For the dandelion 1m x 1m subplots, we found Morisita’s index to be 1.49, which means they are clumped. For the dandelion 2m x 2m subplots, we found Morisita’s index to be 1.33, which is also clumped. For the dandelion 4m x 4m subplots, we found Morisita’s index to be 1.36, which is again clumped. For the plantain 1m x 1m subplots, we found Morisita’s index to be 1.64, which is clumped. For the plantain 2m x 2m subplots, we found Morisita’s index to be 1.18, which is random dispersion. For the plantain 4m x 4m subplots, we found Morisita’s index to be 1.35, which is clumped. I believe the perception of dispersion changed with the size of the sampling unit because when you do smaller plots you are not really seeing the whole picture. If you were to take a bird’s eye view of the whole plot it would be different than just looking over the small 1m x 1m section of it. The dispersion in one subplot could be totally different than the rest of the plot. The percent error goes down when you take a bigger sample.
The reproductive traits of the plants helped control the dispersion. The dandelion has light seeds that blow off when it is windy. The area we took the plot on was on a hill and that blocked off a lot of the wind. This prevented the seeds from traveling very far so they fell off right near the original dandelion. Dandelions also reproduce asexually so this contributed to the clumped dispersion. Plantains have heavy little seeds. They fell off right near the plant so they were clumped also.
The root system contributed to the dispersion also. Dandelions have tap roots, which go straight and deep into the ground. Most of the dandelions were found on the hill. Their roots went deep enough so they would not wash away and they also didn’t have to compete with the plantains on the hill. Plantains have a hair-like network of roots near the surface. They could not survive on the hill because they would be washed away. The plantains were found mostly on flat land. These traits caused the plants to be clumped.
Lastly, the habitat traits led the plants to being clumped. Dandelions can tolerate more dry areas than plantains. The hill was dryer than the flat land so dandelions could live there without competing with plantains for the flat land. Plantains like it wetter, so they were clumped around the drain and the bottom of the hill. Dandelions can tolerate more shade so they were clumped around the tree and the plantains were more out in the open where there is more light. All these factors lead the dandelions and plantains to be clumped.