Analisis Kerapatan Vegetasi Mangrove dan Kaitannya sebagai Mitigasi Abrasi dan Pelindung Pantai di Pantai Sei Tuan Indah Kecamatan Pantai Labu Kabupaten Deli Serdang

Abstract

The mangrove ecosystem is the most important coastal vegetation along the coast because it can help reduce damage by tidal waves. Mangroves with dense conditions are able to dampen waves more strongly than mangroves with rare or damaged conditions. Decreasing mangrove cover on a large scale will physically reduce its function as a stabilizer for the coastline, preventing abrasion, trapping silt and sediment. The mangrove rehabilitation area at Sei Tuan Indah Beach has eroded the shoreline due to tides so that some of the mangroves have died. The purpose of this study was to determine the type and density of mangrove vegetation on Sei Tuan Indah Beach and the effect of mangrove density on sedimentation and abrasion transport rates on Sei Tuan Indah Beach. Determination of research stations using purposive sampling method by specifying 2 stations to represent each location. Mangrove identification is carried out directly in the field and density calculations are carried out at the location using the transect method . Sedimentation rate was measured using a sediment trap with a diameter of 4 inches and a height of 30 cm. The results of species identification revealed that there were 5 mangrove species obtained, including Avicennia marina , Achantus ilicifolius , Bruguiera sexangula , Rhizophora apiculata , and Rhizophora mucronata . The tree density value at station 1 was 400 ind/ha, at station 2 it was obtained 3600 ind/ha and station 3 was 1400 ind/ha. The sapling category at station 1 obtained 100 ind/ha, at station 2 it was 300 ind/ha while for station 3 it was obtained 1400 ind/ha. For the seedling category, at station 1 it was not found, at station 2 it was obtained 300 ind/ha while at station 3 it was obtained 1100 ind/ha. The relationship between mangrove density affects the sedimentation transport rate where both show an opposite relationship, which means that the higher the mangrove density, the lower the sedimentation rate, and vice versa.