Ecology of Atlantic Shores: Conclusion

Conclusion:

Due to the very different type of sediment found at Rye than at Nahant, it was expected that there would be a significant difference between the organisms found there. It has been shown that sand grain sizes do affect the amount and type of invertebrates found in sandy beaches (Rodriguez et al 2002, Wieser 1959). However these studies were done just looking at sandy beaches, not also with salt marshes. While it is very likely that the differences in sediment is partly responsible for the variation observed, other factors like exposure, salinity, and a difference in community composition probably also have an impact on invertebrate distribution. Larger sample sizes and including more variables would be the next step for this research.

Using the Shannon index we can compare the community diversity at each study site. The Shannon index was higher at Nahant than at Rye. This shows that the community at Nahant is more even since the same amount of species were found at both locations. The evenness of the community might in part be due to the larger sediment size found in Nahant. Organisms would be able to move around more freely there than in the fine densely packed mud of Rye.

Although the variation in taxa found at different depths was not statistially significant, p-values were close to the significant .05 range. Crustaceans for example had a p-value of .078 in regards to depth. I feel that with larger sample sizes depth might prove to be a significant factor in the amount and composition of invertebrates.

No definite conclusions can be made from data obtained in Bermuda due to the inconsistent sampling. However the larger sand grains and less human activity might account for the greater species diversity seen at Whalebone Bay (as indicated by the shannon index). Larger sample sizes and better sampling methods would be needed to confirm this theory.