Vegetasi Riparian dan Kesuburan Tanah di Sub DAS Senggapa Rainforest Lodge Kedah

Abstrak. Kondisi zona riparian di sungai Senggapa Rainforest Lodge Kedah Kecamatan Blangjerango, Kabupaten Gayo Lues, Provinsi Aceh sebagian telah beralih fungsi menjadi lahan perkebunan. Alih fungsi lahan diduga berpengaruh terhadap kondisi zona riparian dan tingkat kesuburan tanah. Penelitian dilakukan dari bulan Februari hingga Juli 2021. Metode yang digunakan dalam penelitian ini adalah metode garis berpetak, terdapat 20 plot contoh dari 10 transek yang diletakkan pada sisi kiri dan sisi kanan sungai. Jenis vegetasi riparian yang ditemukan di sub DAS Senggapa Rainforest Lodge Kedah yaitu sebanyak 533 individu dari 52 jenis dan 29 suku. Indeks Nilai Penting (INP) tertinggi vegetasi riparian berdasarkan tingkat pohon dimiliki oleh Lithocarpus sp. sebesar 35,59%, INP tertinggi vegetasi riparian tingkat tiang juga dimiliki oleh  Lithocarpus sp. sebesar 34,26%, INP tertinggi vegetasi riparian tingkat pancang dimiliki oleh  Aglaia argentea dan Magnolia montana masing-masing sebesar 13,69%, INP tertinggi vegetasi riparian tingkat semai dimiliki oleh Laportea sinuata sebesar 15,56%, dan INP tertinggi vegetasi riparian tumbuhan bawah dimiliki oleh Colocasia esculenta sebesar 42,28%. Indeks keanekaragaman tingkat pohon sebesar 3,21 tergolong tinggi, tiang sebesar 2,93 tergolong sedang, pancang sebesar 3,15 tergolong tinggi, semai sebesar 3,07 tergolong tinggi, dan tumbuhan bawah sebesar 2,19 tergolong sedang. Tingkat kesuburan tanah pada stasiun I dan stasiun II sama-sama tergolong rendah, hal ini disebabkan oleh salah satu parameter kimia tanah yang dianalisis diperoleh sangat rendah. Pada area hutan lebat dan kawasan perkebunan memiliki kandungan P2O5 tanah yang tergolong sangat rendah, sehingga mempengaruhi penilaian tingkat kesuburan tanah di sub DAS Senggapa rainforest Lodge Kedah.Abstract. The condition of the riparian zone in the Senggapa Rainforest Lodge Kedah river of Blangjerango Subdistrict, Gayo Lues Regency, Aceh Province has partially switched functions into plantation land. The transfer of function is thought to affects the condition of the riparian zone and the fertility rate of the soil. The study was conducted from February to July 2021. The method used in this study was the line-transect method with 20 sample plots of 10 transects placed on the left and right sides of the river. There were 533 individuals of riparian vegetation found in the Sub watershed Senggapa Rainforest Lodge Kedah consisting of 52 species and 29 families. The highest Importance Value Index (IVI) of riparian vegetation based on the tree level was found in Lithocarpus sp. at 35.59%. The highest IVI of riparian vegetation at the pole level was also found in Lithocarpus sp. at 34.26%. The highest IVI of riparian vegetation at the stake level were found in Aglaia argentea and Magnolia montana at13.69%. The highest IVI of riparian vegetation at the seedling level was found in Laportea sinuata at 15.56%, and the highest IVI of riparian vegetation of the lower plants was found in Colocasia esculenta at 42.28%. The diversity index of riparian vegetation is 3.21 at the tree level which is classified as high, 2.93 at the pole level which is classified as moderate, 3.15 at the stake level which is classified as high, 3.07 at the seedling level which is classified as high, and 2.19 at lower plants level which is classified as moderate. The fertility rate of soil both at station I and station II is relatively low. This is due to one of the chemical parameters of the analyzed soil was obtained very low. In areas of dense forest and plantation areas, the P2O5 soil content is classified as very low, thus affecting the assessment of soil fertility level in sub watershed Senggapa rainforest Lodge Kedah.