we went it was around 55 degrees Fahrenheit and sunny, early October. The environment around us was a beach with very large rocks leading up to the greater forest part of the island. Smaller rocks covered most of the sand. The species I was looking for was the Rockweed (Fucus vesiculosus), native to Maine. The beach was covered in it, along with a bunch of other species of aquatic plants, such as spiral weed, and Knotted wrack. This environment had all sorts of living things, crabs and periwinkles took shelter in the rockweed and in tide pools, small bugs and the occasional eel were found in crevices between rocks. The ecosystem as a whole seemed to be thriving. I did notice that there were huge amounts of knotted wrack, it covered most of the ground and rocks, but it was all necessary because it was being used as a resource for the animals there. I identified the rockweed and was able to set it apart from the rest of the aquatic vegetation because of its dichotomous growth and it had heart shaped bladders. In our transect which was 6 x 6 meters, the Rockweed I found was in the range from the top part of the beach where there was no water, and to where it was completely submerged in the water. The tides change because it is located on the ocean, I think the algae has been able to adapt by being able to stay out of the water for long amounts of time. In my opinion, this species is extremely important to its environment because it provides a stable habitat for other living things. Therefore it could very well be considered a keystone species. In the forest part of the island more inwards, the places I found it in were right along the dirt trails and some were growing deep in the forest, this shows that it can grow in a variety of places. I noticed that some of it was being cut down to try to take control of all its growth, although I didn’t see any sort of restoration going on. The floor around it had little to no other species of plants, the Giant knotweed took over the entire area it was in, taking up all the space. In some parts along the path, I noticed that there were places that had vegetation competing for space. I was easily able to identify the Giant knotweed because of its size, and how it towers above the ground. The elongated heart shaped of leaves also were a major giveaway to their species. The ecosystem I saw on the island seemed to be unhealthy in some parts, in my opinion. The lack of space and the competitive plants all together are what cause this.
A sketch of our study site.
Supporting Evidence
Photo of my evidence.
The leaves of the Giant knotweed have smooth edges. The leaves have an elongated heart shape as well, in this photo they are about 23 cm long. This means that the areas that there are Gaint knotweed growing, it will look very dense because of how much space it takes up.
Photo of my evidence.
The stem of the Giant knotweed is hollow, It has small hairs on it too. This is one way to identify it and not confuse it with other species. The photo shows the inside of the stem that has a white color.
Photo of my evidence.
This photo shows the alternating leaf pattern. This means they are staggered from one side to another, the stem creates a zig-zag.
Species Observation: Species Looked For
Did you find it?: 
I think I found it
Scientific name:
Fallopia sachalinensis
Common name:
Giant knotweed
Sampling method: 
Just looking around
Photo of our sampling method.
Place Studied
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Map this species
N 43.689813 °
W -70.226570 °
Observation Site Information
A photo of our study site.
Coastal - Beach or dune
Trip Information
Mackworth Marine Transect Investigation
Trip date: 
Tue, 2018-10-09 07:36
Town or city: 
Type of investigation: 
Species Survey
Time of low tide: 
Wed, 2018-10-03 10:15



Nice photo of the hollow stem.