A comparative Study of the Population Densities of Various Tardigrada Species
Baldree, Cheryl Marie
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SubjectTardigrada; Trees--Iowa--Polk County; Animal population density; Dust-fall; Automobiles--Motors--Exhaust gas
The problem. The purpose of this investigation was to compare the population density of tardigrades in regions as related to: (a) high and low particulate counts without reference to the nature of the particulate present and (b)high and low traffic flow density without reference to particulate counts. Procedure. Bark-lichen samples were collected from 12 species of deciduous trees from 12 locations in Polk County, Iowa. The regions varied in particulate count, measured in tons of dust fall per month, and traffic flow density, measured in number of cars per year. Tardigrades were collected from samples, mounted in lactophenol, and identified. The area of bark-lichen samples was measured and the densities calculated in number of tardigrades per square centimeter. Findings. It appears from this study that tardigrades are sensitive to high amounts of dust fall and high amounts of automobile exhaust. Conclusions. There appears to be a direct relationship between tardigrade population density and particulate count and traffic flow density. The higher the particulate count the lower the population density of tardigrades. The higher the traffic flow density the lower the tardigrade population density. Recommendations. More work needs to be done in this area. There are many variables to take into consideration. Tardigrades may require certain conditions for growth which were not accounted for in this study. More needs to be learned about the tardigrade itself before this study becomes meaningful.