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An inventory of the alien plant species in Indonesia based on the existing references and herbarium specimens concluded that 1936 alien plant species are found in Indonesia which belong to 187 families. Field studies should be done to get the complete figures of alien plant species in Indonesia. Based on the existing figures of the plant species, the invasive alien plant species can be identified, followed by studies on the assessment of losses, biology, management and their possible utilizations. Alien plant species are imported to Indonesia for cultivation, collection of the botanical garden, as experimental plants or other curiosities. Aside from plants purposely imported, there are also introduced plant propagules contaminating imported agricultural products. These alien plant species can be beneficial or have a potential of being invasive. The alien cultivated species consisted of 67% of the total number. More than half of the cultivated plants are ornamental plants. Some of the species are naturalized or escaped from cultivation and become wild and invasive. Some other naturalized species, adapted well without any problems of invasion. There are 339 species or 17% of the species recorded as weeds. The highest record of weeds is found in the family of Poaceae (57 species), followed by Asteraceae (53 species) and Cyperaceae (35 species). There are 6 families having more than 10 species of weeds: Amaranthaceae, Asteraceae, Cyperaceae, Euphorbiaceae, Poaceae, and Rubiaceae. Three families have more than 100 species: Asteraceae 162 species, Poaceae 120 species, and Papillionaceae 103 species. Five species of aquatic and 20 species of terrestrial plants considered as important alien plant species in Indonesia were identified and some of their distributions noted. Keywords: Alien plant species/Invasive alien plants/Weeds/Environmental weeds/Aquatic and terrestrial alien plants

Disturbances caused by the conversion of rain forests into agricultural systems provide an opportunity for the expansion of Invasive Plant Species (IPS). Bukit Duabelas National Park is one of the few remaining lowland forests in Jambi Province (Sumatera, Indonesia). The surrounding areas up to the national park borders have already been converted into jungle rubber agroforests as well as rubber and oil palm plantations which might lead to an increased spread of IPS into the forest. This study was aimed at compiling a list of IPS and determining their distribution and coverage of IPS in four land use systems (rain forest jungle rubber, rubber and oil palm plantations). Spatial distribution patterns were investigated by creating a horizontal vegetation profile diagram for the permanent plots of the EFForTS project (Ecological and Socioeconomic Functions of Tropical Lowland Rainforest Transformation Systems, http://www.uni-goettingen.de/crc990). The dominance of IPS was determined using Important Value Index. A total of forty IPS were identified across the four land-use systems. The numbers of IPS were the highest in oil palm (28 species) and rubber plantations (27 species), and the lowest in jungle rubber (10 species). IPS were absent in the lowland rain forest. The diversity of IPS was influenced by environmental factors, especially canopy openness. IPS with the highest ground coverage were Dicranopteris linearis and Clidemia hirta. Both of them were found in all three land-use systems outside the rain forest when the forest canopy opens due to illegal logging or other human disturbances. Therefore, reforestation of disturbed areas is recommended to prevent the spread of IPS.

An account of the tribe composition, endemic taxa, comparison with ad jacent areas and weedy Asteraceae of Sumatera is given. Based on the records of January 2000, there are 133 species of 74 genera in 11 tribes. The tribe Heliantheae is the largest, with 28% of the total number of the genera, followed by Astereae with 15%, Inuleae 12%, Senecioneae 10%, Anthemideae, Eupatorieae and Lactuceae 8%, the other tribes are represented by 4% or less. The most diverse genus is Blumea with 14 species. Other genera are only represented by 10 species or less, usually 4, or 3, or 2, and mostly by 1 species only. Thirty nine or about 53% are exotic genera and the native ones are less than half of the total number of the genera. In terms of indigenous and endemic species, Sumatera is richer than Java. There are 1 genus, 7 species and 2 varieties of Asteraceae endemic to Sumatera. A number of 43 important weed species were introduced from Tropical America, Africa, Asia and Europe. Among these Chromolaena odorata and Mikania micrantha are reported as the most noxious ones. List of the genera and species recorded in Sumatera is provided in this paper.

An account of the tribe composition, endemic taxa, comparison with adjacent areas and weedy Asteraceae of Sumatera is given. Based on the records of January 2000, there are 133 species of 74 genera in 11 tribes. The tribe Heliantheae is the largest, with 28% of the total number of the genera, followed by Astereae with 15%, Inuleae 12%, Senecioneae 10%, Anthemideae, Eupatorieae and Lactuceae 8%, the other tribes are represented by 4% or less. The most diverse genus is Blumea with 14 species. Other genera are only represented by 10 species or less, usually 4, or 3, or 2, and mostly by 1 species only. Thirty nine or about 53% are exotic genera and the native ones are less than half of the total number of the genera. In terms of indigenous and endemic species, Sumatera is richer than Java. There are 1 genus, 7 species and 2 varieties of Asteraceae endemic to Sumatera. A number of 43 important weed species were introduced from Tropical America, Africa, Asia and Europe. Among these Chromolaena odorata and Mikania micrantha are reported as the most noxious ones. List of the genera and species recorded in Sumatera is provided in this paper. Key words : Asteraceae/Sumatera/compositions/endemic species/distribution/weedy Asteraceae