| Zusammenfassung: | This study classified plant communities and examined the environmental correlates of community compositions in two submontane rainforests on the ranges of Eastern Arc Mountains, Tanzania. Using agglomerative cluster analysis, indicator species analysis and non-metric multidimensional scaling (NMS) ordination, based on importance value of tree species, five distinct plant communities were identified in the Usambara and six in the Uluguru mountains.The communities corresponded closely to variations in topography and soil physical and chemical properties. The different communities occurred on clay soils in lower elevations and on sandy-clay to sandy-clay-loam soils in higher elevations. Two topographic and 14 edaphic factors were significant correlates of plant community composition. Elevation was the strongest correlate of community composition on individual mountain range followed by percent clay and soil pH. Landform index and soil Na concentration were the major factors in separating plant communities on the west Usambara and Uluguru Mountains. There were appreciable variations in plant community compositions and patterns on the two mountain ranges.The results suggest that plant community patterns in the Eastern Arc Mountains vary from one range to another and are influenced by a complex of local heterogeneity in topographic and edaphic factors.The complex of factors influencing plant distribution can have a big bearing in species restoration and biodiversity conservation in the Eastern Arc Mountains. Kajian ini mengelaskan komuniti tumbuhan dan mengkaji faktor korelasi alam sekitar bagi komposisi komuniti dua hutan hujan subgunung di banjaran Pergunungan Arka Timur, Tanzania. Dengan menggunakan analisis kelompok aglomerat, analisis spesies penunjuk dan penskalaan berbilang matra (NMS), dan berasaskan indeks nilai kepentingan spesies pokok, lima komuniti yang jelas dikenal pasti di pergunungan Usambara and enam di pergunungan Uluguru. Komuniti tersebut sepadan dengan variasi topografi serta sifat fizikal dan kimia tanih. Pada aras ketinggian yang lebih rendah, komuniti yang berbeza i tu wujud di atas tanah liat manakala di aras yang lebih tinggi, komuniti tersebut terdapat di tanih campuran pasir, tanah liat dan loam. Dua faktor topografi dan 14 faktor edafik merupakan faktor korelasi yang signifikan bagi komposisi komuniti tumbuhan.Ketinggian merupakan faktor korelasi yang terkuat bagi komposisi komuniti di banjaran pergunungan. Ini diikuti oleh peratus tanah liat dan pH tanih. Indeks bentuk tanah dan kepekatan Na tanih ialah faktor utama yang memisahkan komuniti tumbuhan di Pergunungan Usambara barat dan Pergunungan Uluguru.Terdapat variasi yang agak besar dalam komposisi serta corak komuniti tumbuhan di kedua-dua banjaran pergunungan. Keputusan kami mencadangkan bahawa corak komuniti tumbuhan di Pergunungan Arka Timur berbeza daripada satu banjaran kepada yang lain dan dipengaruhi oleh pelbagai keheterogenan tempatan dalam faktor topografi serta edafik. Faktor-faktor ini yang mempengaruhi taburan tumbuhan memberi kesan besar dalam pemulihan spesies serta pemuliharaan biodiversiti di Pergunungan Arka Timur.
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