Thirty scientists, researchers, and academicians participated in a symposium on managing invasive alien species organized by the SEAMEO Biotrop on 23 July 2010 at Sanur, Bali, Indonesia. The symposium was one of the activities during the annual meeting of the International Association of Tropical Biology (ATBC) held on 23-26 July 2010.
The symposium was aimed to level off knowledge and practices among the participants in better understanding and managing alien plant species. Alien plant species invasion is occurring practically in all landscapes on earth through various patterns and processes. In most cases, this phenomenon has been attributed to human migrations. The impacts of invasion, which are usually regarded negatively, vary from place to place together with the ways the invasion is being mitigated and/or moderated. The challenge to generate a global action to address this issue seems to be posed by the quality and availability of information on this matter. Thus, ten speakers from Australia, Africa, Hawaii, Indonesia, Korea, Puerto Rico and Singapore were invited to present their project experiences along this aim. The topics presented and their corresponding speakers were as follows:
1. Native latitudinal range and growth habit predict progression through the plant continuum on a tropical island by Giam Xingli, Kwek Yan Chong and Hugh T.W. Tan
2. Invasion by native tree species prevents biotic homogenization of Puerto Rico by Abelleira Martinez and J. Oscar
3. Alien plant invasions in tropical and sub-tropical savannas: patterns, prospects by Marcel Rejmanek et al.
4. Grass as human footprints by Alex Sumadijaya.
5. High potential for seed dispersal by an introduced predator (Rattus rattus) by Aaron Shields, Samantha S. Setterfield and Keith Ferdinands.
6. History matters: divergent ecological correlates of abundance of the exotic Andropogon gayanus in early and late stages of invasion by Aaron Petty, .
7. Role of phenotypic plasticity in the invasiveness of a grass species important by Sampaio, Alexandre B., Curtis Daehler, Vania Pivello, Agno Damasceno.
8. The uses and limits of habitat suitability models for invasive species; a case study grass invading a tropical Australia floodplain by Dongwook Ko, Samantha S. Setterfield, Yvonne Buckley, Kieth Ferdinands, Aaron Petty & Michael Douglas.
9. Invasive plant species posed a great problems forest rehabilitation by Soekisman Tjitrosoedirdjo, Sri S. Tjitrosoedirdjo, Soekotjo, & A. Subiakto.
10. Database development of Indonesian invasive alien plant species by Sri S. Tjitrosoedirdjo, S. Tjitrosoedirdjo, N. Suminah & Pujantoro.
In his written remarks that was read during the opening of the symposium, Mr. Ahmed Djoghlaf, Executive Secretary of the Convention on Biodiversity (CBD), shared the impacts of invasive alien species to biodiversity and national economy causing huge losses in water management, disease control, agriculture, forestry and aquatic productions. He emphasized the need to prevent the introduction of alien species to save large-scale environmental costs and support national development. He recognized the symposium as the opportune time prior to the Conference of Parties 10 to identify the existing issues on invasive alien species and to discuss a biodiversity strategic plan with specific relevancy to Indonesia.
Dr. Bambang Purwantara and Dr. Sri S. Tjitrosoedirdjo, SEAMEO Biotrop Director and scientist, respectively, coordinated the implementation of the symposium. Dr. Bambang also served as convenor during the symposium.
The symposium paid a considerable effort on the mechanism of biological invasions and much less on their management ; biological traits (phenotypic or genetic ) , width of native range distribution, as well as availability of suitable area to be invaded, and the availability of propagule spreading agents were particularly highlighted as supporting factor on invasion. While a considerable African grasses were found invading grassland in Australia and new world, it did not happen on the opposite, the existence of bigger herbivores in Africa seemed to be contributing factor. A condition when an agricultural production system collapsed. and the existing vegetation was replaced and dominated by an invasive alien plant species, the local species still encroached the dominated area and prevented from homoginaton of the invading invasive species. The invasive alien plant species indeed posed a great problem of environmental rehabilitation. It seemed important to collate and organize the data on invasive alien species and their distribution to develop their management.
Further research on the management of IAS will be badly needed to prevent further invasions.