Invertebrate Pomatogeton populations.

Abstract

1. During the summer of 1967 at UMBS an observational study was made of the invertebrate population assocaited with Potamogeton illinoensis. 2. A taxonomic list of th einvertebrates identified was made. 3. Most of th ephyla found can occur at any region of the plant. 4. Plumatella repens and Hydra oligactis show preference for specific levels--the former for lower areas, the latter for upper areas. As a result their associated communities also show some vertical stratification. 5. Stratification is probably a factor of light intensity and relative age of the plant leaves. 6. Suctorians are the primary animal invaders in the progression that occurs on new slides immersed in the lake. These animals increase in numbers for six days, by the twelfth day they disappear. Their disappearance is correlated with an increase of diatoms and fecal material present on the slides. 7. Suctorians attach in greater numbers to a slide with a greater exposure to water currents. They will continue to survive where there is little accumulation of organic material. 8. There is no evidence to show that the progression that occurs on slides is the same progression that occurs on Potamogeton leaves.