Invasive Alien Species

Species Name: Salvinia molesta

Family Name:
Salviniaceae
Synonym:
Origin:
South America.
Description:
Annual or perennial, free floating, rapid growing, branched, mat-forming fresh water fern, up to 30 cm long with slender floating rhizome. The juvenile leaves are flat on the water and only 10 mm in diameter; in the second phase they grow to 25 mm long and wide and fold upward, becoming keel- shaped; in a third stage the leaves are 38cm x 25 cm.
Without roots, only leaves alternating whorls of 3, 2 are green and floating, the third one dissected into numerous root-like filaments. Floating leaves shortly stalked, ovate oblong,  very hairy above; submerged leaf up to 4 cm long, root like, the central filaments bearing chain of sporocarps.
Invaded Habitat:
On stagnant or slow-flowing shallow water; ponds, lakes, watercourses, fishponds, lowland irrigated rice fields .  In West Java sometimes very abundant and covering the whole water surface (when  the water is stagnant or slow-moving).  A serious problems at the irrigation canals (lebung) of Gunung Madu sugar cane plantation, Central Lampung.
Distribution:
It was introduced to Indonesia in 1951 as a collection plant in Bogor Botanical Garden, escape and so far found in Sumatra, Java, Kalimantan and Papua.
Ecology:
At the third stage of growth the leaves become compact almost vertical and acutely folded; this stage develops under over-crowding conditions. The tree stages take only 2-3 weeks to occur under optimal conditions. Sporocarp formation is abundant in crowded mats. Fertile spores were not observed. Dense populations can be very noxious at the stagnant water, covering the whole water surface,  its cover so tight that it depletes oxygen supply which hampers fish and phyto-plankton growth. The thick mats can be colonized by other plants and form floating suds. Reproductions mainly by fragmentations of the rhizomes. Grow at up to 1800 m alt.
References:
  1. DIP P3T Universitas Cendrawasih,  Bagian proyek P2T Universitas Cendrawasih.  1990.  Seminar Analisis Vegetasi Gulma Air Danau Sentani di Kampus Universitas Negeri Cendrawasih Jayapura.
  2. Forno, IW., DPA. Sand and W. Sexton.  1983.  Distribution, Biology and host of Cyrtobagus singularis (Coleoptera: Curculionidae) for the biological control of  Salvinia molesta.
  3. Soerjani, M.,  A. J. G. H. Kostermans & Gembong Tjitrosoepomo (Eds.).  1987.  Weeds of Rice in Indonesia. Balai Pustaka. Jakarta.
  4. Soerjani, M. and L. Widyanto.  1979.  Preventive and Control Measures of Weeds. Proc. 5th Conference of International Weed Science Society.  Malang, Indonesia.
  5. Tjitrosoedirdjo, S.S.  1990.  Notes on The Vegetation and Manual Control of Water Hyacinth at Rawa Pening Lake, Central Java : 1989-90.  BIOTROP Special Publication No. 40.  SEAMEO BIOTROP.   Page 165-176.
  6. Tjitrosoedirdjo, S.S. and F. Widjaja.  1991.  Aquatic weed Management in Indonesia.  Biotrop Special Publication No. 40.  Bogor, Indonesia.
  7. Tjitrosoepomo, G., Soedharodjian, S. Sulastri, A. Pudjoarinto, Suyono and S. Sutanti.  1981.  Penyelidikan Gulma Air Waduk Sempor (daerah saluran induk Sempor Timur). Tim Peneliti Fakultas Biologi Universitas Gadjah Mada.  Yogyakarta.    
  8. Tjitrosoepomo, G., Soedharudjian, S. Sulastri, A. Pudjoarinto, Suyono and S. Sutanti.  1982.  Penyelidikan Gulma Air Tahap II Pada Proyek Serbaguna Kedu Selatan.  Tim Peneliti Fakultas Biologi Universitas Gadjah Mada.  Yogyakarta.  43 hal.
  9. Weber, E. 2003. Invasive Plant Species of the World. A Reference Guide to Environmental Weeds. CAB International.