The sampling point is Karekare swamp in Rarotonga Island. Arecaceae pollen grains are dominant in all layers. While Barringtonia pollen decreases rapidly in the upper part. The appearance ratio of Pandanus pollen is high in the lower part, but it decreases rapidly in upper layers. The appearance ratio of herbaceous plants such as Poaceae and Cyperaceae is remarkable in the upper layers. Considering that Barringtonia and Pandanus grow in the hinterland of mangrove forests, decrease in Barringtonia and Pandanus and increases in herbaceous plants suggest a disturbance of the hinterland vegetation.