The Distribution and Morphological Variation of Polypodium polypodioides (Resurrection Fern) from the Immediate Coastal Area to Further Inland on Ossabaw Island Southern End

by

Greg Bryant

Melissa Bright

Tom Jursik 

TPTE 595

Dr. Claudia Melear

Experiment Conducted On Ossabaw Island

May 26-June 6, 2001

Preface

This preface is included to emphasize that the best intentions of scientific inquiry are often at the mercy of the whims of nature. Our team learned first hand this valuable lesson as we attempted three experiments altogether before achieving success. The detailsof these attempts can be found in Tom Jursik’s field journal on pp. 14-15, 21-22, and 26-31. Our first attempt was to set up scent stations on the island to determine the type of animal activity taking place near camp.Weather did not cooperate as we were rained out by two consecutive summer rains. This was disappointing as we had planned to carry this study on for an extended period of time and had spent considerable time and effort in preparation. 

Upon completing our species meditation,fiddler crabs seemed to be an interesting topic. We embarked upon a study to find out more about their social hierarchy. This attempt was foiled by the high tides. We realized that experimental results were expected by Dr. Cruzan that evening, so time and tide did not permit our continuation of this study. Needless to say, careful preparation is of the essence, but does not insure success.

Abstract

This study was done in attempt to learn more about the Resurrection Fern, Polypodium polypodioides. We were interested in its range in the coastal areas of Ossabaw Island off the coast of Georgia. This fern is a common enough species in the southeastern United States, but seemed abundant in this particular locale. We wanted to find out if there was any variance within its range on the island itself.

Introduction

The fern is a plant that has a rather interesting life cycle, more than merely seed, seedling, and adult. A mature fern produces a cluster of sporangia containing spores, which are eventually released. These spores grow into a small plant known as a prothallus which accomplishes self- fertilization. The results of this process is a young fern, grown from a fertilized “egg”. Spores eventually develop on the mature plant and the process begins all over again. On Ossabaw, an abundance of Resurrection Ferns are found. They have a behavior of appearing to curl up and die when they are dry, and they seem to prefer growth in the branches of Live Oak trees.

Problem

Our problem was to determine if the distribution of Resurrection Ferns varied from the immediate coastal area to further inland.

Methods and Materials

Our methods and materials were rather simple. We decided to examine only a certain portion of each tree so that each sample would be consistent. We chose limbs that were six meters from the ground and on or near a horizontal plane. We also selected only limbs that were oriented towards the west. Using a compass and measuring tape, each limb was selected. Ferns were counted in a two meter section of limb starting one meter from the main trunk. We took five samples within 100m of the shore, and five samples approximately .75 miles inland.Because of the number of ferns, two group members counted and an average was taken from their results,( see chart).

Results

We found a significant difference in the number of ferns inland compared with those found near to the shore zone. Ferns in the shore area were less abundant, and their number increased greatly as we proceeded inland. During the first week, we found that there were 44.2 % more ferns inland than near the shore.

After conferring with Dr. Cruzan, it was decided to take further samples on different parts of the island. During the second week, sample were taken on and near the South Beach area. Our samples showed the same trend as the first week, only more drastically so. On South Beach, the forest is much closer to the water. Ferns in this area were non-existent, and further inland, their numbers were much lower than before (see charts in appendices).

Discussion / Conclusion

We can conclude from this short study that Resurrection Ferns do vary in their distribution from shore to inland areas. Their numbers do increase as we proceed inland. This result brings up several questions. It would be interesting to do further studies to find out the reason for this difference in numbers. One possibility might be the salinity of the air near the shore as opposed to further inland. Another question is why do these ferns seem to prefer growing on the limbs of Live Oak trees. Although the ferns have a broad range in the southeastern part of the country, the Live Oaks do not enjoy this wide distribution.On Ossabaw Island, the oaks seem to be the habitat of choice for the ferns.

Bibliography

Alden, Peter and Nelson, Gil.National Audubon Field Guide to theSoutheastern States, New York : Alfred A. Knopf, 1999.

Hallowell, Anne C. and Hallowell, Barbara G.Fern Finder, Berkeley: Nature Study Guild, 1981.

Johnson, Robert G. A Naturalist’s Notebook , Kingsport: Kingsport Press, 1984.

Appendices

Week One Samples Chart: Polypodium polypodiode

Week Two Samples Chart: Polypodium polypodiodes