Analisis vegetasi tumbuhan bawah di Cagar Alam Gunung Abang Kabupaten Pasuruan

INDONESIA: Keanekaragaman sumber daya hayati di hutan tropis tidak hanya terbatas pada jenis pohon atau menahun, namun juga ditumbuhi tumbuhan bawah dengan keanekaragaman jenis yang tinggi. Tumbuhan bawah adalah vegetasi dasar yang terdapat di bawah tegakan hutan kecuali permudaan pohon hutan. Komunitas tumbuhan bawah terdiri dari rumput, herba dan semak. Komposisi jenis dan struktur tumbuhan bawah dapat diketahui melalui analisis vegetasi. Tujuan penelitian ini adalah untuk mengidentifikasi jenis tumbuhan bawah, mengetahui indeks keanekaragaman dan indeks nilai penting tumbuhan bawah di Cagar Alam Gunung Abang Kabupaten Pasuruan. Penelitian ini dilakukan di Cagar Alam Gunung Abang Kabupaten Pasuruan, bulan Juli 2017, menggunakan metode transek sabuk (belt transect). Dibuat transek 30 dan antar transek berjarak 200 m. Tiap transek dijadikan lima plot, sehingga jumlah seluruhnya 150 plot. Setiap plot berukuran 2 x 2 m, lalu dibuat sub plot berukuran 1 x 1 m. Diidentifikasi jenis tumbuhan bawah di Laboratorium Ekologi Jurusan Biologi, Fakultas Sains dan Teknologi, UIN Maulana Malik Ibrahim Malang. Identifikasi menggunakan kunci identifikasi Flora of Java (Backer and Brink, 1963), Flora (Steenis, 2006) dan Centre for Agriculture and Biosciences International (Cabi.org, 2017). Analisis data menggunakan Program PAST 3.14. Hasil penelitian menunjukkan bahwa tumbuhan bawah yang ditemukan sebanyak 16 famili, 33 genus dan 34 spesies. Indeks keanekaragaman diperoleh: indeks Shanon-Wiener (H’) 2,846 menunjukkan keanekaragaman tumbuhan bawah tergolong sedang dan keadaan komunitas cukup stabil; indeks kekayaan (R) Margalef 4,141 menunjukkan tingkat kekayaan tumbuhan bawah tergolong sedang; dan indeks kemerataan (E) 0,5066 menunjukkan distribusi tumbuhan bawah dalam kondisi cukup merata. Indeks Nilai Penting (INP) tumbuhan bawah tertinggi pada tumbuhan rumput dan herba adalah Cynodon dactylon sebesar 32,2478%, sedangkan terendah adalah Commelina diffusa dan Curcuma longa sebesar 0,3631%. INP tertinggi pada tumbuhan semak atau perdu adalah Tithonia diversifolia sebesar 56,3000%, sedangkan terendah adalah Solanum nigrum sebesar 4,7651%. ENGLISH: The diversity of biological resources in tropical forests is not only limited to the kinds woody plants, but also it is grown by variety lower plants that have a high diversity. Lower plants are the basic vegetation that is found under the stands of the forest except young forest trees. Lower plants community consists of grass, herbaceous and bush or shrubs. The composition of types and structure of lower plants below can be revealed through analysis of vegetation. The purpose of this research is to identify the lower plants, knowing the diversity index and the important value index of lower plants in the Nature Reserve of Mount Abang Pasuruan Regency. This research was conducted in the Nature Reserve of Mount Abang Pasuruan Regency, in July 2017, using the belt transect method. Made transect 30 and the distance of each transect is 200 m. Each transect made five plot, bringing the total to 150 entirely plot. Each plot measuring 2 x 2 m, then created a sub plot measuring 1 x 1 m. Lower plants that are found in the Laboratory of Ecology Department of biology, Faculty of Science and Technology, State Islamic University of Maulana Malik Ibrahim Malang. Identification used key Identification the Flora of Java (Backer and Brink, 1963), Flora (Steenis, 2006) and Centre for Agriculture and Biosciences International (Cabi.org, 2017). Data analysis used the Program PAST 3.14. The results showed that the lower plants that are found as many as 16 families, 33 genera and 34 species. Index of diversity acquired: Shanon-Wiener index (H ') of 2,846 indicates the lower plants diversity belongs to medium and community circumstances are quite stable; richness index (R) Margalef of 4,141 indicates the wealth level of lower plants the classified medium; and evenness index (E) of 0,5066 indicates the distribution of lower plants in conditions quite evenly. The highest Important Value Index (IVI) of grass and herbaceous plants was Cynodon dactylon of 32,22478%, while the lowest was Commelina diffusa and Curcuma longa at 0,3631%. The highest IVI in bush or shrubs is Trimonia diversifolia of 56,3000%, while the lowest is Solanum nigrum of 4,7651%