1. The purpose of this experiment is to identify and analyze the
relationship between pH of the environment and the population
of cutaneous respirators. The northern two-lined salamander (E.
bislineata), the eastern red-backed salamander (P. cinereus), the
southern chorus frog (P. nigrita), and the common earthworm
(L. terrestris) breathe through the skin in a method called
cutaneous respiration. The transfer of vital gases is strongly
affected by the contact between the skin and factors in the
environment such as acidity. New information resulting from
this study on microhabitat tolerance can be considered for using
cutaneous respirators as an index to forest health in the future.
Examining how pH affects these organisms is important because
of their roles in the ecosystem and the concern of habitat
destruction by acid rain. The null hypothesis was that there
would be no correlation between pH and population of
cutaneous respirators.
The null hypothesis was rejected only for earthworms. (Hor=0 can
be rejected in favor of Har≠0 for the correlation between pH and
earthworms only). There was a weak positive correlation between
soil pH and population of common earthworms (L. terrestris). The
Pearson correlation test result for earthworms (0.3747) is the only
one greater than the critical value of 0.3687. There is no
correlation between pH and any of the other species. The peak
populations were found where the pH was 7 to 8. The correlation
is not strong enough to support the use of earthworms as an index
to forest pH. There is only a 14.04% chance that pH influences the
population of earthworms as shown by the r2 value. There was a
greater frequency of boards found with a neutral to basic pH than
acidic. If there were more boards with an acidic pH level, there
would be statistically more chances of cutaneous respirators being
found in acidic areas. However, this study does show that
cutaneous respirators prefer a neutral or slightly basic
environment. This supports the concern that acid rain pollution is
damaging to the organisms of a deciduous forest ecosystem.
Acknowledgements: I would like to thank my teacher, Ms. Peggy Brosnan for guiding me through the research process.
In addition, I want to thank a staff member at Watkins Regional Park , Ms. Paula McNeil, for helping us identify organisms.
1. 41 1-foot by 1-foot plywood boards at the site were labeled
with numbered orange flags before collection of data for
identification purposes. The boards were placed about six to
ten feet apart along the edge of a stream at Watkins Regional
Park. The boards were visited once a week over 3 months
2. With each visit to the site, the Koolertron Home Garden Soil
Tester Light Moisture pH Meter 3 in 1 meter was imbedded in
the soil near each board. Each board was lifted and any species
found under it were documented, on the data sheet as well as
photographically
3. Each board was placed back into its original position and the pH
value was recorded.
Pearson Correlation Test Results (r critical value=0.3687)
r2
Salamanders 0.3222 0.1038
Southern Chorus Frog 0.2392 0.0572
Common Earthworm 0.3747 0.1404
Total 0.3576 0.1278
Linda Kuo
Koolertron Home Garden Soil Tester Light
Moisture pH Meter 3 in 1 meter
Eastern red-backed salamander in a lead color
phase